JP5090247B2 - Radiation image capturing apparatus and radiation image capturing method - Google Patents

Description

  The present invention relates to a radiographic image capturing apparatus and a radiographic image capturing method, and more particularly to a radiation source that irradiates radiation toward a subject, provided on the opposite side of the subject, and is emitted from the radiation source to remove the subject. The present invention relates to a radiation image capturing apparatus and a radiation image capturing method for capturing a radiation image using an imaging unit that captures a radiation image of the subject by detecting transmitted radiation.

  In recent years, with the progress of an aging society, the number of patients with orthopedic diseases such as joints and spine has increased.

  X-rays are generally performed for the diagnosis of these orthopedic diseases, but in order to make an accurate diagnosis and treatment plan, each part of the joint space, etc., is taken on the acquired image. It is often necessary to know the exact dimensions.

  However, in normal X-ray imaging, X-ray detection is performed by detecting an X-ray emission source, a subject to be imaged, and an X-ray emitted from the source and transmitted through the subject. Depending on the positional relationship with the detector, the image obtained by the X-ray detector becomes an enlarged image with a larger enlargement ratio as the distance in the horizontal direction from the radiation source on the image receiving surface of the X-ray detector becomes longer.

  For this reason, when performing X-ray imaging that requires measurement of the dimensions of each part such as the joint space, generally the distance between the radiation source and the image receiving surface of the X-ray detector (hereinafter referred to as “SID”). (Also referred to as “Source Image Distance”), and the magnification ratio is often operated assuming a fixed value such as 1.1 times. However, in this case, restrictions on system use associated with fixing the SID, complications due to measurement and adjustment of the SID each time shooting occurs, and the difference in magnification in the captured image results in the above. It was extremely difficult to measure accurately.

  On the other hand, in X-ray imaging images in the orthopedic field, it is important to observe the fine structure of bone parts such as trabeculae, and the influence of scattered radiation generated when X-rays pass through the subject is small. It is desired.

  From the above, it is possible to easily and accurately correct the difference in magnification without strictly adjusting the SID, and to obtain a radiation image with less scattered radiation is particularly demanding in the orthopedic region. .

  As a technique that can be applied to meet these demands, Patent Document 1 also discloses a radiation source, a slot scanning mechanism, and a flat panel detector (hereinafter referred to as “FPD”). )) And using the data of the X-ray incident portion on the FPD corresponding to slot scanning, a system in which the influence of scattered radiation is reduced is disclosed.

  Patent Document 2 discloses a system that reduces the distortion of an image that occurs because the SID is different between the central portion and the peripheral portion of the FPD by making the radiation detector substantially spherical with the radiation source position as the center. It is disclosed.

Further, Patent Document 3 discloses a system that virtually obtains a spherical surface around a radiation source and performs correction by projecting image data detected by a radiation detector onto the virtual spherical surface to obtain volume data. Has been.
Japanese Patent Laid-Open No. 2006-142009 JP 2000-210274 A JP 2000-262507 A

  However, the technique disclosed in Patent Document 1 does not take into account the difference in magnification, and has a problem that the difference in magnification cannot be corrected.

  Further, the technique disclosed in the above-mentioned Patent Document 2 has a problem that it is necessary to adjust and fix the SID strictly, and it is necessary to make the radiation detector in a complicated shape, which takes time. was there.

  Furthermore, the technique disclosed in Patent Document 3 also has a problem in that it requires adjustment and fixing of the SID as in the technique disclosed in Patent Document 2, which is troublesome.

  The present invention has been made to solve the above problems, and a radiographic imaging apparatus and a radiographic image that can easily perform correction for a difference in magnification of radiographic images without performing strict adjustment of the SID. An object is to provide a photographing method.

  In order to achieve the above object, a radiographic imaging apparatus according to the present invention is provided on the opposite side of the subject from a radiation source that irradiates radiation toward the subject, and is emitted from the radiation source and transmitted through the subject. An imaging unit that captures a radiographic image of the subject by detecting the emitted radiation, and an elongated transmission part that is provided between the radiation source and the imaging unit and transmits the radiation. A scatter component removing plate that removes a scatter component of the radiation generated when passing through the subject, and the first direction parallel to the image receiving surface of the imaging means and perpendicular to the longitudinal direction of the transmission portion. A first distance between a radiation source and the transmission portion; a second distance between the subject and the image reception surface in a second direction perpendicular to the image reception surface; and the transmission portion in the second direction. And before Acquisition of a third distance between the image receiving surface and a fourth distance between the radiation source in the first direction and the radiation image transmitted through the transmission unit and imaged by the imaging means. And correction for correcting the position of the radiographic image in the first direction based on the first distance, the second distance, the third distance, and the fourth distance acquired by the acquisition means. Means.

  According to the radiographic image capturing apparatus of the present invention, the radiation emitted from the radiation source and transmitted through the subject by the imaging means provided on the opposite side of the subject from the radiation source that irradiates the subject with radiation. Is detected, a radiographic image of the subject is captured.

  Further, in the present invention, the scattering component removing plate provided between the radiation source and the imaging means and having a long transmission part that transmits the radiation generates the radiation when the radiation is transmitted through the subject. The scattered component of the radiation is removed.

  Here, in the present invention, a first distance between the radiation source and the transmission unit in a first direction parallel to the image receiving surface of the imaging unit and orthogonal to the longitudinal direction of the transmission unit, the image reception A second distance between the subject and the image receiving surface in a second direction perpendicular to the surface, a third distance between the transmitting portion and the image receiving surface in the second direction, and the first The acquisition unit acquires a fourth distance between the radiation source and the radiographic image captured by the imaging unit through the transmission unit in the direction of.

  And in this invention, based on the 1st distance acquired by the said acquisition means, the 2nd distance, the 3rd distance, and the 4th distance by the correction means, the said 1st direction of the said radiographic image Correction of the position with respect to is performed.

  As described above, in the radiographic image capturing apparatus of the present invention, the gap between the radiation source and the transmission unit in the first direction parallel to the image receiving surface of the imaging unit and perpendicular to the longitudinal direction of the transmission unit of the scattering component removing plate. A second distance between the subject and the image receiving surface in a second direction perpendicular to the image receiving surface, and a third distance between the transmitting portion and the image receiving surface in the second direction. And the position of the radiation image in the first direction based on the fourth distance between the radiation source in the first direction and the radiation image transmitted through the transmission unit and imaged by the imaging unit. Therefore, it is possible to easily correct the difference in the enlargement ratio of the radiation image without strict adjustment of the SID.

  The correction means sets the first distance as b, the second distance as d, the third distance as e, and the fourth distance as c, according to the following formula: The correction may be performed by calculating a corrected fifth distance a between the radiation source and the radiation image in the first direction, and positioning the radiation image at the calculated distance a. .

また、前記第１の距離、前記第３の距離、及び前記第４の距離に基づいて、前記第２の方向における前記放射線源と前記撮像手段の受像面との間の第６の距離を導出する導出手段をさらに備え、前記補正手段は、前記導出手段によって導出された第６の距離に基づいて、前記放射線画像の前記受像面に平行で、かつ前記透過部の長手方向である第３の方向に対する位置の補正をさらに行ってもよい。

A sixth distance between the radiation source and the image receiving surface of the imaging unit in the second direction is derived based on the first distance, the third distance, and the fourth distance. Derivation means, and the correction means is based on the sixth distance derived by the derivation means, and is parallel to the image receiving surface of the radiation image and in the longitudinal direction of the transmission part. You may further correct | amend the position with respect to a direction.

  The derivation means calculates the sixth distance f by the following arithmetic expression, where b is the first distance, e is the third distance, and c is the fourth distance. Derived,

前記補正手段は、前記第２の距離をｄとし、前記放射線源と前記放射線画像との間の前記第３の方向に対する第７の距離をｙとして、次の演算式により、前記放射線源と前記放射線画像との間の前記第３の方向に対する補正後の第８の距離ｘを算出し、算出した距離ｘの位置に前記放射線画像を位置させることにより前記放射線画像の前記第３の方向に対する位置の補正を行ってもよい。

The correction means sets the second distance to d, and sets the seventh distance between the radiation source and the radiation image to the third direction as y. The corrected eighth distance x with respect to the third direction with respect to the radiation image is calculated, and the position of the radiation image in the third direction is determined by positioning the radiation image at the calculated distance x. May be corrected.

また、前記被写体の前記第２の方向に対する中心位置を取得する第２の取得手段をさらに備え、前記取得手段は、前記被写体の前記第２の方向に対する位置として前記第２の取得手段によって取得された中心位置を適用してもよい。

The image acquisition apparatus further includes second acquisition means for acquiring a center position of the subject in the second direction, and the acquisition means is acquired by the second acquisition means as a position of the subject in the second direction. A central position may be applied.

  Further, the scattering component removing plate may be a slit plate in which the transmission part is a slit, and the transmission part has an absorption rate of the radiation less than a predetermined rate, and the transmission part and the radiation It may be a grid plate provided alternately with absorbing portions whose absorption rate is equal to or higher than the predetermined rate.

  In addition, the storage device may further include a storage unit that stores the first distance, the second distance, and the third distance in advance, and the acquisition unit reads the first distance, The second distance and the third distance may be acquired. The storage means includes a RAM (Random Access Memory), an EEPROM (Electrically Erasable and Programmable Read Only Memory), a semiconductor storage element such as a flash EEPROM (Flash EEPROM), an SD memory card (registered trademark), a flexible disk, etc. A portable recording medium, a fixed recording medium such as a hard disk, or an external storage device provided in a server computer connected to a network.

  Furthermore, a moving unit that moves the scattering component removing plate in the first direction when the radiographic image is captured by the imaging unit may be further provided.

  On the other hand, in order to achieve the above object, the radiographic image capturing method of the present invention emits radiation from the radiation source by an imaging means provided on the opposite side of the radiation source that irradiates the radiation toward the subject. The radiation is transmitted through the subject by a scattering component removing plate having a long transmission part that transmits the radiation and is transmitted between the radiation source and the imaging unit. An imaging step of capturing a radiation image of the subject by detecting the radiation from which the scattered component of the radiation generated at the time is removed, and parallel to the image receiving surface of the imaging unit and in the longitudinal direction of the transmission unit A first distance between the radiation source and the transmission unit in a first direction orthogonal to each other; a second distance between the subject and the image receiving surface in a second direction perpendicular to the image receiving surface; A third distance between the transmission part and the image receiving surface in the second direction, and a radiation image transmitted by the radiation source and the transmission part in the first direction and imaged by the imaging means An acquisition step of acquiring a fourth distance between and the first distance, the second distance, the third distance, and the fourth distance acquired by the acquisition step; And a correction step of correcting the position with respect to the first direction.

  Therefore, since the radiographic image capturing method of the present invention operates in the same manner as the radiographic image capturing apparatus of the present invention, as in the radiographic image capturing apparatus, the radiographic image enlargement ratio can be adjusted without strict adjustment of the SID. Correction for the difference can be easily performed.

  As described above, according to the present invention, there is an excellent effect that it is possible to easily perform correction for the difference in the enlargement ratio of the radiation image without strictly adjusting the SID.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a case where the present invention is applied to a radiographic image capturing apparatus that captures a radiographic image using X-rays will be described.

  FIG. 1 shows a schematic configuration of a radiation image capturing apparatus 10 according to the present embodiment.

  As shown in the figure, the radiographic image capturing apparatus 10 according to the present embodiment includes a tube 14 that emits X-rays 15 to a subject 12, a photographing table 18 on which the subject 12 is placed, and a subject 12 An X-ray detection element (FPD) 20 which is provided so that the image receiving surface faces the opposite side of the tube 14 and directly converts X-rays received on the image receiving surface into digital data; A slit plate 16 provided between the subject 12 and the X-ray scattering component generated when the X-rays pass through the subject 12; It is equipped with.

  As shown in FIG. 2, the slit plate 16 according to the present embodiment is provided with one or more kinds of materials (for example, lead, steel, It is formed by a plate-like member 16b constituted by a combination of tungsten and the like.

  In radiographic imaging device 10 according to the present exemplary embodiment, when radiographic imaging is performed, X-rays 15 are emitted from tube 14 toward slit plate 16 as shown in FIG. Is moved in a direction (hereinafter referred to as “slit scanning direction”) that is parallel to the image receiving surface of the X-ray detection element 20 and perpendicular to the longitudinal direction of the slit 16a (hereinafter referred to as “slit width direction”). The subject 12 is scanned and a radiographic image is taken by the X-ray detection element 20. For this reason, in the radiographic imaging device 10, the tube 14 is rotated within a predetermined angle range so that the X-ray 15 is irradiated onto the slit plate 16, and the slit plate 16 is moved in the slit scanning direction. A mechanism that does not (hereinafter referred to as “slit scanning mechanism”) is provided.

  As described above, the slit plate 16 serves to minimize the irradiation region of the X-ray subject 12 in addition to the role of removing the X-ray scattering component. The X-ray radiated from the tube 14 has a predetermined size so as not to protrude from the outer peripheral portion.

  The X-ray 15 emitted from the tube 14 passes through the slit 16 a of the slit plate 16 that is moved in the slit scanning direction, further passes through the subject 12 and reaches the X-ray detection element 20. The X-ray detection element 20 is provided with a plurality of sensor units having sensitivity to X-rays on an image receiving surface in a two-dimensional manner, and captures a radiographic image received on the image receiving surface.

  FIG. 3 shows an example of a detailed configuration of the X-ray detection element 20 according to the present embodiment.

  As shown in the figure, the X-ray detection element 20 has sensitivity to X-rays, and stores a sensor unit 22 that accumulates charges according to the dose of irradiated X-rays, and the sensor unit 22 stores the charges. A plurality of pixels each including a TFT (Thin film transistor) switch 24 for reading out electric charges is provided in a two-dimensional manner.

  Further, the X-ray detection element 20 includes a plurality of scanning wirings 26 for turning on / off the TFT switch 24 and a plurality of signals for reading out electric charges accumulated in the sensor unit 22. The wiring 28 is provided so as to cross each other.

  An electric signal corresponding to the amount of electric charge accumulated in the sensor unit 22 flows through each signal line 28 when any TFT switch 24 connected to the signal line 28 is turned on. Each signal wiring 28 is connected to a signal detection circuit 30 for detecting an electric signal flowing out to each signal wiring 28, and each scanning wiring 26 is used to turn on / off the TFT switch 24 in each scanning wiring 26. A scan signal control device 32 for outputting the control signal is connected.

  The signal detection circuit 30 incorporates an amplification circuit for amplifying an input electric signal for each signal wiring 28. In the signal detection circuit 30, the electric signal input from each signal wiring 28 is amplified and detected by the amplification circuit, so that the information (pixel value) of each pixel constituting the image is accumulated in each sensor unit 22. Detect the amount of charge.

  The signal detection circuit 30 and the scan signal control device 32 perform predetermined processing on the electrical signal detected by the signal detection circuit 30 and output a control signal indicating the signal detection timing to the signal detection circuit 30. A signal processing device 34 is connected to the scan signal control device 32 for outputting a control signal indicating the output timing of the scan signal.

  A part of the X-ray 15 emitted from the tube 14 is scattered when passing through the subject 12, but the range of the X-ray 15 incident on the subject 12 by the slit 16a of the slit plate 16 is the minimum necessary for imaging. As a result, a clear radiation image with a small amount of scattered X-ray components is recorded on the X-ray detection element 20. In addition, since the range of X-rays incident on the subject 12 is limited to the minimum range necessary for imaging, the amount of X-ray exposure by the subject 12 can be minimized.

  In the radiographic imaging apparatus 10 according to the present exemplary embodiment, the slit plate 16 and the X-ray detection element 20 are arranged so that the longitudinal direction of the slit 16a is the laying direction of the scanning wiring 26.

  FIG. 4 shows a configuration of the control unit 50 that controls the operation of the radiographic imaging apparatus 10 according to the present exemplary embodiment.

  As shown in the figure, the control unit 50 includes a CPU (Central Processing Unit) 52 that controls the operation of the entire radiographic imaging apparatus 10 and a RAM (Random Access) used as a work area when the CPU 52 executes various processing programs. Memory) 54, ROM (Read Only Memory) 56 in which various control programs, various processing programs, various parameters and the like are stored in advance, HDD (Hard Disk Drive) 58 in which various information is stored, and signal processing device 34 By controlling the detection element control unit 60 that controls the imaging operation by the X-ray detection element 20 by controlling the X-ray radiation direction of the tube 14 and the power supply to the tube 14, The radiation source control unit 62 that controls the X-ray emission from the tube 14 and the operation panel 64 that has a display unit and receives an instruction operation are controlled. An operation panel control unit 66, and a.

  The CPU 52, RAM 54, ROM 56, HDD 58, detection element control unit 60, radiation source control unit 62, and operation panel control unit 66 are connected to each other via a system bus BUS.

  Therefore, the CPU 52 accesses the RAM 54, ROM 56, and HDD 58, controls the imaging operation of the X-ray detection element 20 via the detection element controller 60, and X-rays from the tube 14 via the radiation source controller 62. And control of the operation panel 64 via the operation panel control unit 66 can be performed.

  In the radiographic imaging apparatus 10 according to the present exemplary embodiment, as shown in FIG. 5 as an example, the first is parallel to the image receiving surface of the X-ray detection element 20 and orthogonal to the longitudinal direction of the slit 16a of the slit plate 16. A first distance b between the tube 14 and the slit 16a in the direction of, a second distance d between the subject 12 and the image receiving surface in a second direction perpendicular to the image receiving surface, the second A third distance e between the slit 16a in the direction and the image receiving surface, and a radiation image transmitted by the X-ray detection element 20 through the tube 14 and the slit 16a in the first direction. Based on the fourth distance c, the position of the radiation image is corrected with respect to the first direction.

  Here, in the radiographic imaging apparatus 10 according to the present exemplary embodiment, the following (1) is performed using the first distance b, the second distance d, the third distance e, and the fourth distance c. The corrected fifth distance a in the first direction between the tube 14 and the radiographic image is calculated by the equation, and the correction is performed by positioning the radiographic image at the calculated distance a. Do.

また、本実施の形態に係る放射線画像撮影装置１０では、上記第１の距離ｂ、第３の距離ｅ、及び第４の距離ｃに基づいて、上記第２の方向における管球１４とＸ線検出素子２０の受像面との間の第６の距離ｆを導出し、導出した第６の距離ｆに基づいて、上記放射線画像の上記受像面に平行で、かつスリット１６ａの長手方向である第３の方向に対する位置の補正をさらに行う。

In the radiographic image capturing apparatus 10 according to the present embodiment, the tube 14 and the X-ray in the second direction are based on the first distance b, the third distance e, and the fourth distance c. A sixth distance f between the detection element 20 and the image receiving surface is derived. Based on the derived sixth distance f, the sixth distance f is parallel to the image receiving surface of the radiation image and is the longitudinal direction of the slit 16a. Further correction of the position in the direction 3 is performed.

  Here, in the radiographic imaging device 10 according to the present exemplary embodiment, the sixth distance f is calculated by the following equation (2).

そして、放射線画像撮影装置１０では、管球１４と上記放射線画像との間の上記第３の方向に対する第７の距離ｙを用いて、次の（３）式により、管球１４と上記放射線画像との間の上記第３の方向に対する補正後の第８の距離ｘを算出し、算出した距離ｘの位置に上記放射線画像を位置させることにより当該放射線画像の上記第３の方向に対する位置の補正を行う。

And in the radiographic imaging device 10, using the seventh distance y with respect to the third direction between the tube 14 and the radiographic image, the tube 14 and the radiographic image are expressed by the following equation (3). The corrected eighth distance x with respect to the third direction is calculated, and the position of the radiographic image in the third direction is corrected by positioning the radiographic image at the calculated distance x I do.

このため、ＲＯＭ５６の所定領域には、放射線画像撮影装置１０における距離ｂ及び距離ｅと、撮影テーブル１８の上面とＸ線検出素子２０の受像面との間の上記第２の方向に対する第９の距離ｇの各距離を示す値が予め記憶されている。

Therefore, the predetermined area of the ROM 56 includes a distance b and a distance e in the radiographic image capturing apparatus 10 and a ninth direction with respect to the second direction between the upper surface of the imaging table 18 and the image receiving surface of the X-ray detection element 20. A value indicating each distance of the distance g is stored in advance.

  In the radiographic image capturing apparatus 10 according to the present embodiment, in order to accurately correct the radiographic image, in order to apply the center position of the subject 12 in the second direction according to the physique of the subject 12, The tenth distance h with respect to the second direction from the upper surface of the imaging table 18 to the center position is specified, and the tenth distance h is added to the ninth distance g to thereby add the second distance d. Is derived.

  In the radiographic image capturing apparatus 10 according to the present exemplary embodiment, the subject 12 is divided into four types of adult men, children's men, adult women, and children's women, and the tenth distance h is set for each category. Applicable. For this reason, information indicating the tenth distance h for each of these sections is also stored in the predetermined area of the ROM 56 in advance.

  Note that the fourth distance c and the seventh distance y are distances from the tube 14 of the radiographic image to be corrected that is transmitted by the X-ray detection element 20 through the slit 16a. It can be uniquely identified from the position of the sensor unit 22 of the X-ray detection element 20 that has captured the radiation image.

  Next, the operation of the radiographic image capturing apparatus 10 according to the present embodiment will be described.

  When radiographing is performed, the laboratory technician lays the subject 12 on the radiographing table 18 and performs a predetermined instruction operation for instructing radiographing on the radiographic image capturing apparatus 10 via the operation panel 64. .

  The radiographic image capturing apparatus 10 executes an image capturing process when a predetermined instruction operation for instructing capturing is performed.

  Hereinafter, with reference to FIG. 6, the operation of the radiographic image capturing apparatus 10 when the image capturing process is executed will be described. FIG. 6 is a flowchart showing the flow of processing of an image capturing processing program executed by the CPU 52 of the radiation image capturing apparatus 10 when executing the image capturing processing, and the program is stored in a predetermined area of the ROM 56 in advance. Has been.

  In step 100 in the figure, the slit plate 16 is moved to a predetermined home position as an initial position for photographing, and the rotation angle of the tube 14 is changed to the slit plate 16 moved to the home position. An initial setting is made to set a predetermined angle as an angle at which X-rays are emitted toward.

  In the next step 102, control is performed so that a predetermined subject information input screen is displayed on the display unit provided on the operation panel 64. In the next step 104, input of predetermined information via the operation panel 64 is awaited. I do.

  FIG. 7 shows an example of a display state of the subject information input screen displayed on the display unit 64a of the operation panel 64 by the processing in step 102.

  As shown in the figure, on the subject information input screen according to the present embodiment, a message prompting the user to specify information related to the person to be photographed (subject 12) and information of a predetermined type as information that can be specified (here) Then, four types of information “adult”, “child”, “male”, and “female” are displayed. When the subject information input screen shown in the figure is displayed by the display unit 64a of the operation panel 64, the inspection engineer specifies information corresponding to the subject 12, and then the end displayed at the bottom of the screen. Specify a button. Accordingly, step 104 is affirmative and the process proceeds to step 106.

  In step 106, the tenth distance h corresponding to the information specified on the subject information input screen is read from the ROM 56 to identify the tenth distance h. In the next step 108, the predetermined distance h is determined. After starting the rotation of the tube 14 and the movement of the slit plate 16 in the slit scanning direction, in the next step 110, the tube 14 is started to emit X-rays, and in the next step 112, An imaging operation is started with respect to the X-ray detection element 20. As a result, each sensor unit 22 of the X-ray detection element 20 accumulates charges according to the dose of X-rays irradiated through the slit 16a of the slit plate 16.

  In the next step 114, radiation corresponding to the number of lines (here, 5 lines) determined in advance to be taken by the X-ray detection element 20 in accordance with the width of the slit 16a in the first direction. An image (hereinafter referred to as “read target image”) is read from the X-ray detection element 20.

  Here, the CPU 52 controls the signal processing device 34 via the detection element control unit 60, and sequentially turns on each scanning wiring 26 corresponding to the target image from the scanning signal control device 32 line by line. 20V), and the TFT switches 24 connected to the scanning wirings 26 are turned on one line at a time. As a result, an electric signal corresponding to the amount of electric charge accumulated in each sensor unit 22 flows out to each signal line 28 line by line. The signal detection circuit 30 detects the amount of charge accumulated in each sensor unit 22 based on the electrical signal flowing out to the signal wiring 28 as the pixel value of each pixel constituting the image. Thereby, image information indicating the read target image can be obtained.

  In the next step 116, the image information obtained by the processing in the above step 114 is stored in the RAM 54, and in the next step 118, it is determined whether or not the image information in the entire photographing target region has been obtained. Thus, it is determined whether or not shooting of the shooting target area has been completed, and if a negative determination is made, the process returns to step 114, while when an affirmative determination is made, the process proceeds to step 120. Through the above processing, image information indicating a radiographic image corresponding to the entire region to be imaged is stored in the RAM 54.

  In step 120, the imaging operation is stopped for the X-ray detection element 20, and in the next step 122, the X-ray emission is stopped for the tube 14. 14 and the movement of the slit plate 16 in the slit scanning direction are stopped.

  In the next step 126, image information (hereinafter referred to as “processing target image information”) indicating the radiation image corresponding to the entire imaging target region is read from the RAM 54, and in the next step 128, the distance b, the distance e, and A value indicating each distance of the distance g is read from the ROM 56.

  In the next step 130, the processing target image information is corrected as follows.

  First, the second distance d is calculated by adding the tenth distance h specified by the processing of step 106 to the distance g, and the fourth distance c is specified for each line of the processing target image information. To do.

  Next, for each line of the processing target image information, the calculated distance d and distance c, and the distance b and distance e read out by the processing of step 128 are substituted into the above equation (1) to obtain the distance a. By calculating and positioning the corresponding radiographic image at the calculated distance a, the radiographic image is corrected in the first direction.

  Next, the distance f is calculated by substituting the distance b, the distance e, and the distance c into the equation (2), and the distance d, the distance f, and the distance y are calculated for each pixel of the processing target image information. By substituting into the equation (3), the distance x is calculated, and the corresponding radiographic image is positioned at the calculated distance x, thereby correcting the position of the radiographic image in the third direction.

  When the process of step 130 is finished, the image photographing process program is finished.

  As described in detail above, according to the present embodiment, the light is transmitted through the scattering component removing plate (here, the slit plate 16) parallel to the image receiving surface of the imaging means (here, the X-ray detection element 20). A first distance (here, distance b) between the radiation source (here, the tube 14) and the transmission part in a first direction orthogonal to the longitudinal direction of the portion (here, slit 16a), A second distance (here, distance d) between the subject and the image receiving surface in a second direction perpendicular to the image receiving surface, and a third distance between the transmitting portion and the image receiving surface in the second direction. And a fourth distance (here, distance c) between the radiation source in the first direction and the radiographic image picked up by the imaging means through the transmission unit in the first direction. Based on the position of the radiation image relative to the first direction. Since performed without performing strict adjustment of SID, the correction for the difference in the magnification of the radiation image can be easily performed.

  Further, according to the present embodiment, the correction is performed by calculating the distance a by the equation (1) and positioning the radiation image at the position of the distance a, so that the correction can be performed more easily. Can do.

  Further, according to the present embodiment, based on the first distance, the third distance, and the fourth distance, the radiation source in the second direction and the image receiving surface of the imaging unit And a sixth distance (here, distance f) between them is derived, and based on the derived sixth distance, the third distance that is parallel to the image receiving surface of the radiographic image and that is the longitudinal direction of the transmission portion Since the correction of the position with respect to the direction is further performed, the correction can be easily performed.

  Further, according to the present embodiment, after calculating the distance f by the expression (2), the distance x is calculated by the expression (3), and the radiation image is positioned at the position of the calculated distance x. Since the position of the image with respect to the third direction is corrected, the correction can be performed more easily.

  According to the present embodiment, the center position of the subject in the second direction is acquired, and the acquired center position is applied as the position of the subject in the second direction. The correction can be performed with high accuracy.

  In addition, according to the present embodiment, a slit plate in which the transmission part is a slit is applied as the scattering component removal plate, so that the present invention can be applied to an apparatus using the slit plate. .

  Further, according to the present embodiment, the first distance, the second distance, and the third distance are stored in advance by the storage means (here, the ROM 56) and read out from the storage means. Since the first distance, the second distance, and the third distance are acquired, the distances can be easily acquired.

  Furthermore, according to the present embodiment, since the scattering component removing plate is moved in the first direction when the radiographic image is captured by the imaging unit, the difference in the enlargement ratio of the two-dimensional planar radiographic image Can be easily corrected.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the above-described embodiment without departing from the gist of the invention, and embodiments to which such modifications or improvements are added are also included in the technical scope of the present invention.

  The above embodiments do not limit the invention according to the claims (claims), and all the combinations of features described in the embodiments are essential for the solution means of the invention. Is not limited. The embodiments described above include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. Even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, as long as an effect is obtained, a configuration from which these some constituent requirements are deleted can be extracted as an invention.

  For example, in the above-described embodiment, the case where the distance a, the distance f, and the distance x are derived by calculating each of the arithmetic expressions (1) to (3) has been described, but the present invention is not limited thereto. For example, table information (conversion information) in which the substituted values in the equations (1) to (3) are used as input values and the calculated values according to the corresponding arithmetic expressions are used as output values is stored in the ROM 56, HDD 58, etc. The distance a, the distance f, and the distance x may be derived using the table information stored in advance by the means. In this case, although the storage capacity for storing the table information is required, it is possible to reduce the calculation time and calculation load when using the calculation formula.

  In the above embodiment, the case where the tube 14 is rotated while being synchronized with the movement of the slit plate 16 when taking a radiographic image has been described. However, the present invention is not limited to this. Alternatively, it is also possible to take an image while moving only the slit plate 16 in a state where X-rays in a range that can cover the entire area of the subject 12 are emitted from the tube 14 without rotating the tube 14. In this case, in order to prevent unnecessary irradiation of the subject 12 with X-rays, it is necessary to make the slit plate 16 larger than that according to the above embodiment, but it is necessary to rotate the tube 14. Therefore, the mechanism for the rotation can be reduced. As a result, the cost can be reduced as compared with the above embodiment.

  In the above embodiment, the case where the present invention is applied to the radiographic image capturing apparatus 10 using the FPD has been described. However, the present invention is not limited to this, and for example, an imaging plate is used. You may apply this invention to a radiographic imaging apparatus. In this case as well, the same effects as in the above embodiment can be obtained.

  Moreover, although the case where this invention was applied to the radiographic imaging apparatus 10 which detects the radiographic image by X-ray as a radiation was demonstrated in the said embodiment, this invention is not limited to this, For example, a radiation Other radiations such as gamma rays, ultraviolet rays, and infrared rays may be used. In this case as well, the same effects as in the above embodiment can be obtained.

  In the above embodiment, the case where the present invention is applied to the radiographic image capturing apparatus 10 that performs radiography in a supine position has been described. However, the present invention is not limited to this, and a standing position, a sitting position, and the like. It can also be set as the form applied to the radiographic imaging apparatus which performs radiography by other body positions. In this case as well, the same effects as in the above embodiment can be obtained.

  In the above embodiment, the subject is classified into four types, that is, an adult man, a child man, an adult woman, and a child woman, and the tenth distance h determined in advance for each category is applied. However, the present invention is not limited to this, and in addition to these different items of sex, adults and children, for example, other items such as weight, age, height, etc., alone or in combination Alternatively, the tenth distance h may be applied to each section. In this case as well, the same effects as in the above embodiment can be obtained.

  In the above embodiment, the case where the tenth distance h is set according to the type of the subject 12 has been described. However, the present invention is not limited to this, and the tenth distance h is an average of people. By applying a typical value, the second distance d can be applied as a fixed value. In this case as well, the same effects as in the above embodiment can be obtained.

  In the above embodiment, the case where image information is read from the X-ray detection element 20 using a plurality of lines as one read unit has been described. However, the present invention is not limited to this, and image information is read line by line. Alternatively, the entire image information may be read at a time after the photographing of the entire photographing target region is completed. In these cases, the same effects as in the above embodiment can be obtained.

  Moreover, although the case where the slit plate 16 is applied as the scattering component removing plate of the present invention has been described in the above embodiment, the present invention is not limited to this. For example, the transmission portion has an absorption rate of radiation. The grid plate in which the transmission portion and the absorption portion having the radiation absorption rate equal to or higher than the predetermined rate are alternately applied as the scattering component removal plate of the present invention. You can also.

  FIG. 8 shows an example of the configuration of the grid plate 40 in this case.

  As shown in the figure, the grid plate 40 has an absorption part 42 mainly composed of lead that absorbs X-rays and a transmission part 44 mainly composed of aluminum that transmits X-rays each having a predetermined width. In this case, the strips are stretched in one direction to form strips, and the absorbing portions 42 are alternately provided at a predetermined pitch in a direction orthogonal to the one direction. When the grid plate 40 is applied to the above-described embodiment, the grid plate 40 is arranged so that the one direction in which the absorption unit 42 and the transmission unit 44 are extended is the scanning wiring direction of the X-ray detection element 20.

  Further, as shown in FIG. 9, in the absorption unit 42, the X-ray 15 emitted from the tube 14 passes through the transmission unit 44 between the absorption units 42 and enters the X-ray detection element 20 straightly. Thus, it is formed with a slight inclination according to the position.

  Therefore, as shown in the figure, the X-ray 15 (solid line in the figure) emitted from the tube 14 and transmitted straight through the subject 12 is absorbed by the absorber 42 according to the irradiation position of the grid plate 40. On the other hand, the X-ray detection element 20 is irradiated through the transmission part 44 while being blocked.

  On the other hand, X-rays 15 emitted from the tube 14 are partially scattered when passing through the subject 12. Scattered X-rays 15a scattered within the subject 12 (the one-dot chain line in the figure) are incident obliquely with respect to the inclination of the absorber 42, and are absorbed by the absorber 42 inside the grid plate 40, or of the grid plate 40. Since it is reflected by the surface, the X-ray detection element 20 is not irradiated. Therefore, a clear radiation image with little irradiation of scattered X-rays 15a is recorded on the X-ray detection element 20.

  In addition, it cannot be overemphasized that you may use together the slit board 16 applied in the said embodiment with respect to this form. In these cases, the same effects as in the above embodiment can be obtained.

  In addition, the configuration of the radiographic imaging apparatus 10 described in the above embodiment (see FIGS. 1 to 4) is merely an example, and a new member or an unnecessary member is provided without departing from the gist of the present invention. Needless to say, can be deleted, or the positional relationship of each member can be changed.

  The processing flow of the image shooting processing program described in the above embodiment (see FIG. 6) is also an example, and new steps are added or unnecessary steps are made within the scope not departing from the gist of the present invention. Needless to say, it can be deleted or the processing order can be changed.

  Furthermore, the arithmetic expressions (1) to (3) described in the above embodiment are also examples, and new parameters are added or unnecessary parameters are deleted without departing from the gist of the present invention. Needless to say, you can.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the whole structure of the radiographic imaging apparatus which concerns on embodiment, (a) is side sectional drawing which made the slit scanning direction the horizontal direction, (b) is side sectional drawing which made the slit width direction horizontal. It is. It is a top view which shows the detailed structure of the slit board which concerns on embodiment. It is a block diagram which shows the detailed structure of the X-ray detection element which concerns on embodiment. It is a block diagram which shows the electrical principal part structure of the control part which concerns on embodiment. It is a figure which shows the various parameters applied with the radiographic imaging apparatus which concerns on embodiment. It is a flowchart which shows the flow of a process of the image shooting processing program which concerns on embodiment. It is the schematic which shows an example of the display state of the to-be-photographed object information input screen which concerns on embodiment. It is a top view which shows the structure of the grid board which concerns on the other example of embodiment. It is a figure which shows the example of a structure of the radiographic imaging apparatus at the time of applying the grid plate shown in FIG. 8, and the irradiation state of the X-ray radiated | emitted from the tube.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Radiographic imaging device 12 Subject 14 Tube 16 Slit plate (scattering component removal plate)
16a Slit (Transmission part)
20 X-ray detection element (imaging means)
22 Sensor unit 40 Grid plate (scattering component removing plate)
42 Absorber 44 Transmitter 52 CPU (Acquisition means, correction means, derivation means, second acquisition means, movement means)
56 ROM (storage means)
58 HDD

Claims (10)

An imaging unit that is provided on the opposite side of the subject from the radiation source that emits radiation toward the subject, and that captures a radiation image of the subject by detecting the radiation emitted from the radiation source and transmitted through the subject When,
Scattering that is provided between the radiation source and the imaging means and has a long transmissive part that transmits the radiation, and removes the scattered component of the radiation generated when the radiation passes through the subject. A component removal plate;
A first distance between the radiation source and the transmission portion in a first direction parallel to the image receiving surface of the imaging means and perpendicular to the longitudinal direction of the transmission portion; a second distance perpendicular to the image reception surface; A second distance between the subject and the image receiving surface in a direction, a third distance between the transmission portion and the image receiving surface in the second direction, and the radiation source in the first direction. An acquisition means for acquiring a fourth distance between the radiation image transmitted through the transmission section and captured by the imaging means;
Correction means for correcting the position of the radiation image in the first direction based on the first distance, the second distance, the third distance, and the fourth distance acquired by the acquisition means;
A radiographic imaging apparatus comprising: The correcting means sets the first distance as b, the second distance as d, the third distance as e, and the fourth distance as c. The fifth distance a after correction in the first direction between the first image and the radiographic image is calculated, and the correction is performed by positioning the radiographic image at the calculated distance a.

The radiographic imaging apparatus according to claim 1. Derivation for deriving a sixth distance between the radiation source and the image receiving surface of the imaging means in the second direction based on the first distance, the third distance, and the fourth distance. Further comprising means,
The correction means further corrects the position of the radiographic image in a third direction that is parallel to the image receiving surface and that is the longitudinal direction of the transmission part, based on the sixth distance derived by the derivation means. The radiographic imaging device according to claim 1 or 2. The deriving means derives the first distance by b, the third distance by e, and the fourth distance by c by calculating the sixth distance f by the following arithmetic expression. ,

The correction means sets the second distance to d, and sets the seventh distance between the radiation source and the radiation image to the third direction as y. The corrected eighth distance x with respect to the third direction with respect to the radiation image is calculated, and the position of the radiation image in the third direction is determined by positioning the radiation image at the calculated distance x. To correct

The radiographic imaging apparatus according to claim 3. A second acquisition means for acquiring a center position of the subject in the second direction;
The radiographic imaging apparatus according to claim 1, wherein the acquisition unit applies a center position acquired by the second acquisition unit as a position of the subject with respect to the second direction. The radiographic image capturing apparatus according to claim 1, wherein the scattering component removal plate is a slit plate in which the transmission portion is a slit. In the scattering component removing plate, the transmission part has an absorption rate of the radiation less than a predetermined rate, and the transmission unit and an absorption unit having an absorption rate of the radiation equal to or higher than the predetermined rate are alternately provided. The radiographic imaging device according to any one of claims 1 to 5, wherein the radiographic imaging device is a grid plate. A storage means for storing the first distance, the second distance, and the third distance in advance;
The radiographic imaging according to any one of claims 1 to 7, wherein the acquisition unit acquires the first distance, the second distance, and the third distance by reading from the storage unit. apparatus. The radiographic imaging apparatus according to claim 1, further comprising a moving unit that moves the scattering component removing plate in the first direction when the radiographic image is captured by the imaging unit. . An imaging unit provided on the opposite side of the subject from the radiation source that irradiates radiation toward the subject is emitted from the radiation source and transmitted through the subject, and between the radiation source and the imaging unit. Detecting radiation from which the scattered component of the radiation generated when the radiation is transmitted through the subject is removed by a scattering component removing plate having a long transmission part that transmits the radiation. An imaging step of capturing a radiographic image of the subject,
A first distance between the radiation source and the transmission portion in a first direction parallel to the image receiving surface of the imaging means and perpendicular to the longitudinal direction of the transmission portion; a second distance perpendicular to the image reception surface; A second distance between the subject and the image receiving surface in a direction, a third distance between the transmission portion and the image receiving surface in the second direction, and the radiation source in the first direction. An acquisition step of acquiring a fourth distance between the radiation image transmitted through the transmission unit and captured by the imaging unit;
A correction step of correcting the position of the radiation image in the first direction based on the first distance, the second distance, the third distance, and the fourth distance acquired by the acquisition step;
A radiographic imaging method comprising:

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