JP2011092612A - Radiographic system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiographic system which utilizes an existing radiographic system introduced partly with additional equipment to allow long length radiography and to facilitate securing a duplicate area for subsequent image processing and obtaining information about a photographing position useful for image correction processing. <P>SOLUTION: The radiographic system includes a bucky device 11 and an irradiation position detecting means, wherein the bucky device 11 is provided with a first position controlling means 34 for controlling the position on a subject to irradiate with radiation, a supporting means for supporting movably a radiation detecting means 6, and a second position controlling means 14 for controlling variably the position of the radiation detecting means 6 supported by the supporting means against the subject; and the irradiation position detecting means detects either the relative positional relationship between the radiation irradiating means 31 and the radiation detecting means 6 or the positional relationship of a radiation irradiated by the radiation irradiating means 31 against the detecting surface of the radiation detecting means 6 in accordance with the relative positional relationship and the state of a collimator 32. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radiographic imaging system using digital radiation detection means.

  In recent years, a digital radiation image generating apparatus has been used as a method for irradiating a patient with radiation and detecting radiation transmitted through the patient to obtain a radiation image. As such a radiation image generating apparatus, there is a so-called FPD (Flat Panel Detector).

  An FPD is a two-dimensional array of a plurality of detection elements on a substrate. Radiation that has passed through a patient is irradiated on a phosphor (scintillator), and visible light that emits light according to the amount of irradiated radiation is emitted. A radiation image is obtained by converting the charges into charges by a detection element, accumulating them in a capacitor, and reading out the charges accumulated in the capacitor. In contrast to such a so-called indirect type FPD, a direct type FPD that directly irradiates a detection element with radiation that has passed through a subject and converts the amount of irradiated radiation into electric charge is also known.

  In recent years, a portable cassette type FPD equipped with a battery has been used as the FPD. The cassette type FPD is useful in terms of portability and the ability to immediately check the captured radiation image data. An imaging system including a wireless communication unit that wirelessly communicates with a cassette type FPD and a control device (console) that controls a radiation generation apparatus or associates captured image data with imaging order information is proposed Has been.

  By the way, in medical radiographic images, long-length imaging is performed for the purpose of grasping the entire subject (entire affected area) in whole leg imaging and whole spine imaging mainly for bone measurement. Conventionally, a long cassette for long photographing includes a CR plate using a plurality of sheet films and a stimulable phosphor, and is performed by one-time irradiation (for example, Patent Document 1).

  Furthermore, in order to perform long imaging with an FPD having a size smaller than the imaging area size, imaging is performed in a plurality of imaging areas in which a part of the imaging area is overlapped with one FPD, and a series of radiation obtained. There is a method of generating long image data by combining image data (for example, Patent Document 2).

JP 2000-267210 A US Pat. No. 7,177,455

  When combining a plurality of pieces of radiographic image data to generate long image data, it is necessary that adjacent radiographic image data include the same part as described above. Using this same part, the entire adjacent radiographic image data is aligned. However, since the imaging conditions such as the radiation irradiation angle at the time of each imaging are different, the image data of the same part is the adjacent image. The magnification and distortion (rectangular state) differ between data, and it is preferable to perform correction based on the information of these photographing conditions when performing composition processing.

  In particular, if the BUCKI device that supports the subject, the radiation irradiation device, the collimator device, and other radiation image capturing systems are all provided by the same manufacturer, the amount of overlapping portions when generating long image data However, it is relatively easy to align the respective shooting conditions, but it is difficult to use the systems of different manufacturers as a system.

  In view of such a problem, the present invention makes it possible to take a long image using an existing radiographic imaging system by additionally introducing some equipment without forcing the existing facility to update all equipment. It is intended to secure an overlapping area for subsequent image processing and acquire other imaging position information such as an X-ray optical axis position, an X-ray irradiation angle, and an SID useful for image correction processing. To do.

  The above object is achieved by the invention described below.

1. Radiation irradiating means for irradiating the subject with radiation;
Radiation detection means for acquiring image data by detecting radiation irradiated from the radiation irradiation means and transmitted through the subject; and
A collimator device comprising: an irradiation field limiting unit that limits an irradiation region of radiation irradiated from the radiation irradiation unit; and an irradiation field control unit that controls the irradiation field limiting unit;
First position control means for controlling a radiation irradiation position on a subject by controlling at least one of the radiation irradiation means and the collimator device;
A bookmarking device comprising: holding means for movably holding the radiation detection means; and second position control means for variably controlling the position of the radiation detection means held by the holding means relative to the subject;
The relative positional relationship between the radiation irradiating means and the radiation detecting means, or the relative positional relationship between the radiation irradiating means and the state of the collimator device detects the positional relation of the radiation irradiated by the radiation irradiating means with respect to the detection surface of the radiation detecting means. Irradiation position detection means;
A radiographic imaging system comprising:

  2. 2. The radiographic imaging system according to 1, wherein the irradiation position detection unit detects a radiation irradiation angle with respect to a detection surface of the radiation detection unit and a distance from the radiation irradiation unit.

3. In the long shooting in which a series of shooting is performed on the subject in a plurality of shooting areas, and the image data acquired in the plurality of shooting areas is combined to generate long image data,
3. The radiographic image capturing system according to item 2, wherein long image data is generated using detection data of the irradiation position detection unit of each image data.

  4). The radiographic imaging according to any one of claims 1 to 3, wherein the radiation detection means held by the holding means is moved by the second position control means in accordance with an output of the irradiation position detection means. system.

5. In the long shooting in which a series of shooting is performed on the subject in a plurality of shooting areas, and the image data acquired in the plurality of shooting areas is combined to generate long image data,
When adjusting the next photographing position with respect to one photographing position in the series of photographing, the radiation detecting means held by the holding means is moved by the second position control means based on the detection by the irradiation position detecting means. 5. The radiographic image capturing system as described in 4 above, wherein:

  According to the present invention, it is possible to take a long image using an existing radiographic imaging system by introducing a part of the equipment without forcing to update all equipment, and for subsequent image processing. As a result, it is possible to secure the overlapping area and acquire photographing position information useful for the image correction processing.

It is a figure which shows schematic structure of a radiographic imaging system. FIG. 2 is a perspective view of the FPD 6. It is the schematic which shows the radiation irradiation apparatus 3 and the imaging stand 11. FIG. It is a figure which shows the production | generation process of long image data. It is a figure which shows the control block of the collimator apparatus 32. FIG. It is a schematic diagram for demonstrating the positional relationship of the radiation irradiation apparatus 3 and FPD6. It is a control flowchart in long imaging performed by a radiographic imaging system. It is a control flowchart in long imaging performed by a radiographic imaging system. It is a schematic diagram explaining a distortion correction process. It is explanatory drawing which represents typically the positional relationship of the camera ca and marker M provided in the side of FPD6 in 1st Embodiment. It is a conceptual diagram explaining the position calculation method by the marker M. It is a figure which shows the relationship between 2 sets of markers M1 and M2 and the measurement position p1 of the camera ca. It is explanatory drawing which represents typically the positional relationship of the radiation irradiation apparatus 3 in 2nd Embodiment, and FPD6. It is explanatory drawing which represents typically the positional relationship of the radiation irradiation apparatus 3 in 3rd Embodiment, and FPD6. It is explanatory drawing which represents typically the positional relationship of the radiation irradiation apparatus 3 in 4th Embodiment, and FPD6. It is a control flowchart in long imaging performed by a radiographic imaging system.

  Although the present invention will be described based on an embodiment, the present invention is not limited to the embodiment.

  FIG. 1 is a diagram showing a schematic configuration of a radiographic image capturing system. As shown in the figure, the radiographic image capturing system includes a radiation irradiating device 3, a control BOX 4, an access point 5, a radiation detecting means 6, a console 7, an imaging table 11, and the like. The radiation irradiation device 3 and the imaging table 11 are provided inside the imaging room 100.

  The radiation detection means 6 (hereinafter simply referred to as FPD 6) incorporates detection elements arranged in a two-dimensional rectangular shape on a substrate. Radiation image data can be directly acquired based on the radiation dose irradiated from the radiation irradiation device 3 and transmitted through the patient P (subject). At the time of shooting, it is used by being mounted on the mounting port 11a of the shooting table 11. The FPD 6 is portable, has a built-in battery, and can perform wireless communication or wired communication. When performing wireless communication, communication is performed with each terminal connected to the network N via a wireless LAN (Local Area Network) via the access point 5.

  A console 7 is connected to the network N. The network N may be a communication line dedicated to the system, but is preferably an existing line such as Ethernet (registered trademark) because of the low degree of freedom of the system configuration.

  The console 7, the radiation irradiation device 3, and the control BOX 4 are connected and configured through a network N.

  The console 7 inputs an imaging order including information on a patient, an imaging affected area, and the like, and performs image processing on the radiation image data acquired by the FPD 6. In addition, the console 7 functions as an image processing device, and when performing long imaging (described later), a series of a plurality of pieces of radiation image data are combined to generate one piece of long image data.

  In addition, the system irradiates the illustration, but via a network N and HIS (Hospital Information System) that centrally manages patient diagnosis information and accounting information, and RIS (Radiology Information System) that manages information on radiation medical care It is connected.

  The radiation irradiation device 3 includes an irradiation unit 31 that irradiates radiation, a collimator device 32 including an irradiation field limiting unit that limits an irradiation field, an operation unit 34, an exposure button 35, and the like. Details of the collimator device 32 will be described later. Although not shown in FIG. 1, the radiographing room 100 includes a main room that is irradiated with radiation for imaging, and a front room that can avoid exposure due to irradiation. The shooting button 35 is disposed in the front chamber. The operation unit 34 sets an X-ray irradiation range, an X-ray dose to be irradiated, and the like. When the operator depresses the exposure button 35, X-ray irradiation is started on the patient P on the imaging table 11. At this time, rotation of the rotating anode of the irradiation unit 31 is started by a signal generated by depressing the exposure button 35, and after reaching a predetermined number of rotations and becoming steady rotation, a high voltage is applied to the filament to obtain X-rays. Start irradiation. When the exposure button 35 can be pressed twice, the rotation of the rotating anode starts when the first half-press is performed, and the FPD 6 is ready to be photographed (accumulation mode) by the second full-press. Only when the high voltage is applied to the filament so that the X-ray irradiation can be started and the FPD is not ready to be imaged, it is preferable that the X-ray irradiation is not permitted.

[FPD6]
The FPD 6 as radiation detection means will be described based on FIG. FIG. 2 is a perspective view of the FPD 6. As shown in FIG. 2, the FPD 6 includes a housing 601 that protects the inside, and is configured to be portable as a cassette. The power supply to each unit is performed by the battery 67 and the entire control is performed by the control unit 64. Inside the housing 601, a light emitting layer 63 and an imaging panel 62 are formed in layers from the detection surface side. The light emitting layer 63 emits light according to the intensity of incident radiation, and the imaging panel 62 converts the emitted light into an electrical signal.

  The light emitting layer 63 is generally called a scintillator layer. For example, a phosphor is a main component, and based on incident radiation, an electromagnetic wave having a wavelength of 300 nm to 800 nm, that is, an ultraviolet ray to an infrared ray centered on a visible ray. Outputs electromagnetic waves (light) over light.

  The electromagnetic wave (light) output from the light emitting layer is converted into electric energy and accumulated on the surface opposite to the surface on which the radiation of the light emitting layer is irradiated, and an image signal based on the accumulated electric energy is stored. An imaging panel 62 in which photoelectric conversion units that perform output are arranged in a matrix is formed. Note that a signal output from one photoelectric conversion unit is a signal corresponding to one pixel serving as a minimum unit constituting the radiation image data. The imaging panel 62 also includes a scanning drive circuit 609 that reads the stored electrical energy, and a signal selection circuit 608 that outputs the stored electrical energy as an image signal. The output image signal is stored in the memory 60.

[Radiation irradiation device 3, imaging table 11]
FIG. 3 is a schematic diagram showing the radiation irradiation device 3 and the imaging stand 11. The radiation irradiation device 3 controls an object by controlling at least one of an irradiation unit 31 that generates X-rays, a collimator device 32 that is attached to the front surface of the irradiation unit 31 and limits an X-ray irradiation field, the irradiation unit 31, and the collimator device 32. The first position control unit 34 functions as first position control means by controlling the irradiation position with respect to.

  The imaging table 11 (bukkake device) includes a mounting port 11a for mounting the FPD 6, a movable part 111 that functions as a holding means and provided with the mounting port 11a, a guide shaft 112 that supports the movable unit 111, and a patient P that is a subject. And a second position control unit 14 functioning as second position control means for controlling the movable unit 111. The FPD 6 is attached to the attachment port 11a. A connection terminal (not shown) is provided in the attachment port 11a, and power can be supplied from an external commercial power source and communication with other devices can be performed by the communication unit 69 through the connection terminal. In the case of the photographing stand 11 in which the connection port is not provided in the mounting opening 11a, power is supplied from the built-in battery 67 and the wireless communication is used.

  The guide shaft 112 extends along the body axis direction of the patient P supported by the support portion 113. The FPD 6 mounted on the movable portion 111 by the second control unit 14 is moved in the vertical direction along the guide shaft.

  In addition, in the example shown in FIG. 3 etc., although the collimator apparatus 32 and the irradiation part 31 are united and an irradiation angle is changed (swinging) in an arrow direction, it changes an irradiation area | region, but it is not restricted to this, When the angle of view from the X-ray is sufficiently large, the irradiation area may be changed by controlling only the collimator device 32 while the irradiation unit 31 is fixed. As another form, it is good also as a structure which moves an irradiation area | region by moving the irradiation part 31 and the collimator apparatus 32 to an up-down direction so that it may always face the image center of FPD6. 3 corresponds to an irradiation angle θ described later.

[Long shooting]
FIG. 4 is a diagram illustrating a process of generating long image data. 4A shows three pieces of radiation image data (G1) obtained by a series of imaging, and FIG. 4B shows a single long image by combining the images of FIG. This is an example in which the image data LG1 is generated, where long imaging refers to imaging in an imaging area wider than the imaging area size that can be imaged by one imaging in FPD. The imaging region is moved little by little to perform continuous imaging (referred to as a series of imaging), and a plurality of obtained radiographic image data is synthesized to generate one image data (long image data). .

  G1 in FIG. 4 is an imaging region of the thigh. The first position control unit 34 moves the irradiation region to the region 301 (see FIG. 3), and the second position control is performed at a position corresponding to the region. The image is taken by moving the FPD 6 by the unit 14. G2 and G3 correspond to the areas 302 and 303, respectively. G1, G2, and G3 are radiographic image data obtained by a series of continuous imaging for one patient. A part of the shooting area overlaps.

  The radiation image data obtained in FIG. 4A is transmitted to the console 7 by the communication unit 69. The console 7 detects the edge of the radiation irradiated part or the edge of the affected part based on the profile value of the image signal value or the differential value of the profile value due to the difference in density (radiation irradiation amount) in the overlapping region. The matching is performed by performing alignment between adjacent radiographic image data by matching edge portions detected in the overlapping region. Details will be described later with reference to FIG.

[Collimator device 32]
FIG. 5 is a diagram showing a control block of the collimator device 32. The collimator device 32 includes a detector such as a magnetic field sensor 326 that detects X-ray irradiation in order to synchronize the shift to the storage mode or reading mode of the FPD 6 with the X-ray irradiation timing, and the X-ray from the irradiation unit 31. An image is used to measure the positional relationship between the irradiation field limiting unit 327 for limiting the irradiation field of A, the AEC 328 for limiting the exposure dose (radiation dose) by X-rays, the communication unit 329 for communicating with other devices, and the FPD 6 The camera ca, the collimator device 32 and the radiation irradiation unit 31 integrated therewith, a triaxial inclination sensor gs for detecting the inclination with respect to at least the horizontal plane, a distance measuring sensor dws for measuring the distance from the FPD 6 by infrared rays, etc. A calculation unit 324 for calculating irradiation position information (described later) is provided.

  As the tilt sensor gs, a tilt with respect to a horizontal plane may be detected by detecting a change in angular velocity using a triaxial gyro sensor, or a direction with respect to gravity may be detected using a triaxial acceleration sensor. The inclination with respect to the horizontal plane may be detected.

[Position relationship with respect to detection surface of FPD6]
FIG. 6 is a schematic diagram for explaining the positional relationship between the radiation irradiation device 3 and the FPD 6. S is the detection surface of the FPD 6, and SID is the distance between the detection surface of the FPD 6 and the radiation irradiation device 3. hp is a reference surface and extends in a direction perpendicular to the detection surface S. In the present embodiment, since the detection surface S of the FPD 6 extends in the direction of gravity, the reference surface hp coincides with the horizontal plane. θ is an irradiation angle of X-rays irradiated from the radiation irradiation apparatus with respect to the reference plane hp. Further, ω is a rotation angle (adjustment amount) of the radiation irradiation device 3 for making the irradiation region on the reference surface hp substantially coincide with the detection surface S. Hereinafter, the distance SID, the irradiation angle θ, and the rotation angle ω are collectively referred to as “irradiation position information”. The calculation of the irradiation position information is performed by any one of (1) an image from the camera ca, (2) an inclination sensor gs, and position coordinates of the FPD 6 and the radiation irradiation device 3 (3) outputs of the inclination sensor gs and the distance measurement sensor dws. It can be carried out. Examples of (1) to (3) will be described later.

[Control flow]
7 and 8 are control flow charts in long imaging performed by the radiographic imaging system. This figure is a flow executed by the irradiation position detection means, the FPD 6, the console 7, the control BOX 4, and the like. The irradiation position detection means will be described with reference to FIGS.

  In step S10 of FIG. 7, preparation for imaging is performed. The patient P stands on the imaging table in accordance with the imaging conditions under the instruction of the imaging engineer, and the imaging engineer captures the imaging affected area and imaging area of the patient P in the long imaging. Perform alignment. In the following description, the imaging region is aligned by manually instructing an operation button or the like (not shown) that sends a signal to the first position control unit 34 and the second position control unit 14 by the imaging engineer. As will be described later, the control unit 14 inputs a start position (upper end) and an end position (lower end), and automatically sets the number of shots and the amount of movement between them by providing a predetermined overlapping area in the radiographic imaging system. An embodiment may be used in which control is performed so as to automatically calculate and move to the calculated imaging region.

  In step S11, the irradiation position is moved by the FPD 6 and the radiation irradiation device 3 in accordance with the imaging region set in step S10 by the operation instruction of the imaging engineer (first if it is the first image).

  In step S12, the irradiation position detection means obtains irradiation position information n of the nth sheet (first sheet if it is the first). The acquired irradiation position information n is stored in the memory of the console 7.

  In step S13, radiography image data (radiation image data G1 to G3 in the example of FIG. 5) is acquired by performing n-th imaging. Imaging is performed from a radiation irradiation device 3 at a predetermined intensity for a predetermined time, and the FPD 6 transitions from the reset state to the accumulation state in accordance with the start timing of the irradiation. The accumulated charge is read and radiation image data is generated. The generated radiation image data is stored in the memory 60. In the FPD 6, these timings are determined by using the operation of the exposure button 35 as a trigger or a signal from the magnetic field sensor 326, or if the FPD 6 has a built-in irradiation detection unit that detects the start and stop of radiation irradiation. The detection signal may be used.

  Steps S11 to S13 are repeated until all the series of continuous shootings in the long shooting are completed (step S14).

  In the present embodiment, the existing radiographic imaging system is used by adding some equipment by providing the collimator device 31 with the function of imaging position information detection means without forcing all equipment to be updated. Thus, it is possible to take a long image, obtain an overlapping area for subsequent image processing, and acquire shooting position information useful for image correction processing.

  FIG. 8 is a control flow executed following the control flow of FIG. In step S21, the console 7 acquires the radiation image data n from the memory 60 of the FPD 6, and reads the irradiation position information n when the radiation image data n stored in its own memory is imaged.

  In step S22, correction processing is executed on the radiation image data n using the irradiation position information n. The distortion correction process mainly uses the irradiation angle θ (when necessary, the rotation angle ω is used together), and the magnification correction process mainly uses the distance SID (when necessary, the irradiation angle θ is also used).

  FIG. 9 is a schematic diagram for explaining the distortion correction processing. FIG. 9A shows an image obtained when a rectangular object is photographed. As the irradiation angle θ increases (downward in FIG. 9A), the spread of X-rays irradiated from the radiation irradiation apparatus increases, and the image of the object increases accordingly. For this reason, the images G11, G12, and G13 become larger in order between the images, and the lower side of each image has a trapezoidal shape that is larger than the upper side. If the rotation angle ω is inappropriate, the trapezoidal shape changes to an irregular rectangular shape.

  By performing trapezoidal shape correction and magnification correction based on the information of the irradiation angle θ and the distance SID, the sizes of the images G11 to G13 can be made uniform as shown in FIG. 9B.

  Even when a subject having the same thickness is photographed, the length of passage of X-rays varies depending on the irradiation angle θ. In the base processing, in order to correct the difference in the X-ray dose reaching the detection surface due to the difference in the passing length, the density correction is performed by the irradiation angle θ.

  Steps S21 to S22 are repeated until the correction process is completed for all the series of radiation image data in the long imaging (step S23: No).

  When all the correction processes are completed (step S23: Yes), the radiographic image data after the correction process is synthesized to generate the long image data Lg.

  As described above, sufficient correction processing can be performed using the shooting position information obtained in the control flow of FIG. 7, and it is possible to perform the composition with high accuracy particularly in long shooting.

[Calculation of irradiation position information by irradiation position detection means]
First, the irradiation position detection means using the camera ca will be described as the “first embodiment”. In the first embodiment, the calculation unit 324 and the camera ca function as irradiation position detection means, and the calculation of the irradiation position information is performed by performing various processes on the image captured by the camera ca by the calculation unit 324. is there.

  FIG. 10 is an explanatory diagram schematically illustrating the positional relationship between the camera ca and the marker M provided on the side of the FPD 6 (outside the imaging region) in the first embodiment. The right side is a side view, and the left side is a front view of the FPD 6 and the mark M. The camera ca is provided integrally with the radiation irradiating device 3, and when the irradiating unit 31 of the radiation irradiating device 3 is moved by swinging or the like, the camera ca also moves together, so the optical axis of the camera ca and the irradiating unit A fixed relative positional relationship with the X-ray optical axis 31 is maintained. Since the marker M is provided on the FPD 6 or the movable portion 111 and moves with the movement of the FPD 6 mounted on the movable portion 111, the positional relationship with the FPD 6 is always kept constant.

  Strictly speaking, the optical axis of the camera ca of the collimator device 32 and the X-ray optical axis of the radiation irradiating device 3 cause a problem of parallax, but with respect to the parallax, (1) a half mirror is used as a collimator device. The optical axes of the two are made coincident with each other, or (2) the correction is made based on the relative position between the X-ray emission source and the camera ca inputted in advance, and the values of the distance SID and the irradiation angle θ. Good.

  When the marker M is copied within a predetermined area of the image photographed by the camera ca, the collimator device 32 assumes that the appropriate position for long photographing has been reached, and calculates irradiation position information. When the image of the mark M is projected outside the predetermined area, an operator such as an engineer adjusts the position of the collimator device 32 again because it is inappropriate to capture the image at that position. Further, the FPD 6 may be moved to the optimum position by the movable unit 111 within the appropriate position range or the like.

  FIG. 11 is a conceptual diagram illustrating a position calculation method using the marker M. Note that FIG. 10 shows an example of a pair of markers M, but FIG. 11 shows an example using three pairs of markers M. FIG. 11A is a schematic diagram showing the relationship between the imaging region a2 of the FPD 6 and the image a1 captured by the camera ca. As shown in the figure, each marker M is provided outside the imaging region a2. Depending on the positional relationship between the markers M1 to M3 in the area of the image a1 captured by the camera ca, the imaging engineer or the collimator device 32 has appropriate or inappropriate correspondence between the imaging area a2 of the FPD 6 and the irradiation area of the radiation irradiation apparatus 3. Can be determined. FIG. 11B illustrates the positional relationship between the three pairs of markers M1, M2, and M3 viewed from the front direction (irradiation angle θ is zero) at a predetermined distance. The distance and the positional relationship between the markers M are set to predetermined distances in advance. The center position of each marker M is calculated by performing image processing such as edge processing on the image of the camera ca, and the distance r between the markers M is calculated.

  The distance SID calculates the magnification coefficient α by measuring the length of the reference scale previously arranged on the detection surface in a predetermined positional relationship and the length of the reference scale on the image data of the camera ca. It can be calculated by multiplying the length of the object on the image data, for example, the distance r between the markers M (SID = α × r). FIG. 11C is a diagram showing the positional relationship of the three pairs of markers M in the image data taken from the lower side rather than the front. For convenience of explanation, the actual image is exaggerated. The irradiation angle θ increases in the order of the markers M1, M2, and M3, and the distance r between the markers differs depending on the distance from each camera ca.

  FIG. 11D is a diagram for explaining a method of calculating the rotation angle ω. When the optical axis of the camera ca is rotating from the reference axis (gravity direction), the image is inclined in the reverse rotation direction. The rotation angle ω can be calculated by calculating the inclination between the central axis and the reference axis of the plurality of markers M.

  FIG. 12 is a diagram corresponding to FIG. 10 and is a diagram illustrating the relationship between the two sets of markers M1 and M2 and the measurement position p1 of the camera ca. Consider a triangle with vertices M1, M2, and P1, respectively. The triangle consists of sides LA, LB, LC and their diagonals a, b, c.

  The distance between the sides LA and LB from the markers M1 and M2 can be obtained from the image taken by the camera ca. LC is a predetermined value because it is the distance between the marker M1 and the marker M2. If the lengths of the three sides of the triangle are known, the angle b and the angle a can be calculated, whereby the irradiation angles θ1 and θ2 can be calculated. For example, if LA, LB, and LC are 1200 mm, 1243 mm, and 150 mm, respectively, the angles a and b are 70.0 degrees and 103.3 degrees, respectively, so that the irradiation angles θ1 and θ2 are 13.3 degrees and 20. 0 degree.

  As described above, the irradiation position information can be calculated by variously processing the image obtained by capturing the marker M with the camera ca. In addition, there is a possibility that the patient P becomes a shadow and the marker M cannot be photographed from the camera ca. However, regarding this problem, two or more sets of the markers M are provided, or another member for attaching the markers M to the outside of the patient P is provided. May be. By moving the movable member 111 integrally with the movable member 111 so that the relative position between the separate member and the FPD 6 is maintained, or by providing a detection means for detecting the relative position with the FPD 6, the FPD 6 is detected from the position information of the marker M. Can be calculated. In addition, the marker M has a color or density different from that of the periphery, but is not limited thereto, and a member that emits light by an LED or the like may be used. Thereby, the pickup performance for the marker M is improved. Furthermore, it is preferable to use a member that emits infrared light by an infrared light emitting element or the like because further improvement in pickup performance is expected.

  Next, as a “second embodiment”, a means for acquiring a relative position in the imaging room 100 in the radiation irradiation apparatus 3, a means for acquiring a relative position in the imaging room 100 of the radiation irradiation apparatus 3, and radiation irradiation An irradiation position detection means using a triaxial inclination sensor gs that detects the inclination of the apparatus will be described. FIG. 13 is an explanatory diagram schematically illustrating the positional relationship between the radiation irradiation apparatus 3 and the FPD 6 in the second embodiment. P1 (x1, y1) is the coordinates of the radiation irradiation device 3, and P2 (x2, y2) is the coordinates of the reference point of the FPD 6. Both coordinates are coordinates having a predetermined position in the photographing room as the origin, and the calculation unit 324 can acquire information on both coordinates and calculate the distance SID from these relative positions. Further, since the inclination with respect to the horizontal plane can be detected by the output of the triaxial inclination sensor gs, the irradiation angle θ1 and the rotation angle ω can be calculated. In general, since the movement coordinates move in a two-axis plane, the example in FIG. 13 shows an example of the xy two-axis coordinates. However, the radiation irradiation apparatus 3 or the FPD 6 moves in three axes. If so, an embodiment in which the distance SID is calculated in the same manner with three-axis coordinates may be used.

  Next, as a “third embodiment”, an irradiation detection unit using the distance measuring sensor dws will be described. FIG. 14 is an explanatory diagram schematically showing the positional relationship between the radiation irradiation apparatus 3 and the FPD 6 in the third embodiment. In the third embodiment, the distance measurement sensor dws and the calculation unit 324 function as an irradiation position detection unit. Based on the output value of the distance measuring sensor dws, the distance (SID) from the detection surface S of the FPD 6 and the irradiation angle θ2 are calculated.

The height H (H = La + Lb) from the floor surface to the ceiling of the photographing room 100 is given as known information. Information on the height h from the floor of the FPD 6 is acquired from the movable unit 111. The distance sensor dws measures the distance Lb ′ between the radiation irradiation device 3 and the floor surface and the distance La ′ from the ceiling in the direction perpendicular to the X-ray optical axis. From these values, the irradiation angle θ2 and the distance SID are calculated as follows.
Irradiation angle θ2 = Acos ((La + Lb)) / (La ′ + Lb ′))
Distance SID = (Lb ′ × cos θ2−h) / sin θ2
In this embodiment, the rotation angle ω is 0. When ω is other than 0, ω can be obtained by directing the same mechanism toward the opposite wall surface.

  Next, as the “fourth embodiment”, the irradiation angle θ is measured by the light source light and the area sensor ps. Since the distance SID and the rotation angle ω are calculated by any one of the first to third embodiments, description thereof is omitted.

  FIG. 15 is an explanatory diagram schematically illustrating the positional relationship between the radiation irradiation apparatus 3 and the FPD 6 in the fourth embodiment. In the fourth embodiment shown in FIG. 15A, the light from the light source light provided in the FPD 6 or the movable portion 111 is irradiated to the radiation irradiation device 3 side, and the light is irradiated to the area sensor ps provided in the collimator device 32. Measure with As shown in the figure, a pinhole h is provided on the front side of the area sensor ps, and the irradiation angle θ can be measured by the position where the light that has passed through the pinhole h is received. In this embodiment, the moving direction of the irradiation unit 31 of the radiation irradiation apparatus 3 moves in the vertical direction (vertical direction or vice versa) instead of the rotation direction (swing), so that the light receiving surface of the area sensor ps is always in the vertical direction. It is parallel.

  FIG. 15B is a modification of the fourth embodiment. The light emitted from the light source light is split through the prism pr, and each color of the split light reaches the area sensor ps. In the area ps, the wavelength (color) of light is measured together with the light receiving position. By measuring the color, the relative angle with the light source light can be quickly grasped. In FIG. 15B, the light emitted from the light source light is white light, and the light is irradiated to the prism pr after being collimated by a lens (not shown) with the light source light.

[Control Flow in Other Embodiments]
FIG. 16 is a control flow diagram in long imaging performed by the radiographic image capturing system. In FIG. 16, the control common to FIG. Other configurations and control flows other than those in FIG. 16 are the same as those in FIGS. 1 to 6 and FIGS.

  In step S100, preparation for photographing is performed. At this time, the patient P stands on the imaging table in a positional relationship that matches the imaging conditions under the instruction of the imaging technician, and the imaging technician aligns the imaging affected area of the patient P with the imaging area in the long imaging. Then, a shooting position (shooting area) in a series of long shooting is set. The shooting position may be set for each image. By inputting the start position (for example, the upper side of the first image) and the end position (for example, the lower end of the third image), the interval is automatically set on the control BOX 4 side. You may make it set.

  In step S110, the camera moves to the n-th shooting position n (the shooting position 1 for the first shot). The movement is performed by moving the FPD 6 and the radiation irradiation apparatus 3 by the first position control unit 34 and the second position control unit 14 to move the irradiation position.

  In step S120, the irradiation position information n of the photographing position n is acquired by any of the irradiation position detection means described above. In step S121, the positional information acquired in step S120 and the imaging position setting information set in step S100 are compared to determine whether or not the radiation irradiation position is the correct imaging position. If not correct, the control from step S110 is repeated in order to perform fine adjustment.

  On the other hand, if it is a correct position (step S121: Yes), the process after step S13 will be performed. At this time, the photographing position information may be stored in the memory of the console 7 and used for the subsequent correction processing. Steps S110 and subsequent steps are repeated until a series of continuous shootings in the long shooting is completed (step S14).

  According to the present embodiment, it is possible to automatically take a long image using an existing radiographic image capturing system by adding a part of equipment.

3 Radiation irradiation equipment 4 Control BOX
6 Radiation detection means (FPD)
DESCRIPTION OF SYMBOLS 7 Console 31 Irradiation part 34 1st position control part 32 Collimator apparatus 324 Calculation part 326 Magnetic field sensor sensor 327 Irradiation field restriction part 329 Communication part ca Camera gs 3 axis inclination sensor dws Distance sensor 11 Imaging stand 11a Mounting port 111 Movable part 14 Second position control unit

Claims (5)

Radiation irradiating means for irradiating the subject with radiation;
Radiation detection means for acquiring image data by detecting radiation irradiated from the radiation irradiation means and transmitted through the subject; and
A collimator device comprising: an irradiation field limiting unit that limits an irradiation region of radiation irradiated from the radiation irradiation unit; and an irradiation field control unit that controls the irradiation field limiting unit;
First position control means for controlling a radiation irradiation position on a subject by controlling at least one of the radiation irradiation means and the collimator device;
A bookmarking device comprising: holding means for movably holding the radiation detection means; and second position control means for variably controlling the position of the radiation detection means held by the holding means relative to the subject;
The relative positional relationship between the radiation irradiating means and the radiation detecting means, or the relative positional relationship between the radiation irradiating means and the state of the collimator device detects the positional relation of the radiation irradiated by the radiation irradiating means with respect to the detection surface of the radiation detecting means. Irradiation position detection means;
A radiographic imaging system comprising:   The radiation image capturing system according to claim 1, wherein the irradiation position detection unit detects a radiation irradiation angle with respect to a detection surface of the radiation detection unit and a distance from the radiation irradiation unit. In the long shooting in which a series of shooting is performed on the subject in a plurality of shooting areas, and the image data acquired in the plurality of shooting areas is combined to generate long image data,
The radiographic image capturing system according to claim 2, wherein long image data is generated using detection data of the irradiation position detection unit of each image data.   4. The radiographic image according to claim 1, wherein the radiation detection unit held by the holding unit is moved by the second position control unit in accordance with an output of the irradiation position detection unit. 5. Shooting system. In the long shooting in which a series of shooting is performed on the subject in a plurality of shooting areas, and the image data acquired in the plurality of shooting areas is combined to generate long image data,
When adjusting the next photographing position with respect to one photographing position in the series of photographing, the radiation detecting means held by the holding means is moved by the second position control means based on the detection by the irradiation position detecting means. The radiographic image capturing system according to claim 4, wherein:

Images