Detector module, x-ray computer tomographic device, and x-ray detecting device

Abstract

To prevent the generation of arc discharge.SOLUTION: A detector module according to an embodiment is provided with a direct conversion type semiconductor crystal, a first electrode that is provided on a radiation incident surface of the semiconductor crystal; and a plurality of second electrodes that are provided opposite to the first electrode across the semiconductor crystal. The first electrode is divided with respect to at least a channel direction into a first partial electrode and a second partial electrode which are each independently applied with high voltage.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The embodiments disclosed in this specification and the drawings relate to a detector module, an X-ray computed tomography apparatus, and an X-ray detection apparatus. [Background technology]

[0002] A high-voltage electrode is attached to the X-ray incident surface of the direct conversion semiconductor crystal, and pixel electrodes of the high-voltage electrode are attached across the semiconductor crystal. A high voltage is applied to the high-voltage electrode. The high-voltage electrode is divided in the column direction to improve the current supply capacity to the semiconductor crystal and to make it easier to attach to the semiconductor crystal.

[0003] When X-rays are incident on a semiconductor crystal, an amount of charge corresponding to the flux of the incident X-rays is generated in the semiconductor crystal. If a large flux of X-rays is instantaneously incident on the semiconductor crystal and an amount of charge is generated that exceeds the current supply capacity of the high-voltage electrodes to the semiconductor crystal, the voltage applied to the high-voltage electrodes will drop. If a voltage drop occurs, there is a risk of arc discharge occurring between adjacent high-voltage electrodes. If an arc discharge occurs, there is a risk of the high-voltage electrodes failing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-18154 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-279653 [Patent Document 3] Special Publication No. 2009-530792 Summary of the Invention [Problem to be solved by the invention]

[0005] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to suppress the occurrence of arc discharge. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described below can also be positioned as other problems. [Means for solving the problem]

[0006] A detector module according to an embodiment includes a direct conversion type semiconductor crystal, a first electrode provided on the radiation incident surface side of the semiconductor crystal, the first electrode having a first partial electrode and a second partial electrode to which a high voltage is applied independently and which are divided in the channel direction and / or column direction, a plurality of second electrodes provided opposite the first electrode across the semiconductor crystal, a detection unit that detects incidence of radiation of a predetermined flux on the first partial electrode, and a control unit that controls the high voltage applied to the second partial electrode when incidence of radiation of the predetermined flux is detected. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of the arrangement of an X-ray computed tomography apparatus according to the first embodiment. [Figure 2] FIG. 2 is a perspective view showing a schematic structure of the X-ray detection device. [Figure 3] FIG. 3 is a perspective view showing a schematic structure of the detector module. [Figure 4] FIG. 4 is a plan view of the X-ray detection layer shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view of the X-ray detection layer shown in FIG. [Figure 6] FIG. 6 is a diagram showing an example of the configuration of a power control system related to high-voltage electrodes. [Figure 7] FIG. 7 is a diagram schematically showing a change in voltage when a large flux of X-rays is incident on an X-ray detection layer having high-voltage electrodes divided in the column direction. [Figure 8]FIG. 8 is a diagram schematically showing a change in voltage when a large flux of X-rays is incident on an X-ray detection layer having high-voltage electrodes divided in the channel direction. [Figure 9] FIG. 9 is a diagram showing an example of an X-ray detection layer having high-voltage electrodes divided into a checkerboard pattern. [Figure 10] FIG. 10 is a diagram illustrating an example of the configuration of a power control system for a high-voltage electrode according to Example 1 of the second embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of high voltage control by voltage monitoring according to the first embodiment. [Figure 12] FIG. 12 is a diagram illustrating an example of high voltage control by current monitoring according to the first embodiment. [Figure 13] FIG. 13 is a diagram showing an example of the configuration of an X-ray computed tomography apparatus according to Example 2 of the second embodiment. [Figure 14] FIG. 14 is a diagram illustrating an example of the configuration of a power control system for a high-voltage electrode according to Example 2 of the second embodiment. [Figure 15] FIG. 15 is a diagram illustrating an example of high voltage control according to Example 2 of the second embodiment. [Figure 16] FIG. 16 is a diagram illustrating a configuration example of a power control system for a high-voltage electrode according to Example 3 of the second embodiment. [Figure 17] FIG. 17 is a diagram illustrating an example of high voltage control according to Example 3 of the second embodiment. [Figure 18] FIG. 18 is a diagram showing an example of an arrangement of detector modules according to the third embodiment. [Figure 19] FIG. 19 is a diagram illustrating an example of the configuration of a power control system for a detector module according to the third embodiment. [Figure 20] FIG. 20 is a diagram schematically illustrating an example of high voltage control according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of a detector module, an X-ray computed tomography apparatus, and an X-ray detection apparatus will be described in detail with reference to the drawings. In the following description, components having the same or substantially the same functions as those described above with reference to the previous drawings will be assigned the same reference numerals and will be described only if necessary. Furthermore, even when the same parts are shown, the dimensions and proportions may be different depending on the drawing.

[0009] There are various types of X-ray computed tomography apparatuses (X-ray CT apparatuses), such as third-generation CT and fourth-generation CT, and any of these types can be applied to this embodiment. Here, the third-generation CT is a rotate / rotate-type in which the X-ray tube and detector rotate together around the subject. The fourth-generation CT is a stationary / rotate-type in which a large number of X-ray detection elements arranged in a ring shape are fixed, and only the X-ray tube rotates around the subject.

[0010] (First embodiment) FIG. 1 is a diagram showing an example of the configuration of an X-ray computed tomography apparatus 1 according to the first embodiment. As shown in FIG. 1, the X-ray computed tomography apparatus 1 includes a gantry 10, a bed 30, and a console 40. Although FIG. 1 illustrates multiple gantry 10s for ease of explanation, the apparatus may actually include one or multiple gantry 10s. The gantry 10 is a scanning device configured to perform X-ray CT scans of a subject P. The bed 30 is a transport device on which the subject P to be scanned for X-ray CT scans is placed and which positions the subject P. The console 40 is a computer that controls the gantry 10. For example, the gantry 10 and the bed 30 are installed in a CT examination room, and the console 40 is installed in a control room adjacent to the CT examination room. The gantry 10, the bed 30, and the console 40 are connected to each other by wire or wirelessly so that they can communicate with each other. The console 40 does not necessarily have to be installed in the control room. For example, the console 40 may be installed in the same room as the gantry 10 and the bed 30. The console 40 may also be incorporated into the cradle 10 .

[0011] As shown in FIG. 1, the gantry 10 includes an X-ray tube 11, an X-ray detector 12, a rotating frame 13, an X-ray high voltage device 14, a control device 15, a wedge 16, a collimator 17, and a data acquisition system (DAS) 18.

[0012] The X-ray tube 11 irradiates the subject P with X-rays. Specifically, the X-ray tube 11 includes a cathode that generates thermoelectrons, an anode that generates X-rays upon receiving thermoelectrons flying from the cathode, and a vacuum tube that holds the cathode and anode. The X-ray tube 11 is connected to the X-ray high voltage device 14 via a high-voltage cable. A tube voltage is applied between the cathode and the anode by the X-ray high voltage device 14. The application of the tube voltage causes thermoelectrons to fly from the cathode toward the anode. A tube current flows as the thermoelectrons fly from the cathode toward the anode. X-rays are generated when the thermoelectrons collide with the anode.

[0013] The X-ray detector 12 detects the X-rays emitted from the X-ray tube 11 and passing through the subject P in photon units, and outputs an electrical signal having a pulse height corresponding to the number of incident X-ray photons to the DAS 18. The X-ray detector 12 has a structure in which, for example, a plurality of pixel rows are arranged in the slice direction (row direction), with a plurality of detector pixels arranged in the channel direction along an arc centered on the focal point of the X-ray tube 11. The channel direction and the row direction are orthogonal to each other. The X-ray detector 12 is a direct conversion type detector.

[0014] The rotating frame 13 is an annular frame that supports the X-ray tube 11 and the X-ray detector 12 rotatably around a rotation axis (Z-axis). Specifically, the rotating frame 13 supports the X-ray tube 11 and the X-ray detector 12 so that they face each other. In addition to the X-ray tube 11 and the X-ray detector 12, the rotating frame 13 also supports the X-ray high-voltage generator 14 and the DAS 18. The rotating frame 13 is supported on a fixed frame (not shown) so that it can rotate around the rotation axis. The rotation mechanism includes, for example, a motor that generates a rotational driving force and a bearing that transmits the rotational driving force to the rotating frame 13 to rotate it. The motor is provided on the fixed frame, and the bearing is physically connected to the rotating frame 13 and the motor, so that the rotating frame 13 rotates in response to the rotational force of the motor. The rotation of the rotating frame 13 around the rotation axis causes the X-ray tube 11 and the X-ray detector 12 to rotate around the rotation axis. The rotating frame 13 is an example of a rotating unit.

[0015] This embodiment is applicable to supine CT and / or upright CT. In the case of supine CT, the longitudinal direction of the rotation axis of the rotating frame 13 or the top board 33 of the bed 30 in a non-tilted state is defined as the Z-axis direction, the axial direction perpendicular to the Z-axis direction and horizontal to the floor surface is defined as the X-axis direction, and the axial direction perpendicular to the Z-axis direction and perpendicular to the floor surface is defined as the Y-axis direction. In the case of application only to upright CT or to both supine CT and upright CT, the longitudinal direction of the rotation axis of the rotating frame 13 in a non-tilted state is defined as the Z-axis direction, the direction perpendicular to the Z-axis direction and from the center of rotation toward the support column supporting the rotating frame 13 is defined as the X-axis direction, and the direction perpendicular to the Z-axis direction and the X-axis direction is defined as the Y-axis direction.

[0016] The X-ray high voltage device 14 has a high voltage generator and an X-ray control device. The high voltage generator has electrical circuits such as a transformer and a rectifier, and generates a high voltage to be applied to the X-ray tube 11 and a filament current to be supplied to the X-ray tube 11. The X-ray control device controls the output voltage according to the X-rays emitted by the X-ray tube 11. The high voltage generator may be of a transformer type or an inverter type. The X-ray high voltage device 14 may be provided on the rotating frame 13 in the gantry 10, or on a fixed frame (not shown) in the gantry 10.

[0017] The wedge 16 adjusts the dose of X-rays irradiated onto the subject P. Specifically, the wedge 16 attenuates the X-rays so that the dose of X-rays irradiated from the X-ray tube 11 onto the subject P has a predetermined distribution. For example, the wedge 16 is made of a metal plate such as aluminum, such as a wedge filter or a bow-tie filter.

[0018] The collimator 17 limits the irradiation range of the X-rays that have passed through the wedge 16. The collimator 17 slidably supports multiple lead plates that shield the X-rays, and adjusts the shape of the slits formed by the multiple lead plates. The collimator 17 is sometimes called an X-ray aperture.

[0019] The data acquisition circuitry 18 processes the electrical signals from the X-ray detector 12 and counts the number of X-ray photons for each view. The data acquisition circuitry 18 collects count data having digital values ​​representing the number of photons for each view. The count data is also called detection data. The data acquisition circuitry 18 is realized, for example, by an application specific integrated circuit (ASIC) equipped with circuit elements capable of generating count data. The count data is transmitted to the console 40 via a non-contact data transmission device or the like.

[0020] In this embodiment, the photon counting type X-ray detector 12 and data acquisition circuit 18 are described as examples, but the technology according to this embodiment can also be applied to an integral type X-ray detector and data acquisition circuit.

[0021] The rotating frame 13 and the fixed frame are each provided with a non-contact or contact communication circuit, and these communication circuits enable communication between the units supported on the rotating frame 13 and devices external to the fixed frame or gantry 10. For example, if optical communication is used as the non-contact communication method, the detection data generated by the DAS 18 is transmitted by optical communication from a transmitter having a light-emitting diode (LED) provided on the rotating frame 13 to a receiver having a photodiode provided on the fixed frame of the gantry 10, and the data is then transferred from the fixed frame to the console 40 by the transmitter. Note that, other communication methods may also be used, such as non-contact data transmission methods such as capacitive coupling and radio wave methods, as well as contact data transmission methods using slip rings and electrode brushes.

[0022] The control device 15 controls the X-ray high-voltage generator 14 and the data acquisition circuit 18 to perform X-ray CT imaging in accordance with the imaging control function 441 of the processing circuit 44 of the console 40. The control device 15 includes a processing circuit having a central processing unit (CPU) or a microprocessing unit (MPU), etc., and a drive mechanism such as a motor and an actuator. The processing circuit includes, as hardware resources, a processor such as a CPU and memory such as a read-only memory (ROM) or a random-access memory (RAM). The control device 15 executes various functions using a processor that executes programs loaded in the memory. Note that various functions are not limited to being implemented by a single processing circuit. A processing circuit may be configured by combining multiple independent processors, and each processor may execute a program to implement each function. The control device 15 may also be implemented using an ASIC or a field programmable gate array (FPGA). Furthermore, the control device 15 may be realized by other complex programmable logic devices (CPLDs) or simple programmable logic devices (SPLDs).

[0023] The control device 15 has a function of receiving input signals from an input interface 43 (described later) attached to the console 40 or the gantry 10 and controlling the operation of the gantry 10 and the bed 30. For example, the control device 15 receives input signals and controls the rotation of the rotating frame 13, the tilt of the gantry 10, and the operation of the bed 30 and the tabletop 33. The control of tilting the gantry 10 is realized by the control device 15 rotating the rotating frame 13 around an axis parallel to the X-axis direction based on inclination angle (tilt angle) information input via an input interface attached to the gantry 10. The control device 15 may be provided in the gantry 10 or in the console 40.

[0024] The bed 30 includes a base 31, a support frame 32, a top plate 33, and a bed driving device 34. The base 31 is placed on the floor. The base 31 is a housing that supports the support frame 32 so that it can move vertically (in the Y-axis direction) relative to the floor. The support frame 32 is a frame provided on top of the base 31. The support frame 32 supports the top plate 33 so that it can slide along the rotation axis (Z-axis). The top plate 33 is a flexible plate on which the subject P is placed.

[0025] The bed driving device 34 is housed in the housing of the bed 30. The bed driving device 34 is a motor or actuator that generates power to move the support frame 32 on which the subject P is placed and the tabletop 33. The bed driving device 34 operates under the control of the console 40 or the like.

[0026] The console 40 has a memory 41, a display 42, an input interface 43, and a processing circuit 44. Data communication between the memory 41, the display 42, the input interface 43, and the processing circuit 44 is performed via a bus (BUS). Note that although the console 40 will be described as being separate from the gantry 10, the gantry 10 may include the console 40 or some of the components of the console 40.

[0027] The memory 41 is a storage device such as a hard disk drive (HDD), a solid state drive (SSD), or an integrated circuit storage device that stores various information. In addition to an HDD or SSD, the memory 41 may be a portable storage medium such as a compact disc (CD), a digital versatile disc (DVD), a Blu-ray (registered trademark) disc (BD), or a flash memory. The memory 41 may also be a drive device that reads and writes various information from and to a semiconductor memory element such as a flash memory or a RAM. The storage area of ​​the memory 41 may be located within the X-ray computed tomography apparatus 1 or in an external storage device connected via a network. The memory 41 stores, for example, projection data and reconstructed image data.

[0028] The display 42 displays various types of information. For example, the display 42 outputs CT images generated by the processing circuitry 44, a GUI (Graphical User Interface) for receiving various operations from the operator, and the like. Any of a variety of displays can be used as the display 42, as appropriate. For example, the display 42 can be a liquid crystal display (LCD), a cathode ray tube (CRT) display, an organic electroluminescence display (OLED), or a plasma display.

[0029] The display 42 may be installed anywhere in the control room. Alternatively, the display 42 may be installed on the pedestal 10. The display 42 may be a desktop type, or may be configured as a tablet terminal or the like capable of wireless communication with the main body of the console 40. Alternatively, one or more projectors may be used as the display 42.

[0030] The input interface 43 accepts various input operations from the operator, converts the accepted input operations into electrical signals, and outputs the electrical signals to the processing circuitry 44. For example, the input interface 43 accepts from the operator acquisition conditions for acquiring projection data, reconstruction conditions for reconstructing CT images, and image processing conditions for generating post-processed images from CT images. Examples of the input interface 43 that can be used include a mouse, keyboard, trackball, switch, button, joystick, touchpad, and touch panel display, as appropriate. Note that in this embodiment, the input interface 43 is not limited to a device equipped with physical operation components such as a mouse, keyboard, trackball, switch, button, joystick, touchpad, and touch panel display. For example, an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the device and outputs the electrical signal to the processing circuitry 44 is also included as an example of the input interface 43. The input interface 43 may also be provided on the gantry 10. The input interface 43 may also be configured as a tablet terminal or the like capable of wireless communication with the console 40.

[0031] The processing circuitry 44 controls the overall operation of the X-ray computed tomography apparatus 1 in response to electrical signals of input operations output from the input interface 43. The processing circuitry 44 generates image data based on electrical signals output from the X-ray detector 12. For example, the processing circuitry 44 has, as hardware resources, a processor such as a CPU, MPU, or GPU, and memories such as ROM and RAM. The processing circuitry 44 executes an imaging control function 441, a reconstruction function 442, an image processing function 443, a display control function 444, etc., by a processor that executes programs loaded in the memory.

[0032] Note that each of the functions 441-444 does not necessarily have to be realized by a single processing circuit, but may be realized by combining a plurality of independent processors to form a processing circuit, and each processor may execute a program to realize each of the functions 441-444.

[0033] In the imaging control function 441, the processing circuitry 44 controls the X-ray high-voltage generator 14, the control device 15, and the DAS 18 in accordance with imaging conditions to perform X-ray CT imaging. In the reconstruction function 442, the processing circuitry 44 performs preprocessing such as logarithmic conversion, offset correction, inter-channel sensitivity correction, and beam hardening correction on the count data output from the DAS 18. The processing circuitry 44 performs reconstruction processing using filtered back projection, iterative reconstruction, machine learning, or the like on the preprocessed count data to generate a CT image. In the image processing function 443, the processing circuitry 44 converts the CT image generated by the reconstruction function 442 into a cross-sectional image of an arbitrary cross section or a rendering image of an arbitrary viewpoint direction. The conversion is performed based on an input operation received from the operator via the input interface 43. For example, the processing circuitry 44 performs three-dimensional image processing such as volume rendering, surface volume rendering, pixel value projection processing, MPR (Multi-Planer Reconstruction) processing, and CPR (Curved MPR) processing on the CT image data to generate a rendered image in an arbitrary viewpoint direction. Note that the generation of a rendered image in an arbitrary viewpoint direction may be performed directly by the reconstruction function 442. In the display control function 444, the processing circuitry 44 displays various images generated by the image processing function 443 on the display 42. For example, a CT image, a cross-sectional image of an arbitrary cross section, a rendered image in an arbitrary viewpoint direction, a setting screen for imaging conditions, etc. are displayed on the display 42.

[0034] Although the console 40 has been described as a single console that executes multiple functions, multiple functions may be executed by separate consoles. The processing circuitry 44 is not limited to being included in the console 40, but may also be included in an integrated server that collectively processes projection data acquired by multiple medical image diagnostic devices. Post-processing may be performed by either the console 40 or an external workstation. Furthermore, processing may be performed simultaneously by both the console 40 and the workstation.

[0035] The overall configuration of the X-ray computed tomography apparatus 1 according to this embodiment has been described above. Next, the X-ray detection apparatus according to this embodiment will be described in detail. The X-ray detection apparatus according to this embodiment is a mechanical device including an X-ray detector 12 and a DAS 18.

[0036] Fig. 2 is a perspective view showing a schematic structure of an X-ray detection device 50. For example, as shown in Fig. 2, the X-ray detection device 50 has a detector module 51, a collimator 52, a first fixing frame 53, a second fixing frame 54, a first support frame 55, a second support frame 56, and a light shielding plate 57. The direction perpendicular to the channel direction and the column direction is called the thickness direction.

[0037] The detector module 51 is a mechanical module including the X-ray detector 12 and the DAS 18. In the X-ray detection device 50, a plurality of detector modules 51 are arranged along the channel direction.

[0038] The collimator 52 is configured by arranging multiple collimator plates in a grid pattern, and limits the solid angle of X-rays incident on each detector pixel of each detector module 51. Specifically, the collimator 52 removes scattered X-rays scattered by various structures so that only direct X-rays are incident on each detector pixel. The collimator 52 is formed in a substantially arc shape along the channel direction, and is arranged so as to cover the X-ray detection layer 61 of each detector module 51.

[0039] The first and second fixing frames 53 and 54 fix the positions of the detector modules 51 so that the detector modules 51 are aligned in the channel direction. The first and second support frames 55 and 56 support the collimator 52, the first and second fixing frames 53, and the second fixing frames 54. Specifically, the first and second support frames 55 and 56 support the collimator 52, the first and second fixing frames 53, and the second fixing frames 54 so as to sandwich them from both sides in the column direction. The light shielding plate 57 reduces light incident on the X-ray detection layer 61 of the detector module 51. For example, the light shielding plate 57 is a member formed in a thin plate shape using a material capable of reducing light. The light shielding plate 57 is attached to the first and second support frames 55 and 56 so as to cover the entire collimator 52.

[0040] FIG. 3 is a perspective view showing a schematic structure of the detector module 51. As shown in FIG. 3, the detector module 51 includes an X-ray detection layer 61, a support base 62, a control board 63, a module control circuit 64, and a DAS circuit 65. The X-ray detection layer 61 includes a plurality of detector pixels 70 arranged in the channel direction and the column direction. Each detector pixel 70 detects incident X-rays. The X-ray detection layers 61 provided in each of the detector modules 51 constitute the X-ray detector 12. The support base 62 is a structure that supports the X-ray detection layer 61 having the plurality of detector pixels 70. The control board 63 is connected to the support base 62. The control board 63 is provided with a module control circuit 64 and a DAS circuit 65. The module control circuit 64 is an integrated circuit that controls the electrical system provided in the X-ray detection layer 61. The DAS circuit 65 is an integrated circuit that collects count data via each detector pixel 70 included in the X-ray detection layer 61. The DAS 18 is formed by the plurality of DAS circuits 65 provided in each of the detector modules 51.

[0041] Fig. 4 is a plan view of the X-ray detection layer 61 shown in Fig. 3, and Fig. 5 is a cross-sectional view of the X-ray detection layer 61 shown in Fig. 3. Note that Fig. 4 is a plan view seen from the X-ray tube 11 to the X-ray detection device 50, and Fig. 5 is a cross-sectional view of a two-dimensional plane defined by the column direction and the channel direction.

[0042] As shown in FIG. 5 , the X-ray detection layer 61 includes a direct conversion semiconductor crystal 71. The semiconductor crystal 71 may be made of, for example, amorphous selenium, zinc iodide, cadmium telluride, cadmium zinc telluride, or any other semiconductor material. When X-rays are incident on the semiconductor crystal 71, an electric charge is generated according to the flux or number of photons of the incident X-rays. A high-voltage electrode 72 is provided on the X-ray incident surface of the semiconductor crystal 71. A high voltage is applied by a high-voltage application circuit (described later) to transfer the electric charge to a pixel electrode 73. The high-voltage application circuit supplies power to the semiconductor crystal 71 via the high-voltage electrode 72. A plurality of pixel electrodes 73 are provided facing the high-voltage electrode 72 across the semiconductor crystal 71. A DAS circuit 65 is connected to each pixel electrode 73 via a signal line. The DAS circuit 65 collects the electric charge generated in the semiconductor crystal 71 as a current signal via the pixel electrode 73. A support substrate 74 is provided facing the semiconductor crystal 71 with a plurality of pixel electrodes 73 interposed therebetween. The support base 62 shown in Fig. 3 is provided on the support substrate 74. One pixel electrode 73 corresponds to one detector pixel 70.

[0043] 4 and 5, the high-voltage electrode 72 according to this embodiment is divided into a plurality of partial electrodes 721, 722 in the channel direction. Specifically, the high-voltage electrode 72 is divided alternately into first partial electrodes 721 and second partial electrodes 722 along the channel direction. The first partial electrodes 721 and the second partial electrodes 722 are not divided in the column direction perpendicular to the channel direction. That is, the first partial electrodes 721 and the second partial electrodes 722 are provided so as to span a plurality of detector pixels 70 or pixel electrodes 73 in the column direction. High voltages are applied to the first partial electrodes 721 and the second partial electrodes 722 independently of each other.

[0044] 4, each of the partial electrodes 721, 722 is attached to the semiconductor crystal 71 so as to cover one detector pixel 70 or pixel electrode 73 in the channel direction. That is, the width of each of the partial electrodes 721, 722 in the channel direction corresponds to the width of one detector pixel 70 or pixel electrode in the channel direction. However, this embodiment is not limited to this. For example, the width of each of the partial electrodes 721, 722 in the channel direction may be designed to correspond to the widths of two or more detector pixels 70 or pixel electrodes in the channel direction.

[0045] 4, a terminal 723 is provided on the first partial electrode 721, and the terminal 723 is connected to a high-voltage application circuit via a signal line (not shown). Similarly, a terminal 724 is provided on the second partial electrode 722, and the terminal 724 is connected to a high-voltage application circuit via a signal line (not shown). A high voltage is applied to the first partial electrode 721 and the second partial electrode 722 independently of each other. A common high voltage is applied to the multiple first partial electrodes 721 that are spaced apart in the channel direction. Similarly, a common high voltage is applied to the multiple second partial electrodes 722 that are spaced apart in the channel direction.

[0046] 6 is a diagram showing an example of the configuration of a power control system for the high-voltage electrode 72. As shown in FIG. 6, a high-voltage application circuit 751 is connected to a first partial electrode 721 of the high-voltage electrode 72 via a signal line. A current / voltage detection element 761 is provided on the signal line connecting the first partial electrode 721 and the high-voltage application circuit 751. The high-voltage application circuit 751 and the current / voltage detection element 761 are each connected to the module control circuit 64 via a signal line. Similarly, a high-voltage application circuit 752 is connected to a second partial electrode 722 of the high-voltage electrode 72 via a signal line. A current / voltage detection element 762 is provided on the signal line connecting the second partial electrode 722 and the high-voltage application circuit 752. The high-voltage application circuit 752 and the current / voltage detection element 762 are each connected to the module control circuit 64 via a signal line.

[0047] The high voltage application circuit 751 applies a high voltage to the first partial electrode 721 under the control of the module control circuit 64. The high voltage is also called a bias voltage. The current / voltage detection element 761 detects the voltage applied to the first partial electrode 721 or the current supplied to the first partial electrode 721. The detected voltage is called the detected voltage, and the detected current is called the detected current. The detected voltage or detected current is supplied to the module control circuit 64 as an analog signal or a digital signal. Similarly, the high voltage application circuit 752 applies a high voltage to the second partial electrode 722 under the control of the module control circuit 64. The current / voltage detection element 762 detects the voltage applied to the second partial electrode 722 or the current supplied to the second partial electrode 722. The detected voltage or detected current is supplied to the module control circuit 64 as an analog signal or a digital signal.

[0048] The module control circuit 64 is realized by an analog or digital control circuit. The module control circuit 64 individually controls the high-voltage application circuits 751 and 752 to apply high voltages to the partial electrodes 721 and 722 independently. Specifically, the module control circuit 64 applies a set high voltage to the first partial electrode 721 in accordance with feedback control based on the detected current / voltage from the current / voltage detection element 761 and the target current / voltage. Similarly, the module control circuit 64 applies a set high voltage to the second partial electrode 722 in accordance with feedback control based on the detected current / voltage from the current / voltage detection element 762 and the target current / voltage. The set values ​​of the voltages applied to the first partial electrode 721 and the second partial electrode 722 are set to the same value. Additionally, the module control circuit 64 can control the high-voltage application circuits 751 and 752 to switch the polarity of the high voltage applied to the partial electrodes 721 and 722.

[0049] Here, the collection of electrical signals by the detector pixel 70 will be described. When X-rays are incident on the semiconductor crystal 71, charges are generated in a number proportional to the flux, X-ray dose, or number of photons of the incident X-rays. In the following description, the term "flux" will be used unless there is a particular physical need to distinguish between flux, X-ray dose, and number of photons. Charges are attracted to the pixel electrode 73 by a high voltage (bias voltage) applied to the high-voltage electrodes 721 and 722. More specifically, electron-hole pairs are generated in the semiconductor crystal 71, and charges corresponding to the polarity of the high voltage applied to the high-voltage electrodes 721 and 722 are attracted to the pixel electrode 73. For example, when a negative high voltage is applied, electrons are attracted to the pixel electrode 73. The electrons attracted to the pixel electrode 73 are read out from the pixel electrode 73 by the DAS circuit 65 as a current signal having a pulse height corresponding to the incident flux.

[0050] As described above, the high-voltage electrodes 721, 722 according to this embodiment are divided in the channel direction into the first partial electrode 721 and the second partial electrode 722. By dividing the high-voltage electrodes 721, 722, it is possible to improve the current supply capability of the detector pixel 70 compared to when there is a single high-voltage electrode.

[0051] Here, the advantages of dividing the high-voltage electrode 72 in the channel direction will be described. In addition to dividing the high-voltage electrode 72 in the column direction, dividing it in the channel direction is also possible. The difference between these two division modes becomes apparent when a large flux of X-rays is incident on the X-ray detection device 50.

[0052] FIG. 7 is a diagram showing a change in voltage when a large flux of X-rays is incident on an X-ray detection layer having high-voltage electrodes 72 divided in the column direction. When X-rays are incident on a semiconductor crystal, charges proportional to the flux of the incident X-rays are generated in the semiconductor crystal. When a large flux of X-rays exceeding the charge generation capacity of the semiconductor crystal is instantaneously incident, the semiconductor crystal becomes saturated, and charges proportional to the flux of the incident X-rays are not generated. Therefore, a current signal having a pulse height proportional to the flux of the incident X-rays cannot be collected from the pixel electrode. Furthermore, the saturation of the semiconductor crystal causes a drop in the value of the high voltage applied to the high-voltage electrode 72.

[0053] The skull, which has high X-ray absorption, is located at the end of the human body at the top of the head. When such a region is the imaging region, a large difference in the flux of incident X-rays between adjacent regions occurs, i.e., a flux step occurs. When the high-voltage electrode is divided in the column direction, a large flux of X-rays is not incident on the semiconductor crystal region corresponding to the second partial electrode 722 located at the bottom in the column direction, but a large flux of X-rays is momentarily incident on the semiconductor crystal region corresponding to the first partial electrode 721 located at the top in the column direction. When a large flux of X-rays is incident on the first partial electrode 721, a voltage drop occurs on the first partial electrode 721. However, because the first partial electrode 721 and the second partial electrode 722 are electrically separate systems, no voltage drop occurs on the second partial electrode 722. When a voltage drop occurs only on the first partial electrode 721, a voltage difference occurs between the first partial electrode 721 and the second partial electrode 722, and an arc discharge occurs between the first partial electrode 721 and the second partial electrode 722. If an arc discharge occurs, there is a risk that the first partial electrode 721 and the second partial electrode 722 may be damaged.

[0054] 8 is a diagram schematically showing a change in voltage when a high-flux X-ray is incident on an X-ray detection layer having a high-voltage electrode 72 divided in the channel direction. When the high-voltage electrode 72 is divided in the channel direction as shown in FIG. 8, the first partial electrode 721 and the second partial electrode 722 are both located at the same column position, and therefore, there is little risk that a high-flux X-ray will be incident on only one of the first partial electrode 721 and the second partial electrode 722. When a high-flux X-ray is incident on both the first partial electrode 721 and the second partial electrode 722, a voltage drop occurs in both the first partial electrode 721 and the second partial electrode 722. Therefore, no voltage difference occurs between the first partial electrode 721 and the second partial electrode 722, and the occurrence of arc discharge is suppressed.

[0055] As described above, by dividing the high-voltage electrode 72 in the channel direction, it is possible to suppress the occurrence of arc discharge even when a large flux step occurs, thereby reducing or preventing failures of the detector module 51 and the high-voltage electrode 72.

[0056] The manner in which the high-voltage electrode 72 is divided is not limited to the above. If the high-voltage electrode 72 is divided at least in the channel direction, it is possible to reduce the occurrence of arc discharge due to a step in the flux.

[0057] FIG. 9 is a diagram showing an example of an X-ray detection layer having a high-voltage electrode 72 divided into a checkerboard pattern (checkered tile). As shown in FIG. 9, the checkerboard-shaped high-voltage electrode 72 has first partial electrodes 721 and second partial electrodes 722 that are divided alternately in both the channel direction and the column direction. The first partial electrodes 721 and the second partial electrodes 722 are connected to each other via signal lines (not shown). Note that while FIG. 9 illustrates two detector pixels or pixel electrodes in the channel direction, three or more detector pixels or pixel electrodes are arranged in the channel direction. Accordingly, the first partial electrodes 721 and the second partial electrodes 722 are arranged alternately in the channel direction. Also, in FIG. 9, one first partial electrode 721 and one second partial electrode 722 cover two detector pixels or pixel electrodes in the column direction and one detector pixel in the channel direction, but the combination of the number in the column direction and the number in the channel direction is not particularly limited.

[0058] The checkered high-voltage electrode 72 is divided in the channel direction, so that both the first partial electrode 721 and the second partial electrode 722 are arranged at the same column position. There is little chance that a high-flux X-ray will be incident on only one of the first partial electrode 721 and the second partial electrode 722. Therefore, even if a flux step occurs in the column direction, there is little chance that a high-flux X-ray will be incident on only one of the first partial electrode 721 and the second partial electrode 722. Furthermore, there is little chance that the checkered high-voltage electrode 72 is divided in the column direction as well, so that both the first partial electrode 721 and the second partial electrode 722 are arranged at the same channel position. Therefore, even if a flux step occurs in the channel direction, there is little chance that a high-flux X-ray will be incident on only one of the first partial electrode 721 and the second partial electrode 722. Therefore, the occurrence of arc discharge can be further suppressed, and in turn, breakdowns in the detector module 51 and the high-voltage electrode 72 can be further reduced or prevented.

[0059] (Second embodiment) An X-ray computed tomography apparatus according to the second embodiment will be described below. The X-ray computed tomography apparatus according to the second embodiment reduces the occurrence of arc discharge by controlling the power to the high-voltage electrode 72. The manner in which the high-voltage electrode 72 according to the second embodiment is divided is not particularly limited, and can be divided in any of the channel direction, the column direction, and both the channel direction and the column direction.

[0060] Example 1 10 is a diagram showing an example of the configuration of a power control system for a high-voltage electrode 72 according to Example 1 of the second embodiment. As shown in FIG. 10, a module control circuit 64 executes a feedback control function 641, a voltage / current change detection function 642, and a voltage drop control function 643.

[0061] In the feedback control function 641, the module control circuit 64 controls the high-voltage application circuits 751 and 752 to apply high voltages to the partial electrodes 721 and 722 independently. Specifically, the module control circuit 64 applies a set high voltage to the first partial electrode 721 in accordance with feedback control based on the detected current / detected voltage from the current / voltage detection element 761 and the target current / target voltage. Similarly, the module control circuit 64 applies a set high voltage to the second partial electrode 722 in accordance with feedback control based on the detected current / detected voltage from the current / voltage detection element 762 and the target current / target voltage. The set values ​​of the voltages applied to the first partial electrode 721 and the second partial electrode 722 are set to the same value. Additionally, the module control circuit 64 can control the high-voltage application circuits 751 and 752 to switch the polarity of the high voltage applied to the partial electrodes 721 and 722.

[0062] In the voltage / current change detection function 642, the module control circuit 64 detects incidence of X-rays at a predetermined flux on either the first partial electrode 721 or the second partial electrode 722. The predetermined flux is set to a flux that can cause a voltage drop large enough to cause arc discharge when X-rays of that flux are incident on the semiconductor crystal 71. The module control circuit 64 according to the first embodiment detects a change in the detected current / detected voltage from the current / voltage detection element 762. More specifically, the module control circuit 64 detects an increase in the detected current or a decrease in the detected voltage.

[0063] In the voltage drop control function 643, when it is detected that X-rays of a predetermined flux are incident on either the first partial electrode 721 or the second partial electrode 722, the module control circuit 64 controls the high voltage applied to the partial electrodes 721, 722 on which the incidence of X-rays of the predetermined flux is detected. When the voltage / current change detection function 642 detects a change in the detected current / detected voltage, the module control circuit 64 according to the first embodiment drops the high voltage applied to the partial electrodes 722, 721 different from the partial electrodes 721, 722 on which the change in the detected current / detected voltage is detected.

[0064] 11 is a diagram illustrating an example of high voltage control by voltage monitoring according to the first embodiment. As illustrated in FIG. 11, assume that a large flux of X-rays is incident on a semiconductor crystal region corresponding to the first partial electrode 721 at time T1. In this case, the voltage applied to the first partial electrode 721 begins to drop, and accordingly, the detected voltage of the first partial electrode 721 detected by the current / voltage detection element 761 also drops. The module control circuit 64 detects the drop in the detected voltage using the voltage / current change detection function 642, thereby detecting the drop in the applied voltage to the first partial electrode 721. The drop in the detected voltage may be detected by comparing a difference in detected voltage per unit time with a threshold value, comparing a time derivative of the detected voltage with a threshold value, or the like.

[0065] When a drop in the detected voltage is detected, the module control circuit 64 controls the high-voltage application circuit 752 using the voltage drop control function 643 to drop the voltage applied to the second partial electrode 722. In FIG. 11 , the start time T2 of the voltage drop control is delayed from the detection time T1 of the drop in the voltage applied to the first partial electrode 721; however, the start time T2 may coincide with the detection time T1. During the voltage drop control, the module control circuit 64 feedback-controls the high-voltage application circuit 752 so that the voltage applied to the second partial electrode 722 drops with time in the same manner as the drop in the voltage applied to the first partial electrode 721. For example, the module control circuit 64 can drop the voltage applied to the second partial electrode 722 with time in the same manner as the drop in the voltage applied to the first partial electrode 721 by setting a target voltage such that the target voltage drops in accordance with the detected voltage of the first partial electrode 721.

[0066] As described above, according to the first embodiment, a drop in the voltage applied to the first partial electrode 721 is considered to be an incidence event of high-flux X-rays. When a drop in the voltage applied to the first partial electrode 721 is detected, the module control circuit 64 drops the voltage applied to the second partial electrode 722. As a result, even if a voltage drop occurs in the first partial electrode 721 due to incidence of high-flux X-rays, the voltage drop in the second partial electrode 722 is also artificially applied, so that the voltage difference between the first partial electrode 721 and the second partial electrode 722 is unlikely to widen to the extent that an arc discharge occurs. Furthermore, by causing the voltage of the second partial electrode 722 to drop with a time change similar to that of the voltage drop in the first partial electrode 721, it is possible to further narrow the voltage difference between the first partial electrode 721 and the second partial electrode 722. This makes it possible to suppress the occurrence of an arc discharge.

[0067] 12 is a diagram illustrating an example of high voltage control by current monitoring according to the first embodiment. As illustrated in FIG. 12, at time T1, when a large flux of X-rays is incident on a semiconductor crystal region corresponding to the first partial electrode 721, the current supplied to the first partial electrode 721 begins to increase, and accordingly, the detected current of the first partial electrode 721 detected by the current / voltage detection element 761 also increases. The module control circuit 64 detects a drop in the voltage applied to the first partial electrode 721 by detecting the increase in the detected current using the voltage / current change detection function 642. The increase in the detected current may be detected by comparing a difference in the detected current per unit time with a threshold value, comparing a time derivative of the detected current with a threshold value, or the like.

[0068] When an increase in the detected current is detected, the module control circuit 64 controls the high-voltage application circuit 752 by the voltage drop control function 643 at time T2 to reduce the voltage applied to the second partial electrode 722. In this way, in the case of the current monitoring method, an increase in the current supplied to the first partial electrode 721 is regarded as an incidence event of high-flux X-rays, and when an increase in the current supplied to the first partial electrode 721 is detected, the module control circuit 64 reduces the voltage applied to the second partial electrode 722. As a result, even if a voltage drop occurs in the first partial electrode 721 due to incidence of high-flux X-rays, the voltage drop in the second partial electrode 722 is also artificially reduced, so that the voltage difference between the first partial electrode 721 and the second partial electrode 722 is unlikely to widen to a level that would cause arc discharge. This makes it possible to suppress the occurrence of arc discharge.

[0069] Example 2 13 is a diagram showing an example of the configuration of an X-ray computed tomography apparatus 2 according to Example 2 of the second embodiment. As shown in Fig. 13, the processing circuitry 44 of the X-ray computed tomography apparatus 2 executes an imaging control function 441, a reconstruction function 442, an image processing function 443, a display control function 444, and in addition, a prediction function 445.

[0070] In the prediction function 445, the processing circuitry 44 predicts the time at which X-rays with a predetermined flux are expected to be incident based on the scan plan. The predetermined flux is set to a flux that can cause a voltage drop large enough to generate an arc discharge when X-rays with that flux are incident on the semiconductor crystal 71. Specifically, the processing circuitry 44 uses a positioning image generated in the scan plan. The positioning image is an X-ray image generated based on projection data collected by positioning imaging. Positioning imaging is an imaging method in which the subject P is X-rayed while the X-ray tube 11 is fixed at a fixed angle, such as 0 degrees, 90 degrees, 180 degrees, or 270 degrees. The processing circuitry 44 predicts the time at which X-rays with a predetermined flux will be incident on each detector pixel 70 based on the area occupied by the subject region in the positioning image. The time at which X-rays with a predetermined flux will be incident on each detector pixel 70 may be predicted based on two or more positioning images with different angles. The time may be specified by the elapsed time from the start of imaging, by the number of views from the start of imaging, or by absolute time. Hereinafter, the predicted time will be referred to as the predicted high-flux incidence time.

[0071] It is not necessary to strictly predict the predicted high-flux incidence time for every detector pixel 70 included in each detector module 51. It is sufficient to predict the predicted high-flux incidence time for each of the same partial electrodes 721, 722. When the predicted high-flux incidence times are different for multiple detector pixels 70 belonging to the same partial electrodes 721, 722, the earliest of these times may be set as the predicted high-flux incidence time for the partial electrodes 721, 722.

[0072] 14 is a diagram showing an example of the configuration of a power control system for a high-voltage electrode according to Example 2 of the second embodiment. As shown in Fig. 14, a module control circuit 64 executes a feedback control function 641, a voltage drop control function 643, and a predicted time detection function 644.

[0073] In the predicted time detection function 644, the module control circuit 64 detects the incidence of X-rays at a predetermined flux on either the first partial electrode 721 or the second partial electrode 722. The module control circuit 64 according to the second embodiment detects that the predicted high flux injection time predicted by the prediction function 445 has arrived. In the voltage drop control function 643, when the module control circuit 64 detects that the predicted high flux injection time has arrived, the module control circuit 64 drops the high voltage applied to the other partial electrode 721 or the second partial electrode 722.

[0074] Fig. 15 is a diagram illustrating an example of high voltage control according to Example 2. As shown in Fig. 15, it is assumed that time T4 is set as the predicted time of large flux incidence for the detector pixel 70 corresponding to the first partial electrode 721. It is assumed that the predicted time of large flux incidence for the detector pixel 70 corresponding to the second partial electrode 722 is later than time T4 or does not exist.

[0075] At time T4, the module control circuit 64 detects that the predicted time for large flux incidence has arrived using the predicted time detection function 644. In this case, the voltage applied to the first partial electrode 721 starts to drop.

[0076] At time T5 after time T4, the module control circuit 64 controls the high-voltage application circuit 752 using the voltage drop control function 643 to drop the voltage applied to the second partial electrode 722. In FIG. 15 , the start time T5 of the voltage drop control is delayed from the detection time T4 of the arrival of the predicted high-flux incidence time, but the start time T5 may also coincide with the detection time T4. During the voltage drop control, the module control circuit 64 feedback-controls the high-voltage application circuit 752 so that the voltage applied to the second partial electrode 722 drops with the same time change as the drop in the voltage applied to the first partial electrode 721.

[0077] As described above, according to the second embodiment, the arrival of the predicted high-flux incidence time is regarded as an incidence of high-flux X-rays on the first partial electrode 721. When the arrival of the predicted high-flux incidence time is detected, the module control circuit 64 reduces the voltage applied to the second partial electrode 722. As a result, even if a voltage drop actually occurs on the first partial electrode 721 due to the incidence of high-flux X-rays, the voltage drop on the second partial electrode 722 is also artificially applied, so that the voltage difference between the first partial electrode 721 and the second partial electrode 722 is unlikely to widen to the extent that an arc discharge occurs. Furthermore, by also causing the voltage drop on the second partial electrode 722 to change over time in the same manner as the voltage drop on the first partial electrode 721, it is possible to further narrow the voltage difference between the first partial electrode 721 and the second partial electrode 722. This makes it possible to suppress the occurrence of an arc discharge.

[0078] Example 3 The processing circuitry 44 according to the third embodiment executes a prediction function 445 in addition to an imaging control function 441, a reconstruction function 442, an image processing function 443, and a display control function 444. In the prediction function 445, the processing circuitry 44 predicts the time at which X-rays of a predetermined flux are predicted to be incident (predicted high-flux incident time) based on a scan plan, as in the second embodiment. Next, the processing circuitry 44 specifies a time that is a predetermined time before the predicted high-flux incident time. The predetermined time corresponds to the time required to supply electric charge from a storage element (described later) to the partial electrodes 721 and 722. Hereinafter, the specified time will be referred to as a charge storage start time.

[0079] FIG. 16 is a diagram illustrating a configuration example of a power control system for a high-voltage electrode according to Example 3 of the second embodiment. As illustrated in FIG. 16, a storage element 771 is provided between a first partial electrode 721 and a high-voltage application circuit 751. The storage element 771 is a circuit element that receives power from the high-voltage application circuit 751 and stores charge. The charge stored in the storage element 771 is supplied to the first partial electrode 721 when there is a shortage of charge in the semiconductor crystal region with which the first partial electrode 721 is in contact. Similarly, a storage element 772 is provided between a second partial electrode 722 and a high-voltage application circuit 752. The storage element 772 is a circuit element that receives power from the high-voltage application circuit 752 and stores charge. The charge stored in the storage element 772 is supplied to the second partial electrode 722 when there is a shortage of charge in the semiconductor crystal region with which the second partial electrode 722 is in contact. As the power storage elements 771 and 772, for example, capacitors are suitable.

[0080] The module control circuit 64 executes a power storage start time detection function 645 and a power storage control function 646 in addition to a feedback control function 641. In the power storage start time detection function 645, the module control circuit 64 detects incidence of X-rays at a predetermined flux on either the first partial electrode 721 or the second partial electrode 722. The module control circuit 64 according to the third embodiment detects that the power storage start time specified by the prediction function 445 has been reached. In the power storage control function 646, when it is detected that the high flux incidence predicted time has been reached, the module control circuit 64 controls the high voltage application circuit 751 or the high voltage application circuit 752 to accumulate charge in the power storage element 771 or the power storage element 772 connected to the other partial electrode 721 or the second partial electrode 722.

[0081] 17 is a diagram showing an example of high voltage control according to Example 3 of the second embodiment. As shown in Fig. 17, time T7 is set as the predicted time of large flux incidence for the detector pixel 70 corresponding to the first partial electrode 721, and time T6, which is before time T7, is set as the start time of charge storage in the storage element 771. Note that the start time of charge storage for the detector pixel 70 corresponding to the second partial electrode 722 is set after time T6 or does not exist.

[0082] At time T6, the module control circuit 64 detects the arrival of the charge storage start time using the charge storage start time detection function 645. Upon detecting the arrival of the charge storage start time, the module control circuit 64 controls the high-voltage application circuit 752 using the charge storage control function 646 to start accumulating charge in the charge storage element 771. At time T7, a large flux of X-rays is incident on the first partial electrode 721. As a result of the large flux of X-rays being incident, a large amount of charge is generated in the semiconductor crystal 71, but charge is supplied from the charge storage element 771 to compensate for the insufficient current supply to the semiconductor crystal 71 by the high-voltage electrode 72. This makes it possible to suppress a voltage drop in the first partial electrode 721. This makes it possible to suppress a voltage difference large enough to cause an arc discharge between the first partial electrode 721 and the second partial electrode 722.

[0083] (Third embodiment) The X-ray computed tomography apparatus according to the third embodiment suppresses the occurrence of arc discharge caused by a voltage difference between the detector modules 51 due to the incidence of a large flux of X-rays.

[0084] Fig. 18 is a diagram showing an example of an arrangement of detector modules 51 according to the third embodiment. As shown in Fig. 18, a plurality of detector modules 51 are arranged side by side in the channel direction. Spacers 58 are provided between adjacent detector modules 51. The spacers 58 may be made of an insulating material or a non-insulating material.

[0085] Fig. 19 is a diagram showing an example of the configuration of a power control system for the detector modules 51. Although Fig. 19 shows three detector modules 51, namely, a first detector module 511, a second detector module 512, and a third detector module 513, four or more detector modules 51 may be provided. In the following description, when there is no need to distinguish between the first detector module 511, the second detector module 512, and the third detector module 513, they will be referred to as detector modules 51.

[0086] 19, each detector module 51 has the power control system described in some of the above embodiments. A detector control circuit 59 is connected to each detector module 51.

[0087] The detector control circuit 59 is a control circuit that controls the high voltage of each detector module 51. The detector control circuit 59 detects the incidence of X-rays at a predetermined flux on a certain detector module among the multiple detector modules 51. When the incidence of X-rays at a predetermined flux is detected, the detector control circuit 59 controls the high voltage applied to other detector modules 51 that are adjacent to the certain detector module.

[0088] 20 is a diagram schematically illustrating an example of high-voltage control according to the third embodiment. As shown in FIG. 20, assume that high-flux X-rays are incident on the second detector module 512. In this case, the second detector module 512 performs voltage drop control as in the above-described several examples, and a voltage drop occurs on both the first partial electrode 721 and the second partial electrode 722. At this time, the second detector module 512 transmits an electrical signal (hereinafter, referred to as an incident signal) indicating that high-flux X-rays have been incident to the detector control circuit 59. The incident signal is generated when a voltage drop occurs on the high-voltage electrode 72, when an arc discharge occurs, when the detection current rises above a threshold, when the detection voltage falls below a threshold, when the high-flux incident time has been reached, or the like.

[0089] When receiving an incident signal from the second detector module 512, the detector control circuit 59 supplies an electrical signal (hereinafter referred to as an instruction signal) instructing a voltage drop to the detector module 51 adjacent to the detector module 51 that sent the incident signal. For example, when receiving an incident signal from the second detector module 512, the detector control circuit 59 supplies an instruction signal to the first detector module 511 and the third detector module 513. The detector module 51 to which the instruction signal is supplied controls the high-voltage application circuits 751 and 752 to drop the voltage of the first partial electrodes 721 and 722.

[0090] According to the above-described high voltage control, when a voltage drop occurs due to a high flux of X-rays incident on the second detector module 512, an artificial voltage drop is also created in the first detector module 511 and the third detector module 513 adjacent to the second detector module 512. This makes it possible to suppress the occurrence of arc discharge due to a voltage difference between the detector modules 51.

[0091] (others) The configurations described in the above embodiments are merely examples, and for example, the module control circuit 64 and the detector control circuit 59 may be provided in any of the components included in the X-ray computed tomography apparatus. For example, in the above embodiments, the module control circuit 64 is provided in the detector module 51. However, the module control circuit 64 may be provided on a control board or the like of the X-ray detection apparatus 50, or may be provided in the control device 15 of the gantry 10, or may be provided in the processing circuit 44 or the like of the console 40. Similarly, in the above embodiments, the detector control circuit 59 is provided in the X-ray detection apparatus 50, but it may be provided in the module control circuit 64 or the like of the detector module 51, or may be provided in the control device 15 of the gantry 10, or may be provided in the processing circuit 44 or the like of the console 40.

[0092] In the above embodiment, the high-voltage electrode 72 is divided into two types of partial electrodes: the first partial electrode 721 and the second partial electrode 722. However, this embodiment is not limited to this. For example, the high-voltage electrode 72 may be divided into three or more types of partial electrodes to which a high voltage can be applied independently of each other.

[0093] In the above-described embodiment, the radiation detector is an X-ray detector that detects X-rays. However, the detection target of the radiation detector according to this embodiment is not limited to X-rays, and may be any electromagnetic radiation or particle radiation such as gamma rays, electron beams, proton beams, and neutron beams, and the radiation detector according to this embodiment can be applied to detectors that detect these types of radiation.

[0094] According to at least one of the embodiments described above, the occurrence of arc discharge can be suppressed.

[0095] The term "processor" used in the above description refers to a circuit such as a CPU, a GPU, an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)). A processor realizes its function by reading and executing a program stored in a memory circuit. Note that instead of storing a program in a memory circuit, the processor may be configured so that the program is directly embedded in the circuit. In this case, the processor realizes its function by reading and executing the program embedded in the circuit. Furthermore, instead of executing a program, a function corresponding to the program may be realized by a combination of logic circuits. Note that each processor in this embodiment is not limited to being configured as a single circuit for each processor, but may also be configured as a single processor by combining multiple independent circuits to realize its function. Furthermore, a plurality of components in FIGS. 1, 6, 10, 13, 14, 16, and 19 may be integrated into one processor to realize the functions thereof.

[0096] Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims.

[0097] With respect to the above embodiment, the following supplementary notes are disclosed as one aspect and optional features of the invention.

[0098] (Appendix 1) a direct conversion semiconductor crystal; a first electrode provided on the radiation incident surface side of the semiconductor crystal; a plurality of second electrodes provided opposite the first electrodes with the semiconductor crystal interposed therebetween; the first electrode has a first partial electrode and a second partial electrode to which a high voltage is applied independently and which are divided at least in a channel direction; Detector module.

[0099] (Appendix 2) The first electrode may not be divided into the first partial electrode and the second partial electrode in the column direction perpendicular to the channel direction.

[0100] (Appendix 3) The first electrode may be further divided into the first partial electrode and the second partial electrode in a column direction perpendicular to the channel direction.

[0101] (Appendix 4) The first partial electrodes and the second partial electrodes may be arranged alternately in the channel direction and the column direction.

[0102] (Appendix 5) The device may further include a high voltage application unit that applies a high voltage independently to the first partial electrode and the second partial electrode.

[0103] (Appendix 6) a direct conversion semiconductor crystal; a first electrode provided on the radiation incident surface side of the semiconductor crystal, the first electrode having a first partial electrode and a second partial electrode to which a high voltage is applied independently and which are divided in the channel direction and / or the column direction; a plurality of second electrodes provided opposite to the first electrode with the semiconductor crystal interposed therebetween; a detection unit that detects incidence of a predetermined flux of radiation on the first partial electrode; a control unit that controls a high voltage applied to the second partial electrode when the incidence of the radiation of the predetermined flux is detected; A detector module comprising:

[0104] (Appendix 7) the detection unit detects an increase in current supplied to the first partial electrode to detect the incidence of the radiation of the predetermined flux; When the increase is detected, the control unit may reduce the high voltage applied to the second partial electrode.

[0105] (Appendix 8) the detection unit detects a drop in a high voltage applied to the first partial electrode in order to detect the incidence of the radiation of the predetermined flux; When a drop in the high voltage is detected, the control unit may drop the high voltage applied to the second partial electrode.

[0106] (Appendix 9) the detection unit detects that a time determined based on a scan plan at which the radiation of the predetermined flux is predicted to be incident has arrived, in order to detect the incidence of the radiation of the predetermined flux; When it is detected that the time has been reached, the control unit may reduce the high voltage applied to the second partial electrode.

[0107] (Appendix 10) the detection unit detects that a second time has arrived that is before a first time at which the radiation of the predetermined flux is predicted to be incident, the second time being determined based on a scan plan in order to detect the incidence of the radiation of the predetermined flux; When it is detected that the second time has been reached, the control unit may store electric charge in a power storage element connected to the second partial electrode.

[0108] (Appendix 11) an X-ray tube that generates X-rays; an X-ray detector that detects X-rays generated from the X-ray tube, The X-ray detector comprises: a direct conversion semiconductor crystal; a first electrode provided on the X-ray incident surface side of the semiconductor crystal; a plurality of second electrodes provided opposite the first electrodes with the semiconductor crystal interposed therebetween; the first electrode has a first partial electrode and a second partial electrode to which a high voltage is applied independently and which are divided at least in a channel direction; X-ray computed tomography equipment.

[0109] (Appendix 12) an X-ray tube that generates X-rays; an X-ray detector for detecting X-rays generated from the X-ray tube, the X-ray detector comprising: a direct conversion semiconductor crystal; a first electrode provided on the X-ray incident surface side of the semiconductor crystal, the first electrode having a first partial electrode and a second partial electrode to which a high voltage is applied independently and which are divided in the channel direction and / or the column direction; and a plurality of second electrodes provided opposite the first electrode across the semiconductor crystal; a detection unit that detects incidence of X-rays of a predetermined flux on the first partial electrode; a control unit that controls a high voltage applied to the second partial electrode when the incidence of X-rays of the predetermined flux is detected; An X-ray computed tomography apparatus comprising:

[0110] (Appendix 13) an X-ray tube that generates X-rays; an X-ray detector that detects X-rays generated from the X-ray tube, and has a plurality of detector modules to which a high voltage is applied independently from one another and which are arranged in a channel direction and / or a column direction; a detector that detects incidence of X-rays at a predetermined flux on a first module of the plurality of detector modules; a control unit that controls a high voltage applied to a second module of the plurality of detector modules when incidence of X-rays of the predetermined flux is detected; An X-ray computed tomography apparatus comprising:

[0111] (Appendix 14) a plurality of detector modules that detect X-rays, to which high voltages are applied independently of one another, and that are arranged in a channel direction and / or a column direction; a detector that detects incidence of X-rays at a predetermined flux on a first module of the plurality of detector modules; a control unit that controls a high voltage applied to a second module of the plurality of detector modules when incidence of X-rays of the predetermined flux is detected; An X-ray detection device comprising: [Explanation of symbols]

[0112] 1,2 X-ray computed tomography equipment 10 Mounting stand 11 X-ray tube 12 X-ray detector 13 Rotating Frame 14 X-ray high voltage device 15 Control device 16 Wedge 17 Collimator 18 Data Acquisition System (DAS) 30 Bed 31 Foundation 32 Support frame 33 Top plate 34 Bed drive unit 40 Console 41 memory 42 Display 43 Input Interface 44 Processing circuit 50 X-ray detection device 51 Detector Module 52 Collimator 53 First Fixed Frame 54 Second Fixed Frame 55 First support frame 56 Second support frame 57 Shade 58 Spacer 59 Detector control circuit 61 X-ray detection layer 62 Support stand 63 Control board 64 Module control circuit 65 DAS circuit 70 detector pixels 71 Semiconductor crystals 72 High voltage electrode 73 Pixel electrode 74 Support substrate 441 Shooting control function 442 Reconfiguration function 443 Image Processing Function 444 Display Control Function 445 Predictive Function 511 first detector module 512 Second Detector Module 513 Third Detector Module 641 Feedback Control Function 642 Current change detection function 643 Voltage drop control function 644 Predictive Time Detection Function 645 Power storage start time detection function 646 Power storage control function 721 First partial electrode 722 Second partial electrode 723 terminal 724 terminals 751 High voltage application circuit 752 High voltage application circuit 761 Current / Voltage Detection Element 762 Current / Voltage Detection Element 771 Energy Storage Element 772 Energy storage element

Claims

1. a direct conversion semiconductor crystal; a first electrode provided on the radiation incident surface side of the semiconductor crystal, the first electrode having a first partial electrode and a second partial electrode to which a high voltage is applied independently and which are divided in the channel direction and / or the column direction; a plurality of second electrodes provided opposite the first electrodes with the semiconductor crystal interposed therebetween; a detection unit that detects incidence of radiation of a predetermined flux onto the first partial electrode; a control unit that controls a high voltage applied to the second partial electrode when the incidence of the radiation of the predetermined flux is detected; A detector module comprising:

2. the detection unit detects a drop in the high voltage applied to the first partial electrode to detect the incidence of the radiation of the predetermined flux; the control unit reduces the high voltage applied to the second partial electrode when a drop in the high voltage is detected. The detector module of claim 1 .

3. the detection unit detects an increase in current supplied to the first partial electrode to detect the incidence of the radiation of the predetermined flux; the control unit reduces the high voltage applied to the second partial electrode when the increase is detected. The detector module of claim 1 .

4. the detection unit detects that a time determined based on a scan plan has arrived at which the radiation of the predetermined flux is predicted to be incident, in order to detect the incidence of the radiation of the predetermined flux; When it is detected that the time has been reached, the control unit reduces the high voltage applied to the second partial electrode. The detector module of claim 1 .

5. the detection unit detects that a second time has arrived that is before a first time at which the radiation of the predetermined flux is predicted to be incident, the second time being determined based on a scan plan, in order to detect the incidence of the radiation of the predetermined flux; When the control unit detects that the second time has been reached, the control unit stores electric charge in an electric storage element connected to the second partial electrode. The detector module of claim 1 .

6. an X-ray tube that generates X-rays; an X-ray detector for detecting X-rays generated from the X-ray tube, the X-ray detector comprising: a direct conversion semiconductor crystal; a first electrode provided on an X-ray incident surface side of the semiconductor crystal, the first electrode having a first partial electrode and a second partial electrode to which a high voltage is applied independently and which are divided in a channel direction and / or a column direction; and a plurality of second electrodes provided opposite the first electrode with the semiconductor crystal interposed therebetween; a detection unit that detects incidence of X-rays of a predetermined flux on the first partial electrode; a control unit that controls a high voltage applied to the second partial electrode when the incidence of X-rays of the predetermined flux is detected; An X-ray computed tomography apparatus comprising:

7. an X-ray tube that generates X-rays; an X-ray detector that detects X-rays generated from the X-ray tube, the X-ray detector having a plurality of detector modules to which a high voltage is applied independently of one another and which are arranged in a channel direction and / or a column direction; a detector that detects incidence of X-rays at a predetermined flux on a first module of the plurality of detector modules; a control unit that controls a high voltage applied to a second module of the plurality of detector modules when the incidence of X-rays of the predetermined flux is detected; An X-ray computed tomography apparatus comprising:

8. a plurality of detector modules that detect X-rays, to which high voltages are applied independently from one another, and that are arranged in a channel direction and / or a column direction; a detector that detects incidence of X-rays at a predetermined flux on a first module of the plurality of detector modules; a control unit that controls a high voltage applied to a second module of the plurality of detector modules when the incidence of X-rays of the predetermined flux is detected; An X-ray detection device comprising:

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