JP2011194214A - Radiographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce discontinuity of the motion of an object on a moving image if the fast moving object is present within a range of radiation detection while suppressing the radiation exposure of a subject.SOLUTION: In radiographing and displaying a radiation moving image in the IVR by inserting a catheter (a guide wire) into a blood vessel of a patient, an exposure condition for normal time in which priority is given to the reduction of radiation exposure is set initially (200). When a pulsating internal organ such as the heart or lung enters the range of the moving image (214 is positive), an exposure condition with a longer radiation irradiation time t than in normal time is set (228), or an exposure condition with a shorter radiation irradiation cycle T than in normal time is set (234). In this way, the discontinuity of the motion of the pulsating internal organ on the moving image can be reduced.

Description

  The present invention relates to a radiographic image capturing apparatus, and more particularly to a radiographic image capturing apparatus that detects radiation at a timing synchronized with intermittent radiation and simultaneously displays the detection result as a moving image.

  In recent years, a catheter with various instruments attached to the tip is inserted into the patient's body, and the tip of the catheter reaches the lesion while observing the state of the patient's body in real time using the radiological image displayed on the monitor. , IVR (Interventional Radiology) that treats a catheter by operating it outside the body is rapidly spreading. However, the opportunity to take and display a radiological moving image in the medical field is increasing, including this IVR. .

  With respect to radiographic image capturing, Patent Document 1 describes the magnitude of movement of a subject between frames by comparing subject images between consecutive frames in order to prevent blurring from occurring at an edge portion in the radiation image. And a technique for reducing the exposure time per frame of the X-ray tube according to the detected movement of the subject.

  Further, in Patent Document 2, imaging conditions for each part to be inspected are stored in advance in a storage unit, and imaging conditions according to the designated part to be inspected are read from the storage unit, set in the imaging apparatus, and set imaging A technique for performing dynamic imaging of a region to be inspected by an imaging apparatus under conditions is disclosed.

JP 2002-58665 A JP 2009-50531 A

  By the way, in radiographic moving image capturing / display, since the subject is continuously irradiated with radiation while the radiographing is being performed, there is a problem that the radiation exposure amount of the subject is likely to increase. On the other hand, if the update time interval of the radiation image displayed on the monitor is increased by increasing the radiation irradiation period of the subject in order to suppress the radiation exposure amount of the subject, for example, a radiation moving image when performing IVR In shooting where the shooting range changes during shooting, such as when shooting images, while fast moving organs such as the heart and lungs of the subject's organ are within the shooting range, The movement of the fast-moving organ becomes a discontinuous (poor smooth) movement such as so-called frame advance, which causes a problem that the visibility of the moving image is lowered.

  On the other hand, the technique described in Patent Document 1 reduces the exposure time per frame as the movement of the subject increases, and as the exposure time is reduced, blurring at the edge portion is reduced. However, the discontinuity of the movement of the subject on the moving image gets worse. The technique described in Patent Document 1 does not consider reduction of the radiation exposure amount of the subject, and reduces the radiation exposure amount of the subject and when a fast-moving object exists in the radiation detection range In addition, there is no disclosure of a specific configuration for simultaneously reducing the discontinuity of the motion of the object on the moving image.

  The technique described in Patent Document 2 captures a moving image using imaging conditions stored in advance for each region to be inspected, and does not consider reduction of the radiation exposure amount of the subject. Specific configuration for achieving both reduction of exposure dose and reduction of discontinuity of movement of an object on a moving image when a fast-moving object exists in a radiation detection range There is no disclosure about.

  The present invention has been made in consideration of the above-described facts. When a fast-moving object exists in the radiation detection range while suppressing the radiation exposure amount of the subject, the object on the moving image is displayed. It is an object to obtain a radiographic imaging apparatus that can reduce discontinuity of movement.

  In order to achieve the above object, a radiographic imaging apparatus according to the first aspect of the present invention includes an irradiation unit that intermittently irradiates radiation, and a radiation that detects radiation at a timing synchronized with the intermittent irradiation of the radiation by the irradiation unit. A detection control unit, a display control unit configured to display a radiation detection result by the radiation detection unit on a display unit as a moving image, and an object having a motion speed equal to or greater than a predetermined value within a radiation detection range by the radiation detection unit. Determining means for determining whether or not there is an object having a speed of movement equal to or greater than the predetermined value within the radiation detection range, and the speed of movement within the radiation detection range is equal to or greater than the predetermined value. 1st control which makes the irradiation time of the radiation per period in the intermittent irradiation of the radiation by the said irradiation means longer than the case where an object does not exist, or the said irradiation means A photographing control means for performing a second control to shorten the time interval of intermittent irradiation with, is configured to include a.

  In the first aspect of the present invention, radiation is intermittently emitted by the irradiating means, and the radiation detecting means detects the radiation at a timing synchronized with the intermittent irradiation of the radiation by the irradiating means, and the radiation detection result by the radiation detecting means is The moving image is displayed on the display means by the display control means. The determining means determines whether or not there is an object whose movement speed is greater than or equal to a predetermined value in the radiation detection range by the radiation detection means, and the imaging control means has a predetermined movement speed in the radiation detection range. When there is an object with a value greater than or equal to the value, the irradiation of radiation per cycle in the intermittent irradiation of radiation by the irradiation means is greater than when there is no object with a movement speed greater than or equal to a predetermined value within the radiation detection range. The first control for increasing the time or the second control for shortening the time interval of intermittent radiation irradiation by the irradiation means is performed.

  As a result, when the imaging control means has an object whose movement speed is greater than or equal to a predetermined value within the radiation detection range, there is no object whose movement speed is greater than or equal to the predetermined value within the radiation detection range. Rather than assuming that the first control to increase the irradiation time of the radiation per cycle in the intermittent irradiation of the radiation by the irradiation means, the amount of movement of the object during the period of irradiation of radiation increases, Although the blurring of the edge portion in the moving image may increase, the period in which no radiation is irradiated is shortened, and the amount of movement of the object in the period is reduced, so that the movement on the moving image is reduced. Fast object motion discontinuities are reduced.

  In addition, when there is an object whose movement speed is greater than or equal to a predetermined value within the radiation detection range, the imaging control unit is more than when there is no object whose movement speed is greater than or equal to the predetermined value within the radiation detection range. However, if the second control for shortening the time interval of intermittent irradiation of radiation by the irradiating means is performed, the period (time interval) of radiation detection by the radiation detecting means is shortened. By reducing the amount of movement of the object, the discontinuity of the movement of the fast moving object on the moving image is reduced. Therefore, when there is an object whose movement speed is greater than or equal to a predetermined value within the radiation detection range, the imaging control means performs the first control or the second control so that the object that moves quickly on the moving image. Motion discontinuity can be reduced.

  On the other hand, in the first aspect of the invention, when there is no object whose movement speed exceeds a predetermined value within the radiation detection range, the radiation irradiation time per cycle in the intermittent irradiation of radiation by the irradiation means. Since the time is shorter than the first control or the time interval of the intermittent irradiation of the radiation by the irradiation means is made longer than the second control, there is an object whose movement speed is a predetermined value or more in the radiation detection range. Irrespective of whether or not the first control or the second control is always performed, the radiation exposure amount of the subject is reduced during a period in which there is no object whose movement speed exceeds the predetermined value within the radiation detection range. Is done. Therefore, according to the first aspect of the present invention, when there is a fast-moving object in the radiation detection range while suppressing the radiation exposure amount of the subject, the discontinuity of the movement of the object on the moving image is detected. Can be reduced.

  In the first aspect of the invention, the first control is to reduce the image quality of the moving image when the radiation exposure amount of the subject per unit time is reduced by reducing the radiation dose irradiated by the irradiation means. It has the advantage that the degree of is small. In view of this, in the invention described in claim 1, for example, as described in claim 2, calculation means for calculating the radiation exposure dose of the subject is provided, and the imaging control means is configured to detect the subject calculated by the calculation means. When the cumulative radiation exposure dose exceeds a predetermined value, the first control is performed, and the radiation irradiated by the irradiation unit is greater than the case where there is no object whose movement speed exceeds the predetermined value within the radiation detection range. It is preferable to control so as to reduce the dose. Accordingly, it is possible to suppress the radiation exposure cumulative exposure amount of the subject while suppressing the deterioration of the image quality of the moving image due to the decrease in the radiation dose irradiated by the irradiation unit.

  In both the first control and the second control, a moving image in which the discontinuity of the movement of a fast moving object on the moving image is reduced can be obtained. While it has the advantage that the degree of image quality degradation of the moving image when the dose of radiation irradiated by the means is reduced, the blur of the edge portion in the moving image is larger than the moving image obtained by the second control The second control has the advantage that the blur of the edge portion in the moving image is small and a moving image with higher image quality than the first control can be obtained. There is a drawback that the exposure dose tends to increase.

  Considering that the first control and the second control have different characteristics as described above, in the invention according to claim 1 or 2, in the invention according to claim 1, for example, as described in claim 3, the first control Selection means is provided for selecting whether to perform the second control or the imaging control means, and the imaging control means is configured to perform the first control when the object whose movement speed is equal to or greater than a predetermined value exists within the radiation detection range. It is preferable that the second control is configured to perform a control selected in advance via a selection unit. Accordingly, it is possible to arbitrarily select whether to perform the first control or the second control according to various conditions such as the purpose of capturing the moving image, the imaging region, and the cumulative radiation exposure amount of the subject.

  Further, in the invention according to any one of claims 1 to 3, when the imaging control means performs the first control as described in claim 4, for example, the speed of movement is within the radiation detection range. You may comprise so that it may control so that the dose of the radiation irradiated by an irradiation means becomes smaller than the case where the object more than predetermined value does not exist. Accordingly, when the first control is performed by the imaging control unit, the deterioration of the image quality of the moving image due to the decrease in the dose of radiation irradiated by the irradiation unit is suppressed, and the radiation exposure amount of the subject is also suppressed. One control can be used as an imaging mode in which the radiation exposure amount of the subject is suppressed more than in the second control.

  Further, in the invention according to any one of claims 1 to 3, for example, as described in claim 5, a setting unit for setting a radiation dose is provided, and the imaging control unit is provided via the setting unit. The dose of radiation irradiated by the irradiation means may be changed according to the radiation dose set in the above. This makes it possible to arbitrarily set the dose of radiation irradiated by the irradiation means in accordance with various conditions such as the purpose of capturing the moving image, the imaging region, and the cumulative radiation exposure dose of the subject.

  Further, in the invention according to any one of claims 1 to 5, a lesion is obtained by inserting an insertion member into the body of the subject in parallel with radiographic image capturing / displaying by the radiographic image capturing device according to the present invention. For example, as described in claim 6, moving means for moving the irradiation means and the radiation detection means relative to the subject is provided, and the imaging control means is inserted into the body of the subject. The moving means causes the irradiation means, the radiation detection means, and the subject to move according to a change in the position of the distal end portion of the insertion member so that an image portion corresponding to the distal end portion of the insertion member is located within a predetermined region in the moving image. It is preferable to constitute so as to move relatively. This eliminates the need for the surgeon (therapist) to move the irradiation means, the radiation detection means, and the subject relative to the position of the distal end of the insertion member, thereby reducing the burden on the surgeon. Is done.

  Further, in the invention according to any one of claims 1 to 6, as an object for determining whether or not the determination means is present in the radiation detection range (an object whose movement speed is a predetermined value or more), For example, an organ whose movement speed is a predetermined value or more among the organs of the subject can be applied, and the movement speed as an object whose movement speed is a predetermined value or more is within a radiation detection range by the radiation detection means. For example, as described in claim 7, determining whether or not an organ having a value equal to or greater than the value is obtained by sequentially obtaining a single frame image representing a detection result of radiation by the radiation detection unit. And calculating a motion vector for each block when the image is divided into a plurality of blocks based on images of a plurality of continuous frames, and the calculated motion vector has a magnitude greater than or equal to a predetermined value, and A search is made as to whether or not there is a block group with motion composed of a plurality of blocks, and when the block group with motion is extracted, the corresponding block group is also obtained from images of frames within a predetermined number in the past. Is extracted as a block group with motion, and if the corresponding block group is extracted as a block group with motion, the motion speed of the block group with motion extracted this time is predetermined. This can be realized by repeating the process of determining a block group corresponding to an organ of a value or more.

  A radiographic imaging apparatus according to an eighth aspect of the invention includes an irradiation unit that intermittently irradiates radiation, a radiation detection unit that detects radiation at a timing synchronized with the intermittent irradiation of radiation by the irradiation unit, and the radiation detection Display control means for displaying the detection result of the radiation by the means on the display means as a moving image, and an organ whose movement speed is a predetermined value or more among the organs of the subject is within the radiation detection range by the radiation detection means In addition, the irradiation time of the radiation per cycle in the intermittent irradiation of the radiation by the irradiation means, so that the discontinuity of the movement on the moving image of the organ whose speed of movement is a predetermined value or more is reduced, or Imaging control means for changing the time interval of intermittent irradiation of radiation by the irradiation means.

  In the invention described in claim 8, as in the invention described in claim 1, the radiation is intermittently irradiated by the irradiation means, and the radiation is detected at a timing synchronized with the intermittent irradiation of the radiation by the irradiation means. The radiation detection result by the radiation detection means is displayed on the display means as a moving image by the display control means. Then, the imaging control means, on the moving image of the organ whose movement speed is equal to or higher than the predetermined value, when an organ whose movement speed is higher than the predetermined value is within the radiation detection range by the radiation detection means. In order to reduce the discontinuity of movement in the light source, the irradiation time of the radiation per cycle in the intermittent irradiation of the radiation by the irradiation means or the time interval of the intermittent irradiation of the radiation by the irradiation means is changed. Similar to the described invention, the discontinuity of the movement of the object on the moving image is reduced when there is a fast moving object in the radiation detection range while suppressing the radiation exposure amount of the subject. be able to.

  In the invention according to any one of claims 1 to 8, as the radiation detection means, for example, a configuration including a radiation conversion layer and a switching layer can be applied as described in claim 9. . In addition, the board | substrate which comprises a switching layer may be comprised from the material which permeate | transmits a radiation. In the case where the radiation detection means includes a radiation conversion layer and a switching layer, it is common to perform imaging by arranging the radiation detection means so that the radiation is irradiated from the radiation conversion layer side. If the substrate constituting the switching layer is made of a material that transmits radiation, it is possible to perform imaging by arranging a radiation detection means so that the radiation is irradiated from the switching layer side.

  Further, in the invention according to any one of claims 1 to 9, as the radiation detection means, for example, as described in claim 10, a portable radiation image detection that is detachable from the radiation imaging apparatus. The device can be applied.

  Further, in the invention according to any one of claims 1 to 10, the radiation detection means includes, for example, a light emitting unit that emits light by absorbing irradiated radiation, and the light emitting unit as described in claim 11. It is preferable that the light-emitting unit is disposed on the downstream side in the radiation arrival direction with respect to the light detection unit. In this configuration, compared to a case where radiation is incident from the light emitting unit side of the light emitting unit and the light detecting unit, a portion closer to the light detecting unit in the light emitting unit becomes the main light emitting region, and the amount of light received by the light detecting unit Therefore, the radiation detection sensitivity in the radiographic imaging apparatus can be improved.

  In the eleventh aspect of the invention, for example, as described in the twelfth aspect, it is preferable that the light emitting portion is made of a material containing CsI and a columnar crystal structure portion is formed. As a result, the light generated when the light emitting part absorbs radiation is guided to the gap between the columnar crystals and emitted to the light detecting means side in the columnar crystal structure part formed in the light emitting part. Since the diffusion of the light emitted to the means side is suppressed, it is possible to suppress a decrease in the sharpness of the image detected by the light detection means of the radiation detection means.

  As described above, according to the present invention, it is determined whether or not there is an object whose movement speed is a predetermined value or more in the radiation detection range, and there is an object whose movement speed is a predetermined value or more in the radiation detection range. The first control to increase the irradiation time of the radiation per cycle in the intermittent irradiation of the radiation, compared to the case where there is no object whose movement speed exceeds the predetermined value in the radiation detection range, or Since the second control for shortening the time interval of intermittent radiation irradiation is performed, a moving image is displayed when there is a fast moving object in the radiation detection range while suppressing the radiation exposure amount of the subject. It has an excellent effect that the discontinuity of the movement of the object can be reduced.

It is a perspective view which shows the mode of the operating room where the radiographic imaging system was installed. It is a perspective view which fractures | ruptures and shows the internal structure of an electronic cassette partially. It is a perspective view which shows the principal part structure of a radiation irradiation apparatus. It is sectional drawing which shows the structure of a mounting base, a supporting member, and its periphery. It is sectional drawing which shows the internal structure of a mounting base. It is sectional drawing which shows the structure of the periphery of a radiation irradiation apparatus. It is a block diagram which shows the structure of a radiographic imaging system. It is a circuit diagram which shows the equivalent circuit of the part corresponded to 1 pixel of a radiation detector. It is a flowchart which shows the content of a radiation moving image imaging | photography / display process. (A) is a diagram showing an example of exposure conditions at the time of normal imaging, and (B) and (C) are examples of exposure conditions at the time of imaging a pulsating organ. It is a flowchart which shows the content of the pulsating organ search process. It is an image figure for demonstrating a pulsating organ search process. It is sectional drawing which showed typically the other example of the structure of the radiation detector incorporated in the electronic cassette. It is the schematic which shows typically an example of the crystal structure of the scintillator in the radiation detector shown in FIG. It is a diagram which shows roughly the characteristic of CsI which can be used as a scintillator of a radiation detector. It is sectional drawing which showed typically the other example of the structure of the radiation detector incorporated in the electronic cassette.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a radiographic image capturing system 10 according to the present embodiment. The radiographic image capturing system 10 is used by an operator 12 or a radiographer to capture a radiographic image. The radiographic image capturing system 10 includes a bed 16 for a patient (subject) 14 to lie down, and a radiation dose corresponding to preset imaging conditions. A radiation irradiation device 18 that irradiates the patient 14 with radiation X and is movable along the longitudinal direction of the bed 16, and a portable type that generates and stores radiation image information by detecting the radiation X transmitted through the patient 14. An imaging device (hereinafter referred to as “electronic cassette”) 20, a support member 22 that is provided on one end side in the width direction of the bed 16 and supports the electronic cassette 20 and is movable along the longitudinal direction of the bed 16; A support member 22 that cantilever-supports the electronic cassette 20 on the side of the bed 16 where the patient 14 is placed, a radiation irradiation device 18, an electronic cassette 20, a first moving device 50 (described later), and Is configured to include a console 24 for controlling the operation of the second moving device 78 (described later), the.

  The electronic cassette 20 supported by the support member 22 is an example of the radiation detection means according to the present invention (more specifically, the radiation detection means according to claims 9 and 10), and transmits the radiation X as shown in FIG. A substantially rectangular flat plate-shaped casing 30 made of a material to be made is provided. When the electronic cassette 20 is used in an operating room or the like, there is a possibility that blood or other germs may adhere. For this reason, the housing | casing 30 is set as the structure which has high waterproofness and airtightness. Thereby, it becomes possible to repeatedly use the same electronic cassette 20 by sterilizing and cleaning as necessary.

  Inside the housing 30, the grid 34 that removes scattered radiation of the radiation X, the radiation detector 36, and the back scattered radiation of the radiation X are absorbed from the irradiation surface 32 side of the housing 30 irradiated with the radiation X. Lead plates 38 are arranged in order. The radiation detector 36 includes a substantially rectangular irradiation surface 36A to which the radiation X is irradiated, detects the radiation dose of the radiation X that is transmitted through the patient 14 and is irradiated to the irradiation surface 36A, and the radiation according to the radiation dose. Outputs radiation image information representing an image. Details of the radiation detector 36 will be described later.

  A case 40 that houses an electronic circuit including a microcomputer and a rechargeable secondary battery is disposed at one end of the housing 30. The radiation detector 36 and the electronic circuit are operated by electric power supplied from a secondary battery housed in the case 40. Here, in order to avoid various circuits housed in the case 40 from being damaged by the radiation X irradiation, a shielding member for shielding radiation such as a lead plate is disposed on the irradiation surface 32 side of the case 40. It is desirable to keep it. A connection terminal 20 </ b> A for connecting a communication cable is provided at a position corresponding to the case 40 on the side surface of the housing 30 of the electronic cassette 20.

  The radiation irradiation device 18 is an example of the irradiation means according to the present invention. As shown in FIG. 3, the radiation source 42 that emits the radiation X, and the four slit plates disposed on the radiation X emission side of the radiation source 42. 44A, 44B, 44C, and 44D. Each of the slit plates 44A to 44D is made of a material that shields radiation X such as lead or tungsten, and is shaped into a rectangular plate shape in plan view with a thickness gradually increased from the front end portion to the rear end portion. The diaphragm portion 44 is configured such that the tip portions of the slit plate 44A and the slit plate 44B face each other, and the tip portions of the slit plate 44C and the slit plate 44D face each other, and each of the slit plates 44A to 44D. Each of the slit plates 44A to 44D is arranged so that an opening region 51 having a rectangular shape in a plan view is formed by the tip of each of the slit plates 44A to 44D.

  The slit plate 44A and the slit plate 44B are movable in the direction of FIG. 3x, and the slit plate 44C and the slit plate 44D are movable in the direction of FIG. 3y perpendicular to the direction of FIG. 3x. The movable range of each of the slit plates 44A to 44D is such that the opening region 51 is rectangular in plan view from the position where the tip portions of the opposing slit plates contact each other (the fully closed state where the opening region 51 is fully closed). It is the range up to the position (full open state) where the shape is maintained and the maximum area is reached. The slit plate 44A moves when the driving force of the motor 160 (see FIG. 7) is transmitted through a transmission means (not shown), and the slit plate 44B does not show the driving force of the motor 162 (see FIG. 7). The slit plate 44C moves when the driving force of the motor 164 (see FIG. 7) is transmitted through a transmission means (not shown), and the slit plate 44D moves through the motor 166 ( The driving force is transmitted through a transmission means (not shown).

  The radiation irradiation device 18 is made of a material that shields the radiation X, such as lead and tungsten, and includes an accommodation box 53 (see FIG. 1) that accommodates the radiation source 42 and the diaphragm 44. As shown in FIG. 1, an opening 53 </ b> A for irradiating the electronic cassette 20 with the radiation X emitted from the radiation source 42 and passing through the aperture 44 is formed in the storage box 51.

  Here, the opening 52A transmits the radiation X according to the direct line of the radiation X passing through the opening region 51 and the thickness of each of the slit plates 44A to 44D when the slit plates 44A to 44D of the diaphragm 44 are fully opened. Both the radiation X (hereinafter referred to as “transmission line”) transmitted through the slit plates 44 </ b> A to 44 </ b> D with a dose can be emitted. Moreover, in the radiographic imaging system 10 which concerns on this embodiment, when each slit board 44A-44D of the aperture | diaphragm | squeeze part 44 is a full open state, the radiation X is irradiated to the whole irradiation surface 32 in the electronic cassette 20, The electronic cassette 20 and the radiation irradiation device 18 are positioned in advance.

  On the other hand, the bed 16 shown in FIG. 1 is made of a material that transmits the radiation X, and has a substantially rectangular flat plate-shaped mounting table 16A for the patient 14 to lie, and leg portions that are provided at the four corners of the mounting table 16A and support the mounting table 16A. 16B. A long groove 48 is formed along the longitudinal direction of the mounting table 16A on the one end side in the width direction of the mounting table 16A on the upper surface of the mounting table 16A. As shown in FIG. 4, a storage chamber 52 communicating with the outside through the long groove 48 is formed at a position corresponding to the long groove 48 in the inside of the mounting table 16 </ b> A. A part of the member 22 (base 54 to be described later) and a first moving device 50 that moves the support member 22 along the long groove 48 are accommodated.

  The support member 22 includes a base portion 54 accommodated in the accommodation chamber 52, a frame 56 attached to the upper surface of the base portion 54 and protruding onto the mounting table 16A via the long groove 48, and a base end portion in an L shape. A bent frame 58 is provided. A plurality of holes 60 are formed near the tip of the protruding portion of the frame 56 at positions different from each other along the protruding direction, and the frame 58 is inserted into any one of the plurality of holes 60. The bolts 62 are screwed into the base end portion of the frame 58 and are fastened and fixed to the frame 56. In addition, the casing 30 of the electronic cassette 20 is fastened and fixed to the front end portion of the frame 58 with bolts. Therefore, the height position of the electronic cassette 20 can be adjusted by changing the hole 60 through which the bolt 62 is inserted.

  The base 54 of the support member 22 is provided with a pair of flanges 54A that protrude in the width direction of the mounting table 16A, and a pair of long grooves 52A are formed on both side walls in the storage chamber 52. The pair of long grooves 52A are extended along the longitudinal direction of the mounting table 16A, and a pair of flanges 54A are fitted therein. Thereby, the support member 22 (and the electronic cassette 20) slides along the longitudinal direction of the mounting table 16A while maintaining the posture shown in FIGS. 1 and 4 by the flange 54A coming into contact with the inner wall surface of the long groove 52A. It can be moved.

  A first moving device 50 is disposed below the base portion 54 in the storage chamber 52. The first moving device 50 includes a motor 66 fixed to the lower surface 54B of the base 54, a driving device 68 that is also fixed to the lower surface 54B of the base 54 and drives the motor 66 in accordance with instructions from the console 24, and a driving force of the motor 66. And a rack gear 69 disposed on the bottom surface of the storage chamber 52 and extending along the longitudinal direction of the mounting table 16A. As shown in FIG. 5, the gear unit 64 includes a drive gear 64 </ b> A attached to the rotation shaft of the motor 66, and a pinion gear 64 </ b> B that meshes with the drive gear 64 </ b> A and the rack gear 69. Thereby, when the motor 66 is driven by the driving device 68, the support member 22 (and the electronic cassette 20) slides in the direction of the arrow A or the arrow B in FIG. Moved.

  Further, below the mounting table 16A, a support body 70 is formed in a rectangular parallelepiped-shaped container 74 that extends along the longitudinal direction of the mounting table 16A and in a direction in which the patient 14 on the mounting table 16A is irradiated with the radiation X. And a radiation irradiation device 18 supported by. A long groove 76 is formed on the upper surface of the container 74 along the longitudinal direction of the mounting table 16A. As shown in FIG. 6, a storage chamber 80 communicating with the outside through a long groove 76 is formed inside the storage body 74. The support member 70 includes a base 72 housed in the housing chamber 80, and a frame 73 attached to the upper surface of the base 72 and protruding toward the mounting table 16 </ b> A via a long groove 76. The radiation irradiation device 18 is fixed. The container 74 has a central position along the width direction of the mounting table 16A in the irradiation range of the radiation X from the radiation irradiation device 18, and the electronic cassette 20 supported by the support member 22 along the longitudinal direction. Among them, the position along the width direction of the mounting table 16A is adjusted so as to substantially coincide with the center position along the width direction of the mounting table 16A.

  The base 72 of the support member 70 is provided with a pair of flanges 72 </ b> A protruding in the width direction of the mounting table 16 </ b> A, and a pair of long grooves 80 </ b> A are formed on both side walls in the storage chamber 80. The pair of long grooves 80A are extended along the longitudinal direction of the mounting table 16A, and a pair of flanges 72A are fitted therein. Thereby, the support member 70 (and the radiation irradiation apparatus 18) is along the longitudinal direction of the mounting table 16A while maintaining the posture shown in FIGS. 1 and 6 by the flange 72A being in contact with the inner wall surface of the long groove 80A. The sliding movement is possible.

  A second moving device 78 is disposed below the base 72 in the accommodation chamber 80. The first moving device 78 includes a motor 84 fixed to the lower surface 72B of the base 72, a driving device 86 that is also fixed to the lower surface 72B of the base 72 and drives the motor 84 in accordance with an instruction from the console 24, and a driving force of the motor 84. And a rack gear 85 disposed on the bottom surface of the storage chamber 80 and extending along the longitudinal direction of the mounting table 16A. The gear unit 82 includes a drive gear 82A attached to the rotation shaft of the motor 84, and a pinion gear 82B that meshes with the drive gear 82A and the rack gear 85. Thus, when the motor 84 is driven by the drive device 86, the support member 70 (and the radiation irradiation device 18) slides in the direction of arrow A or arrow B in FIG. 1 according to the rotation direction of the rotation shaft of the motor 84. It is moved.

  Next, the configuration of the electrical system of the radiographic imaging system 10 will be described with reference to FIG. The radiation irradiation device 18 is provided with a connection terminal 18 </ b> A for communicating with the console 24. Further, the console 24 includes a connection terminal 24A for communicating with the radiation irradiation device 18, a connection terminal 24B for communicating with the electronic cassette 20, an antenna 24C for performing wireless communication with the first mobile device 50, and a second. An antenna 24D for performing wireless communication with the mobile device 78 is provided.

  The radiation irradiation device 18 is connected to the console 24 by connecting the other end of the communication cable 90 having one end connected to the connection terminal 18A to the connection terminal 24A. The electronic cassette 20 is connected to the console 24 by connecting one end of the communication cable 92 to the connection terminal 20A and connecting the other end of the communication cable 92 to the connection terminal 24B at the time of radiographic image capturing. In this embodiment, in order to increase the speed of data transfer between the electronic cassette 20 and the console 24, an optical communication cable is used as the communication cable 92, and optical communication is performed between the electronic cassette 20 and the console 24. Data transfer is performed by communication.

  The radiation detector 36 incorporated in the electronic cassette 20 is configured by laminating a photoelectric conversion layer that absorbs radiation X and converts it into charges on a TFT (Thin Film Transistor) active matrix substrate 94. The photoelectric conversion layer is made of amorphous a-Se (amorphous selenium) containing, for example, selenium as a main component (for example, a content rate of 50% or more), and when irradiated with radiation X, a charge corresponding to the amount of irradiated radiation. By generating a certain amount of charge (electron-hole pairs) internally, the irradiated radiation X is converted into a charge. The radiation detector 36 is indirectly charged using a phosphor material and a photoelectric conversion element (photodiode) instead of a radiation-charge conversion material that directly converts the radiation X such as amorphous selenium into an electric charge. It is also possible to convert to Known phosphor materials include gadolinium sulfate (GOS) and cesium iodide (CsI). In this case, radiation-light conversion is performed by the phosphor material, and light-charge conversion is performed by the photodiode of the photoelectric conversion element.

  In addition, on the TFT active matrix substrate 94, a pixel unit 100 including a storage capacitor 96 for storing charges generated in the photoelectric conversion layer and a TFT 98 for reading out the charges stored in the storage capacitor 96 (FIG. 7). In this figure, a large number of photoelectric conversion layers corresponding to the individual pixel units 100 are schematically shown as photoelectric conversion units 102), and photoelectric conversion is performed in accordance with irradiation of the electronic cassette 20 with radiation X. The charges generated in the layers are stored in the storage capacitors 96 of the individual pixel units 100. Thereby, the radiation image information carried on the radiation X irradiated to the electronic cassette 20 is converted into charge information and held in the radiation detector 36.

  The TFT active matrix substrate 94 is extended in a certain direction (row direction), a plurality of gate lines 104 for turning on and off the TFTs 98 of the individual pixel portions 100, and a direction (column) orthogonal to the gate lines 104. A plurality of data wirings 106 are provided for reading out stored charges from the storage capacitor 96 through the TFTs 98 that are turned on and turned on. The individual gate lines 104 are connected to the gate line driver 108, and the individual data lines 106 are connected to the signal processing unit 110. When charges are stored in the storage capacitors 96 of the individual pixel units 100, the TFTs 98 of the individual pixel units 100 are sequentially turned on in units of rows by a signal supplied from the gate line driver 108 via the gate wiring 104. The charge stored in the storage capacitor 96 of the pixel unit 100 for which is turned on is transmitted as a charge signal through the data wiring 106 and input to the signal processing unit 110. Accordingly, the charges accumulated in the storage capacitors 96 of the individual pixel units 100 are sequentially read out in units of rows.

  As shown in FIG. 8, the source of the TFT 98 is connected to the data line 106, and the data line 106 is connected to the signal processing unit 110. The drain of the TFT 98 is connected to the storage capacitor 96 and the photoelectric conversion unit 102, and the gate of the TFT 98 is connected to the gate wiring 104. The signal processing unit 110 includes a sample hold circuit 112 for each data wiring 106. The charge signal transmitted through each data line 106 is held in the sample hold circuit 112. The sample hold circuit 112 includes an operational amplifier 112A and a capacitor 112B, and converts the charge signal into an analog voltage. In addition, the sample hold circuit 112 is provided with a switch 112C that acts as a reset circuit that discharges charges accumulated in the capacitor 112B by short-circuiting both electrodes of the capacitor 112B.

  A multiplexer 114 and an A / D (analog / digital) converter 116 are sequentially connected to the output side of the sample and hold circuit 112, and the charge signals held in the individual sample and hold circuits are converted into analog voltages to be converted into the multiplexer 114. Are sequentially input (serially) and converted into digital radiographic image information by the A / D converter 116.

  As shown in FIG. 7, the line memory 118 is connected to the signal processing unit 110, and the radiation image information output from the A / D converter 116 of the signal processing unit 110 is stored in the line memory 118 in order. The line memory 118 has a storage capacity capable of storing radiographic image information representing a radiographic image for a predetermined number of lines. Each time the charge is read out line by line, the read out radiographic image information for one line is stored. The data are sequentially stored in the line memory 118.

  The line memory 118 is connected to a cassette control unit 120 that controls the operation of the entire electronic cassette 20. The cassette control unit 120 is composed of a microcomputer, and an optical communication control unit 122 is connected thereto. The optical communication control unit 122 is connected to the connection terminal 20A, and controls transmission of various types of information with an external device (for example, the console 24) connected via the connection terminal 20A. Therefore, the cassette control unit 120 can transmit and receive various types of information to and from external devices via the optical communication control unit 122.

  The electronic cassette 20 includes a cassette control unit 120 and a power supply unit 126. The above-described various circuits and elements (gate line driver 108, signal processing unit 110, line memory 118, optical communication control unit 122, and cassette control unit). The microcomputer functioning as 120 is operated by the power supplied from the power supply unit 126. The power supply unit 126 has a built-in battery (a rechargeable secondary battery) so as not to impair the portability of the electronic cassette 20, and supplies power from the charged battery to various circuits and elements.

  On the other hand, the console 24 includes, for example, a server computer and the like, and includes a display 136 for displaying an operation menu, a captured radiographic image, and the like, and a plurality of keys, and inputs various information and operation instructions. And an operation panel 140.

  The console 24 also includes a CPU 128 that controls the overall operation of the apparatus, a ROM 130 in which control programs and the like are stored in advance, a RAM 132 that temporarily stores various data, various data, and radiographic image capturing / display processing described later. Operation status of an HDD (Hard Disk Drive) 134 in which various application programs including a radiological moving image capturing / display program for execution are installed, a display driver 138 for controlling display of various information on the display 136, and an operation panel 140 The operation input detection unit 142 for detecting the radiation, and transmission / reception of various kinds of information such as the exposure conditions and the state information of the radiation irradiation apparatus 18 to / from the radiation irradiation apparatus 18 via the connection terminal 24A and the communication cable 90 connected to the connection terminal 24A. Interface (I / F) unit 144 for performing connection An optical communication control unit 146 that is connected to the terminal 24B and transmits / receives various information such as image information to / from the electronic cassette 20 via the connection terminal 24B and the communication cable 92, and is connected to the antenna 24C and the first mobile device 50. A wireless communication control unit 148 that performs wireless communication with each other and a wireless communication control unit 150 that is connected to the antenna 24D and performs wireless communication with the second mobile device 78 are provided via a system bus. Are connected to each other.

  The radiation irradiation apparatus 18 includes an irradiation apparatus control unit 156 that controls the operation of the radiation irradiation apparatus 18 as a whole. The irradiation device control unit 156 is composed of a microcomputer, and a communication I / F unit 154 is connected thereto. The communication I / F unit 154 is connected to the connection terminal 18A, and controls transmission of various types of information between the connection terminal 18A and the console 24 connected via the communication cable 90. Therefore, the irradiation apparatus control unit 156 can transmit and receive various types of information to and from the console 24 via the communication I / F unit 154. The radiation source control unit 156 is connected to the radiation source 42, and the irradiation device control unit 156 controls the radiation source 42 based on the exposure conditions received from the console 24 via the communication I / F unit 154. To do.

  In addition, the radiation irradiation device 18 includes a motor 160 that generates a driving force for moving the slit plate 44A, a motor 162 that generates a driving force for moving the slit plate 44B, and a driving force for moving the slit plate 44C. And a motor driver 168 that controls the driving of the motor 160, and a motor driver 170 that controls the driving of the motor 162. A motor driver 172 that controls the driving of the motor 164 and a motor driver 174 that controls the driving of the motor 166 are also provided.

  The motor 160 is connected to the irradiation device controller 156 via the motor driver 168, the motor 162 is connected to the irradiation device controller 156 via the motor driver 170, and the motor 164 is connected to the irradiation device controller 156 via the motor driver 172. The motor 166 is connected to the irradiation device control unit 156 via the motor driver 174. Accordingly, the driving of the motors 160, 162, 164, 166 is controlled by the irradiation device controller 156 in accordance with instructions from the console 24.

  In addition to the motor 66 and the driving device 68, the first moving device 50 includes an antenna 50 </ b> A for performing wireless communication with the console 24. The driving device 68 wirelessly communicates with the controller 68A that controls the operation of the entire first moving device 50, the motor driver 68B that controls the driving of the motor 66, and the console 24 that is connected to the antenna 50A and via the antenna 50A. And a power supply unit 68D that supplies power to the controller 68A, the motor driver 68B, the wireless communication control unit 68C, and the motor 66.

  The controller 68A includes a microcomputer, and is connected to a motor driver 68B and a wireless communication control unit 68C. The controller 68A controls the driving of the motor 66 via the motor driver 68B according to the instruction from the console 24, grasps the driving state of the motor 66, and sends information indicating the driving state via the wireless communication control unit 68C. Send to console 24.

  In addition to the motor 84 and the drive device 86, the second moving device 78 includes an antenna 78 </ b> A for performing wireless communication with the console 24. The driving device 86 is wirelessly communicated between the controller 86A that controls the operation of the entire second moving device 78, the motor driver 86B that controls the driving of the motor 84, and the console 24 connected to the antenna 78A via the antenna 78A. A wireless communication control unit 86 </ b> C that performs power supply, a controller 86 </ b> A, a motor driver 86 </ b> B, a wireless communication control unit 86 </ b> C, and a power supply unit 86 </ b> D that supplies power to the motor 84.

  The controller 86A includes a microcomputer, and is connected to a motor driver 86B and a wireless communication control unit 86C. The controller 86A controls the drive of the motor 84 via the motor driver 86B according to the instruction from the console 24, grasps the drive state of the motor 84, and sends information indicating the drive state via the wireless communication control unit 86C. Send to console 24.

  Next, as an operation of the present embodiment, when performing an IVR in which a catheter is inserted into a blood vessel of a patient (subject) 14 lying on a bed 16 while using the radiographic imaging system 10 according to the present embodiment, an operation is performed. Radiation moving image capturing / display processing performed on the console 24 in response to an instruction from the person 12 will be described with reference to FIG. Note that this radiation moving image capturing / displaying process is realized by the CPU 128 executing a radiation moving image capturing / displaying program installed in the HDD 134. In addition, when the execution of radiographic image capturing / display processing is started, a catheter (specifically, a guide wire for leading the catheter in the body of the patient (subject) 14: an example of the insertion member according to claim 6). The relative positions of the radiation irradiation device 18 and the electronic cassette 20 with respect to the body of the patient (subject) 14 are adjusted in advance by the operator 12 so that the insertion opening and the periphery thereof are within the imaging range.

  In the radiation moving image capturing / display processing, first, in step 200, the radiation image capturing system 10 captures a moving image of the patient (subject) 14 during the IVR, as a radiation exposure condition by the radiation irradiation device 18. A predetermined condition is set as an exposure condition in normal moving image shooting. When capturing a moving image of the patient (subject) 14, the radiation irradiation device 18 intermittently irradiates the patient (subject) 14 with radiation as shown in FIG. For this reason, the exposure conditions in moving image shooting include the radiation irradiation cycle T, the radiation irradiation dose W, and the radiation irradiation time t. In step 200, the above items are used for normal moving image shooting. Each predetermined value is set (irradiation period T ← T1, irradiation dose W ← W1, irradiation time t ← t1: see also FIG. 10A).

  In the present embodiment, the exposure condition in normal moving image shooting is such that the value of each item is prioritized to reduce the radiation exposure of the patient (subject) 14 over the image quality of the moving image to be shot. Specifically, the irradiation time t is shortened compared to moving image shooting in the irradiation time increasing mode described later, and the irradiation cycle T compared to moving image shooting in the high rate mode described later. Has been long.

  In step 202, the pulsating organ imaging flag is set to 0, and in the next step 204, the current setting values of the radiation irradiation period T, the radiation irradiation dose W, and the radiation irradiation time t are set as the radiation exposure conditions (in this case, in step 200). The set value) is notified to the radiation irradiating device 18 and the radiation emission (irradiation) is instructed under the notified exposure condition. Thereby, in the radiation irradiation apparatus 18, the radiation exposure by the radiation source 42 is controlled by the irradiation apparatus control unit 156 according to the exposure conditions notified from the console 24. From the radiation source 42, as shown in FIG. As shown in FIG. 4, in the irradiation period T1, the radiation having the irradiation dose W1 is emitted for the irradiation time t1, and the radiation emitted from the radiation source 42 and transmitted through the diaphragm 44 is irradiated to the patient (subject) 14.

  In the next step 206, it is determined whether or not the irradiation of radiation within one period of irradiation is completed, and step 206 is repeated until the determination is affirmed. If the determination in step 206 is affirmed, the process proceeds to step 208, where the electronic cassette 20 is instructed to read out the charges accumulated in the storage capacitors 96 of the individual pixel units 100 on the TFT active matrix substrate 94. Radiation image data obtained by reading (image data corresponding to one frame of a radiation moving image) is acquired by receiving from the electronic cassette 20, and the acquired data is stored in the HDD 134 and the radiation represented by the data is displayed. An image corresponding to one frame of the moving image is displayed on the display 136. This step 208 is an example of processing corresponding to the display control means.

  In step 210, based on the radiographic image (image corresponding to one frame of the radiographic moving image) represented by the data acquired from the electronic cassette 20 in step 208, the position of the distal end portion of the catheter guide wire on the image is detected. Since the guide wire of the catheter is greatly different in the radiation absorption rate from each part of the human body, the density of the image part corresponding to the guide wire of the catheter is clearly different from other image parts on the radiographic image. . Accordingly, the position of the distal end portion of the guide wire of the catheter on the radiographic image is binarized by, for example, a threshold value that can distinguish the image portion corresponding to the guide wire of the catheter and other image portions, and after binarization. Detection is performed by performing image processing such as thinning the image portion corresponding to the guide wire of the catheter on the radiographic image and recognizing the position of the end of the curve obtained by thinning as the position of the tip of the guide wire. be able to.

  In the next step 212, a pulsating organ search process is performed. This pulsating organ search process corresponds to a pulsating organ (for example, heart, lung, etc.) whose movement speed is greater than or equal to a predetermined value among the organs of the patient (subject) 14 in the radiographic image acquired in step 208. This is a process of searching for / determining whether or not an image portion exists and outputting “with pulsating organ” or “without pulsating organ” as a determination result, which will be described in detail later. Step 212 is an example of determination means according to the present invention. In the next step 214, it is determined whether or not the determination result of the pulsating organ search process in step 212 is “there is a pulsating organ”. If the determination is negative, the process proceeds to step 216, and it is determined whether or not the pulsating organ imaging flag is 1.

  If this determination is negative, the process proceeds to step 238, and it is determined whether or not it is necessary to move the range of the body of the patient (subject) 14 that the radiographic imaging system 10 captures. This determination is made, for example, when the position of the distal end portion of the guide wire of the catheter detected in the previous step 210 is a predetermined range on the radiographic image (for example, a range within a predetermined distance from the center of the radiographic image, or predetermined from the outer edge of the radiographic image). This can be done by judging whether or not there is a deviation from the remaining range excluding the range within the distance.

  If this determination is denied, the process proceeds to step 242; if the determination in step 238 is affirmed, the process proceeds to step 240, and the distal end portion of the guide wire of the catheter whose position is detected in step 210 is displayed on the radiographic image. The movement direction and movement amount of the radiation irradiation device 18 and the electronic cassette 20 for positioning within the predetermined range are calculated, and the calculated movement direction and movement amount are notified to the first movement device 50 and the second movement device 78. Thus, the radiation irradiation device 18 and the electronic cassette 20 are moved by the calculated movement amount in the calculated movement direction. As a result, the position of the distal end of the guide wire of the catheter moves in the blood vessel of the patient (subject) 14 as the IVR progresses, and the radiographic imaging system of the body of the patient (subject) 14 The range in which the camera 10 shoots moves. Note that the above-described steps 238 and 240 are an example of processing by the photographing control means according to the sixth aspect.

  In the next step 242, it is determined whether or not the surgeon 12 has instructed the radiographic imaging system 10 to end moving image capturing with the end of IVR. If this determination is negative, the process returns to step 204, and steps 204 to 216 and steps 238 to 242 are repeated. As a result, the patient (subject) 14 is irradiated with radiation by the radiation irradiating apparatus 18 under normal moving image exposure conditions, the radiation is detected by the electronic cassette 20, and the radiation image data is acquired from the electronic cassette 20. Are repeated, and a radiation moving image photographed under normal moving image photographing exposure conditions is displayed on the display 136. As described above, while there is no image portion corresponding to a pulsating organ in the radiation moving image, the exposure condition in normal moving image shooting (the exposure condition in which the irradiation time t is short and the irradiation cycle T is long). Accordingly, the patient (subject) 14 is irradiated with radiation, and a moving image is captured and displayed. Therefore, the radiation exposure amount of the patient (subject) 14 is suppressed to a low level.

  By the way, when the IVR progresses and the imaging range of the radiographic image by the radiographic imaging system 10 in the body of the patient (subject) 14 moves, the pulsating organ of the patient (subject) 14 becomes a radiation by the radiographic imaging system 10. Although it may fall within the imaging range of the image, in this case, the movement of the pulsating organ on the radiation moving image displayed on the display 136 becomes a discontinuous (less smooth) movement such as so-called frame advance. This causes a problem that the visibility of the radiation moving image is lowered. On the other hand, in the radiographic moving image capturing / display processing (FIG. 9) according to the present embodiment, when the pulsating organ enters the radiographic image capturing range, the determination result of the pulsating organ searching process in step 212 is “Pulsed organ present”. Thus, the determination at step 214 is affirmed and the routine proceeds to step 222. After step 222, the radiation exposure condition by the radiation irradiating apparatus 18 is switched to the exposure condition for pulsating organ imaging.

  That is, first, in step 222, the radiation exposure dose of the patient (subject) 14 after the start of the radiographic image capturing / display process is calculated. Since the radiation exposure amount per one cycle of radiation irradiation can be calculated from the irradiation dose W and the irradiation time t in that cycle, the cumulative radiation exposure amount of the patient (subject) 14 after the start of the radiographic image capturing / display processing is started. Can be obtained by calculating the radiation exposure dose in each cycle of radiation irradiation and adding them all. In addition, once the cumulative radiation exposure has been calculated, the radiation exposure at each time point during the radiographic image capture / display process is added by sequentially adding the radiation exposure in each subsequent period. The exposure dose can be determined. Note that step 222 is an example of a computing means described in claim 2.

  By the way, in this embodiment, as a photographing mode when a pulsating organ is included in the radiographic image photographing range (at the time of pulsating organ photographing), two kinds of photographing modes having different radiation exposure conditions (irradiation time increasing mode). And high rate mode). The irradiation time increase mode is a moving image under an exposure condition in which the irradiation time t is longer than the exposure condition in normal moving image shooting so that the discontinuity of the motion of the pulsating organ on the moving image is reduced. This is a mode for taking an image, and is an example of the first control according to the present invention. In the high-rate mode, a moving image is recorded under an exposure condition in which the irradiation period T is shorter than the exposure condition in the normal moving image shooting so that the discontinuity of the motion of the pulsating organ on the moving image is reduced. This is a mode for taking an image, and is an example of second control according to the present invention.

  In both the irradiation time increase mode and the high rate mode, a moving image in which discontinuity of the motion of the pulsating organ on the moving image is reduced can be obtained. However, in the irradiation time increase mode, the irradiation dose W is reduced. Has the advantage that the degree of image quality degradation of the moving image is small, while the blur of the edge portion in the moving image has a disadvantage that it is larger than the moving image obtained by the high rate mode, Disadvantage that the radiation dose of the patient (subject) 14 tends to be large while the blur of the edge portion in the moving image is small and has the advantage that a high-quality moving image can be obtained as compared with the irradiation time increase mode. have.

  Therefore, in this embodiment, the surgeon determines whether to apply the irradiation time increase mode or the high rate mode as the imaging mode when the pulsating organ is within the imaging range of the radiation image (during pulsating organ imaging). 12 can be selected, and the operator 12 can also set the irradiation dose W at the time of imaging of the pulsating organ. The operator 12 can select the pulsating organ corresponding to the imaging purpose of the moving image and the imaging site (the imaging site). Taking into account various conditions such as the required image quality for moving images at the time of imaging) and the radiation exposure dose of the patient (subject) 14, either the irradiation time increasing mode or the high rate mode is selected as the imaging mode for pulsating organ imaging. The irradiation dose W at the time of pulsating organ imaging is set in advance via the operation panel 140. The operation panel 140 when the above operation is performed corresponds to a selection unit according to a third aspect and a setting unit according to a fifth aspect. Note that the imaging mode and the irradiation dose W at the time of pulsating organ imaging can be changed during the radiographic image capturing / displaying process.

  The processing after the next step 224 is an example of processing by the imaging control means according to the present invention. First, at step 224, it is determined whether or not the cumulative radiation exposure dose calculated at step 222 is greater than or equal to a predetermined value. If the determination is negative, the process proceeds to step 230, where a value set in advance as the irradiation dose W (if the irradiation dose W has been set in advance by the operator 12, that value is not set by the operator 12). Set the default value). Step 230 is an example of processing by the photographing control means according to claim 4. In the next step 232, it is determined whether the mode set as the imaging mode at the time of pulsating organ imaging is the irradiation time increase mode or the high rate mode, and the process branches according to the determination result. Step 232 is an example of processing by the photographing control means according to claim 3.

  If the irradiation time increase mode is set as the imaging mode at the time of pulsating organ imaging, the process proceeds from step 232 to step 228, and the irradiation period T and irradiation time t are determined in advance as the irradiation time increasing mode at the time of pulsating organ imaging. Each set value is set (irradiation cycle T ← T1, irradiation time t ← t2: see also FIG. 10B). In the next step 236, 1 is set to the pulsating organ imaging flag, and the process proceeds to step 238. As described above, the exposure time in the irradiation time increase mode has the irradiation time t longer than the exposure condition in normal moving image shooting (t2> t1), whereby FIG. As apparent from comparison with FIG. 10 (A), the period during which the patient (subject) 14 is not irradiated with radiation (the period during which imaging is not performed as a radiographic image) is shortened, and the amount of motion of the pulsating organ during the period is reduced. As a result, discontinuity of the motion of the pulsating organ on the radiation moving image is reduced. In addition, since the period that is not imaged as a radiographic image is shortened, even when there is an important instantaneous motion change in the pulsating organ, the possibility that the motion change is imaged increases, It is possible to reduce the possibility that the viewer (for example, the operator 12) misses an important momentary change in the pulsating organ.

  The irradiation period T in the irradiation time increase mode is not set to the same as the irradiation period T (= T1) in the normal moving image shooting as described above, and the patient (subject) 14 is not irradiated with radiation. The value may be changed together with the irradiation time t within a range in which the period is shorter than that of normal moving image shooting.

  When the high rate mode is set as the imaging mode at the time of pulsating organ imaging, the process proceeds from step 232 to step 234, and the irradiation period T and the irradiation time t are determined in advance as the high rate mode at the time of pulsating organ imaging. Each set value is set (irradiation period T ← T2, irradiation time t ← t3: see also FIG. 10C). In step 236, 1 is set in the pulsating organ imaging flag, and the flow proceeds to step 238. As described above, in the high-rate mode exposure condition, the irradiation cycle T is shorter than the exposure condition in normal moving image shooting (T2 <T1), and thus, during one cycle of radiation irradiation. By reducing the amount of movement of the pulsating organ, discontinuity of the movement of the pulsating organ on the radiation moving image is reduced. Further, although the number of frames per unit time of the radiation moving image increases by shortening the irradiation period T, the viewer of the radiation moving image (for example, the surgeon 12) is accompanied by an important moment of the pulsating organ. The possibility of missing a change in motion can be reduced.

  In FIG. 10C, the irradiation time t (= t3) in the high-rate mode is shown as the same length as the irradiation time t (= t1) in normal moving image shooting, but the irradiation in the high-rate mode is performed. It goes without saying that the value may be different from the irradiation time t (= t1) in normal moving image shooting according to the cycle T (= T2).

  As described above, while the pulsating organ is within the radiographic image capturing range, the irradiation time increasing mode in which the irradiation time t is longer than the exposure condition in the normal moving image capturing, or in the normal moving image capturing. By taking a moving image in a high-rate mode in which the irradiation period T is shorter than the exposure condition, discontinuity of the motion of the pulsating organ on the radiation moving image is reduced, and the visibility of the radiation moving image is improved. Since it improves, effects, such as a fatigue reduction of the operator 12, are acquired. In addition, as an imaging mode at the time of pulsating organ imaging, it is possible to select either an irradiation time increase mode or a high rate mode having mutually different characteristics. More appropriate imaging mode can be selected according to various conditions such as the required image quality for the moving image) and the radiation exposure dose of the patient (subject) 14.

  Further, for example, when the radiation exposure time of the patient (subject) 14 after the start of the radiographic image capturing / displaying process exceeds a predetermined value due to, for example, a prolonged IVR, step 224 is performed. The determination is affirmed and the routine proceeds to step 226. After setting a preset value W2 as the irradiation dose W, the routine proceeds to step 228. In this case, a moving image is captured in an imaging range including a pulsating organ in the irradiation time increasing mode under the irradiation conditions of irradiation cycle T = T1, irradiation time t = t2, and irradiation dose W = W2. Note that performing the processing in step 226.228 when the determination in step 224 is affirmative is an example of processing by the imaging control unit according to claim 2.

  The above-mentioned irradiation dose W2 has the advantage that the degree of deterioration of the image quality of the moving image when the irradiation time increase mode decreases the irradiation dose W is small. Is set to a minimum value or a value close to the minimum value of the irradiation dose with which a moving image with a constant image quality is obtained. Therefore, after the cumulative radiation exposure dose of the patient (subject) 14 reaches a predetermined value, even if the high rate mode is set as the imaging mode at the time of pulsating organ imaging, the pulsating organ is within the imaging range of the radiographic image. While entering, a moving image is shot in the irradiation time increasing mode in which the irradiation dose W is suppressed (W = W2), and while suppressing the radiation exposure dose of the patient (subject) 14 from being excessive, A moving image with reduced discontinuity of motion of the pulsating organ on the radiation moving image is captured.

  Further, when the pulsating organ deviates from the radiographic image capturing range as the radiographic image capturing range further moves, the determination result of the pulsating organ search process in step 212 is “no pulsating organ”. Although the determination of 214 is denied, in this case, since the pulsating organ imaging flag is 1, the determination of step 216 is affirmed and the process proceeds to step 218, and in the same manner as in step 200 described above, the radiation As the exposure conditions, exposure conditions for normal moving image shooting are set (irradiation period T ← T1, irradiation dose W ← W1, irradiation time t ← t1). In step 220, the pulsating organ imaging flag is returned to 0, and the process proceeds to step 238.

  Thereby, it returns to the state which performs radiation | emission irradiation and imaging | photography / display of a moving image according to the exposure conditions in normal moving image imaging | photography, and it is suppressed that the radiation exposure dose of the patient (subject) 14 becomes excessive. It will be. When the IVR ends and the operator 12 instructs the end of moving image shooting by the radiographic image capturing system 10, the determination in step 242 is affirmed, and the radiation moving image capturing / display processing ends.

  Next, details of the pulsating organ search process performed in step 212 of the radiographic moving image capturing / display process (FIG. 9) will be described with reference to FIG. Note that the pulsating organ search process described below is an example of a process performed by the determination unit according to the eighth aspect. In the pulsating organ search process shown in FIG. 11, first, in step 250, a plurality of radiographic images to be processed (the latest radiographic image acquired in step 208 immediately before radiographic moving image capturing / display processing (FIG. 9)) are obtained. Divide into blocks. In the next step 252, the radiation image data acquired in the previous cycle is read from the HDD 134. In step 254, blocks that have not been subjected to the subsequent processing (the processing in steps 256 and 258) among the plurality of blocks obtained by dividing the radiation image to be processed in the previous step 250 are processed. Select as a block.

  In the next step 256, a search range is set on the radiation image of the previous cycle read in the previous step 252 with reference to the position of the block to be processed on the radiation image of the processing target. While moving the reference block within the search range set to, the calculation of the error between the processing target block and the reference block is repeated, so that the reference block that minimizes the error from the processing target block is the radiation of the previous period. Search within the search range on the image. When the reference block with the smallest error from the processing target block is extracted from the search range on the radiation image of the previous period, in the next step 258, the shift between the processing target block and the extracted reference block is performed. The amount and direction of displacement are obtained as motion vectors, and the obtained motion vectors are added to the block to be processed as attribute information.

  In the next step 260, it is determined whether or not the processing in steps 256 and 258 has been performed on all the blocks obtained by dividing the radiation image to be processed. If the determination is negative, the process returns to step 254, and steps 254 to 260 are repeated until the determination in step 260 is affirmed. Thereby, as shown in FIG. 12B as an example, motion vectors from the radiation image of the previous cycle are calculated and set for all the blocks constituting the radiation image to be processed. In the example shown in FIG. 12B, illustration of motion vectors is omitted for blocks whose motion vectors are less than a predetermined value.

  By the way, as shown in FIG. 12 (A) as an example, FIG. 12 (B) shows a plurality of radiographic images obtained by photographing an imaging range including a part of the heart and lung which are pulsating organs. An example of the result of dividing into blocks and calculating a motion vector is shown. As indicated by the hatched lines in FIG. 12B, a block corresponding to a pulsating organ among a plurality of blocks has a magnitude of a motion vector. Are both equal to or greater than a predetermined value and adjacent to each other. Based on this, in the next step 262, whether or not there is a block group consisting of a plurality of adjacent blocks having a motion vector magnitude greater than or equal to a predetermined value (hereinafter, this block group is referred to as a “block group with motion”). Search for no. In step 264, it is determined whether or not a block group with motion is extracted by the search in step 262.

  If the determination in step 264 is negative, the process proceeds to step 276 to determine whether or not the flag is 0. This flag is initially set to 0 when the execution of the radiation moving image capturing / display process (FIG. 9) is started. If the determination in step 276 is affirmative, it can be determined that there is no image portion corresponding to the pulsating organ in the radiographic image to be processed, so the process proceeds to step 286 and the determination result of “no pulsating organ” is output. The pulsating organ search process is terminated.

  When a block group with motion is extracted in the search in step 262, the extracted block group with motion may be a block group corresponding to a pulsating organ, but the patient (subject) 14 moves the body, for example. There is no denying the possibility that it was temporarily extracted due to such reasons. For this reason, when a block group with motion is extracted, the determination at step 264 is affirmed and the routine proceeds to step 266, where the information about the block group with motion extracted by the search at step 262 is used as the frame of the radiation image to be processed. Is stored in the RAM 132 or the like in association with the frame identification information for identifying.

  In the next step 268, on the basis of the information on the block group with motion stored in the RAM 132 or the like, the block group corresponding to the block group with motion extracted this time in at least one radiation image within the past N cycles, It is determined whether or not it has been extracted as a block group with motion in the past processing. In addition, although the said determination determines whether the block group with a motion extracted this time is a block group corresponding to a pulsating organ, the object of determination is made into "at least 1 radiation image within the past N period". This is because pulsating organs such as the heart and the lungs are stationary for a very short time between the expansion phase and the contraction phase.

  If the determination in step 268 is negative, it can be determined that the block group with movement extracted this time is likely to be temporarily extracted by the patient (subject) 14 moving his body, etc. The process proceeds to step 276. On the other hand, if the determination in step 268 is affirmed, the block group with motion extracted this time corresponds to a pulsating organ because the corresponding block group is extracted as the block group with motion even within the past N cycles. It can be judged that the possibility of being a block group is very high. Therefore, the process proceeds to step 270, and the determination result of “there is a pulsating organ” is output. In step 272, 1 is set in the flag. In step 274, 0 is substituted into the variable m, and the pulsating organ search process is terminated.

  Also, once the flag is set to 0 in step 272 above, if the determination in step 264 or step 268 is denied, the determination in step 276 is denied and the process proceeds to step 278, and the variable m is set to 1. Increment. In the next step 280, it is determined whether or not the variable m is equal to or greater than the threshold value M. When this determination is negative, the process proceeds to step 282, the determination result of “having pulsating organ” is output, and the pulsating organ search process is ended.

  As a result, the determination result of “there is a pulsating organ” is output until the determination of step 264 or step 268 is negative until M cycles continue, and before the variable m reaches the threshold value M, step 268 is performed. If the determination is positive, the value of the variable m returns to 0. As described above, in the pulsating organ search processing according to the present embodiment, since the switching of the determination result to be output has hysteresis, the determination result of the pulsating organ search processing is frequently switched, so that the radiation exposure condition Is prevented from switching frequently. If the determination in step 264 or step 268 is negative for M cycles, the determination in step 280 is affirmed, the flag is returned to 0 in step 284, and the determination result to be output is “pulsation organ present” in step 286. And the pulsating organ search process is terminated.

  Next, another configuration of the radiation detector built in the electronic cassette 20 will be described with reference to FIG. A radiation detector 300 shown in FIG. 13 is configured to detect radiation by an indirect conversion method in which irradiated radiation is once converted into light and then converted into electric charge, and a light detection unit (TFT active) is arranged along the radiation arrival direction. (Matrix substrate) 306 and scintillator 302 are arranged in this order. The radiation detector 300 is an example of the radiation detection unit according to claim 11, the light detection unit 306 is the light detection unit according to claim 11, and the scintillator 302 is an example of the light emission unit according to claim 11. is there.

The scintillator 302 of the radiation detector 300 passes through the body of the patient (subject) 14 and is irradiated onto the irradiation surface 32 of the housing 30, and passes through the top plate of the housing 30 and the photodetector (TFT substrate) 306. Absorbs the irradiated radiation X and emits light. The emission wavelength range of the scintillator 302 is preferably a visible light range (wavelength 360 nm to 830 nm), and in order to enable the radiation detector 300 to capture a monochrome radiation image, it includes a green wavelength range. Is more preferable. In general, phosphors applied to the scintillator include, for example, CsI (Tl) (cesium iodide added with thallium), CsI (Na) (sodium-activated cesium iodide), GOS (Gd ₂ O ₂ S: Tb), and the like. However, when imaging using X-rays as radiation, those containing cesium iodide (CsI) are preferable, and CsI (Tl) having an emission spectrum of 420 nm to 600 nm at the time of X-ray irradiation. It is particularly preferable to use Note that the emission peak wavelength of CsI (Tl) in the visible light region is 565 nm.

  Further, in the present embodiment, as shown in FIG. 14 as an example, the scintillator 302 is formed with a columnar crystal region composed of columnar crystals 302A on the radiation incident / light emission side (light detection unit 306 side). A non-columnar crystal region composed of a non-columnar crystal 302B is formed on the side opposite to the incident side. A material containing CsI is used as the scintillator 302, and the material is vapor-deposited on the vapor deposition substrate 304. A scintillator 302 having a non-columnar crystal region is obtained. Note that a material having high heat resistance is desirable for the vapor deposition substrate 304. For example, aluminum is preferable from the viewpoint of low cost. In the scintillator 302 according to this embodiment, the average diameter of the columnar crystals 302A is approximately uniform along the longitudinal direction of the columnar crystals 302A. Thus, the scintillator 302 is an example of a light emitting unit according to claim 12 in more detail.

  As described above, the scintillator 302 has a structure in which a columnar crystal region and a non-columnar crystal region are formed, and a columnar crystal region composed of the columnar crystal 302A from which high-efficiency light emission is obtained is disposed on the light detection unit 306 side. Thus, the light generated by the scintillator 302 travels through the columnar crystal 302A and is emitted to the light detection unit 306, and the diffusion of the light emitted toward the light detection unit 306 is suppressed, so that the electronic cassette 20 detects the light. The reduction in the sharpness of the radiographic image is suppressed. Further, the light reaching the deep part (non-columnar crystal region) of the scintillator 302 is also reflected by the non-columnar crystal 302B toward the light detection unit 306, so that the amount of light incident on the light detection unit 306 (in the scintillator 302). The detection efficiency of the emitted light is improved.

  When the thickness of the columnar crystal region located on the radiation incident side of the scintillator 302 is t1, and the thickness of the non-columnar crystal region located on the vapor deposition substrate 304 side of the scintillator 302 is t2, t1 and t2 have the following relationship: It is preferable to satisfy the formula.

0.01 ≦ (t2 / t1) ≦ 0.25
When the thickness t1 of the columnar crystal region and the thickness t2 of the non-columnar crystal region satisfy the above relational expression, a region that has high luminous efficiency and prevents light diffusion (columnar crystal region), and a region that reflects light (noncolumnar) The ratio of the crystal region) along the thickness direction of the scintillator 302 becomes a suitable range, and the light emission efficiency of the scintillator 302, the detection efficiency of light emitted by the scintillator 302, and the resolution of the radiation image are improved. If the thickness t2 of the non-columnar crystal region is too thick, the region with low luminous efficiency increases and the sensitivity of the electronic cassette 20 is lowered. Therefore, (t2 / t1) is more preferably 0.02 or more and 0.1 or less. .

  The scintillator 302 has a structure in which a columnar crystal region and a non-columnar crystal region are continuously formed. For example, instead of the non-columnar crystal region, a light reflection layer made of aluminum or the like is provided, and only the columnar crystal region is provided. May be configured, or other configurations may be employed.

  The light detection unit 306 of the radiation detector 300 detects light emitted from the light emission side of the scintillator 302, and as shown in FIG. 13, photoelectric conversion including a photodiode (PD: PhotoDiode) or the like. The pixel portion 314 including the portion 308, the TFT 310, and the storage capacitor 312 has a flat plate shape and a rectangular outer shape in plan view, like the TFT active matrix substrate 94 of the radiation detector 36 shown in FIG. A plurality of TFT active matrix substrates (hereinafter referred to as “TFT substrates”) formed in a matrix on the substrate 316 are configured.

  In the present embodiment, the photodetector (TFT substrate) 306 is disposed on the radiation irradiation surface side of the scintillator 302. However, the light emitting unit (scintillator 302) and the light detection unit (light detection unit 306) are arranged in this way. A method of arranging in such a positional relationship is referred to as a “surface reading method (ISS: Irradiation Side Sampling)” (configuration corresponding to the invention of claim 11). Since the scintillator emits light more strongly on the radiation incident side, the surface reading method (ISS) in which the light detection means (light detection unit 306) is arranged on the radiation incidence side of the scintillator is light detection means (on the side opposite to the radiation incidence side of the scintillator ( Since the light detection means and the light emission position of the scintillator are closer to each other than the “PSS (Penetration Side Sampling)” in which the light detection unit 306) is arranged, the resolution of the radiographic image obtained by imaging is high, and the light Increasing the amount of light received by the detection means (light detection unit 306) results in an improvement in the sensitivity of the radiographic imaging device (electronic cassette).

The photoelectric conversion unit 308 is configured such that a photoelectric conversion film 308C that absorbs light emitted from the scintillator 302 and generates electric charge according to the absorbed light is disposed between the lower electrode 308A and the upper electrode 308B. Yes. Note that the lower electrode 308A is preferably made of a conductive material having a high light transmittance with respect to light having the emission wavelength of the scintillator 302 because light emitted from the scintillator 302 needs to enter the photoelectric conversion film 308C. Specifically, it is preferable to use a transparent conductive oxide (TCO) having a high transmittance for visible light and a small resistance value. Although a metal thin film such as Au can be used as the lower electrode 308A, the TCO is preferable because it tends to increase the resistance value when obtaining a light transmittance of 90% or more. For example, ITO, IZO, AZO, FTO, SnO ₂ , TiO ₂ , ZnO ₂ or the like is preferably used, and ITO is most preferable from the viewpoint of process simplicity, low resistance, and transparency. Note that the lower electrode 308A may have a single configuration common to all pixel portions, or may be divided for each pixel portion.

  The photoelectric conversion film 308 </ b> C absorbs light emitted from the scintillator 302 and generates a charge corresponding to the absorbed light. The material constituting the photoelectric conversion film 308C may be any material that absorbs light and generates electric charge. For example, amorphous silicon, an organic photoelectric conversion material, or the like can be used. In the case where the photoelectric conversion film 308C is made of amorphous silicon, light emitted from the scintillator 302 can be absorbed over a wide wavelength range. However, it is necessary to perform vapor deposition for forming the photoelectric conversion film 308C made of amorphous silicon. If the insulating substrate 316 is made of a synthetic resin, the heat resistance of the insulating substrate 316 may be insufficient.

  On the other hand, when the photoelectric conversion film 308C is made of a material containing an organic photoelectric conversion material, an absorption spectrum showing high absorption mainly in the visible light region is obtained, and light other than light emitted from the scintillator 302 by the photoelectric conversion film 308C is obtained. Since almost no electromagnetic wave is absorbed, noise generated by absorption of radiation such as X-rays and γ-rays by the photoelectric conversion film 308C can be suppressed. In addition, the photoelectric conversion film 308C made of an organic photoelectric conversion material can be formed by attaching an organic photoelectric conversion material on the object to be formed using a droplet discharge head such as an inkjet head. Heat resistance is not required. For this reason, in the radiation detector 300, the photoelectric conversion film 308C of the photoelectric conversion unit 308 is made of an organic photoelectric conversion material.

  When the photoelectric conversion film 308C is made of an organic photoelectric conversion material, radiation is hardly absorbed by the photoelectric conversion film 308C. Therefore, in the surface reading method (ISS) in which the light detection unit 306 is disposed so that the radiation is transmitted, light detection is performed. Attenuation of radiation due to transmission through the portion 306 can be suppressed, and a decrease in sensitivity to radiation can be suppressed. Therefore, it is particularly suitable for the surface reading method (ISS) to configure the photoelectric conversion film 308C with an organic photoelectric conversion material.

  The organic photoelectric conversion material constituting the photoelectric conversion film 308 </ b> C preferably has an absorption peak wavelength closer to the emission peak wavelength of the scintillator 302 in order to absorb light emitted from the scintillator 302 most efficiently. Ideally, the absorption peak wavelength of the organic photoelectric conversion material matches the emission peak wavelength of the scintillator 302, but if the difference between the two is small, the light emitted from the scintillator 302 can be sufficiently absorbed. . Specifically, the difference between the absorption peak wavelength of the organic photoelectric conversion material and the emission peak wavelength with respect to the radiation of the scintillator 302 is preferably within 10 nm, and more preferably within 5 nm.

  Examples of organic photoelectric conversion materials that can satisfy such conditions include quinacridone-based organic compounds and phthalocyanine-based organic compounds. For example, since the absorption peak wavelength of quinacridone in the visible region is 560 nm, if quinacridone is used as the organic photoelectric conversion material and CsI (Tl) is used as the material of the scintillator 302, the difference between the peak wavelengths can be within 5 nm. Thus, the amount of charge generated in the photoelectric conversion film 308C can be substantially maximized.

  The photoelectric conversion film 308C applicable to the radiation image capturing apparatus will be specifically described. The electromagnetic wave absorption / photoelectric conversion site in the radiographic apparatus is an organic layer including electrodes 308A and 308B and a photoelectric conversion film 308C sandwiched between the electrodes 308A and 308B. More specifically, this organic layer is a part that absorbs electromagnetic waves, a photoelectric conversion part, an electron transport part, a hole transport part, an electron blocking part, a hole blocking part, a crystallization preventing part, an electrode, and an interlayer contact. It can be formed by stacking or mixing improved parts.

  The organic layer preferably contains an organic p-type compound or an organic n-type compound. An organic p-type semiconductor (compound) is a donor organic semiconductor (compound) mainly represented by a hole transporting organic compound, and is an organic compound having a property of easily donating electrons. More specifically, an organic compound having a smaller ionization potential when two organic materials are used in contact with each other. Accordingly, any organic compound having an electron donating property can be used as the donor organic compound. The organic n-type semiconductor (compound) is an acceptor organic semiconductor (compound) mainly represented by an electron transporting organic compound, and is an organic compound having a property of easily accepting electrons. More specifically, the organic compound having the higher electron affinity when two organic compounds are used in contact with each other. Therefore, any organic compound can be used as the acceptor organic compound as long as it is an organic compound having an electron accepting property.

  The materials applicable as the organic p-type semiconductor and the organic n-type semiconductor and the configuration of the photoelectric conversion film 308C are described in detail in Japanese Patent Application Laid-Open No. 2009-32854, and thus the description thereof is omitted. Note that the photoelectric conversion film 308C may further contain fullerenes or carbon nanotubes.

  The photoelectric conversion unit 308 only needs to include at least the electrode pairs 308A and 308B and the photoelectric conversion film 308C, but at least one of an electron blocking film and a hole blocking film is provided to suppress an increase in dark current. It is preferable to provide both.

  The electron blocking film can be provided between the upper electrode 308B and the photoelectric conversion film 308C. When a bias voltage is applied between the upper electrode 308B and the lower electrode 308A, the electron blocking film is applied from the upper electrode 308B to the photoelectric conversion film 308C. An increase in dark current due to injection of electrons can be suppressed. An electron donating organic material can be used for the electron blocking film. The material actually used for the electron blocking film may be selected according to the material of the adjacent electrode and the material of the adjacent photoelectric conversion film 308C, and the electron affinity is 1.3 eV or more from the work function (Wf) of the adjacent electrode material. A material having a large (Ea) and an Ip equivalent to or smaller than the ionization potential (Ip) of the material of the adjacent photoelectric conversion film 308C is preferable. Since the material applicable as the electron donating organic material is described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted.

  The thickness of the electron blocking film is preferably 10 nm or more and 200 nm or less, more preferably 30 nm or more and 150 nm or less, particularly preferably, in order to surely exhibit the dark current suppressing effect and prevent a decrease in the photoelectric conversion efficiency of the photoelectric conversion unit 308. It is 50 nm or more and 100 nm or less.

  The hole blocking film can be provided between the photoelectric conversion film 308C and the lower electrode 308A, and when a bias voltage is applied between the upper electrode 308B and the lower electrode 308A, the lower electrode 308A to the photoelectric conversion film 308C. It is possible to suppress the increase of dark current due to injection of holes into the substrate. An electron-accepting organic material can be used for the hole blocking film. The material actually used for the hole blocking film may be selected according to the material of the adjacent electrode, the material of the adjacent photoelectric conversion film 308C, etc., and the ionization is 1.3 eV or more from the work function (Wf) of the adjacent electrode material. A material having a large potential (Ip) and an Ea equivalent to or larger than the electron affinity (Ea) of the material of the adjacent photoelectric conversion film 308C is preferable. Since the material applicable as the electron-accepting organic material is described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted.

  The thickness of the hole blocking film is preferably 10 nm or more and 200 nm or less, more preferably 30 nm or more and 150 nm or less, particularly preferably, in order to reliably exhibit the dark current suppressing effect and prevent a decrease in the photoelectric conversion efficiency of the photoelectric conversion unit 308. Is from 50 nm to 100 nm.

  When the bias voltage is set so that holes move to the lower electrode 308A and electrons move to the upper electrode 308B among the charges generated in the photoelectric conversion film 308C, the electron blocking film and the hole blocking film are used. It is sufficient to reverse the position of. Moreover, it is not essential to provide both the electron blocking film and the hole blocking film, and if any of them is provided, a certain degree of dark current suppressing effect can be obtained.

  In the TFT 310, a gate electrode, a gate insulating film, and an active layer (channel layer) are stacked, and a source electrode and a drain electrode are formed on the active layer at a predetermined interval. The active layer can be formed of any one of, for example, amorphous silicon, amorphous oxide, organic semiconductor material, carbon nanotube, etc., but the material capable of forming the active layer is not limited to these. .

As an amorphous oxide capable of forming an active layer, for example, an oxide containing at least one of In, Ga, and Zn (for example, an In-O system) is preferable, and at least one of In, Ga, and Zn is used. Oxides containing two (eg, In—Zn—O, In—Ga—O, and Ga—Zn—O) are more preferable, and oxides including In, Ga, and Zn are particularly preferable. As the In—Ga—Zn—O-based amorphous oxide, an amorphous oxide whose composition in a crystalline state is represented by InGaO ₃ (ZnO) _m (m is a natural number less than 6) is preferable, and InGaZnO is particularly preferable. ₄ is more preferable. Note that the amorphous oxide capable of forming the active layer is not limited to these.

  Examples of the organic semiconductor material capable of forming an active layer include, but are not limited to, phthalocyanine compounds, pentacene, vanadyl phthalocyanine, and the like. In addition, about the structure of a phthalocyanine compound, since it demonstrates in detail by Unexamined-Japanese-Patent No. 2009-212389, description is abbreviate | omitted.

  If the active layer of the TFT 310 is formed of any one of amorphous oxide, organic semiconductor material, carbon nanotube, etc., radiation such as X-rays is not absorbed, or even if it is absorbed, a very small amount remains. The superimposition of noise on the signal can be effectively suppressed.

  Further, when the active layer is formed of carbon nanotubes, the switching speed of the TFT 310 can be increased, and the degree of light absorption in the visible light region of the TFT 310 can be reduced. In addition, when the active layer is formed of carbon nanotubes, the performance of the TFT 310 is remarkably deteriorated just by mixing a very small amount of metallic impurities into the active layer. Therefore, it must be used for forming the active layer.

  Note that since the film formed of the organic photoelectric conversion material and the film formed of the organic semiconductor material have sufficient flexibility, the photoelectric conversion film 308C formed of the organic photoelectric conversion material and the active layer are made of organic If the TFT 310 formed of a semiconductor material is combined, it is not always necessary to increase the rigidity of the light detection unit 306 to which the weight of the body of the patient (subject) 14 is applied as a load. For this reason, in the radiation detector 300, the active layer of the TFT 310 is formed of an organic semiconductor material.

  The insulating substrate 316 may be any substrate as long as it has optical transparency and low radiation absorption. Here, both the amorphous oxide constituting the active layer of the TFT 310 and the organic photoelectric conversion material constituting the photoelectric conversion film 308C of the photoelectric conversion portion 308 can be formed at a low temperature. Accordingly, the insulating substrate 316 is not limited to a highly heat-resistant substrate such as a semiconductor substrate, a quartz substrate, and a glass substrate, and a flexible substrate made of synthetic resin, aramid, or bionanofiber can also be used. Specifically, flexible materials such as polyesters such as polyethylene terephthalate, polybutylene phthalate, polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin, poly (chlorotrifluoroethylene), etc. A conductive substrate can be used. By using such a flexible substrate made of synthetic resin, it is possible to reduce the weight, which is advantageous for carrying around, for example. Note that the insulating substrate 316 includes an insulating layer for ensuring insulation, a gas barrier layer for preventing permeation of moisture and oxygen, an undercoat layer for improving flatness or adhesion to electrodes, and the like. May be provided.

  Since aramid can be applied at a high temperature process of 200 ° C. or more, the transparent electrode material can be cured at a high temperature to reduce the resistance, and can be applied to automatic mounting of a driver IC including a solder reflow process. Moreover, since aramid has a thermal expansion coefficient close to that of ITO (indium tin oxide) or a glass substrate, there is little warping after manufacturing and it is difficult to break. In addition, aramid can make a substrate thinner than a glass substrate or the like. Note that the insulating substrate 316 may be formed by stacking an ultrathin glass substrate and aramid.

  The bionanofiber is a composite of a cellulose microfibril bundle (bacterial cellulose) produced by bacteria (Acetobacter Xylinum) and a transparent resin. The cellulose microfibril bundle has a width of 50 nm and a size of 1/10 of the visible light wavelength, and has high strength, high elasticity, and low thermal expansion. By impregnating and curing a transparent resin such as an acrylic resin or an epoxy resin in bacterial cellulose, a bio-nanofiber having a light transmittance of about 90% at a wavelength of 500 nm can be obtained while containing 60 to 70% of the fiber. Bionanofiber has a low coefficient of thermal expansion (3-7ppm) comparable to silicon crystals, and is as strong as steel (460MPa), highly elastic (30GPa), and flexible, compared to glass substrates, etc. The insulating substrate 316 can be thinned.

  When a glass substrate is used as the insulating substrate 316, the total thickness of the photodetector (TFT substrate) 306 is, for example, about 0.7 mm. However, in the radiation detector 300, the electronic cassette 20 is also considered thin. As the insulating substrate 316, a thin substrate made of a light-transmitting synthetic resin is used. Thereby, the thickness of the entire photodetector (TFT substrate) 306 can be reduced to, for example, about 0.1 mm, and the photodetector (TFT substrate) 306 can be made flexible. Further, by making the photodetector (TFT substrate) 306 flexible, the impact resistance of the radiation detection unit 300 is improved, and the radiation detection unit 300 is also applied when an impact is applied to the housing 30 of the electronic cassette 20. Is difficult to break. In addition, plastic resin, aramid, bio-nanofiber, etc. all absorb little radiation, and when the insulating substrate 316 is formed of these materials, the amount of radiation absorbed by the insulating substrate 316 is also small. Even if the radiation is transmitted through the light detection unit 306 by (ISS), a decrease in sensitivity to radiation can be suppressed.

  Note that it is not essential to use a synthetic resin substrate as the insulating substrate 316 of the electronic cassette 20, and although the thickness of the electronic cassette 20 increases, a substrate made of another material such as a glass substrate is used as the insulating substrate 316. You may make it use as.

  As described above, the radiation detector 300 is a surface reading method (ISS) in which the light detection unit 306 and the scintillator 302 are sequentially arranged along the radiation arrival direction, and the scintillator 302 is made of a material containing CsI. By adopting a configuration in which a columnar crystal region is formed on the light detection unit 306 side, an increase in the amount of light incident on the light detection unit 306 from the scintillator 302 and suppression of diffusion are realized. The photoelectric conversion film 308C of 306 is formed of an organic photoelectric conversion material, the active layer of the TFT 310 is formed of an organic semiconductor material, and a synthetic resin substrate is used as the insulating substrate 316, so that the light detection unit 306 is transmitted. Since the absorption of the radiation irradiated to the scintillator 302 in the light detection unit 306 is suppressed, the radiation detection sensitivity is improved and the radiographic image to be captured is improved in image quality. It can be current.

  The electronic cassette 20 incorporating the radiation detector 300 having the above-described configuration is particularly suitable for capturing a radiation moving image. That is, in the radiographic image capturing, there is a problem of suppressing the radiation exposure dose of the patient (subject) 14, and the required level for the image quality is relatively low. On the other hand, the radiation detector 300 having the above-described configuration has high radiation detection sensitivity and can capture a high-quality radiation image. Therefore, even when the radiation dose is greatly reduced when capturing a radiation moving image, the radiation detector 300 is captured. Therefore, the radiation exposure dose of the patient (subject) 14 can be greatly suppressed by significantly reducing the radiation exposure dose.

  CsI has a characteristic that the sensitivity changes at a rate of change of about 0.3% per 1 ° C. of temperature change (see also FIG. 15A). For this reason, when a radiation detector having a configuration including a scintillator made of CsI, such as the radiation detector 300 described above, is used as a radiation detector built in the electronic cassette 20, the radiation detection sensitivity decreases as the temperature rises. Arise. In particular, when taking a moving image of radiation, the change in radiation detection sensitivity also increases due to the large change in temperature.Accordingly, the image taken at the beginning of the photographing period and the image taken at the end of the photographing period As the density difference increases, there is a possibility that inconveniences such as deterioration of the visibility of the radiation moving image may occur.

  Considering this, for example, a temperature sensor for detecting the temperature of the scintillator is provided, and when the temperature detected by the temperature sensor is equal to or higher than a preset threshold, the photographing mode is set to the irradiation time increase mode, etc. The first control according to the present invention is preferably configured to be performed. In the first control according to the present invention, the time interval of intermittent irradiation of radiation is longer than that in the second control according to the present invention, and the amount of heat generated from the electronic circuit built in the electronic cassette 20 is reduced, so that CsI constituting the scintillator Can be suppressed, and the radiation detection sensitivity can be suppressed from decreasing with an increase in the temperature of CsI. The detection of the scintillator temperature is not limited to directly detecting the temperature of the scintillator itself. For example, the temperature of the scintillator is indirectly detected by detecting the temperature in the housing 30 of the electronic cassette 20. It is also possible to adopt a configuration that does this.

  CsI also has a characteristic that the sensitivity gradually decreases as the cumulative radiation exposure increases (see also FIG. 15B). In addition, although the fall of the sensitivity accompanying the increase in radiation exposure dose is a temporary phenomenon, it will recover if it continues the state which does not irradiate radiation for several hours, However, As a radiation detector built in the electronic cassette 20, as above-mentioned When a radiation detector having a configuration including a scintillator made of CsI, such as the radiation detector 300, is used, if the sensitivity of CsI is significantly reduced, there is a possibility that radiographic imaging may be hindered. .

  In consideration of this, the first control according to the present invention is performed by monitoring the cumulative radiation exposure dose and setting the imaging mode to the irradiation time increase mode when the cumulative radiation exposure dose exceeds a preset threshold value. It is preferable to be configured to perform. Since the first control according to the present invention can reduce the radiation exposure dose as compared with the second control according to the present invention, the usable time of the electronic cassette 20 can be extended.

  FIG. 16 shows still another configuration of the radiation detector. The radiation detector 300 illustrated in FIG. 13 has a configuration in which the light emitted from the scintillator 302 is detected by a single light detection unit 306, but the radiation detector 318 illustrated in FIG. 16 is added to the light detection unit 306. Thus, a light detection unit 320 that detects light emitted from the scintillator 302 is provided on the opposite side of the scintillator 302 with the light detection unit 306 interposed therebetween. In the light detection unit 320, a wiring layer 322 in which wirings are patterned and an insulating layer 324 are sequentially formed, and a plurality of sensor units 326 that detect light emitted from the scintillator 302 and transmitted through the light detection unit 306 are formed thereon. Further, a protective layer 328 is formed above the sensor portion 326. Note that the thickness of the light detection unit 320 is, for example, about 0.05 mm.

  The sensor unit 326 includes an upper electrode 330A and a lower electrode 330B, and a photoelectric conversion film 330C that absorbs light from the scintillator 302 and generates charges is disposed between the upper electrode 330A and the lower electrode 330B. ing. As the sensor unit 326 (photoelectric conversion film 330C), a PIN-type or MIS-type photodiode using amorphous silicon can be applied. However, in the radiation detector 318, the photoelectric conversion film 308C of the photoelectric conversion unit 308 Similarly, the photoelectric conversion film 330C is made of an organic photoelectric conversion material. Accordingly, the photoelectric conversion film 330C can be formed by attaching the organic photoelectric conversion material onto the object to be formed using a droplet discharge head such as an inkjet head, and the insulating substrate 316 has light transmittance. It is possible to use a thin substrate made of a synthetic resin.

  The detection result of the radiation dose by the sensor unit 326 is read out via a signal processing unit (not shown) connected to the electrodes 330A and 330B, for example, detection of radiation irradiation start / end timing to the electronic cassette 20, and electronic cassette This is used for detecting the integrated value of the radiation dose to 20. Since detection (imaging) of a radiographic image is performed by the light detection unit 306, the sensor unit 326 of the light detection unit 320 has a larger arrangement pitch (lower arrangement density) than the pixel unit 314 of the light detection unit 306. In addition, the light receiving region of the single sensor unit 326 may have a size corresponding to several to several hundreds of the pixel units 314 of the light detection unit 306.

  In the above description, the mode in which the radiation irradiation time t or the radiation irradiation period T is changed in two stages depending on whether or not a pulsating organ is present in the radiographic moving image capturing range has been described. For example, as the area ratio of the image portion corresponding to the pulsating organ in the radiation moving image increases, the radiation irradiation time t is continuously increased or the radiation irradiation time t becomes longer. As described above, the value may be switched to any one of the three or more levels of radiation irradiation time t. As for the radiation irradiation period T, for example, as the area ratio of the image portion corresponding to the pulsating organ in the radiation moving image increases, the radiation irradiation period T is continuously shortened or the radiation irradiation period T is shortened. As such, the value may be switched to any one of three or more radiation irradiation period T values.

  In the above, in the pulsating organ search process (FIG. 11), the presence or absence of the pulsating organ is determined by a constant process regardless of the radiation exposure conditions (radiation irradiation period T, radiation irradiation time t, and radiation irradiation dose W). Although the embodiment has been described, the present invention is not limited to this. For example, the search range set for the radiation image of the previous period, the threshold for the magnitude of the motion vector, and the motion according to the radiation exposure conditions At least one of the threshold for the number of blocks to be determined in the presence block group, the value of the number of periods N in the determination in step 268, and the value of the threshold M to be compared with the variable m in the determination in step 280 is changed. It may be. Further, the pulsating organ search process shown in FIG. 11 is an example, and it is also included in the scope of the present invention to determine whether or not a pulsating organ exists in the radiographic moving image capturing range by another process. .

  In the above description, a mode in which a moving image is displayed on the display 136 of the console 24 has been described. However, the present invention is not limited to this, and a display is provided in the electronic cassette 20. A moving image may be displayed on the display on the cassette 20.

  Further, in the above description, the first moving device 50 that moves the electronic cassette 20 and the second moving device 78 that moves the radiation irradiating device 18 have been described as moving means according to claim 6, but the moving means is the bed 16. The patient (subject) 14 may be moved by moving a part of (for example, only the mounting table 16A) or the whole. The first moving device 50 and the second moving device 78 relatively move the radiation irradiation device 18 and the electronic cassette 20 and the patient (subject) 14 only in the longitudinal direction of the mounting table 16A (perform a uniaxial movement). However, the moving means described in claim 6 is not limited to the above, and the radiation irradiation device 18, the electronic cassette 20, and the patient (subject) 14 can be relatively moved in the width direction of the mounting table 16A. It may be a configuration that performs biaxial movement.

  Moreover, although the aspect which applied this invention to imaging | photography of the radiation moving image at the time of implementing IVR was demonstrated above, this invention is not limited to this, In scenes other than implementation of IVR in a medical field It can also be applied to radiographic image capturing.

  In the above description, the human subject (patient 14) is described as an example of the subject described in claims 2, 6, and 8. However, the subject is not limited to this, and the subject may be a living organism other than a human being. It may be non-living and can be applied to radiographic image capture of any subject that has a possibility that an object whose movement speed is a predetermined value or more (this object is not limited to an organ) may fall within the imaging range. .

DESCRIPTION OF SYMBOLS 10 Radiation imaging system 18 Radiation irradiation apparatus 20 Electronic cassette 24 Console 136 Display

Claims (12)

An irradiation means for intermittently emitting radiation;
Radiation detecting means for detecting radiation at a timing synchronized with intermittent irradiation of radiation by the irradiation means;
Display control means for displaying the detection result of radiation by the radiation detection means on the display means as a moving image;
Determining means for determining whether or not an object having a speed of movement equal to or greater than a predetermined value is present in a radiation detection range by the radiation detecting means;
When there is an object whose movement speed is equal to or higher than the predetermined value in the radiation detection range, the object is faster than the case where an object whose movement speed is higher than the predetermined value is not present in the radiation detection range. An imaging control means for performing a first control for increasing the irradiation time of the radiation per cycle in the intermittent irradiation of radiation by the irradiation means, or a second control for shortening the time interval of the intermittent irradiation of radiation by the irradiation means;
A radiographic imaging apparatus including: A calculation means for calculating the cumulative radiation exposure amount of the subject;
The imaging control means performs the first control when the cumulative radiation exposure amount of the subject calculated by the calculation means exceeds a predetermined value, and the speed of movement within the radiation detection range is equal to or higher than the predetermined value. The radiographic imaging apparatus according to claim 1, wherein control is performed such that a dose of radiation irradiated by the irradiation unit is lower than when no object exists. A selecting means for selecting whether to perform the first control or the second control;
The imaging control means is selected in advance through the selection means of the first control and the second control when there is an object whose movement speed is greater than or equal to the predetermined value within the radiation detection range. The radiographic imaging apparatus according to claim 1, wherein the control is performed.   The imaging control means, when performing the first control, the radiation dose irradiated by the irradiating means, compared to the case where there is no object whose movement speed is not less than the predetermined value within the radiation detection range. The radiographic image capturing apparatus according to claim 1, wherein the radiographic image capturing apparatus is controlled so as to be reduced. A setting means for setting a radiation dose;
The radiation according to any one of claims 1 to 3, wherein the imaging control unit changes the dose of radiation irradiated by the irradiation unit in accordance with the radiation dose set through the setting unit. Image shooting device. A moving means for moving the irradiating means and the radiation detecting means relative to the subject;
The imaging control means responds to a change in the position of the distal end portion of the insertion member so that an image portion corresponding to the distal end portion of the insertion member inserted into the body of the subject is located within a predetermined region in the moving image. The radiographic imaging apparatus according to any one of claims 1 to 5, wherein the moving unit relatively moves the irradiation unit, the radiation detection unit, and the subject.   The determination unit sequentially acquires a single frame image representing a radiation detection result by the radiation detection unit, and each of the images when the image is divided into a plurality of blocks based on a plurality of continuous frame images. A motion vector is calculated for each block, and it is searched whether or not there is a block group with motion including a plurality of adjacent blocks each having a magnitude of the calculated motion vector equal to or greater than a predetermined value. When a group is extracted, it is determined whether or not the corresponding block group has been extracted from the images of frames within a predetermined number in the past as a block group with motion, and the corresponding block group is determined as a block group with motion. If extracted, the block group with motion extracted this time is determined as a block group corresponding to an organ whose motion speed is a predetermined value or more. And determining whether or not there is an organ having a motion speed of a predetermined value or more as an object having a motion speed of a predetermined value or more within the radiation detection range by the radiation detection means. The radiographic imaging apparatus of any one of Claims 1-6. An irradiation means for intermittently emitting radiation;
Radiation detecting means for detecting radiation at a timing synchronized with intermittent irradiation of radiation by the irradiation means;
Display control means for displaying the detection result of radiation by the radiation detection means on the display means as a moving image;
When an organ whose movement speed is greater than or equal to a predetermined value among the organs of the subject exists within the radiation detection range by the radiation detection means, movement of the organ whose movement speed is equal to or greater than a predetermined value on the moving image Imaging control means for changing the irradiation time of the radiation per cycle in the intermittent irradiation of the radiation by the irradiation means, or the time interval of the intermittent irradiation of the radiation by the irradiation means, so that the discontinuity of the irradiation means decreases,
A radiographic imaging apparatus including:   The radiographic imaging apparatus according to claim 1, wherein the radiation detection unit includes a radiation conversion layer and a switching layer.   The radiographic image capturing apparatus according to any one of claims 1 to 9, wherein the radiation detecting means is a portable radiographic image detecting apparatus that is detachably attached to the radiographic image capturing apparatus.   The radiation detection unit includes a light emitting unit that absorbs emitted radiation and emits light, and a light detection unit that detects light emitted from the light emitting unit as an image, and the light emitting unit is formed by the light detection unit. The radiographic imaging device according to claim 1, which is also arranged downstream of the radiation arrival direction.   The radiographic image capturing apparatus according to claim 11, wherein the light emitting portion is made of a material containing CsI, and a columnar crystal structure portion is formed.

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