WO2013084657A1 - Radiation imaging device - Google Patents
Radiation imaging device Download PDFInfo
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- WO2013084657A1 WO2013084657A1 PCT/JP2012/079004 JP2012079004W WO2013084657A1 WO 2013084657 A1 WO2013084657 A1 WO 2013084657A1 JP 2012079004 W JP2012079004 W JP 2012079004W WO 2013084657 A1 WO2013084657 A1 WO 2013084657A1
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/48—Diagnostic techniques
- A61B6/484—Diagnostic techniques involving phase contrast X-ray imaging
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
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- G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
- G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
- G21K2207/00—Particular details of imaging devices or methods using ionizing electromagnetic radiation such as X-rays or gamma rays
- G21K2207/005—Methods and devices obtaining contrast from non-absorbing interaction of the radiation with matter, e.g. phase contrast
Definitions
- the present invention relates to a radiation imaging apparatus.
- X-rays are used as a probe for seeing through the inside of a subject because they have characteristics such as attenuation depending on the atomic numbers of elements constituting the substance and the density and thickness of the substance.
- X-ray imaging is widely used in fields such as medical diagnosis and non-destructive inspection.
- a subject In general X-ray imaging, a subject is placed between an X-ray source that emits X-rays and an X-ray image detector that detects an X-ray image, and a transmission image of the subject is captured.
- each X-ray radiated from the X-ray source toward the X-ray image detector has characteristics (atomic number, density, thickness) of the substance constituting the subject existing on the path to the X-ray image detector. ), The light is incident on the X-ray image detector.
- an X-ray transmission image of the subject is detected and imaged by the X-ray image detector.
- X-ray image detectors include a combination of an X-ray intensifying screen and film, a stimulable phosphor (accumulating phosphor), and a flat panel detector (FPD: Flat Panel Detector) using a semiconductor circuit. Widely used.
- the X-ray absorptivity becomes lower as a substance composed of an element having a smaller atomic number, and the difference in the X-ray absorptivity is small in a soft tissue or soft material of a living body.
- most of the components of the cartilage part constituting the joint of the human body and the joint fluid in the vicinity thereof are water, and the difference in the amount of X-ray absorption between the two is small, so that it is difficult to obtain image contrast.
- an X-ray phase for obtaining an image (hereinafter referred to as a phase contrast image) based on an X-ray phase change (angle change) by an object instead of an X-ray intensity change by an object.
- Imaging research is actively conducted. In general, it is known that when X-rays are incident on an object, the interaction is higher in phase than in X-ray intensity.
- a first diffraction grating (phase type grating or absorption type grating) is arranged behind a subject, and a specific distance (Talbot interference distance) determined by the grating pitch of the first diffraction grating and the X-ray wavelength.
- the second diffraction grating (absorption type grating) is disposed only downstream, and the X-ray image detector is disposed behind the second diffraction grating.
- the Talbot interference distance is a distance at which X-rays that have passed through the first diffraction grating form a self-image (hereinafter referred to as a G1 image) that exhibits a periodic intensity distribution due to the Talbot interference effect.
- a G1 image self-image
- the moiré fringes generated by the superposition of the G1 image and the second diffraction grating are detected, and the phase of the subject is analyzed by analyzing the modulation of the periodic pattern appearing in the image corresponding to the moire fringes.
- a fringe scanning method is known as a method for analyzing a periodic pattern appearing in an image.
- the second diffraction grating is arranged with respect to the first diffraction grating in a direction substantially parallel to the plane of the first diffraction grating and substantially parallel to the grating pitch direction of the first diffraction grating.
- the phase shift derivative obtained by the fringe scanning method is related to the grating pitch direction of the first diffraction grating, and the phase contrast image obtained based on this phase shift derivative includes an object that intersects the grating pitch direction.
- the edge of the subject substantially perpendicular to the lattice pitch direction is clearly depicted. That is, the arrangement of the subject is restricted by the grating pitch direction of the first diffraction grating.
- an X-ray source, a first diffraction grating, a second diffraction grating, a detector, and a subject table arranged in a vertical direction are provided by an arm member. It is a so-called vertical X-ray imaging apparatus that is supported, and the object table is disposed between the X-ray source and the first diffraction grating, or between the first diffraction grating and the second diffraction grating. Is done.
- the arm member is provided adjacent to the subject table in the direction of the grating pitch of the first diffraction grating. According to this configuration, a relatively long subject such as an arm or a leg can be placed on the grating pitch of the first diffraction grating. The arm member can become an obstacle when it is arranged along the direction.
- the present invention has been made in view of the above-described circumstances, and an object thereof is to provide a radiation imaging apparatus capable of appropriately arranging a subject and obtaining a clear phase contrast image.
- a first radiation image including a radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and including a periodic intensity distribution through the radiation emitted from the radiation irradiation unit.
- a second grating that forms a second radiation image including a periodic intensity distribution by partially shielding the first radiation image, and the second radiation image.
- a radiation image detector for detecting and acquiring image data; and the radiation irradiating unit, the first grating, the second grating, and the radiation image detector extending in an arrangement direction of the radiation irradiating unit, And a first support member that supports the first grating, the second grating, and the radiation image detector, wherein the first support member places the first grating in the arrangement direction of the linear bodies.
- a radiography apparatus arranged out of the extension area.
- the first support member when the subject is arranged along the arrangement direction of the linear body group of the first lattice, the first support member does not become an obstacle, and the subject is appropriately arranged to be clear. A phase contrast image can be obtained.
- FIG. 12 is a schematic diagram for explaining a modification of the method for generating the phase contrast image of FIG. 11.
- FIG. 1 shows a configuration of an example of a radiographic apparatus for explaining an embodiment of the present invention
- FIG. 2 shows a control block of the radiographic apparatus of FIG.
- the X-ray imaging apparatus 1 is roughly divided into an X-ray imaging apparatus main body 2 and a console 3.
- the X-ray imaging apparatus body 2 includes an X-ray irradiation unit 11 that irradiates the subject H with X-rays, and an imaging unit that detects X-rays emitted from the X-ray irradiation unit 11 and transmitted through the subject H, and generates image data.
- the console 3 controls the exposure operation of the X-ray irradiation unit 11 and the imaging operation of the imaging unit 12 of the X-ray imaging apparatus body 2 based on the operation of the operator, and calculates image data acquired by the imaging unit 12 Process to generate a phase contrast image.
- the X-ray irradiation unit 11 and the imaging unit 12 are supported by a stand 13 installed on the floor.
- the stand 13 includes a base 60 fixed to the floor and an arm member 61 extending from the base 60 in the vertical direction (z direction in the illustrated example).
- the X-ray irradiation unit 11 is attached to the distal end portion of the arm member 61.
- the imaging unit 12 is disposed to face the X-ray irradiation unit 11 and is attached to a substantially central portion of the arm member 61.
- the X-ray irradiation unit 11 includes an X-ray tube 18 as an X-ray source and a collimator unit 19.
- the X-ray tube 18 is of an anode rotating type, and is a filament (not shown) as an electron emission source (cathode) according to a high voltage applied from the high voltage generator 16 based on the control of the X-ray source control unit 17.
- X-rays are generated by emitting an electron beam from the motor and causing it to collide with the rotating anode 18a rotating at a predetermined speed. The colliding portion of the rotating anode 18a with the electron beam becomes the X-ray focal point 18b.
- the collimator unit 19 has a movable collimator 19 a that limits the irradiation field so as to shield a portion of the X-rays emitted from the X-ray tube 18 that does not contribute to the inspection area of the subject H.
- the imaging unit 12 includes an X-ray image formed by a first absorption type grating 31 for detecting an X-ray phase change (angle change) caused by the subject H and an X-ray that has passed through the first absorption type grating 31. And a detection unit 14 that detects (hereinafter, this X-ray image is referred to as a G1 image). Although the details will be described later, the X-ray imaging apparatus 1 generates a phase contrast image using a fringe scanning method.
- the detection unit 14 includes a second absorption grating 32 superimposed on the G1 image, An X-ray image detector 30 that detects the G1 image on which the second absorption type grating 32 is superimposed, and a scanning mechanism 33 that translates the second absorption type grating 32 at a predetermined pitch are provided.
- the scanning mechanism 33 is configured by an actuator such as a piezoelectric element, for example.
- the imaging unit 12 is configured as a unit in which the first absorption type grating 31 and the detection unit 14 (the second absorption type grating 32 and the X-ray image detector 30) are housed in one housing.
- the first absorption type grating 31, the second absorption type grating 32, and the X-ray image detector 30 are individually housed in appropriate housings, and individually. You may make it attach to the arm member 61.
- first absorption type grating 31, the second absorption type grating 32, and the X-ray image detector 30 may be appropriately combined to be unitized and attached to the arm member 61, for example, the first absorption type The mold grating 31 and the second absorption grating 32 may be unitized and attached to the arm member 61, and only the X-ray image detector 30 may be attached alone to the arm member 61, or the second absorption grating 32 may be attached.
- the X-ray image detector 30 may be unitized and attached to the arm member 61, and only the first absorption type grating 31 may be attached to the arm member 61 alone.
- the subject table 15 on which the subject H is placed is attached to the arm member 61 that supports the X-ray irradiation unit 11 and the imaging unit 12.
- the subject table 15 is disposed between the X-ray irradiation unit 11 and the imaging unit 12, more specifically, between the X-ray irradiation unit 11 and the first absorption grating 31.
- the console 3 is provided with a control device 20 comprising a CPU, ROM, RAM and the like.
- the control device 20 includes an input device 21 through which an operator inputs an imaging instruction and the content of the instruction, an arithmetic processing unit 22 that performs arithmetic processing on the image data acquired by the imaging unit 12 and generates an X-ray image, and X A storage unit 23 for storing line images, a monitor 24 for displaying X-ray images and the like, and an interface (I / F) 25 connected to each unit of the X-ray imaging apparatus 1 are connected via a bus 26. .
- a switch, a touch panel, a mouse, a keyboard, or the like can be used as the input device 21, for example, a switch, a touch panel, a mouse, a keyboard, or the like can be used.
- X-ray imaging conditions such as X-ray tube voltage and X-ray irradiation time, imaging timing, and the like.
- the monitor 24 includes a liquid crystal display or the like, and displays characters such as X-ray imaging conditions and X-ray images under the control of the control device 20.
- the first absorption type grating 31 includes a substrate 31a and a plurality of X-ray shielding portions 31b (high radiation absorption portions) disposed on the substrate 31a.
- the second absorption grating 32 includes a substrate 32a and a plurality of X-ray shielding portions 32b (high radiation absorption portions) arranged on the substrate 32a.
- the substrates 31a and 32a are each formed of an X-ray transmissive member such as silicon, glass, resin, or the like that transmits X-rays.
- the X-ray shielding part 31 b is configured by a linear member extending in one direction in a plane orthogonal to the optical axis C of the X-rays emitted from the X-ray irradiation part 11.
- a material of each X-ray shielding part 31b a material excellent in X-ray absorption is preferable, and for example, a heavy metal such as gold or platinum is preferable.
- These X-ray shielding portions 31b can be formed by a metal plating method or a vapor deposition method.
- the X-ray shielding portion 31b is in a plane perpendicular to the optical axis C of the X-ray, the direction (hereinafter, x and direction) orthogonal to the one direction at a constant grating pitch p 1 to each other a predetermined distance d 1 is arranged with a gap.
- the X-ray shielding part 32b is also composed of a linear member extending in one direction in a plane perpendicular to the optical axis C of the X-rays emitted from the X-ray irradiation part 11.
- a material of each X-ray shielding part 32b a material having excellent X-ray absorption such as heavy metals such as gold and platinum is preferable, and these X-ray shielding parts 32b can be formed by a metal plating method or a vapor deposition method. is there.
- X-ray shielding portion 32b in the plane orthogonal to the optical axis C of the X-ray, at a constant grating pitch p 2 in the direction (x-direction) orthogonal to the one direction, at a predetermined interval d 2 from each other Are arranged.
- the first and second absorption gratings 31 and 32 configured as described above do not give a phase difference to incident X-rays but give an intensity difference, they are also called amplitude gratings.
- the slit portions (low radiation absorbing portions) that are the regions of the distances d 1 and d 2 may not be voids.
- the gaps may be filled with an X-ray low absorbing material such as a polymer or a light metal. Good.
- the first and second absorption type gratings 31 and 32 are configured to project the X-rays that have passed through the slit portion almost geometrically regardless of the presence or absence of the Talbot interference effect. More specifically, by setting the distances d 1 and d 2 to a value sufficiently larger than the effective wavelength of X-rays emitted from the X-ray irradiation unit 11, most of the irradiation X-rays are diffracted by the slits. Instead, a self-image of the first absorption type grating 31 can be formed behind the first absorption type grating 31. For example, when tungsten is used as the target of the radiation source and the tube voltage is 50 kV, the effective wavelength of X-ray is about 0.4 mm.
- the distances d 1 and d 2 are set to about 1 to 10 ⁇ m, the radiation image formed by the radiation that has passed through the slit portion becomes such that the effect of diffraction can be ignored, and the first absorption grating 31 can be ignored.
- the self-image of the first absorption-type grating 31 is projected almost geometrically.
- the G1 image is enlarged in proportion to the distance from the X-ray focal point 18b.
- the slits of the second absorption type grating 32 are determined so as to substantially match the pattern of the periodic intensity distribution of the G1 image at the position of the second absorption type grating 32.
- the grating pitch p 2 is determined so as to satisfy the relationship of the following formula (1).
- the distance L 2 from the first absorption type grating 31 to the second absorption type grating 32 is limited to the Talbot interference distance determined by the grating pitch of the first diffraction grating and the X-ray wavelength.
- the X-ray imaging apparatus 1 has a configuration in which the influence of the incident X-ray diffraction by the first absorption type grating 31 is small, and the G1 image is obtained almost similarly behind the first absorption type grating 31. is therefore, the distance L 2, can be set independently of the Talbot distance.
- the Talbot interference distance Z when it is assumed that X-rays are diffracted by the first absorption type grating 31 is the grating pitch p of the first absorption type grating 31. 1 , using the grating pitch p 2 of the second absorption grating 32, the X-ray wavelength (effective wavelength) ⁇ , and a positive integer m, the following expression (2).
- Expression (2) is an expression representing the Talbot interference distance when the X-ray emitted from the X-ray irradiation unit 11 is a cone beam, “Timm ⁇ Weitkamp, et al., Proc. Of SPIE, Vol. 6318, It is known from “2006 63180S-1”.
- Talbot distance Z by the following equation (4) and in the case of X-rays emitted from the X-ray irradiation unit 11 can be regarded as substantially parallel beams, a distance L 2, the value of the range that satisfies the following equation (5) Set to.
- the distance L 2 does not necessarily satisfy the expressions (3) to (5), and deviates from the expressions (3) to (5), for example, when there is no request for thinning of the photographing unit 12. Range values can also be taken.
- FIG. 5 schematically shows the configuration of the X-ray image detector 30.
- the X-ray image detector 30 uses a flat panel detector (FPD: Flat Panel Detector) based on a thin film transistor (TFT: Thin Film Transistor) panel, and converts a plurality of pixels 40 by converting X-rays into electric charges.
- FPD Flat Panel Detector
- TFT Thin Film Transistor
- a scanning circuit 42 for controlling the charge readout timing from the image receiver 41, the charges accumulated in each pixel 40 are read out, and the charges are converted into image data.
- a data transmission circuit 44 that transmits the image data to the arithmetic processing unit 22 via the I / F 25 of the console 3.
- the scanning circuit 42 and each pixel 40 are connected by a scanning line 45 for each row, and the readout circuit 43 and each pixel 40 are connected by a signal line 46 for each column.
- Each pixel 40 is a direct conversion type in which X-rays are directly converted into electric charges by a conversion layer (not shown) such as amorphous selenium and the converted electric charges are stored in a capacitor (not shown) connected to the lower electrode.
- the X-ray detection element can be configured.
- a TFT switch (not shown) is connected to each pixel 40, and the gate electrode of the TFT switch is connected to the scanning line 45, the source electrode is connected to the capacitor, and the drain electrode is connected to the signal line 46. When the TFT switch is turned on by the drive pulse from the scanning circuit 42, the charge accumulated in the capacitor is read out to the signal line 46.
- Each pixel 40 can also be configured as an indirect conversion type X-ray detection element that uses a scintillator that converts X-rays into visible light, and converts visible light converted by the scintillator into electric charge and accumulates it. It is.
- the phosphor forming the scintillator include terbium activated gadolinium oxide (Gd 2 O 2 S: Tb) and thallium activated cesium iodide (CsI: Tl).
- the X-ray image detector is not limited to an FPD based on a TFT panel, and various X-ray image detectors based on a solid-state imaging device such as a CCD sensor or a CMOS sensor can also be used.
- the readout circuit 43 includes an integration amplifier circuit, an A / D converter, a correction circuit, and an image memory.
- the integrating amplifier circuit integrates the charges output from each pixel 40 via the signal line 46, converts them into a voltage signal (image signal), and inputs it to the A / D converter.
- the A / D converter converts the input image signal into digital image data and inputs the digital image data to the correction circuit.
- the correction circuit performs offset correction, gain correction, and linearity correction on the image data, and stores the corrected image data in the image memory.
- correction processing by the correction circuit correction of X-ray exposure amount and exposure distribution (so-called shading) and pattern noise (for example, TFT) depending on the control conditions (drive frequency and readout period) of the X-ray image detector 30 are performed. Correction of the leak signal of the switch) may be included.
- the X-ray image detector 30 is arranged so that its image receiving surface is orthogonal to the optical axis C of X-rays.
- the row direction or the column direction in the array of the pixels 40 of the image receiving unit 41 is the first.
- the one absorption type grating 31 is arranged so as to be parallel to the grating pitch direction (x direction).
- a G1 image exhibiting a periodic intensity distribution reflecting the lattice structure of the first absorption type grating 31 is formed by the X-rays that have passed through the first absorption type grating 31.
- the G1 image is intensity-modulated by being superimposed on the second absorption grating 32, and the intensity-modulated G1 image is captured by the X-ray image detector 30.
- the pattern period p 1 ′ of the periodic intensity distribution of the G1 image at the position of the second absorption type grating 32 and the substantial grating pitch p 2 ′ of the second absorption type grating 32 (substantial pitch after manufacture) Is slightly different due to manufacturing errors and placement errors.
- the arrangement error means that the substantial pitch in the x direction changes due to the relative inclination and rotation of the first and second absorption gratings 31 and 32 and the distance between the two changes. I mean.
- the image contrast on the X-ray image detector 30 includes moire fringes.
- the period T in the x direction of the moire fringes is expressed by the following equation (6), where L is the distance from the X-ray focal point 18b to the X-ray image detector 30.
- the arrangement pitch P of the pixels 40 in the x direction needs to be at least not an integral multiple of the moire period T, and the following equation (7) needs to be satisfied. (Where n is a positive integer).
- the arrangement pitch P is larger than the moire period T within the range satisfying the expression (7), but the arrangement pitch P is preferably smaller than the moire period T. It is preferable to satisfy 8). This is because, in order to obtain a high-quality phase contrast image, moire fringes are preferably detected with high contrast in the phase contrast image generation process described later.
- the arrangement pitch P of the pixels 40 is a value determined in terms of design (generally about 100 ⁇ m) and is difficult to change, the magnitude relationship between the arrangement pitch P of the pixels 40 and the period T of moire fringes is shown.
- the positions of the first and second absorption gratings 31 and 32 are adjusted, and at least one of the pattern period p 1 ′ of the G1 image and the grating pitch p 2 ′ of the second absorption grating 32 is set. It is preferable to change the period T of moire fringes by changing one.
- FIG. 6 schematically shows a method of changing the period T of moire fringes.
- the change of the moire fringe period T can be performed by relatively rotating one of the first and second absorption gratings 31 and 32 about the optical axis C.
- a relative rotation mechanism 50 that rotates the second absorption grating 32 relative to the first absorption grating 31 relative to the optical axis C is provided.
- the substantial grating pitch in the x direction of the second absorption type grating 32 is changed from “p 2 ′” ⁇ “p 2 ′”. / Cos ⁇ ”, and as a result, the period T of moire fringes changes (FIG. 6A).
- the change in the period T of the moire fringes is performed by centering one of the first and second absorption gratings 31 and 32 on an axis perpendicular to the optical axis C and along the y direction.
- This can be done by relatively inclining.
- a relative inclination mechanism 51 that inclines the second absorption type grating 32 relative to the first absorption type grating 31 about the axis in the direction orthogonal to the optical axis C and along the y direction.
- the period T of the moire fringes can be changed by relatively moving one of the first and second absorption gratings 31 and 32 along the direction of the optical axis C. it can.
- the second absorption type grating 32 is changed so as to change the distance L 2 between the first absorption type grating 31 and the second absorption type grating 32.
- a relative movement mechanism 52 that relatively moves along the direction of the optical axis C is provided.
- the imaging unit 12 does not constitute a Talbot interferometer as described above, and therefore the distance L 2 can be freely set. Therefore, the distance L as in the relative movement mechanism 52.
- a mechanism for changing the period T of moire fringes by changing 2 can be suitably employed.
- the change mechanism (relative rotation mechanism 50, relative tilt mechanism 51, and relative movement mechanism 52) of the first and second absorption gratings 31 and 32 for changing the period T of the moiré fringes is a piezoelectric element or the like. It can be configured by an actuator.
- the periodic intensity distribution of the G1 image is modulated by the subject H, and the G1 image And the moire fringes due to the superposition of the second absorption type grating 32 are also modulated.
- This modulation amount is proportional to the angle of the X-ray deflected by the refraction effect by the subject H.
- the image acquired by the X-ray image detector 30 includes a periodic pattern corresponding to moire fringes, and a phase contrast image of the subject H can be generated by analyzing the image including the periodic pattern. .
- FIG. 7 shows one X-ray refracted according to the phase shift distribution ⁇ (x) of the subject H in the x direction.
- Reference numeral 55 indicates an X-ray path that goes straight when the subject H does not exist.
- the X-ray that travels along the path 55 passes through the first and second absorption gratings 31 and 32 and is an X-ray image.
- the light enters the detector 30.
- Reference numeral 56 indicates an X-ray path refracted and deflected by the subject H when the subject H exists. X-rays traveling along this path 56 are shielded by the second absorption type grating 32 after passing through the first absorption type grating 31.
- phase shift distribution ⁇ (x) of the subject H is expressed by the following formula (9), where n (x, z) is the refractive index distribution of the subject H and z is the direction in which the X-ray travels.
- the G1 image projected from the first absorptive grating 31 to the position of the second absorptive grating 32 is displaced in the x direction by an amount corresponding to the refraction angle ⁇ due to refraction of X-rays at the subject H. become.
- This displacement amount ⁇ x is approximately expressed by the following equation (10) based on the fact that the refraction angle ⁇ of X-rays is very small.
- the refraction angle ⁇ is expressed by Expression (11) using the X-ray wavelength ⁇ and the phase shift distribution ⁇ (x) of the subject H.
- the displacement amount ⁇ x of the G1 image due to the refraction of X-rays at the subject H is related to the phase shift distribution ⁇ (x) of the subject H.
- This displacement amount ⁇ x is related to the phase shift amount ⁇ of the signal of each pixel of the image data (the signal phase difference between when the subject H is present and when it is not present) as shown in the following equation (12). Yes.
- the phase shift amount ⁇ of the signal of each pixel is obtained from the equation (12), and the differential amount of the phase shift distribution ⁇ (x) is obtained using the equation (11).
- the phase shift distribution ⁇ (x) of the subject H that is, the phase contrast image of the subject H can be generated.
- the phase shift amount ⁇ is calculated using a fringe scanning method described below.
- one of the first and second absorption-type gratings 31 and 32 is translated in a stepwise manner within the plane where the grating is positioned, and the second is applied to the periodic intensity distribution of the G1 image.
- the imaging is performed while changing the phase of the periodic arrangement of the X-ray shielding portions 32b of the absorption type grating 32.
- the second absorption type grating 32 is moved by the scanning mechanism 33 (see FIG. 1), but the first absorption type grating 31 may be moved.
- Moire fringes move with the movement of the second absorption grating 32, and the translational distance in the grating pitch direction of the second absorption grating 32 is one period of the grating pitch of the second absorption grating 32 (the grating pitch).
- p 2 the translational distance in the grating pitch direction of the second absorption grating 32 is one period of the grating pitch of the second absorption grating 32 (the grating pitch).
- p 2 ie when the phase change reaches 2 ⁇
- the moire fringes return to their original positions.
- Such a change in moire fringes is captured by the X-ray image detector 30 while moving the second absorption grating 32, and a plurality of signal values are obtained for each pixel from the obtained plurality of image data.
- a phase shift amount ⁇ of the signal of each pixel is obtained by performing arithmetic processing in the arithmetic processing unit 22.
- the second absorption type grating 32 is moved in the grating pitch direction (x direction) by the scanning pitch (p 2 / M) obtained by dividing the grating pitch p 2 into M (integer of 2 or more).
- a state is shown typically.
- the initial position of the second absorption grating 32 is the same as the dark part of the G1 image at the position of the second absorption grating 32 when the subject H is not present.
- the second absorption grating 32 has been described as being moved in the grating pitch direction (x direction). However, as long as displacement in the grating pitch direction is involved, the second absorption grating 32 is shown in FIG. As described above, the second absorption type grating 32 may be moved in a direction intersecting with the grating pitch direction (x direction). By moving the second absorption type grating 32 in a direction crossing the grating pitch direction, the translation distance along the scanning direction until the translation distance in the grating pitch direction reaches the grating pitch p 2 is equal to the grating pitch p. Greater than 2 .
- the scanning pitch obtained by dividing the translation distance along the scanning direction into M pieces is also increased, and resistance to movement errors of the second absorption type grating 32 is increased.
- the refraction of the X-ray generated by passing through the subject H is only a few ⁇ rad, and the modulation of the moire fringe caused by this refraction and the phase change of the signal obtained by analyzing the moire fringe by the above-described fringe scanning method are also slight. is there. In the case of measuring such a slight change, it is possible to improve the detection accuracy of the phase information of the subject H by increasing the resistance against the movement error of the second absorption grating 32.
- I k (x) is expressed by the following equation (13).
- x is a coordinate in the x direction of each pixel
- a 0 is the intensity of the incident X-ray
- An is a value corresponding to the contrast of the signal (where n is a positive integer).
- ⁇ (x) represents the refraction angle ⁇ as a function of the pixel coordinate x.
- arg [] means extraction of the declination, and corresponds to the phase shift amount ⁇ of the signal of each pixel. Therefore, the refraction angle ⁇ (x) is obtained by calculating the phase shift amount ⁇ of the signal of each pixel from the M signal values obtained for each pixel based on the equation (15).
- FIG. 10 shows the signal waveform of one pixel that changes with the fringe scanning.
- the M signal values obtained for each pixel periodically change with the period of the grating pitch p 2 with respect to the position k of the second absorption type grating 32.
- a broken line in FIG. 10 indicates a signal waveform when the subject H does not exist, and a solid line in FIG. 10 indicates a signal waveform when the subject H exists.
- the phase difference between the two waveforms corresponds to the phase shift amount ⁇ of the signal of each pixel.
- the refraction angle ⁇ (x) corresponds to the differentiation of the phase shift distribution ⁇ (x) as shown in the above equation (11), the refraction angle ⁇ (x) is integrated along the x axis. A phase shift distribution ⁇ (x) is obtained.
- the y-coordinate regarding the y-direction of the pixel is not taken into consideration. However, by performing the same calculation for each y-coordinate, a two-dimensional phase shift distribution ⁇ (x, y) is obtained. The above calculation is performed by the calculation processing unit 22, and the calculation processing unit 22 stores the phase shift distribution ⁇ (x, y) in the storage unit 23 as a phase contrast image.
- FIG. 11 shows another example of a method for generating a phase contrast image in the X-ray imaging apparatus 1.
- a plurality of pixels arranged in a direction intersecting with the moire fringe are analyzed as a unit, and the phase shift amount ⁇ of the signal of each pixel is calculated from one image data.
- the first and second absorption type gratings 31 and 32 are arranged so as to be relatively rotated by an angle ⁇ about the optical axis C, and the G1 image and the second absorption type grating are arranged. 32 is relatively rotated by an angle ⁇ , and moire fringes having periodicity in the y direction are generated. Therefore, the analysis is performed with a plurality of pixels arranged in the y direction intersecting the moire fringes as one unit U. In the example shown in FIG. 11, five pixels arranged in the y direction are defined as one unit U.
- the G1 image is displaced in the x direction by an amount corresponding to the refraction angle ⁇ due to the refraction of X-rays at the subject H, and the moire fringes are displaced in the y direction as the G1 image is displaced in the x direction. Will do.
- the phase of the signal waveform obtained by interpolating the signal value of the pixel group constituting the unit changes for each unit.
- the phase difference between the waveform of the signal waveform (FIG. 12A) when the subject H is not present and the signal waveform (FIG. 12B) when the subject H is present is the phase of the pixel signal included in the unit. This corresponds to the displacement amount ⁇ .
- the phase shift amount ⁇ of the signal of each pixel can be obtained by performing the above analysis for each unit while shifting the unit of the pixel group to be analyzed, for example, by one pixel in the y direction. That is, the phase shift amount ⁇ of the k-th pixel 40 of the signal at the row of the y direction of pixels 40, the signal value of the k-th pixel 40 as I k, [I k, I k + 1, I k + 2, I k + 3, 5 signal values of I k + 4 ] and 5 signal values of [I k + 1 , I k + 2 , I k + 3 , I k + 4 , I k + 5 ] are used as the phase shift amount ⁇ of the signal of the (k + 1) th pixel 40.
- the above analysis can be performed for each unit while shifting the unit of the pixel group by a plurality of pixels in the y direction within a range of 5 pixels or less as one unit.
- the phase shift amount ⁇ of the signal of each of the kth and k + 1th pixels 40 uses five signal values of [I k , I k + 1 , I k + 2 , I k + 3 , I k + 4 ].
- K + 2 and k + 3 pixels 40 can be obtained by using five signal values of [I k + 2 , I k + 3 , I k + 4 , I k + 5 , I k + 6 ]. .
- the refraction angle ⁇ is obtained from the phase shift amount ⁇ of the signal of each pixel using the equation (12), and the differential amount of the phase shift distribution ⁇ (x) is obtained using the equation (11), and this is integrated with respect to x.
- the phase shift distribution ⁇ (x) of the subject H that is, the phase contrast image of the subject H is generated.
- the number of pixels as a unit is preferably the number of pixels over which at least one period of the moire period T in the y direction is arranged.
- the moire period T in the y direction is set to be approximately M times the arrangement pitch P of the pixels 40 in the y direction (M is an integer), and the M pixels 40 are taken as one unit, the pixel 40
- the signal values of the k-th pixel 40 in the y-direction array are I k
- the M signal values of I k to I k + M ⁇ 1 are the first and second absorption gratings 31 in the fringe scanning method described above.
- 32 is equivalent to M signal values acquired for the kth pixel 40 when the grid pitch is moved in the grid pitch direction at a scan pitch obtained by dividing the grid pitch into M pieces. .
- FIG. 13 shows a modification of the analysis method of FIG.
- the grating pitch p 2 of the second absorption type grating 32 is different from the pitch p 1 ′ of the G1 image, and moire fringes having periodicity in the x direction are generated.
- one of the first and second absorption gratings 31 and 32 is placed in the direction of the optical axis C. May be moved relative to each other, or the grating pitch of each of the first and second absorption gratings 31 and 32 may be adjusted.
- the above analysis is performed with a plurality of pixels arranged in the x direction intersecting the moire fringes as one unit U.
- four pixels arranged in the x direction are set as one unit U.
- the above analysis is performed.
- the relationship to be satisfied between the period T of moire fringes in the x direction and the pitch P of the pixels 40 in the x direction is expressed by the following equation (18).
- FIG. 14 shows another modification of the analysis method of FIG.
- the grating pitch p 2 of the second absorption grating 32 is different from the pitch p 1 ′ of the G1 image, and the second absorption grating 32 rotates relative to the G1 image.
- Moire fringes having periodicity are generated in the direction intersecting the x direction and the y direction.
- the analysis can be performed with a plurality of pixels of 3 pixels or more arranged in the x direction as one unit U (FIG. 14A), or a plurality of pixels of 3 pixels or more arranged in the y direction can be analyzed. Analysis can also be performed as one unit U (FIG. 14B).
- FIG. 15 shows another modification of the analysis method of FIG.
- the pattern period direction (x direction) of the periodic intensity distribution of the G1 image and the row direction or the column direction in the array of the pixels 40 in the X-ray image detector 30 match.
- the first absorption type grating 31 and the X-ray image detector 30 are arranged so as to rotate relative to each other about the optical axis C, so that the periodic intensity distribution of the G1 image is obtained. Both the row direction and the column direction in the array of the pixels 40 intersect with the pattern periodic direction (x direction).
- the moire fringe is resolved with a plurality of pixels of three or more pixels arranged in the direction intersecting the moire fringe as one unit U, the pixels included in the unit are determined for each unit.
- the amount of phase shift ⁇ of the signal can be calculated.
- a phase contrast image can be generated from one periodic pattern image, and thus only one imaging is required. Therefore, the first absorption type grating 31 or the second between multiple imagings. Therefore, the movement of the absorption type grating 32 and the scanning mechanism 33 that requires high accuracy are not required. Therefore, it is possible to improve the shooting workflow and simplify the apparatus. In addition, it is possible to eliminate the deterioration in image quality caused by the movement of the subject between each photographing.
- FIG. 16 shows another example of a method for generating a phase contrast image in the X-ray imaging apparatus 1.
- a periodic pattern of an image is analyzed using Fourier transform and inverse Fourier transform to generate a phase contrast image.
- the periodic pattern of the image corresponding to the moire fringes formed by superimposing the G1 image and the second absorption type grating 32 can be expressed by the following equation (19), and the equation (19) is expressed by the following equation (20). Can be rewritten.
- a (x, y) represents the background
- b (x, y) represents the amplitude of the spatial frequency component corresponding to the basic period of the periodic pattern
- (f 0x, f 0y ) represents the period. Represents the basic period of the pattern.
- c (x, y) is represented by the following formula (21).
- equation (20) becomes the following equation (22) by Fourier transform.
- F (f x , f y), A (f x, f y), C (f x, f y) respectively f (x, y), a (x, y), c It is a two-dimensional Fourier transform for (x, y).
- the spatial frequency spectrum of the image has at least A (f x , f y ) as shown in FIG. a peak derived from, C (f x, f y ) and C * (f x, f y ) 3 peaks and the peak of the spatial frequency component corresponding to the fundamental period of the periodic pattern from the results across this .
- a (f x, f y) peak derived from the origin also, C (f x, f y ) and C * (f x, f y ) peak derived from the ( ⁇ f 0x, ⁇ f 0y ) It occurs at the position of (combined same order).
- the refraction angle ⁇ (x, y) In order to obtain the refraction angle ⁇ (x, y) from the spatial frequency spectrum of the image, a region including the peak frequency of the spatial frequency component corresponding to the basic period of the periodic pattern is cut out so that the peak frequency overlaps the origin of the frequency space. Move the clipped area and perform inverse Fourier transform. Then, the refraction angle ⁇ (x, y) can be obtained from the complex number information obtained by the inverse Fourier transform.
- the method for generating the phase contrast image from the refraction angle ⁇ (x, y) is the same as the above-described fringe scanning method.
- a phase contrast image can be generated from one periodic pattern image, and thus only one imaging is required. Therefore, the first absorption type grating 31 or the second between multiple imagings. Therefore, the movement of the absorption type grating 32 and the scanning mechanism 33 that requires high accuracy are not required. Therefore, it is possible to improve the shooting workflow and simplify the apparatus. In addition, it is possible to eliminate the deterioration in image quality caused by the movement of the subject between each photographing.
- the refraction angle ⁇ with respect to the x direction which is the lattice pitch direction of the first absorption type grating 31, that is, the differential of the phase shift distribution ⁇ is obtained, and the differential of the phase shift distribution ⁇ is obtained.
- the edge of the subject H that intersects the grating pitch direction of the first absorption type grating 31 is depicted, and in particular, substantially perpendicular to the grating pitch direction of the first absorption type grating 31.
- the edge of the subject H is clearly depicted. That is, the arrangement of the subject H is restricted by the lattice pitch direction of the first absorption-type lattice 31.
- FIG. 17 shows the arrangement of the arm member 61 in relation to the first absorption type lattice 31.
- the X-ray irradiation unit 11, the imaging unit 12, and the subject table 15 are all supported by the arm member 61 of the stand 13, and X-ray irradiation is performed from above in the vertical direction (z direction) in which the arm member 61 extends.
- the unit 11, the subject table 15, and the imaging unit 12 are arranged in this order.
- the imaging unit 12 having the first absorption type grating 31 is arranged so that the edge in the extending direction (y direction) of the X-ray shielding part 31 b of the first absorption type grating 31 follows the arm member 61. It is attached to the member 61.
- the arm member 61 places the first absorption grating 31 in the grating pitch direction (x in the plane A including the placement surface of the subject table 15 on which the subject H is placed, that is, the plane A extending to the arrangement position of the subject H.
- the arm member 61 deviates from a region where the mounting surface of the subject table 15 is extended in the lattice pitch direction (x direction) of the first absorption type grating 31, and the mounting surface of the subject table 15 is moved to the first surface.
- the absorption grating 31 extends in the vertical direction through a region extending in the extending direction (y direction) of the X-ray shielding portion 31b.
- the arm member 61 has the mounting surface of the subject table 15. Is removed from the region extending in the lattice pitch direction of the second absorption type grating 32, and passes through the region where the mounting surface of the subject table 15 is extended in the extending direction of the X-ray shielding portion 32 b of the second absorption type grating 32. Extending in the vertical direction.
- FIG. 18 shows an example of the arrangement of the subject H.
- the arm member 61 is not positioned at the tip of the subject table 15 with respect to the grating pitch direction (x direction) of the first absorption grating 31. Therefore, a relatively long subject H such as an arm or a leg can be arranged along the lattice pitch direction of the first absorption type lattice 31.
- a relatively long subject H such as an arm or a leg can be arranged along the lattice pitch direction of the first absorption type lattice 31.
- the boundary between the joint fluid filling the joint space and the cartilage covering each of the femur B1 and the tibia B2 constituting the knee joint is the first absorption.
- the edge of the cartilage is clearly depicted in the phase contrast image.
- the X-ray irradiation unit 11, the imaging unit 12, and the subject table 15 are supported by the arm member 61 in a cantilever shape, and the arm member 61 is disposed so as to pass through the above-described region A2.
- the arm member 61 extending out of the area A1 and extending in the vertical direction can be disposed close to the X-ray irradiation unit 11, the imaging unit 12, and the subject table 15. Thereby, the beam length can be shortened, and the tilt and vibration of the X-ray irradiation unit 11, the imaging unit 12, and the subject table 15 can be prevented or suppressed.
- the refraction of the X-ray generated by passing through the subject H is only a few ⁇ rad, and the modulation of the moire fringe caused by this refraction and the phase change of the signal obtained by analyzing the moire fringe by the above-described fringe scanning method are also slight. is there.
- the relative position shift of the X-ray focal point 18b and the first and second absorption gratings 31 and 32 affects the detection accuracy of the phase information of the subject H.
- the relative position of the X-ray focal point 18 b and the first and second absorption gratings 31 and 32 can be prevented from shifting. Therefore, the detection accuracy of the phase information of the subject H can be increased.
- the subject table 15 absorbs or relaxes shocks, vibrations, and the like. It is attached to the arm member 61 via FIG. Accordingly, it is possible to prevent or suppress an impact when the subject H is placed on the subject table 15, vibration due to a movement (body movement) of the subject H during or during photographing, and the like, from being transmitted to the arm member 61. be able to.
- the relative position shift of the X-ray focal point 18b and the first and second absorption gratings 31 and 32 can be prevented or suppressed, and the detection accuracy of the phase information of the subject H can be improved. it can.
- a material of the buffer member 15a for example, hard rubber or various resins can be applied, but the material of the buffer member 15a is not limited thereto.
- the arm member 61 is not obstructed and the subject H is appropriately arranged.
- a clear phase contrast image can be obtained.
- the irradiated X-rays have high spatial coherence. It is not required and a general X-ray source used in the medical field can be used.
- the distance L 2 from the first absorption type grating 31 to the second absorption type grating 32 can be set to an arbitrary value, and the distance L 2 is set smaller than the minimum Talbot interference distance in the Talbot interferometer. Therefore, the photographing unit 12 can be downsized (thinned).
- the first grating is not limited to the absorption type grating but may be a phase type grating.
- the Talbot interference distance Z is expressed by the following expression (23)
- the pattern period p 1 ′ of the Talbot interference image is expressed by the following expression (24).
- the Talbot interference distance Z is expressed by the following expression (25)
- the pattern period p 1 ′ of the Talbot interference image is expressed by the following expression (26).
- the phase shift distribution ⁇ is obtained by integrating the differential amount of the phase shift distribution ⁇ obtained from the refraction angle ⁇ .
- the differential amount of the refraction angle ⁇ and the phase shift distribution ⁇ is also related to the X-ray phase change by the subject. Therefore, an image of the refraction angle ⁇ and an image of the differential amount of the phase shift are also included in the phase contrast image.
- phase contrast image generation processing may be performed on the moire fringes obtained by photographing (pre-photographing) in the absence of a subject, and the phase contrast image may be obtained.
- This phase contrast image reflects, for example, phase unevenness (initial phase shift) caused by non-uniformity of the first and second absorption gratings 31 and 32.
- FIG. 19 shows a configuration of a modified example of the X-ray imaging apparatus 1.
- the X-ray imaging apparatus 1 when the distance from the X-ray irradiation unit 11 to the X-ray image detector 30 is set to a distance (1 m to 2 m) as set in a general hospital imaging room,
- the blur of the G1 image due to the focal size of the X-ray focal point 18b (generally about 0.1 mm to 1 mm) is affected, and there is a possibility that the image quality of the phase contrast image is degraded. Therefore, it is conceivable to install a pinhole immediately after the X-ray focal point 18b to effectively reduce the focal spot size. However, if the aperture area of the pinhole is reduced to reduce the effective focal spot size, the X-ray focal point is reduced. Strength will fall. In this example, in order to solve this problem, the multi slit 35 is disposed immediately after the X-ray focal point 18b.
- the multi slit 35 is an absorption type grating (third absorption type grating) having the same configuration as that of the first and second absorption type gratings 31 and 32, and a plurality of X-ray shielding portions extending in one direction are provided in the first slit.
- the first and second absorption type gratings 31 and 32 are periodically arranged in the same direction (x direction) as the X-ray shielding portions 31b and 32b.
- the purpose of the multi-slit 35 is to form small focal light sources (dispersed light sources) arranged at a predetermined pitch in the x direction by partially shielding the radiation emitted from the X-ray focal point 18b.
- the lattice pitch p 3 of the multi-slit 35 needs to be set so as to satisfy the following equation (27), where L 3 is the distance from the multi-slit 35 to the first absorption-type lattice 31.
- Expression (27) indicates that the projection image (G1 image) of the X-rays emitted from the small focus light sources dispersedly formed by the multi-slit 35 by the first absorption type grating 31 is the position of the second absorption type grating 32. This is a geometric condition for matching (overlapping).
- the grating pitch p2 of the second absorption grating 32 is determined so as to satisfy the relationship of the following equation (28).
- the G1 images based on the plurality of point light sources formed by the multi-slit 35 are superimposed, so that the image quality of the phase contrast image can be improved without reducing the X-ray intensity. it can.
- any of the above-described analysis methods 1 to 3 can be applied.
- the multi-slit 35 When accompanied by rotation about the optical axis C, the multi-slit 35 also rotates together with the first absorption grating 31 so that the grating pitch direction coincides with the grating pitch direction of the first absorption grating 31. It is preferred that Further, in the analysis method 1 described above, when changing the relative positional relationship between the G1 image and the second absorption grating 32, the multi-slit 35 can be moved in a direction intersecting the X-ray shielding portion. .
- FIG. 20 shows the configuration of another example of a radiation imaging apparatus for explaining an embodiment of the present invention. Elements common to the X-ray imaging apparatus 1 shown in FIG. 1 are denoted by common reference numerals, and description thereof is omitted or simplified.
- An X-ray imaging apparatus 101 shown in FIG. 20 is different from the X-ray imaging apparatus 1 shown in FIG. 1 in that the first absorption type grating 31 is disposed between the X-ray irradiation unit 11 and the subject table 15. ing.
- the first absorption type lattice 31 is held by the holding member 34 and is attached to the arm member 61 via the holding member 34. Since the holding member 34 is supported by the arm member 61 in a cantilever shape, it is preferable that the holding member 34 has high rigidity. For example, a member having higher rigidity than the substrate 31a of the first absorption type lattice 31 is used. preferable. Thereby, the relative position shift of the X-ray focal point 18b and the first and second absorption gratings 31 and 32 can be prevented or suppressed, and the detection accuracy of the phase information of the subject H can be improved.
- the subject H is disposed between the first absorption type grating 31 and the second absorption type grating 32, but the first object formed at the position of the second absorption type grating 32.
- the G1 image of the absorption type grating 31 is modulated by the subject H.
- the G1 image is intensity-modulated by superposition with the second absorption grating 32, and the intensity-modulated G1 image is captured by the X-ray image detector 30. Is done. Therefore, the X-ray imaging apparatus 101 can also obtain a phase contrast image of the subject H on the same principle as the analysis methods 1 to 3 described in the X-ray imaging apparatus 1 shown in FIG.
- the subject H is irradiated with X-rays whose dose is almost halved by shielding with the first absorption type grating 31. Therefore, the exposure amount of the subject H is shown in FIG. It can be reduced to about half that of the X-ray imaging apparatus 1 shown.
- the first grating is not limited to the absorption grating but may be a phase grating.
- the above-described multi slit 35 (see FIG. 19) can be provided.
- FIG. 21 shows the configuration of another example of a radiation imaging apparatus for explaining the embodiment of the present invention. Elements common to the X-ray imaging apparatus 1 shown in FIG. 1 are denoted by common reference numerals, and description thereof is omitted or simplified.
- the imaging unit 212 is roughly constituted by the first absorption type grating 31 and the X-ray image detector 230, and the second absorption type grating 32 is omitted. 1 is different from the X-ray imaging apparatus 1 shown in FIG.
- the X-ray image detector 230 includes an image receiving unit 41 in which a plurality of pixels 40 that convert X-rays into electric charges and store them are two-dimensionally arranged, read out the electric charges accumulated in each pixel 40, and read them out as image data. To be sent to the console 3.
- the plurality of pixels 40 are arranged at an arrangement pitch capable of resolving the periodic intensity distribution of the G1 image formed on the image receiving surface of the X-ray image detector 230.
- the arrangement pitch P of the pixels 40 is set to a pitch of 1/2 or less, preferably 1/5 or less of the pattern period p 1 ′ of the periodic intensity distribution of the G1 image, which is generally several ⁇ m.
- An X-ray image detector in which a plurality of pixels are arranged in such a small arrangement pitch is a CCD sensor or a read circuit that is formed on a semiconductor substrate made of single crystal silicon or the like, and a readout circuit that reads out the electric charge accumulated in each pixel.
- a solid-state imaging device such as a CMOS sensor can be used as a base.
- the one configured based on the TFT panel may be used.
- the G1 image is formed on the X-ray image detector 230.
- the subject H is arranged on the subject table 15 arranged between the X-ray irradiation unit 11 and the imaging unit 212, more specifically between the X-ray irradiation unit 11 and the first absorption type grating 31.
- the periodic intensity distribution of the G1 image is modulated by the subject H.
- the image acquired by capturing the G1 image by the X-ray image detector 230 includes a periodic pattern corresponding to the periodic intensity distribution of the G1 image. By analyzing this periodic pattern, the phase contrast of the subject H is analyzed. An image can be generated.
- the analysis of the periodic pattern of the image can be performed, for example, by the above-described fringe scanning method.
- the G1 image projected from the first absorption type grating 31 to the position of the X-ray image detector 230 is displaced in the x direction by an amount corresponding to the refraction angle ⁇ due to refraction of X-rays at the subject H. It will be.
- This displacement amount ⁇ x is approximately expressed by the following equation (29) based on the fact that the X-ray refraction angle ⁇ is very small.
- L 4 indicates the distance from the first absorption type grating 31 to the X-ray image detector 230.
- the refraction angle ⁇ is expressed by Expression (30) using the X-ray wavelength ⁇ and the phase shift distribution ⁇ (x) of the subject H.
- the displacement amount ⁇ x of the G1 image due to the refraction of X-rays at the subject H is related to the phase shift distribution ⁇ (x) of the subject H.
- the displacement amount ⁇ x is related to the phase shift amount ⁇ of the signal of each pixel of the image data as in the following equation (31).
- the phase shift amount ⁇ of the signal of each pixel is obtained from the equation (31), and the differential amount of the phase shift distribution ⁇ (x) is obtained using the equation (30).
- the phase shift distribution ⁇ (x) of the subject H that is, the phase contrast image of the subject H can be generated.
- the phase shift amount ⁇ is calculated using a fringe scanning method.
- the first absorption type grating 31 is translated in a stepwise manner relative to the X-ray image detector 230 in the grating pitch direction (x direction) of the grating, and the period of the pixel 40 with respect to the periodic intensity distribution of the G1 image. Shooting while relatively changing the phase of the target array.
- the movement of the first absorption type grating 31 can be performed by the scanning mechanism 33.
- the G1 image moves, and the translation distance (the amount of movement in the x direction) is one period of the grating period of the first absorption type grating 31 (grating pitch p 1 ). (Ie, when the phase change reaches 2 ⁇ ), the G1 image returns to its original position.
- Such a change in the G1 image is picked up by the X-ray image detector 230 while moving the first absorption type grating 31 by a distance of 1 / integer of the grating pitch p 1 , and a plurality of obtained image data
- a plurality of signal values are obtained from each pixel, and the arithmetic processing unit 22 performs arithmetic processing to obtain a phase shift amount ⁇ of the signal of each pixel.
- the refraction angle ⁇ is obtained from the phase shift amount ⁇ of the signal of each pixel using the equation (31), and the differential amount of the phase shift distribution ⁇ (x) is obtained using the equation (30).
- the phase shift distribution ⁇ (x) of the subject H ie, the phase contrast image of the subject H is generated.
- FIG. 22 shows another example of a method for generating a phase contrast image in the X-ray imaging apparatus 201.
- a plurality of pixels arranged in the lattice pitch direction (x direction) of the first absorption type lattice 31 is defined as one unit, and the signal values I of the plurality of pixels constituting the unit are interpolated for each unit.
- signal values of a plurality of pixels are interpolated by a sine curve, and at least three points are sufficient for interpolation by the sine curve, and therefore three adjacent pixels are used as a unit.
- the G1 image is displaced in the x direction by an amount corresponding to the refraction angle ⁇ due to refraction of X-rays at the subject H.
- the phase of the signal waveform formed by interpolating the signal values I of a plurality of pixels constituting the unit changes for each unit.
- the phase difference between the waveform of the signal waveform (FIG. 22A) when the subject H is not present and the signal waveform (FIG. 22B) when the subject H is present is the phase of the signal of the pixel included in the unit. This corresponds to the displacement amount ⁇ .
- the refraction angle ⁇ is obtained from the phase shift amount ⁇ of the signal of each pixel using the equation (31) and the differential amount of the phase shift distribution ⁇ (x) is obtained using the equation (30), and this is integrated with respect to x.
- the phase shift distribution ⁇ (x) of the subject H that is, the phase contrast image of the subject H is generated.
- the first absorption-type grating is assumed that the grating pitch direction (x-direction) of the first absorption-type grating 31 coincides with the row direction or the column direction in the arrangement of the pixels 40 in the X-ray image detector 230.
- the description has been made assuming that three pixels arranged in the lattice pitch direction of 31, that is, the pattern periodic direction of the periodic intensity distribution of the G1 image, are taken as one unit, the direction intersecting the periodic intensity distribution pattern of the G1 image If the periodic intensity distribution of the G1 image is resolved with a plurality of pixels of three or more arranged in a unit as a unit, the phase shift amount ⁇ of the signal of the pixel included in the unit can be calculated for each unit.
- the first absorption grating 31 and the X-ray image detector 230 are arranged such that the row direction and the column direction in the arrangement of the pixels 40 intersect with the pattern period direction of the periodic intensity distribution of the G1 image.
- the optical axis C may be relatively rotated around the optical axis C.
- the X-ray imaging apparatus 201 can also generate a phase contrast image by analyzing a periodic pattern of an image using Fourier transform and inverse Fourier transform.
- the periodic pattern of the image corresponds to moire fringes formed by superimposing the G1 image and the second absorption type grating 32. In the X-ray imaging apparatus 201, this corresponds to the periodic intensity distribution of the G1 image.
- the periodic intensity distribution of the G1 image is detected using a detector having a pixel pitch smaller than the period of the periodic intensity distribution of the G1 image, and this is analyzed to obtain phase information. Since the pixel pitch is small, the spatial resolution is excellent. Further, since the second absorption type grating 32 is not interposed, the detection accuracy of the phase information can be improved.
- the first grating is not limited to the absorption grating but may be a phase grating.
- the X-ray irradiation unit 11 can be provided with the multi slit 35 (see FIG. 19) described above.
- the multi-slit lattice pitch p 3 is set to satisfy the following equation (32), where L 3 is the distance from the multi-slit to the first absorption type lattice 31.
- Expression (32) indicates that the projection image (G1 image) of the X-rays emitted from the small-focus light sources dispersedly formed by the multi-slits by the first absorption type grating 31 coincides with the position of the X-ray image detector 230. It is a geometrical condition for doing (overlapping).
- the first absorption type grating 31 can also be disposed between the X-ray irradiation unit 11 and the subject table 15.
- FIG. 23 shows a modification of the X-ray imaging apparatus of FIG.
- the plurality of pixels 40 of the X-ray image detector 230A have a pattern period of the periodic intensity distribution of the G1 image formed on the image receiving surface of the X-ray image detector 230A. They are arranged at an arrangement pitch that causes moire in the relationship. Specifically, the arrangement pitch P of the pixels 40 is set to be approximately the same as the pattern period of the periodic intensity distribution of the G1 image, which is generally several ⁇ m.
- the arrangement pitch P of the pixels 40 is a value determined in terms of design and is difficult to change, when generating moire, the arrangement pitch P of the pixels 40 and the pattern period p of the periodic intensity distribution of the G1 image.
- a mechanism for changing the pattern period of the periodic intensity distribution of the G1 image a mechanism similar to the above-described relative rotation mechanism 50, relative tilt mechanism 51, and relative movement mechanism 52 (all refer to FIG. 6) is used. it can.
- the period T in the x direction of moire generated in the image is expressed by the following equation (33).
- moire generated in an image acquired by the X-ray image detector 230A is modulated by the subject H.
- This modulation amount is proportional to the angle of the X-ray deflected by the refraction effect by the subject H. Therefore, a phase contrast image of the subject H can be generated by analyzing this moire.
- the analysis of the periodic pattern of the image can be performed, for example, by the above-described fringe scanning method.
- the G1 image projected from the first absorption type grating 31 to the position of the X-ray image detector 230A is displaced in the x direction by an amount corresponding to the refraction angle ⁇ due to refraction of X-rays at the subject H. It will be.
- This displacement amount ⁇ x is related to the phase shift distribution ⁇ (x) of the subject H, as is apparent from the above equations (29) and (30).
- the moire is also displaced in the x direction.
- the displacement amount ⁇ x of the G1 image reaches the period p 1 ′, the moire returns to the original state. Is expressed by the following equation (34) using the displacement amount ⁇ x of the G1 image, where T is the period of the moire in the x direction.
- This displacement amount ⁇ X is related to the phase shift amount ⁇ of the signal of each pixel of the image data as shown in the following equation (35).
- the refraction angle ⁇ is obtained from the equation (31), and the differential amount of the phase shift distribution ⁇ (x) is obtained using the equation (30).
- the phase shift distribution ⁇ (x) of the subject H that is, the phase contrast image of the subject H can be generated.
- the phase shift amount ⁇ is calculated using a fringe scanning method.
- the first absorption type grating 31 is translated stepwise in the grating pitch direction (x direction) of the grating with respect to the X-ray image detector 230A, and the period of the pixel 40 with respect to the periodic intensity distribution of the G1 image. Shooting while relatively changing the phase of the target array.
- the movement of the first absorption type grating 31 can be performed by the scanning mechanism 33.
- the moire As the first absorption type grating 31 moves, the moire also moves, and the translation distance (amount of movement in the x direction) reaches one period (grating pitch p 1 ) of the grating period of the first absorption type grating 31. Then (ie, when the phase change reaches 2 ⁇ ), the moire returns to the original state.
- the phase shift amount ⁇ of the signal of each pixel is obtained by obtaining and performing arithmetic processing in the arithmetic processing unit 22.
- the refraction angle ⁇ is obtained from the phase shift amount ⁇ of the signal of each pixel using the equation (31), and the differential amount of the phase shift distribution ⁇ (x) is obtained using the equation (30).
- the phase shift distribution ⁇ (x) of the subject H ie, the phase contrast image of the subject H is generated.
- the moire moves as a whole with the relative movement between the first absorption grating 31 and the X-ray image detector 230A. It is applicable even if it is longer than that.
- FIG. 24 shows another example of a method for generating a phase contrast image in the X-ray imaging apparatus 201A.
- a plurality of pixels arranged in the lattice pitch direction (x direction) of the first absorption type lattice 31 is used as a unit, and the signal value I of the plurality of pixels constituting the unit is interpolated for each unit.
- signal values of a plurality of pixels are interpolated by a sine curve, and at least three points are sufficient for interpolation by the sine curve, and therefore, three adjacent pixels are used as a unit.
- the signal values I of a plurality of pixels constituting the unit are interpolated for each unit.
- the period of the signal waveform is a moire period T.
- the G1 image is displaced in the x direction by an amount corresponding to the refraction angle ⁇ due to refraction of X-rays at the subject H.
- the moire is also displaced by ⁇ X in the x direction, and the phase of the signal waveform changes.
- the phase difference between the waveform of the signal waveform (FIG. 24A) when the subject H is not present and the signal waveform (FIG. 24B) when the subject H is present is the phase of the signal of the pixel included in the unit. This corresponds to the displacement amount ⁇ .
- the refraction angle ⁇ is obtained from the phase shift amount ⁇ of the signal of each pixel using the equation (31) and the differential amount of the phase shift distribution ⁇ (x) is obtained using the equation (30), and this is integrated with respect to x.
- the phase shift distribution ⁇ (x) of the subject H that is, the phase contrast image of the subject H is generated.
- the first absorption-type grating is assumed that the grating pitch direction (x-direction) of the first absorption-type grating 31 coincides with the row direction or the column direction in the arrangement of the pixels 40 in the X-ray image detector 230A.
- the description has been made assuming that the three pixels arranged in the lattice pitch direction of 31, that is, the pattern period direction of the periodic intensity distribution of the G1 image, are taken as one unit, with respect to the pattern period direction of the periodic intensity distribution of the G1 image,
- the first absorption-type grating 31 and the X-ray image detector 230A are arranged so as to rotate relatively around the optical axis C so that both the row direction and the column direction in the arrangement of the pixels 40 intersect. May be.
- the X-ray imaging apparatus 201A can also generate a phase contrast image by analyzing the periodic pattern of an image using Fourier transform and inverse Fourier transform.
- the periodic pattern of the image corresponds to the periodic intensity distribution of the G1 image in the X-ray imaging apparatus 201 shown in FIG. 21, but the periodic pattern of the G1 image in the X-ray imaging apparatus 201A. This corresponds to moire caused by interference between the intensity distribution and the periodic arrangement of the pixels 40 of the X-ray image detector 230A.
- the interference between the pattern period p 1 ′ of the G1 image and the pixel pitch P of the X-ray image detector 230A causes moire in the image acquired by the X-ray image detector 230A. Then, a phase contrast image is generated based on the moire modulation caused by the subject H.
- the S / N tends to decrease as the pixels in the X-ray image detector become smaller. Therefore, the pixel arrangement pitch in the X-ray image detector becomes smaller to detect the periodic intensity distribution of the fine G1 image. Therefore, it is possible to secure the S / N and improve the detection accuracy of the phase information.
- FIG. 25 shows the configuration of another example of a radiation imaging apparatus for explaining the embodiment of the present invention. Note that elements common to the above-described X-ray imaging apparatuses 1, 101, and 201 are denoted by common reference numerals, and description thereof is omitted or simplified.
- An X-ray imaging apparatus 301 shown in FIG. 25 includes an arm member that supports the X-ray irradiation unit 11, the first and second absorption gratings 31 and 32, the X-ray image detector 30, and the subject table 15.
- an arm member that supports the X-ray irradiation unit 11, the first and second absorption gratings 31 and 32, the X-ray image detector 30, and the subject table 15.
- first support member 61
- first and second absorption gratings 31 and 32, X-ray image detector 30, and arm member (second support member) 361 that supports subject table 15. Is different from the X-ray imaging apparatus 1 shown in FIG.
- the arm member 361 for supporting the subject table 15 and the imaging unit 12 positioned on the lower side in the vertical direction (downstream of the subject table 15 in the X-ray traveling direction along the optical axis C) has a first absorption. Since there is no influence when the subject H is arranged on the placement surface of the subject table 15 along the lattice pitch direction (x direction) of the mold lattice 31, there is no particular limitation on the arrangement, but the X-ray imaging apparatus 301 is not limited.
- the arm member 361 includes the first and second absorption gratings 31, 32 and the arm member 61 in the extending direction (y direction) of the X-ray shielding part 31 b in the first absorption grating 31.
- the X-ray image detector 30 and the subject table 15 are arranged so as to be sandwiched therebetween. That is, the arm member 361 extends the first absorption type lattice 31 in the lattice pitch direction (x direction) on the opposite side of the first absorption type lattice 31 from the arm member 61 in the same manner as the arm member 61.
- the first absorption type grating 31 is provided so as to extend in the vertical direction through a region extending outside the region and extending in the extending direction (y direction) of the X-ray shielding portion 31b.
- the subject table 15 includes a buffer member 15b that absorbs or relaxes shock, vibration, and the like.
- the arm member 361 is attached.
- the X-ray imaging apparatus 301 the X-ray irradiation unit 11, the first and second absorption gratings 31 and 32, the X-ray image detector 30, and the subject table 15 are supported by a plurality of support members ( By dividing the arm member 61 and the arm member 361), the load acting on each support member is reduced, and deformation of each support member is prevented or suppressed. Thereby, the shift of the relative positions of the X-ray focal point 18b and the first and second absorption gratings 31 and 32 due to the deformation of the support member can be prevented or suppressed, and the detection accuracy of the phase information of the subject H can be improved. Can be increased.
- the arm member 361 includes the first and second absorption gratings 31, 32 and the arm member 61 in the extending direction (y direction) of the X-ray shielding portion 31 b in the first absorption grating 31.
- the X-ray image detector 30 and the object table 15 are arranged to be sandwiched between them.
- the movement in the y direction is performed. It can be regulated and moved reliably in the x direction.
- the first grating is not limited to the absorption grating but may be a phase grating.
- the X-ray irradiation unit 11 can be provided with the multi-slit 35 (see FIG. 19) described above.
- FIG. 26 shows a modification of the X-ray imaging apparatus 301 of FIG.
- the first absorption type grating 31 is disposed between the X-ray irradiation unit 11 and the subject table 15 like the X-ray imaging apparatus 101 shown in FIG.
- the arm member 361 is different from the X-ray imaging apparatus 301 shown in FIG. 25 in that the arm member 361 supports the second absorption type grating 32, the X-ray image detector 30, and the subject table 15.
- the first grating is not limited to the absorption grating, but may be a phase grating.
- the multi-slit 35 (see FIG. 19) described above can be provided in the X-ray irradiation unit 11.
- FIG. 27 shows another modification of the X-ray imaging apparatus 301 of FIG.
- the imaging unit is the imaging unit 212 of the X-ray imaging apparatus 201 shown in FIG. 21, and is roughly configured by the first absorption grating 31 and the X-ray image detector 230.
- the arm member 361 is different from the X-ray imaging apparatus 301 shown in FIG. 25 in that the first absorption grating 31, the X-ray image detector 230, and the subject table 15 are supported.
- the first grating is not limited to the absorption grating, but may be a phase grating.
- the multi-slit 35 (see FIG. 19) described above can be provided in the X-ray irradiation unit 11.
- the first absorption grating 31 can be disposed between the X-ray irradiation unit 11 and the subject table 15.
- FIG. 28 shows the configuration of another example of a radiation imaging apparatus for explaining an embodiment of the present invention. Note that elements common to the above-described X-ray imaging apparatuses 1, 101, and 201 are denoted by common reference numerals, and description thereof is omitted or simplified.
- the arm member 61 supports the X-ray irradiation unit 11, the first and second absorption gratings 31 and 32, and the X-ray image detector 30. 1 differs from the X-ray imaging apparatus 1 shown in FIG. 1 in that it is supported by a support member (third support member) 461 different from the arm member 61. That is, in the X-ray imaging apparatus 401, the subject table 15 is separated from the X-ray imaging apparatus main body 2.
- the X-ray irradiating unit 11 is subject to shock caused when the subject H is placed on the subject table 15, vibration due to movement (body movement) of the subject H during or during imaging. And the transmission to the stand 13 that supports the imaging unit 12, and as described above, the displacement of the relative positions of the X-ray focal point 18 b and the first and second absorption gratings 31 and 32 is prevented or suppressed.
- the detection accuracy of the phase information of the subject H can be improved.
- the first grating is not limited to the absorption grating but may be a phase grating.
- the X-ray irradiation unit 11 can be provided with the multi slit 35 (see FIG. 19) described above.
- FIG. 29 shows a modification of the X-ray imaging apparatus 401 of FIG.
- the X-ray imaging apparatus shown in FIG. 29 is similar to the X-ray imaging apparatus 101 shown in FIG. 20 in that the first absorption grating 31 is disposed between the X-ray irradiation unit 11 and the subject table 15. Different from the X-ray imaging apparatus 401 shown in FIG. The subject table 15 is supported by a support member 461 different from the arm member 61 that supports the X-ray irradiation unit 11, the first and second absorption gratings 31 and 32, and the X-ray image detector 30. .
- the first grating is not limited to the absorption type grating but may be a phase type grating.
- the multi-slit 35 (see FIG. 19) described above can be provided in the X-ray irradiation unit 11.
- FIG. 30 shows another modification of the X-ray imaging apparatus 401 of FIG.
- the imaging unit is the imaging unit 212 of the X-ray imaging apparatus 201 shown in FIG. 21, and is roughly configured by the first absorption grating 31 and the X-ray image detector 230. It differs from the X-ray imaging apparatus 401 shown in FIG.
- the subject table 15 is supported by a support member 461 different from the arm member 61 that supports the X-ray irradiation unit 11, the first absorption type grating 31, and the X-ray image detector 230.
- the first grating is not limited to the absorption type grating but may be a phase type grating.
- the multi-slit 35 (see FIG. 19) described above can be provided in the X-ray irradiation unit 11.
- the first absorption grating 31 can be disposed between the X-ray irradiation unit 11 and the subject table 15.
- FIG. 31 shows the configuration of another example of the radiation imaging apparatus for explaining the embodiment of the present invention. Note that elements common to the above-described X-ray imaging apparatuses 1 and 201 are denoted by common reference numerals, and description thereof is omitted or simplified.
- the X-ray imaging apparatus 501 shown in FIG. 31 the X-ray irradiation unit 11 is supported by an arm member 61, and the imaging unit 12 and the subject table 15 are provided on a base (first stage) provided separately from the arm member 61. 2), the X-ray imaging apparatus 1 shown in FIG.
- the pedestal 561 for supporting the imaging unit 12 located on the subject table 15 and the lower side in the vertical direction (downstream of the subject table 15 in the X-ray traveling direction along the optical axis C) is a first absorption type.
- the structure is not affected when the subject H is arranged on the placement surface of the subject table 15 along the lattice pitch direction (x direction) of the lattice 31, and is thus configured as a structure having higher rigidity than the arm member 61. Can do.
- the base 561 is configured by a plurality of leg members connected to each other.
- the subject table 15 is installed on a base 561 via a buffer member 15c.
- the relative position shift of 32 can be prevented or suppressed by the rigid structure, and the detection accuracy of the phase information of the subject H can be improved.
- the first grating is not limited to the absorption grating but may be a phase grating.
- the multi-slit 35 (see FIG. 19) described above can be provided in the X-ray irradiation unit 11.
- FIG. 32 shows a modification of the X-ray imaging apparatus 501 of FIG.
- the X-ray imaging apparatus shown in FIG. 32 has an imaging unit that is an imaging unit 212 of the X-ray imaging apparatus 201 shown in FIG. 21, and is roughly configured by the first absorption grating 31 and the X-ray image detector 230. It differs from the X-ray imaging apparatus 501 shown in FIG.
- the X-ray irradiation unit 11 is supported by the arm member 61, and the imaging unit 212 and the subject table 15 are supported by a base 561 provided on the base 60 separately from the arm member 61.
- the first grating is not limited to the absorption type grating but may be a phase type grating.
- the multi-slit 35 (see FIG. 19) described above can be provided in the X-ray irradiation unit 11.
- FIG. 33 shows a configuration of another example of the radiation imaging apparatus for explaining the embodiment of the present invention.
- description is abbreviate
- the above-described X-ray imaging apparatus 1 irradiates X-rays substantially vertically downward, and basically performs imaging of the subject H in the supine position or the sitting position.
- the apparatus 601 performs imaging of the subject H in a standing position, and differs from the X-ray imaging apparatus 1 described above in that X-rays are irradiated in a substantially horizontal direction.
- the X-ray irradiation unit 11, the first absorption type grating 31, the second absorption type grating 32, and the X-ray image detector 30 are arranged in this order in a substantially horizontal direction, and an arm member 61 is supported.
- the arm member 61 deviates from a region where the first absorption type grating 31 is extended in the grating pitch direction (z direction), and the first absorption type grating 31 extends in the extending direction of the X-ray shielding part 31b (y direction). It extends in a substantially horizontal direction through a region extending in the horizontal direction.
- the subject table 15 is provided so that a subject H (for example, a knee joint) placed thereon is disposed between the X-ray irradiation unit 11 and the first absorption type grating 31, and the arm member 61. It is supported by another support member.
- a subject H for example, a knee joint
- the arm member 61 is configured to be pivotable about the pivot axis 62, and the subject H can be photographed from various directions by pivoting the arm member 61.
- the above-described multi slit 35 (see FIG. 19) can be provided in the X-ray irradiation unit 11.
- the first absorption type grating 31 is placed between the X-ray irradiation unit 11 and the subject H placed on the subject table 15. Can be arranged.
- the second absorption grating 32 can be omitted as in the X-ray imaging apparatuses 201 and 201A described above.
- an arm member (supporting the X-ray source 11, the first absorption grating 31, the second absorption grating 32, and the X-ray image detector 30).
- a second support member 661 may be provided.
- the present invention is not limited to X-rays, and radiation other than X-rays such as ⁇ -rays and ⁇ -rays can also be used. It is.
- the X-ray imaging apparatus other than the X-ray imaging apparatus 1 described above as in the X-ray imaging apparatus 1, the first grating is not limited to the absorption type grating but may be a phase type grating.
- a first radiation image including a radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and including a periodic intensity distribution through the radiation emitted from the radiation irradiation unit.
- a second grating that forms a second radiation image including a periodic intensity distribution by partially shielding the first radiation image, and the second radiation image.
- a radiation image detector for detecting and acquiring image data; and the radiation irradiating unit, the first grating, the second grating, and the radiation image detector extending in an arrangement direction of the radiation irradiating unit, And a first support member that supports the first grating, the second grating, and the radiation image detector, wherein the first support member places the first grating in the arrangement direction of the linear bodies.
- the radiographic apparatus according to the above (3) or (4) comprising a subject table disposed between the radiation irradiating unit and the first grating and on which a subject is placed.
- the radiographic apparatus according to (5) wherein the subject table is supported by the first support member, or the first support member and the second support member.
- the subject table is supported by a support member that supports the subject table via a buffer member that buffers force and vibration acting on the subject table. Radiography equipment.
- the radiation imaging apparatus according to any one of (2) to (4), wherein the subject table is disposed between the radiation irradiating unit and the first lattice and on which a subject is placed;
- a radiation imaging apparatus comprising: a third support member that supports the subject table.
- the subject table is supported by a support member that supports the subject table via a buffer member that buffers force and vibration acting on the subject table.
- Radiography equipment (15) The radiographic apparatus according to any one of (9) to (11), wherein the object table is disposed between the first grating and the second grating, and the object is placed thereon.
- a radiation imaging apparatus comprising: a third support member that supports the subject table.
- a phase contrast image is generated using at least one image data acquired by the radiographic image detector by imaging a subject.
- a radiation imaging apparatus including an arithmetic processing unit.
- a scanning mechanism for arranging the first grating and the second grating, and the arithmetic processing unit shoots a subject under the relative positional relationship between the first grating and the second grating.
- a radiation imaging apparatus that generates a phase contrast image using a plurality of image data acquired by the radiation image detector.
- the scanning mechanism may include either one of the first grating and the second grating within a plane on which the grating is arranged.
- the periodic intensity distribution of the second radiation image includes a periodic intensity distribution of the first radiation image and a periodic structure of the second grating.
- the arithmetic processing unit uses one image data obtained by photographing the subject and acquired by the radiation image detector, and a periodic pattern corresponding to the moire fringes in the image data. Radiation imaging apparatus for generating a phase contrast image based on the above.
- the arithmetic processing unit includes the plurality of pixels that constitute one unit, with three or more pixels arranged in a direction intersecting the moire fringe as one unit.
- a radiation imaging apparatus that calculates a signal obtained by interpolating pixel signal values and generates a phase contrast image based on a phase shift amount of the signal when there is a subject and when there is no subject.
- the arithmetic processing unit obtains a spatial frequency spectrum of the image data using Fourier transform, and extracts a fundamental frequency component of the periodic pattern from the spatial frequency spectrum.
- a radiation imaging apparatus that separates a frequency region that includes the same, and performs an inverse Fourier transform on the separated frequency region to generate a phase contrast image.
- a radiography apparatus arranged out of the extension area.
- the first support member and the second support member are arranged in a direction in which a linear body extends in the first lattice, A radiation imaging apparatus supporting the first grating and the radiation image detector with the radiation image detector interposed therebetween.
- the radiation imaging apparatus includes a subject table that is disposed between the radiation irradiation unit and the first lattice and on which a subject is placed.
- the subject table is supported by the first support member, or the first support member and the second support member.
- the subject table is supported by a support member that supports the subject table via a buffer member that buffers force and vibration acting on the subject table.
- Radiography equipment The radiation imaging apparatus according to any one of (23) to (25), wherein the object table is disposed between the radiation irradiating unit and the first grating and on which an object is placed;
- a radiation imaging apparatus comprising: a third support member that supports the subject table.
- a radiation imaging apparatus including an arithmetic processing unit that generates a phase contrast image.
- the radiation imaging apparatus wherein the radiation image detector has a resolution capable of resolving a periodic intensity distribution of the radiation image, and the periodic pattern is the radiation image.
- the radiographic apparatus corresponding to a periodic intensity distribution of (32)
- a first radiation image that includes a radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and that includes a periodic intensity distribution through the radiation emitted from the radiation irradiation unit.
- a second grating forming a second radiation image including a periodic intensity distribution generated by partially shielding the first radiation image, and the second radiation image.
- a radiation image detector that detects image data and acquires image data; and the radiation irradiator that extends in an arrangement direction of the radiation irradiator, the first grating, the second grating, and the radiation image detector.
- a first support member that supports the first grating, the second grating, and a second support member that supports the radiation image detector, wherein the first support member includes An extension of the first lattice extending in the direction of arrangement of the linear bodies
- a radiation imaging apparatus arranged away from a long region or an extended region obtained by extending the second lattice in the arrangement direction of the linear bodies.
- a radiation image detector that detects the radiation image to acquire image data, the radiation irradiating unit, the first grating, and the radiation image detector extending in an arrangement direction of the radiation
- a first support member that supports the irradiation unit; and a second support member that supports the first grating and the radiation image detector.
- the first support member includes the first grating.
- a radiation imaging apparatus arranged out of an extended region extending in the arrangement direction of the linear bodies.
- the first support member when the subject is arranged along the arrangement direction of the linear body group of the first lattice, the first support member does not become an obstacle, and the subject is appropriately arranged to be clear. A phase contrast image can be obtained.
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Abstract
A radiation imaging device (1) is provided with a first support member (61) that supports the following: a first grid (31) that allows the passage of radiation from a radiation emission unit (11) and forms a first radiation image that includes a periodic intensity distribution; a second grid (32) that forms a second radiation image that includes a periodic intensity distribution generated by partially obscuring the first radiation image; and a radiation image detector (30) that detects the second radiation image and acquires image data. The first support member is disposed offset from a first extended region that extends in the array direction of a linear body (31b) of the first grid.
Description
本発明は、放射線撮影装置に関する。
The present invention relates to a radiation imaging apparatus.
X線は、物質を構成する元素の原子番号と、物質の密度及び厚さとに依存して減衰するといった特性を有することから、被写体の内部を透視するためのプローブとして用いられている。X線を用いた撮影は、医療診断や非破壊検査等の分野において広く普及している。
X-rays are used as a probe for seeing through the inside of a subject because they have characteristics such as attenuation depending on the atomic numbers of elements constituting the substance and the density and thickness of the substance. X-ray imaging is widely used in fields such as medical diagnosis and non-destructive inspection.
一般的なX線撮影では、X線を放射するX線源とX線画像を検出するX線画像検出器との間に被写体を配置して、被写体の透過像を撮影する。この場合、X線源からX線画像検出器に向けて放射された各X線は、X線画像検出器までの経路上に存在する被写体を構成する物質の特性(原子番号、密度、厚さ)の差異に応じた量の減衰(吸収)を受けた後、X線画像検出器に入射する。この結果、被写体のX線透過像がX線画像検出器により検出され画像化される。X線画像検出器としては、X線増感紙とフイルムとの組み合わせや輝尽性蛍光体(蓄積性蛍光体)のほか、半導体回路を用いたフラットパネル検出器(FPD:Flat Panel Detector)が広く用いられている。
In general X-ray imaging, a subject is placed between an X-ray source that emits X-rays and an X-ray image detector that detects an X-ray image, and a transmission image of the subject is captured. In this case, each X-ray radiated from the X-ray source toward the X-ray image detector has characteristics (atomic number, density, thickness) of the substance constituting the subject existing on the path to the X-ray image detector. ), The light is incident on the X-ray image detector. As a result, an X-ray transmission image of the subject is detected and imaged by the X-ray image detector. X-ray image detectors include a combination of an X-ray intensifying screen and film, a stimulable phosphor (accumulating phosphor), and a flat panel detector (FPD: Flat Panel Detector) using a semiconductor circuit. Widely used.
しかし、X線吸収能は、原子番号が小さい元素からなる物質ほど低くなり、生体軟部組織やソフトマテリアルなどでは、X線吸収能の差が小さく、従ってX線透過像としての十分な画像の濃淡(コントラスト)が得られないといった問題がある。例えば、人体の関節を構成する軟骨部とその周辺の関節液は、いずれも殆どの成分が水であり、両者のX線の吸収量の差が小さいため、画像のコントラストが得られにくい。
However, the X-ray absorptivity becomes lower as a substance composed of an element having a smaller atomic number, and the difference in the X-ray absorptivity is small in a soft tissue or soft material of a living body. There is a problem that (contrast) cannot be obtained. For example, most of the components of the cartilage part constituting the joint of the human body and the joint fluid in the vicinity thereof are water, and the difference in the amount of X-ray absorption between the two is small, so that it is difficult to obtain image contrast.
このような問題を背景に、近年、被写体によるX線の強度変化に代えて、被写体によるX線の位相変化(角度変化)に基づいた画像(以下、位相コントラスト画像と称する)を得るX線位相イメージングの研究が盛んに行われている。一般に、X線が物体に入射したとき、X線の強度よりも位相のほうが高い相互作用を示すことが知られている。このため、位相差を利用したX線位相イメージングでは、X線吸収能が低い弱吸収物体であっても高コントラストの画像を得ることができ、例えば手や足の指節間関節、肘関節、膝関節といった関節の軟骨部の可視化に有用である。
Against the background of such problems, in recent years, an X-ray phase for obtaining an image (hereinafter referred to as a phase contrast image) based on an X-ray phase change (angle change) by an object instead of an X-ray intensity change by an object. Imaging research is actively conducted. In general, it is known that when X-rays are incident on an object, the interaction is higher in phase than in X-ray intensity. For this reason, in X-ray phase imaging using a phase difference, it is possible to obtain a high-contrast image even for a weakly absorbing object having a low X-ray absorption ability, for example, an interphalangeal joint of a hand or a foot, an elbow joint, This is useful for visualizing the cartilage of joints such as knee joints.
このようなX線位相イメージングの一種として、近年、2枚の透過回折格子(位相型格子及び吸収型格子)とX線画像検出器とからなるX線タルボ干渉計を用いたX線撮影装置が考案されている(例えば、特許文献1、2参照)。
As a kind of such X-ray phase imaging, in recent years, an X-ray imaging apparatus using an X-ray Talbot interferometer comprising two transmission diffraction gratings (phase type grating and absorption type grating) and an X-ray image detector has been proposed. It has been devised (for example, see Patent Documents 1 and 2).
X線タルボ干渉計は、被写体の背後に第1の回折格子(位相型格子あるいは吸収型格子)を配置し、第1の回折格子の格子ピッチとX線波長で決まる特定距離(タルボ干渉距離)だけ下流に第2の回折格子(吸収型格子)を配置し、その背後にX線画像検出器を配置することにより構成される。上記タルボ干渉距離とは、第1の回折格子を通過したX線が、タルボ干渉効果によって、周期的強度分布を呈する自己像(以下、G1像という)を形成する距離であり、このG1像は、X線源と第1の回折格子との間に配置された被写体とX線との相互作用(位相変化)により変調を受ける。
In the X-ray Talbot interferometer, a first diffraction grating (phase type grating or absorption type grating) is arranged behind a subject, and a specific distance (Talbot interference distance) determined by the grating pitch of the first diffraction grating and the X-ray wavelength. The second diffraction grating (absorption type grating) is disposed only downstream, and the X-ray image detector is disposed behind the second diffraction grating. The Talbot interference distance is a distance at which X-rays that have passed through the first diffraction grating form a self-image (hereinafter referred to as a G1 image) that exhibits a periodic intensity distribution due to the Talbot interference effect. And modulated by the interaction (phase change) between the subject and the X-rays disposed between the X-ray source and the first diffraction grating.
X線タルボ干渉計では、G1像と第2の回折格子との重ね合わせにより生じるモアレ縞を検出し、モアレ縞に対応して画像に現れる周期パターンの被写体による変調を解析することによって被写体の位相情報を取得する。画像に現れる周期パターンの解析方法としては、たとえば、縞走査法が知られている。この縞走査法によると、第1の回折格子に対して第2の回折格子を、第1の回折格子の面にほぼ平行で、かつ第1の回折格子の格子ピッチ方向にほぼ平行な方向に、第2の回折格子の格子ピッチを等分割した走査ピッチで並進移動させながら複数回の撮影を行い、得られる複数の画像データ間で対応する画素毎の信号値の変化から、被写体で屈折したX線の角度分布(位相シフトの微分像)を取得し、この角度分布に基づいて被写体の位相コントラスト画像を得ることができる。
In the X-ray Talbot interferometer, the moiré fringes generated by the superposition of the G1 image and the second diffraction grating are detected, and the phase of the subject is analyzed by analyzing the modulation of the periodic pattern appearing in the image corresponding to the moire fringes. Get information. For example, a fringe scanning method is known as a method for analyzing a periodic pattern appearing in an image. According to this fringe scanning method, the second diffraction grating is arranged with respect to the first diffraction grating in a direction substantially parallel to the plane of the first diffraction grating and substantially parallel to the grating pitch direction of the first diffraction grating. , Taking multiple shots while translating the grating pitch of the second diffraction grating at equal scan pitches, and refracting the subject from the change in the corresponding signal value for each pixel between the obtained multiple image data An X-ray angular distribution (phase shift differential image) is obtained, and a phase contrast image of the subject can be obtained based on the angular distribution.
縞走査法によって取得される位相シフトの微分は、第1の回折格子の格子ピッチ方向に関するものであり、この位相シフトの微分に基づいて得られる位相コントラスト画像には、格子ピッチ方向に交差する被写体の縁部が描出され、特に格子ピッチ方向に略直交する被写体の縁部が明瞭に描出される。即ち、被写体の配置は、第1の回折格子の格子ピッチ方向の制約を受けることとなる。例えば、指節間関節、肘関節、膝関節といった関節の位相コントラスト画像において関節の軟骨部を明瞭に描出するには、指や腕や脚を格子ピッチ方向に略沿って配置する必要がある。
The phase shift derivative obtained by the fringe scanning method is related to the grating pitch direction of the first diffraction grating, and the phase contrast image obtained based on this phase shift derivative includes an object that intersects the grating pitch direction. In particular, the edge of the subject substantially perpendicular to the lattice pitch direction is clearly depicted. That is, the arrangement of the subject is restricted by the grating pitch direction of the first diffraction grating. For example, in order to clearly depict a cartilage portion of a joint in phase contrast images of joints such as interphalangeal joints, elbow joints, and knee joints, it is necessary to arrange fingers, arms, and legs substantially along the lattice pitch direction.
ここで、特許文献1、2に記載されたX線撮影装置は、鉛直方向に並べられたX線源、第1の回折格子、第2の回折格子、検出器、及び被写体台をアーム部材によって支持してなる、いわゆる縦型のX線撮影装置であり、被写体台は、X線源と第1の回折格子との間、あるいは第1の回折格子と第2の回折格子との間に配置される。アーム部材は、被写体台に対して第1の回折格子の格子ピッチ方向に隣設されており、かかる構成によると、腕や脚などの比較的長尺な被写体を第1の回折格子の格子ピッチ方向に沿って配置する際に、アーム部材が障害となり得る。
Here, in the X-ray imaging apparatuses described in Patent Documents 1 and 2, an X-ray source, a first diffraction grating, a second diffraction grating, a detector, and a subject table arranged in a vertical direction are provided by an arm member. It is a so-called vertical X-ray imaging apparatus that is supported, and the object table is disposed between the X-ray source and the first diffraction grating, or between the first diffraction grating and the second diffraction grating. Is done. The arm member is provided adjacent to the subject table in the direction of the grating pitch of the first diffraction grating. According to this configuration, a relatively long subject such as an arm or a leg can be placed on the grating pitch of the first diffraction grating. The arm member can become an obstacle when it is arranged along the direction.
本発明は、上述した事情に鑑みなされたものであり、被写体を適切に配置することができ、明瞭な位相コントラスト画像を得ることのできる放射線撮影装置を提供することを目的とする。
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a radiation imaging apparatus capable of appropriately arranging a subject and obtaining a clear phase contrast image.
(1) 放射線照射部と、多数の線状体が配列されてなる周期的構造をそれぞれ有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む第1の放射線像を形成する第1の格子、及び前記第1の放射線像を部分的に遮蔽することによって周期的強度分布を含む第2の放射線像を形成する第2の格子と、前記第2の放射線像を検出して画像データを取得する放射線画像検出器と、前記放射線照射部、前記第1の格子、前記第2の格子、及び前記放射線画像検出器の並び方向に延在し、これら放射線照射部、第1の格子、第2の格子、及び放射線画像検出器を支持する第1の支持部材と、を備え、前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域、又は前記第2の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。
(2) 放射線照射部と、多数の線状体が配列されてなる周期的構造を有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む放射線像を形成する第1の格子と、前記放射線像を検出して画像データを取得する放射線画像検出器と、前記放射線照射部、前記第1の格子、及び前記放射線画像検出器の並び方向に延在し、これら放射線照射部、第1の格子、及び放射線画像検出器を支持する第1の支持部材と、を備え、前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。 (1) A first radiation image including a radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and including a periodic intensity distribution through the radiation emitted from the radiation irradiation unit. A second grating that forms a second radiation image including a periodic intensity distribution by partially shielding the first radiation image, and the second radiation image. A radiation image detector for detecting and acquiring image data; and the radiation irradiating unit, the first grating, the second grating, and the radiation image detector extending in an arrangement direction of the radiation irradiating unit, And a first support member that supports the first grating, the second grating, and the radiation image detector, wherein the first support member places the first grating in the arrangement direction of the linear bodies. An extended region, or an array of linear bodies of the second lattice Radiation imaging apparatus arranged out of the extended area extending in the direction.
(2) A radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and a radiation image including a periodic intensity distribution is formed by passing the radiation emitted from the radiation irradiation unit. 1 and a radiation image detector that detects the radiation image to acquire image data, the radiation irradiating unit, the first grating, and the radiation image detector extend in the arrangement direction of the radiation. An irradiation unit, a first grating, and a first support member that supports the radiation image detector, wherein the first support member extends the first grating in the arrangement direction of the linear bodies. A radiography apparatus arranged out of the extension area.
(2) 放射線照射部と、多数の線状体が配列されてなる周期的構造を有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む放射線像を形成する第1の格子と、前記放射線像を検出して画像データを取得する放射線画像検出器と、前記放射線照射部、前記第1の格子、及び前記放射線画像検出器の並び方向に延在し、これら放射線照射部、第1の格子、及び放射線画像検出器を支持する第1の支持部材と、を備え、前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。 (1) A first radiation image including a radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and including a periodic intensity distribution through the radiation emitted from the radiation irradiation unit. A second grating that forms a second radiation image including a periodic intensity distribution by partially shielding the first radiation image, and the second radiation image. A radiation image detector for detecting and acquiring image data; and the radiation irradiating unit, the first grating, the second grating, and the radiation image detector extending in an arrangement direction of the radiation irradiating unit, And a first support member that supports the first grating, the second grating, and the radiation image detector, wherein the first support member places the first grating in the arrangement direction of the linear bodies. An extended region, or an array of linear bodies of the second lattice Radiation imaging apparatus arranged out of the extended area extending in the direction.
(2) A radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and a radiation image including a periodic intensity distribution is formed by passing the radiation emitted from the radiation irradiation unit. 1 and a radiation image detector that detects the radiation image to acquire image data, the radiation irradiating unit, the first grating, and the radiation image detector extend in the arrangement direction of the radiation. An irradiation unit, a first grating, and a first support member that supports the radiation image detector, wherein the first support member extends the first grating in the arrangement direction of the linear bodies. A radiography apparatus arranged out of the extension area.
本発明によれば、第1の格子の線状体群の配列方向に沿って被写体を配置する際に、第1の支持部材が障害となることがなく、被写体を適切に配置して明瞭な位相コントラスト画像を得ることができる。
According to the present invention, when the subject is arranged along the arrangement direction of the linear body group of the first lattice, the first support member does not become an obstacle, and the subject is appropriately arranged to be clear. A phase contrast image can be obtained.
図1は、本発明の実施形態を説明するための放射線撮影装置の一例の構成を示し、図2は、図1の放射線撮影装置の制御ブロックを示す。
FIG. 1 shows a configuration of an example of a radiographic apparatus for explaining an embodiment of the present invention, and FIG. 2 shows a control block of the radiographic apparatus of FIG.
X線撮影装置1は、X線撮影装置本体2と、コンソール3とに大別される。X線撮影装置本体2は、被写体HにX線を照射するX線照射部11と、X線照射部11から放射されて被写体Hを透過したX線を検出し、画像データを生成する撮影部12とを備えている。コンソール3は、操作者の操作に基づいてX線撮影装置本体2のX線照射部11の曝射動作や撮影部12の撮影動作を制御するとともに、撮影部12により取得された画像データを演算処理して位相コントラスト画像を生成する。
The X-ray imaging apparatus 1 is roughly divided into an X-ray imaging apparatus main body 2 and a console 3. The X-ray imaging apparatus body 2 includes an X-ray irradiation unit 11 that irradiates the subject H with X-rays, and an imaging unit that detects X-rays emitted from the X-ray irradiation unit 11 and transmitted through the subject H, and generates image data. 12. The console 3 controls the exposure operation of the X-ray irradiation unit 11 and the imaging operation of the imaging unit 12 of the X-ray imaging apparatus body 2 based on the operation of the operator, and calculates image data acquired by the imaging unit 12 Process to generate a phase contrast image.
X線照射部11及び撮影部12は、床上に設置されたスタンド13により支持されている。スタンド13は、床に固定されるベース60と、ベース60から鉛直方向(図示の例では、z方向)に延びるアーム部材61とで構成されている。X線照射部11は、アーム部材61の先端部に取り付けられている。撮影部12は、X線照射部11に対向して配置され、アーム部材61の略中央部に取り付けられている。
The X-ray irradiation unit 11 and the imaging unit 12 are supported by a stand 13 installed on the floor. The stand 13 includes a base 60 fixed to the floor and an arm member 61 extending from the base 60 in the vertical direction (z direction in the illustrated example). The X-ray irradiation unit 11 is attached to the distal end portion of the arm member 61. The imaging unit 12 is disposed to face the X-ray irradiation unit 11 and is attached to a substantially central portion of the arm member 61.
X線照射部11は、X線源としてのX線管18と、コリメータユニット19とを備えている。X線管18は、陽極回転型であり、X線源制御部17の制御に基づいて高電圧発生器16から印加される高電圧に応じて、電子放出源(陰極)としてのフィラメント(図示せず)から電子線を放出し、所定の速度で回転する回転陽極18aに衝突させることによりX線を発生する。この回転陽極18aの電子線の衝突部分がX線焦点18bとなる。コリメータユニット19は、X線管18から発せられたX線のうち、被写体Hの検査領域に寄与しない部分を遮蔽するように照射野を制限する可動式のコリメータ19aを有している。
The X-ray irradiation unit 11 includes an X-ray tube 18 as an X-ray source and a collimator unit 19. The X-ray tube 18 is of an anode rotating type, and is a filament (not shown) as an electron emission source (cathode) according to a high voltage applied from the high voltage generator 16 based on the control of the X-ray source control unit 17. X-rays are generated by emitting an electron beam from the motor and causing it to collide with the rotating anode 18a rotating at a predetermined speed. The colliding portion of the rotating anode 18a with the electron beam becomes the X-ray focal point 18b. The collimator unit 19 has a movable collimator 19 a that limits the irradiation field so as to shield a portion of the X-rays emitted from the X-ray tube 18 that does not contribute to the inspection area of the subject H.
撮影部12は、被写体HによるX線の位相変化(角度変化)を検出するための第1の吸収型格子31と、第1の吸収型格子31を通過したX線によって形成されるX線像(以下、このX線像をG1像と称する)を検出する検出部14とを備えている。本X線撮影装置1は、詳細は後述するが、縞走査法を用いて位相コントラスト画像を生成するものであり、検出部14には、G1像に重ね合わされる第2の吸収型格子32と、第2の吸収型格子32が重ね合わされたG1像を検出するX線画像検出器30と、第2の吸収型格子32を所定のピッチで並進移動させる走査機構33とが設けられている。この走査機構33は、例えば、圧電素子等のアクチュエータにより構成される。
The imaging unit 12 includes an X-ray image formed by a first absorption type grating 31 for detecting an X-ray phase change (angle change) caused by the subject H and an X-ray that has passed through the first absorption type grating 31. And a detection unit 14 that detects (hereinafter, this X-ray image is referred to as a G1 image). Although the details will be described later, the X-ray imaging apparatus 1 generates a phase contrast image using a fringe scanning method. The detection unit 14 includes a second absorption grating 32 superimposed on the G1 image, An X-ray image detector 30 that detects the G1 image on which the second absorption type grating 32 is superimposed, and a scanning mechanism 33 that translates the second absorption type grating 32 at a predetermined pitch are provided. The scanning mechanism 33 is configured by an actuator such as a piezoelectric element, for example.
図示の例において、撮影部12は、第1の吸収型格子31及び検出部14(第2の吸収型格子32及びX線画像検出器30)を1つの筐体に収納してユニットとして構成され、アーム部材61に取り付けられているが、第1の吸収型格子31及び第2の吸収型格子32並びにX線画像検出器30を、それぞれ単独で適宜な筐体に収納したうえで、個別にアーム部材61に取り付けるようにしてもよい。また、第1の吸収型格子31及び第2の吸収型格子32並びにX線画像検出器30を適宜組み合わせてユニット化したうえでアーム部材61に取り付けるようにしてもよく、例えば、第1の吸収型格子31及び第2の吸収型格子32をユニット化してアーム部材61に取り付け、X線画像検出器30のみ単独でアーム部材61に取り付けるようにしてもよいし、又は第2の吸収型格子32及びX線画像検出器30をユニット化してアーム部材61に取り付け、第1の吸収型格子31のみ単独でアーム部材61に取り付けるようにしてもよい。
In the illustrated example, the imaging unit 12 is configured as a unit in which the first absorption type grating 31 and the detection unit 14 (the second absorption type grating 32 and the X-ray image detector 30) are housed in one housing. Although attached to the arm member 61, the first absorption type grating 31, the second absorption type grating 32, and the X-ray image detector 30 are individually housed in appropriate housings, and individually. You may make it attach to the arm member 61. FIG. Further, the first absorption type grating 31, the second absorption type grating 32, and the X-ray image detector 30 may be appropriately combined to be unitized and attached to the arm member 61, for example, the first absorption type The mold grating 31 and the second absorption grating 32 may be unitized and attached to the arm member 61, and only the X-ray image detector 30 may be attached alone to the arm member 61, or the second absorption grating 32 may be attached. Alternatively, the X-ray image detector 30 may be unitized and attached to the arm member 61, and only the first absorption type grating 31 may be attached to the arm member 61 alone.
また、X線照射部11及び撮影部12を支持するアーム部材61には、被写体Hが載置される被写体台15が取り付けられている。被写体台15は、X線照射部11と撮影部12との間、より詳細には、X線照射部11と第1の吸収型格子31との間に配置されている。
Further, the subject table 15 on which the subject H is placed is attached to the arm member 61 that supports the X-ray irradiation unit 11 and the imaging unit 12. The subject table 15 is disposed between the X-ray irradiation unit 11 and the imaging unit 12, more specifically, between the X-ray irradiation unit 11 and the first absorption grating 31.
コンソール3には、CPU、ROM、RAM等からなる制御装置20が設けられている。制御装置20には、操作者が撮影指示やその指示内容を入力する入力装置21と、撮影部12により取得された画像データを演算処理してX線画像を生成する演算処理部22と、X線画像を記憶する記憶部23と、X線画像等を表示するモニタ24と、X線撮影装置1の各部と接続されるインターフェース(I/F)25とがバス26を介して接続されている。
The console 3 is provided with a control device 20 comprising a CPU, ROM, RAM and the like. The control device 20 includes an input device 21 through which an operator inputs an imaging instruction and the content of the instruction, an arithmetic processing unit 22 that performs arithmetic processing on the image data acquired by the imaging unit 12 and generates an X-ray image, and X A storage unit 23 for storing line images, a monitor 24 for displaying X-ray images and the like, and an interface (I / F) 25 connected to each unit of the X-ray imaging apparatus 1 are connected via a bus 26. .
入力装置21としては、例えば、スイッチ、タッチパネル、マウス、キーボード等を用いることが可能であり、入力装置21の操作により、X線管電圧やX線照射時間等のX線撮影条件、撮影タイミング等が入力される。モニタ24は、液晶ディスプレイ等からなり、制御装置20の制御により、X線撮影条件等の文字やX線画像を表示する。
As the input device 21, for example, a switch, a touch panel, a mouse, a keyboard, or the like can be used. By operating the input device 21, X-ray imaging conditions such as X-ray tube voltage and X-ray irradiation time, imaging timing, and the like. Is entered. The monitor 24 includes a liquid crystal display or the like, and displays characters such as X-ray imaging conditions and X-ray images under the control of the control device 20.
図3及び図4は、撮影部12の構成を模式的に示す。
3 and 4 schematically show the configuration of the photographing unit 12.
第1の吸収型格子31は、基板31aと、この基板31aに配置された複数のX線遮蔽部31b(高放射線吸収部)とから構成されている。同様に、第2の吸収型格子32は、基板32aと、この基板32aに配置された複数のX線遮蔽部32b(高放射線吸収部)とから構成されている。基板31a,32aは、いずれもX線を透過させるシリコン、ガラス、樹脂、等のX線透過性部材により形成されている。
The first absorption type grating 31 includes a substrate 31a and a plurality of X-ray shielding portions 31b (high radiation absorption portions) disposed on the substrate 31a. Similarly, the second absorption grating 32 includes a substrate 32a and a plurality of X-ray shielding portions 32b (high radiation absorption portions) arranged on the substrate 32a. The substrates 31a and 32a are each formed of an X-ray transmissive member such as silicon, glass, resin, or the like that transmits X-rays.
X線遮蔽部31bは、X線照射部11から放射されるX線の光軸Cに直交する面内の一方向に延伸した線状の部材で構成される。各X線遮蔽部31bの材料としては、X線吸収性に優れるものが好ましく、例えば、金、白金等の重金属であることが好ましい。これらのX線遮蔽部31bは、金属メッキ法や蒸着法によって形成することが可能である。そして、X線遮蔽部31bは、X線の光軸Cに直交する面内において、上記一方向と直交する方向(以後、x方向とする)に一定の格子ピッチp1で、互いに所定の間隔d1を空けて配列されている。
The X-ray shielding part 31 b is configured by a linear member extending in one direction in a plane orthogonal to the optical axis C of the X-rays emitted from the X-ray irradiation part 11. As a material of each X-ray shielding part 31b, a material excellent in X-ray absorption is preferable, and for example, a heavy metal such as gold or platinum is preferable. These X-ray shielding portions 31b can be formed by a metal plating method or a vapor deposition method. Then, the X-ray shielding portion 31b is in a plane perpendicular to the optical axis C of the X-ray, the direction (hereinafter, x and direction) orthogonal to the one direction at a constant grating pitch p 1 to each other a predetermined distance d 1 is arranged with a gap.
X線遮蔽部32bもまた、X線照射部11から放射されるX線の光軸Cに直交する面内の一方向に延伸した線状の部材で構成される。各X線遮蔽部32bの材料としては、金、白金等の重金属といったX線吸収性に優れるものが好ましく、これらのX線遮蔽部32bは、金属メッキ法や蒸着法によって形成することが可能である。そして、X線遮蔽部32bは、X線の光軸Cに直交する面内において、上記一方向と直交する方向(x方向)に一定の格子ピッチp2で、互いに所定の間隔d2を空けて配列されている。
The X-ray shielding part 32b is also composed of a linear member extending in one direction in a plane perpendicular to the optical axis C of the X-rays emitted from the X-ray irradiation part 11. As a material of each X-ray shielding part 32b, a material having excellent X-ray absorption such as heavy metals such as gold and platinum is preferable, and these X-ray shielding parts 32b can be formed by a metal plating method or a vapor deposition method. is there. Then, X-ray shielding portion 32b, in the plane orthogonal to the optical axis C of the X-ray, at a constant grating pitch p 2 in the direction (x-direction) orthogonal to the one direction, at a predetermined interval d 2 from each other Are arranged.
以上のように構成される第1及び第2の吸収型格子31,32は、入射X線に位相差を与えるものでなく、強度差を与えるものであるため、振幅型格子とも称される。なお、上記間隔d1,d2の領域であるスリット部(低放射線吸収部)は空隙でなくてもよく、例えば、高分子や軽金属などのX線低吸収材で該空隙を充填してもよい。
Since the first and second absorption gratings 31 and 32 configured as described above do not give a phase difference to incident X-rays but give an intensity difference, they are also called amplitude gratings. The slit portions (low radiation absorbing portions) that are the regions of the distances d 1 and d 2 may not be voids. For example, the gaps may be filled with an X-ray low absorbing material such as a polymer or a light metal. Good.
第1及び第2の吸収型格子31,32は、タルボ干渉効果の有無に係らず、スリット部を通過したX線をほぼ幾何学的に投影するように構成されている。より詳細には、間隔d1,d2を、X線照射部11から放射されるX線の実効波長より十分大きな値とすることで、照射X線の大部分はスリット部での回折を受けずに、第1の吸収型格子31の後方に第1の吸収型格子31の自己像を形成するように構成することができる。例えば、放射線源のターゲットとしてタングステンを用い、管電圧を50kVとした場合には、X線の実効波長は、約0.4Åである。この場合には、間隔d1,d2を、1~10μm程度とすれば、スリット部を通過した放射線が形成する放射線像は回折の効果を無視できる程度になり、第1の吸収型格子31の後方に、第1の吸収型格子31の自己像がほぼ幾何学的に投影される。
The first and second absorption type gratings 31 and 32 are configured to project the X-rays that have passed through the slit portion almost geometrically regardless of the presence or absence of the Talbot interference effect. More specifically, by setting the distances d 1 and d 2 to a value sufficiently larger than the effective wavelength of X-rays emitted from the X-ray irradiation unit 11, most of the irradiation X-rays are diffracted by the slits. Instead, a self-image of the first absorption type grating 31 can be formed behind the first absorption type grating 31. For example, when tungsten is used as the target of the radiation source and the tube voltage is 50 kV, the effective wavelength of X-ray is about 0.4 mm. In this case, if the distances d 1 and d 2 are set to about 1 to 10 μm, the radiation image formed by the radiation that has passed through the slit portion becomes such that the effect of diffraction can be ignored, and the first absorption grating 31 can be ignored. The self-image of the first absorption-type grating 31 is projected almost geometrically.
X線照射部11から放射されるX線は、平行ビームではなく、X線焦点18bを発光点としたコーンビームであるため、G1像は、X線焦点18bからの距離に比例して拡大される。第2の吸収型格子32は、そのスリット部が、第2の吸収型格子32の位置におけるG1像の周期的強度分布のパターンとほぼ一致するように決定されている。すなわち、X線焦点18bから第1の吸収型格子31までの距離をL1、第1の吸収型格子31から第2の吸収型格子32までの距離をL2とした場合に、格子ピッチp2は、次式(1)の関係を満たすように決定される。
Since the X-ray radiated from the X-ray irradiation unit 11 is not a parallel beam but a cone beam with the X-ray focal point 18b as a light emitting point, the G1 image is enlarged in proportion to the distance from the X-ray focal point 18b. The The slits of the second absorption type grating 32 are determined so as to substantially match the pattern of the periodic intensity distribution of the G1 image at the position of the second absorption type grating 32. That is, when the distance from the X-ray focal point 18b to the first absorption grating 31 is L 1 and the distance from the first absorption grating 31 to the second absorption grating 32 is L 2 , the grating pitch p 2 is determined so as to satisfy the relationship of the following formula (1).
第1の吸収型格子31から第2の吸収型格子32までの距離L2は、タルボ干渉計では、第1の回折格子の格子ピッチとX線波長とで決まるタルボ干渉距離に制約されるが、本X線撮影装置1では、第1の吸収型格子31による入射X線の回折の影響が少ない構成であって、G1像が、第1の吸収型格子31の後方でほぼ相似的に得られるため、該距離L2を、タルボ干渉距離と無関係に設定することができる。
In the Talbot interferometer, the distance L 2 from the first absorption type grating 31 to the second absorption type grating 32 is limited to the Talbot interference distance determined by the grating pitch of the first diffraction grating and the X-ray wavelength. The X-ray imaging apparatus 1 has a configuration in which the influence of the incident X-ray diffraction by the first absorption type grating 31 is small, and the G1 image is obtained almost similarly behind the first absorption type grating 31. is therefore, the distance L 2, can be set independently of the Talbot distance.
撮影部12は、タルボ干渉計を構成するものではないが、第1の吸収型格子31でX線を回折すると仮定した場合のタルボ干渉距離Zは、第1の吸収型格子31の格子ピッチp1、第2の吸収型格子32の格子ピッチp2、X線波長(実効波長)λ、及び正の整数mを用いて、次式(2)で表される。
Although the imaging unit 12 does not constitute a Talbot interferometer, the Talbot interference distance Z when it is assumed that X-rays are diffracted by the first absorption type grating 31 is the grating pitch p of the first absorption type grating 31. 1 , using the grating pitch p 2 of the second absorption grating 32, the X-ray wavelength (effective wavelength) λ, and a positive integer m, the following expression (2).
式(2)は、X線照射部11から放射されるX線がコーンビームである場合のタルボ干渉距離を表す式であり、「Timm Weitkamp, et al., Proc. of SPIE, Vol. 6318, 2006年 63180S-1項」により知られている。
Expression (2) is an expression representing the Talbot interference distance when the X-ray emitted from the X-ray irradiation unit 11 is a cone beam, “Timm 、 Weitkamp, et al., Proc. Of SPIE, Vol. 6318, It is known from “2006 63180S-1”.
本X線撮影装置1では、距離L2を、m=1の場合の最小のタルボ干渉距離Zより短い値に設定することで、撮影部12の薄型化を図っている。すなわち、距離L2は、次式(3)を満たす範囲の値に設定される。
In the present X-ray imaging apparatus 1, the imaging unit 12 is thinned by setting the distance L 2 to a value shorter than the minimum Talbot interference distance Z when m = 1. That is, the distance L 2 is set to a value in the range satisfying the following equation (3).
なお、X線照射部11から放射されるX線が実質的に平行ビームとみなせる場合のタルボ干渉距離Zは次式(4)となり、距離L2を、次式(5)を満たす範囲の値に設定する。
Incidentally, Talbot distance Z by the following equation (4) and in the case of X-rays emitted from the X-ray irradiation unit 11 can be regarded as substantially parallel beams, a distance L 2, the value of the range that satisfies the following equation (5) Set to.
ただし、距離L2は、必ずしも式(3)ないし式(5)を満たす必要はなく、例えば撮影部12の薄型化の要請がない場合などには、式(3)ないし式(5)から外れる範囲の値も採り得る。
However, the distance L 2 does not necessarily satisfy the expressions (3) to (5), and deviates from the expressions (3) to (5), for example, when there is no request for thinning of the photographing unit 12. Range values can also be taken.
図5は、X線画像検出器30の構成を模式的に示す。
FIG. 5 schematically shows the configuration of the X-ray image detector 30.
X線画像検出器30は、薄膜トランジスタ(TFT:Thin Film Transistor)パネルをベースとした平面型検出器(FPD:Flat Panel Detector)が用いられ、X線を電荷に変換して蓄積する複数の画素40がTFTアクティブマトリクス基板上に2次元配列されてなる受像部41と、受像部41からの電荷の読み出しタイミングを制御する走査回路42と、各画素40に蓄積された電荷を読み出し、電荷を画像データに変換して記憶する読み出し回路43と、画像データをコンソール3のI/F25を介して演算処理部22に送信するデータ送信回路44とから構成されている。なお、走査回路42と各画素40とは、行毎に走査線45によって接続されており、読み出し回路43と各画素40とは、列毎に信号線46によって接続されている。
The X-ray image detector 30 uses a flat panel detector (FPD: Flat Panel Detector) based on a thin film transistor (TFT: Thin Film Transistor) panel, and converts a plurality of pixels 40 by converting X-rays into electric charges. Are two-dimensionally arranged on the TFT active matrix substrate, a scanning circuit 42 for controlling the charge readout timing from the image receiver 41, the charges accumulated in each pixel 40 are read out, and the charges are converted into image data. And a data transmission circuit 44 that transmits the image data to the arithmetic processing unit 22 via the I / F 25 of the console 3. The scanning circuit 42 and each pixel 40 are connected by a scanning line 45 for each row, and the readout circuit 43 and each pixel 40 are connected by a signal line 46 for each column.
各画素40は、アモルファスセレン等の変換層(図示せず)でX線を電荷に直接変換し、変換された電荷を下部の電極に接続されたキャパシタ(図示せず)に蓄積する直接変換型のX線検出素子として構成することができる。各画素40には、TFTスイッチ(図示せず)が接続され、TFTスイッチのゲート電極が走査線45、ソース電極がキャパシタ、ドレイン電極が信号線46に接続される。TFTスイッチが走査回路42からの駆動パルスによってON状態になると、キャパシタに蓄積された電荷が信号線46に読み出される。
Each pixel 40 is a direct conversion type in which X-rays are directly converted into electric charges by a conversion layer (not shown) such as amorphous selenium and the converted electric charges are stored in a capacitor (not shown) connected to the lower electrode. The X-ray detection element can be configured. A TFT switch (not shown) is connected to each pixel 40, and the gate electrode of the TFT switch is connected to the scanning line 45, the source electrode is connected to the capacitor, and the drain electrode is connected to the signal line 46. When the TFT switch is turned on by the drive pulse from the scanning circuit 42, the charge accumulated in the capacitor is read out to the signal line 46.
なお、各画素40は、X線を可視光に変換するシンチレータを併用し、シンチレータにて変換された可視光を電荷に変換して蓄積する間接変換型のX線検出素子として構成することも可能である。シンチレータを形成する蛍光体としては、例えばテルビウム賦活酸化ガドリニウム(Gd2O2S:Tb)やタリウム賦活ヨウ化セシウム(CsI:Tl)などが用いられる。また、X線画像検出器としては、TFTパネルをベースとしたFPDに限られず、CCDセンサやCMOSセンサ等の固体撮像素子をベースとした各種のX線画像検出器を用いることも可能である。
Each pixel 40 can also be configured as an indirect conversion type X-ray detection element that uses a scintillator that converts X-rays into visible light, and converts visible light converted by the scintillator into electric charge and accumulates it. It is. Examples of the phosphor forming the scintillator include terbium activated gadolinium oxide (Gd 2 O 2 S: Tb) and thallium activated cesium iodide (CsI: Tl). The X-ray image detector is not limited to an FPD based on a TFT panel, and various X-ray image detectors based on a solid-state imaging device such as a CCD sensor or a CMOS sensor can also be used.
読み出し回路43は、積分アンプ回路、A/D変換器、補正回路、及び画像メモリにより構成されている。積分アンプ回路は、各画素40から信号線46を介して出力された電荷を積分して電圧信号(画像信号)に変換して、A/D変換器に入力する。A/D変換器は、入力された画像信号をデジタルの画像データに変換して補正回路に入力する。補正回路は、画像データに対して、オフセット補正、ゲイン補正、及びリニアリティ補正を行い、補正後の画像データを画像メモリに記憶させる。なお、補正回路による補正処理として、X線の露光量や露光分布(いわゆるシェーディング)の補正や、X線画像検出器30の制御条件(駆動周波数や読み出し期間)に依存するパターンノイズ(例えば、TFTスイッチのリーク信号)の補正等を含めてもよい。
The readout circuit 43 includes an integration amplifier circuit, an A / D converter, a correction circuit, and an image memory. The integrating amplifier circuit integrates the charges output from each pixel 40 via the signal line 46, converts them into a voltage signal (image signal), and inputs it to the A / D converter. The A / D converter converts the input image signal into digital image data and inputs the digital image data to the correction circuit. The correction circuit performs offset correction, gain correction, and linearity correction on the image data, and stores the corrected image data in the image memory. As correction processing by the correction circuit, correction of X-ray exposure amount and exposure distribution (so-called shading) and pattern noise (for example, TFT) depending on the control conditions (drive frequency and readout period) of the X-ray image detector 30 are performed. Correction of the leak signal of the switch) may be included.
X線画像検出器30は、その受像面がX線の光軸Cに直交するように配置されており、典型的には、その受像部41の画素40の配列における行方向又は列方向が第1の吸収型格子31の格子ピッチ方向(x方向)と平行となるように配置される。
The X-ray image detector 30 is arranged so that its image receiving surface is orthogonal to the optical axis C of X-rays. Typically, the row direction or the column direction in the array of the pixels 40 of the image receiving unit 41 is the first. The one absorption type grating 31 is arranged so as to be parallel to the grating pitch direction (x direction).
以上のように構成された撮影部12では、第1の吸収型格子31を通過したX線によって、第1の吸収型格子31の格子構造を反映した周期的強度分布を呈するG1像が形成される。そして、このG1像は、第2の吸収型格子32との重ね合わせにより強度変調され、強度変調されたG1像がX線画像検出器30によって撮像される。第2の吸収型格子32の位置におけるG1像の周期的強度分布のパターン周期p1’と、第2の吸収型格子32の実質的な格子ピッチp2’(製造後の実質的なピッチ)とは、製造誤差や配置誤差により若干の差異が生じる。このうち、配置誤差とは、第1及び第2の吸収型格子31,32が、相対的に傾斜や回転、両者の間隔が変化することによりx方向への実質的なピッチが変化することを意味している。
In the imaging unit 12 configured as described above, a G1 image exhibiting a periodic intensity distribution reflecting the lattice structure of the first absorption type grating 31 is formed by the X-rays that have passed through the first absorption type grating 31. The The G1 image is intensity-modulated by being superimposed on the second absorption grating 32, and the intensity-modulated G1 image is captured by the X-ray image detector 30. The pattern period p 1 ′ of the periodic intensity distribution of the G1 image at the position of the second absorption type grating 32 and the substantial grating pitch p 2 ′ of the second absorption type grating 32 (substantial pitch after manufacture) Is slightly different due to manufacturing errors and placement errors. Among these, the arrangement error means that the substantial pitch in the x direction changes due to the relative inclination and rotation of the first and second absorption gratings 31 and 32 and the distance between the two changes. I mean.
G1像のパターン周期p1’と第2の吸収型格子32の格子ピッチp2’との微小な差異により、X線画像検出器30上における像コントラストはモアレ縞を含む。このモアレ縞のx方向に関する周期Tは、X線焦点18bからX線画像検出器30までの距離をLとして、次式(6)で表される。
Due to the minute difference between the pattern period p 1 ′ of the G1 image and the grating pitch p 2 ′ of the second absorption type grating 32, the image contrast on the X-ray image detector 30 includes moire fringes. The period T in the x direction of the moire fringes is expressed by the following equation (6), where L is the distance from the X-ray focal point 18b to the X-ray image detector 30.
このモアレ縞をX線画像検出器30で検出するため、画素40のx方向に関する配列ピッチPは、少なくともモアレ周期Tの整数倍でないことが必要であり、次式(7)を満たす必要がある(ここで、nは正の整数である)。
In order to detect the moire fringes with the X-ray image detector 30, the arrangement pitch P of the pixels 40 in the x direction needs to be at least not an integral multiple of the moire period T, and the following equation (7) needs to be satisfied. (Where n is a positive integer).
また、式(7)を満たす範囲において、配列ピッチPがモアレ周期Tより大きくてもモアレ縞を検出することは可能であるが、配列ピッチPはモアレ周期Tより小さいことが好ましく、次式(8)を満たすことが好ましい。これは、良質な位相コントラスト画像を得るためには、後述する位相コントラスト画像の生成過程において、モアレ縞が高いコントラストで検出されていることが好ましいためである。
Further, it is possible to detect moire fringes even if the arrangement pitch P is larger than the moire period T within the range satisfying the expression (7), but the arrangement pitch P is preferably smaller than the moire period T. It is preferable to satisfy 8). This is because, in order to obtain a high-quality phase contrast image, moire fringes are preferably detected with high contrast in the phase contrast image generation process described later.
画素40の配列ピッチPは、設計的に定められた値(一般的に100μm程度)であり変更することが困難であるため、画素40の配列ピッチPとモアレ縞の周期Tとの大小関係を調整するには、第1及び第2の吸収型格子31,32の位置調整を行い、G1像のパターン周期p1’と第2の吸収型格子32の格子ピッチp2’との少なくともいずれか一方を変更することによりモアレ縞の周期Tを変更することが好ましい。
Since the arrangement pitch P of the pixels 40 is a value determined in terms of design (generally about 100 μm) and is difficult to change, the magnitude relationship between the arrangement pitch P of the pixels 40 and the period T of moire fringes is shown. For the adjustment, the positions of the first and second absorption gratings 31 and 32 are adjusted, and at least one of the pattern period p 1 ′ of the G1 image and the grating pitch p 2 ′ of the second absorption grating 32 is set. It is preferable to change the period T of moire fringes by changing one.
図6に、モアレ縞の周期Tを変更する方法を模式的に示す。
FIG. 6 schematically shows a method of changing the period T of moire fringes.
モアレ縞の周期Tの変更は、第1及び第2の吸収型格子31,32のいずれか一方を、光軸Cを中心として相対的に回転させることにより行うことができる。例えば、第1の吸収型格子31に対して、第2の吸収型格子32を、光軸Cを中心として相対的に回転させる相対回転機構50を設ける。この相対回転機構50により、第2の吸収型格子32を角度θだけ回転させると、第2の吸収型格子32のx方向に関する実質的な格子ピッチは、「p2’」→「p2’/cosθ」と変化し、この結果、モアレ縞の周期Tが変化する(FIG.6A)。
The change of the moire fringe period T can be performed by relatively rotating one of the first and second absorption gratings 31 and 32 about the optical axis C. For example, a relative rotation mechanism 50 that rotates the second absorption grating 32 relative to the first absorption grating 31 relative to the optical axis C is provided. When the second absorption type grating 32 is rotated by the angle θ by the relative rotation mechanism 50, the substantial grating pitch in the x direction of the second absorption type grating 32 is changed from “p 2 ′” → “p 2 ′”. / Cos θ ”, and as a result, the period T of moire fringes changes (FIG. 6A).
別の例として、モアレ縞の周期Tの変更は、第1及び第2の吸収型格子31,32のいずれか一方を、光軸Cに直交し、かつy方向に沿う方向の軸を中心として相対的に傾斜させることにより行うことができる。例えば、第1の吸収型格子31に対して、第2の吸収型格子32を、光軸Cに直交し、かつy方向に沿う方向の軸を中心として相対的に傾斜させる相対傾斜機構51を設ける。この相対傾斜機構51により、第2の吸収型格子32を角度αだけ傾斜させると、第2の吸収型格子32のx方向に関する実質的な格子ピッチは、「p2’」→「p2’×cosα」と変化し、この結果、モアレ縞の周期Tが変化する(FIG.6B)。
As another example, the change in the period T of the moire fringes is performed by centering one of the first and second absorption gratings 31 and 32 on an axis perpendicular to the optical axis C and along the y direction. This can be done by relatively inclining. For example, a relative inclination mechanism 51 that inclines the second absorption type grating 32 relative to the first absorption type grating 31 about the axis in the direction orthogonal to the optical axis C and along the y direction. Provide. When the second absorption type grating 32 is inclined by the angle α by the relative inclination mechanism 51, the substantial lattice pitch in the x direction of the second absorption type grating 32 is changed from “p 2 ′” → “p 2 ′”. X cos α ”, and as a result, the period T of moire fringes changes (FIG. 6B).
更に別の例として、モアレ縞の周期Tの変更は、第1及び第2の吸収型格子31,32のいずれか一方を光軸Cの方向に沿って相対的に移動させることにより行うことができる。例えば、第1の吸収型格子31と第2の吸収型格子32との間の距離L2を変更するように、第1の吸収型格子31に対して、第2の吸収型格子32を、光軸Cの方向に沿って相対的に移動させる相対移動機構52を設ける。この相対移動機構52により、第2の吸収型格子32を光軸Cに移動量δだけ移動させると、第2の吸収型格子32の位置に投影される第1の吸収型格子31のG1像のパターン周期は、「p1’」→「p1’×(L1+L2+δ)/(L1+L2)」と変化し、この結果、モアレ縞の周期Tが変化する(FIG.6C)。
As another example, the period T of the moire fringes can be changed by relatively moving one of the first and second absorption gratings 31 and 32 along the direction of the optical axis C. it can. For example, with respect to the first absorption type grating 31, the second absorption type grating 32 is changed so as to change the distance L 2 between the first absorption type grating 31 and the second absorption type grating 32. A relative movement mechanism 52 that relatively moves along the direction of the optical axis C is provided. When the second absorption type grating 32 is moved by the movement amount δ to the optical axis C by the relative movement mechanism 52, the G1 image of the first absorption type grating 31 projected on the position of the second absorption type grating 32. The pattern period of “p 1 ′” → “p 1 ′ × (L 1 + L 2 + δ) / (L 1 + L 2 )” changes, and as a result, the period T of moire fringes changes (FIG. 6C). ).
本X線撮影装置1において、撮影部12は、上述のようにタルボ干渉計を構成するものではなく、従って距離L2を自由に設定することができるため、相対移動機構52のように距離L2の変更によりモアレ縞の周期Tを変更する機構を好適に採用することができる。モアレ縞の周期Tを変更するための第1及び第2の吸収型格子31,32の上記の変更機構(相対回転機構50、相対傾斜機構51、及び相対移動機構52)は、圧電素子等のアクチュエータにより構成することが可能である。
In the present X-ray imaging apparatus 1, the imaging unit 12 does not constitute a Talbot interferometer as described above, and therefore the distance L 2 can be freely set. Therefore, the distance L as in the relative movement mechanism 52. A mechanism for changing the period T of moire fringes by changing 2 can be suitably employed. The change mechanism (relative rotation mechanism 50, relative tilt mechanism 51, and relative movement mechanism 52) of the first and second absorption gratings 31 and 32 for changing the period T of the moiré fringes is a piezoelectric element or the like. It can be configured by an actuator.
X線照射部11と第1の吸収型格子31との間に配置された被写体台15に被写体Hを配置した場合に、G1像の周期的強度分布は、被写体Hにより変調を受け、G1像と第2の吸収型格子32との重ね合わせによるモアレ縞もまた変調を受ける。この変調量は、被写体Hによる屈折効果によって偏向したX線の角度に比例する。X線画像検出器30によって取得される画像には、モアレ縞に対応する周期パターンが含まれ、この周期パターンを含んだ画像を解析することによって、被写体Hの位相コントラスト画像を生成することができる。
When the subject H is arranged on the subject table 15 arranged between the X-ray irradiation unit 11 and the first absorption type grating 31, the periodic intensity distribution of the G1 image is modulated by the subject H, and the G1 image And the moire fringes due to the superposition of the second absorption type grating 32 are also modulated. This modulation amount is proportional to the angle of the X-ray deflected by the refraction effect by the subject H. The image acquired by the X-ray image detector 30 includes a periodic pattern corresponding to moire fringes, and a phase contrast image of the subject H can be generated by analyzing the image including the periodic pattern. .
以下、画像の解析方法について説明する。
Hereinafter, an image analysis method will be described.
〔解析方法1〕
図7は、被写体Hのx方向に関する位相シフト分布Φ(x)に応じて屈折される1つのX線を示す。 [Analysis method 1]
FIG. 7 shows one X-ray refracted according to the phase shift distribution Φ (x) of the subject H in the x direction.
図7は、被写体Hのx方向に関する位相シフト分布Φ(x)に応じて屈折される1つのX線を示す。 [Analysis method 1]
FIG. 7 shows one X-ray refracted according to the phase shift distribution Φ (x) of the subject H in the x direction.
符号55は、被写体Hが存在しない場合に直進するX線の経路を示しており、この経路55を進むX線は、第1及び第2の吸収型格子31,32を通過してX線画像検出器30に入射する。符号56は、被写体Hが存在する場合に、被写体Hにより屈折されて偏向したX線の経路を示している。この経路56を進むX線は、第1の吸収型格子31を通過した後、第2の吸収型格子32より遮蔽される。
Reference numeral 55 indicates an X-ray path that goes straight when the subject H does not exist. The X-ray that travels along the path 55 passes through the first and second absorption gratings 31 and 32 and is an X-ray image. The light enters the detector 30. Reference numeral 56 indicates an X-ray path refracted and deflected by the subject H when the subject H exists. X-rays traveling along this path 56 are shielded by the second absorption type grating 32 after passing through the first absorption type grating 31.
被写体Hの位相シフト分布Φ(x)は、被写体Hの屈折率分布をn(x,z)、zをX線の進む方向として、次式(9)で表される。
The phase shift distribution Φ (x) of the subject H is expressed by the following formula (9), where n (x, z) is the refractive index distribution of the subject H and z is the direction in which the X-ray travels.
第1の吸収型格子31から第2の吸収型格子32の位置に投射されたG1像は、被写体HでのX線の屈折により、その屈折角φに応じた量だけx方向に変位することになる。この変位量Δxは、X線の屈折角φが微小であることに基づいて、近似的に次式(10)で表される。
The G1 image projected from the first absorptive grating 31 to the position of the second absorptive grating 32 is displaced in the x direction by an amount corresponding to the refraction angle φ due to refraction of X-rays at the subject H. become. This displacement amount Δx is approximately expressed by the following equation (10) based on the fact that the refraction angle φ of X-rays is very small.
ここで、屈折角φは、X線波長λと被写体Hの位相シフト分布Φ(x)を用いて、式(11)で表される。
Here, the refraction angle φ is expressed by Expression (11) using the X-ray wavelength λ and the phase shift distribution Φ (x) of the subject H.
このように、被写体HでのX線の屈折によるG1像の変位量Δxは、被写体Hの位相シフト分布Φ(x)に関連している。そして、この変位量Δxは、画像データの各画素の信号の位相ズレ量ψ(被写体Hがある場合とない場合とでの信号の位相差)に、次式(12)のように関連している。
Thus, the displacement amount Δx of the G1 image due to the refraction of X-rays at the subject H is related to the phase shift distribution Φ (x) of the subject H. This displacement amount Δx is related to the phase shift amount ψ of the signal of each pixel of the image data (the signal phase difference between when the subject H is present and when it is not present) as shown in the following equation (12). Yes.
したがって、各画素の信号の位相ズレ量ψを求めることにより、式(12)から屈折角φが求まり、式(11)を用いて位相シフト分布Φ(x)の微分量が求まるから、これをxについて積分することにより、被写体Hの位相シフト分布Φ(x)、すなわち被写体Hの位相コントラスト画像を生成することができる。本X線撮影装置1では、上記の位相ズレ量ψを、以下に説明する縞走査法を用いて算出する。
Accordingly, by obtaining the phase shift amount ψ of the signal of each pixel, the refraction angle φ is obtained from the equation (12), and the differential amount of the phase shift distribution Φ (x) is obtained using the equation (11). By integrating with respect to x, the phase shift distribution Φ (x) of the subject H, that is, the phase contrast image of the subject H can be generated. In the X-ray imaging apparatus 1, the phase shift amount ψ is calculated using a fringe scanning method described below.
縞走査法では、第1及び第2の吸収型格子31,32のうちの一方の格子を、その格子が位置する面内においてステップ的に並進移動させ、G1像の周期的強度分布に対する第2の吸収型格子32のX線遮蔽部32bの周期的配列の位相を変化させながら撮影を行う。本X線撮影装置1では、走査機構33(図1参照)により第2の吸収型格子32を移動させているが、第1の吸収型格子31を移動させてもよい。
In the fringe scanning method, one of the first and second absorption- type gratings 31 and 32 is translated in a stepwise manner within the plane where the grating is positioned, and the second is applied to the periodic intensity distribution of the G1 image. The imaging is performed while changing the phase of the periodic arrangement of the X-ray shielding portions 32b of the absorption type grating 32. In the present X-ray imaging apparatus 1, the second absorption type grating 32 is moved by the scanning mechanism 33 (see FIG. 1), but the first absorption type grating 31 may be moved.
第2の吸収型格子32の移動に伴ってモアレ縞が移動し、第2の吸収型格子32の格子ピッチ方向に関する並進距離が、第2の吸収型格子32の格子ピッチの1周期(格子ピッチp2)に達すると(すなわち、位相変化が2πに達すると)、モアレ縞は元の位置に戻る。このようなモアレ縞の変化を、第2の吸収型格子32を移動させながらX線画像検出器30で撮像し、得られた複数の画像データから画素毎に複数個の信号値を取得し、演算処理部22で演算処理することによって各画素の信号の位相ズレ量ψを得る。
Moire fringes move with the movement of the second absorption grating 32, and the translational distance in the grating pitch direction of the second absorption grating 32 is one period of the grating pitch of the second absorption grating 32 (the grating pitch). When p 2 ) is reached (ie when the phase change reaches 2π), the moire fringes return to their original positions. Such a change in moire fringes is captured by the X-ray image detector 30 while moving the second absorption grating 32, and a plurality of signal values are obtained for each pixel from the obtained plurality of image data. A phase shift amount ψ of the signal of each pixel is obtained by performing arithmetic processing in the arithmetic processing unit 22.
図8は、第2の吸収型格子32を、その格子ピッチ方向(x方向)に、格子ピッチp2をM(2以上の整数)個に分割した走査ピッチ(p2/M)ずつ移動させる様子を模式的に示す。
In FIG. 8, the second absorption type grating 32 is moved in the grating pitch direction (x direction) by the scanning pitch (p 2 / M) obtained by dividing the grating pitch p 2 into M (integer of 2 or more). A state is shown typically.
走査機構33は、k=0,1,2,・・・,M-1のM個の各走査位置に、第2の吸収型格子32を順に並進移動させる。なお、同図では、第2の吸収型格子32の初期位置を、被写体Hが存在しない場合における第2の吸収型格子32の位置でのG1像の暗部が、X線遮蔽部32bにほぼ一致する位置(k=0)としているが、この初期位置は、k=0,1,2,・・・,M-1のうちいずれの位置としてもよい。
The scanning mechanism 33 translates the second absorption type grating 32 in order to M scanning positions of k = 0, 1, 2,..., M−1. In the same figure, the initial position of the second absorption grating 32 is the same as the dark part of the G1 image at the position of the second absorption grating 32 when the subject H is not present. The initial position is k = 0, 1, 2,..., M−1.
まず、k=0の位置では、主として、被写体Hにより屈折されなかったX線が第2の吸収型格子32を通過する。次に、k=1,2,・・・と順に第2の吸収型格子32を移動させていくと、第2の吸収型格子32を通過するX線は、被写体Hにより屈折されなかったX線の成分が減少する一方で、被写体Hにより屈折されたX線の成分が増加する。特に、k=M/2では、主として、被写体Hにより屈折されたX線のみが第2の吸収型格子32を通過する。k=M/2を超えると、逆に、第2の吸収型格子32を通過するX線は、被写体Hにより屈折されたX線の成分が減少する一方で、被写体Hにより屈折されなかったX線の成分が増加する。k=0,1,2,・・・,M-1の各位置においてX線画像検出器30で撮像すると、画素毎にM個の信号値が得られる。
First, at the position of k = 0, X-rays that are not refracted by the subject H mainly pass through the second absorption type grating 32. Next, when the second absorption grating 32 is moved in order of k = 1, 2,..., The X-rays passing through the second absorption grating 32 are not refracted by the subject H. While the line component decreases, the X-ray component refracted by the subject H increases. In particular, at k = M / 2, mainly only the X-rays refracted by the subject H pass through the second absorption type grating 32. When k = M / 2 is exceeded, on the contrary, the X-ray component that is refracted by the subject H decreases in the X-rays that pass through the second absorption grating 32, while the X-ray that is not refracted by the subject H. The line component increases. When images are taken by the X-ray image detector 30 at each position of k = 0, 1, 2,..., M−1, M signal values are obtained for each pixel.
なお、図8に示す例においては、第2の吸収型格子32を、その格子ピッチ方向(x方向)に移動させるものとして説明したが、格子ピッチ方向に関する変位を伴う限りにおいて、図9に示すように、第2の吸収型格子32を、その格子ピッチ方向(x方向)と交差する方向に移動させるようにしてもよい。第2の吸収型格子32を、その格子ピッチ方向と交差する方向に移動させることによって、格子ピッチ方向に関する並進距離が格子ピッチp2に達するまでの走査方向に沿った並進距離は、格子ピッチp2より大きくなる。よって、走査方向に沿った並進距離をM個に分割した走査ピッチもまた大きくなり、第2の吸収型格子32の移動誤差に対する耐性が高まる。被写体Hを透過することで生じるX線の屈折は僅か数μradであり、この屈折によって生じるモアレ縞の変調、及び上述した縞走査法によってモアレ縞を解析して得られる信号の位相変化も僅かである。このような僅かな変化を計測する場合において、第2の吸収型格子32の移動誤差に対する耐性が高められることにより、被写体Hの位相情報の検出精度を高めることができる。
In the example shown in FIG. 8, the second absorption grating 32 has been described as being moved in the grating pitch direction (x direction). However, as long as displacement in the grating pitch direction is involved, the second absorption grating 32 is shown in FIG. As described above, the second absorption type grating 32 may be moved in a direction intersecting with the grating pitch direction (x direction). By moving the second absorption type grating 32 in a direction crossing the grating pitch direction, the translation distance along the scanning direction until the translation distance in the grating pitch direction reaches the grating pitch p 2 is equal to the grating pitch p. Greater than 2 . Therefore, the scanning pitch obtained by dividing the translation distance along the scanning direction into M pieces is also increased, and resistance to movement errors of the second absorption type grating 32 is increased. The refraction of the X-ray generated by passing through the subject H is only a few μrad, and the modulation of the moire fringe caused by this refraction and the phase change of the signal obtained by analyzing the moire fringe by the above-described fringe scanning method are also slight. is there. In the case of measuring such a slight change, it is possible to improve the detection accuracy of the phase information of the subject H by increasing the resistance against the movement error of the second absorption grating 32.
以下に、このM個の信号値から各画素の信号の位相ズレ量ψを算出する方法を説明する。
Hereinafter, a method of calculating the phase shift amount ψ of the signal of each pixel from the M signal values will be described.
第2の吸収型格子32が位置kにあるときの各画素の信号値をIk(x)とすると、Ik(x)は、次式(13)で表される。
When the signal value of each pixel when the second absorption type grating 32 is at the position k is I k (x), I k (x) is expressed by the following equation (13).
ここで、xは、各画素のx方向に関する座標であり、A0は入射X線の強度であり、Anは信号のコントラストに対応する値である(ここで、nは正の整数である)。また、φ(x)は、屈折角φを画素の座標xの関数として表したものである。
Here, x is a coordinate in the x direction of each pixel, A 0 is the intensity of the incident X-ray, and An is a value corresponding to the contrast of the signal (where n is a positive integer). ). Φ (x) represents the refraction angle φ as a function of the pixel coordinate x.
次いで、次式(14)の関係式を用いると、屈折角φ(x)は、次式(15)のように表される。
Next, using the relational expression of the following expression (14), the refraction angle φ (x) is expressed as the following expression (15).
ここで、arg[ ]は、偏角の抽出を意味しており、各画素の信号の位相ズレ量ψに対応する。したがって、画素毎に得られたM個の信号値から、式(15)に基づいて各画素の信号の位相ズレ量ψを算出することにより、屈折角φ(x)が求められる。
Here, arg [] means extraction of the declination, and corresponds to the phase shift amount ψ of the signal of each pixel. Therefore, the refraction angle φ (x) is obtained by calculating the phase shift amount ψ of the signal of each pixel from the M signal values obtained for each pixel based on the equation (15).
図10は、縞走査に伴って変化する一つの画素の信号波形を示す。
FIG. 10 shows the signal waveform of one pixel that changes with the fringe scanning.
画素毎に得られるM個の信号値は、第2の吸収型格子32の位置kに対して、格子ピッチp2の周期で周期的に変化する。図10中の破線は、被写体Hが存在しない場合の信号波形を示しており、図10中の実線は、被写体Hが存在する場合の信号波形を示している。この両者の波形の位相差が各画素の信号の位相ズレ量ψに対応する。
The M signal values obtained for each pixel periodically change with the period of the grating pitch p 2 with respect to the position k of the second absorption type grating 32. A broken line in FIG. 10 indicates a signal waveform when the subject H does not exist, and a solid line in FIG. 10 indicates a signal waveform when the subject H exists. The phase difference between the two waveforms corresponds to the phase shift amount ψ of the signal of each pixel.
そして、屈折角φ(x)は、上記式(11)で示したように位相シフト分布Φ(x)の微分に対応するため、屈折角φ(x)をx軸に沿って積分することにより、位相シフト分布Φ(x)が得られる。なお、上記の説明では、画素のy方向に関するy座標を考慮していないが、各y座標について同様の演算を行うことにより、x方向及びy方向における2次元的な位相シフト分布Φ(x,y)が得られる。以上の演算は、演算処理部22により行われ、演算処理部22は、位相シフト分布Φ(x,y)を位相コントラスト画像として記憶部23に記憶させる。
Since the refraction angle φ (x) corresponds to the differentiation of the phase shift distribution Φ (x) as shown in the above equation (11), the refraction angle φ (x) is integrated along the x axis. A phase shift distribution Φ (x) is obtained. In the above description, the y-coordinate regarding the y-direction of the pixel is not taken into consideration. However, by performing the same calculation for each y-coordinate, a two-dimensional phase shift distribution Φ (x, y) is obtained. The above calculation is performed by the calculation processing unit 22, and the calculation processing unit 22 stores the phase shift distribution Φ (x, y) in the storage unit 23 as a phase contrast image.
〔解析方法2〕
図11は、X線撮影装置1における位相コントラスト画像の生成方法の他の例を示す。 [Analysis method 2]
FIG. 11 shows another example of a method for generating a phase contrast image in theX-ray imaging apparatus 1.
図11は、X線撮影装置1における位相コントラスト画像の生成方法の他の例を示す。 [Analysis method 2]
FIG. 11 shows another example of a method for generating a phase contrast image in the
以下に説明する方法においては、モアレ縞に対して交差する方向に並ぶ複数の画素を一単位として解析を行い、一つの画像データから各画素の信号の位相ズレ量ψを算出する。
In the method described below, a plurality of pixels arranged in a direction intersecting with the moire fringe are analyzed as a unit, and the phase shift amount ψ of the signal of each pixel is calculated from one image data.
図11に示す例において、第1及び第2の吸収型格子31,32が、光軸Cを中心として角度θだけ相対的に回転して配置されており、G1像及び第2の吸収型格子32が角度θだけ相対的に回転され、y方向に周期性を有するモアレ縞が生じている。そこで、モアレ縞に対して交差するy方向に並ぶ複数の画素を一単位Uとして解析を行う。図11に示す例においては、y方向に並ぶ5つの画素を一単位Uとしている。
In the example shown in FIG. 11, the first and second absorption type gratings 31 and 32 are arranged so as to be relatively rotated by an angle θ about the optical axis C, and the G1 image and the second absorption type grating are arranged. 32 is relatively rotated by an angle θ, and moire fringes having periodicity in the y direction are generated. Therefore, the analysis is performed with a plurality of pixels arranged in the y direction intersecting the moire fringes as one unit U. In the example shown in FIG. 11, five pixels arranged in the y direction are defined as one unit U.
上述した通り、G1像は、被写体HでのX線の屈折により、その屈折角φに応じた量だけx方向に変位し、G1像のx方向の変位に伴ってモアレ縞はy方向に変位することになる。図12に示すように、モアレ縞の変位に伴い、単位毎に、その単位を構成する画素群の信号値を補間してなる信号波形の位相が変化する。被写体Hが存在しない場合の信号波形(FIG.12A)と、被写体Hが存在する場合の信号波形(FIG.12B)との両者の波形の位相差が、その単位に含まれる画素の信号の位相ズレ量ψに対応する。
As described above, the G1 image is displaced in the x direction by an amount corresponding to the refraction angle φ due to the refraction of X-rays at the subject H, and the moire fringes are displaced in the y direction as the G1 image is displaced in the x direction. Will do. As shown in FIG. 12, with the displacement of the moire fringes, the phase of the signal waveform obtained by interpolating the signal value of the pixel group constituting the unit changes for each unit. The phase difference between the waveform of the signal waveform (FIG. 12A) when the subject H is not present and the signal waveform (FIG. 12B) when the subject H is present is the phase of the pixel signal included in the unit. This corresponds to the displacement amount ψ.
そして、解析を行う画素群の単位を例えばy方向に1画素ずつずらしながら、単位毎に上記の解析を行うことによって、各画素の信号の位相ズレ量ψを得ることができる。即ち、画素40のy方向の並びにおけるk番目の画素40の信号の位相ズレ量ψは、k番目の画素40の信号値をIkとして、[Ik,Ik+1,Ik+2,Ik+3,Ik+4]の5個の信号値を用い、k+1番目の画素40の信号の位相ズレ量ψは、[Ik+1,Ik+2,Ik+3,Ik+4,Ik+5]の5個の信号値を用いて、それぞれ得ることができる。なお、画素群の単位を、一単位とする5画素以下の範囲でy方向に複数画素ずつずらしながら、単位毎に上記の解析を行うこともできる。例えば2画素ずつずらすものとして、k番目及びk+1番目の各画素40の信号の位相ズレ量ψは、[Ik,Ik+1,Ik+2,Ik+3,Ik+4]の5個の信号値を用い、k+2番目及びk+3番目の各画素40の信号の位相ズレ量ψは、[Ik+2,Ik+3,Ik+4,Ik+5,Ik+6]の5個の信号値を用いて、それぞれ得ることができる。
Then, the phase shift amount ψ of the signal of each pixel can be obtained by performing the above analysis for each unit while shifting the unit of the pixel group to be analyzed, for example, by one pixel in the y direction. That is, the phase shift amount ψ of the k-th pixel 40 of the signal at the row of the y direction of pixels 40, the signal value of the k-th pixel 40 as I k, [I k, I k + 1, I k + 2, I k + 3, 5 signal values of I k + 4 ] and 5 signal values of [I k + 1 , I k + 2 , I k + 3 , I k + 4 , I k + 5 ] are used as the phase shift amount ψ of the signal of the (k + 1) th pixel 40. Can be obtained respectively. Note that the above analysis can be performed for each unit while shifting the unit of the pixel group by a plurality of pixels in the y direction within a range of 5 pixels or less as one unit. For example, assuming that each pixel is shifted by two pixels, the phase shift amount ψ of the signal of each of the kth and k + 1th pixels 40 uses five signal values of [I k , I k + 1 , I k + 2 , I k + 3 , I k + 4 ]. , K + 2 and k + 3 pixels 40 can be obtained by using five signal values of [I k + 2 , I k + 3 , I k + 4 , I k + 5 , I k + 6 ]. .
各画素の信号の位相ズレ量ψから式(12)を用いて屈折角φが求まり、そして式(11)を用いて位相シフト分布Φ(x)の微分量が求まり、これをxについて積分することにより、被写体Hの位相シフト分布Φ(x)、すなわち被写体Hの位相コントラスト画像を生成する。
The refraction angle φ is obtained from the phase shift amount ψ of the signal of each pixel using the equation (12), and the differential amount of the phase shift distribution Φ (x) is obtained using the equation (11), and this is integrated with respect to x. Thus, the phase shift distribution Φ (x) of the subject H, that is, the phase contrast image of the subject H is generated.
なお、y方向に並ぶ3画素以上を一単位としてモアレ縞を解像すれば、上記の解析は可能である。よって、y方向に関するモアレ周期Tとy方向に関する画素40のピッチPとの満たすべき関係は、G1像を回転させる場合には次式(16)となり、第2の吸収型格子32を回転させる場合には次式(17)となる。
It should be noted that the above analysis is possible if the moire fringes are resolved with 3 pixels or more arranged in the y direction as a unit. Therefore, the relationship to be satisfied between the moire period T in the y direction and the pitch P of the pixels 40 in the y direction is expressed by the following expression (16) when the G1 image is rotated, and the second absorption type grating 32 is rotated. Is given by the following equation (17).
なお、一単位とする画素数は、それらの画素の並びがy方向に関するモアレ周期Tの少なくとも一周期の区間に亘る画素数とすることが好ましい。ここで、y方向に関するモアレ周期Tがy方向に関する画素40の配列ピッチPのほぼM倍(Mは整数)になるように設定し、M個の画素40を一単位とした場合に、画素40のy方向の並びにおけるk番目の画素40の信号値をIkとして、Ik~Ik+M-1のM個の信号値は、上述した縞走査法において第1及び第2の吸収型格子31,32のうちの一方の格子を、その格子ピッチをM個に分割した走査ピッチで格子ピッチ方向に移動させた際に、k番目の画素40について取得されるM個の信号値と等価である。
Note that the number of pixels as a unit is preferably the number of pixels over which at least one period of the moire period T in the y direction is arranged. Here, when the moire period T in the y direction is set to be approximately M times the arrangement pitch P of the pixels 40 in the y direction (M is an integer), and the M pixels 40 are taken as one unit, the pixel 40 The signal values of the k-th pixel 40 in the y-direction array are I k , and the M signal values of I k to I k + M−1 are the first and second absorption gratings 31 in the fringe scanning method described above. , 32 is equivalent to M signal values acquired for the kth pixel 40 when the grid pitch is moved in the grid pitch direction at a scan pitch obtained by dividing the grid pitch into M pieces. .
図13は、図11の解析方法の変形例を示す。
FIG. 13 shows a modification of the analysis method of FIG.
図13に示す例においては、第2の吸収型格子32の格子ピッチp2がG1像のピッチp1’と異なり、x方向に周期性を有するモアレ縞が生じている。第2の吸収型格子32の格子ピッチp2とG1像のピッチp1’とを異ならせるにあたっては、例えば第1及び第2の吸収型格子31,32のいずれか一方を光軸Cの方向に沿って相対的に移動させてもよいし、第1及び第2の吸収型格子31,32の各々の格子ピッチを調整してもよい。
In the example shown in FIG. 13, the grating pitch p 2 of the second absorption type grating 32 is different from the pitch p 1 ′ of the G1 image, and moire fringes having periodicity in the x direction are generated. In order to make the grating pitch p 2 of the second absorption grating 32 different from the pitch p 1 ′ of the G1 image, for example, one of the first and second absorption gratings 31 and 32 is placed in the direction of the optical axis C. May be moved relative to each other, or the grating pitch of each of the first and second absorption gratings 31 and 32 may be adjusted.
そして、モアレ縞に対して交差するx方向に並ぶ複数の画素を一単位Uとして上記の解析を行う。図13に示す例においては、x方向に並ぶ4つの画素を一単位Uとしているが、本例においても、x方向に並ぶ3画素以上を一単位としてモアレ縞を解像すれば上記の解析は可能であり、x方向に関するモアレ縞の周期Tとx方向に関する画素40のピッチPとの満たすべき関係は、次式(18)となる。
Then, the above analysis is performed with a plurality of pixels arranged in the x direction intersecting the moire fringes as one unit U. In the example shown in FIG. 13, four pixels arranged in the x direction are set as one unit U. However, in this example, if the moire fringes are resolved using three or more pixels arranged in the x direction as one unit, the above analysis is performed. The relationship to be satisfied between the period T of moire fringes in the x direction and the pitch P of the pixels 40 in the x direction is expressed by the following equation (18).
図14は、図11の解析方法の他の変形例を示す。
FIG. 14 shows another modification of the analysis method of FIG.
図14に示す例においては、第2の吸収型格子32の格子ピッチp2がG1像のピッチp1’と異なり、更に、G1像に対して第2の吸収型格子32が相対的に回転して配置され、x方向及びy方向と交差する方向に周期性を有するモアレ縞が生じている。
In the example shown in FIG. 14, the grating pitch p 2 of the second absorption grating 32 is different from the pitch p 1 ′ of the G1 image, and the second absorption grating 32 rotates relative to the G1 image. Moire fringes having periodicity are generated in the direction intersecting the x direction and the y direction.
上述の通り、モアレ縞に対して交差する方向に並ぶ3画素以上を一単位としてモアレ縞を解像すれば、単位毎に、その単位に含まれる画素の信号の位相ズレ量ψを算出することができるので、本例においては、x方向に並ぶ3画素以上の複数の画素を一単位Uとして解析を行うこともできるし(FIG.14A)、y方向に並ぶ3画素以上の複数の画素を一単位Uとして解析を行うこともできる(FIG.14B)。
As described above, if the moire fringe is resolved with three or more pixels arranged in the direction intersecting the moire fringe as a unit, the phase shift amount ψ of the signal of the pixel included in the unit is calculated for each unit. Therefore, in this example, the analysis can be performed with a plurality of pixels of 3 pixels or more arranged in the x direction as one unit U (FIG. 14A), or a plurality of pixels of 3 pixels or more arranged in the y direction can be analyzed. Analysis can also be performed as one unit U (FIG. 14B).
図15は、図11の解析方法の他の変形例を示す。
FIG. 15 shows another modification of the analysis method of FIG.
図11に示す例においては、G1像の周期的強度分布のパターン周期方向(x方向)とX線画像検出器30における画素40の配列における行方向又は列方向とが一致しているが、図15に示す例においては、第1の吸収型格子31とX線画像検出器30とが、光軸Cを中心として相対的に回転して配置されることにより、G1像の周期的強度分布のパターン周期方向(x方向)に対して、画素40の配列における行方向及び列方向がいずれも交差している。この場合にも、上述の通り、モアレ縞に対して交差する方向に並ぶ3画素以上の複数の画素を一単位Uとしてモアレ縞を解像すれば、単位毎に、その単位に含まれる画素の信号の位相ズレ量ψを算出することができる。
In the example shown in FIG. 11, the pattern period direction (x direction) of the periodic intensity distribution of the G1 image and the row direction or the column direction in the array of the pixels 40 in the X-ray image detector 30 match. In the example shown in FIG. 15, the first absorption type grating 31 and the X-ray image detector 30 are arranged so as to rotate relative to each other about the optical axis C, so that the periodic intensity distribution of the G1 image is obtained. Both the row direction and the column direction in the array of the pixels 40 intersect with the pattern periodic direction (x direction). Also in this case, as described above, if the moire fringe is resolved with a plurality of pixels of three or more pixels arranged in the direction intersecting the moire fringe as one unit U, the pixels included in the unit are determined for each unit. The amount of phase shift ψ of the signal can be calculated.
以上の解析方法2によれば、一つの周期パターン画像から位相コントラスト画像を生成することができ、よって一度の撮影で済むため、複数回の撮影の間の第1の吸収型格子31又は第2の吸収型格子32の移動、及び高精度が要求されるその走査機構33が不要となる。そのため、撮影ワークフローの向上と装置の簡易化が可能になる。また、各撮影間の被写体の移動に起因する画質低下を解消することができる。
According to the analysis method 2 described above, a phase contrast image can be generated from one periodic pattern image, and thus only one imaging is required. Therefore, the first absorption type grating 31 or the second between multiple imagings. Therefore, the movement of the absorption type grating 32 and the scanning mechanism 33 that requires high accuracy are not required. Therefore, it is possible to improve the shooting workflow and simplify the apparatus. In addition, it is possible to eliminate the deterioration in image quality caused by the movement of the subject between each photographing.
〔解析方法3〕
図16は、X線撮影装置1における位相コントラスト画像の生成方法の他の例を示す。 [Analysis method 3]
FIG. 16 shows another example of a method for generating a phase contrast image in theX-ray imaging apparatus 1.
図16は、X線撮影装置1における位相コントラスト画像の生成方法の他の例を示す。 [Analysis method 3]
FIG. 16 shows another example of a method for generating a phase contrast image in the
以下に説明する方法においては、フーリエ変換及び逆フーリエ変換を用いて画像の周期パターンの解析を行い、位相コントラスト画像を生成する。
In the method described below, a periodic pattern of an image is analyzed using Fourier transform and inverse Fourier transform to generate a phase contrast image.
G1像と第2の吸収型格子32との重ね合わせによって形成されるモアレ縞に対応した画像の周期パターンは次式(19)で表すことができ、式(19)は次式(20)に書き換えることができる。
The periodic pattern of the image corresponding to the moire fringes formed by superimposing the G1 image and the second absorption type grating 32 can be expressed by the following equation (19), and the equation (19) is expressed by the following equation (20). Can be rewritten.
式(19)において、a(x,y)はバックグラウンドを表し、b(x,y)は周期パターンの基本周期に対応した空間周波数成分の振幅を表し、(f0x、f0y)は周期パターンの基本周期を表す。また式(20)において、c(x,y)は次式(21)で表される。
In Expression (19), a (x, y) represents the background, b (x, y) represents the amplitude of the spatial frequency component corresponding to the basic period of the periodic pattern, and (f 0x, f 0y ) represents the period. Represents the basic period of the pattern. In the formula (20), c (x, y) is represented by the following formula (21).
従って、c(x,y)又はc*(x,y)の成分を取り出すことによって屈折角φ(x,y)の情報を得ることができる。ここで、式(20)はフーリエ変換によって次式(22)となる。
Therefore, information on the refraction angle φ (x, y) can be obtained by extracting the component of c (x, y) or c * (x, y). Here, equation (20) becomes the following equation (22) by Fourier transform.
式(22)において、F(fx,fy)、A(fx,fy)、C(fx,fy)は、それぞれf(x,y)、a(x,y)、c(x,y)に対する2次元のフーリエ変換である。
In the formula (22), F (f x , f y), A (f x, f y), C (f x, f y) , respectively f (x, y), a (x, y), c It is a two-dimensional Fourier transform for (x, y).
第1及び第2の吸収型格子31,32のような1次元格子を使用した場合に、画像の空間周波数スペクトルには、図16に示すように、少なくとも、A(fx,fy)に由来するピークと、これを挟んでC(fx,fy)及びC*(fx,fy)に由来する周期パターンの基本周期に対応した空間周波数成分のピークとの3つのピークが生じる。A(fx,fy)に由来するピークは原点に、また、C(fx,fy)及びC*(fx,fy)に由来するピークは(±f0x,±f0y)(複合同順)の位置に生じる。
When one-dimensional gratings such as the first and second absorption gratings 31 and 32 are used, the spatial frequency spectrum of the image has at least A (f x , f y ) as shown in FIG. a peak derived from, C (f x, f y ) and C * (f x, f y ) 3 peaks and the peak of the spatial frequency component corresponding to the fundamental period of the periodic pattern from the results across this . A (f x, f y) peak derived from the origin, also, C (f x, f y ) and C * (f x, f y ) peak derived from the (± f 0x, ± f 0y ) It occurs at the position of (combined same order).
画像の空間周波数スペクトルから屈折角φ(x、y)を得るには、周期パターンの基本周期に対応する空間周波数成分のピーク周波数を含む領域を切り出し、ピーク周波数が周波数空間の原点に重なるように切り出した領域を移動させ、逆フーリエ変換を行う。そして、逆フーリエ変換によって得られる複素数情報から屈折角φ(x,y)を得ることができる。屈折角φ(x,y)から位相コントラスト画像を生成する方法については、上述した縞走査法と同様である。
In order to obtain the refraction angle φ (x, y) from the spatial frequency spectrum of the image, a region including the peak frequency of the spatial frequency component corresponding to the basic period of the periodic pattern is cut out so that the peak frequency overlaps the origin of the frequency space. Move the clipped area and perform inverse Fourier transform. Then, the refraction angle φ (x, y) can be obtained from the complex number information obtained by the inverse Fourier transform. The method for generating the phase contrast image from the refraction angle φ (x, y) is the same as the above-described fringe scanning method.
以上の解析方法3によれば、一つの周期パターン画像から位相コントラスト画像を生成することができ、よって一度の撮影で済むため、複数回の撮影の間の第1の吸収型格子31又は第2の吸収型格子32の移動、及び高精度が要求されるその走査機構33が不要となる。そのため、撮影ワークフローの向上と装置の簡易化が可能になる。また、各撮影間の被写体の移動に起因する画質低下を解消することができる。
According to the analysis method 3 described above, a phase contrast image can be generated from one periodic pattern image, and thus only one imaging is required. Therefore, the first absorption type grating 31 or the second between multiple imagings. Therefore, the movement of the absorption type grating 32 and the scanning mechanism 33 that requires high accuracy are not required. Therefore, it is possible to improve the shooting workflow and simplify the apparatus. In addition, it is possible to eliminate the deterioration in image quality caused by the movement of the subject between each photographing.
上述した解析方法1~3によれば、第1の吸収型格子31の格子ピッチ方向であるx方向に関する屈折角φ、つまりは位相シフト分布Φの微分が得られ、この位相シフト分布Φの微分に基づいて得られる位相コントラスト画像には、第1の吸収型格子31の格子ピッチ方向に交差する被写体Hの縁部が描出され、特に第1の吸収型格子31の格子ピッチ方向に略直交する被写体Hの縁部が明瞭に描出される。即ち、被写体Hの配置は、第1の吸収型格子31の格子ピッチ方向の制約を受けることとなる。
According to the analysis methods 1 to 3 described above, the refraction angle φ with respect to the x direction which is the lattice pitch direction of the first absorption type grating 31, that is, the differential of the phase shift distribution Φ is obtained, and the differential of the phase shift distribution Φ is obtained. In the phase contrast image obtained based on the above, the edge of the subject H that intersects the grating pitch direction of the first absorption type grating 31 is depicted, and in particular, substantially perpendicular to the grating pitch direction of the first absorption type grating 31. The edge of the subject H is clearly depicted. That is, the arrangement of the subject H is restricted by the lattice pitch direction of the first absorption-type lattice 31.
図17は、アーム部材61の配置を第1の吸収型格子31との関係において示す。
FIG. 17 shows the arrangement of the arm member 61 in relation to the first absorption type lattice 31.
上述の通り、X線照射部11及び撮影部12並びに被写体台15は、スタンド13のアーム部材61にいずれも支持されており、アーム部材61が延びる鉛直方向(z方向)に上側からX線照射部11、被写体台15、撮影部12の順に配置されている。
As described above, the X-ray irradiation unit 11, the imaging unit 12, and the subject table 15 are all supported by the arm member 61 of the stand 13, and X-ray irradiation is performed from above in the vertical direction (z direction) in which the arm member 61 extends. The unit 11, the subject table 15, and the imaging unit 12 are arranged in this order.
そして、第1の吸収型格子31を有する撮影部12は、第1の吸収型格子31のX線遮蔽部31bの延在方向(y方向)の縁がアーム部材61に添うようにして、アーム部材61に取り付けられている。アーム部材61は、被写体Hが載置される被写体台15の載置面を含む平面A、即ち被写体Hの配置位置に広がる平面Aにおいて、第1の吸収型格子31をその格子ピッチ方向(x方向)に延長した領域a1と鉛直方向に重なる領域A1を外れ、第1の吸収型格子31をそのX線遮蔽部31bの延在方向(y方向)に延長した領域a2と鉛直方向に重なる領域A2を通って、鉛直方向に延在する。換言すれば、アーム部材61は、被写体台15の載置面を第1の吸収型格子31の格子ピッチ方向(x方向)に延長した領域を外れ、被写体台15の載置面を第1の吸収型格子31のX線遮蔽部31bの延在方向(y方向)に延長した領域を通って、鉛直方向に延在する。更に換言すれば、第1の吸収型格子31の格子ピッチ方向と第2の吸収型格子32の格子ピッチ方向とは略一致していることから、アーム部材61は、被写体台15の載置面を第2の吸収型格子32の格子ピッチ方向に延長した領域を外れ、被写体台15の載置面を第2の吸収型格子32のX線遮蔽部32bの延在方向に延長した領域を通って、鉛直方向に延在する。
The imaging unit 12 having the first absorption type grating 31 is arranged so that the edge in the extending direction (y direction) of the X-ray shielding part 31 b of the first absorption type grating 31 follows the arm member 61. It is attached to the member 61. The arm member 61 places the first absorption grating 31 in the grating pitch direction (x in the plane A including the placement surface of the subject table 15 on which the subject H is placed, that is, the plane A extending to the arrangement position of the subject H. Area A1 that extends in the vertical direction and the area A1 that extends in the vertical direction, and that overlaps the area a2 in which the first absorption grating 31 extends in the extending direction (y direction) of the X-ray shielding portion 31b in the vertical direction. It extends in the vertical direction through A2. In other words, the arm member 61 deviates from a region where the mounting surface of the subject table 15 is extended in the lattice pitch direction (x direction) of the first absorption type grating 31, and the mounting surface of the subject table 15 is moved to the first surface. The absorption grating 31 extends in the vertical direction through a region extending in the extending direction (y direction) of the X-ray shielding portion 31b. In other words, since the grating pitch direction of the first absorption type grating 31 and the grating pitch direction of the second absorption type grating 32 substantially coincide with each other, the arm member 61 has the mounting surface of the subject table 15. Is removed from the region extending in the lattice pitch direction of the second absorption type grating 32, and passes through the region where the mounting surface of the subject table 15 is extended in the extending direction of the X-ray shielding portion 32 b of the second absorption type grating 32. Extending in the vertical direction.
図18は、被写体Hの配置の一例を示す。
FIG. 18 shows an example of the arrangement of the subject H.
以上のように構成されたX線撮影装置1においては、第1の吸収型格子31の格子ピッチ方向(x方向)に関して、被写体台15の先にアーム部材61が位置しない。よって、腕や脚などの比較的長尺な被写体Hを、第1の吸収型格子31の格子ピッチ方向に沿って配置することができる。それにより、例えば図18に示す膝関節の撮影においては、膝関節を構成する大腿骨B1及び脛骨B2の各々の対向面を覆う軟骨、並びに関節裂隙を満たす関節液の境界が、第1の吸収型格子31の格子ピッチ方向(x方向)に略直交するように配置され、軟骨の縁部が位相コントラスト画像に明瞭に描出される。
In the X-ray imaging apparatus 1 configured as described above, the arm member 61 is not positioned at the tip of the subject table 15 with respect to the grating pitch direction (x direction) of the first absorption grating 31. Therefore, a relatively long subject H such as an arm or a leg can be arranged along the lattice pitch direction of the first absorption type lattice 31. Thus, for example, in the imaging of the knee joint shown in FIG. 18, the boundary between the joint fluid filling the joint space and the cartilage covering each of the femur B1 and the tibia B2 constituting the knee joint is the first absorption. Arranged so as to be substantially orthogonal to the lattice pitch direction (x direction) of the mold lattice 31, the edge of the cartilage is clearly depicted in the phase contrast image.
また、X線照射部11及び撮影部12並びに被写体台15は、片持ち梁状にアーム部材61に支持されるところ、上記の領域A2を通るようにアーム部材61を配置することにより、上記の領域A1を外れて鉛直方向に延在するアーム部材61をX線照射部11及び撮影部12並びに被写体台15に接近して配置することができる。それにより、梁長さを短縮し、X線照射部11及び撮影部12並びに被写体台15の傾きや振動を防止ないし抑制することができる。被写体Hを透過することで生じるX線の屈折は僅か数μradであり、この屈折によって生じるモアレ縞の変調、及び上述した縞走査法によってモアレ縞を解析して得られる信号の位相変化も僅かである。このような僅かな変化を計測する場合に、X線焦点18bや第1及び第2の吸収型格子31,32の相対位置のずれは、被写体Hの位相情報の検出精度に影響する。X線照射部11及び撮影部12並びに被写体台15の傾きや振動を防止ないし抑制することにより、X線焦点18bや第1及び第2の吸収型格子31,32の相対位置のずれを防止ないし抑制することができ、被写体Hの位相情報の検出精度を高めることができる。
Further, the X-ray irradiation unit 11, the imaging unit 12, and the subject table 15 are supported by the arm member 61 in a cantilever shape, and the arm member 61 is disposed so as to pass through the above-described region A2. The arm member 61 extending out of the area A1 and extending in the vertical direction can be disposed close to the X-ray irradiation unit 11, the imaging unit 12, and the subject table 15. Thereby, the beam length can be shortened, and the tilt and vibration of the X-ray irradiation unit 11, the imaging unit 12, and the subject table 15 can be prevented or suppressed. The refraction of the X-ray generated by passing through the subject H is only a few μrad, and the modulation of the moire fringe caused by this refraction and the phase change of the signal obtained by analyzing the moire fringe by the above-described fringe scanning method are also slight. is there. When such a slight change is measured, the relative position shift of the X-ray focal point 18b and the first and second absorption gratings 31 and 32 affects the detection accuracy of the phase information of the subject H. By preventing or suppressing the tilt or vibration of the X-ray irradiation unit 11, the imaging unit 12, and the subject table 15, the relative position of the X-ray focal point 18 b and the first and second absorption gratings 31 and 32 can be prevented from shifting. Therefore, the detection accuracy of the phase information of the subject H can be increased.
また、X線焦点18bや第1及び第2の吸収型格子31,32の相対位置のずれを防止ないし抑制する観点から、被写体台15は、衝撃や振動などを吸収ないし緩和する緩衝部材15a(図1参照)を介してアーム部材61に取り付けられている。それにより、被写体Hが被写体台15に載置された際の衝撃や、撮影中あるいは撮影間における被写体Hの動き(体動)による振動などがアーム部材61に伝達されることを防止ないし抑制することができる。それにより、上述の通り、X線焦点18bや第1及び第2の吸収型格子31,32の相対位置のずれを防止ないし抑制することができ、被写体Hの位相情報の検出精度を高めることができる。緩衝部材15aの材料としては、例えば硬質ゴムや各種樹脂等が適用できるが、緩衝部材15aの材料はこれらに限定されない。
Further, from the viewpoint of preventing or suppressing the displacement of the relative positions of the X-ray focal point 18b and the first and second absorption type gratings 31 and 32, the subject table 15 absorbs or relaxes shocks, vibrations, and the like. It is attached to the arm member 61 via FIG. Accordingly, it is possible to prevent or suppress an impact when the subject H is placed on the subject table 15, vibration due to a movement (body movement) of the subject H during or during photographing, and the like, from being transmitted to the arm member 61. be able to. Thereby, as described above, the relative position shift of the X-ray focal point 18b and the first and second absorption gratings 31 and 32 can be prevented or suppressed, and the detection accuracy of the phase information of the subject H can be improved. it can. As a material of the buffer member 15a, for example, hard rubber or various resins can be applied, but the material of the buffer member 15a is not limited thereto.
以上、X線撮影装置1によれば、第1の吸収型格子31の格子ピッチ方向に沿って被写体Hを配置する際に、アーム部材61が障害となることがなく、被写体Hを適切に配置して明瞭な位相コントラスト画像を得ることができる。
As described above, according to the X-ray imaging apparatus 1, when the subject H is arranged along the grating pitch direction of the first absorption type grating 31, the arm member 61 is not obstructed and the subject H is appropriately arranged. Thus, a clear phase contrast image can be obtained.
また、第1の吸収型格子31で殆どのX線を回折させずに、第2の吸収型格子32にほぼ幾何学的に投影するため、照射X線には、高い空間的可干渉性は要求されず、医療分野で用いられている一般的なX線源を用いることができる。そして、第1の吸収型格子31から第2の吸収型格子32までの距離L2を任意の値とすることができ、距離L2を、タルボ干渉計での最小のタルボ干渉距離より小さく設定することができるため、撮影部12を小型化(薄型化)することができる。
In addition, since most X-rays are not diffracted by the first absorption type grating 31 and are projected almost geometrically onto the second absorption type grating 32, the irradiated X-rays have high spatial coherence. It is not required and a general X-ray source used in the medical field can be used. The distance L 2 from the first absorption type grating 31 to the second absorption type grating 32 can be set to an arbitrary value, and the distance L 2 is set smaller than the minimum Talbot interference distance in the Talbot interferometer. Therefore, the photographing unit 12 can be downsized (thinned).
なお、第1の格子の投影像に対して第2の格子を重ね合わせてモアレ縞を生じさるものであって、そのため、第1及び第2の格子がいずれも吸収型格子であるものとして説明したが、本発明はこれに限定されるものではない。上述のとおり、タルボ干渉像に対して第2の格子を重ね合わせてモアレ縞を生じさせる場合にも、本発明は有用である。よって、第1の格子は、吸収型格子に限らず位相型格子であってもよい。第1の格子が0.5π位相型格子である場合に、タルボ干渉距離Zは、次式(23)で表され、タルボ干渉像のパターン周期p1’は、次式(24)で表される。また、第1の格子がπ位相型格子である場合に、タルボ干渉距離Zは、次式(25)で表され、タルボ干渉像のパターン周期p1’は、次式(26)で表される。
It is assumed that the second grating is superimposed on the projected image of the first grating to generate moire fringes, and therefore the first and second gratings are both absorption type gratings. However, the present invention is not limited to this. As described above, the present invention is also useful when the Moire fringes are generated by superimposing the second grating on the Talbot interference image. Therefore, the first grating is not limited to the absorption type grating but may be a phase type grating. When the first grating is a 0.5π phase grating, the Talbot interference distance Z is expressed by the following expression (23), and the pattern period p 1 ′ of the Talbot interference image is expressed by the following expression (24). The When the first grating is a π phase grating, the Talbot interference distance Z is expressed by the following expression (25), and the pattern period p 1 ′ of the Talbot interference image is expressed by the following expression (26). The
また、位相シフト分布Φを画像化したものを位相コントラスト画像として記憶ないし表示するものとして説明したが、位相シフト分布Φは、屈折角φより求まる位相シフト分布Φの微分量を積分したものであって、屈折角φ及び位相シフト分布Φの微分量もまた被写体によるX線の位相変化に関連している。よって、屈折角φを画像化したもの、また、位相シフトの微分量を画像化したものも位相コントラスト画像に含まれる。
In addition, although the image obtained by imaging the phase shift distribution Φ is described as being stored or displayed as a phase contrast image, the phase shift distribution Φ is obtained by integrating the differential amount of the phase shift distribution Φ obtained from the refraction angle φ. Thus, the differential amount of the refraction angle φ and the phase shift distribution Φ is also related to the X-ray phase change by the subject. Therefore, an image of the refraction angle φ and an image of the differential amount of the phase shift are also included in the phase contrast image.
また、被写体がない状態で撮影(プレ撮影)して取得されるモアレ縞に対して、上述の位相コントラスト画像の生成処理を行い、位相コントラスト画像を取得するようにしてもよい。この位相コントラスト画像は、例えば第1及び第2の吸収型格子31,32の不均一性等によって生じる位相ムラ(初期位相のズレ)を反映している。このプレ撮影における位相コントラスト画像を、被写体がある状態で撮影(メイン撮影)して取得される位相コントラスト画像から減算することで、撮影部12の位相ムラを補正した位相コントラスト画像を得ることが出来る。
Further, the above-described phase contrast image generation processing may be performed on the moire fringes obtained by photographing (pre-photographing) in the absence of a subject, and the phase contrast image may be obtained. This phase contrast image reflects, for example, phase unevenness (initial phase shift) caused by non-uniformity of the first and second absorption gratings 31 and 32. By subtracting the phase contrast image in the pre-photographing from the phase contrast image obtained by photographing (main photographing) in the presence of the subject, a phase contrast image in which the phase unevenness of the photographing unit 12 is corrected can be obtained. .
図19は、X線撮影装置1の変形例の構成を示す。
FIG. 19 shows a configuration of a modified example of the X-ray imaging apparatus 1.
図19に示すX線撮影装置は、X線照射部11にマルチスリット35が配設されている点で、図1に示すX線撮影装置1と異なる。
19 differs from the X-ray imaging apparatus 1 shown in FIG. 1 in that the multi-slit 35 is disposed in the X-ray irradiation unit 11.
上述したX線撮影装置1において、X線照射部11からX線画像検出器30までの距離を、一般的な病院の撮影室で設定されるような距離(1m~2m)とした場合に、X線焦点18bの焦点サイズ(一般的に0.1mm~1mm程度)によるG1像のボケが影響し、位相コントラスト画像の画質の低下をもたらす恐れがある。そこで、X線焦点18bの直後にピンホールを設置して実効的に焦点サイズを小さくすることが考えられるが、実効的な焦点サイズを縮小するためにピンホールの開口面積を小さくすると、X線強度が低下してしまう。本例においては、この課題を解決するために、X線焦点18bの直後にマルチスリット35を配置する。
In the X-ray imaging apparatus 1 described above, when the distance from the X-ray irradiation unit 11 to the X-ray image detector 30 is set to a distance (1 m to 2 m) as set in a general hospital imaging room, The blur of the G1 image due to the focal size of the X-ray focal point 18b (generally about 0.1 mm to 1 mm) is affected, and there is a possibility that the image quality of the phase contrast image is degraded. Therefore, it is conceivable to install a pinhole immediately after the X-ray focal point 18b to effectively reduce the focal spot size. However, if the aperture area of the pinhole is reduced to reduce the effective focal spot size, the X-ray focal point is reduced. Strength will fall. In this example, in order to solve this problem, the multi slit 35 is disposed immediately after the X-ray focal point 18b.
マルチスリット35は、第1及び第2の吸収型格子31,32と同様な構成の吸収型格子(第3の吸収型格子)であり、一方向に延伸した複数のX線遮蔽部が、第1及び第2の吸収型格子31,32のX線遮蔽部31b,32bと同一方向(x方向)に周期的に配列されている。このマルチスリット35は、X線焦点18bから放射される放射線を部分的に遮蔽することにより、x方向に所定のピッチで配列された小焦点光源(分散光源)を形成することを目的としている。
The multi slit 35 is an absorption type grating (third absorption type grating) having the same configuration as that of the first and second absorption type gratings 31 and 32, and a plurality of X-ray shielding portions extending in one direction are provided in the first slit. The first and second absorption type gratings 31 and 32 are periodically arranged in the same direction (x direction) as the X-ray shielding portions 31b and 32b. The purpose of the multi-slit 35 is to form small focal light sources (dispersed light sources) arranged at a predetermined pitch in the x direction by partially shielding the radiation emitted from the X-ray focal point 18b.
このマルチスリット35の格子ピッチp3は、マルチスリット35から第1の吸収型格子31までの距離をL3として、次式(27)を満たすように設定する必要がある。
The lattice pitch p 3 of the multi-slit 35 needs to be set so as to satisfy the following equation (27), where L 3 is the distance from the multi-slit 35 to the first absorption-type lattice 31.
式(27)は、マルチスリット35により分散形成された各小焦点光源から射出されたX線の第1の吸収型格子31による投影像(G1像)が、第2の吸収型格子32の位置で一致する(重なり合う)ための幾何学的な条件である。
Expression (27) indicates that the projection image (G1 image) of the X-rays emitted from the small focus light sources dispersedly formed by the multi-slit 35 by the first absorption type grating 31 is the position of the second absorption type grating 32. This is a geometric condition for matching (overlapping).
また、実質的にマルチスリット35の位置がX線焦点位置となるため、第2の吸収型格子32の格子ピッチp2は、次式(28)の関係を満たすように決定される。
In addition, since the position of the multi-slit 35 is substantially the X-ray focal position, the grating pitch p2 of the second absorption grating 32 is determined so as to satisfy the relationship of the following equation (28).
このように、本例においては、マルチスリット35により形成される複数の点光源に基づくG1像が重ね合わせられることにより、X線強度を低下させずに、位相コントラスト画像の画質を向上させることができる。
As described above, in this example, the G1 images based on the plurality of point light sources formed by the multi-slit 35 are superimposed, so that the image quality of the phase contrast image can be improved without reducing the X-ray intensity. it can.
なお、本例において、X線画像検出器30によって取得される画像の周期パターンの解析方法としては、上述した解析方法1~3のいずれも適用可能であるが、第1の吸収型格子31の光軸Cを中心とする回転を伴う場合に、マルチスリット35もまた、その格子ピッチ方向が第1の吸収型格子31の格子ピッチ方向に一致するように、第1の吸収型格子31とともに回転されることが好ましい。また、上述した解析方法1において、G1像と第2の吸収型格子32の相対的位置関係を変えるときに、マルチスリット35をそのX線遮蔽部と交差する方向に動かすことでも実施可能である。
In this example, as a method for analyzing the periodic pattern of the image acquired by the X-ray image detector 30, any of the above-described analysis methods 1 to 3 can be applied. When accompanied by rotation about the optical axis C, the multi-slit 35 also rotates together with the first absorption grating 31 so that the grating pitch direction coincides with the grating pitch direction of the first absorption grating 31. It is preferred that Further, in the analysis method 1 described above, when changing the relative positional relationship between the G1 image and the second absorption grating 32, the multi-slit 35 can be moved in a direction intersecting the X-ray shielding portion. .
図20は、本発明の実施形態を説明するための放射線撮影装置の他の例の構成を示す。なお、図1に示すX線撮影装置1と共通する要素には、共通の符号を付することにより説明を省略あるいは簡略する。
FIG. 20 shows the configuration of another example of a radiation imaging apparatus for explaining an embodiment of the present invention. Elements common to the X-ray imaging apparatus 1 shown in FIG. 1 are denoted by common reference numerals, and description thereof is omitted or simplified.
図20に示すX線撮影装置101は、第1の吸収型格子31がX線照射部11と被写体台15との間に配置されている点で、図1に示すX線撮影装置1と異なっている。
An X-ray imaging apparatus 101 shown in FIG. 20 is different from the X-ray imaging apparatus 1 shown in FIG. 1 in that the first absorption type grating 31 is disposed between the X-ray irradiation unit 11 and the subject table 15. ing.
第1の吸収型格子31は、保持部材34に保持されており、保持部材34を介してアーム部材61に取り付けられている。保持部材34は、片持ち梁状にアーム部材61に支持されることになるため、剛性が高い程好ましく、例えば、第1の吸収型格子31の基板31aよりも剛性の高い部材を用いることが好ましい。それにより、X線焦点18bや第1及び第2の吸収型格子31,32の相対位置のずれを防止ないし抑制することができ、被写体Hの位相情報の検出精度を高めることができる。
The first absorption type lattice 31 is held by the holding member 34 and is attached to the arm member 61 via the holding member 34. Since the holding member 34 is supported by the arm member 61 in a cantilever shape, it is preferable that the holding member 34 has high rigidity. For example, a member having higher rigidity than the substrate 31a of the first absorption type lattice 31 is used. preferable. Thereby, the relative position shift of the X-ray focal point 18b and the first and second absorption gratings 31 and 32 can be prevented or suppressed, and the detection accuracy of the phase information of the subject H can be improved.
以上の構成において、被写体Hは第1の吸収型格子31と第2の吸収型格子32との間に配置されることになるが、第2の吸収型格子32の位置に形成される第1の吸収型格子31のG1像は被写体Hにより変調を受ける。そして、図1に示すX線撮影装置1と同様に、第2の吸収型格子32との重ね合わせにより、G1像は強度変調され、強度変調されたG1像がX線画像検出器30によって撮像される。従って、本X線撮影装置101においても、図1に示すX線撮影装置1において説明した解析方法1~3と同様の原理で被写体Hの位相コントラスト画像を得ることができる。
In the configuration described above, the subject H is disposed between the first absorption type grating 31 and the second absorption type grating 32, but the first object formed at the position of the second absorption type grating 32. The G1 image of the absorption type grating 31 is modulated by the subject H. As in the X-ray imaging apparatus 1 shown in FIG. 1, the G1 image is intensity-modulated by superposition with the second absorption grating 32, and the intensity-modulated G1 image is captured by the X-ray image detector 30. Is done. Therefore, the X-ray imaging apparatus 101 can also obtain a phase contrast image of the subject H on the same principle as the analysis methods 1 to 3 described in the X-ray imaging apparatus 1 shown in FIG.
そして、本X線撮影装置101では、第1の吸収型格子31による遮蔽により、線量がほぼ半減したX線が被写体Hに照射されることになるため、被写体Hの被曝量を、図1に示すX線撮影装置1の場合の約半分に低減することができる。
In this X-ray imaging apparatus 101, the subject H is irradiated with X-rays whose dose is almost halved by shielding with the first absorption type grating 31. Therefore, the exposure amount of the subject H is shown in FIG. It can be reduced to about half that of the X-ray imaging apparatus 1 shown.
なお、本X線撮影装置101において、第1の格子は、吸収型格子に限られず位相型格子であってもよい。
In the X-ray imaging apparatus 101, the first grating is not limited to the absorption grating but may be a phase grating.
また、本X線撮影装置101において、上述したマルチスリット35(図19参照)を設けることができる。
Further, in the X-ray imaging apparatus 101, the above-described multi slit 35 (see FIG. 19) can be provided.
図21は、本発明の実施形態を説明するための放射線撮影装置の他の例の構成を示す。なお、図1に示すX線撮影装置1と共通する要素には、共通の符号を付することにより説明を省略あるいは簡略する。
FIG. 21 shows the configuration of another example of a radiation imaging apparatus for explaining the embodiment of the present invention. Elements common to the X-ray imaging apparatus 1 shown in FIG. 1 are denoted by common reference numerals, and description thereof is omitted or simplified.
図21に示すX線撮影装置201は、撮影部212が第1の吸収型格子31及びX線画像検出器230によって大略構成されており、第2の吸収型格子32が省かれている点で、図1に示すX線撮影装置1と異なっている。
In the X-ray imaging apparatus 201 shown in FIG. 21, the imaging unit 212 is roughly constituted by the first absorption type grating 31 and the X-ray image detector 230, and the second absorption type grating 32 is omitted. 1 is different from the X-ray imaging apparatus 1 shown in FIG.
X線画像検出器230は、X線を電荷に変換して蓄積する複数の画素40が2次元配列されてなる受像部41を備え、各画素40に蓄積された電荷を読み出し、これを画像データに変換してコンソール3に送信する。
The X-ray image detector 230 includes an image receiving unit 41 in which a plurality of pixels 40 that convert X-rays into electric charges and store them are two-dimensionally arranged, read out the electric charges accumulated in each pixel 40, and read them out as image data. To be sent to the console 3.
複数の画素40は、X線画像検出器230の受像面上に形成されるG1像の周期的強度分布を解像可能な配列ピッチで配列されている。具体的には、画素40の配列ピッチPは、一般に数μmであるG1像の周期的強度分布のパターン周期p1’の1/2以下、好ましくは1/5以下のピッチとされる。そのような微小な配列ピッチに複数の画素が配列されるX線画像検出器は、各画素に蓄積された電荷を読み出す読み出し回路が単結晶シリコン等からなる半導体基板に形成される、CCDセンサやCMOSセンサなどの固体撮像素子をベースに構成することができる。なお、上記の画素の配列ピッチPを満たす限りにおいて、TFTパネルをベースに構成されたものを用いることもできる。
The plurality of pixels 40 are arranged at an arrangement pitch capable of resolving the periodic intensity distribution of the G1 image formed on the image receiving surface of the X-ray image detector 230. Specifically, the arrangement pitch P of the pixels 40 is set to a pitch of 1/2 or less, preferably 1/5 or less of the pattern period p 1 ′ of the periodic intensity distribution of the G1 image, which is generally several μm. An X-ray image detector in which a plurality of pixels are arranged in such a small arrangement pitch is a CCD sensor or a read circuit that is formed on a semiconductor substrate made of single crystal silicon or the like, and a readout circuit that reads out the electric charge accumulated in each pixel. A solid-state imaging device such as a CMOS sensor can be used as a base. In addition, as long as the pixel arrangement pitch P is satisfied, the one configured based on the TFT panel may be used.
以上の構成において、G1像がX線画像検出器230上に形成される。そして、X線照射部11と撮影部212との間、より詳細にはX線照射部11と第1の吸収型格子31との間に配置された被写体台15に被写体Hを配置した場合に、G1像の周期的強度分布は、被写体Hにより変調を受ける。G1像をX線画像検出器230によって撮像して取得される画像には、G1像の周期的強度分布に対応する周期パターンが含まれ、この周期パターンを解析することによって、被写体Hの位相コントラスト画像を生成することができる。
In the above configuration, the G1 image is formed on the X-ray image detector 230. When the subject H is arranged on the subject table 15 arranged between the X-ray irradiation unit 11 and the imaging unit 212, more specifically between the X-ray irradiation unit 11 and the first absorption type grating 31. The periodic intensity distribution of the G1 image is modulated by the subject H. The image acquired by capturing the G1 image by the X-ray image detector 230 includes a periodic pattern corresponding to the periodic intensity distribution of the G1 image. By analyzing this periodic pattern, the phase contrast of the subject H is analyzed. An image can be generated.
以下、X線撮影装置201における画像の周期パターンの解析方法について説明する。
Hereinafter, a method for analyzing a periodic pattern of an image in the X-ray imaging apparatus 201 will be described.
〔解析方法1〕
画像の周期パターンの解析は、例えば上述した縞走査法によって行うことができる。まず、第1の吸収型格子31からX線画像検出器230の位置に投射されたG1像は、被写体HでのX線の屈折により、その屈折角φに応じた量だけx方向に変位することになる。この変位量Δxは、X線の屈折角φが微小であることに基づいて、近似的に次式(29)で表される。なお、L4は、第1の吸収型格子31からX線画像検出器230までの距離を示す。 [Analysis method 1]
The analysis of the periodic pattern of the image can be performed, for example, by the above-described fringe scanning method. First, the G1 image projected from the first absorption type grating 31 to the position of theX-ray image detector 230 is displaced in the x direction by an amount corresponding to the refraction angle φ due to refraction of X-rays at the subject H. It will be. This displacement amount Δx is approximately expressed by the following equation (29) based on the fact that the X-ray refraction angle φ is very small. L 4 indicates the distance from the first absorption type grating 31 to the X-ray image detector 230.
画像の周期パターンの解析は、例えば上述した縞走査法によって行うことができる。まず、第1の吸収型格子31からX線画像検出器230の位置に投射されたG1像は、被写体HでのX線の屈折により、その屈折角φに応じた量だけx方向に変位することになる。この変位量Δxは、X線の屈折角φが微小であることに基づいて、近似的に次式(29)で表される。なお、L4は、第1の吸収型格子31からX線画像検出器230までの距離を示す。 [Analysis method 1]
The analysis of the periodic pattern of the image can be performed, for example, by the above-described fringe scanning method. First, the G1 image projected from the first absorption type grating 31 to the position of the
ここで、屈折角φは、X線波長λと被写体Hの位相シフト分布Φ(x)を用いて、式(30)で表される。
Here, the refraction angle φ is expressed by Expression (30) using the X-ray wavelength λ and the phase shift distribution Φ (x) of the subject H.
このように、被写体HでのX線の屈折によるG1像の変位量Δxは、被写体Hの位相シフト分布Φ(x)に関連している。そして、この変位量Δxは、画像データの各画素の信号の位相ズレ量ψに、次式(31)のように関連している。
Thus, the displacement amount Δx of the G1 image due to the refraction of X-rays at the subject H is related to the phase shift distribution Φ (x) of the subject H. The displacement amount Δx is related to the phase shift amount ψ of the signal of each pixel of the image data as in the following equation (31).
したがって、各画素の信号の位相ズレ量ψを求めることにより、式(31)から屈折角φが求まり、式(30)を用いて位相シフト分布Φ(x)の微分量が求まるから、これをxについて積分することにより、被写体Hの位相シフト分布Φ(x)、すなわち被写体Hの位相コントラスト画像を生成することができる。上記の位相ズレ量ψを、縞走査法を用いて算出する。
Therefore, by obtaining the phase shift amount ψ of the signal of each pixel, the refraction angle φ is obtained from the equation (31), and the differential amount of the phase shift distribution Φ (x) is obtained using the equation (30). By integrating with respect to x, the phase shift distribution Φ (x) of the subject H, that is, the phase contrast image of the subject H can be generated. The phase shift amount ψ is calculated using a fringe scanning method.
すなわち、第1の吸収型格子31を、その格子の格子ピッチ方向(x方向)にX線画像検出器230に対してステップ的に並進移動させ、G1像の周期的強度分布に対する画素40の周期的配列の位相を相対的に変化させながら撮影を行う。第1の吸収型格子31の移動は、走査機構33により行うことができる。
That is, the first absorption type grating 31 is translated in a stepwise manner relative to the X-ray image detector 230 in the grating pitch direction (x direction) of the grating, and the period of the pixel 40 with respect to the periodic intensity distribution of the G1 image. Shooting while relatively changing the phase of the target array. The movement of the first absorption type grating 31 can be performed by the scanning mechanism 33.
第1の吸収型格子31の移動に伴って、G1像が移動し、並進距離(x方向への移動量)が、第1の吸収型格子31の格子周期の1周期(格子ピッチp1)に達すると(すなわち、位相変化が2πに達すると)、G1像は元の位置に戻る。このようなG1像の変化を、格子ピッチp1の整数分の1の距離ずつ第1の吸収型格子31を移動させながら、X線画像検出器230で撮像し、得られた複数の画像データから画素毎に複数個の信号値を取得し、演算処理部22で演算処理することによって各画素の信号の位相ズレ量ψを得る。そして、各画素の信号の位相ズレ量ψから式(31)を用いて屈折角φが求まり、式(30)を用いて位相シフト分布Φ(x)の微分量が求まるから、これをxについて積分することにより、被写体Hの位相シフト分布Φ(x)、すなわち被写体Hの位相コントラスト画像を生成する。
As the first absorption type grating 31 moves, the G1 image moves, and the translation distance (the amount of movement in the x direction) is one period of the grating period of the first absorption type grating 31 (grating pitch p 1 ). (Ie, when the phase change reaches 2π), the G1 image returns to its original position. Such a change in the G1 image is picked up by the X-ray image detector 230 while moving the first absorption type grating 31 by a distance of 1 / integer of the grating pitch p 1 , and a plurality of obtained image data A plurality of signal values are obtained from each pixel, and the arithmetic processing unit 22 performs arithmetic processing to obtain a phase shift amount ψ of the signal of each pixel. Then, the refraction angle φ is obtained from the phase shift amount ψ of the signal of each pixel using the equation (31), and the differential amount of the phase shift distribution Φ (x) is obtained using the equation (30). By integrating, the phase shift distribution Φ (x) of the subject H, ie, the phase contrast image of the subject H is generated.
〔解析方法2〕
図22は、X線撮影装置201における位相コントラスト画像の生成方法の他の例を示す。 [Analysis method 2]
FIG. 22 shows another example of a method for generating a phase contrast image in theX-ray imaging apparatus 201.
図22は、X線撮影装置201における位相コントラスト画像の生成方法の他の例を示す。 [Analysis method 2]
FIG. 22 shows another example of a method for generating a phase contrast image in the
第1の吸収型格子31の格子ピッチ方向(x方向)に並ぶ複数の画素を一単位とし、単位毎に、その単位を構成する複数の画素の信号値Iを補間する。図示の例では、複数の画素の信号値を正弦曲線により補間したものであり、正弦曲線による補間は少なくとも3点あれば足りるため、互いに隣り合う3つの画素を単位としている。
A plurality of pixels arranged in the lattice pitch direction (x direction) of the first absorption type lattice 31 is defined as one unit, and the signal values I of the plurality of pixels constituting the unit are interpolated for each unit. In the example shown in the figure, signal values of a plurality of pixels are interpolated by a sine curve, and at least three points are sufficient for interpolation by the sine curve, and therefore three adjacent pixels are used as a unit.
上述した通り、G1像は、被写体HでのX線の屈折により、その屈折角φに応じた量だけx方向に変位することになる。G1像の変位に伴い、単位毎に、その単位を構成する複数の画素の信号値Iを補間してなる信号波形の位相が変化する。被写体Hが存在しない場合の信号波形(FIG.22A)と、被写体Hが存在する場合の信号波形(FIG.22B)との両者の波形の位相差が、その単位に含まれる画素の信号の位相ズレ量ψに対応する。各画素の信号の位相ズレ量ψから式(31)を用いて屈折角φが求まり、式(30)を用いて位相シフト分布Φ(x)の微分量が求まるから、これをxについて積分することにより、被写体Hの位相シフト分布Φ(x)、すなわち被写体Hの位相コントラスト画像を生成する。
As described above, the G1 image is displaced in the x direction by an amount corresponding to the refraction angle φ due to refraction of X-rays at the subject H. Along with the displacement of the G1 image, the phase of the signal waveform formed by interpolating the signal values I of a plurality of pixels constituting the unit changes for each unit. The phase difference between the waveform of the signal waveform (FIG. 22A) when the subject H is not present and the signal waveform (FIG. 22B) when the subject H is present is the phase of the signal of the pixel included in the unit. This corresponds to the displacement amount ψ. The refraction angle φ is obtained from the phase shift amount ψ of the signal of each pixel using the equation (31) and the differential amount of the phase shift distribution Φ (x) is obtained using the equation (30), and this is integrated with respect to x. Thus, the phase shift distribution Φ (x) of the subject H, that is, the phase contrast image of the subject H is generated.
なお、第1の吸収型格子31の格子ピッチ方向(x方向)とX線画像検出器230における画素40の配列における行方向又は列方向とが一致しているものとして、第1の吸収型格子31の格子ピッチ方向、つまりはG1像の周期的強度分布のパターン周期方向に並ぶ3つの画素を一単位とするものとして説明したが、G1像の周期的強度分布のパターンに対して交差する方向に並ぶ3画素以上の複数の画素を一単位としてG1像の周期的強度分布を解像すれば、単位毎に、その単位に含まれる画素の信号の位相ズレ量ψを算出することができる。従って、G1像の周期的強度分布のパターン周期方向に対して、画素40の配列における行方向及び列方向がいずれも交差するように、第1の吸収型格子31とX線画像検出器230とが、光軸Cを中心として相対的に回転して配置されていてもよい。
Note that the first absorption-type grating is assumed that the grating pitch direction (x-direction) of the first absorption-type grating 31 coincides with the row direction or the column direction in the arrangement of the pixels 40 in the X-ray image detector 230. Although the description has been made assuming that three pixels arranged in the lattice pitch direction of 31, that is, the pattern periodic direction of the periodic intensity distribution of the G1 image, are taken as one unit, the direction intersecting the periodic intensity distribution pattern of the G1 image If the periodic intensity distribution of the G1 image is resolved with a plurality of pixels of three or more arranged in a unit as a unit, the phase shift amount ψ of the signal of the pixel included in the unit can be calculated for each unit. Therefore, the first absorption grating 31 and the X-ray image detector 230 are arranged such that the row direction and the column direction in the arrangement of the pixels 40 intersect with the pattern period direction of the periodic intensity distribution of the G1 image. However, the optical axis C may be relatively rotated around the optical axis C.
〔解析方法3〕
本X線撮影装置201においても、図1に示すX線撮影装置1と同様に、フーリエ変換及び逆フーリエ変換を用いて画像の周期パターンを解析し、位相コントラスト画像を生成することができる。なお、この場合に、画像の周期パターンは、図1に示すX線撮影装置1においては、G1像と第2の吸収型格子32との重ね合わせによって形成されるモアレ縞に対応するが、本X線撮影装置201においては、G1像の周期的強度分布に対応する。 [Analysis method 3]
Similarly to theX-ray imaging apparatus 1 shown in FIG. 1, the X-ray imaging apparatus 201 can also generate a phase contrast image by analyzing a periodic pattern of an image using Fourier transform and inverse Fourier transform. In this case, in the X-ray imaging apparatus 1 shown in FIG. 1, the periodic pattern of the image corresponds to moire fringes formed by superimposing the G1 image and the second absorption type grating 32. In the X-ray imaging apparatus 201, this corresponds to the periodic intensity distribution of the G1 image.
本X線撮影装置201においても、図1に示すX線撮影装置1と同様に、フーリエ変換及び逆フーリエ変換を用いて画像の周期パターンを解析し、位相コントラスト画像を生成することができる。なお、この場合に、画像の周期パターンは、図1に示すX線撮影装置1においては、G1像と第2の吸収型格子32との重ね合わせによって形成されるモアレ縞に対応するが、本X線撮影装置201においては、G1像の周期的強度分布に対応する。 [Analysis method 3]
Similarly to the
以上、本X線撮影装置201によれば、G1像の周期的強度分布の周期よりも小さい画素ピッチの検出器を用いてG1像の周期的強度分布を検出し、これを解析して位相情報を取得しており、画素ピッチが小さいことから空間分解能に優れる。そして、第2の吸収型格子32を介さないことから位相情報の検出精度の向上が図られる。
As described above, according to the X-ray imaging apparatus 201, the periodic intensity distribution of the G1 image is detected using a detector having a pixel pitch smaller than the period of the periodic intensity distribution of the G1 image, and this is analyzed to obtain phase information. Since the pixel pitch is small, the spatial resolution is excellent. Further, since the second absorption type grating 32 is not interposed, the detection accuracy of the phase information can be improved.
なお、本X線撮影装置201において、第1の格子は吸収型格子に限られず位相型格子であってもよい。
In the X-ray imaging apparatus 201, the first grating is not limited to the absorption grating but may be a phase grating.
また、本X線撮影装置201において、そのX線照射部11に、上述したマルチスリット35(図19参照)を設けることができる。この場合に、マルチスリットの格子ピッチp3は、マルチスリットから第1の吸収型格子31までの距離をL3として、次式(32)を満たすように設定される。
In the X-ray imaging apparatus 201, the X-ray irradiation unit 11 can be provided with the multi slit 35 (see FIG. 19) described above. In this case, the multi-slit lattice pitch p 3 is set to satisfy the following equation (32), where L 3 is the distance from the multi-slit to the first absorption type lattice 31.
式(32)は、マルチスリットにより分散形成された各小焦点光源から射出されたX線の第1の吸収型格子31による投影像(G1像)が、X線画像検出器230の位置で一致する(重なり合う)ための幾何学的な条件である。
Expression (32) indicates that the projection image (G1 image) of the X-rays emitted from the small-focus light sources dispersedly formed by the multi-slits by the first absorption type grating 31 coincides with the position of the X-ray image detector 230. It is a geometrical condition for doing (overlapping).
また、本X線撮影装置201において、第1の吸収型格子31を、X線照射部11と被写体台15との間に配置することもできる。
In the X-ray imaging apparatus 201, the first absorption type grating 31 can also be disposed between the X-ray irradiation unit 11 and the subject table 15.
図23は、図21のX線撮影装置の変形例を示す。
FIG. 23 shows a modification of the X-ray imaging apparatus of FIG.
図23に示すX線撮影装置201Aにおいて、X線画像検出器230Aの複数の画素40は、X線画像検出器230Aの受像面上に形成されるG1像の周期的強度分布のパターン周期との関係においてモアレを生じる配列ピッチで配列されている。具体的には、画素40の配列ピッチPは、一般に数μmであるG1像の周期的強度分布のパターン周期と略同程度の配列ピッチとされる。
In the X-ray imaging apparatus 201A shown in FIG. 23, the plurality of pixels 40 of the X-ray image detector 230A have a pattern period of the periodic intensity distribution of the G1 image formed on the image receiving surface of the X-ray image detector 230A. They are arranged at an arrangement pitch that causes moire in the relationship. Specifically, the arrangement pitch P of the pixels 40 is set to be approximately the same as the pattern period of the periodic intensity distribution of the G1 image, which is generally several μm.
以上の構成において、G1像の周期的強度分布のx方向に関するパターン周期p1’と画素40のx方向に関する配列ピッチPに微小な差異(設計上の差異に限らず、製造誤差や配置誤差に起因する差異も含む)があると、X線画像検出器230Aによって取得される画像にはモアレが生じる。本X線撮影装置201Aにおいては、このモアレを解析することによって、被写体Hの位相コントラスト画像を生成する。
In the above configuration, there is a slight difference between the pattern period p 1 ′ in the x direction of the periodic intensity distribution of the G1 image and the arrangement pitch P in the x direction of the pixels 40 (not limited to design differences, but manufacturing errors and arrangement errors). If there is a difference due to this, moire occurs in the image acquired by the X-ray image detector 230A. The X-ray imaging apparatus 201A generates a phase contrast image of the subject H by analyzing the moire.
画素40の配列ピッチPは、設計的に定められた値であり変更することが困難であるため、モアレを生じさせるにあたって、画素40の配列ピッチPとG1像の周期的強度分布のパターン周期p1’との関係を調整するには、第1の吸収型格子31の位置調整を行い、G1像のパターン周期p1’を変更することにより調整することが好ましい。G1像の周期的強度分布のパターン周期を変更するための機構には、上述した相対回転機構50や相対傾斜機構51や相対移動機構52(いずれも図6参照)と同様の機構を用いることができる。
Since the arrangement pitch P of the pixels 40 is a value determined in terms of design and is difficult to change, when generating moire, the arrangement pitch P of the pixels 40 and the pattern period p of the periodic intensity distribution of the G1 image. In order to adjust the relationship with 1 ′, it is preferable to adjust the position of the first absorption grating 31 by changing the pattern period p 1 ′ of the G1 image. As a mechanism for changing the pattern period of the periodic intensity distribution of the G1 image, a mechanism similar to the above-described relative rotation mechanism 50, relative tilt mechanism 51, and relative movement mechanism 52 (all refer to FIG. 6) is used. it can.
画素40の配列ピッチPと、G1像の周期的強度分布のパターン周期p1’との関係において、画像に生じるモアレのx方向に関する周期Tは、次式(33)で表される。
In the relationship between the array pitch P of the pixels 40 and the pattern period p 1 ′ of the periodic intensity distribution of the G1 image, the period T in the x direction of moire generated in the image is expressed by the following equation (33).
X線照射部11と吸収型格子31との間に被写体Hを配置すると、X線画像検出器230Aにより取得される画像に生じるモアレは、被写体Hにより変調を受ける。この変調量は、被写体Hによる屈折効果によって偏向したX線の角度に比例する。したがって、このモアレを解析することによって、被写体Hの位相コントラスト画像を生成することができる。
When the subject H is arranged between the X-ray irradiation unit 11 and the absorption type grating 31, moire generated in an image acquired by the X-ray image detector 230A is modulated by the subject H. This modulation amount is proportional to the angle of the X-ray deflected by the refraction effect by the subject H. Therefore, a phase contrast image of the subject H can be generated by analyzing this moire.
以下、X線撮影装置201Aにおける画像のモアレの解析方法について説明する。
Hereinafter, a method of analyzing image moire in the X-ray imaging apparatus 201A will be described.
〔解析方法1〕
画像の周期パターンの解析は、例えば上述した縞走査法によって行うことができる。まず、第1の吸収型格子31からX線画像検出器230Aの位置に投射されたG1像は、被写体HでのX線の屈折により、その屈折角φに応じた量だけx方向に変位することになる。この変位量Δxは、上記の式(29)及び式(30)から明らかなように、被写体Hの位相シフト分布Φ(x)に関連している。 [Analysis method 1]
The analysis of the periodic pattern of the image can be performed, for example, by the above-described fringe scanning method. First, the G1 image projected from the first absorption type grating 31 to the position of theX-ray image detector 230A is displaced in the x direction by an amount corresponding to the refraction angle φ due to refraction of X-rays at the subject H. It will be. This displacement amount Δx is related to the phase shift distribution Φ (x) of the subject H, as is apparent from the above equations (29) and (30).
画像の周期パターンの解析は、例えば上述した縞走査法によって行うことができる。まず、第1の吸収型格子31からX線画像検出器230Aの位置に投射されたG1像は、被写体HでのX線の屈折により、その屈折角φに応じた量だけx方向に変位することになる。この変位量Δxは、上記の式(29)及び式(30)から明らかなように、被写体Hの位相シフト分布Φ(x)に関連している。 [Analysis method 1]
The analysis of the periodic pattern of the image can be performed, for example, by the above-described fringe scanning method. First, the G1 image projected from the first absorption type grating 31 to the position of the
そして、G1像のx方向の変位に伴ってモアレもまたx方向に変位し、G1像の変位量Δxが周期p1’に達するとモアレは元の状態にもどることから、モアレの変位量ΔXは、モアレのx方向に関する周期をTとして、G1像の変位量Δxを用いて、次式(34)で表される。
As the G1 image is displaced in the x direction, the moire is also displaced in the x direction. When the displacement amount Δx of the G1 image reaches the period p 1 ′, the moire returns to the original state. Is expressed by the following equation (34) using the displacement amount Δx of the G1 image, where T is the period of the moire in the x direction.
この変位量ΔXは、画像データの各画素の信号の位相ズレ量ψに、次式(35)のように関連している。
This displacement amount ΔX is related to the phase shift amount ψ of the signal of each pixel of the image data as shown in the following equation (35).
したがって、各画素の信号の位相ズレ量ψを求めることにより、式(31)から屈折角φが求まり、式(30)を用いて位相シフト分布Φ(x)の微分量が求まるから、これをxについて積分することにより、被写体Hの位相シフト分布Φ(x)、すなわち被写体Hの位相コントラスト画像を生成することができる。上記の位相ズレ量ψを、縞走査法を用いて算出する。
Accordingly, by obtaining the phase shift amount ψ of the signal of each pixel, the refraction angle φ is obtained from the equation (31), and the differential amount of the phase shift distribution Φ (x) is obtained using the equation (30). By integrating with respect to x, the phase shift distribution Φ (x) of the subject H, that is, the phase contrast image of the subject H can be generated. The phase shift amount ψ is calculated using a fringe scanning method.
すなわち、第1の吸収型格子31を、その格子の格子ピッチ方向(x方向)にX線画像検出器230Aに対してステップ的に並進移動させ、G1像の周期的強度分布に対する画素40の周期的配列の位相を相対的に変化させながら撮影を行う。第1の吸収型格子31の移動は走査機構33により行うことができる。
That is, the first absorption type grating 31 is translated stepwise in the grating pitch direction (x direction) of the grating with respect to the X-ray image detector 230A, and the period of the pixel 40 with respect to the periodic intensity distribution of the G1 image. Shooting while relatively changing the phase of the target array. The movement of the first absorption type grating 31 can be performed by the scanning mechanism 33.
第1の吸収型格子31の移動に伴ってモアレもまた移動し、並進距離(x方向への移動量)が第1の吸収型格子31の格子周期の1周期(格子ピッチp1)に達すると(すなわち、位相変化が2πに達すると)、モアレは元の状態に戻る。このようなモアレの変化を伴う吸収型格子31の移動を格子ピッチp1の整数分の1の走査ピッチで行いながら撮影し、得られた複数の画像データから画素毎に複数個の信号値を取得し、演算処理部22で演算処理することによって各画素の信号の位相ズレ量ψを得る。そして、各画素の信号の位相ズレ量ψから式(31)を用いて屈折角φが求まり、式(30)を用いて位相シフト分布Φ(x)の微分量が求まるから、これをxについて積分することにより、被写体Hの位相シフト分布Φ(x)、すなわち被写体Hの位相コントラスト画像を生成する。
As the first absorption type grating 31 moves, the moire also moves, and the translation distance (amount of movement in the x direction) reaches one period (grating pitch p 1 ) of the grating period of the first absorption type grating 31. Then (ie, when the phase change reaches 2π), the moire returns to the original state. Such movement of the absorption-type grating 31 with a change in the moiré taken while one scan pitch of an integral fraction of the grating pitch p 1, a plurality of signal values from a plurality of image data for each pixel obtained The phase shift amount ψ of the signal of each pixel is obtained by obtaining and performing arithmetic processing in the arithmetic processing unit 22. Then, the refraction angle φ is obtained from the phase shift amount ψ of the signal of each pixel using the equation (31), and the differential amount of the phase shift distribution Φ (x) is obtained using the equation (30). By integrating, the phase shift distribution Φ (x) of the subject H, ie, the phase contrast image of the subject H is generated.
なお、上述した縞走査法によるモアレの解析においては、第1の吸収型格子31とX線画像検出器230Aとの相対移動に伴ってモアレが全体として移動するため、モアレの周期が画像サイズに比べて長くとも適用可能である。
In the moire analysis by the above-described fringe scanning method, the moire moves as a whole with the relative movement between the first absorption grating 31 and the X-ray image detector 230A. It is applicable even if it is longer than that.
〔解析方法2〕
図24は、X線撮影装置201Aにおける位相コントラスト画像の生成方法の他の例を示す。 [Analysis method 2]
FIG. 24 shows another example of a method for generating a phase contrast image in theX-ray imaging apparatus 201A.
図24は、X線撮影装置201Aにおける位相コントラスト画像の生成方法の他の例を示す。 [Analysis method 2]
FIG. 24 shows another example of a method for generating a phase contrast image in the
第1の吸収型格子31の格子ピッチ方向(x方向)に並ぶ複数の画素を単位とし、単位毎に、その単位を構成する複数の画素の信号値Iを補間する。図示の例では、複数の画素の信号値を正弦曲線により補間したものであり、正弦曲線による補間は少なくとも3点あれば足りるため、互いに隣り合う3つの画素を単位としている。G1像のパターン周期p1’と画素40の配列ピッチPとが画像にモアレを生じさせる関係にある場合に、単位毎に、その単位を構成する複数の画素の信号値Iを補間してなる信号波形の周期は、モアレ周期Tとなる。
A plurality of pixels arranged in the lattice pitch direction (x direction) of the first absorption type lattice 31 is used as a unit, and the signal value I of the plurality of pixels constituting the unit is interpolated for each unit. In the illustrated example, signal values of a plurality of pixels are interpolated by a sine curve, and at least three points are sufficient for interpolation by the sine curve, and therefore, three adjacent pixels are used as a unit. When the pattern period p 1 ′ of the G1 image and the arrangement pitch P of the pixels 40 are in a relationship that causes moiré in the image, the signal values I of a plurality of pixels constituting the unit are interpolated for each unit. The period of the signal waveform is a moire period T.
上述した通り、G1像は、被写体HでのX線の屈折により、その屈折角φに応じた量だけx方向に変位することになる。そして、G1像がx方向にΔxだけ変位すると、それに伴って、モアレもまたx方向にΔXだけ変位し、信号波形の位相が変化する。被写体Hが存在しない場合の信号波形(FIG.24A)と、被写体Hが存在する場合の信号波形(FIG.24B)との両者の波形の位相差が、その単位に含まれる画素の信号の位相ズレ量ψに対応する。各画素の信号の位相ズレ量ψから式(31)を用いて屈折角φが求まり、式(30)を用いて位相シフト分布Φ(x)の微分量が求まるから、これをxについて積分することにより、被写体Hの位相シフト分布Φ(x)、すなわち被写体Hの位相コントラスト画像を生成する。
As described above, the G1 image is displaced in the x direction by an amount corresponding to the refraction angle φ due to refraction of X-rays at the subject H. When the G1 image is displaced by Δx in the x direction, the moire is also displaced by ΔX in the x direction, and the phase of the signal waveform changes. The phase difference between the waveform of the signal waveform (FIG. 24A) when the subject H is not present and the signal waveform (FIG. 24B) when the subject H is present is the phase of the signal of the pixel included in the unit. This corresponds to the displacement amount ψ. The refraction angle φ is obtained from the phase shift amount ψ of the signal of each pixel using the equation (31) and the differential amount of the phase shift distribution Φ (x) is obtained using the equation (30), and this is integrated with respect to x. Thus, the phase shift distribution Φ (x) of the subject H, that is, the phase contrast image of the subject H is generated.
なお、第1の吸収型格子31の格子ピッチ方向(x方向)とX線画像検出器230Aにおける画素40の配列における行方向又は列方向とが一致しているものとして、第1の吸収型格子31の格子ピッチ方向、つまりはG1像の周期的強度分布のパターン周期方向に並ぶ3つの画素を一単位とするものとして説明したが、G1像の周期的強度分布のパターン周期方向に対して、画素40の配列における行方向及び列方向がいずれも交差するように、第1の吸収型格子31とX線画像検出器230Aとが、光軸Cを中心として相対的に回転して配置されていてもよい。
Note that the first absorption-type grating is assumed that the grating pitch direction (x-direction) of the first absorption-type grating 31 coincides with the row direction or the column direction in the arrangement of the pixels 40 in the X-ray image detector 230A. Although the description has been made assuming that the three pixels arranged in the lattice pitch direction of 31, that is, the pattern period direction of the periodic intensity distribution of the G1 image, are taken as one unit, with respect to the pattern period direction of the periodic intensity distribution of the G1 image, The first absorption-type grating 31 and the X-ray image detector 230A are arranged so as to rotate relatively around the optical axis C so that both the row direction and the column direction in the arrangement of the pixels 40 intersect. May be.
〔解析方法3〕
X線撮影装置201Aにおいても、図21に示すX線撮影装置201と同様に、フーリエ変換及び逆フーリエ変換を用いて画像の周期パターンを解析し、位相コントラスト画像を生成することもできる。なお、この場合に、画像の周期パターンは、図21に示すX線撮影装置201においては、G1像の周期的強度分布に対応するが、本X線撮影装置201Aにおいては、G1像の周期的強度分布とX線画像検出器230Aの画素40の周期的配列との干渉に起因するモアレに対応する。 [Analysis method 3]
Similarly to theX-ray imaging apparatus 201 shown in FIG. 21, the X-ray imaging apparatus 201A can also generate a phase contrast image by analyzing the periodic pattern of an image using Fourier transform and inverse Fourier transform. In this case, the periodic pattern of the image corresponds to the periodic intensity distribution of the G1 image in the X-ray imaging apparatus 201 shown in FIG. 21, but the periodic pattern of the G1 image in the X-ray imaging apparatus 201A. This corresponds to moire caused by interference between the intensity distribution and the periodic arrangement of the pixels 40 of the X-ray image detector 230A.
X線撮影装置201Aにおいても、図21に示すX線撮影装置201と同様に、フーリエ変換及び逆フーリエ変換を用いて画像の周期パターンを解析し、位相コントラスト画像を生成することもできる。なお、この場合に、画像の周期パターンは、図21に示すX線撮影装置201においては、G1像の周期的強度分布に対応するが、本X線撮影装置201Aにおいては、G1像の周期的強度分布とX線画像検出器230Aの画素40の周期的配列との干渉に起因するモアレに対応する。 [Analysis method 3]
Similarly to the
本X線撮影装置201Aによれば、G1像のパターン周期p1’とX線画像検出器230Aの画素ピッチPとの干渉によって、X線画像検出器230Aによって取得される画像にモアレを生じさせ、被写体Hに起因するモアレの変調に基づいて位相コントラスト画像を生成する。一般にX線画像検出器における画素が小さくなるほどにS/Nが低下する傾向にあるところ、微細なG1像の周期的強度分布を検出可能なほどにX線画像検出器における画素の配列ピッチを小さくする必要がなく、S/Nを確保して位相情報の検出精度を高めることができる。
According to the X-ray imaging apparatus 201A, the interference between the pattern period p 1 ′ of the G1 image and the pixel pitch P of the X-ray image detector 230A causes moire in the image acquired by the X-ray image detector 230A. Then, a phase contrast image is generated based on the moire modulation caused by the subject H. In general, the S / N tends to decrease as the pixels in the X-ray image detector become smaller. Therefore, the pixel arrangement pitch in the X-ray image detector becomes smaller to detect the periodic intensity distribution of the fine G1 image. Therefore, it is possible to secure the S / N and improve the detection accuracy of the phase information.
図25は、本発明の実施形態を説明するための放射線撮影装置の他の例の構成を示す。なお、上述したX線撮影装置1,101,201と共通する要素には、共通の符号を付することにより説明を省略あるいは簡略する。
FIG. 25 shows the configuration of another example of a radiation imaging apparatus for explaining the embodiment of the present invention. Note that elements common to the above-described X-ray imaging apparatuses 1, 101, and 201 are denoted by common reference numerals, and description thereof is omitted or simplified.
図25に示すX線撮影装置301は、X線照射部11と、第1及び第2の吸収型格子31,32並びにX線画像検出器30と、被写体台15とを支持しているアーム部材(第1の支持部材)61の他に、第1及び第2の吸収型格子31,32並びにX線画像検出器30と、被写体台15とを支持するアーム部材(第2の支持部材)361がスタンド13に設けられている点で、図1に示すX線撮影装置1と異なる。
An X-ray imaging apparatus 301 shown in FIG. 25 includes an arm member that supports the X-ray irradiation unit 11, the first and second absorption gratings 31 and 32, the X-ray image detector 30, and the subject table 15. In addition to (first support member) 61, first and second absorption gratings 31 and 32, X-ray image detector 30, and arm member (second support member) 361 that supports subject table 15. Is different from the X-ray imaging apparatus 1 shown in FIG.
被写体台15及びその鉛直方向下側(光軸Cに沿ってX線の進行方向に被写体台15よりも下流側)に位置する撮影部12を支持するためのアーム部材361は、第1の吸収型格子31の格子ピッチ方向(x方向)に沿って被写体台15の載置面に被写体Hを配置する際に影響を及ぼさないため、その配置に特に制限はないが、本X線撮影装置301において、アーム部材361は、第1の吸収型格子31におけるX線遮蔽部31bの延在方向(y方向)に、アーム部材61との間で第1及び第2の吸収型格子31,32並びにX線画像検出器30と、被写体台15とを挟むように配置されている。即ち、アーム部材361は、第1の吸収型格子31に関してアーム部材61とは反対側において、アーム部材61と同様に、第1の吸収型格子31をその格子ピッチ方向(x方向)に延長した領域を外れ、第1の吸収型格子31をそのX線遮蔽部31bの延在方向(y方向)に延長した領域を通って、鉛直方向に延在して設けられている。
The arm member 361 for supporting the subject table 15 and the imaging unit 12 positioned on the lower side in the vertical direction (downstream of the subject table 15 in the X-ray traveling direction along the optical axis C) has a first absorption. Since there is no influence when the subject H is arranged on the placement surface of the subject table 15 along the lattice pitch direction (x direction) of the mold lattice 31, there is no particular limitation on the arrangement, but the X-ray imaging apparatus 301 is not limited. The arm member 361 includes the first and second absorption gratings 31, 32 and the arm member 61 in the extending direction (y direction) of the X-ray shielding part 31 b in the first absorption grating 31. The X-ray image detector 30 and the subject table 15 are arranged so as to be sandwiched therebetween. That is, the arm member 361 extends the first absorption type lattice 31 in the lattice pitch direction (x direction) on the opposite side of the first absorption type lattice 31 from the arm member 61 in the same manner as the arm member 61. The first absorption type grating 31 is provided so as to extend in the vertical direction through a region extending outside the region and extending in the extending direction (y direction) of the X-ray shielding portion 31b.
また、X線焦点18bや第1及び第2の吸収型格子31,32の相対位置のずれを防止ないし抑制する観点から、被写体台15は、衝撃や振動などを吸収ないし緩和する緩衝部材15bを介してアーム部材361に取り付けられている。
Further, from the viewpoint of preventing or suppressing the displacement of the relative positions of the X-ray focal point 18b and the first and second absorption gratings 31 and 32, the subject table 15 includes a buffer member 15b that absorbs or relaxes shock, vibration, and the like. The arm member 361 is attached.
本X線撮影装置301によれば、X線照射部11と、第1及び第2の吸収型格子31,32並びにX線画像検出器30と、被写体台15との支持を複数の支持部材(アーム部材61及びアーム部材361)に分けることにより、各支持部材に作用する負荷が軽減され、各支持部材の変形が防止ないし抑制される。それにより、支持部材の変形に起因するX線焦点18bや第1及び第2の吸収型格子31,32の相対位置のずれを防止ないし抑制することができ、被写体Hの位相情報の検出精度を高めることができる。
According to the X-ray imaging apparatus 301, the X-ray irradiation unit 11, the first and second absorption gratings 31 and 32, the X-ray image detector 30, and the subject table 15 are supported by a plurality of support members ( By dividing the arm member 61 and the arm member 361), the load acting on each support member is reduced, and deformation of each support member is prevented or suppressed. Thereby, the shift of the relative positions of the X-ray focal point 18b and the first and second absorption gratings 31 and 32 due to the deformation of the support member can be prevented or suppressed, and the detection accuracy of the phase information of the subject H can be improved. Can be increased.
また、アーム部材361は、第1の吸収型格子31におけるX線遮蔽部31bの延在方向(y方向)に、アーム部材61との間で第1及び第2の吸収型格子31,32並びにX線画像検出器30と、被写体台15とを挟むように配置されており、上述した縞走査法において、第2の吸収型格子32をx方向に並進移動させる際に、y方向の移動を規制して、x方向に確実に移動させることができる。
In addition, the arm member 361 includes the first and second absorption gratings 31, 32 and the arm member 61 in the extending direction (y direction) of the X-ray shielding portion 31 b in the first absorption grating 31. The X-ray image detector 30 and the object table 15 are arranged to be sandwiched between them. In the above-described fringe scanning method, when the second absorption grating 32 is translated in the x direction, the movement in the y direction is performed. It can be regulated and moved reliably in the x direction.
なお、本X線撮影装置301において、第1の格子は、吸収型格子に限られず位相型格子であってもよい。
In the X-ray imaging apparatus 301, the first grating is not limited to the absorption grating but may be a phase grating.
また、本X線撮影装置301において、そのX線照射部11に、上述したマルチスリット35(図19参照)を設けることができる。
Further, in the X-ray imaging apparatus 301, the X-ray irradiation unit 11 can be provided with the multi-slit 35 (see FIG. 19) described above.
図26は、図25のX線撮影装置301の変形例を示す。
FIG. 26 shows a modification of the X-ray imaging apparatus 301 of FIG.
図26に示すX線撮影装置は、図20に示すX線撮影装置101と同様に第1の吸収型格子31がX線照射部11と被写体台15との間に配置されており、そして、アーム部材361が、第2の吸収型格子32及びX線画像検出器30と、被写体台15とを支持している点で、図25に示すX線撮影装置301と異なる。
In the X-ray imaging apparatus shown in FIG. 26, the first absorption type grating 31 is disposed between the X-ray irradiation unit 11 and the subject table 15 like the X-ray imaging apparatus 101 shown in FIG. The arm member 361 is different from the X-ray imaging apparatus 301 shown in FIG. 25 in that the arm member 361 supports the second absorption type grating 32, the X-ray image detector 30, and the subject table 15.
なお、本例においても、第1の格子は吸収型格子に限られず位相型格子であってもよい。
In this example as well, the first grating is not limited to the absorption grating, but may be a phase grating.
また、本例においても、そのX線照射部11に、上述したマルチスリット35(図19参照)を設けることができる。
Also in this example, the multi-slit 35 (see FIG. 19) described above can be provided in the X-ray irradiation unit 11.
図27は、図25のX線撮影装置301の他の変形例を示す。
FIG. 27 shows another modification of the X-ray imaging apparatus 301 of FIG.
図27に示すX線撮影装置は、その撮影部が、図21に示すX線撮影装置201の撮影部212とされ、第1の吸収型格子31及びX線画像検出器230によって大略構成されており、そして、アーム部材361が、第1の吸収型格子31及びX線画像検出器230と、被写体台15とを支持している点で、図25に示すX線撮影装置301と異なる。
In the X-ray imaging apparatus shown in FIG. 27, the imaging unit is the imaging unit 212 of the X-ray imaging apparatus 201 shown in FIG. 21, and is roughly configured by the first absorption grating 31 and the X-ray image detector 230. In addition, the arm member 361 is different from the X-ray imaging apparatus 301 shown in FIG. 25 in that the first absorption grating 31, the X-ray image detector 230, and the subject table 15 are supported.
なお、本例においても、第1の格子は吸収型格子に限られず位相型格子であってもよい。
In this example as well, the first grating is not limited to the absorption grating, but may be a phase grating.
また、本例においても、そのX線照射部11に、上述したマルチスリット35(図19参照)を設けることができる。
Also in this example, the multi-slit 35 (see FIG. 19) described above can be provided in the X-ray irradiation unit 11.
また、本例においても、第1の吸収型格子31を、X線照射部11と被写体台15との間に配置することができる。
Also in this example, the first absorption grating 31 can be disposed between the X-ray irradiation unit 11 and the subject table 15.
図28は、本発明の実施形態を説明するための放射線撮影装置の他の例の構成を示す。なお、上述したX線撮影装置1,101,201と共通する要素には、共通の符号を付することにより説明を省略あるいは簡略する。
FIG. 28 shows the configuration of another example of a radiation imaging apparatus for explaining an embodiment of the present invention. Note that elements common to the above-described X-ray imaging apparatuses 1, 101, and 201 are denoted by common reference numerals, and description thereof is omitted or simplified.
図28に示すX線撮影装置401は、アーム部材61がX線照射部11と、第1及び第2の吸収型格子31,32並びにX線画像検出器30とを支持し、被写体台15が、このアーム部材61とは別の支持部材(第3の支持部材)461によって支持されている点で、図1に示すX線撮影装置1と異なる。即ち、本X線撮影装置401において、被写体台15は、X線撮影装置本体2から分離されている。
In the X-ray imaging apparatus 401 shown in FIG. 28, the arm member 61 supports the X-ray irradiation unit 11, the first and second absorption gratings 31 and 32, and the X-ray image detector 30. 1 differs from the X-ray imaging apparatus 1 shown in FIG. 1 in that it is supported by a support member (third support member) 461 different from the arm member 61. That is, in the X-ray imaging apparatus 401, the subject table 15 is separated from the X-ray imaging apparatus main body 2.
本X線撮影装置401によれば、被写体Hが被写体台15に載置された際の衝撃や、撮影中あるいは撮影間における被写体Hの動き(体動)による振動などが、X線照射部11及び撮影部12を支持するスタンド13に伝達されることを防止し、上記の通り、X線焦点18bや第1及び第2の吸収型格子31,32の相対位置のずれを防止ないし抑制することができ、被写体Hの位相情報の検出精度を高めることができる。
According to the present X-ray imaging apparatus 401, the X-ray irradiating unit 11 is subject to shock caused when the subject H is placed on the subject table 15, vibration due to movement (body movement) of the subject H during or during imaging. And the transmission to the stand 13 that supports the imaging unit 12, and as described above, the displacement of the relative positions of the X-ray focal point 18 b and the first and second absorption gratings 31 and 32 is prevented or suppressed. The detection accuracy of the phase information of the subject H can be improved.
なお、本X線撮影装置401において、第1の格子は、吸収型格子に限られず位相型格子であってもよい。
In the X-ray imaging apparatus 401, the first grating is not limited to the absorption grating but may be a phase grating.
また、本X線撮影装置401において、そのX線照射部11に、上述したマルチスリット35(図19参照)を設けることができる。
Further, in the X-ray imaging apparatus 401, the X-ray irradiation unit 11 can be provided with the multi slit 35 (see FIG. 19) described above.
図29は、図28のX線撮影装置401の変形例を示す。
FIG. 29 shows a modification of the X-ray imaging apparatus 401 of FIG.
図29に示すX線撮影装置は、図20に示すX線撮影装置101と同様に第1の吸収型格子31がX線照射部11と被写体台15との間に配置されている点で、図28に示すX線撮影装置401と異なる。被写体台15は、X線照射部11と、第1及び第2の吸収型格子31,32並びにX線画像検出器30とを支持するアーム部材61とは別の支持部材461によって支持されている。
The X-ray imaging apparatus shown in FIG. 29 is similar to the X-ray imaging apparatus 101 shown in FIG. 20 in that the first absorption grating 31 is disposed between the X-ray irradiation unit 11 and the subject table 15. Different from the X-ray imaging apparatus 401 shown in FIG. The subject table 15 is supported by a support member 461 different from the arm member 61 that supports the X-ray irradiation unit 11, the first and second absorption gratings 31 and 32, and the X-ray image detector 30. .
なお、本例においても、第1の格子は、吸収型格子に限られず位相型格子であってもよい。
In this example as well, the first grating is not limited to the absorption type grating but may be a phase type grating.
また、本においても、そのX線照射部11に、上述したマルチスリット35(図19参照)を設けることができる。
Also in the book, the multi-slit 35 (see FIG. 19) described above can be provided in the X-ray irradiation unit 11.
図30は、図28のX線撮影装置401の他の変形例を示す。
FIG. 30 shows another modification of the X-ray imaging apparatus 401 of FIG.
図30に示すX線撮影装置は、その撮影部が、図21に示すX線撮影装置201の撮影部212とされ、第1の吸収型格子31及びX線画像検出器230によって大略構成されている点で、図28に示すX線撮影装置401と異なる。被写体台15は、X線照射部11と、第1の吸収型格子31及びX線画像検出器230とを支持するアーム部材61とは別の支持部材461によって支持されている。
In the X-ray imaging apparatus shown in FIG. 30, the imaging unit is the imaging unit 212 of the X-ray imaging apparatus 201 shown in FIG. 21, and is roughly configured by the first absorption grating 31 and the X-ray image detector 230. It differs from the X-ray imaging apparatus 401 shown in FIG. The subject table 15 is supported by a support member 461 different from the arm member 61 that supports the X-ray irradiation unit 11, the first absorption type grating 31, and the X-ray image detector 230.
なお、本例においても、第1の格子は、吸収型格子に限られず位相型格子であってもよい。
In this example as well, the first grating is not limited to the absorption type grating but may be a phase type grating.
また、本例においても、そのX線照射部11に、上述したマルチスリット35(図19参照)を設けることができる。
Also in this example, the multi-slit 35 (see FIG. 19) described above can be provided in the X-ray irradiation unit 11.
また、本例においても、第1の吸収型格子31を、X線照射部11と被写体台15との間に配置することができる。
Also in this example, the first absorption grating 31 can be disposed between the X-ray irradiation unit 11 and the subject table 15.
図31は、本発明の実施形態を説明するための放射線撮影装置の他の例の構成を示す。なお、上述したX線撮影装置1,201と共通する要素には、共通の符号を付することにより説明を省略あるいは簡略する。
FIG. 31 shows the configuration of another example of the radiation imaging apparatus for explaining the embodiment of the present invention. Note that elements common to the above-described X-ray imaging apparatuses 1 and 201 are denoted by common reference numerals, and description thereof is omitted or simplified.
図31に示すX線撮影装置501は、X線照射部11がアーム部材61に支持されており、撮影部12及び被写体台15が、アーム部材61とは別にベース60に設けられた台座(第2の支持部材)561に支持されている点で、図1に示すX線撮影装置1と異なる。
In the X-ray imaging apparatus 501 shown in FIG. 31, the X-ray irradiation unit 11 is supported by an arm member 61, and the imaging unit 12 and the subject table 15 are provided on a base (first stage) provided separately from the arm member 61. 2), the X-ray imaging apparatus 1 shown in FIG.
被写体台15及びその鉛直方向下側(光軸Cに沿ってX線の進行方向に被写体台15よりも下流側)に位置する撮影部12を支持するための台座561は、第1の吸収型格子31の格子ピッチ方向(x方向)に沿って被写体台15の載置面に被写体Hを配置する際に影響を及ぼさず、よって、アーム部材61よりも剛性に優れた構造体として構成することができる。図示の例においては、台座561は、互いに連結された複数の脚部材によって構成されている。被写体台15は、台座561の上に緩衝部材15cを介して設置されている。
The pedestal 561 for supporting the imaging unit 12 located on the subject table 15 and the lower side in the vertical direction (downstream of the subject table 15 in the X-ray traveling direction along the optical axis C) is a first absorption type. The structure is not affected when the subject H is arranged on the placement surface of the subject table 15 along the lattice pitch direction (x direction) of the lattice 31, and is thus configured as a structure having higher rigidity than the arm member 61. Can do. In the illustrated example, the base 561 is configured by a plurality of leg members connected to each other. The subject table 15 is installed on a base 561 via a buffer member 15c.
以上のように、X線照射部11と、撮影部12と、被写体台15との支持を複数の支持部材(アーム部材61及び台座561)に分けることによって、各支持部材に作用する負荷が軽減され、各支持部材の変形が防止ないし抑制される。
As described above, by dividing the support of the X-ray irradiation unit 11, the imaging unit 12, and the subject table 15 into a plurality of support members (arm member 61 and base 561), the load acting on each support member is reduced. Thus, deformation of each support member is prevented or suppressed.
また、アーム部材61よりも剛性に優れる台座561により被写体台15を支持することによって、被写体台15に作用する衝撃や振動に起因するX線焦点18bや第1及び第2の吸収型格子31,32の相対位置のずれを、その剛構造によって防止ないし抑制することができ、被写体Hの位相情報の検出精度を高めることができる。
Further, by supporting the subject table 15 with a base 561 having higher rigidity than the arm member 61, the X-ray focal point 18b caused by the impact or vibration acting on the subject table 15, the first and second absorption gratings 31, The relative position shift of 32 can be prevented or suppressed by the rigid structure, and the detection accuracy of the phase information of the subject H can be improved.
なお、本X線撮影装置501において、第1の格子は、吸収型格子に限られず位相型格子であってもよい。
In the X-ray imaging apparatus 501, the first grating is not limited to the absorption grating but may be a phase grating.
また、本X線撮影装置501において、そのX線照射部11に、上述したマルチスリット35(図19参照)を設けることができる。
Moreover, in the X-ray imaging apparatus 501, the multi-slit 35 (see FIG. 19) described above can be provided in the X-ray irradiation unit 11.
図32は、図31のX線撮影装置501の変形例を示す。
FIG. 32 shows a modification of the X-ray imaging apparatus 501 of FIG.
図32に示すX線撮影装置は、その撮影部が、図21に示すX線撮影装置201の撮影部212とされ、第1の吸収型格子31及びX線画像検出器230によって大略構成されている点で、図31に示すX線撮影装置501と異なる。X線照射部11はアーム部材61に支持されており、撮影部212及び被写体台15は、アーム部材61とは別にベース60に設けられた台座561に支持されている
The X-ray imaging apparatus shown in FIG. 32 has an imaging unit that is an imaging unit 212 of the X-ray imaging apparatus 201 shown in FIG. 21, and is roughly configured by the first absorption grating 31 and the X-ray image detector 230. It differs from the X-ray imaging apparatus 501 shown in FIG. The X-ray irradiation unit 11 is supported by the arm member 61, and the imaging unit 212 and the subject table 15 are supported by a base 561 provided on the base 60 separately from the arm member 61.
なお、本例においても、第1の格子は、吸収型格子に限られず位相型格子であってもよい。
In this example as well, the first grating is not limited to the absorption type grating but may be a phase type grating.
また、本例においても、そのX線照射部11に、上述したマルチスリット35(図19参照)を設けることができる。
Also in this example, the multi-slit 35 (see FIG. 19) described above can be provided in the X-ray irradiation unit 11.
図33は、本発明の実施形態を説明するための、放射線撮影装置の他の例の構成を示す。なお、上述したX線撮影装置1と共通する要素には、共通の符号を付することにより説明を省略あるいは簡略する。
FIG. 33 shows a configuration of another example of the radiation imaging apparatus for explaining the embodiment of the present invention. In addition, description is abbreviate | omitted or simplified by attaching | subjecting a common code | symbol to the element which is common in the X-ray imaging apparatus 1 mentioned above.
上述したX線撮影装置1は、X線を略鉛直下方に向けて照射しており、基本的に臥位又は座位にて被写体Hの撮影を行うものであるが、図33に示すX線撮影装置601は、立位にて被写体Hの撮影を行うものであって、X線を略水平方向に照射する点で上述したX線撮影装置1と異なる。
The above-described X-ray imaging apparatus 1 irradiates X-rays substantially vertically downward, and basically performs imaging of the subject H in the supine position or the sitting position. The X-ray imaging shown in FIG. The apparatus 601 performs imaging of the subject H in a standing position, and differs from the X-ray imaging apparatus 1 described above in that X-rays are irradiated in a substantially horizontal direction.
X線撮影装置601では、X線照射部11、第1の吸収型格子31、第2の吸収型格子32、及びX線画像検出器30がこの順に略水平方向に並んで配置され、アーム部材61によって支持されている。アーム部材61は、第1の吸収型格子31をその格子ピッチ方向(z方向)に延長した領域を外れ、第1の吸収型格子31をそのX線遮蔽部31bの延在方向(y方向)に延長した領域を通って、略水平方向に延在する。
In the X-ray imaging apparatus 601, the X-ray irradiation unit 11, the first absorption type grating 31, the second absorption type grating 32, and the X-ray image detector 30 are arranged in this order in a substantially horizontal direction, and an arm member 61 is supported. The arm member 61 deviates from a region where the first absorption type grating 31 is extended in the grating pitch direction (z direction), and the first absorption type grating 31 extends in the extending direction of the X-ray shielding part 31b (y direction). It extends in a substantially horizontal direction through a region extending in the horizontal direction.
被写体台15は、そこに載置される被写体H(例えば膝関節)が、X線照射部11と第1の吸収型格子31との間に配置されるように設けられており、アーム部材61とは別の支持部材によって支持されている。
The subject table 15 is provided so that a subject H (for example, a knee joint) placed thereon is disposed between the X-ray irradiation unit 11 and the first absorption type grating 31, and the arm member 61. It is supported by another support member.
膝関節の撮影では、立位にて荷重が作用した状態での撮影ニーズが高いため、本X線撮影装置601のような立位型装置(横型装置)が好ましい。更に、本線撮影装置601では、アーム部材61が旋回軸62まわりに旋回可能に構成されており、アーム部材61を旋回させることによって被写体Hを種々の方向から撮影することができる。
In imaging of knee joints, there is a high need for imaging in a state where a load is applied in an upright position, and thus a standing type apparatus (lateral apparatus) such as the X-ray imaging apparatus 601 is preferable. Further, in the main line imaging apparatus 601, the arm member 61 is configured to be pivotable about the pivot axis 62, and the subject H can be photographed from various directions by pivoting the arm member 61.
なお、本X線撮影装置601においても、X線照射部11に上述したマルチスリット35(図19参照)を設けることができる。
In this X-ray imaging apparatus 601, the above-described multi slit 35 (see FIG. 19) can be provided in the X-ray irradiation unit 11.
また、本X線撮影装置601においても、上述したX線撮影装置101と同様に、第1の吸収型格子31を、X線照射部11と被写体台15に載置される被写体Hとの間に配置することができる。
Also in the X-ray imaging apparatus 601, as in the X-ray imaging apparatus 101 described above, the first absorption type grating 31 is placed between the X-ray irradiation unit 11 and the subject H placed on the subject table 15. Can be arranged.
また、本X線撮影装置601においても、上述したX線撮影装置201,201Aと同様に、第2の吸収型格子32を省略することができる。
Also in the X-ray imaging apparatus 601, the second absorption grating 32 can be omitted as in the X-ray imaging apparatuses 201 and 201A described above.
また、図34に示すように、アーム部材61に加えて、X線源11、第1の吸収型格子31、第2の吸収型格子32、及びX線画像検出器30を支持するアーム部材(第2の支持部材)661を設けてもよい。
Further, as shown in FIG. 34, in addition to the arm member 61, an arm member (supporting the X-ray source 11, the first absorption grating 31, the second absorption grating 32, and the X-ray image detector 30). A second support member 661 may be provided.
以上の説明においては、放射線として一般的なX線を用いる場合について説明したが、本発明はX線に限られるものではなく、α線、γ線等のX線以外の放射線を用いることも可能である。また、上述したX線撮影装置1以外の他のX線撮影装置についても、X線撮影装置1と同様に、第1の格子は吸収型格子に限らず位相型格子とすることもできる。
In the above description, the case where general X-rays are used as radiation has been described, but the present invention is not limited to X-rays, and radiation other than X-rays such as α-rays and γ-rays can also be used. It is. As for the X-ray imaging apparatus other than the X-ray imaging apparatus 1 described above, as in the X-ray imaging apparatus 1, the first grating is not limited to the absorption type grating but may be a phase type grating.
以上、説明したように、本明細書には、下記(1)~(34)の放射線撮影装置が開示されている。
As described above, the following (1) to (34) radiation imaging apparatuses are disclosed in this specification.
(1) 放射線照射部と、多数の線状体が配列されてなる周期的構造をそれぞれ有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む第1の放射線像を形成する第1の格子、及び前記第1の放射線像を部分的に遮蔽することによって周期的強度分布を含む第2の放射線像を形成する第2の格子と、前記第2の放射線像を検出して画像データを取得する放射線画像検出器と、前記放射線照射部、前記第1の格子、前記第2の格子、及び前記放射線画像検出器の並び方向に延在し、これら放射線照射部、第1の格子、第2の格子、及び放射線画像検出器を支持する第1の支持部材と、を備え、前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域、又は前記第2の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。
(2) 上記(1)の放射線撮影装置であって、前記放射線照射部と前記第1の格子との間に被写体が配置される放射線撮影装置。
(3) 上記(2)の放射線撮影装置であって、前記第1の格子、前記第2の格子、及び前記放射線画像検出器を支持する第2の支持部材を備える放射線撮影装置。
(4) 上記(3)の放射線撮影装置であって、前記第1の支持部材及び前記第2の支持部材は、前記第1の格子における線状体の延在方向に前記第1の格子、前記第2の格子、及び前記放射線画像検出器を間に挟んで、これら第1の格子、第2の格子、及び放射線画像検出器を支持している放射線撮影装置。
(5) 上記(3)又は(4)の放射線撮影装置であって、前記放射線照射部と前記第1の格子との間に配置され、被写体が載置される被写体台を備える放射線撮影装置。
(6) 上記(5)の放射線撮影装置であって、前記被写体台は、前記第1の支持部材、又は前記第1の支持部材及び前記第2の支持部材に支持されている放射線撮影装置。
(7) 上記(6)の放射線撮影装置であって、前記被写体台は、該被写体台に作用する力及び振動を緩衝する緩衝部材を介して、該被写体台を支持する支持部材に支持されている放射線撮影装置。
(8) 上記(2)から(4)のいずれか一つの放射線撮影装置であって、前記放射線照射部と前記第1の格子との間に配置され、被写体が載置される被写体台と、前記被写体台を支持する第3の支持部材と、を備える放射線撮影装置。
(9) 上記(1)の放射線撮影装置であって、前記第1の格子と前記第2の格子との間に被写体が配置される放射線撮影装置。
(10) 上記(9)の放射線撮影装置であって、前記第2の格子及び前記放射線画像検出器を支持する第2の支持部材を備える放射線撮影装置。
(11) 上記(10)の放射線撮影装置であって、前記第1の支持部材及び前記第2の支持部材は、前記第1の格子における線状体の延在方向に前記第2の格子及び前記放射線画像検出器を間に挟んで、これら第2の格子及び放射線画像検出器を支持している放射線撮影装置。
(12) 上記(10)又は(11)の放射線撮影装置であって、前記第1の格子と前記第2の格子との間に配置され、被写体が載置される被写体台を備える放射線撮影装置。
(13) 上記(12)の放射線撮影装置であって、前記被写体台は、前記第1の支持部材、又は前記第1の支持部材及び前記第2の支持部材に支持されている放射線撮影装置。
(14) 上記(13)の放射線撮影装置であって、前記被写体台は、該被写体台に作用する力及び振動を緩衝する緩衝部材を介して、該被写体台を支持する支持部材に支持されている放射線撮影装置。
(15) 上記(9)から(11)のいずれか一つの放射線撮影装置であって、前記第1の格子と前記第2の格子との間に配置され、被写体が載置される被写体台と、前記被写体台を支持する第3の支持部材と、を備える放射線撮影装置。
(16) 上記(1)から(15)のいずれか一つの放射線撮影装置であって、被写体を撮影して前記放射線画像検出器により取得される少なくとも一つの画像データを用いて位相コントラスト画像を生成する演算処理部を備える放射線撮影装置。
(17) 上記(16)の放射線撮影装置であって、前記第1の放射線像の周期的強度分布と前記第2の格子の周期的構造との重なり合いにおける位相関係が互いに異なる複数の相対位置関係に前記第1の格子及び前記第2の格子を配置する走査機構を備え、前記演算処理部は、前記第1の格子及び前記第2の格子の前記各相対位置関係のもとで被写体を撮影して前記放射線画像検出器により取得される複数の画像データを用いて位相コントラスト画像を生成する放射線撮影装置。
(18) 上記(17)の放射線撮影装置であって、前記走査機構は、前記第1の格子及び前記第2の格子のいずれか一方の格子を、その格子が配置される面内において、その格子における線状体の配列方向とは交差する方向に並進移動させ、前記各相対位置関係に前記第1の格子及び前記第2の格子を配置する放射線撮影装置。
(19) 上記(16)の放射線撮影装置であって、前記第2の放射線像の周期的強度分布は、前記第1の放射線像の周期的強度分布と前記第2の格子の周期的構造との重ね合わせによるモアレ縞を含んでおり、前記演算処理部は、被写体を撮影して前記放射線画像検出器により取得される一つの画像データを用い、該画像データにおける前記モアレ縞に対応した周期パターンに基づいて位相コントラスト画像を生成する放射線撮影装置。
(20) 上記(19)の放射線撮影装置であって、前記演算処理部は、前記モアレ縞と交差する方向に並ぶ3つ以上の複数の画素を一単位として、一単位を構成する前記複数の画素の信号値を補間してなる信号を演算し、被写体があるときと被写体がないときとの前記信号の位相ズレ量に基づいて位相コントラスト画像を生成する放射線撮影装置。
(21) 上記(19)の放射線撮影装置であって、前記演算処理部は、フーリエ変換を用いて前記画像データの空間周波数スペクトルを取得し、該空間周波数スペクトルから前記周期パターンの基本周波数成分を含む周波数領域を分離して、分離された前記周波数領域に対して逆フーリエ変換を行って位相コントラスト画像を生成する放射線撮影装置。
(22) 放射線照射部と、多数の線状体が配列されてなる周期的構造を有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む放射線像を形成する第1の格子と、前記放射線像を検出して画像データを取得する放射線画像検出器と、前記放射線照射部、前記第1の格子、及び前記放射線画像検出器の並び方向に延在し、これら放射線照射部、第1の格子、及び放射線画像検出器を支持する第1の支持部材と、を備え、前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。
(23) 上記(22)の放射線撮影装置であって、前記放射線照射部と前記第1の格子との間に被写体が配置される放射線撮影装置。
(24) 上記(23)の放射線撮影装置であって、前記第1の格子、及び前記放射線画像検出器を支持する第2の支持部材を備える放射線撮影装置。
(25) 上記(24)の放射線撮影装置であって、前記第1の支持部材及び前記第2の支持部材は、前記第1の格子における線状体の延在方向に前記第1の格子及び前記放射線画像検出器を間に挟んで、これら第1の格子及び放射線画像検出器を支持している放射線撮影装置。
(26) 上記(24)又は(25)の放射線撮影装置であって、前記放射線照射部と前記第1の格子との間に配置され、被写体が載置される被写体台を備える放射線撮影装置。
(27) 上記(26)の放射線撮影装置であって、前記被写体台は、前記第1の支持部材、又は前記第1の支持部材及び前記第2の支持部材に支持されている放射線撮影装置。
(28) 上記(27)の放射線撮影装置であって、前記被写体台は、該被写体台に作用する力及び振動を緩衝する緩衝部材を介して、該被写体台を支持する支持部材に支持されている放射線撮影装置。
(29) 上記(23)から(25)のいずれか一つの放射線撮影装置であって、前記放射線照射部と前記第1の格子との間に配置され、被写体が載置される被写体台と、前記被写体台を支持する第3の支持部材と、を備える放射線撮影装置。
(30) 上記(22)から(29)のいずれか一つの放射線撮影装置であって、被写体を撮影して前記放射線画像検出器により取得される少なくとも一つの画像データに含まれる周期パターンに基づいて位相コントラスト画像を生成する演算処理部を備える放射線撮影装置。
(31) 上記(30)の放射線撮影装置であって、前記放射線画像検出器は、前記放射線像の周期的強度分布を解像可能な解像度を有しており、前記周期パターンは、前記放射線像の周期的強度分布に対応する前記放射線撮影装置。
(32) 上記(30)の放射線撮影装置であって、前記放射線画像検出器は、前記放射線像の前記周期的強度分布の周期との関係でモアレを生じる解像度を有しており、前記周期パターンは、前記モアレに対応する放射線撮影装置。
(33) 放射線照射部と、多数の線状体が配列されてなる周期的構造をそれぞれ有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む第1の放射線像を形成する第1の格子、及び前記第1の放射線像を部分的に遮蔽することによって生じる周期的強度分布を含む第2の放射線像を形成する第2の格子と、前記第2の放射線像を検出して画像データを取得する放射線画像検出器と、前記放射線照射部、前記第1の格子、前記第2の格子、及び前記放射線画像検出器の並び方向に延在し、前記放射線照射部を支持する第1の支持部材と、前記第1の格子、前記第2の格子、及び前記放射線画像検出器を支持する第2の支持部材と、を備え、前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域、又は前記第2の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。
(34) 放射線照射部と、多数の線状体が配列されてなる周期的構造を有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む放射線像を形成する第1の格子と、前記放射線像を検出して画像データを取得する放射線画像検出器と、前記放射線照射部、前記第1の格子、及び前記放射線画像検出器の並び方向に延在し、前記放射線照射部を支持する第1の支持部材と、前記第1の格子及び前記放射線画像検出器を支持する第2の支持部材と、を備え、前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。 (1) A first radiation image including a radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and including a periodic intensity distribution through the radiation emitted from the radiation irradiation unit. A second grating that forms a second radiation image including a periodic intensity distribution by partially shielding the first radiation image, and the second radiation image. A radiation image detector for detecting and acquiring image data; and the radiation irradiating unit, the first grating, the second grating, and the radiation image detector extending in an arrangement direction of the radiation irradiating unit, And a first support member that supports the first grating, the second grating, and the radiation image detector, wherein the first support member places the first grating in the arrangement direction of the linear bodies. An extended region, or an array of linear bodies of the second lattice Radiation imaging apparatus arranged out of the extended area extending in the direction.
(2) The radiation imaging apparatus according to (1), wherein a subject is disposed between the radiation irradiation unit and the first lattice.
(3) The radiation imaging apparatus according to (2), further including a second support member that supports the first grating, the second grating, and the radiation image detector.
(4) The radiographic apparatus according to (3), wherein the first support member and the second support member are arranged in the first lattice in the extending direction of the linear body in the first lattice, A radiation imaging apparatus supporting the first grating, the second grating, and the radiation image detector with the second grating and the radiation image detector interposed therebetween.
(5) The radiographic apparatus according to the above (3) or (4), comprising a subject table disposed between the radiation irradiating unit and the first grating and on which a subject is placed.
(6) The radiographic apparatus according to (5), wherein the subject table is supported by the first support member, or the first support member and the second support member.
(7) In the radiographic apparatus according to (6), the subject table is supported by a support member that supports the subject table via a buffer member that buffers force and vibration acting on the subject table. Radiography equipment.
(8) The radiation imaging apparatus according to any one of (2) to (4), wherein the subject table is disposed between the radiation irradiating unit and the first lattice and on which a subject is placed; A radiation imaging apparatus comprising: a third support member that supports the subject table.
(9) The radiation imaging apparatus according to (1), wherein a subject is disposed between the first grating and the second grating.
(10) The radiographic apparatus according to (9), further including a second support member that supports the second grating and the radiographic image detector.
(11) The radiographic apparatus according to (10), wherein the first support member and the second support member are arranged in a direction in which a linear body extends in the first lattice, A radiation imaging apparatus supporting the second grating and the radiation image detector with the radiation image detector interposed therebetween.
(12) The radiation imaging apparatus according to (10) or (11), wherein the radiation imaging apparatus includes a subject table disposed between the first lattice and the second lattice and on which a subject is placed. .
(13) The radiographic apparatus according to (12), wherein the subject table is supported by the first support member, or the first support member and the second support member.
(14) In the radiographic apparatus according to (13), the subject table is supported by a support member that supports the subject table via a buffer member that buffers force and vibration acting on the subject table. Radiography equipment.
(15) The radiographic apparatus according to any one of (9) to (11), wherein the object table is disposed between the first grating and the second grating, and the object is placed thereon. A radiation imaging apparatus comprising: a third support member that supports the subject table.
(16) The radiographic apparatus according to any one of (1) to (15), wherein a phase contrast image is generated using at least one image data acquired by the radiographic image detector by imaging a subject. A radiation imaging apparatus including an arithmetic processing unit.
(17) The radiographic apparatus according to (16), wherein a plurality of relative positional relationships are different from each other in phase relationship in the overlap between the periodic intensity distribution of the first radiation image and the periodic structure of the second grating. A scanning mechanism for arranging the first grating and the second grating, and the arithmetic processing unit shoots a subject under the relative positional relationship between the first grating and the second grating. A radiation imaging apparatus that generates a phase contrast image using a plurality of image data acquired by the radiation image detector.
(18) In the radiographic apparatus according to (17), the scanning mechanism may include either one of the first grating and the second grating within a plane on which the grating is arranged. A radiation imaging apparatus in which the first grating and the second grating are arranged in the relative positional relationship by translationally moving in a direction intersecting the arrangement direction of the linear bodies in the grating.
(19) In the radiographic apparatus according to (16), the periodic intensity distribution of the second radiation image includes a periodic intensity distribution of the first radiation image and a periodic structure of the second grating. And the arithmetic processing unit uses one image data obtained by photographing the subject and acquired by the radiation image detector, and a periodic pattern corresponding to the moire fringes in the image data. Radiation imaging apparatus for generating a phase contrast image based on the above.
(20) In the radiographic apparatus according to (19), the arithmetic processing unit includes the plurality of pixels that constitute one unit, with three or more pixels arranged in a direction intersecting the moire fringe as one unit. A radiation imaging apparatus that calculates a signal obtained by interpolating pixel signal values and generates a phase contrast image based on a phase shift amount of the signal when there is a subject and when there is no subject.
(21) The radiographic apparatus according to (19), wherein the arithmetic processing unit obtains a spatial frequency spectrum of the image data using Fourier transform, and extracts a fundamental frequency component of the periodic pattern from the spatial frequency spectrum. A radiation imaging apparatus that separates a frequency region that includes the same, and performs an inverse Fourier transform on the separated frequency region to generate a phase contrast image.
(22) A radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and a radiation image including a periodic intensity distribution is formed by passing the radiation emitted from the radiation irradiation unit. 1 and a radiation image detector that detects the radiation image to acquire image data, the radiation irradiating unit, the first grating, and the radiation image detector extend in the arrangement direction of the radiation. An irradiation unit, a first grating, and a first support member that supports the radiation image detector, wherein the first support member extends the first grating in the arrangement direction of the linear bodies. A radiography apparatus arranged out of the extension area.
(23) The radiation imaging apparatus according to (22), wherein a subject is disposed between the radiation irradiation unit and the first lattice.
(24) The radiation imaging apparatus according to (23), further including a second support member that supports the first grating and the radiation image detector.
(25) In the radiographic apparatus according to (24), the first support member and the second support member are arranged in a direction in which a linear body extends in the first lattice, A radiation imaging apparatus supporting the first grating and the radiation image detector with the radiation image detector interposed therebetween.
(26) The radiation imaging apparatus according to (24) or (25), wherein the radiation imaging apparatus includes a subject table that is disposed between the radiation irradiation unit and the first lattice and on which a subject is placed.
(27) The radiation imaging apparatus according to (26), wherein the subject table is supported by the first support member, or the first support member and the second support member.
(28) In the radiographic apparatus according to (27), the subject table is supported by a support member that supports the subject table via a buffer member that buffers force and vibration acting on the subject table. Radiography equipment.
(29) The radiation imaging apparatus according to any one of (23) to (25), wherein the object table is disposed between the radiation irradiating unit and the first grating and on which an object is placed; A radiation imaging apparatus comprising: a third support member that supports the subject table.
(30) The radiation imaging apparatus according to any one of (22) to (29), wherein the subject is captured based on a periodic pattern included in at least one image data acquired by the radiation image detector. A radiation imaging apparatus including an arithmetic processing unit that generates a phase contrast image.
(31) The radiation imaging apparatus according to (30), wherein the radiation image detector has a resolution capable of resolving a periodic intensity distribution of the radiation image, and the periodic pattern is the radiation image. The radiographic apparatus corresponding to a periodic intensity distribution of
(32) The radiographic apparatus according to (30), wherein the radiological image detector has a resolution that generates moiré in relation to a period of the periodic intensity distribution of the radiographic image, and the periodic pattern Is a radiation imaging apparatus corresponding to the moire.
(33) A first radiation image that includes a radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and that includes a periodic intensity distribution through the radiation emitted from the radiation irradiation unit. A second grating forming a second radiation image including a periodic intensity distribution generated by partially shielding the first radiation image, and the second radiation image. A radiation image detector that detects image data and acquires image data; and the radiation irradiator that extends in an arrangement direction of the radiation irradiator, the first grating, the second grating, and the radiation image detector. A first support member that supports the first grating, the second grating, and a second support member that supports the radiation image detector, wherein the first support member includes An extension of the first lattice extending in the direction of arrangement of the linear bodies A radiation imaging apparatus arranged away from a long region or an extended region obtained by extending the second lattice in the arrangement direction of the linear bodies.
(34) A radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and a radiation image including a periodic intensity distribution is formed by passing the radiation emitted from the radiation irradiation unit. 1, a radiation image detector that detects the radiation image to acquire image data, the radiation irradiating unit, the first grating, and the radiation image detector extending in an arrangement direction of the radiation, A first support member that supports the irradiation unit; and a second support member that supports the first grating and the radiation image detector. The first support member includes the first grating. A radiation imaging apparatus arranged out of an extended region extending in the arrangement direction of the linear bodies.
(2) 上記(1)の放射線撮影装置であって、前記放射線照射部と前記第1の格子との間に被写体が配置される放射線撮影装置。
(3) 上記(2)の放射線撮影装置であって、前記第1の格子、前記第2の格子、及び前記放射線画像検出器を支持する第2の支持部材を備える放射線撮影装置。
(4) 上記(3)の放射線撮影装置であって、前記第1の支持部材及び前記第2の支持部材は、前記第1の格子における線状体の延在方向に前記第1の格子、前記第2の格子、及び前記放射線画像検出器を間に挟んで、これら第1の格子、第2の格子、及び放射線画像検出器を支持している放射線撮影装置。
(5) 上記(3)又は(4)の放射線撮影装置であって、前記放射線照射部と前記第1の格子との間に配置され、被写体が載置される被写体台を備える放射線撮影装置。
(6) 上記(5)の放射線撮影装置であって、前記被写体台は、前記第1の支持部材、又は前記第1の支持部材及び前記第2の支持部材に支持されている放射線撮影装置。
(7) 上記(6)の放射線撮影装置であって、前記被写体台は、該被写体台に作用する力及び振動を緩衝する緩衝部材を介して、該被写体台を支持する支持部材に支持されている放射線撮影装置。
(8) 上記(2)から(4)のいずれか一つの放射線撮影装置であって、前記放射線照射部と前記第1の格子との間に配置され、被写体が載置される被写体台と、前記被写体台を支持する第3の支持部材と、を備える放射線撮影装置。
(9) 上記(1)の放射線撮影装置であって、前記第1の格子と前記第2の格子との間に被写体が配置される放射線撮影装置。
(10) 上記(9)の放射線撮影装置であって、前記第2の格子及び前記放射線画像検出器を支持する第2の支持部材を備える放射線撮影装置。
(11) 上記(10)の放射線撮影装置であって、前記第1の支持部材及び前記第2の支持部材は、前記第1の格子における線状体の延在方向に前記第2の格子及び前記放射線画像検出器を間に挟んで、これら第2の格子及び放射線画像検出器を支持している放射線撮影装置。
(12) 上記(10)又は(11)の放射線撮影装置であって、前記第1の格子と前記第2の格子との間に配置され、被写体が載置される被写体台を備える放射線撮影装置。
(13) 上記(12)の放射線撮影装置であって、前記被写体台は、前記第1の支持部材、又は前記第1の支持部材及び前記第2の支持部材に支持されている放射線撮影装置。
(14) 上記(13)の放射線撮影装置であって、前記被写体台は、該被写体台に作用する力及び振動を緩衝する緩衝部材を介して、該被写体台を支持する支持部材に支持されている放射線撮影装置。
(15) 上記(9)から(11)のいずれか一つの放射線撮影装置であって、前記第1の格子と前記第2の格子との間に配置され、被写体が載置される被写体台と、前記被写体台を支持する第3の支持部材と、を備える放射線撮影装置。
(16) 上記(1)から(15)のいずれか一つの放射線撮影装置であって、被写体を撮影して前記放射線画像検出器により取得される少なくとも一つの画像データを用いて位相コントラスト画像を生成する演算処理部を備える放射線撮影装置。
(17) 上記(16)の放射線撮影装置であって、前記第1の放射線像の周期的強度分布と前記第2の格子の周期的構造との重なり合いにおける位相関係が互いに異なる複数の相対位置関係に前記第1の格子及び前記第2の格子を配置する走査機構を備え、前記演算処理部は、前記第1の格子及び前記第2の格子の前記各相対位置関係のもとで被写体を撮影して前記放射線画像検出器により取得される複数の画像データを用いて位相コントラスト画像を生成する放射線撮影装置。
(18) 上記(17)の放射線撮影装置であって、前記走査機構は、前記第1の格子及び前記第2の格子のいずれか一方の格子を、その格子が配置される面内において、その格子における線状体の配列方向とは交差する方向に並進移動させ、前記各相対位置関係に前記第1の格子及び前記第2の格子を配置する放射線撮影装置。
(19) 上記(16)の放射線撮影装置であって、前記第2の放射線像の周期的強度分布は、前記第1の放射線像の周期的強度分布と前記第2の格子の周期的構造との重ね合わせによるモアレ縞を含んでおり、前記演算処理部は、被写体を撮影して前記放射線画像検出器により取得される一つの画像データを用い、該画像データにおける前記モアレ縞に対応した周期パターンに基づいて位相コントラスト画像を生成する放射線撮影装置。
(20) 上記(19)の放射線撮影装置であって、前記演算処理部は、前記モアレ縞と交差する方向に並ぶ3つ以上の複数の画素を一単位として、一単位を構成する前記複数の画素の信号値を補間してなる信号を演算し、被写体があるときと被写体がないときとの前記信号の位相ズレ量に基づいて位相コントラスト画像を生成する放射線撮影装置。
(21) 上記(19)の放射線撮影装置であって、前記演算処理部は、フーリエ変換を用いて前記画像データの空間周波数スペクトルを取得し、該空間周波数スペクトルから前記周期パターンの基本周波数成分を含む周波数領域を分離して、分離された前記周波数領域に対して逆フーリエ変換を行って位相コントラスト画像を生成する放射線撮影装置。
(22) 放射線照射部と、多数の線状体が配列されてなる周期的構造を有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む放射線像を形成する第1の格子と、前記放射線像を検出して画像データを取得する放射線画像検出器と、前記放射線照射部、前記第1の格子、及び前記放射線画像検出器の並び方向に延在し、これら放射線照射部、第1の格子、及び放射線画像検出器を支持する第1の支持部材と、を備え、前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。
(23) 上記(22)の放射線撮影装置であって、前記放射線照射部と前記第1の格子との間に被写体が配置される放射線撮影装置。
(24) 上記(23)の放射線撮影装置であって、前記第1の格子、及び前記放射線画像検出器を支持する第2の支持部材を備える放射線撮影装置。
(25) 上記(24)の放射線撮影装置であって、前記第1の支持部材及び前記第2の支持部材は、前記第1の格子における線状体の延在方向に前記第1の格子及び前記放射線画像検出器を間に挟んで、これら第1の格子及び放射線画像検出器を支持している放射線撮影装置。
(26) 上記(24)又は(25)の放射線撮影装置であって、前記放射線照射部と前記第1の格子との間に配置され、被写体が載置される被写体台を備える放射線撮影装置。
(27) 上記(26)の放射線撮影装置であって、前記被写体台は、前記第1の支持部材、又は前記第1の支持部材及び前記第2の支持部材に支持されている放射線撮影装置。
(28) 上記(27)の放射線撮影装置であって、前記被写体台は、該被写体台に作用する力及び振動を緩衝する緩衝部材を介して、該被写体台を支持する支持部材に支持されている放射線撮影装置。
(29) 上記(23)から(25)のいずれか一つの放射線撮影装置であって、前記放射線照射部と前記第1の格子との間に配置され、被写体が載置される被写体台と、前記被写体台を支持する第3の支持部材と、を備える放射線撮影装置。
(30) 上記(22)から(29)のいずれか一つの放射線撮影装置であって、被写体を撮影して前記放射線画像検出器により取得される少なくとも一つの画像データに含まれる周期パターンに基づいて位相コントラスト画像を生成する演算処理部を備える放射線撮影装置。
(31) 上記(30)の放射線撮影装置であって、前記放射線画像検出器は、前記放射線像の周期的強度分布を解像可能な解像度を有しており、前記周期パターンは、前記放射線像の周期的強度分布に対応する前記放射線撮影装置。
(32) 上記(30)の放射線撮影装置であって、前記放射線画像検出器は、前記放射線像の前記周期的強度分布の周期との関係でモアレを生じる解像度を有しており、前記周期パターンは、前記モアレに対応する放射線撮影装置。
(33) 放射線照射部と、多数の線状体が配列されてなる周期的構造をそれぞれ有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む第1の放射線像を形成する第1の格子、及び前記第1の放射線像を部分的に遮蔽することによって生じる周期的強度分布を含む第2の放射線像を形成する第2の格子と、前記第2の放射線像を検出して画像データを取得する放射線画像検出器と、前記放射線照射部、前記第1の格子、前記第2の格子、及び前記放射線画像検出器の並び方向に延在し、前記放射線照射部を支持する第1の支持部材と、前記第1の格子、前記第2の格子、及び前記放射線画像検出器を支持する第2の支持部材と、を備え、前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域、又は前記第2の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。
(34) 放射線照射部と、多数の線状体が配列されてなる周期的構造を有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む放射線像を形成する第1の格子と、前記放射線像を検出して画像データを取得する放射線画像検出器と、前記放射線照射部、前記第1の格子、及び前記放射線画像検出器の並び方向に延在し、前記放射線照射部を支持する第1の支持部材と、前記第1の格子及び前記放射線画像検出器を支持する第2の支持部材と、を備え、前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。 (1) A first radiation image including a radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and including a periodic intensity distribution through the radiation emitted from the radiation irradiation unit. A second grating that forms a second radiation image including a periodic intensity distribution by partially shielding the first radiation image, and the second radiation image. A radiation image detector for detecting and acquiring image data; and the radiation irradiating unit, the first grating, the second grating, and the radiation image detector extending in an arrangement direction of the radiation irradiating unit, And a first support member that supports the first grating, the second grating, and the radiation image detector, wherein the first support member places the first grating in the arrangement direction of the linear bodies. An extended region, or an array of linear bodies of the second lattice Radiation imaging apparatus arranged out of the extended area extending in the direction.
(2) The radiation imaging apparatus according to (1), wherein a subject is disposed between the radiation irradiation unit and the first lattice.
(3) The radiation imaging apparatus according to (2), further including a second support member that supports the first grating, the second grating, and the radiation image detector.
(4) The radiographic apparatus according to (3), wherein the first support member and the second support member are arranged in the first lattice in the extending direction of the linear body in the first lattice, A radiation imaging apparatus supporting the first grating, the second grating, and the radiation image detector with the second grating and the radiation image detector interposed therebetween.
(5) The radiographic apparatus according to the above (3) or (4), comprising a subject table disposed between the radiation irradiating unit and the first grating and on which a subject is placed.
(6) The radiographic apparatus according to (5), wherein the subject table is supported by the first support member, or the first support member and the second support member.
(7) In the radiographic apparatus according to (6), the subject table is supported by a support member that supports the subject table via a buffer member that buffers force and vibration acting on the subject table. Radiography equipment.
(8) The radiation imaging apparatus according to any one of (2) to (4), wherein the subject table is disposed between the radiation irradiating unit and the first lattice and on which a subject is placed; A radiation imaging apparatus comprising: a third support member that supports the subject table.
(9) The radiation imaging apparatus according to (1), wherein a subject is disposed between the first grating and the second grating.
(10) The radiographic apparatus according to (9), further including a second support member that supports the second grating and the radiographic image detector.
(11) The radiographic apparatus according to (10), wherein the first support member and the second support member are arranged in a direction in which a linear body extends in the first lattice, A radiation imaging apparatus supporting the second grating and the radiation image detector with the radiation image detector interposed therebetween.
(12) The radiation imaging apparatus according to (10) or (11), wherein the radiation imaging apparatus includes a subject table disposed between the first lattice and the second lattice and on which a subject is placed. .
(13) The radiographic apparatus according to (12), wherein the subject table is supported by the first support member, or the first support member and the second support member.
(14) In the radiographic apparatus according to (13), the subject table is supported by a support member that supports the subject table via a buffer member that buffers force and vibration acting on the subject table. Radiography equipment.
(15) The radiographic apparatus according to any one of (9) to (11), wherein the object table is disposed between the first grating and the second grating, and the object is placed thereon. A radiation imaging apparatus comprising: a third support member that supports the subject table.
(16) The radiographic apparatus according to any one of (1) to (15), wherein a phase contrast image is generated using at least one image data acquired by the radiographic image detector by imaging a subject. A radiation imaging apparatus including an arithmetic processing unit.
(17) The radiographic apparatus according to (16), wherein a plurality of relative positional relationships are different from each other in phase relationship in the overlap between the periodic intensity distribution of the first radiation image and the periodic structure of the second grating. A scanning mechanism for arranging the first grating and the second grating, and the arithmetic processing unit shoots a subject under the relative positional relationship between the first grating and the second grating. A radiation imaging apparatus that generates a phase contrast image using a plurality of image data acquired by the radiation image detector.
(18) In the radiographic apparatus according to (17), the scanning mechanism may include either one of the first grating and the second grating within a plane on which the grating is arranged. A radiation imaging apparatus in which the first grating and the second grating are arranged in the relative positional relationship by translationally moving in a direction intersecting the arrangement direction of the linear bodies in the grating.
(19) In the radiographic apparatus according to (16), the periodic intensity distribution of the second radiation image includes a periodic intensity distribution of the first radiation image and a periodic structure of the second grating. And the arithmetic processing unit uses one image data obtained by photographing the subject and acquired by the radiation image detector, and a periodic pattern corresponding to the moire fringes in the image data. Radiation imaging apparatus for generating a phase contrast image based on the above.
(20) In the radiographic apparatus according to (19), the arithmetic processing unit includes the plurality of pixels that constitute one unit, with three or more pixels arranged in a direction intersecting the moire fringe as one unit. A radiation imaging apparatus that calculates a signal obtained by interpolating pixel signal values and generates a phase contrast image based on a phase shift amount of the signal when there is a subject and when there is no subject.
(21) The radiographic apparatus according to (19), wherein the arithmetic processing unit obtains a spatial frequency spectrum of the image data using Fourier transform, and extracts a fundamental frequency component of the periodic pattern from the spatial frequency spectrum. A radiation imaging apparatus that separates a frequency region that includes the same, and performs an inverse Fourier transform on the separated frequency region to generate a phase contrast image.
(22) A radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and a radiation image including a periodic intensity distribution is formed by passing the radiation emitted from the radiation irradiation unit. 1 and a radiation image detector that detects the radiation image to acquire image data, the radiation irradiating unit, the first grating, and the radiation image detector extend in the arrangement direction of the radiation. An irradiation unit, a first grating, and a first support member that supports the radiation image detector, wherein the first support member extends the first grating in the arrangement direction of the linear bodies. A radiography apparatus arranged out of the extension area.
(23) The radiation imaging apparatus according to (22), wherein a subject is disposed between the radiation irradiation unit and the first lattice.
(24) The radiation imaging apparatus according to (23), further including a second support member that supports the first grating and the radiation image detector.
(25) In the radiographic apparatus according to (24), the first support member and the second support member are arranged in a direction in which a linear body extends in the first lattice, A radiation imaging apparatus supporting the first grating and the radiation image detector with the radiation image detector interposed therebetween.
(26) The radiation imaging apparatus according to (24) or (25), wherein the radiation imaging apparatus includes a subject table that is disposed between the radiation irradiation unit and the first lattice and on which a subject is placed.
(27) The radiation imaging apparatus according to (26), wherein the subject table is supported by the first support member, or the first support member and the second support member.
(28) In the radiographic apparatus according to (27), the subject table is supported by a support member that supports the subject table via a buffer member that buffers force and vibration acting on the subject table. Radiography equipment.
(29) The radiation imaging apparatus according to any one of (23) to (25), wherein the object table is disposed between the radiation irradiating unit and the first grating and on which an object is placed; A radiation imaging apparatus comprising: a third support member that supports the subject table.
(30) The radiation imaging apparatus according to any one of (22) to (29), wherein the subject is captured based on a periodic pattern included in at least one image data acquired by the radiation image detector. A radiation imaging apparatus including an arithmetic processing unit that generates a phase contrast image.
(31) The radiation imaging apparatus according to (30), wherein the radiation image detector has a resolution capable of resolving a periodic intensity distribution of the radiation image, and the periodic pattern is the radiation image. The radiographic apparatus corresponding to a periodic intensity distribution of
(32) The radiographic apparatus according to (30), wherein the radiological image detector has a resolution that generates moiré in relation to a period of the periodic intensity distribution of the radiographic image, and the periodic pattern Is a radiation imaging apparatus corresponding to the moire.
(33) A first radiation image that includes a radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and that includes a periodic intensity distribution through the radiation emitted from the radiation irradiation unit. A second grating forming a second radiation image including a periodic intensity distribution generated by partially shielding the first radiation image, and the second radiation image. A radiation image detector that detects image data and acquires image data; and the radiation irradiator that extends in an arrangement direction of the radiation irradiator, the first grating, the second grating, and the radiation image detector. A first support member that supports the first grating, the second grating, and a second support member that supports the radiation image detector, wherein the first support member includes An extension of the first lattice extending in the direction of arrangement of the linear bodies A radiation imaging apparatus arranged away from a long region or an extended region obtained by extending the second lattice in the arrangement direction of the linear bodies.
(34) A radiation irradiation unit and a periodic structure in which a large number of linear bodies are arranged, and a radiation image including a periodic intensity distribution is formed by passing the radiation emitted from the radiation irradiation unit. 1, a radiation image detector that detects the radiation image to acquire image data, the radiation irradiating unit, the first grating, and the radiation image detector extending in an arrangement direction of the radiation, A first support member that supports the irradiation unit; and a second support member that supports the first grating and the radiation image detector. The first support member includes the first grating. A radiation imaging apparatus arranged out of an extended region extending in the arrangement direction of the linear bodies.
本発明によれば、第1の格子の線状体群の配列方向に沿って被写体を配置する際に、第1の支持部材が障害となることがなく、被写体を適切に配置して明瞭な位相コントラスト画像を得ることができる。
According to the present invention, when the subject is arranged along the arrangement direction of the linear body group of the first lattice, the first support member does not become an obstacle, and the subject is appropriately arranged to be clear. A phase contrast image can be obtained.
本発明を詳細にまた特定の実施態様を参照して説明したが、本発明の精神と範囲を逸脱することなく様々な変更や修正を加えることができることは当業者にとって明らかである。
本出願は、2011年12月5日出願の日本特許出願(特願2011-266163)、2012年10月24日出願の日本特許出願(特願2012-234988)に基づくものであり、その内容はここに参照として取り込まれる。 Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on Dec. 5, 2011 (Japanese Patent Application No. 2011-266163) and a Japanese patent application filed on Oct. 24, 2012 (Japanese Patent Application No. 2012-234888). Incorporated herein by reference.
本出願は、2011年12月5日出願の日本特許出願(特願2011-266163)、2012年10月24日出願の日本特許出願(特願2012-234988)に基づくものであり、その内容はここに参照として取り込まれる。 Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on Dec. 5, 2011 (Japanese Patent Application No. 2011-266163) and a Japanese patent application filed on Oct. 24, 2012 (Japanese Patent Application No. 2012-234888). Incorporated herein by reference.
1 X線撮影装置
2 X線撮影装置本体
3 コンソール
11 X線照射部
15 被写体台
18 X線管(X線源)
30 X線画像検出器
31 第1の吸収型格子(第1の格子)
31a 基板
31b X線遮蔽部(線状体)
32 第2の吸収型格子(第2の格子)
32a 基板
32b X線遮蔽部(線状体)
61 アーム部材(第1の支持部材) DESCRIPTION OFSYMBOLS 1 X-ray imaging apparatus 2 X-ray imaging apparatus main body 3 Console 11 X-ray irradiation part 15 Subject stand 18 X-ray tube (X-ray source)
30X-ray image detector 31 First absorption grating (first grating)
31a Substrate 31b X-ray shielding part (linear body)
32 Second absorption type grating (second grating)
32a Substrate 32b X-ray shielding part (linear body)
61 Arm member (first support member)
2 X線撮影装置本体
3 コンソール
11 X線照射部
15 被写体台
18 X線管(X線源)
30 X線画像検出器
31 第1の吸収型格子(第1の格子)
31a 基板
31b X線遮蔽部(線状体)
32 第2の吸収型格子(第2の格子)
32a 基板
32b X線遮蔽部(線状体)
61 アーム部材(第1の支持部材) DESCRIPTION OF
30
32 Second absorption type grating (second grating)
61 Arm member (first support member)
Claims (34)
- 放射線照射部と、
多数の線状体が配列されてなる周期的構造をそれぞれ有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む第1の放射線像を形成する第1の格子、及び前記第1の放射線像を部分的に遮蔽することによって周期的強度分布を含む第2の放射線像を形成する第2の格子と、
前記第2の放射線像を検出して画像データを取得する放射線画像検出器と、
前記放射線照射部、前記第1の格子、前記第2の格子、及び前記放射線画像検出器の並び方向に延在し、これら放射線照射部、第1の格子、第2の格子、及び放射線画像検出器を支持する第1の支持部材と、
を備え、
前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域、又は前記第2の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。 A radiation irradiation unit;
A first grating having a periodic structure in which a large number of linear bodies are arranged, and forming a first radiation image including a periodic intensity distribution by passing the radiation emitted from the radiation irradiation unit; And a second grating for forming a second radiation image including a periodic intensity distribution by partially shielding the first radiation image;
A radiation image detector for detecting the second radiation image and acquiring image data;
The radiation irradiation unit, the first grating, the second grating, and the radiation image detector extend in the arrangement direction, and the radiation irradiation unit, the first grating, the second grating, and the radiation image detection. A first support member for supporting the vessel;
With
The first support member is disposed away from an extended region in which the first lattice extends in the arrangement direction of the linear bodies, or an extended region in which the second lattice extends in the arrangement direction of the linear bodies. Radiography equipment. - 請求項1に記載の放射線撮影装置であって、
前記放射線照射部と前記第1の格子との間に被写体が配置される放射線撮影装置。 The radiation imaging apparatus according to claim 1,
A radiation imaging apparatus in which a subject is disposed between the radiation irradiating unit and the first grating. - 請求項2に記載の放射線撮影装置であって、
前記第1の格子、前記第2の格子、及び前記放射線画像検出器を支持する第2の支持部材を備える放射線撮影装置。 The radiographic apparatus according to claim 2,
A radiation imaging apparatus comprising: a second support member that supports the first grating, the second grating, and the radiation image detector. - 請求項3に記載の放射線撮影装置であって、
前記第1の支持部材及び前記第2の支持部材は、前記第1の格子における線状体の延在方向に前記第1の格子、前記第2の格子、及び前記放射線画像検出器を間に挟んで、これら第1の格子、第2の格子、及び放射線画像検出器を支持している放射線撮影装置。 The radiographic apparatus according to claim 3,
The first support member and the second support member are arranged between the first grating, the second grating, and the radiation image detector in the extending direction of the linear body in the first grating. A radiation imaging apparatus that supports the first grating, the second grating, and the radiation image detector with the sandwiched therebetween. - 請求項3又は4に記載の放射線撮影装置であって、
前記放射線照射部と前記第1の格子との間に配置され、被写体が載置される被写体台を備える放射線撮影装置。 The radiographic apparatus according to claim 3 or 4,
A radiation imaging apparatus comprising: a subject table disposed between the radiation irradiating unit and the first grid, on which a subject is placed. - 請求項5に記載の放射線撮影装置であって、
前記被写体台は、前記第1の支持部材、又は前記第1の支持部材及び前記第2の支持部材に支持されている放射線撮影装置。 The radiographic apparatus according to claim 5,
The radiographic apparatus in which the subject table is supported by the first support member or the first support member and the second support member. - 請求項6に記載の放射線撮影装置であって、
前記被写体台は、該被写体台に作用する力及び振動を緩衝する緩衝部材を介して、該被写体台を支持する支持部材に支持されている放射線撮影装置。 The radiographic apparatus according to claim 6,
The radiation imaging apparatus, wherein the subject table is supported by a support member that supports the subject table via a buffer member that buffers force and vibration acting on the subject table. - 請求項2から4のいずれか一項に記載の放射線撮影装置であって、
前記放射線照射部と前記第1の格子との間に配置され、被写体が載置される被写体台と、
前記被写体台を支持する第3の支持部材と、
を備える放射線撮影装置。 The radiographic apparatus according to any one of claims 2 to 4,
A subject table disposed between the radiation irradiating unit and the first grid and on which a subject is placed;
A third support member for supporting the subject table;
A radiographic apparatus comprising: - 請求項1に記載の放射線撮影装置であって、
前記第1の格子と前記第2の格子との間に被写体が配置される放射線撮影装置。 The radiation imaging apparatus according to claim 1,
A radiation imaging apparatus in which a subject is disposed between the first grating and the second grating. - 請求項9に記載の放射線撮影装置であって、
前記第2の格子及び前記放射線画像検出器を支持する第2の支持部材を備える放射線撮影装置。 The radiographic apparatus according to claim 9,
A radiation imaging apparatus comprising a second support member that supports the second grating and the radiation image detector. - 請求項10に記載の放射線撮影装置であって、
前記第1の支持部材及び前記第2の支持部材は、前記第1の格子における線状体の延在方向に前記第2の格子及び前記放射線画像検出器を間に挟んで、これら第2の格子及び放射線画像検出器を支持している放射線撮影装置。 The radiographic apparatus according to claim 10,
The first supporting member and the second supporting member sandwich the second grating and the radiation image detector in the extending direction of the linear body in the first grating, and these second supporting members A radiation imaging apparatus supporting a grating and a radiation image detector. - 請求項10又は11に記載の放射線撮影装置であって、
前記第1の格子と前記第2の格子との間に配置され、被写体が載置される被写体台を備える放射線撮影装置。 The radiographic apparatus according to claim 10 or 11,
A radiation imaging apparatus comprising: a subject table disposed between the first lattice and the second lattice, on which a subject is placed. - 請求項12に記載の放射線撮影装置であって、
前記被写体台は、前記第1の支持部材、又は前記第1の支持部材及び前記第2の支持部材に支持されている放射線撮影装置。 The radiographic apparatus according to claim 12,
The radiographic apparatus in which the subject table is supported by the first support member or the first support member and the second support member. - 請求項13に記載の放射線撮影装置であって、
前記被写体台は、該被写体台に作用する力及び振動を緩衝する緩衝部材を介して、該被写体台を支持する支持部材に支持されている放射線撮影装置。 The radiographic apparatus according to claim 13,
The radiation imaging apparatus, wherein the subject table is supported by a support member that supports the subject table via a buffer member that buffers force and vibration acting on the subject table. - 請求項9から11のいずれか一項に記載の放射線撮影装置であって、
前記第1の格子と前記第2の格子との間に配置され、被写体が載置される被写体台と、
前記被写体台を支持する第3の支持部材と、
を備える放射線撮影装置。 The radiographic apparatus according to any one of claims 9 to 11,
A subject table disposed between the first grid and the second grid and on which a subject is placed;
A third support member for supporting the subject table;
A radiographic apparatus comprising: - 請求項1に記載の放射線撮影装置であって、
被写体を撮影して前記放射線画像検出器により取得される少なくとも一つの画像データを用いて位相コントラスト画像を生成する演算処理部を備える放射線撮影装置。 The radiation imaging apparatus according to claim 1,
A radiation imaging apparatus including an arithmetic processing unit that images a subject and generates a phase contrast image using at least one image data acquired by the radiation image detector. - 請求項16に記載の放射線撮影装置であって、
前記第1の放射線像の周期的強度分布と前記第2の格子の周期的構造との重なり合いにおける位相関係が互いに異なる複数の相対位置関係に前記第1の格子及び前記第2の格子を配置する走査機構を備え、
前記演算処理部は、前記第1の格子及び前記第2の格子の前記各相対位置関係のもとで被写体を撮影して前記放射線画像検出器により取得される複数の画像データを用いて位相コントラスト画像を生成する放射線撮影装置。 The radiographic apparatus according to claim 16, wherein
The first grating and the second grating are arranged in a plurality of relative positional relationships in which the phase relationship in the overlap between the periodic intensity distribution of the first radiation image and the periodic structure of the second grating is different from each other. A scanning mechanism,
The arithmetic processing unit images a subject under the relative positional relationship between the first grating and the second grating and uses a plurality of image data acquired by the radiation image detector to perform phase contrast. A radiography device that generates images. - 請求項17に記載の放射線撮影装置であって、
前記走査機構は、前記第1の格子及び前記第2の格子のいずれか一方の格子を、その格子が配置される面内において、その格子における線状体の配列方向とは交差する方向に並進移動させ、前記各相対位置関係に前記第1の格子及び前記第2の格子を配置する放射線撮影装置。 The radiographic apparatus according to claim 17,
The scanning mechanism translates one of the first grating and the second grating in a direction intersecting the arrangement direction of the linear bodies in the grating in a plane where the grating is arranged. A radiation imaging apparatus that is moved and places the first grating and the second grating in the relative positional relationship. - 請求項16に記載の放射線撮影装置であって、
前記第2の放射線像の周期的強度分布は、前記第1の放射線像の周期的強度分布と前記第2の格子の周期的構造との重ね合わせによるモアレ縞を含んでおり、
前記演算処理部は、被写体を撮影して前記放射線画像検出器により取得される一つの画像データを用い、該画像データにおける前記モアレ縞に対応した周期パターンに基づいて位相コントラスト画像を生成する放射線撮影装置。 The radiographic apparatus according to claim 16, wherein
The periodic intensity distribution of the second radiation image includes moiré fringes due to superposition of the periodic intensity distribution of the first radiation image and the periodic structure of the second grating,
The arithmetic processing unit captures a subject, uses one piece of image data acquired by the radiation image detector, and generates a phase contrast image based on a periodic pattern corresponding to the moire fringes in the image data. apparatus. - 請求項19に記載の放射線撮影装置であって、
前記演算処理部は、前記モアレ縞と交差する方向に並ぶ3つ以上の複数の画素を一単位として、一単位を構成する前記複数の画素の信号値を補間してなる信号を演算し、被写体があるときと被写体がないときとの前記信号の位相ズレ量に基づいて位相コントラスト画像を生成する放射線撮影装置。 The radiographic apparatus according to claim 19, wherein
The arithmetic processing unit calculates a signal obtained by interpolating signal values of the plurality of pixels constituting one unit, with three or more pixels arranged in a direction intersecting the moire stripe as one unit, A radiation imaging apparatus that generates a phase contrast image based on a phase shift amount of the signal when there is an object and when there is no subject. - 請求項19に記載の放射線撮影装置であって、
前記演算処理部は、フーリエ変換を用いて前記画像データの空間周波数スペクトルを取得し、該空間周波数スペクトルから前記周期パターンの基本周波数成分を含む周波数領域を分離して、分離された前記周波数領域に対して逆フーリエ変換を行って位相コントラスト画像を生成する放射線撮影装置。 The radiographic apparatus according to claim 19, wherein
The arithmetic processing unit obtains a spatial frequency spectrum of the image data using Fourier transform, separates a frequency region including the fundamental frequency component of the periodic pattern from the spatial frequency spectrum, and separates the separated frequency region into the separated frequency region. A radiation imaging apparatus that generates a phase contrast image by performing inverse Fourier transform on the image. - 放射線照射部と、
多数の線状体が配列されてなる周期的構造を有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む放射線像を形成する第1の格子と、
前記放射線像を検出して画像データを取得する放射線画像検出器と、
前記放射線照射部、前記第1の格子、及び前記放射線画像検出器の並び方向に延在し、これら放射線照射部、第1の格子、及び放射線画像検出器を支持する第1の支持部材と、
を備え、
前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。 A radiation irradiation unit;
A first grating having a periodic structure in which a large number of linear bodies are arranged, and forming a radiation image including a periodic intensity distribution by passing the radiation emitted from the radiation irradiation unit;
A radiation image detector for detecting the radiation image and acquiring image data;
A first support member that extends in the arrangement direction of the radiation irradiation unit, the first grating, and the radiation image detector, and supports the radiation irradiation unit, the first grating, and the radiation image detector;
With
The first support member is a radiation imaging apparatus arranged so as to be out of an extended region obtained by extending the first lattice in the arrangement direction of the linear bodies. - 請求項22に記載の放射線撮影装置であって、
前記放射線照射部と前記第1の格子との間に被写体が配置される放射線撮影装置。 The radiation imaging apparatus according to claim 22,
A radiation imaging apparatus in which a subject is disposed between the radiation irradiating unit and the first grating. - 請求項23に記載の放射線撮影装置であって、
前記第1の格子、及び前記放射線画像検出器を支持する第2の支持部材を備える放射線撮影装置。 The radiographic apparatus according to claim 23, wherein
A radiation imaging apparatus comprising: a first support member that supports the first grating and the radiation image detector. - 請求項24に記載の放射線撮影装置であって、
前記第1の支持部材及び前記第2の支持部材は、前記第1の格子における線状体の延在方向に前記第1の格子及び前記放射線画像検出器を間に挟んで、これら第1の格子及び放射線画像検出器を支持している放射線撮影装置。 The radiographic apparatus according to claim 24, wherein
The first support member and the second support member sandwich the first lattice and the radiation image detector in the extending direction of the linear body in the first lattice, and the first support member and the second support member A radiation imaging apparatus supporting a grating and a radiation image detector. - 請求項24又は25に記載の放射線撮影装置であって、
前記放射線照射部と前記第1の格子との間に配置され、被写体が載置される被写体台を備える放射線撮影装置。 The radiographic apparatus according to claim 24 or 25, wherein:
A radiation imaging apparatus comprising: a subject table disposed between the radiation irradiating unit and the first grid, on which a subject is placed. - 請求項26に記載の放射線撮影装置であって、
前記被写体台は、前記第1の支持部材、又は前記第1の支持部材及び前記第2の支持部材に支持されている放射線撮影装置。 The radiographic apparatus according to claim 26, wherein
The radiographic apparatus in which the subject table is supported by the first support member or the first support member and the second support member. - 請求項27に記載の放射線撮影装置であって、
前記被写体台は、該被写体台に作用する力及び振動を緩衝する緩衝部材を介して、該被写体台を支持する支持部材に支持されている放射線撮影装置。 The radiographic apparatus according to claim 27, wherein
The radiation imaging apparatus, wherein the subject table is supported by a support member that supports the subject table via a buffer member that buffers force and vibration acting on the subject table. - 請求項23から25のいずれか一項に記載の放射線撮影装置であって、
前記放射線照射部と前記第1の格子との間に配置され、被写体が載置される被写体台と、
前記被写体台を支持する第3の支持部材と、
を備える放射線撮影装置。 The radiographic apparatus according to any one of claims 23 to 25, wherein
A subject table disposed between the radiation irradiating unit and the first grid and on which a subject is placed;
A third support member for supporting the subject table;
A radiographic apparatus comprising: - 請求項22に記載の放射線撮影装置であって、
被写体を撮影して前記放射線画像検出器により取得される少なくとも一つの画像データに含まれる周期パターンに基づいて位相コントラスト画像を生成する演算処理部を備える放射線撮影装置。 The radiation imaging apparatus according to claim 22,
A radiation imaging apparatus comprising: an arithmetic processing unit that images a subject and generates a phase contrast image based on a periodic pattern included in at least one image data acquired by the radiation image detector. - 請求項30に記載の放射線撮影装置であって、
前記放射線画像検出器は、前記放射線像の周期的強度分布を解像可能な解像度を有しており、
前記周期パターンは、前記放射線像の周期的強度分布に対応する前記放射線撮影装置。 The radiographic apparatus according to claim 30, wherein
The radiation image detector has a resolution capable of resolving a periodic intensity distribution of the radiation image,
The said radiographic apparatus with which the said periodic pattern respond | corresponds to the periodic intensity distribution of the said radiographic image. - 請求項30に記載の放射線撮影装置であって、
前記放射線画像検出器は、前記放射線像の前記周期的強度分布の周期との関係でモアレを生じる解像度を有しており、
前記周期パターンは、前記モアレに対応する放射線撮影装置。 The radiographic apparatus according to claim 30, wherein
The radiological image detector has a resolution that produces moiré in relation to the period of the periodic intensity distribution of the radiographic image,
The periodic pattern is a radiation imaging apparatus corresponding to the moire. - 放射線照射部と、
多数の線状体が配列されてなる周期的構造をそれぞれ有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む第1の放射線像を形成する第1の格子、及び前記第1の放射線像を部分的に遮蔽することによって生じる周期的強度分布を含む第2の放射線像を形成する第2の格子と、
前記第2の放射線像を検出して画像データを取得する放射線画像検出器と、
前記放射線照射部、前記第1の格子、前記第2の格子、及び前記放射線画像検出器の並び方向に延在し、前記放射線照射部を支持する第1の支持部材と、
前記第1の格子、前記第2の格子、及び前記放射線画像検出器を支持する第2の支持部材と、
を備え、
前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。 A radiation irradiation unit;
A first grating having a periodic structure in which a large number of linear bodies are arranged, and forming a first radiation image including a periodic intensity distribution by passing the radiation emitted from the radiation irradiation unit; And a second grating forming a second radiation image including a periodic intensity distribution caused by partially shielding the first radiation image;
A radiation image detector for detecting the second radiation image and acquiring image data;
A first support member that extends in the arrangement direction of the radiation irradiation unit, the first grating, the second grating, and the radiation image detector, and supports the radiation irradiation unit;
A second support member that supports the first grating, the second grating, and the radiation image detector;
With
The first support member is a radiation imaging apparatus arranged so as to be out of an extended region obtained by extending the first lattice in the arrangement direction of the linear bodies. - 放射線照射部と、
多数の線状体が配列されてなる周期的構造を有し、前記放射線照射部から放射された放射線を通過させて周期的強度分布を含む放射線像を形成する第1の格子と、
前記放射線像を検出して画像データを取得する放射線画像検出器と、
前記放射線照射部、前記第1の格子、及び前記放射線画像検出器の並び方向に延在し、前記放射線照射部を支持する第1の支持部材と、
前記第1の格子及び前記放射線画像検出器を支持する第2の支持部材と、
を備え、
前記第1の支持部材は、前記第1の格子をその線状体の配列方向に延長した延長領域から外れて配置されている放射線撮影装置。 A radiation irradiation unit;
A first grating having a periodic structure in which a large number of linear bodies are arranged, and forming a radiation image including a periodic intensity distribution by passing the radiation emitted from the radiation irradiation unit;
A radiation image detector for detecting the radiation image and acquiring image data;
A first support member that extends in an arrangement direction of the radiation irradiation unit, the first grating, and the radiation image detector, and supports the radiation irradiation unit;
A second support member for supporting the first grating and the radiation image detector;
With
The first support member is a radiation imaging apparatus arranged so as to be out of an extended region obtained by extending the first lattice in the arrangement direction of the linear bodies.
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