JP5623890B2 - Radiation control device and radiographic imaging system - Google Patents

Description

  The present invention relates to a radiation control apparatus and a radiation image capturing system, and more particularly, to a radiation control apparatus and a radiation image capturing system that perform control related to radiation when capturing a moving image of a radiation image.

  A catheter with various devices attached to the tip is inserted into the patient's body, and the state of the patient's body is observed in real time with a radiographic image displayed on the monitor, while the tip of the catheter reaches the lesion, and the catheter IVR (Interventional Radiology), which treats patients by operating them outside the body, is rapidly spreading.

  By the way, when performing IVR, since the surgeon performs treatment while observing the radiation image displayed on the monitor, the radiation dose to the patient increases as the treatment time becomes longer. There is.

  Therefore, as a technique that can be applied to solve this problem, Patent Document 1 discloses an X-ray generation unit that irradiates a subject with X-rays, and an X-ray generation unit that irradiates the subject and transmits the subject. X-ray detection means for detecting X-rays, image data generation means for generating X-ray image data for the subject based on the X-rays detected by the X-ray detection means, and the generated X-ray image data Display means for displaying, dose detection means for detecting the radiation dose of X-rays emitted from the X-ray generation means, and the irradiation dose on the subject based on the radiation dose detected by the dose detection means An irradiation dose calculating means for calculating, an irradiation dose comparing means for comparing the irradiation dose calculated by the irradiation dose calculating means with a preset allowable irradiation dose, and the irradiation dose ratio X-ray diagnostic apparatus is disclosed which is characterized in that and a dose control means for controlling the radiation dose of X-rays by the X-ray generating means on the basis of the comparison result obtained by the means.

  Patent Document 2 discloses an imaging unit that captures an image of a subject with radiation and acquires image information of the subject, a type of a source of image information obtained by the imaging unit, an attribute of the subject, and the subject. A setting means for setting information on the imaging region, an aperture amount determining means for determining the amount of radiation aperture based on the information set by the setting means, and an aperture amount determined by the aperture amount determining means. On the basis of this, an imaging apparatus comprising an aperture control means for controlling the aperture of the radiation is disclosed.

  Patent Document 3 includes an X-ray generator that intermittently irradiates a subject with X-rays, and an X-ray detector that acquires image data corresponding to the incident dose of X-rays that have passed through the subject. An X-ray fluoroscopic apparatus, which controls the irradiation dose of X-rays to a subject and combines irradiation with the irradiation dose becoming a normal dose and irradiation with the irradiation dose being a lower dose than the normal dose There has been disclosed an X-ray fluoroscopic apparatus characterized by comprising dose control means for allowing repeated irradiation patterns.

  Further, in Patent Document 4, an allowable residual exposure is calculated based on a difference between an estimation unit that estimates the cumulative exposure dose of X-rays irradiated to an object, an allowable maximum exposure dose, and the cumulative exposure dose. Allowable residual exposure amount calculating means, X-ray irradiation allowable time calculating means for calculating an X-ray irradiation allowable time based on a difference between a predetermined X-ray irradiation scheduled time and an actual irradiation time of X-rays irradiated to the object. X-ray irradiation reference amount calculating means for calculating an X-ray irradiation reference amount per unit time that is a reference for X-ray irradiation based on the allowable residual exposure amount and the X-ray irradiation allowable time, and the X-ray X-ray imaging comprising: a control unit that sets an X-ray irradiation amount per unit time within the allowable X-ray irradiation time based on an irradiation reference amount and controls X-ray irradiation on the object. An apparatus is disclosed.

JP 2005-198762 A JP 2001-17416 A JP 2008-119195 A JP 2008-272381 A

  However, although the techniques disclosed in Patent Literature 1 to Patent Literature 4 can reduce the exposure dose to the patient, the radiation dose is also reduced for the region of interest. There was a problem of lowering.

  The present invention has been made in order to solve the above-described problems, and a radiation control device and a radiographic imaging capable of suppressing an exposure dose to a subject while preventing a deterioration in image quality of a radiographic image in a region of interest. The purpose is to provide a system.

  In order to achieve the above object, the radiation control apparatus according to claim 1 is configured to calculate a cumulative exposure dose from a point of time when radiation treatment applied to a subject from a radiation source for moving image radiography is started. A calculating means for calculating, a limiting means for limiting the exposure dose to the radiation field excluding the region of interest of radiation from the radiation source, and whether the cumulative exposure dose calculated by the calculation means reaches a predetermined exposure dose Determining means for determining whether or not, and a control means for controlling the limiting means so as to apply the restriction when the determining means determines that the cumulative exposure amount reaches a predetermined exposure amount. I have.

  According to the radiation control apparatus according to claim 1, the cumulative exposure dose from the time when the radiation treatment to be applied to the subject from the radiation source is started for calculating a radiographic image by the calculation means. On the other hand, the limiting means limits the exposure amount to the irradiation field excluding the region of interest of the radiation by the radiation source.

  Here, in the present invention, it is determined whether or not the cumulative exposure calculated by the calculation means reaches a predetermined exposure dose by the determination means, and the control means determines the cumulative exposure dose by the determination means. When it is determined that the predetermined exposure dose is reached, the limiting means is controlled to add the limit.

  As described above, according to the radiation control apparatus of the first aspect, the cumulative exposure dose from the time when the radiation treatment applied to the subject from the radiation source is started in advance for capturing a radiographic image. When it is determined that the exposure dose has been reached, control is performed so as to limit the exposure dose to the irradiation field excluding the region of interest of radiation from the radiation source, so that the image quality of the radiation image in the region of interest is degraded. It is possible to suppress the exposure dose to the subject while preventing this.

  In the present invention, as in the invention described in claim 2, the cumulative exposure dose to the irradiation field from the time when the calculation means starts the treatment as the cumulative exposure dose to the time when the moving image shooting ends. May be calculated. Thereby, the cumulative exposure amount up to the time point when the moving image shooting in the irradiation field excluding the region of interest is completed can be made equal to or less than the predetermined exposure amount.

  Further, according to the present invention, as in the invention described in claim 3, the restriction means is provided between the radiation source and the subject, and passes a part of radiation emitted from the radiation source. And the control unit controls the throttle unit to apply the restriction by changing the area of the aperture region of the throttle unit. May be. Thereby, as a result of making the region of the irradiation field excluding the region of interest variable, the convenience can be further improved.

  In particular, the invention described in claim 3 is configured such that, as in the invention described in claim 4, the diaphragm portion is configured such that the transmitted dose of radiation decreases with increasing distance from the peripheral portion of the opening region. Good. Thereby, the radiographic image in the irradiation field excluding the region of interest can also be observed.

  Further, according to the present invention, as in the invention described in claim 5, the calculation means may calculate the cumulative exposure dose for each of the divided areas defined as a predetermined unit area in the irradiation field. Thereby, it is possible to limit the exposure dose to the subject more finely than in the case where the cumulative exposure dose is calculated for the entire irradiation field.

  Further, in the present invention, as in the invention described in claim 6, the control means may perform the control by following a region of interest that changes with the passage of time. Thereby, the convenience can be improved more.

  In particular, the invention described in claim 6 further includes specifying means for specifying the position of a predetermined part of the medical instrument inserted into the subject as in the invention described in claim 7. The control unit may perform the control using the position specified by the specifying unit as the region of interest. Thereby, it is not necessary to set the region of interest in advance, and the convenience can be further improved.

  Further, according to a seventh aspect of the present invention, as in the eighth aspect of the present invention, the specifying means is provided in image recognition based on image information obtained by the moving image photographing, in the predetermined part. The position of the predetermined part may be specified by at least one of the IC tag and the magnetic body provided in the part. Thereby, when the specifying means specifies the position by the image recognition, it is not necessary to provide a member for the specification, so that the present invention can be realized at a low cost. When the position is specified by at least one of the tag and the magnetic body, the position can be specified more reliably than in the case of specifying by the image recognition.

  Note that the IC tag is sometimes referred to as an RFID tag, an ID tag, a wireless tag, or the like. In this specification, these tags are collectively referred to as an IC tag.

  On the other hand, in order to achieve the above object, a radiographic imaging system according to claim 9 is controlled by the radiation control apparatus according to any one of claims 1 to 8 and the radiation control apparatus. A radiographic image capturing apparatus that captures a moving image of a radiographic image indicated by the radiation emitted from the radiation source that emits the radiation to be transmitted through the subject.

  A radiographic imaging system according to a thirteenth aspect includes a radiation control apparatus according to any one of the first to eighth aspects, and a radiation source that emits radiation to be controlled by the radiation control apparatus. , Including.

  Furthermore, a radiographic imaging system according to a fourteenth aspect includes a radiation control apparatus according to any one of the first to eighth aspects, and a radiation source that emits radiation to be controlled by the radiation control apparatus. A radiation image capturing apparatus for capturing a moving image of a radiation image indicated by radiation that has been emitted and transmitted through a subject, and the radiation source are included.

  Thus, since the invention of Claim 9, Claim 13, and Claim 14 includes the radiation control apparatus of this invention, the fall of the image quality of the radiographic image in a region of interest is prevented like the said radiation control apparatus. However, the exposure dose to the subject can be suppressed.

The invention according to claim 9 is the same as the invention according to claim 10, wherein the radiographic imaging device has a phosphor layer that generates light when irradiated with radiation, and the phosphor layer. comprising a radiation detector of an indirect conversion type that board of photoelectric conversion elements are formed for converting the generated light into an electric charge is formed by laminating, it may be performed for moving image shooting by the radiation detector.

In the tenth aspect of the present invention, the phosphor layer may include CsI as in the case of the eleventh aspect.

The invention according to claim 10 or claim 11 is arranged in the radiographic imaging apparatus so that the radiation is incident from the substrate side, as in the invention according to claim 12. It is preferable.

  According to the radiation control apparatus and the radiographic imaging system of the present invention, the cumulative exposure dose from the start of the radiation treatment applied to the subject from the radiation source for moving image radiography is determined in advance. When it is determined that the exposure dose is reached, control is performed so as to limit the exposure dose to the radiation field excluding the region of interest of radiation from the radiation source, thereby preventing deterioration of the image quality of the radiation image in the region of interest However, the effect that the exposure amount with respect to a subject can be suppressed is acquired.

It is a perspective view which shows the mode of the operating room where the radiographic imaging system which concerns on embodiment was installed. It is a partially broken perspective view which shows the internal structure of the electronic cassette which concerns on embodiment. It is a perspective view which shows the principal part structure of the radiation irradiation apparatus which concerns on embodiment. It is the schematic which shows the mode at the time of implementing IVR which concerns on embodiment. It is a block diagram which shows the structure of the radiographic imaging system which concerns on embodiment. It is the equivalent circuit diagram which paid its attention to 1 pixel part of the radiation detector which concerns on embodiment. It is a schematic diagram which shows an example of a data structure of the exposure amount threshold value information which concerns on embodiment. It is sectional drawing which showed typically the structure of the radiation detector of the indirect conversion system which concerns on embodiment. It is sectional drawing which showed roughly the structure of the TFT substrate which concerns on embodiment. It is a cross-sectional side view for demonstrating a surface reading system and a back surface reading system. It is a flowchart which shows the flow of a process of the radiographic imaging process program which concerns on 1st Embodiment. It is a schematic diagram with which it uses for description regarding calculation of the accumulated exposure dose in the radiographic imaging process program which concerns on embodiment. It is a figure which shows an example of the radiographic image displayed on the display surface of a display by irradiating the whole irradiation surface of the radiation detector which concerns on embodiment. It is a figure which shows an example of the radiographic image displayed on the display surface of a display by irradiating the partial area | region of the irradiation surface of the radiation detector which concerns on embodiment. It is a graph which shows the relationship between the temperature of CsI and GOS, and a sensitivity. It is a graph which shows the relationship between the cumulative exposure amount of CsI, and a sensitivity. It is a flowchart which shows the flow of a process of the radiographic imaging process program which concerns on 2nd Embodiment. It is a perspective view which shows the principal part structure of the radiation irradiation apparatus which concerns on other embodiment. It is a perspective view which shows the principal part structure of the radiation irradiation apparatus which concerns on other embodiment. It is a perspective view which shows the principal part structure of the radiation irradiation apparatus which concerns on other embodiment. It is a perspective view which shows the principal part structure of the radiation irradiation apparatus which concerns on other embodiment. It is a top view which shows the principal part structure of the aperture | diaphragm | squeeze part which concerns on other embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[First Embodiment]
First, the configuration of a radiographic image capturing system (hereinafter also simply referred to as “imaging system”) 10 according to the present embodiment will be described with reference to FIG.

  As shown in the figure, an imaging system 10 according to the present embodiment captures a radiographic image by an operation of a doctor 12 or a radiographer. The imaging system 10 detects the bed 16 on which the patient 14 lies, the radiation irradiation device 18 that irradiates the patient 14 with radiation X having a radiation dose according to preset imaging conditions, and the radiation X that has passed through the patient 14. Then, radiographic image information (hereinafter, also simply referred to as “image information”) indicating a radiographic image corresponding to the detected radiation dose is generated, and the image information is stored in a predetermined storage area to perform imaging. A portable imaging device (hereinafter also referred to as “electronic cassette”) 20, a support member 22 that is provided on the bed 16 and cantilever-supports the electronic cassette 20 on the side of the bed 16 where the patient 14 lies, and a radiation irradiation device 18. And a console 26 for controlling the electronic cassette 20.

  The bed 16 is made of a material that transmits the radiation X, and includes a substantially rectangular flat plate-shaped mounting table 16A on which the patient 14 lies, and leg portions 16B that are provided at four corners of the mounting table 16A and support the mounting table 16A. ing.

  Here, the radiation irradiation device 18 is arranged on the back side of the mounting table 16A so that the patient 14 on the mounting table 16A is irradiated with the radiation X from the back side of the mounting table 16A (the side opposite to the side on which the patient 14 lies). Yes.

  On the other hand, the electronic cassette 20 according to the present embodiment includes a display 28 on the back surface on which a captured radiation image is displayed, and is irradiated from the radiation irradiation device 18 with the display surface 28A of the display 28 facing upward. The radiation X is arranged on the front side of the mounting table 16A (side on which the patient 14 lies) so that the radiation X passes through the mounting table 16A and the patient 14 and is detected by a radiation detector 36 described later.

  A support member 22 is provided on the surface of the mounting table 16A on the side on which the patient 14 lies. The support member 22 is bent in a substantially L shape, a base end portion is fixed to the mounting table 16A, and an electronic cassette 20 is detachably attached to the distal end portion.

  FIG. 2 shows an internal configuration of the electronic cassette 20 according to the present exemplary embodiment.

  As shown in the figure, the electronic cassette 20 includes a substantially rectangular flat plate-shaped casing 30 made of a material that transmits the radiation X. When the electronic cassette 20 is used in an operating room or the like, there is a risk that blood or other germs may adhere. Therefore, one electronic cassette 20 can be repeatedly used by sterilizing and cleaning the casing 30 as a waterproof and airtight structure as necessary.

  A connection terminal 20 </ b> A for connecting a communication cable is provided on the side surface of the housing 30 of the electronic cassette 20. Further, the inside of the housing 30 faces the opposite direction of the grid 34 for removing scattered radiation of the radiation X and the display surface 28A of the display 28 from the irradiation surface 32 side of the housing 30 to which the radiation X is irradiated. Is provided on the opposite side of the display surface 28A, and includes a substantially rectangular irradiation surface 36A on which the radiation X is irradiated, and detects the radiation dose of the radiation X transmitted through the patient 14 and irradiated from the irradiation surface 36A. A radiation detector 36 that outputs image information indicating a radiation image corresponding to the radiation dose, and a lead plate 38 that is interposed between the display 28 and the radiation detector 36 and absorbs backscattered radiation X. They are arranged in order.

  In addition, a case 40 that houses an electronic circuit including a microcomputer and a rechargeable secondary battery is disposed on one end side inside 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.

  FIG. 3 is a perspective view showing a main configuration of the radiation irradiation apparatus 18 according to the present embodiment.

  As shown in the figure, the radiation irradiation device 18 is provided between a radiation source 42 that emits radiation X, and between the radiation source 42 and the electronic cassette 20, and four slit plates 44A, 44B, 44C, and 44D. And an aperture portion 44 configured to include

  Each of the slit plates 44A to 44D is made of a material that shields the radiation X such as lead or tungsten, and is a plate member having a rectangular shape in plan view that gradually increases in thickness in the height direction from the front end portion to the rear end portion. In the diaphragm portion 44, 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 the slit plates 44A to 44A. Each of the slit plates 44A to 44D is arranged so that an opening region 51 having a rectangular shape in plan view is formed by the tip of 44D.

  Here, the slit plate 44A and the slit plate 44B are configured to be movable in the x direction in the figure, whereas the slit plate 44C and the slit plate 44D are in the y direction in the figure which is perpendicular to the x direction. It is configured to be movable. In the diaphragm portion 44 according to the present embodiment, the movable range of each of the slit plates 44A to 44D is in a state where the tip portions of the slit plates arranged in contact with each other, that is, the opening region 51 is fully closed. The range from the state to the state to the state in which the opening region 51 has a rectangular shape in plan view and has a maximum area (hereinafter, referred to as “fully open state”).

  Further, in the radiation irradiation apparatus 18 according to the present embodiment, the slit plate 44A is moved by the driving force of the motor 146 (see FIG. 5) being transmitted through a transmission means (not shown), and the slit plate 44B is moved by the motor 148 ( 5) is transmitted through a transmission means (not shown) and moved, and the slit plate 44C is moved by transmission of a driving force of the motor 150 (see FIG. 5) through a transmission means (not shown). In addition, the slit plate 44D moves when the driving force of the motor 152 (see FIG. 5) is transmitted via a transmission means (not shown).

  On the other hand, as shown in FIG. 1, the radiation irradiation apparatus 18 according to the present embodiment is made of a material that shields radiation X, such as lead and tungsten, and a storage box 52 in which the radiation source 42 and the throttle unit 44 are stored. It has. As shown in the figure, the storage box 52 is formed with an opening 52 </ b> A for irradiating the radiation X emitted from the radiation source 42 and passing through the diaphragm 44 toward the irradiation surface 32 of the electronic cassette 20. .

  Here, the opening 52A has a direct line of the radiation X that has passed through the opening region 51 when the slit plates 44A to 44D in the diaphragm 44 are fully opened, and the thickness of the slit plates 44A to 44D. Both the radiation X (hereinafter referred to as “transmission line”) transmitted with a corresponding transmitted dose can be emitted.

  In the imaging system 10 according to the present embodiment, the radiation X is irradiated on the entire irradiation surface 32 of the electronic cassette 20 when the slit plates 44A to 44D of the diaphragm unit 44 are fully opened. In addition, the electronic cassette 20 and the radiation irradiation device 18 are positioned in advance.

  On the other hand, FIG. 4 shows a schematic diagram illustrating an example of a state in which IVR is performed on the patient 14.

  As shown in the figure, a catheter 60 is used in this IVR. The catheter 60 according to the present embodiment is provided with a black and white striped pattern along the longitudinal direction on the surface thereof. Here, the striped pattern includes a wide black region, a narrow white region, a narrow black region, and a wide white region as a group, and a plurality of groups are continuously provided in the longitudinal direction. .

  On the other hand, the skin near the insertion port of the catheter 60 in the patient 14 is irradiated with a light beam on the surface of the catheter 60 inserted into the insertion port, so that the reflection photosensor 62 can receive the reflected light of the light beam. Is provided. The reflective photosensor 62 receives the reflected light from the surface of the catheter 60, converts the received light into an electrical signal, and transmits it to the console 26.

  Next, with reference to FIG. 5, the configuration of the main part of the electrical system of the imaging system 10 according to the present embodiment will be described.

  As shown in the figure, the radiation irradiation apparatus 18 according to the present embodiment is provided with a connection terminal 18 </ b> A for communicating with the console 26. In contrast, the console 26 according to the present embodiment has a connection terminal 26 </ b> A for communicating with the radiation irradiation device 18, a connection terminal 26 </ b> B for communicating with the electronic cassette 20, and the reflective photosensor 62. A connection terminal 26C for receiving an electrical signal is provided.

  The radiation irradiation device 18 is connected to the console 26 via a communication cable 70. The reflective photosensor 62 is connected to the console 26 via the communication cable 71. The electronic cassette 20 has a communication cable 72 connected to the connection terminal 20 </ b> A and is connected to the console 26 via the communication cable 72 when capturing a radiographic image. In the present embodiment, in order to increase the speed of data transfer between the electronic cassette 20 and the console 26, an optical communication cable employing an optical fiber is used as the communication cable 72. Data is transferred between the console 20 and the console 26.

  The radiation detector 36 incorporated in the electronic cassette 20 is an indirect conversion method in which radiation is converted into light by a scintillator and then converted into charges by a photoelectric conversion element such as a photodiode, and radiation is converted into charges by a semiconductor layer such as amorphous selenium. Any direct conversion method may be used. The direct conversion type radiation detector 36 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 74. 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 indirect conversion radiation detector 36 uses a phosphor material and a photoelectric conversion element (photodiode) indirectly instead of the radiation-charge conversion material that directly converts the radiation X such as amorphous selenium into electric charges. It may be converted into an electric charge. As phosphor materials, gadolinium sulfate (GOS) and cesium iodide (CsI) are well known. In this case, radiation X-light conversion is performed using a phosphor material, and light-charge conversion is performed using a photodiode of a photoelectric conversion element. The electronic cassette 20 according to the present embodiment includes an indirect conversion radiation detector 36.

  In addition, on the TFT active matrix substrate 74, a pixel unit 80 including a storage capacitor 76 for storing charges generated in the photoelectric conversion layer and a TFT 78 for reading out the charges stored in the storage capacitor 76 (FIG. 5). In this example, a large number of photoelectric conversion layers and photoelectric conversion elements corresponding to the individual pixel portions 80 are schematically shown as photoelectric conversion portions 82). Along with this, charges generated in the photoelectric conversion layer are stored in the storage capacitors 76 of the individual pixel units 80. As a result, the 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 74 is extended in a certain direction (row direction), a plurality of gate wirings 84 for turning on and off the TFTs 78 of the individual pixel portions 80, and a direction (column) orthogonal to the gate wirings 84. A plurality of data wirings 86 are provided for reading the stored charge from the storage capacitor 76 through the TFT 78 which is turned on. Each gate wiring 84 is connected to a gate line driver 88, and each data wiring 86 is connected to a signal processing unit 90. When charges are accumulated in the storage capacitors 76 of the individual pixel units 80, the TFTs 78 of the individual pixel units 80 are sequentially turned on in units of rows by a signal supplied from the gate line driver 88 via the gate wiring 84. The charge stored in the storage capacitor 76 of the pixel unit 80 for which is turned on is transmitted as a charge signal through the data wiring 86 and input to the signal processing unit 90. Accordingly, the charges accumulated in the storage capacitors 76 of the individual pixel units 80 are sequentially read out in units of rows.

  FIG. 6 shows an equivalent circuit diagram focusing on one pixel portion of the radiation detector 36 according to the present exemplary embodiment.

  As shown in the figure, the source of the TFT 78 is connected to the data wiring 86, and the data wiring 86 is connected to the signal processing unit 90. The drain of the TFT 78 is connected to the storage capacitor 76 and the photoelectric conversion unit 82, and the gate of the TFT 78 is connected to the gate wiring 84.

  The signal processing unit 90 includes a sample hold circuit 92 for each data wiring 86. The charge signal transmitted through each data wiring 86 is held in the sample hold circuit 92. The sample hold circuit 92 includes an operational amplifier 92A and a capacitor 92B, and converts the charge signal into an analog voltage. The sample hold circuit 92 is provided with a switch 92C as a reset circuit that shorts both electrodes of the capacitor 92B and discharges the electric charge accumulated in the capacitor 92B.

  A multiplexer 94 and an A / D (analog / digital) converter 96 are sequentially connected to the output side of the sample and hold circuit 92, and the charge signals held in the individual sample and hold circuits are converted into analog voltages to be converted into the multiplexer 94. Are sequentially input (serially) and converted into digital image information by the A / D converter 96.

  As shown in FIG. 5, a line memory 98 is connected to the signal processing unit 90, and image information output from the A / D converter 96 of the signal processing unit 90 is sequentially stored in the line memory 98. The line memory 98 has a storage capacity capable of storing image information indicating a radiation image for a predetermined number of lines, and the read image information for one line is stored in the line memory each time the charge is read line by line. 98 are sequentially stored.

  The line memory 98 is connected to a cassette control unit 100 that controls the operation of the entire electronic cassette 20. The cassette control unit 100 is realized by a microcomputer, and an optical communication control unit 102 is connected thereto. The optical communication control unit 102 is connected to the connection terminal 20A, and controls transmission of various information to and from an external device connected via the connection terminal 20A. Therefore, the cassette control unit 100 can transmit and receive various types of information to and from an external device via the optical communication control unit 102.

  The electronic cassette 20 includes a display driver 104 that controls display on the display 28, and a cassette control unit 100 is connected to the display driver 104. The cassette control unit 100 reads the image information stored in the line memory 98 and displays the radiation image indicated by the image information on the display surface 28A of the display 28. Note that the radiation image indicated by the image information obtained by the radiation detector 36 is displayed on the display 28 according to the present embodiment in a substantially actual size.

  Further, the electronic cassette 20 includes a power supply unit 106, and the above-described various circuits and elements (a gate line driver 88, a signal processing unit 90, a line memory 98, an optical communication control unit 102, and a micro controller that functions as the cassette control unit 100). The computer is operated by the power supplied from the power supply unit 106. The power supply unit 106 incorporates a 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 26 is configured as a server computer and includes a touch panel display or the like in which a transparent touch panel is superimposed on the display. Various information such as operation menus and captured radiographic images are displayed on the display surface of the display. And a UI (User Interface) panel 110 on which desired information and instructions are input when the user touches the touch panel with a touch pen, and a plurality of keys. Various information and operation instructions are displayed. And an input operation panel 112 (see also FIG. 1).

  The console 26 temporarily stores a CPU (Central Processing Unit) 114 that controls the operation of the entire apparatus, a ROM (Read Only Memory) 116 in which various programs including a control program are stored in advance, and various data. A RAM (Random Access Memory) 118 and an HDD (Hard Disk Drive) 120 that stores and holds various data are provided.

  In addition, the console 26 controls the display of the UI panel 110, detects the operation state of the touch panel, the UI panel control unit 122, detects the operation state of the operation panel 112, and the connection terminal 26A. And a communication interface (I / F) unit 126 that transmits and receives various kinds of information such as exposure conditions and state information of the radiation irradiation device 18 to and from the radiation irradiation device 18 via the connection terminal 26A and the communication cable 70. Connected to the connection terminal 26B, connected to the connection terminal 26C, an optical communication control unit 128 that transmits and receives various information such as image information to and from the electronic cassette 20 via the connection terminal 26B and the communication cable 72, Reception of an electrical signal from the reflective photosensor 62 via the connection terminal 26C and the communication cable 71 It includes an external I / F unit 130 which performs the.

  The CPU 114, the ROM 116, the RAM 118, the HDD 120, the UI panel control unit 122, the operation input detection unit 124, the communication I / F unit 126, the optical communication control unit 128, and the external I / F unit 130 are mutually connected via the system bus BUS. It is connected. Therefore, the CPU 114 can access the ROM 116, the RAM 118, and the HDD 120, controls the display of various information on the display of the UI panel 110 via the UI panel control unit 122, and controls the display via the UI panel control unit 122. Understanding of the user's operation state with respect to the touch panel of the UI panel 110, understanding of the user's operation state with respect to the operation panel 112 via the operation input detection unit 124, and various information with the radiation irradiation apparatus 18 via the communication I / F unit 126. Control of transmission / reception, control of transmission / reception of various information with the electronic cassette 20 via the optical communication control unit 128, and acquisition of the detection result of the reflective photosensor 62 via the external I / F unit 130 can be performed. .

  Note that the touch panel of the UI panel 110 according to the present embodiment is configured by a large number of switches using transparent electrodes arranged in a matrix, and the user uses a touch pen (not shown) to display the screen on the UI panel 110. Touching any one of the switches on the touch panel turns on. When any switch on the touch panel is turned on, the UI panel control unit 122 outputs coordinate information representing the position of the turned-on switch in two-dimensional orthogonal coordinates in the matrix to the CPU 114. When coordinate information is input from the UI panel control unit 122, the CPU 114 stores the coordinate information in the HDD 120.

  On the other hand, the radiation irradiation device 18 includes an irradiation device control unit 140 that controls the operation of the radiation irradiation device 18 as a whole. The irradiation device control unit 140 is realized by a microcomputer, and a communication I / F unit 142 is connected thereto. The communication I / F unit 142 is connected to the connection terminal 18A, and controls transmission of various information to and from the console 26 connected via the connection terminal 18A. Therefore, the irradiation apparatus control unit 140 can transmit and receive various types of information to and from the console 26 via the communication I / F unit 142. Further, the radiation source control unit 140 is connected to the radiation source 42, and the irradiation device control unit 140 controls the radiation source 42 based on the exposure conditions received via the communication I / F unit 142.

  Further, the radiation irradiation device 18 has a motor 146 that generates a driving force for moving the slit plate 44A, a motor 148 that generates a driving force for moving the slit plate 44B, and a motor for moving the slit plate 44C. A motor 150 that generates a driving force and a motor 152 that generates a driving force for moving the slit plate 44D are provided.

  The radiation irradiation device 18 controls the motor driver 154 that controls the drive of the motor 146, the motor driver 156 that controls the drive of the motor 148, the motor driver 158 that controls the drive of the motor 150, and the drive control of the motor 152. And a motor driver 160 for performing.

  The motor 146 is connected to the irradiation device controller 140 via the motor driver 154, the motor 148 is connected to the irradiation device controller 140 via the motor driver 156, and the motor 150 is connected to the irradiation device controller 140 via the motor driver 158. The motor 152 is connected to the irradiation device control unit 140 via the motor driver 160. Accordingly, the driving of the motors 146, 148, 150, and 152 is controlled by the irradiation device control unit 140 in accordance with an instruction from the console 26.

By the way, in the imaging system 10 according to the present embodiment, the cumulative exposure amount per unit area (1 cm ² in the present embodiment) from the start of the treatment in the patient 14 is set to a predetermined exposure dose threshold value. In this case, the exposure system is equipped with an exposure dose limiting function for limiting the exposure dose to the irradiation field excluding the region of interest of the radiation X. For this reason, the imaging system 10 according to the present embodiment has the above-described exposure dose. Information indicating the dose threshold (hereinafter referred to as “exposure dose threshold information”) is stored in advance in the HDD 120 of the console 26 .

  FIG. 7 schematically shows an example of the exposure dose threshold information. As shown in the figure, the exposure dose threshold information according to the present embodiment stores the exposure dose threshold for each organ type such as heart, lung, and stomach. In addition, what is necessary is just to set the said dose threshold value information based on the medical exposure guideline etc. by the Japan Radiation Engineers Association.

  Next, the configuration of the radiation detector 36 in the case of adopting an indirect conversion method in which radiation is indirectly converted into electric charges using a phosphor material and a photoelectric conversion element will be described.

  FIG. 8 is a schematic cross-sectional view schematically showing the configuration of three pixel portions of the indirect conversion type radiation detector 36 according to an embodiment of the present invention.

  In the radiation detector 36, a signal output unit 302, a photoelectric conversion unit 82, and a scintillator 304 are sequentially stacked on an insulating substrate 300, and a pixel unit is configured by the signal output unit 302 and the photoelectric conversion unit 82. ing. A plurality of pixel units are arranged on the substrate 300, and the signal output unit 302 and the photoelectric conversion unit 82 in each pixel unit are configured to overlap each other.

  The scintillator 304 is formed on the photoelectric conversion unit 82 via a transparent insulating film 306, and a phosphor that emits light by converting radiation incident from above (on the side opposite to the substrate 300) into light is formed. Is. By providing such a scintillator 304, the radiation transmitted through the subject is absorbed and light is emitted.

  The wavelength range of the light emitted by the scintillator 304 is preferably the visible light range (wavelength 360 nm to 830 nm), and in order to enable monochrome imaging by the radiation detector 36, the wavelength range of green is included. Is more preferable.

  Specifically, the phosphor used in the scintillator 304 preferably contains cesium iodide (CsI) when imaging using X-rays as radiation, and has an emission spectrum of 420 nm to 600 nm at the time of X-ray irradiation. It is particularly preferable to use CsI (Tl). Note that the emission peak wavelength of CsI (Tl) in the visible light region is 565 nm.

  For example, when the scintillator 304 is formed of a columnar crystal such as CsI (Tl), the scintillator 304 may be formed by vapor deposition on a vapor deposition substrate. When the scintillator 304 is formed by vapor deposition as described above, an Al plate is often used as the vapor deposition substrate from the viewpoint of X-ray transmittance and cost, but is not limited thereto. When GOS is used as the scintillator 304, the scintillator 304 may be formed by applying GOS to the surface of the TFT active matrix substrate 74 without using a vapor deposition substrate.

  The photoelectric conversion unit 82 includes an upper electrode 310, a lower electrode 312, and a photoelectric conversion film 314 disposed between the upper and lower electrodes.

Since it is necessary for the upper electrode 310 to cause the light generated by the scintillator 304 to be incident on the photoelectric conversion film 314, it is preferable that the upper electrode 310 be formed of a conductive material that is transparent at least with respect to the emission wavelength of the scintillator 304. It is preferable to use a transparent conductive oxide (TCO) having a high transmittance for visible light and a small resistance value. Note that although a metal thin film such as Au can be used as the upper electrode 310, the TCO is preferable because the resistance value is likely to increase when the transmittance of 90% or more is obtained. For example, ITO, IZO, AZO, FTO, SnO ₂ , TiO ₂ , ZnO _{2 and the} like can be preferably used, and ITO is most preferable from the viewpoint of process simplicity, low resistance, and transparency. Note that the upper electrode 310 may have a single configuration common to all pixel portions, or may be divided for each pixel portion.

  The photoelectric conversion film 314 absorbs light emitted from the scintillator 304 and generates charges corresponding to the absorbed light. The photoelectric conversion film 314 may be formed using a material that generates charges when irradiated with light, and can be formed using, for example, amorphous silicon, an organic photoelectric conversion material, or the like. The photoelectric conversion film 314 containing amorphous silicon has a wide absorption spectrum and can absorb light emitted by the scintillator 304. If the photoelectric conversion film 314 containing an organic photoelectric conversion material has a sharp absorption spectrum in the visible range, electromagnetic waves other than light emitted by the scintillator 304 are hardly absorbed by the photoelectric conversion film 314, and radiation such as X-rays. Can be effectively suppressed noise generated by the absorption by the photoelectric conversion film 314.

  The organic photoelectric conversion material constituting the photoelectric conversion film 314 is preferably such that its absorption peak wavelength is closer to the emission peak wavelength of the scintillator 304 in order to absorb light emitted by the scintillator 304 most efficiently. Ideally, the absorption peak wavelength of the organic photoelectric conversion material matches the emission peak wavelength of the scintillator 304, but if the difference between the two is small, the light emitted from the scintillator 304 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 304 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 304, the difference between the peak wavelengths can be within 5 nm. Thus, the amount of charge generated in the photoelectric conversion film 314 can be substantially maximized.

  Next, the photoelectric conversion film 314 applicable to the radiation detector 36 according to the present embodiment will be specifically described.

Organic electromagnetic wave absorption / photoelectric conversion part in the radiation detector 36 according to the present invention, comprising a pair of lower electrodes 312, an upper electrode 310, lower electrode 312, the photoelectric conversion layer 314 sandwiched between the upper electrode 310 It can be composed of layers. 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 improvement. It can be formed by stacking or mixing parts.

  The organic layer preferably contains an organic p-type compound or an organic n-type compound.

  The organic p-type semiconductor (compound) is a donor organic semiconductor (compound) mainly represented by a hole-transporting organic compound and refers to 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. Therefore, any organic compound can be used as the donor organic compound as long as it is an electron-donating organic compound.

  An organic n-type semiconductor (compound) is an acceptor organic semiconductor (compound) mainly represented by an electron-transporting organic compound and refers to 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, as the acceptor organic compound, any organic compound can be used as long as it is an electron-accepting organic compound.

  The materials applicable as the organic p-type semiconductor and the organic n-type semiconductor and the configuration of the photoelectric conversion film 314 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 314 may be formed by further containing fullerenes or carbon nanotubes.

  The thickness of the photoelectric conversion film 314 is preferably as large as possible in terms of absorbing light from the scintillator 304. However, when the thickness is larger than a certain level, the photoelectric conversion film 314 is generated in the photoelectric conversion film 314 by a bias voltage applied from both ends of the photoelectric conversion film 314. Since electric field strength is reduced and charges cannot be collected, the thickness is preferably 30 nm to 300 nm, more preferably 50 nm to 250 nm, and particularly preferably 80 nm to 200 nm.

  In the radiation detector 36 illustrated in FIG. 8, the photoelectric conversion film 314 has a single-sheet configuration common to all pixel units, but may be divided for each pixel unit.

  The lower electrode 312 is a thin film divided for each pixel portion. The lower electrode 312 can be made of a transparent or opaque conductive material, and aluminum, silver, or the like can be preferably used.

  The thickness of the lower electrode 312 can be, for example, 30 nm or more and 300 nm or less.

  In the photoelectric conversion unit 82, by applying a predetermined bias voltage between the upper electrode 310 and the lower electrode 312, one of charges (holes, electrons) generated in the photoelectric conversion film 314 is moved to the upper electrode 310. And the other can be moved to the lower electrode 312. In the radiation detector 36 of the present embodiment, a wiring is connected to the upper electrode 310, and a bias voltage is applied to the upper electrode 310 via this wiring. In addition, the polarity of the bias voltage is determined so that electrons generated in the photoelectric conversion film 314 move to the upper electrode 310 and holes move to the lower electrode 312, but this polarity is opposite. May be.

  The photoelectric conversion unit 82 constituting each pixel unit only needs to include at least the lower electrode 312, the photoelectric conversion film 314, and the upper electrode 310, but in order to suppress an increase in dark current, the electron blocking film 316 and the holes are included. It is preferable to provide at least one of the blocking films 318, and it is more preferable to provide both.

  The electron blocking film 316 can be provided between the lower electrode 312 and the photoelectric conversion film 314. When a bias voltage is applied between the lower electrode 312 and the upper electrode 310, electrons are transferred from the lower electrode 312 to the photoelectric conversion film 314. It is possible to suppress the dark current from increasing due to the injection of.

  An electron-donating organic material can be used for the electron blocking film 316.

  The material actually used for the electron blocking film 316 may be selected according to the material of the adjacent electrode, the material of the adjacent photoelectric conversion film 314, etc., and 1.3 eV or more from the work function (Wf) of the material of the adjacent electrode. Those having a large electron affinity (Ea) and an Ip equivalent to or smaller than the ionization potential (Ip) of the material of the adjacent photoelectric conversion film 314 are 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 316 is preferably 10 nm or more and 200 nm or less, more preferably 30 nm or more and 150 nm or less, and 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 82. Is from 50 nm to 100 nm.

  The hole blocking film 318 can be provided between the photoelectric conversion film 314 and the upper electrode 310. When a bias voltage is applied between the lower electrode 312 and the upper electrode 310, the hole blocking film 318 is transferred from the upper electrode 310 to the photoelectric conversion film 314. It is possible to suppress the increase in dark current due to the injection of holes.

  An electron-accepting organic material can be used for the hole blocking film 318.

  The thickness of the hole blocking film 318 is preferably 10 nm or more and 200 nm or less, more preferably 30 nm or more and 150 nm or less, in order to reliably exhibit the dark current suppressing effect and prevent a decrease in the photoelectric conversion efficiency of the photoelectric conversion unit 82. Preferably they are 50 nm or more and 100 nm or less.

  The material actually used for the hole blocking film 318 may be selected according to the material of the adjacent electrode, the material of the adjacent photoelectric conversion film 314, etc., and 1.3 eV from the work function (Wf) of the material of the adjacent electrode. As described above, it is preferable that the ionization potential (Ip) is large and the Ea is equal to or larger than the electron affinity (Ea) of the material of the adjacent photoelectric conversion film 314. 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.

  In the case where the bias voltage is set so that holes move to the upper electrode 310 and electrons move to the lower electrode 312 among the charges generated in the photoelectric conversion film 314, the electron blocking film 316 and the hole blocking are set. The position of the film 318 may be reversed. Further, it is not necessary to provide both the electron blocking film 316 and the hole blocking film 318. If either one is provided, a certain degree of dark current suppressing effect can be obtained.

  A signal output unit 302 is formed on the surface of the substrate 300 below the lower electrode 312 of each pixel unit.

  FIG. 9 schematically shows the configuration of the signal output unit 302.

  Corresponding to the lower electrode 312, there are formed a storage capacitor 76 for storing the charge transferred to the lower electrode 312, and a TFT 78 for converting the charge stored in the storage capacitor 76 into an electric signal and outputting it. The region where the storage capacitor 76 and the TFT 78 are formed has a portion that overlaps the lower electrode 312 in a plan view. With such a configuration, the signal output unit 302 and the photoelectric conversion unit 82 in each pixel unit are provided. Will have an overlap in the thickness direction. In order to minimize the plane area of the radiation detector 36 (pixel portion), it is desirable that the region where the storage capacitor 76 and the TFT 78 are formed is completely covered by the lower electrode 312.

  The storage capacitor 76 is electrically connected to the corresponding lower electrode 312 through a conductive material wiring formed through an insulating film 319 provided between the substrate 300 and the lower electrode 312. Thereby, the charges collected by the lower electrode 312 can be moved to the storage capacitor 76.

  In the TFT 78, a gate electrode 320, a gate insulating film 322, and an active layer (channel layer) 324 are stacked, and a source electrode 326 and a drain electrode 328 are formed on the active layer 324 at a predetermined interval. The active layer 324 can be formed of, for example, amorphous silicon, amorphous oxide, organic semiconductor material, carbon nanotube, or the like. Note that the material forming the active layer 324 is not limited thereto.

The amorphous oxide that can form the active layer 324 is preferably an oxide containing at least one of In, Ga, and Zn (for example, In—O-based), and at least two of In, Ga, and Zn. Oxides containing one (for example, 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 that can form the active layer 324 is not limited thereto.

  Examples of the organic semiconductor material that can constitute the active layer 324 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 is demonstrated in detail in Unexamined-Japanese-Patent No. 2009-212389, description is abbreviate | omitted.

  If the active layer 324 of the TFT 78 is formed of an amorphous oxide, an organic semiconductor material, or a carbon nanotube, it does not absorb radiation such as X-rays, or even if it is absorbed, it remains extremely small. The generation of noise in 302 can be effectively suppressed.

Further, when the active layer 324 is formed of carbon nanotubes, the switching speed of the TFT 78 can be increased, and the TFT 78 having a low light absorption in the visible light region can be formed. In addition, when the active layer 324 is formed of carbon nanotubes, the performance of the TFT 78 is remarkably deteriorated only by mixing a very small amount of metallic impurities into the active layer 324. Therefore, extremely high purity carbon nanotubes are separated by centrifugation or the like.・ It needs to be extracted and formed.

  Here, any of the above-described amorphous oxide, organic semiconductor material, carbon nanotube, and organic photoelectric conversion material can be formed at a low temperature. Therefore, the substrate 300 is not limited to a substrate having high heat resistance such as a semiconductor substrate, a quartz substrate, and a glass substrate, and a flexible substrate such as plastic, an 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. If such a plastic flexible substrate is used, it is possible to reduce the weight, which is advantageous for carrying around, for example.

  In addition, the substrate 300 is provided with 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.

  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 also be used for 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, warping after production is small and it is difficult to crack. In addition, aramid can form a substrate thinner than a glass substrate or the like. Note that the substrate 300 may be formed by stacking an ultrathin glass substrate and aramid.

  Bionanofiber is a composite of cellulose microfibril bundles (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 60-70% 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 substrate 300 can be thinly formed.

  In this embodiment mode, the signal output portion 302, the photoelectric conversion portion 82, and the transparent insulating film 306 are formed in this order on the substrate 300, and the scintillator 304 is attached to the substrate 300 using an adhesive resin having low light absorption. The radiation detector 36 is formed by attaching. Hereinafter, the substrate 300 formed up to the transparent insulating film 306 is referred to as a TFT active matrix substrate (hereinafter also referred to as “TFT substrate”) 74.

  In the electronic cassette 20 according to the present embodiment, the radiation detector 36 is incorporated so that the radiation X is irradiated from the TFT substrate 74 side.

  Here, as shown in FIG. 10, the radiation detector 36 is irradiated with radiation from the side on which the scintillator 304 is formed, and reads a radiation image by the TFT substrate 74 provided on the back side of the incident surface of the radiation. In the case of the so-called back side scanning method (so-called PSS (Penetration Side Sampling) method), the scintillator 304 emits light more strongly on the upper surface side of the figure (opposite side of the TFT substrate 74), and radiation is irradiated from the TFT substrate 74 side. Thus, in the case of a so-called surface reading method (so-called ISS (Irradiation Side Sampling) method) in which a radiation image is read by a TFT substrate 74 provided on the surface side of the radiation incident surface, radiation transmitted through the TFT substrate 74 is transmitted. The light enters the scintillator 304 and the TFT substrate 74 side of the scintillator 304 emits light more intensely. Electric charges are generated by the light generated by the scintillator 304 in each photoelectric conversion unit 82 provided on the TFT substrate 74. For this reason, since the radiation detector 36 is closer to the light emission position of the scintillator 304 with respect to the TFT substrate 74 when the front surface reading method is used than when the rear surface reading method is used, the resolution of the radiation image obtained by imaging is higher. high.

In the radiation detector 36, the photoelectric conversion film 314 is made of an organic photoelectric conversion material, and radiation is hardly absorbed by the photoelectric conversion film 314. For this reason, the radiation detector 36 according to the present embodiment suppresses a decrease in sensitivity to the radiation X because the amount of radiation absorbed by the photoelectric conversion film 314 is small even when the radiation is transmitted through the TFT substrate 74 by the surface reading method. be able to. In the surface reading method, radiation passes through the TFT substrate 74 and reaches the scintillator 304. Thus, when the photoelectric conversion film 314 of the TFT substrate 74 is formed of an organic photoelectric conversion material, the radiation in the photoelectric conversion film 314 is obtained. Therefore, it is suitable for the surface reading method.

Further, the amorphous oxide constituting the active layer 324 of the TFT 78 and the organic photoelectric conversion material constituting the photoelectric conversion film 314 can be formed at a low temperature. Therefore, the substrate 300 can be formed of a plastic resin, aramid, or bionanofiber that absorbs little radiation. Since the substrate 300 formed in this way has a small amount of radiation absorption, a reduction in sensitivity to the radiation X can be suppressed even when the radiation passes through the TFT substrate 74 by the surface reading method.

Further, for example, the radiation detector 36 is attached to the irradiation surface 32 portion in the housing 30 so that the TFT substrate 74 is on the irradiation surface 32 side, and the substrate 300 is made of a highly rigid plastic resin, aramid, or bio-nanofiber. When formed, since the radiation detector 36 itself has high rigidity, the irradiation surface 32 portion of the housing 30 can be formed thin. Further, when the substrate 300 is formed of a highly rigid plastic resin, aramid, or bionanofiber, the radiation detector 36 itself has flexibility, so that even when an impact is applied to the irradiation surface 32, the radiation detector 36 is damaged. It ’s hard.

  Next, the operation of the imaging system 10 according to the present embodiment will be described.

  When performing an IVR on a patient 14 using the imaging system 10 according to the present embodiment, an operator who performs the IVR firstly has coordinate information indicating a planned approach path of the catheter 60 as a preparation stage of the IVR. Enter as shown below.

  That is, the surgeon first lies the patient 14 on the mounting table 16 </ b> A in a state where the insertion opening of the catheter 60 and the lesioned part can be imaged by the electronic cassette 20. Next, the surgeon opens the slit plates 44 </ b> A to 44 </ b> D of the diaphragm 44 to the radiation irradiation device 18 through the console 26 and then emits the radiation X with a predetermined exposure dose. In this manner, the radiation source 42 is controlled so that the electronic cassette 20 is controlled to take a radiation image. As a result, the electronic cassette 20 captures a radiographic image, as will be described in detail in the description of a radiographic image capturing process (see FIG. 11) described later, and transmits image information obtained by the capturing to the console 26. The On the other hand, when the image information is received, the console 26 displays the radiographic image indicated by the image information on the display of the UI panel 110.

  Therefore, the surgeon traces the planned entry path of the catheter 60 in the body of the patient 14 on the radiographic image displayed on the display of the UI panel 110 with a touch pen, thereby obtaining coordinate information (hereinafter referred to as “path”). "Coordinate information"). At this time, the surgeon touches the outline of the planned entry path and the outline of an organ (hereinafter referred to as “determination target organ”) existing in the vicinity of the planned entry path and in the region that can be the radiation X irradiation field. The coordinate information indicating the region where the determination target organ exists (hereinafter referred to as “organ coordinate information”) is input, and the name of the determination target organ existing in the region indicated by the organ coordinate information is input. Information (hereinafter referred to as “organ name information”) is input via the operation panel 112. The path coordinate information, the organ coordinate information, and the organ name information input from the operator as described above are stored in the HDD 120 by the console 26 in a state in which the corresponding organ coordinate information and organ name information are associated with each other. .

  When the above preparation steps are completed, the surgeon determines the exposure conditions such as tube voltage and tube current when irradiating the radiation X via the operation panel 112 of the console 26 according to the imaging region and imaging conditions of the patient 14. After performing the exposure condition designation operation for designating, the instruction operation for instructing the start of IVR is performed.

  When the instruction operation is performed, the console 26 executes a radiation image capturing process.

  Next, with reference to FIG. 11, the operation of the console 26 at the time of executing the radiographic image capturing process will be described. FIG. 11 is a flowchart showing the flow of processing of the radiographic image capturing processing program executed by the CPU 114 of the console 26 at this time, and the program is stored in a predetermined area of the ROM 116 in advance.

  In step 200 of the figure, the specified exposure conditions are set by transmitting the specified exposure conditions to the radiation irradiation device 18 and the electronic cassette 20. In response to this, the irradiation apparatus control unit 140 prepares for exposure under the received exposure conditions.

  In the next step 202, information indicating the position of the insertion port of the catheter 60 indicated by the path coordinate information stored in the IVR preparation stage described above is set together with setting instruction information for instructing the setting of the opening state of the restrictor 44. Transmit to the irradiation device 18.

  When the setting instruction information is received, in the radiation irradiation apparatus 18, the position corresponding to the position of the insertion port of the catheter 60 indicated by the information received together with the setting instruction information is set in the opening region 51 by the irradiation apparatus control unit 140. The position of each of the slit plates 44A to 44D so as to be the center and the shape of the opening region 51 is a predetermined shape and the area of the opening region 51 is a predetermined area that is at least narrower than in the fully open state. To control. Note that, in the imaging system 10 according to the present embodiment, a region (hereinafter referred to as “direct radiation field”) on which a direct line in the radiation X of the patient 14 is irradiated as the predetermined shape and the predetermined area. However, the shape and area preset by the surgeon or the like are applied as the shape and area to be a region including at least the region of interest.

  In addition, since the predetermined area is an area irradiated with the direct line of the radiation X, it is preferable to appropriately set according to the size of the lesioned part. However, for example, the irradiation surface of the radiation detector 36 A predetermined fixed area such as an area irradiated with a direct line of radiation X may be applied to an area of a predetermined ratio (10% as an example) with respect to the area of 36A.

  In the next step 204, instruction information for instructing the start of exposure is transmitted to the radiation irradiation device 18 and the electronic cassette 20. In response to this, the radiation source 42 generates and emits radiation at a tube voltage, tube current, or the like according to the exposure conditions received by the radiation irradiation device 18 from the console 26.

  The radiation X emitted from the radiation source 42 reaches the electronic cassette 20 after passing through the patient 14 via the diaphragm 44. As a result, electric charges are accumulated in the accumulation capacitors 76 of the respective pixel portions 80 of the radiation detector 36 incorporated in the electronic cassette 20.

  The cassette control unit 100 of the electronic cassette 20 receives in advance a period from when the instruction information instructing the start of exposure is received until the accumulation of charges in the storage capacitors 76 of the pixel units 80 of the radiation detector 36 is completed. After the elapse of a predetermined period, the gate line driver 88 is controlled so that the gate line driver 88 outputs an ON signal to each gate wiring 84 one line at a time, and each TFT 78 connected to each gate wiring 84 is sequentially output one line at a time. Turn it on.

  In the radiation detector 36, when the TFTs 78 connected to the gate wirings 84 are turned on one line at a time, the charges accumulated in the storage capacitors 76 one line at a time flow out to the data wirings 86 as electric signals. The electric signal flowing out to each data wiring 86 is converted into digital image information by the signal processing unit 90 and stored in the line memory 98.

  The cassette control unit 100 performs predetermined image correction processing on the image information stored in the line memory 98 and transmits the image information to the console 26 via the optical communication control unit 102.

  The cassette control unit 100 repeatedly executes the above operation at a predetermined speed (30 frames / second in the present embodiment) as a moving image shooting speed, and uses the image information subjected to the image correction process. The display driver 104 is controlled to display the displayed radiographic image on the display 28.

  Therefore, in the next step 206, it waits until image information for one frame is received from the electronic cassette 20, and in the next step 208, the received image information is stored in the HDD 120, and further in the next step 210. Then, the UI panel control unit 122 is controlled so that the radiation image indicated by the received image information is displayed on the display of the UI panel 110 for confirmation or the like.

  In the next step 212, position information indicating the position of the distal end portion of the catheter 60 is acquired.

  In the console 26 according to the present embodiment, the CPU 114 executes a position specifying process program for specifying the position of the distal end portion of the catheter 60 in a time-sharing manner in parallel with the radiographic image capturing process program.

  In this position specifying processing program, electrical signals received in real time from the reflective photosensor 62 in time series are wide white areas, narrow black areas, and narrow white areas in the stripe pattern provided on the catheter 60. It is determined that the catheter 60 is moving in the direction in which it is inserted into the body of the patient 14 when it indicates that the region has shifted in the order of the regions, and the amount of movement at this time is represented by the number of occurrences of the wide white region. It is specified by multiplying the width of one group. Similarly, the catheter 60 moves in the direction of being pulled out of the body of the patient 14 when the electrical signal indicates that the wide black region, the narrow white region, and the narrow black region in the striped pattern have shifted in this order. The amount of movement at this time is specified by multiplying the number of appearances of the wide black region by the width of the group of the striped pattern.

  In the position specifying processing program, the movement amount obtained when the catheter 60 is moving in the direction of insertion into the body of the patient 14 obtained by the above processing is integrated, and the catheter 60 is moved from the body of the patient 14. The amount of insertion of the catheter 60 into the body of the patient 14 is specified by subtracting the amount of movement when moving in the direction of removal.

  In the position specifying processing program, the position of the distal end portion of the catheter 60 is specified based on the specified insertion amount and the path coordinate information indicating the planned approach path of the catheter 60 stored in the IVR preparation stage described above. The coordinate information indicating the position (hereinafter referred to as “tip portion coordinate information”) is stored in a predetermined area of the RAM 118 in real time.

  Therefore, in step 212, position information indicating the position of the distal end portion of the catheter 60 is obtained by reading the distal end portion coordinate information stored by the position specifying processing program from the RAM 118.

  In the next step 214, information indicating the position of the distal end portion of the catheter 60 indicated by the acquired position information is transmitted to the radiation irradiating apparatus 18 together with change instruction information for instructing a change in the opening state of the restricting portion 44.

  When the change instruction information is received, in the radiation irradiation apparatus 18, the irradiation apparatus control unit 140 sets the position corresponding to the position of the distal end portion of the catheter 60 indicated by the information received together with the change instruction information in the opening region 51. The positions of the slit plates 44A to 44D are controlled so as to be centered. At this time, the irradiation device control unit 140 controls each of the slit plates 44A to 44D so as to maintain the shape and area of the opening region 51 so far.

  In the imaging system 10 according to the present embodiment, the position of the distal end portion of the catheter 60 is assumed to be the center position of the region of interest, and a radiographic image including at least the region of interest is converted into the electronic cassette 20 by the processing of step 214. Will be displayed on the display 28.

  In the next step 216, the cumulative exposure amount R in the irradiation field of the radiation X at this time is calculated as follows.

  First, accumulation per unit area from the start of treatment to this point in the irradiation field of radiation X (hereinafter referred to as “fully opened irradiation field”) when it is assumed that the aperture state of the aperture 44 is fully open. The exposure dose R is calculated based on factors such as tube voltage and FSD (Focus Skin Distance) that influence the dose of radiation X per unit time.

At this time, in the imaging system 10 according to the present embodiment, as shown schematically in FIG. 12 as an example of the cumulative exposure dose R, each of the fully-open irradiation fields has a unit area (in this embodiment, It is divided into a plurality of rectangular areas 64 of 1 cm ² ) in a matrix form, and is calculated as indicating the cumulative exposure dose for each rectangular area 64. The cumulative exposure dose R can be calculated using, for example, an NDD method (Non Desimeter Dosimetry Method).

  Then, among the calculated cumulative exposure dose R for each rectangular region 64, the cumulative exposure dose R of the rectangular region 64 located in the region where the radiation X is blocked by the respective slit plates 44A to 44D of the diaphragm 44 is used as the corresponding slit plate. It converts into the quantity attenuate | damped by the attenuation factor according to the thickness of the height direction of 44A-44D.

  In the next step 218, the cumulative exposure dose R for each rectangular region 64 included in the region excluding the region of interest in the fully open irradiation field calculated by the processing in step 216 (hereinafter referred to as “non-region of interest irradiation field”) It is determined whether there is an organ that reaches the exposure dose threshold of the organ located at the corresponding position. If the determination is affirmative, the process proceeds to step 220.

  At this time, in step 218, the names of the organs included in the coordinate range corresponding to the non-region of interest irradiation field are specified based on the organ coordinate information and organ name information stored in the IVR preparation stage described above. Then, the exposure dose threshold value (see also FIG. 7) corresponding to the specified organ is read from the HDD 120.

  In step 218, it is determined whether or not there is a cumulative exposure dose R of the rectangular region 64 included in the non-interest region irradiation field that reaches the exposure dose threshold value of the organ located at the corresponding position. At this time, if there is no organ located at the corresponding position, a threshold set in advance by an operator or the like is applied as an exposure dose threshold in a region other than the organ. Here, the exposure dose threshold in the region other than the organ may be set in advance for each region in a wider range than the organ such as the chest, abdomen, arm, and leg, or the entire region other than the organ. A common threshold may be set for.

  In step 220, the shape and area of the opening region 51 of the diaphragm 44 are set such that at least the region of interest is irradiated with a direct line, and the non-region of interest irradiation field is the rectangular region 64 included in the non-region of interest irradiation field. Of these, the cumulative exposure dose R is derived such that the sum of the exposure doses for the rectangular region 64 that reaches the corresponding exposure dose threshold value has a shape and area that minimizes the cumulative exposure dose R.

  In the next step 222, information indicating the shape and area of the opening region 51 derived by the processing in step 220 is transmitted to the radiation irradiation apparatus 18 together with change instruction information for instructing a change in the opening state of the aperture 44, and thereafter To step 230.

  When the change instruction information is received, the radiation irradiating apparatus 18 causes the irradiation apparatus control unit 140 to position the slit plates 44A to 44D so as to have the shape and area indicated by the information received together with the change instruction information. Control.

  On the other hand, when a negative determination is made in step 218, the process proceeds to step 224, in which all the cumulative exposure dose R of the rectangular area 64 included in the non-interest area irradiation field is the exposure dose of the organ located at the corresponding position. It is determined whether or not the amount is less than an amount obtained by subtracting a predetermined margin amount from the threshold value. If a negative determination is made, the process proceeds to step 230 described later, whereas if a positive determination is made, the process proceeds to step 226. .

  At this time, in step 224, the names of organs included in the coordinate range corresponding to the non-region of interest field are identified based on the organ coordinate information and organ name information stored in the IVR preparation stage described above. Then, the exposure dose threshold value (see also FIG. 7) corresponding to the specified organ is read from the HDD 120.

  In step 224, whether or not all of the cumulative exposure dose R of the rectangular region 64 included in the non-interest region irradiation field is less than the amount obtained by subtracting the margin amount from the exposure dose threshold value of the organ located at the corresponding position. Determine whether or not. In this case as well, if there is no organ located at the corresponding position, the threshold set in advance by the operator or the like as the exposure dose threshold in the region other than the organ as in the above-described processing of step 218. Apply.

  In step 226, the shape and area of the opening region 51 of the diaphragm 44 are set such that at least a region of interest is irradiated with a direct line, and for a non-interest region irradiation field, any rectangular region included in the non-interest region irradiation field. 64 is derived so that the total value of the exposure dose for the rectangular region 64 is the maximum in the range that does not reach the corresponding exposure dose threshold.

  In the next step 228, information indicating the shape and area of the opening region 51 derived by the processing in step 226 is transmitted to the radiation irradiation device 18 together with change instruction information for instructing change of the opening state of the aperture 44, and thereafter To step 230.

  When the change instruction information is received, the radiation irradiating apparatus 18 causes the irradiation apparatus control unit 140 to position the slit plates 44A to 44D so as to have the shape and area indicated by the information received together with the change instruction information. Control.

  In step 230, it is determined whether or not the timing for ending the radiographic image capture has arrived. If a negative determination is made, the process returns to step 206, but the process proceeds to step 232 when an affirmative determination is made. In the radiographic image capturing processing program according to the present embodiment, it is determined whether or not the timing for ending the capturing in step 230 has been reached by the surgeon via the input means such as the operation panel 112. However, the present invention is not limited to this, but is not limited to this. Whether the power switch (not shown) of the electronic cassette 20 or the radiation irradiating apparatus 18 is turned off. It goes without saying that other forms, such as a form performed by determining whether or not, may be used.

  In step 232, instruction information for instructing to stop the exposure started by the process of step 204 is transmitted to the radiation irradiation device 18 and the electronic cassette 20, and stored in the next step 234 by the process of step 208. After the image information is transmitted to a RIS (Radiology Information System) server (not shown) via a hospital network (not shown), the radiographic imaging program is terminated. In the RIS server, it is possible to interpret and diagnose a radiographic image taken by a doctor using the image information received from the console 26.

  FIG. 13 is a diagram illustrating an example of a radiation image displayed on the display surface 28A of the display 28 by irradiating the entire surface of the irradiation surface 36A of the radiation detector 36 according to the present embodiment with the radiation X. The patient 14 displayed on the display surface 28A of the display 28 by irradiating the partial area of the irradiation surface 36A of the radiation detector 36 with the radiation X by executing the radiographic imaging processing program according to the present embodiment. It is a figure which shows an example of the radiographic image in the case of being supine in the same state as the state shown in FIG.

  As shown in FIG. 14, in imaging system 10 according to the present embodiment, the irradiation region of the direct line of radiation X can be limited to a predetermined region (a region including a region of interest in the present embodiment). As a result, the exposure dose to the patient 14 can be suppressed, and the transmitted dose at the position of the corresponding slit plate is also applied to the peripheral area of the predetermined area (gradation area in the display image of the figure). Since the corresponding image is displayed in the state shown in the figure as an example, the radiation image of the peripheral part can also be observed.

  As described above in detail, in the present embodiment, from the time when the radiation treatment applied to the subject (patient 14 in the present embodiment) from the radiation source is started for capturing a radiographic image. When it is determined that the cumulative exposure dose (accumulated exposure dose R in this embodiment) reaches a predetermined exposure dose, the exposure dose is limited to the radiation field excluding the region of interest of radiation by the radiation source. Therefore, the exposure dose to the subject can be suppressed while preventing the image quality of the radiation image from being deteriorated in the region of interest.

  Further, in the present embodiment, an opening region provided between the radiation source and the subject and configured to allow a part of the radiation emitted from the radiation source to pass through and to change the area. The diaphragm unit (in this embodiment, the diaphragm unit 44) is provided, and the diaphragm unit is controlled so as to apply the restriction by changing the area of the aperture region of the diaphragm unit. As a result of making the irradiation field region variable, the convenience can be further improved.

  In particular, in the present embodiment, since the diaphragm portion is configured so that the radiation transmission dose decreases as it moves away from the peripheral portion of the opening region, a radiation image in the irradiation field excluding the region of interest is also observed. Can do.

  Further, in the present embodiment, since the cumulative exposure dose is calculated for each of the divided areas defined as the predetermined unit area in the irradiation field, the cumulative exposure dose is calculated for the entire irradiation field. As compared with the above, it is possible to limit the exposure dose to the subject more finely.

  Moreover, in this Embodiment, since the said control is performed following the region of interest which changes with progress of time, the convenience can be improved more.

  In particular, in the present embodiment, the position of a predetermined part of a medical instrument (the catheter 60 in the present embodiment) inserted into the subject is specified, and the specified position is set as the region of interest. Since the control is performed, it is not necessary to set a region of interest in advance, and convenience can be further improved.

Further, when a column crystal of CsI is used as the scintillator 304 and the radiation detector 36 is built in the electronic cassette 20 so as to be a surface reading system, a high-quality image can be obtained. In addition, when an organic photoelectric conversion material is used for the photoelectric conversion film 314, radiation is hardly absorbed by the photoelectric conversion film 314, and more radiation reaches the scintillator 304, thereby improving sensitivity.
As a result, when the aperture 44 is narrowed by the aperture 44 and the peripheral portion of the region of interest is irradiated with the radiation that has passed through the aperture 44, the radiographic image at the periphery may be slightly blurred but may be high. There is no problem because the image quality. Further, doctors and engineers can confirm whether or not the region unnecessary for diagnosis is irradiated by observing the degree of blurring of the radiation image at the peripheral portion of the region of interest.

Moreover, CsI used as a scintillator 304, as shown in FIG. 15, the sensitivity is changed by a temperature change, for example, about 0.3% sensitivity increase of one degree in temperature decreases. On the other hand, GOS hardly changes in sensitivity due to temperature change.

When the electronic cassette 20 performs photographing, various circuits and elements such as the power supply unit 106, the gate line driver 88, and the signal processing unit 90 generate heat. In addition, when moving image shooting is performed with IVR or the like, the shooting time is long. Therefore, there are cases in the electronic cassette 20 using CsI as a scintillator 304, which by heat from various circuits and elements by the animation sensitivity of the scintillator 304 decreases. An operator who performs IVR increases the dose of radiation to be irradiated when trying to maintain the image quality necessary for diagnosis, but when the dose is increased, the exposure dose to the patient also increases. Therefore, as in the present embodiment, the diaphragm portion is configured so that the radiation transmission dose decreases as the distance from the peripheral portion of the opening region decreases, thereby suppressing an increase in the exposure dose to the patient. Can do.

  Further, as shown in FIG. 16, the sensitivity of CsI decreases as the cumulative exposure dose increases, and the sensitivity decreases when the CsI is maintained without being irradiated. When taking a video with IVR or the like, it takes a long time to shoot, and when taking a still image frequently during movie shooting, the radiation dose of still image shooting is 10 to 1000 times that of one frame of movie shooting. Therefore, the sensitivity of the scintillator 304 decreases as the cumulative exposure dose increases. Even in such a case, the surgeon increases the dose of radiation to be irradiated when trying to maintain the image quality necessary for diagnosis, but when the dose is increased, the exposure dose to the patient also increases. Therefore, as in the present embodiment, the diaphragm is configured such that the transmitted dose of radiation decreases as it moves away from the peripheral edge of the opening region, thereby suppressing an increase in the exposure dose to the patient. Can do.

  In addition, according to the present embodiment, the diaphragm portion is configured such that the radiation transmission dose decreases with increasing distance from the peripheral portion of the opening region, so that irradiation is performed in accordance with a decrease in sensitivity of the scintillator 304. Even when the dose of the radiation X is increased, an increase in the exposure dose to the patient can be suppressed.

  Further, since the region of interest is a surgical site, it is necessary to maintain the image quality. However, the region other than the region of interest has little influence even if the captured image is somewhat noisy. Therefore, when it is determined that the cumulative exposure dose R reaches a predetermined exposure dose, if a restriction is imposed on the exposure dose to the irradiation field excluding the region of interest, a sample hold is read out an image of the restricted region. The operational amplifier 92A of the circuit 92 may be expanded to a range not normally used, and control may be performed to reduce exposure to the maximum.

[Second Embodiment]
In the second embodiment, a description will be given of an example of a case in which the cumulative exposure dose for the irradiation field from the time when the treatment starts to the time when the moving image shooting ends is calculated and applied. In addition, since the configuration of the imaging system 10 according to the second embodiment is the same as that according to the first embodiment, description thereof will be omitted, and radiation will be described with reference to FIG. The operation of the console 26 according to the second embodiment at the time of executing the image capturing process will be described. FIG. 17 is a flowchart showing the flow of processing of the radiographic image capturing processing program executed by the CPU 114 of the console 26 at this time. Steps for executing the same processing as FIG. 11 in FIG. The same step number is assigned and its description is omitted. Here, a case where a lesion site to be treated and a treatment time are set in advance will be described.

  In step 215 of the figure, it is determined whether or not the distal end portion of the catheter 60 has reached the lesion to be treated, and if a negative determination is made, the process proceeds to step 216, while an affirmative determination is made. Goes to step 250.

  In step 250, based on the cumulative exposure dose R at this time, the cumulative exposure dose R 'in the radiation X irradiation field from the time when the treatment is started to the time when the moving image capturing ends is calculated as follows.

  First, by the same processing as in step 216, the cumulative exposure dose R up to this point is calculated, and the time from this point to the end of the treatment time (hereinafter referred to as “remaining treatment time”) is calculated. . Then, assuming that the exposure condition at this time is maintained, the cumulative exposure dose for each rectangular area 64 during the remaining treatment time elapses is calculated in the same manner as the cumulative exposure dose R, and the corresponding rectangular area The cumulative exposure dose R ′ is calculated by adding the cumulative exposure dose R for each of 64.

  In the next step 252, a position corresponding to the cumulative exposure dose R ′ for each rectangular region 64 included in the region (non-region of interest irradiation field) excluding the region of interest in the fully open irradiation field calculated by the processing in step 250 is set at a position corresponding to the cumulative exposure dose R ′. It is determined whether there is an organ that reaches the exposure dose threshold of the organ to be determined. If the determination is negative, the process proceeds to step 230. If the determination is affirmative, the process proceeds to step 254.

  At this time, in step 252 above, the names of organs included in the coordinate range corresponding to the non-region of interest irradiation field are specified based on the organ coordinate information and organ name information stored in the IVR preparation stage described above. Then, the exposure dose threshold value (see also FIG. 7) corresponding to the specified organ is read from the HDD 120.

  In step 252, it is determined whether or not there is a cumulative exposure dose R ′ of the rectangular region 64 included in the non-interesting region irradiation field that reaches the exposure dose threshold value of the organ located at the corresponding position. At this time, if there is no organ located at the corresponding position, applying a threshold value preset by the operator or the like as the exposure dose threshold value in the region other than the organ is the same as the processing in step 218. .

  In step 254, the shape and area of the opening region 51 of the diaphragm 44 are set such that at least the region of interest is irradiated with a direct line, and the non-region of interest irradiation field is the rectangular region 64 included in the non-region of interest irradiation field. Of these, the cumulative exposure dose R ′ is derived such that the sum of the exposure doses for the rectangular region 64 that reaches the corresponding exposure dose threshold value has a shape and area that minimizes the cumulative exposure dose R ′.

  In the next step 256, information indicating the shape and area of the opening region 51 derived by the processing in step 254 is transmitted to the radiation irradiation device 18 together with change instruction information for instructing a change in the opening state of the aperture 44, and thereafter To step 230.

  When the change instruction information is received, the radiation irradiating apparatus 18 causes the irradiation apparatus control unit 140 to position the slit plates 44A to 44D so as to have the shape and area indicated by the information received together with the change instruction information. Control.

  As described above in detail, in the present embodiment, in addition to the effects of the first embodiment, the cumulative exposure to the irradiation field from the time when the treatment is started as the cumulative exposure to the time when the moving image shooting is completed. Since the amount is calculated, it is possible to make the cumulative exposure amount up to the time point when the moving image capturing in the irradiation field excluding the region of interest is completed is equal to or less than the predetermined exposure amount.

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

  The above embodiments do not limit the invention according to the claims (claims), and all the combinations of features described in the embodiments are essential for the solution means of the invention. Not exclusively. Even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, as long as an effect is obtained, a configuration from which these some constituent requirements are deleted can be extracted as an invention.

  For example, in each of the above-described embodiments, the case where the cumulative exposure amount is compared with the predetermined exposure threshold value for each of the rectangular regions 64 has been described. However, the present invention is not limited to this, for example, Alternatively, the cumulative exposure dose may be compared with an exposure dose threshold value that is predetermined according to the corresponding area for each range wider than the organ or the organ such as the chest, abdomen, and leg.

  Further, in each of the above embodiments, a case has been described where the cumulative exposure dose of the radiation field excluding the region of interest is compared with the exposure dose threshold, but the present invention is not limited to this. For example, the cumulative exposure dose and the exposure dose threshold value including the region of interest may be compared.

  In each of the above-described embodiments, the case where the throttle unit 44 is controlled to be throttled when the cumulative dose reaches the dose threshold has been described, but the present invention is not limited to this, and in this case In addition to the control, a control may be performed to reduce the dose of the radiation X emitted from the radiation source 42.

  Further, in each of the above embodiments, as a condition for narrowing down the diaphragm 44, the shape and area of the opening region 51 are such that a direct line is irradiated at least for the region of interest, and the non-region of interest region is the non-region of interest. A description will be given of a case in which the condition that the total value of the exposure dose for the rectangular region 64 in which the cumulative exposure dose reaches the corresponding exposure dose threshold among the rectangular regions 64 included in the irradiation field is the minimum is the shape and area. However, the present invention is not limited to this. For example, at least the region of interest is directly irradiated with a line, such as a condition that the shape and area are directly irradiated with the region of interest. It is good also as a form which applies these conditions.

  In each of the above embodiments, the case where the position of each organ of the patient 14 to be treated is specified by inputting organ coordinate information in advance has been described, but the present invention is not limited to this, For example, there is a pattern between an image indicated by image information obtained by imaging the patient 14 to be treated by the electronic cassette 20 and an image indicated by image information obtained by imaging the human body in advance by the electronic cassette 20. It is good also as a form which specifies the position of each organ of the patient 14 made into a treatment target by performing a matching.

  Further, in each of the above-described embodiments, the embodiment has been described with reference to an example in which the position of the distal end portion of the catheter 60 in the body of the patient 14 is specified using the amount of entry of the catheter 60 in the body of the patient 14. The invention is not limited to this, and may be other forms such as a form specified using an image recognition technology, a form specified using an IC tag, a form specified using a magnetic material, and the like.

  As a form in the case of specifying using the image recognition technology, the image indicated by the image information acquired from the electronic cassette 20 when the specification is performed, and obtained by photographing the distal end portion of the catheter 60 with the electronic cassette 20 in advance. By performing pattern matching with the image indicated by the image information, it is possible to exemplify a form for specifying the position of the distal end portion of the catheter 60 in the image indicated by the image information acquired when performing the specification. .

  In addition, as a form in the case of specifying using an IC tag, an IC tag that transmits a predetermined signal is attached to the distal end portion of the catheter 60, and a plurality of antennas are provided in the operating room, and the antenna is received by the antenna. A mode in which the position of the distal end portion of the catheter 60 is specified by specifying the position of the source IC tag by the triangulation technique based on the received intensity of the signal can be exemplified.

  Furthermore, as a form when specifying using a magnetic body, while attaching a magnet to the front-end | tip part of the catheter 60, the position which does not overlap with the radiation detector 36 of the irradiation surface 32 of the electronic cassette 20 (for example, position of case 40) Is provided with a measuring device for measuring the magnitude of the magnetic force of the magnet attached to the tip of the catheter 60, and the magnet attached to the tip of the catheter 60 from the measuring device based on the magnitude of the magnetic force measured by the measuring device. And the position of the distal end of the catheter 60 on the touch panel of the UI panel 110 can be exemplified based on the distance and the coordinate information of the planned entry route.

  As a modification, the magnetic force of a magnet attached to the distal end portion of the catheter 60 is measured, and the position of the distal end portion of the catheter 60 is estimated by acquiring the direction of the magnetic force generation source. It is good. In this case, the coordinate information of the planned entry route is not necessary. In addition, an ultrasonic transmitter or a γ-ray transmitter may be used instead of the magnet. In this case, the distance from the measuring device to the transmitter by measuring the size of the physical quantity transmitted from the transmitter. And the position of the distal end portion of the catheter 60 is estimated using the distance. As described above, any method may be used for estimating the position of the distal end portion of the catheter 60 inserted into the body of the patient 14 in the body of the patient 14.

  Further, in each of the above-described embodiments, a description has been given of an example in which the position of the distal end portion of the catheter 60 inserted into the body of the patient 14 is estimated in the body of the patient 14. It is good also as a form which estimates the position in the body of the patient 14 of parts other than the front-end | tip part of the catheter 60 inserted in the inside of the patient.

  Further, in each of the above embodiments, the case where the diaphragm 44 is configured to be able to change all the area, shape, and position of the opening region 51 has been described, but the present invention is not limited to this, Any one of these or a combination of the two may be configured to be changeable.

  Further, in each of the above-described embodiments, the description has been given of the case where the direction in which each slit plate in the diaphragm portion 44 is movable is a direction orthogonal to the direction in which the radiation X passes, but the present invention is limited to this. However, it may be configured to be movable in the intersecting direction excluding the direction orthogonal to the direction in which the radiation X passes.

  In each of the above embodiments, the slit plate provided in the diaphragm 44 has a rectangular plate shape in plan view in which the thickness in the height direction gradually increases in a straight line shape in cross section from the front end portion to the rear end portion. Although the case where what was comprised with the member was applied was demonstrated, this invention is not limited to this, It is good also as a form which applies the slit plate of the other shape shown by FIGS. 18-20.

  In the example shown in FIG. 18, each of the slit plates 46 </ b> A to 46 </ b> D provided in the diaphragm portion 46 gradually increases in thickness in a straight line shape in cross section from the tip portion to the intermediate portion, and is rectangular in plan view. The slit plate 46A and the slit plate 46B are opposed to each other, the slit plate 46C and the slit plate 46D are opposed to each other, and each of the slit plates 46A to 46D. The slit plates 46 </ b> A to 46 </ b> D are arranged so that an opening region 51 having a rectangular shape in a plan view is formed by the front end portion.

  On the other hand, in the example shown in FIG. 19, the thickness of the slit plates 48 </ b> A to 48 </ b> D provided in the diaphragm 48 increases stepwise as viewed from the periphery of the opening region 51, i.e., gradually increases. The slit plate 48A and the slit plate 48B are opposed to each other, and the slit plate 48C and the slit plate 48D are opposed to each other. The slit plates 48A to 48D are arranged so that the opening regions 51 having a rectangular shape in plan view are formed by the tip portions of the slit plates 48A to 48D.

  Furthermore, in the example shown in FIG. 20, each slit plate group 50A (slit plates 50A1 and 50A2), slit plate group 50B (slit plates 50B1 and 50B2), and slit plate group 50C (slit plates 50C1 and 50C1) provided in the diaphragm unit 50 are provided. 50C2), each slit plate constituting the slit plate group 50D (slit plates 50D1, 50D2) is formed of a flat plate member, and the end faces of the slit plates of the slit plate group 50A and the slit plate group 50B are opposed to each other. In addition, the end faces of the slit plates of the slit plate group 50C and the slit plate group 50D face each other, and an opening region 51 having a rectangular shape in plan view is formed by the end portions of the slit plate groups 50A to 50D. Each slit board group 50A-50D is arrange | positioned.

  In addition, the slit plate of each aperture | diaphragm | squeeze part shown by FIGS. 18-20 is comprised with the material which shields radiation X, such as lead and tungsten, and one slit board group which an edge part opposes is an x direction. A slit that is configured to be movable, and that the other slit plate group is configured to be movable in the y direction, which is a direction orthogonal to the x direction. From the state in which the end portions of the plates are in contact, that is, the state in which the opening region 51 is in a fully closed state to the state in which the opening region 51 has a rectangular shape in plan view and has the maximum area (fully open state). The point set as the range and the point that each slit plate can be moved by the motor are the same as those of the diaphragm unit 44 according to the above embodiment.

  In the case of the diaphragm portion 46 shown in FIG. 18, the same effect as that of the diaphragm portion 44 according to the above embodiment can be obtained. On the other hand, in the case of the diaphragm portion 48 shown in FIG. Compared with the case of being configured to be thicker, the diaphragm portion can be configured more easily. Further, in the case of the diaphragm portion 50 shown in FIG. 20, the degree of freedom such as the shape and area of the opening region 51 can be increased. Can be improved.

  In addition, in each aperture | diaphragm | squeeze part shown in FIG. 3, FIG. 18-20, it is not necessary to necessarily comprise all the slit plates so that a movement is possible, and it should just be a form which comprises at least one slit plate so that a movement is possible. . In this case, it goes without saying that the number of motors for moving the slit plate can be reduced.

  Moreover, in each diaphragm | throttle part shown in FIG. 3, FIG. 18-20, although the shape of all the slit plates which comprise the said diaphragm | throttle part is made into the same shape, it uses for these diaphragm | throttle parts not only in this. It is good also as a form applied combining the slit board currently used. In FIG. 21, a wedge-shaped slit plate (slit plates 44C and 44D) used in the diaphragm unit 44 and a flat slit plate (slit plates 50A1 and 50B1) used in the diaphragm unit 50 are applied. An example of the case is shown.

  Moreover, in each aperture | diaphragm | squeeze part shown in FIG. 3, FIG. 18-FIG. 21, although two pairs of slit plates or slit plate groups which each face each other are applied, not only this but FIG. 22 as an example As shown, a pair of slit plate 43A and slit plate 43B having an L shape in plan view may be applied in combination. In this case, the shape in the thickness direction (height direction) of each of the slit plates 43A and 43B is, for example, a wedge shape or a step shape as shown in FIGS.

  In this case, at least one of the slit plate 43A and the slit plate 43B is configured to be movable in at least one of the x direction and the y direction, and the movable range of each slit plate is such that the opening region 51 is in a fully closed state. The range from the open state to the state in which the opening region 51 has a rectangular shape in plan view and has a maximum area (fully open state), and the movable slit plate is moved by the motor. The point is the same as the other apertures.

  In this case, the number of slit plates can be reduced as compared with other diaphragm portions, and the cost can be further reduced.

  Moreover, in each aperture | diaphragm | squeeze part shown in FIG. 3, FIG. 18-22, although each slit plate is comprised with the single material, not only this but each slit plate is comprised combining different materials. Thus, the configuration may be such that the transmitted dose of the radiation X decreases as the distance from the peripheral edge of the opening region 51 increases.

  As an example of the form in this case, the composition ratio of the element having the radiation shielding ability such as lead, tungsten, molybdenum and the like and the element not having the radiation shielding ability is blended, and the blending ratio is set to the periphery of the opening region 51. The form comprised by changing according to the distance from a part can be illustrated. In this case, the element may be constituted by kneading a single element of an element having radiation shielding ability or a compound thereof into a resin material not having radiation shielding ability. In this case, the moldability is improved and the weight can be reduced, which is preferable.

  Moreover, in the above-mentioned aperture | diaphragm | squeeze part, although the shape of planar view of the edge part which each slit plate opposes is made into a linear form, it is good also as a form which makes the said shape into a curvilinear form.

  Further, in each of the above embodiments, the case where the present invention is applied to the treatment in which the catheter 60 is inserted into the body from the neck of the patient 14 has been described. However, the present invention is not limited to this. It goes without saying that the present invention may be applied to a treatment in which the catheter 60 is inserted into the body from other parts such as the base of the thigh or the armpit.

Moreover, although the said embodiment demonstrated the case where the aperture | diaphragm | squeeze part 44 restrict | limits the irradiation area | region of the direct line | wire of the radiation X to a region of interest, this invention is not limited to this. For example, female gonads and fetuses are susceptible to radiation and are vulnerable to exposure. Further, since the medical equipment used in a human body and the integral of such pacemakers semiconductor is used and characteristics deteriorates by irradiation, it is preferable to suppress the exposure. Therefore, the irradiation apparatus control unit 140 acquires information on a region where exposure should be suppressed, such as a region susceptible to radiation, such as a female gonad or fetus, or a region embedded with a medical device used integrally with the human body. However, the diaphragm unit 44 may be controlled so that the radiation that has passed through the diaphragm unit 44 is irradiated to the region where exposure is to be suppressed. Information related to the area where exposure should be suppressed may be input from the operation panel 112, may be transferred from an external device via a network, or may be various types such as pattern matching from a captured radiographic image. It may be specified by image processing.

In the above-described embodiment, the case where the irradiation region of the direct line of the radiation X is limited to the region of interest by the diaphragm 44 when performing the IVR has been described, but the present invention is not limited to this. . There is the case of the pre-shooting in order to carry out the Pojishi ® two-ring before carrying out the present photographing, such as IVR. In such pre-imaging, the irradiation area of the direct line of the radiation X may be limited by the diaphragm 44. For example, the daily exposure dose for each region such as the chest, abdomen, and buttocks is stored for each patient in a database of an external server such as an RIS server, and the imaging target is taken from the information stored in the database. Find the total value of the exposure dose in a predetermined period for each region of the patient (for example, the last three months), and in the pre-shooting for positioning, the exposure dose is large in the vicinity of the region to be imaged this time, When there is a region where the exposure dose exceeds a predetermined allowable threshold value, the radiation that has passed through each of the slit plates 4 4 A to 4 D is not irradiated with the direct line of the radiation X to the region exceeding the threshold value. The diaphragm 44 may be controlled so that X is irradiated. As a result, it is possible to suppress further exposure of a part that has already been exposed to a large amount even in pre-imaging. It should be noted that the same control may be performed in actual photographing such as IVR.

  In each of the above embodiments, the CPU 114 of the console 26 has been described with reference to an example in which the radiographic image capturing process and the position specifying process are performed. However, the present invention is not limited to this, for example, The irradiation device control unit 140 of the radiation irradiation device 18 or the cassette control unit 100 of the electronic cassette 20 may execute these processes.

  In addition, it is needless to say that the configuration (see FIGS. 1 to 6) of the imaging system 10 described in the above embodiments is an example, and can be changed without departing from the gist of the present invention.

  Further, the flow of the radiographic image capturing processing program (see FIGS. 11 and 17) and the position specifying processing program described in each of the above embodiments is also an example, and is not necessary within the scope of the present invention. It goes without saying that steps can be deleted, new steps can be added, and the processing order can be changed.

  Further, in each of the above-described embodiments, the catheter 60 in the IVR is described as an example as a surgical instrument and a medical instrument to be inserted into the body of the patient 14, but other surgical procedures and medical instruments (guidewire, fracture in the IVR) are described. Needless to say, the present invention can also be applied to screws, plates, intramedullary nails, etc. in treatment.

DESCRIPTION OF SYMBOLS 10 Radiographic imaging system 14 Patient 18 Radiation irradiation apparatus 20 Electronic cassette 22 Support member 26 Console 28 Display 28A Display surface 36 Radiation detector 36A Irradiation surface 42 Radiation sources 43, 44, 44 ', 46, 48, 50 44D Slit plates 46A-46D Slit plates 48A-48D Slit plates 50A-50D Slit plate group 51 Opening region 60 Catheter 114 CPU
146, 148, 150, 152 Motor

Claims (14)

A calculation means for calculating a cumulative exposure dose from the time when radiation treatment applied to a subject from a radiation source is started for capturing a radiographic image;
Limiting means for limiting the exposure amount to the irradiation field excluding the region of interest of radiation by the radiation source,
Determination means for determining whether or not the cumulative exposure amount calculated by the calculation means reaches a predetermined exposure amount;
Control means for controlling the limiting means so as to add the restriction when it is determined by the determining means that the cumulative exposure amount reaches a predetermined exposure amount;
A radiation control apparatus comprising: The radiation control apparatus according to claim 1, wherein the calculation unit calculates a cumulative exposure dose with respect to the irradiation field from a time point when the treatment is started to a time point when the moving image capturing ends as the cumulative exposure dose. The restricting means is provided between the radiation source and the subject, and has an aperture region configured to allow a part of the radiation emitted from the radiation source to pass therethrough and to change the area. With
The radiation control apparatus according to claim 1, wherein the control unit controls the diaphragm so as to add the restriction by changing an area of an opening region of the diaphragm. The radiation control apparatus according to claim 3, wherein the aperture is configured such that a radiation transmission dose decreases as the distance from the peripheral edge of the opening region increases. The radiation control apparatus according to any one of claims 1 to 4, wherein the calculation means calculates the cumulative exposure dose for each segmented area defined as a predetermined unit area in the irradiation field. The radiation control apparatus according to any one of claims 1 to 5, wherein the control unit performs the control following a region of interest that changes over time. Further comprising a specifying means for specifying a position of a predetermined part of the medical instrument inserted into the subject,
The radiation control apparatus according to claim 6, wherein the control unit performs the control using the position specified by the specifying unit as the region of interest. The specifying means is determined in advance by at least one of image recognition based on image information obtained by moving image shooting, an IC tag provided in the predetermined part, and a magnetic body provided in the part. The radiation control apparatus according to claim 7, wherein the position of the selected part is specified. The radiation control apparatus according to any one of claims 1 to 8,
A radiographic image capturing apparatus that performs moving image capturing of a radiographic image indicated by the radiation emitted from a radiation source that emits radiation to be controlled by the radiation control apparatus and transmitted through the subject;
Including radiographic imaging system. Configuration wherein the radiographic image capturing apparatus, the phosphor layer to generate light by the radiation is irradiated, and board of photoelectric conversion elements are formed for converting the light generated in the phosphor layer to the charge is stacked is equipped with a radiation detector of the indirect conversion type radiation image capturing system according to claim 9 Symbol mounting for movie shooting by the radiation detector. The radiographic imaging system according to claim 10, wherein the phosphor layer contains CsI. The radiographic imaging system according to claim 10 or 11, wherein the radiation detector is arranged in the radiographic imaging apparatus so that radiation enters from the substrate side. The radiation control apparatus according to any one of claims 1 to 8,
A radiation source for emitting radiation to be controlled by the radiation control device;
Including radiographic imaging system. The radiation control apparatus according to any one of claims 1 to 8,
A radiographic image capturing apparatus that performs moving image capturing of a radiographic image indicated by the radiation emitted from a radiation source that emits radiation to be controlled by the radiation control apparatus and transmitted through the subject;
The radiation source;
Including radiographic imaging system.