JP2009165902A - Phase contrast radiographic imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phase contrast radiographic imaging apparatus the dimention of which is the size capable of being arranged at a narrow place and which is free from the deterioration of image quality. <P>SOLUTION: The phase contrast radiographic imaging apparatus, which photographs an image by X-rays from an X-ray tube, includes: ophthalmic photographing apparatus focus size (D μm) not lower than 50 μm and not higher than 500 μm, the energy of the line spectrum of X-ray is not lower than 10 keV and not higher than 60 keV, and an anode made of molybdenum or rhodium; a digital detector to acquire an X-ray image penetrated through an object as electric signals; a fixing means to fix the object by defining the distance R1 (m) from the X-ray tube to the object to be within a range of the formula 10>R1≥(D-7)/200 (m) and the distance R2 from the object to the digital detector to be not lower than 0.15 m; a digital detector to acquire the X-ray image penetrated through the object as electric signals; and an image processing part to contract the X-ray image acquired by the digital detector to make it a full size image. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a phase-contrast radiographic image capturing apparatus, and more particularly to a phase-contrast radiographic apparatus that obtains a phase-contrast radiographic image by performing magnified imaging using a small-focus X-ray source.

The present applicant has already filed a patent application separately as Japanese Patent Application No. 2000-44381 regarding a phase contrast imaging method for obtaining a phase contrast radiation image using a small-focus X-ray source.
This phase-contrast imaging method shoots the subject and the detector away from each other, which inevitably results in magnified shooting, and the required detection compared to shooting with a conventional detector immediately after the subject (absorption contrast shooting). The area of the vessel increases.

  For example, the conventional chest dedicated machine for absorption contrast photography has been sufficient if it has a size of about 43 cm in length and breadth, but in the phase contrast photography method, in order to cope with double-magnification shooting, it is about 86 cm in length and breadth. A large area detector is required.

  Note that radiographic imaging using phase contrast is also described in Patent Document 1 below.

JP 2000-193609 A

  Such a large-area detector has been difficult to achieve with conventional methods. For example, in the case of an analog screen film system, a magnified photograph with a large area twice in length and width must be used as it is at the time of diagnosis, which increases the burden on the doctor.

In addition, the cassette used for photographing becomes large and difficult to handle, and the developing unit becomes too large to be installed indoors.
On the other hand, digital photographers such as CR (contributed radiography) using photostimulable phosphors and semiconductor detectors such as FPD (flat panel detectors) reduce the size of images obtained by enlargement photography. Since the data can be output, the doctor can make a diagnosis with an image having the same size as the conventional one, and the burden is not increased.

  However, in the case of CR, the laser scanning optical system capable of scanning a width of about 86 cm and the condensing optical system for guiding the stimulated emission to a photoelectric converter such as a photomultiplier become large, and the entire apparatus becomes large and expensive. Again, it is difficult to install in a room as compared with a conventional photographing apparatus.

Further, with regard to FPDs, increasing screen size leads to an increase in electrical noise and an increase in image defects.
The present invention provides an imaging apparatus for providing a large screen detector suitable for phase contrast imaging with a size that can be arranged even in a narrow imaging room, without deterioration in image quality, and at the same price as a conventional detector. Is to provide.

The present invention for solving the above problems is configured as follows.
(1) The invention according to claim 1 is a phase contrast radiographic image capturing apparatus that performs imaging using X-rays emitted from an X-ray tube, and has a focal spot size (D μm) of 50 μm or more and 500 μm or less, and an X-ray emission line An X-ray tube having a spectrum energy of 10 keV or more and 60 keV or less, an anode containing molybdenum or rhodium, a digital detector that acquires an X-ray image transmitted through the subject as an electrical signal, and the X-ray tube to the subject The subject is fixed by setting the distance R1 (m) within the range of the expression 10> R1 ≧ (D-7) / 200 (m) and the distance R2 from the subject to the digital detector being 0.15 m or more. A phase unit comprising: a fixing unit; and an image processing unit that reduces an X-ray image acquired by the digital detector to an actual size image. It is a contrast radiographic imaging device.

  (2) In the invention described in claim 2, the detection surface of the digital detector is divided into a plurality of small detectors, and the image processing unit is photographed by the plurality of small detectors in the detection means. The phase contrast radiographic image capturing apparatus according to claim 1, wherein a synthesized image is synthesized to obtain a comprehensive image.

(3) The invention according to claim 3 is the phase contrast radiographic image capturing apparatus according to claim 2, wherein the small detector is a stimulable phosphor plate.
(4) The invention according to claim 4 is the phase contrast radiographic image capturing device according to claim 3, wherein the photostimulable phosphor plate is arranged in a matrix of 2 × 2 or more. is there.

  (5) In the invention according to claim 5, each of the plurality of photostimulable phosphor plates is disposed so as to be in contact with an outer periphery of a large detector composed of the plurality of photostimulable phosphor plates. The phase contrast radiation image capturing apparatus according to claim 4, wherein the phase contrast radiation image capturing apparatus can be pulled out from an outer peripheral side.

  In these inventions, by combining the images detected by dividing by the small detector to obtain a comprehensive image, it is possible to suppress an increase in the size of the device accompanying an increase in the screen size, particularly in the depth direction. The size can be reduced to a size required for constructing one container.

  As a result, a large-screen detector suitable for the phase contrast imaging method can be realized at a price comparable to that of a conventional detector with a size that can be arranged even in a narrow imaging room and without deterioration in image quality.

  In these inventions, the above-mentioned small detector is constituted by a digital detector that acquires image information as an electrical signal, so that it is possible to reduce and output an image acquired by magnified shooting, which is the same as in the past. Since it is possible to interpret an image of a size (actual size image) and there is no increase in burden, it is more preferable.

  In these inventions, the small detector can be a stimulable phosphor plate, and the size and shape of the plate can be made compatible with the conventional cassette, and the user can replace the conventional cassette and its reader. Since it can be used as it is, it is not necessary to purchase a dedicated photographing apparatus such as an FPD, and the cost burden can be reduced.

  In these inventions, a detection surface having an arbitrary rectangular area can be formed by arranging photostimulable phosphor plates, which are small detectors, in a matrix of 2 × 2 or more. Therefore, it is possible to form a detection surface having an arbitrary large area using an existing photostimulable phosphor plate, which is suitable for imaging a phase contrast radiation image.

  In these inventions, if the photostimulable phosphor plate, which is a small detector, is arranged so as to be in contact with the outer periphery of the large detector composed of the plurality of photostimulable phosphor plates, the large detector Each can be pulled out from the outer peripheral side, and handling becomes simple.

  In these inventions, the stimulable phosphor plate, which is a small detector, is arranged so as to be in contact with the outer periphery of the large detector composed of the plurality of photostimulable phosphor plates, and in the horizontal direction. Can be pulled out in the horizontal direction on the outer periphery side of the large detector, and handling becomes even easier.

  As described above in detail, in the case of X-ray phase contrast imaging in which magnified imaging is performed with X-rays emitted from a small-focus X-ray source, the plurality of small detectors are divided into a plurality of small detectors. A large screen detector suitable for phase-contrast imaging can be placed even in a narrow imaging room by capturing images with a detector and combining the images captured by these small detectors to obtain a comprehensive image. In addition, it can be provided at the same price as a conventional detector without deterioration in image quality.

It is a block diagram which shows the structure of the phase contrast radiographic imaging apparatus of the 1st Example of this invention. It is explanatory drawing for the principle explanation of a phase contrast radiographic imaging device. It is explanatory drawing for the principle explanation of a phase contrast radiographic imaging device. It is explanatory drawing for description of a structure of a phase contrast radiographic imaging device X-ray image detector. It is explanatory drawing for description of a structure of a phase contrast radiographic imaging device X-ray image detector. It is a block diagram which shows the structure of the phase contrast radiographic imaging apparatus of the 2nd Example of this invention. It is a block diagram which shows the structure of the phase contrast radiographic imaging apparatus of the 2nd Example of this invention. It is a block diagram which shows the structure of the phase contrast radiographic imaging apparatus of the 2nd Example of this invention.

  Hereinafter, embodiments of the phase contrast radiographic image capturing apparatus of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the contents described in the embodiments.

  In the phase contrast radiographic image capturing apparatus of the present invention, phase contrast radiographic image data which is digital data is used. This phase contrast radiographic image data is obtained directly as a digital image, or obtained as an analog image is digitized. There are cases.

<Description of phase contrast radiation image>
This phase contrast radiation image is obtained by photographing with the apparatus of Japanese Patent Application No. 11-203969, the apparatus of Japanese Patent Application No. 11-266605, the apparatus of Japanese Patent Application No. 2000-44381, the apparatus of Japanese Patent Application No. 2000-53562, or the like. This is an image obtained by a photographing method such as the method of Japanese Patent Application No. 11-203969, the method of Japanese Patent Application No. 11-266605, or the method of Japanese Patent Application No. 2000-44381.

  As shown in FIG. 2, the device of Japanese Patent Application No. 2000-44381 is used to fix an X-ray source 1 that is a small-focus X-ray source that emits diverging X-rays and a subject 3 to the X-ray source 1. 2 and the X-ray image detector 4 for detecting an X-ray image transmitted through the object 3, and the blur width caused by the penumbra of the X-ray image is B (μm), as shown in FIGS. When the edge emphasis width by X-ray refraction contrast is E (μm), the subject holding tool is set so that 9E ≧ B when X-ray enlarged photographing is performed by transmitting X-rays irradiated from the X-ray tube to the subject. And an X-ray image photographing apparatus capable of installing an X-ray image detector.

  The method described in Japanese Patent Application No. 2000-44381 uses an X-ray source 1 that emits divergent X-rays, and transmits X-rays emitted from the X-ray source 1 to the subject 3 to perform X-ray enlarged imaging. X where the blur width due to the penumbra of the X-ray image obtained by this X-ray enlargement imaging is B (μm) and the edge enhancement width due to the X-ray refraction contrast is E (μm). This is a line image photographing method.

  In the apparatus and method described in Japanese Patent Application No. 2000-44381, the distance R1 between the X-ray source 1 and the subject 3 is set to 0.5 m or more, and the distance R2 between the subject and the X-ray image detector 4 is set to 1 m or more. The R1 + R2 is 5 m or less, the X-ray magnified imaging is 1.0 to 10 times, the focal size of the X-ray source 1 is 10 μm or more and 1000 μm or less, and the X-ray The focus size of the source 1 is not less than 30 μm and not more than 300 μm, the set tube voltage of the X-ray irradiated to the subject 3 is 50 to 150 kVp, the X-ray source 1 is a tungsten rotary anode X-ray tube, It is a more preferable aspect that the pixel size of the X-ray detector 4 is 1 μm or more and 200 μm or less.

  The edge emphasis width E can be expressed by the following three expressions, for example. Here, R1: X-ray source-subject distance (m), R2: Subject-X-ray image detector (m), λ: wavelength of maximum X-ray dose (10-10 m), A: subject is a cylinder. The diameter (mm) of the circle of the cross section at the time, δ: the refractive index difference between the object and air.

E = 39 × R2 (1 + 0.045 / R1) × λ ² × √A,
E = 27 × (1 + R2 / R1) ^1/3 × (λ ² × R2 × √A) ^2/3
E = 2.3 × (1 + R2 / R1) ^1/3 × (R2 × δ × √A) ^2/3
It becomes.

  The apparatus described in Japanese Patent Application No. 11-203969 includes an X-ray tube having a focal size (D μm) of 30 μm or more, a fixing means for fixing a subject position, and an X-ray detection for detecting an X-ray image transmitted through the subject. The fixing means includes a distance R1 (m) from the X-ray tube to the subject fixed by the fixing means within the range of the expression R1 ≧ (D-7) / 200 (m), and the fixing means The X-ray imaging apparatus is configured such that the distance R2 from the fixed subject to the X-ray detector can be set to 0.15 m or more.

In addition, the method described in Japanese Patent Application No. 11-203969 uses an X-ray detector to detect an X-ray image irradiated from an X-ray tube and transmitted through a subject, and reduces sharpness that is deteriorated by a penumbra. Is an X-ray image capturing method enhanced by image edge enhancement by the above, and an X-ray image capturing method using an X-ray tube having a focal spot size (D μm) of 30 μm or more, and a distance R1 from the X-ray tube to a subject (M)
R1 ≧ (D-7) / 200 (m),
And the distance R2 from the subject to the X-ray detector is 0.15 m or more.

  In the apparatus and method described in Japanese Patent Application No. 11-203969, the distance R1 is 10> R1 ≧ (D-7) / 200 (m), and 0.7 ≦ R1 ≦ 5 (m). The focus size of the X-ray tube is not less than 30 μm and not more than 1000 μm, the focus size of the X-ray tube is not less than 50 μm and not more than 500 μm, and the energy of the emission line spectrum of the X-ray irradiated to the subject is It is more preferable that it is 10 keV or more and 60 keV or less, the anode of the X-ray tube has molybdenum or rhodium, the pixel size of the X-ray detector is 1 μm or more and 200 μm or less, and the like.

  An apparatus described in Japanese Patent Application No. 11-266605 includes an object support device and a film cassette holder that can be moved and temporarily fixed on a support member, and includes a cooling X-ray tube and a film cassette holder. The distance between the screen and the film system can be 70 cm or more, and the distance between the subject of the subject supporting device and the screen and film system of the film cassette holder can be 20 cm or more. An X-ray imaging apparatus that captures an image.

  In addition, the method described in Japanese Patent Application No. 11-266605 includes a subject support device and a film cassette holder that are movable on a support member and can be temporarily fixed, and hold a cooling X-ray tube and a film cassette. X-ray imaging that captures X-ray refraction contrast images with a distance of 70 cm or more between the screen and film system of the tool, and a distance of 20 cm or more between the subject of the object support device and the screen and film system of the film cassette holder Is the method.

  The device of Japanese Patent Application No. 2000-53562 includes a small-focus radiation source that irradiates a subject with radiation, a holding member that holds the subject, a reading unit that reads radiation image information based on radiation transmitted through the subject, and a small-focus radiation source. A distance changing means for changing a first distance between the holding member and the second distance between the holding member and the reading means, and a control means for controlling the radiation conditions of the small focus radiation source, The control means is a radiographic image capturing apparatus that controls the radiation conditions of the small focus radiation source according to at least distance information regarding the first distance or the second distance, and the small focus radiation source that irradiates the subject with radiation, and the subject Holding member, reading means for reading radiation image information based on radiation transmitted through the subject, image display means or radiation image for displaying radiation image information A radiographic imaging apparatus having an image output means for outputting information, and having a control means for changing from an image enlargement ratio at the time of radiographic imaging and displaying radiographic image information by an image display means or outputting by an image output means is there.

  Absorption contrast radiography refers to imaging a subject in close contact with a detector and optionally via a grid. Absorption contrast radiographic images are images obtained by absorption contrast radiography.

  In addition, the phase contrast radiographic image capturing apparatus capable of directly obtaining the phase contrast radiographic image as a digital image is an apparatus capable of capturing the phase contrast radiographic image as well as the absorption contrast radiographic image capturing (ordinary general image capturing). There may be.

In the present invention, the drawings for explaining the embodiments are shown. However, each drawing is an example and the present invention is not limited to this.
<First embodiment>
First, an embodiment of the phase-contrast radiation image capturing apparatus described in the claims will be described.

FIG. 1 is a schematic diagram showing a configuration relating to an imaging portion of a first embodiment of a phase contrast radiographic image capturing apparatus.
The phase contrast radiographic image capturing apparatus according to the first embodiment is a phase contrast radiographic image capturing apparatus that performs magnified imaging with X-rays emitted from an X-ray source 1 that is a small focus X-ray source, and has a plurality of detection surfaces. The X-ray image detector 4 is divided into small detection surfaces.

  The X-ray image detector 4 includes a plurality of small detectors 5 (5a to 5f in FIGS. 4 and 5). The divided image obtained by reading each of the small detectors 5a to 5f with a normal reading unit is combined by an image processing unit (combining unit) to obtain a comprehensive image.

  As the X-ray source 1 which is a small focus X-ray source, a Mo tube, an Rh tube, a W tube, or the like is used. In phase contrast radiography, the tube has a small focal diameter and a high output. An x-ray source is desirable.

  As an example of high output, the rotating anode moves little by little while the electron beam is irradiated so that the electron beam irradiated to the rotating anode (target) does not hit the same position on the concentric circle of the rotating anode. The method of doing is conceivable. In order to capture a phase contrast radiation image, a radiation source having a radiation tube focal spot diameter of 30 to 500 μm and a maximum tube current of 50 mA or more is preferable.

  In this embodiment, by combining the images detected by being divided by the plurality of small detectors 5 to obtain a comprehensive image, an increase in the size of the apparatus accompanying the increase in the screen size of the X-ray image detector 4 is suppressed. In particular, the depth direction can be suppressed to a size necessary for constituting one small detector.

  As a result, a large-screen detector suitable for the phase contrast imaging method can be realized at a price comparable to that of a conventional detector with a size that can be arranged even in a narrow imaging room and without deterioration in image quality.

  In the first embodiment, the plurality of small detectors 5 can be used as stimulable phosphor plates, and the size and shape of the plates can be made compatible with conventional cassettes. Since the user can use the conventional cassette and its reader as it is, it is not necessary to purchase a dedicated photographing apparatus such as an FPD, and the cost burden can be reduced.

  In the first embodiment, the detection surface having an arbitrary rectangular area is formed by arranging the photostimulable phosphor plates, which are a plurality of small detectors, in a matrix of 2 × 2 or more. be able to.

  Therefore, it is possible to form a detection surface having an arbitrary large area using an existing photostimulable phosphor plate, which is suitable for imaging a phase contrast radiation image. FIG. 4 and FIG. 5 show examples arranged in a 2 × 3 matrix.

  Further, in the first embodiment, a stimulable phosphor plate, which is a plurality of small detectors, is replaced with a large detector (X-ray image detection) each composed of the plurality of stimulable phosphor plates. If it arrange | positions so that the outer periphery of the container 4) may be touched, it will become possible to draw out from the outer peripheral side of a large detector, respectively, and handling will become easy.

  In the first embodiment, the photostimulable phosphor plate, which is a small detector, is arranged so as to be in contact with the outer periphery of the large detector composed of the plurality of photostimulable phosphor plates. In addition, if it can be pulled out in the horizontal direction, it can be pulled out in the horizontal direction on the outer peripheral side of the large detector, and handling becomes easier.

  In the first embodiment, if the read pixel size is set to 100 μm or more and 500 μm or less on the detection surface, the resolution (double-magnification shooting) sufficient for outputting an enlarged image at an actual size is output. If it is, 50 to 250 μm) can be obtained, and the time required for image readout can be further shortened.

  In the first embodiment, the read pixel size is set to 200 μm or more and 400 μm or less within the above-mentioned range of 100 to 500 μm on the detection surface, so that the captured image is reduced to the actual size. In this case, it is possible to obtain a further sufficient resolution (100 to 200 μm in the case of double-magnification shooting), and further shorten the time required for image reading.

  In the imaging apparatus of FIG. 4 in which a plurality of small detectors 5 are configured by a stimulable phosphor plate, a 35.5 cm × 43.2 cm stimulable phosphor plate having a size of 3 × 2 × 6 , A large detector (X-ray image detector 4) of approximately 86.4 cm × 86.4 cm.

  Grooves as shown in FIG. 5 are formed in the case (large cassette) of the large detector, and the small detectors 5a to 5f can be pulled out in the horizontal direction. In the horizontal groove, the groove is slightly shifted in the front-rear direction, so that the left and right photostimulable phosphor plates can be arranged so as to overlap each other in the center.

  The arrangement of the photostimulable phosphor plate is not limited to this example, and various configurations are possible. In addition, after obtaining images from the small detectors 5a to 5f, by correcting and joining the overlapping portions by image processing in an image processing unit (not shown), a single seamless image is finally obtained. Obtainable.

<Second embodiment>
FIG. 6 is a schematic diagram showing a configuration of an imaging apparatus according to the second embodiment of the phase contrast radiographic imaging apparatus, and FIG. 7 is an X-ray image detector according to the second embodiment of the phase contrast radiographic imaging apparatus. FIG. 8 is a cross-sectional view showing a cross-sectional structure related to the X-ray image detector 6 of the second embodiment of the phase contrast radiographic image capturing apparatus.

  The phase contrast radiographic image capturing apparatus according to the second embodiment is a phase contrast radiographic image capturing apparatus that performs magnified imaging using X-rays emitted from an X-ray source 1 that is a small focus X-ray source, and has a plurality of detection surfaces. The X-ray image detector 6 includes a small detector, and the small detector in the X-ray image detector 6 includes a digital detector that acquires image information as an electrical signal.

  As the X-ray source 1 which is a small focus X-ray source, it is desirable to use the same X-ray source as that in the first embodiment described above. The divided image obtained by each digital detector is synthesized by the image processing unit 8 (combining means) to obtain a comprehensive image. This comprehensive image is supplied to the display 10 and the output device 11 via the network 9.

  6 shows an example using a 2 × 2 digital detector, FIG. 7 shows an example using a 6 × 6 digital detector, and FIG. 8 shows six digital detectors in the vertical direction. The example used is shown.

  The broken line in FIG. 7 is a line of the grating 60 of the radiation image detector 6, but is actually hidden from the protective member and the X-ray scintillator and cannot be seen from the front. FIG. 7 shows an example of 6 × 6 = 36 units, but the number is not limited to this.

  In this embodiment, by combining the images detected by dividing by a plurality of small detectors to obtain a comprehensive image, it is possible to suppress an increase in the size of the apparatus accompanying the increase in the screen size of the X-ray image detector 6. In particular, the depth direction can be suppressed to a size necessary for constituting one small detector. As a result, a large-screen detector suitable for the phase contrast imaging method can be realized at a price comparable to that of a conventional detector with a size that can be arranged even in a narrow imaging room and without deterioration in image quality.

  In this embodiment, the above-described small detector is configured by a digital detector that acquires image information as an electrical signal, so that it is possible to reduce and output an image acquired by enlarging photography. It is more preferable because an image having the same size as the conventional image (actual size image) can be read and the burden is not increased.

  The X-ray image detector 6 includes an X-ray scintillator 61, a lens array 62, and an area sensor 64 corresponding to each lens 63 of the lens array 62 arranged in this order. The X-ray scintillator 61 is protected by a protection member 65.

  Each lens 63 of the lens array 62 is supported by a lens support member 68, and a transparent member 66 is disposed between the X-ray scintillator 61 and the lens array 62. The area sensor 64 is supported by an area sensor support member 67.

  The shape, thickness, ray path, etc. of the components of the X-ray image detector 6 are not accurate. The grid 60 does not directly touch the X-ray scintillator 61 but abuts against the transparent member 66, thereby avoiding the grid 60 from hitting the X-ray scintillator 61 and being scratched, and the boundary line of the grid 60 being the boundary of the image. Prevents missing parts.

  FIG. 8 is a schematic cross-sectional view of the vertical cross section of the X image detector 6 and shows an example. Essential elements of the present invention are an X-ray scintillator 61, a lens array 62, and an area sensor 64. Since the lens array 62 and the area sensors 64 corresponding to the respective lenses 63 of the lens array 62 are arranged in this order, the number of pixels can be easily increased and the spatial resolution can be increased by using a plurality of area sensors. High image quality is possible. Further, since a plurality of area sensors are used, the focal length can be shortened, the thickness is small, the size is small, and the weight is light.

  By including gadolinium oxysulfide, cesium iodide, or the like as the material of the X-ray scintillator 61, the X-ray scintillator 61 emits visible light by exposure to X-rays, so that the spatial resolution can be increased and a high-quality image can be obtained. Obtainable.

  The lens array 62 is composed of a lens group composed of a combination of two or more different lenses 63. By using the lens group, it becomes easy to correct aberrations, and the spatial resolution is high and the image quality is high. Can be made thinner. The imaging magnification of the lens 63 is from 1 / 1.5 to 1/20. If the imaging magnification is greater than 1 / 1.5, the area sensor becomes too large to be disposed, and if less than 1/20, X The distance from the line scintillator 61 to the lens increases, and the thickness of the X-ray image detector 6 increases.

  As described above, in this embodiment, the small detector is composed of the scintillator 61, the optical image transfer means (lens 63), and the area sensor 64, and is thin, has no movable parts, and has a small detector. A large detector that does not require user operations such as loading and unloading can be obtained.

  With this configuration, basically, a large screen can be realized by simply arranging a single detector composed of a set of scintillators, an optical image transfer means (lens), and an area sensor, vertically and horizontally. There is an advantage that technical difficulties associated with the development do not occur.

  In this embodiment, since the optical image transfer means constituting the small detector is a lens unit composed of one or a plurality of lenses, a clear image is obtained when a reduction optical system is used. It can be obtained at low cost.

  In the second embodiment, if the read pixel size is set to 100 μm or more and 500 μm or less on the detection surface of the scintillator, the resolution (doubled) is sufficient when an enlarged photographed image is output at a reduced size. In the case of magnified shooting, 50 to 250 μm) can be obtained, and the time required for image readout can be shortened.

  In the first embodiment, the captured pixel size is set to 200 μm or more and 400 μm or less on the detection surface of the scintillator within the range of 100 to 500 μm described above, so that the photographed image is actual size. In the case of reduced output, it is possible to obtain a further sufficient resolution (100 to 200 μm in the case of double-magnification shooting), and further shorten the time required for image reading.

  In this second embodiment, a rectangular CCD is used as a digital detector, and 32 × 24 are arranged, so that a large detector (X-ray image detection) of approximately 86.4 cm × 86.4 cm. A device 6) was constructed. In this case, by setting the focal length of the lens unit to 8 mm, a thin structure with a small depth can be realized despite the large-area detector as a whole.

  As a result, a large-screen detector suitable for phase contrast imaging can be provided at a price comparable to that of a conventional detector, with a size that can be placed even in a narrow imaging room, without deterioration in image quality. .

1 X-ray source 3 Subject 4 X-ray image detector

Claims (5)

A phase-contrast radiographic imaging device that performs imaging with X-rays emitted from an X-ray tube,
An X-ray tube having a focal spot size (D μm) of 50 μm or more and 500 μm or less, an X-ray emission line spectrum energy of 10 keV or more and 60 keV or less, and an anode containing molybdenum or rhodium;
A digital detector that acquires an X-ray image transmitted through the subject as an electrical signal;
The distance R1 (m) from the X-ray tube to the subject is in the range of the equation 10> R1 ≧ (D-7) / 200 (m), and the distance R2 from the subject to the digital detector is Fixing means for fixing the subject at 0.15 m or more;
An image processing unit that reduces an X-ray image acquired by the digital detector to an actual size image;
A phase-contrast radiation image capturing apparatus. The digital detector has a detection surface divided into a plurality of small detectors,
The image processing unit synthesizes images captured by a plurality of small detectors in the detection unit to obtain a comprehensive image;
The phase-contrast radiation image capturing apparatus according to claim 1. The small detector is a stimulable phosphor plate;
The phase-contrast radiation image capturing apparatus according to claim 2. The stimulable phosphor plate is arranged in a matrix of 2 × 2 or more,
The phase-contrast radiation image capturing apparatus according to claim 3. The plurality of photostimulable phosphor plates are arranged so as to be in contact with the outer periphery of the large detector composed of the plurality of photostimulable phosphor plates, and can be drawn from the outer periphery side.
The phase-contrast radiation image capturing apparatus according to claim 4.

Images