Information processing apparatus, information processing method, and information processing program

Abstract

To provide an information processor, an information processing method, and an information processing program for efficiently acquiring calibration data in a PCCT apparatus.SOLUTION: Generating, by an information processing apparatus, first calibration data for correcting a first error included in output data of a radiation detector based on first output data output from the radiation detector by varying a tube current value set in a radiation source in a plurality of stages in a state in which a subject is not present between the radiation source and the radiation detector; In a state in which a phantom is present between the radiation source and the radiation detector, second calibration data for correcting a second error included in output data of the radiation detector is generated on the basis of second output data output from the radiation detector according to tube current values of a smaller number of stages than the plurality of stages.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an information processing device, an information processing method, and an information processing program. [Background technology]

[0002] Patent Document 1 discloses a beam hardening correction method in a CT (Computed Tomography) device equipped with a photon-counting radiation detector (hereinafter referred to as a "PCCT (Photon Counting Computed Tomography) device"). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-113115 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in a PCCT system, calibration data may be acquired by performing a scan with a phantom placed in the system. In this case, since tasks such as phantom placement are required, the calibration data is acquired by an operator such as a maintenance worker operating the PCCT system. Therefore, it is desirable to be able to efficiently acquire calibration data for the PCCT system.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide an information processing device, an information processing method, and an information processing program that can efficiently acquire calibration data in a PCCT device. [Means for solving the problem]

[0006] An information processing device of a first aspect is an information processing device that controls a photon-counting radiation detector and a radiation source and includes at least one processor, wherein the processor generates first calibration data for correcting a first error included in the output data of the radiation detector that is caused by a nonlinear factor attributable to the radiation detector, based on first output data output from the radiation detector by irradiating the radiation detector from the radiation source with tube current values ​​set to the radiation source at multiple levels in a state where no subject is present between the radiation source and the radiation detector; and generates second calibration data for correcting a second error included in the output data of the radiation detector that is caused by a nonlinear factor attributable to radiation passing through the subject, based on second output data output from the radiation detector by irradiating the radiation detector from the radiation source with tube current values ​​that are fewer than the multiple levels in a state where a phantom is present between the radiation source and the radiation detector.

[0007] A second aspect of the information processing device is the information processing device of the first aspect, wherein the processor corrects a first error in third output data output from the radiation detector by irradiating the radiation detector with radiation from the radiation source while a subject is present between the radiation source and the radiation detector, using first calibration data, and corrects a second error in the third output data using second calibration data.

[0008] An information processing device of a third aspect is the information processing device of the first or second aspect, wherein the processor varies the tube current value for each scan in a plurality of scans when generating the first calibration data.

[0009] An information processing device of a fourth aspect is an information processing device of any one of the first to third aspects, wherein the processor varies the tube current value for each scan in multiple scans when generating the second calibration data.

[0010] An information processing device of a fifth aspect is an information processing device of the first or second aspect, in which the processor varies the tube current value in a single scan when generating the first calibration data or the second calibration data, thereby reducing the number of scans when generating the first calibration data or the second calibration data compared to when the tube current value is varied for each scan over multiple scans.

[0011] In an information processing method of a sixth aspect, a processor of an information processing device that controls a photon-counting radiation detector and a radiation source and includes at least one processor performs a process of generating first calibration data for correcting a first error included in the output data of the radiation detector that is caused by a nonlinear factor attributable to the radiation detector, based on first output data output from the radiation detector by irradiating the radiation detector from the radiation source with radiation at tube current values ​​set to the radiation source at multiple levels in a state where no subject is present between the radiation source and the radiation detector; and generating second calibration data for correcting a second error included in the output data of the radiation detector that is caused by a nonlinear factor attributable to radiation passing through the subject, based on second output data output from the radiation detector by irradiating the radiation detector from the radiation source with tube current values ​​that are fewer than the multiple levels in a state where a phantom is present between the radiation source and the radiation detector.

[0012] An information processing program according to a seventh aspect causes a processor of an information processing device, which controls a photon-counting radiation detector and a radiation source and includes at least one processor, to execute the following processes: generate first calibration data for correcting a first error included in the output data of the radiation detector that is caused by a nonlinear factor attributable to the radiation detector, based on first output data output from the radiation detector by irradiating the radiation detector from the radiation source with radiation at tube current values ​​set in the radiation source at multiple levels in a state where no subject is present between the radiation source and the radiation detector; and generate second calibration data for correcting a second error included in the output data of the radiation detector that is caused by a nonlinear factor attributable to radiation passing through the subject, based on second output data output from the radiation detector by irradiating the radiation detector from the radiation source with tube current values ​​that are fewer than the multiple levels in a state where a phantom is present between the radiation source and the radiation detector. [Effects of the Invention]

[0013] According to the present disclosure, calibration data for a PCCT device can be efficiently acquired. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of the configuration of a tomographic imaging system. [Figure 2] FIG. 2 is a block diagram showing an example of a hardware configuration of a console. [Figure 3] FIG. 2 is a block diagram showing an example of a functional configuration of a console. [Figure 4] FIG. 10 is a diagram for explaining a first shooting control. [Figure 5] FIG. 10 is a diagram for explaining a second shooting control. [Figure 6] 10 is a flowchart showing an example of a first calibration data generation process. [Figure 7]10 is a flowchart showing an example of a second calibration data generation process. [Figure 8] 10 is a flowchart illustrating an example of a tomographic image generating process. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, examples of embodiments for carrying out the technology of the present disclosure will be described in detail with reference to the drawings.

[0016] First, the configuration of a tomographic imaging system 10 will be described with reference to Fig. 1. As shown in Fig. 1, the tomographic imaging system 10 according to this embodiment includes a CT device 11 and a console 12.

[0017] The CT device 11 obtains a tomographic image of the subject H by imaging the subject H using X-rays, which are an example of radiation. The CT device 11 includes a gantry 18 and a bed device 19. FIG. 1 is a front view of the gantry 18 and the bed device 19. The bed device 19 includes a tabletop 19A on which the subject H can be placed in a supine position. In the following description, the longitudinal direction of the tabletop 19A is defined as the Z-axis direction, the lateral direction of the tabletop 19A as the X-axis direction, and the vertical direction as the Y-axis direction. The tabletop 19A can move in the Z-axis direction while remaining horizontal. The gantry 18 has an overall annular shape and is formed in the center with a circular opening 18A having a diameter greater than the width of the tabletop 19A. During imaging, the tabletop 19A, on which the subject H is placed, moves in the Z-axis direction relative to the gantry 18 to enter the opening 18A. Imaging is performed while the tabletop 19A is moving relative to the gantry 18.

[0018] A radiation source 21, a radiation detector 22, and a frame 23 are arranged inside the gantry 18. The radiation source 21 irradiates radiation toward the subject H. The radiation detector 22 detects the radiation that has passed through the subject H. The radiation that has passed through the subject H is attenuated by interaction with structures such as organs and bones inside the subject H (for example, absorption and scattering of radiation). Each structure has its own unique attenuation coefficient for radiation, and the radiation that has passed through a structure carries information reflecting the physical properties of the structure. The radiation detector 22 detects radiation that reflects the physical properties of the structures inside the subject H. The radiation detector 22 has a detection surface on which detection elements are arranged two-dimensionally, and outputs a detection signal for each detection element. Therefore, the radiation detector 22 can detect radiation at each transmission position where it passes through the structure of the subject H. Furthermore, the radiation detector 22 has a substantially arc-shaped configuration in accordance with the curvature of the gantry 18, and the detection surface is also curved. The radiation detector 22 is an example of a photon-counting type radiation detector, and is a radiation detector that can count the number of incident X-ray photons.

[0019] The radiation source 21 and the radiation detector 22 are disposed in opposing positions within the gantry 18, and rotate around the Z axis while maintaining their opposing orientation. The frame 23 is annular and rotatably supports the radiation source 21 and the radiation detector 22. During imaging, the gantry 18 rotates the radiation source 21 and the radiation detector 22 around the subject H on the tabletop 19A, and acquires detection signals from the radiation detector 22 at multiple positions in the circumferential direction around the Z axis, which corresponds to the body axis of the subject H. During imaging, the tabletop 19A also moves in the Z axis direction in synchronization with the rotation of the radiation source 21 and the radiation detector 22.

[0020] The DAS (Data Acquisition System) 25 collects detection signals output by the radiation detector 22, generates output data for each position around the Z axis based on the collected detection signals, and outputs the generated output data to the console 12. When the subject H is present between the radiation source 21 and the radiation detector 22, this output data is projection data of the subject H. Hereinafter, the output data output by the DAS 25 to the console 12 will be referred to as output data of the radiation detector 22.

[0021] An irradiation field limiter 24 (also called a collimator) that limits the radiation irradiation field is disposed in front of the radiation source 21 in the irradiation direction. The irradiation field limiter 24 has an irradiation aperture whose outline is defined by a plurality of shielding plates that block radiation, and the size of the irradiation aperture can be changed by moving the shielding plates. A voltage is supplied to the radiation source 21 from a high-voltage generator 26. The radiation source 21 and the radiation detector 22 are electrically connected to the frame 23, for example, by a slip ring system, and power supply and data transmission / reception are performed via the slip ring. The slip ring system connection enables helical scan imaging, in which imaging is performed while the radiation source 21 and the radiation detector 22 are rotated in one direction without reversing the rotation direction.

[0022] The console 12 controls the radiation source 21 and the radiation detector 22 via a control device (not shown) provided in the gantry 18. The console 12 is an example of an information processing device that controls a photon-counting type radiation detector and a radiation source. The imaging conditions of the CT device 11 are set by operation from the console 12. The imaging conditions include the radiation irradiation conditions of the radiation source 21 and the imaging range. The radiation irradiation conditions include the tube voltage (unit: kV), tube current (unit: mA), and radiation irradiation time (unit: msec) applied to the radiation source 21. The imaging range is adjusted, for example, in the XY plane by changing the size of the irradiation opening of the irradiation field limiter 24, and in the Z-axis direction by changing the movement range of the tabletop 19A.

[0023] The hardware configuration of the console 12 according to this embodiment will be described with reference to FIG. 2. Examples of the console 12 include a computer such as a personal computer or a server computer. As shown in FIG. 2, the console 12 includes a CPU (Central Processing Unit) 31, a memory 32 as a temporary storage area, and a non-volatile storage unit 33. The console 12 also includes a display 34 such as a liquid crystal display, an input device 35 such as a keyboard and a mouse, and a network I / F (Interface) 36 connected to the CT device 11. The CPU 31, the memory 32, the storage unit 33, the display 34, the input device 35, and the network I / F 36 are connected to a bus 37. The CPU 31 is an example of a processor according to the disclosed technology.

[0024] The storage unit 33 is realized by a hard disk drive (HDD), a solid state drive (SSD), a flash memory, or the like. The storage unit 33 serving as a storage medium stores an information processing program 40. The CPU 31 reads the information processing program 40 from the storage unit 33, expands it in the memory 32, and executes the expanded information processing program 40.

[0025] In the CT apparatus 11 according to this embodiment, the output data of the radiation detector 22 contains an error (hereinafter referred to as a "first error") due to a nonlinear factor caused by the radiation detector 22. An example of the first error is an error due to pile-up, which is a nonlinear factor.

[0026] The output data from the radiation detector 22 also includes errors caused by factors other than the radiation detector 22. Specifically, the output data from the radiation detector 22 includes errors (hereinafter referred to as "second errors") due to nonlinear factors caused by radiation passing through the subject H. Examples of second errors include errors due to beam hardening, which is a nonlinear factor.

[0027] The console 12 according to this embodiment has the function of generating calibration data for correcting a first error (hereinafter referred to as "first calibration data") and calibration data for correcting a second error (hereinafter referred to as "second calibration data").

[0028] Next, the functional configuration of the console 12 will be described with reference to Fig. 3. As shown in Fig. 3, the console 12 includes an imaging control unit 50, an acquisition unit 52, a generation unit 54, a correction unit 56, and a reconstruction unit 58. The CPU 31 executes the information processing program 40, thereby functioning as the imaging control unit 50, the acquisition unit 52, the generation unit 54, the correction unit 56, and the reconstruction unit 58.

[0029] 4, the imaging control unit 50 performs control (hereinafter referred to as "first imaging control") to perform imaging in a state where the subject H and the bed device 19 are not present between the radiation source 21 and the radiation detector 22. In the first imaging control, the imaging control unit 50 sets a tube current value in the radiation source 21 at a plurality of different levels, and causes the radiation source 21 to irradiate the radiation detector 22 with radiation. This tube current value is set, for example, at the time of shipment or by a maintenance technician when the first imaging control is performed.

[0030] For example, in the first imaging control, the imaging control unit 50 varies the tube current value in multiple stages within a range equal to or greater than the lower limit and equal to or less than the upper limit used in actual imaging. In this embodiment, in the first imaging control, the imaging control unit 50 performs one scan at a single tube current value and varies the tube current value for each of the multiple scans. The DAS 25 collects detection signals output by the radiation detector 22 for each scan and outputs output data generated based on the collected detection signals to the console 12. That is, in the first imaging control, output data of the radiation detector 22 corresponding to each of the multiple tube current values ​​is obtained. Hereinafter, the output data output from the radiation detector 22 in the first imaging control is referred to as "first output data." The first output data is used by the generator 54 to generate first calibration data, which will be described later. That is, when generating the first calibration data, the imaging control unit 50 varies the tube current value for each of the multiple scans. In this embodiment, one scan means capturing an image while rotating the radiation source 21 and the radiation detector 22 360° around the Z axis.

[0031] 5, the imaging control unit 50 performs control (hereinafter referred to as "second imaging control") to perform imaging with a phantom P present between the radiation source 21 and the radiation detector 22. The phantom P is a simulation of the subject H, and its size (including thickness, length, and width), shape, material, etc. are known. In the second imaging control, the phantom P is placed using a jig or the like (not shown).

[0032] In the second imaging control, the imaging control unit 50 causes the radiation source 21 to irradiate the radiation detector 22 with radiation in accordance with a tube current value having a number of stages that is fewer than the number of stages of the tube current value in the first imaging control. In this embodiment, an example will be described in which the number of stages of the tube current value in the second imaging control is two or more, but the number of stages of the tube current value in the second imaging control may also be one.

[0033] For example, in the second imaging control, the imaging control unit 50 uses some of the multiple tube current values ​​used in the first imaging control as the tube current values, thereby setting a smaller number of tube current values ​​than the number of tube current values ​​in the first imaging control for the radiation source 21. In the present embodiment, in the second imaging control, the imaging control unit 50 performs one scan with one tube current value, and in multiple scans, the imaging control unit 50 sets different tube current values ​​for each scan.

[0034] The DAS 25 collects detection signals output by the radiation detector 22 for each scan, and outputs output data generated based on the collected detection signals to the console 12. That is, in the second imaging control, output data from the radiation detector 22 corresponding to each of multiple stages of tube current values ​​is obtained. Hereinafter, the output data output from the radiation detector 22 under the second imaging control will be referred to as "second output data." The second output data is used to generate second calibration data by the generation unit 54, which will be described later. That is, when generating the second calibration data, the imaging control unit 50 varies the tube current value for each scan over multiple scans.

[0035] As an example, as shown in FIG. 1, the imaging control unit 50 performs control to perform imaging in a state where the subject H is present between the radiation source 21 and the radiation detector 22 (hereinafter referred to as "third imaging control"). In the third imaging control, the imaging control unit 50 sets a tube current value in the radiation source 21 in accordance with the imaging conditions. The imaging conditions are set by a technician or the like in accordance with the subject H to be examined, the part of the body to be examined, and the purpose of the examination. Hereinafter, the output data output from the radiation detector 22 in accordance with the third imaging control will be referred to as "third output data."

[0036] The acquisition unit 52 acquires first output data obtained by the first imaging control from the DAS 25. Moreover, the acquisition unit 52 acquires second output data obtained by the second imaging control from the DAS 25. Moreover, the acquisition unit 52 acquires third output data obtained by the third imaging control from the DAS 25. Moreover, the acquisition unit 52 acquires from the storage unit 33, among the first calibration data and second calibration data stored in the storage unit 33 by the generation unit 54 described later, the first calibration data and second calibration data corresponding to tube current values ​​included in the imaging conditions in the third imaging control.

[0037] The generation unit 54 generates first calibration data for correcting a first error included in the output data of the radiation detector 22, based on the first output data acquired by the acquisition unit 52. As described above, the first output data is acquired when the subject H is not present between the radiation source 21 and the radiation detector 22. Therefore, if the first output data does not include the first error, the projection value based on the first output data is considered to be zero. Therefore, the generation unit 54 generates first calibration data for each detection element of the radiation detector 22 so that, when subtracted from the first output data, the projection value based on the first output data becomes zero. The generation unit 54 generates first calibration data for each tube current value and stores the first calibration data in the storage unit 33 in association with the tube current value. Note that the generation unit 54 may store the first calibration data in the storage unit 33 in the form of a function that, when a tube current value is input, outputs first calibration data corresponding to the input tube current value.

[0038] Furthermore, the generation unit 54 generates second calibration data for correcting a second error included in the output data of the radiation detector 22, based on the second output data acquired by the acquisition unit 52. As described above, the phantom P used when acquiring the second output data is a simulation of the subject H, and its size (including thickness, length, and width), shape, material, and the like are known. The incident angle of radiation with respect to the phantom P when acquiring the second output data, as well as the radiation dose, are also known. Therefore, the theoretical value of the second output data when the second output data does not include the second error can be calculated in advance. Therefore, the generation unit 54 derives, as second calibration data, a correction coefficient for each detecting element of the radiation detector 22 such that the actual measured value of the second output data matches the theoretical value of the second output data. The generation unit 54 generates second calibration data for each tube current value, and stores the second calibration data in the storage unit 33 in association with the tube current value. The generating unit 54 may store the second calibration data in the storage unit 33 in the form of a function that, when a tube current value is input, outputs second calibration data corresponding to the input tube current value.

[0039] The correction unit 56 corrects a first error in the third output data acquired by the acquisition unit 52 using the first calibration data, and corrects a second error in the third output data using the second calibration data. Specifically, the correction unit 56 first corrects the first error in the third output data by subtracting the first calibration data from the third output data for each corresponding detection element. Next, the correction unit 56 corrects the second error by multiplying the third output data after the first error correction by the second calibration data for each corresponding detection element.

[0040] The reconstruction unit 58 generates a tomographic image by reconstructing the tomographic image based on the third output data corrected by the correction unit 56. The reconstruction of the tomographic image based on the third output data is performed by, for example, a filtered back projection method.

[0041] Next, the operation of the console 12 will be described with reference to Figs. 6 to 8. The CPU 31 executes the information processing program 40, thereby executing a first calibration data generation process shown in Fig. 6, a second calibration data generation process shown in Fig. 7, and a tomographic image generation process shown in Fig. 8. The first calibration data generation process is executed periodically, such as once a day, and when a maintenance person inputs an instruction to start execution. The second calibration data generation process is executed when a maintenance person inputs an instruction to start execution. The tomographic image generation process is executed when a technician inputs an instruction to start execution.

[0042] 6, as described above, the imaging control unit 50 performs the first imaging control to perform imaging in a state where the subject H is not present between the radiation source 21 and the radiation detector 22. In step S12, the acquisition unit 52 acquires, from the DAS 25, the first output data obtained by the first imaging control performed in step S10.

[0043] In step S14, the generation unit 54 generates first calibration data for correcting the first error included in the output data of the radiation detector 22, based on the first output data acquired in step S12, as described above. Then, the generation unit 54 associates the tube current value with the first calibration data and stores the data in the storage unit 33. When the processing of step S14 ends, the first calibration data generation processing ends.

[0044] 7, the imaging control unit 50 performs the second imaging control to perform imaging in a state where the phantom P is present between the radiation source 21 and the radiation detector 22, as described above. In step S22, the acquisition unit 52 acquires, from the DAS 25, second output data obtained by the second imaging control performed in step S20.

[0045] In step S24, the generation unit 54 generates second calibration data for correcting the second error included in the output data of the radiation detector 22, based on the second output data acquired in step S22, as described above. Then, the generation unit 54 associates the tube current value with the second calibration data and stores the data in the storage unit 33. When the processing of step S24 ends, the second calibration data generation processing ends.

[0046] 8, the imaging control unit 50 performs the third imaging control, as described above, to perform imaging with the subject H present between the radiation source 21 and the radiation detector 22. In step S32, the acquisition unit 52 acquires third output data obtained by the third imaging control performed in step S30 from the DAS 25. In step S34, the acquisition unit 52 acquires, from the storage unit 33, first calibration data and second calibration data corresponding to the tube current value included in the imaging conditions for the third imaging control.

[0047] In step S36, the correction unit 56 corrects the first error of the third output data acquired in step S32 using the first calibration data acquired in step S34, and corrects the second error of the third output data using the second calibration data acquired in step S34, as described above. In step S38, the reconstruction unit 58 generates a tomographic image by reconstructing the tomographic image based on the third output data corrected in step S36. When the processing of step S38 ends, the tomographic image generation processing ends.

[0048] As described above, according to this embodiment, in the second imaging control in which the phantom P is positioned by a maintenance worker or the like, the number of stages of the tube current value is set to a number that is smaller than that in the first imaging control. This reduces the time required for the second imaging control compared to when the number of stages of the tube current value in the second imaging control is the same as that in the first imaging control. Therefore, calibration data for the PCCT apparatus can be acquired efficiently.

[0049] In the above embodiment, the imaging control unit 50 performs one scan with a single tube current value and varies the tube current value for each of the multiple scans when generating the first calibration data. However, the disclosed technology is not limited to this configuration. By varying the tube current value in multiple steps in a single scan when generating the first calibration data, the imaging control unit 50 may reduce the number of scans required to generate the first calibration data compared to when varying the tube current value for each of the multiple scans. For example, the imaging control unit 50 may vary the tube current value each time the radiation source 21 and the radiation detector 22 are rotated a predetermined amount around the Z axis in a single scan when generating the first calibration data. This reduces the time required for generating the first calibration data. Similarly, the imaging control unit 50 may vary the tube current value in multiple steps in a single scan when generating the second calibration data compared to when varying the tube current value for each of the multiple scans.

[0050] Furthermore, at least one of the functional units included in the console 12 in the above embodiment may be included in another device such as a control device included in the gantry 18.

[0051] Furthermore, in the above embodiment, the following various processors can be used as the hardware structure of a processing unit that executes various processes, such as each functional section of the console 12. As described above, the various processors include a CPU, which is a general-purpose processor that executes software (programs) and functions as various processing sections, as well as dedicated electrical circuits, such as a programmable logic device (PLD), a processor whose circuit configuration can be changed after manufacture, such as an FPGA, and an application specific integrated circuit (ASIC), which is a processor with a circuit configuration designed specifically for executing specific processes.

[0052] A single processing unit may be configured with one of these various processors, or may be configured with a combination of two or more processors of the same or different types (for example, a combination of multiple FPGAs, or a combination of a CPU and an FPGA). Also, multiple processing units may be configured with a single processor.

[0053] Examples of configuring multiple processing units with a single processor include, first, a form in which one processor is configured with a combination of one or more CPUs and software, and this processor functions as multiple processing units, as typified by computers such as client and server. Second, a form in which a processor is used to realize the functions of the entire system including multiple processing units with a single IC (Integrated Circuit) chip, as typified by systems on chips (SoCs). In this way, various processing units are configured using one or more of the above-mentioned various processors as a hardware structure.

[0054] Furthermore, more specifically, the hardware structure of these various processors can be an electric circuit that combines circuit elements such as semiconductor elements.

[0055] In the above embodiment, the information processing program 40 is pre-stored (installed) in the storage unit 33, but the present invention is not limited to this. The information processing program 40 may be provided in a form recorded on a recording medium such as a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), or a USB (Universal Serial Bus) memory. The information processing program 40 may also be downloaded from an external device via a network. [Explanation of symbols]

[0056] 10 Tomography system 11 CT device 12 Console 18 Gantry 18A opening 19 Bed Device 19A Top plate 21 Radiation source 22 Radiation detector 23 frames 24 Irradiation field limiter 25 DAS 26 High Voltage Generator 31 CPU 32 memory 33 Storage section 34 Display 35 Input Devices 36 Network I / F 37 Bus 40 Information Processing Program 50 Shooting control unit 52 Acquisition Department 54 Generation part 56 Correction unit 58 Reconstruction part H Subject P Phantom

Claims

1. An information processing device that controls a photon-counting radiation detector and a radiation source and includes at least one processor, The processor: generating first calibration data for correcting a first error included in the output data of the radiation detector according to a nonlinear factor caused by the radiation detector, based on first output data output from the radiation detector by irradiating the radiation detector from the radiation source with a tube current value set in the radiation source at a plurality of different levels in a state where no subject is present between the radiation source and the radiation detector; In a state where a phantom is present between the radiation source and the radiation detector, radiation is irradiated from the radiation source to the radiation detector in accordance with tube current values ​​having a number of stages less than the plurality of stages, and based on second output data output from the radiation detector, second calibration data is generated to correct a second error included in the output data of the radiation detector that is caused by a nonlinear factor resulting from the radiation passing through a subject. Information processing device.

2. The processor: a first error in third output data output from the radiation detector by irradiating the radiation detector with radiation from the radiation source while a subject is present between the radiation source and the radiation detector, the first error in the third output data being output from the radiation detector being corrected using the first calibration data, and the second error in the third output data being corrected using the second calibration data; The information processing device according to claim 1 .

3. The processor: When generating the first calibration data, the tube current value is varied for each scan in a plurality of scans.

3. The information processing device according to claim 1.

4. The processor: When generating the second calibration data, the tube current value is varied for each scan in a plurality of scans.

3. The information processing device according to claim 1.

5. The processor: By varying the tube current value in one scan when generating the first calibration data or the second calibration data, the number of scans when generating the first calibration data or the second calibration data is reduced compared to a case where the tube current value is varied for each scan in a plurality of scans.

3. The information processing device according to claim 1.

6. An information processing device that controls a photon-counting radiation detector and a radiation source and includes at least one processor, generating first calibration data for correcting a first error included in the output data of the radiation detector according to a nonlinear factor caused by the radiation detector, based on first output data output from the radiation detector by irradiating the radiation detector from the radiation source with a tube current value set in the radiation source at a plurality of different levels in a state where no subject is present between the radiation source and the radiation detector; In a state where a phantom is present between the radiation source and the radiation detector, radiation is irradiated from the radiation source to the radiation detector in accordance with tube current values ​​having a number of stages less than the plurality of stages, and based on second output data output from the radiation detector, second calibration data is generated to correct a second error included in the output data of the radiation detector that is caused by a nonlinear factor resulting from the radiation passing through a subject. An information processing method that performs processing.

7. An information processing device that controls a photon-counting radiation detector and a radiation source and includes at least one processor, generating first calibration data for correcting a first error included in the output data of the radiation detector according to a nonlinear factor caused by the radiation detector, based on first output data output from the radiation detector by irradiating the radiation detector from the radiation source with a tube current value set in the radiation source at a plurality of different levels in a state where no subject is present between the radiation source and the radiation detector; In a state where a phantom is present between the radiation source and the radiation detector, radiation is irradiated from the radiation source to the radiation detector in accordance with tube current values ​​having a number of stages less than the plurality of stages, and based on second output data output from the radiation detector, second calibration data is generated to correct a second error included in the output data of the radiation detector that is caused by a nonlinear factor resulting from the radiation passing through a subject. An information processing program for executing processing.

Images