X-ray computer tomography apparatus and control method

Abstract

To prevent defect of a reconstruction image caused by a change of power consumption of a readout circuit and degradation of quantitativity.SOLUTION: An X-ray computer tomography apparatus includes an X-ray detection element, a readout circuit, and a determination part. The X-ray computer tomography apparatus detects X-rays. The readout circuit reads out an output signal of the X-ray detection element. The determination part determines whether or not an index about power consumption of the readout circuit in the main scan on the basis of at least either information of a scan plan set for the main scan or information obtained by positioning imaging before the main scan is executed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] BACKGROUND ART Conventionally, an X-ray detector such as a photon-counting detector provided in an X-ray computed tomography (CT) apparatus includes an X-ray detection element that detects X-rays and a readout circuit that reads out an output signal from the X-ray detection element.

[0003] Generally, in such an X-ray detector configuration, when the dose of X-rays incident on the X-ray detection element increases, the power consumption of the readout circuit changes, which can result in poor reconstructed images or a deterioration in quantitative accuracy. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2016 / 039054 [Patent Document 2] International Publication No. 2002 / 042797 [Patent Document 3] Japanese Patent Application Publication No. 2020-88520 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 prevent defects in reconstructed images and deterioration of quantitativeness due to changes in power consumption of the readout circuit. 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] An X-ray CT apparatus according to an embodiment includes an X-ray detection element, a readout circuit, and a determination unit. The X-ray detection element detects X-rays. The readout circuit reads out an output signal from the X-ray detection element. Before a main scan is performed, the determination unit determines whether an index related to power consumption of the readout circuit during the main scan exceeds a reference value based on at least one of information on a scan plan set for the main scan and information obtained by positioning imaging. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of an X-ray CT apparatus according to the first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing an example of the configuration of the X-ray detector according to the first embodiment. [Figure 3] FIG. 3 is a schematic diagram showing the circuit operation when a high dose of X-rays is incident on the X-ray detector according to the first embodiment. [Figure 4] FIG. 4 is a flowchart showing the processing procedure of the processing performed by the X-ray CT apparatus according to the first embodiment. [Figure 5] FIG. 5 is a flowchart showing the processing procedure of the processing performed by the X-ray CT apparatus according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of an X-ray CT apparatus will be described in detail with reference to the drawings.

[0009] (First embodiment) FIG. 1 is a diagram showing an example of the configuration of an X-ray CT apparatus according to the first embodiment.

[0010] 1, the X-ray CT apparatus 1 according to this embodiment includes a gantry device 10, a bed device 30, and a console device 40. In this embodiment, the rotation axis of the rotating frame 13 in a non-tilted state or the longitudinal direction of the tabletop 33 of the bed device 30 is defined as the Z-axis direction, the axis perpendicular to the Z-axis direction and horizontal to the floor surface is defined as the X-axis direction, and the axis perpendicular to the Z-axis direction and perpendicular to the floor surface is defined as the Y-axis direction.

[0011] The gantry device 10 is a device that irradiates X-rays onto an object P, such as a patient, detects the X-rays that have passed through the object P, and outputs the detected X-rays to a console device 40. Specifically, the gantry device 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 DAS (Data Acquisition System) 18. Note that, for convenience of illustration, FIG. 1 shows the gantry device 10 as viewed from the X-axis direction and the Z-axis direction, but in reality, the X-ray CT device 1 has one gantry device 10.

[0012] The X-ray tube 11 is a vacuum tube having a cathode (filament) that generates thermoelectrons and an anode (target) that generates X-rays upon impact of the thermoelectrons. The X-ray tube 11 generates X-rays to be irradiated onto the subject P by irradiating thermoelectrons from the cathode to the anode when a high voltage is applied from the X-ray high voltage device 14. For example, the X-ray tube 11 is a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermoelectrons.

[0013] The wedge 16 is a filter for adjusting the amount of X-rays irradiated from the X-ray tube 11. Specifically, the wedge 16 is a filter that transmits and attenuates the X-rays irradiated from the X-ray tube 11 so that the X-rays irradiated from the X-ray tube 11 to the subject P have a predetermined distribution. For example, the wedge 16 is a filter made by processing aluminum so as to have a predetermined target angle and a predetermined thickness. The wedge 16 is also called a wedge filter or a bow-tie filter.

[0014] The X-ray aperture 17 includes a lead plate or the like for narrowing down the irradiation range of the X-rays transmitted through the wedge 16, and a slit is formed by combining a plurality of lead plates or the like. The X-ray aperture 17 may also be called a collimator.

[0015] The X-ray detector 12 detects X-rays emitted from the X-ray tube 11 and passing through the subject P, and outputs an electrical signal corresponding to the dose of the X-rays to the DAS 18. For example, the X-ray detector 12 has a plurality of X-ray detection element rows, in which a plurality of X-ray detection elements are arranged in the channel direction along an arc centered on the focal point of the X-ray tube 11. For example, the X-ray detector 12 has a structure in which a plurality of X-ray detection element rows, in which a plurality of X-ray detection elements are arranged in the channel direction, are arranged in the row direction (also called the slice direction or row direction).

[0016] The DAS 18 has an amplifier that amplifies the electrical signals output from each X-ray detection element of the X-ray detector 12 and an A / D converter that converts the electrical signals amplified by the amplifier into digital signals, and generates detection data. The DAS 18 then transfers the generated detection data to the console device 40.

[0017] The X-ray high voltage device 14 has electric circuits such as a transformer and a rectifier, and includes a high voltage generator having a function of generating a high voltage to be applied to the X-ray tube 11, and an X-ray control device that controls the output voltage according to the X-ray output irradiated by the X-ray tube 11. For example, the high voltage generator may be of a transformer type or an inverter type.

[0018] Here, the X-ray high voltage device 14 may be provided on the rotating frame 13, which will be described later, or may be provided on the fixed frame (not shown) side of the gantry device 10. The fixed frame is a support frame that rotatably supports the rotating frame 13.

[0019] The rotating frame 13 is an annular frame to which the X-ray tube 11 and the X-ray detector 12 are fixed and which rotates about a rotation axis. Specifically, the rotating frame 13 supports the X-ray tube 11 and the X-ray detector 12 in a state in which they are arranged opposite each other with the rotation axis in between, and rotates the X-ray tube 11 and the X-ray detector 12 using a control device 15, which will be described later. In addition to the X-ray tube 11 and the X-ray detector 12, the rotating frame 13 also supports an X-ray high-voltage device 14.

[0020] Here, the rotating frame 13 is rotatably supported by a non-rotating portion (e.g., a fixed frame, not shown) of the gantry 10. 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, for example, in the non-rotating portion, and the bearing is physically connected to the rotating frame 13 and the motor, and the rotating frame 13 rotates in response to the rotational force of the motor.

[0021] Furthermore, the rotating frame 13 and the non-rotating portion are each provided with a non-contact or contact communication circuit, which allows communication between the unit supported by the rotating frame 13 and the non-rotating portion or an external device of the gantry 10. For example, when 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 non-rotating portion of the gantry 10, and is then transferred from the non-rotating portion to the console device 40 by the transmitter. Note that, as the communication method, other non-contact data transmission methods such as capacitive coupling and radio wave methods, as well as contact data transmission methods using a slip ring and electrode brushes, may also be used.

[0022] The control device 15 includes a processing circuit having a CPU (Central Processing Unit) and the like, and a driving mechanism such as a motor and an actuator. The control device 15 has a function of receiving an input signal from the console device 40 or an input interface 43 attached to the gantry device 10 and controlling the operation of the gantry device 10 and the bed device 30. For example, the control device 15 receives the input signal and controls the rotation of the rotating frame 13, the tilt of the gantry device 10, and the operation of the bed device 30 and the tabletop 33. The control of tilting the gantry device 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 the input interface 43 attached to the gantry device 10. The control device 15 may be provided in the gantry device 10 or the console device 40.

[0023] The bed device 30 is a device on which the subject P, who is the subject of the scan, is placed and moved, and includes a base 31, a bed driving device 32, a top plate 33, and a support frame 34. The base 31 is a housing that supports the support frame 34 so that it can move in the vertical direction. The bed driving device 32 is a motor or actuator that moves the top plate 33, on which the subject P is placed, in the longitudinal direction of the top plate 33. The top plate 33, which is provided on the upper surface of the support frame 34, is a plate on which the subject P is placed. Note that the bed driving device 32 may move the support frame 34 in addition to the top plate 33 in the longitudinal direction of the top plate 33.

[0024] The console device 40 is a device that accepts operations of the X-ray CT apparatus 1 by an operator and reconstructs CT image data using detection data collected by the gantry device 10. The console device 40 has a memory 41, a display 42, an input interface 43, and a processing circuit 44. Note that, although an example in which the console device 40 and the gantry device 10 are separate entities will be described here, the gantry device 10 may include the console device 40 or some of the components of the console device 40.

[0025] The memory 41 is realized by, for example, a semiconductor memory element such as a RAM (Random Access Memory), a flash memory, a hard disk, an optical disk, etc. The memory 41 stores, for example, projection data and CT image data. Here, the memory 41 is an example of a storage unit.

[0026] The display 42 displays various types of information. For example, the display 42 outputs medical images (CT images) generated by the processing circuitry 44, a GUI (Graphical User Interface) for receiving various operations from the operator, and the like. For example, the display 42 is a liquid crystal display or a CRT (Cathode Ray Tube) display. Note that the display 42 may be provided on the gantry device 10, for example. Furthermore, 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 console device 40 main body.

[0027] 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 scan conditions for collecting projection data, reconstruction conditions for reconstructing CT image data, image processing conditions for generating post-processed image data from CT image data, and the like. For example, the input interface 43 is realized by a mouse, keyboard, trackball, switch, button, joystick, or the like. Note that the input interface 43 may be provided in the gantry device 10, for example. Furthermore, the input interface 43 may be configured by a tablet terminal or the like capable of wireless communication with the console device 40 main body, for example.

[0028] The processing circuitry 44 controls the overall operation of the X-ray CT apparatus 1. For example, the processing circuitry 44 has a system control function 441, a preprocessing function 442, a reconstruction processing function 443, an image processing function 444, a determination function 445, and a notification function 446.

[0029] The system control function 441 controls various functions of the control device 15 of the gantry device 10 and the processing circuit 44 based on input operations received from the operator via the input interface 43. For example, the system control function 441 controls the control device 15 of the gantry device 10 based on scan conditions received from the operator, thereby controlling the CT scan executed in the X-ray CT device 1. Furthermore, the system control function 441 controls the generation and display of CT image data in the console device 40 by controlling the pre-processing function 442, the reconstruction processing function 443, and the image processing function 444 based on the reconstruction conditions and image processing conditions received from the operator.

[0030] The pre-processing function 442 generates projection data by performing pre-processing such as logarithmic conversion processing, offset correction processing, inter-channel sensitivity correction processing, beam hardening correction, etc. on the detection data output from the DAS 18. Note that the data before pre-processing (detection data) and the data after pre-processing may be collectively referred to as projection data.

[0031] The reconstruction processing function 443 performs reconstruction processing using a filtered back projection method, an iterative reconstruction method, or the like on the projection data generated by the preprocessing function 442 to generate CT image data (reconstructed image data).

[0032] The image processing function 444 converts the CT image data generated by the reconstruction processing function 443 into tomographic image data of an arbitrary cross section or three-dimensional image data by a known method based on an input operation received from the operator via the input interface 43. Note that the generation of three-dimensional image data may be performed directly by the reconstruction processing function 443.

[0033] The main configuration of the X-ray CT apparatus 1 according to this embodiment has been described above. In this embodiment, an example will be described in which the X-ray detector 12 in the above-described configuration is a photon-counting detector.

[0034] FIG. 2 is a schematic diagram showing an example of the configuration of the X-ray detector 12 according to the first embodiment.

[0035] 2, the X-ray detector 12 includes a semiconductor detection element 121, a readout IC (Integrated Circuit) 122, a power supply transmission circuit 123, and a power supply 124. Here, the semiconductor detection element 121 is an example of an X-ray detection element, and the readout IC 122 is an example of a readout circuit.

[0036] The semiconductor detection element 121 converts incident X-rays into electric charges. Specifically, the semiconductor detection element 121 is composed of a plurality of electrodes, and each time an X-ray photon is incident, a bias voltage is applied from a high-voltage power supply (not shown) to read out an electric pulse signal having a pulse height proportional to the amount of electric charge corresponding to the dose of the incident X-ray, and output it to the IC 122. For example, the semiconductor detection element 121 may be made of CZT (cadmium zinc telluride: CdZnTe), CdTe (cadmium telluride), Ge (germanium), Si (silicon), or the like.

[0037] The readout IC 122 is connected to the semiconductor detection element 121 and reads and processes the electrical pulse signal output from the semiconductor detection element 121. Specifically, each time an electrical pulse signal is output from the semiconductor detection element 121, the readout IC 122 uses power supplied from a power source 124 to compare the output electrical pulse signal with multiple thresholds for pulse height discrimination, thereby counting the number of X-ray photons incident on the semiconductor detection element 121. The readout IC 122 also measures the energy of the counted X-ray photons by performing arithmetic processing based on the magnitude of each charge. The readout IC 122 also performs analog-to-digital (A / D) conversion on the signal from the semiconductor detection element 121, thereby outputting the count result of the number of X-ray photons to the DAS 18 as digital data. For example, the readout IC 122 is implemented by an application specific integrated circuit (ASIC).

[0038] The power supply transmission circuit 123 transmits the power supplied from the power supply 124 to the read IC 122 .

[0039] The power supply 124 is connected to the readout IC 122 via the power supply transmission circuit 123 and supplies power for operating the readout IC 122 .

[0040] 2 shows one semiconductor detection element 121, but the X-ray detector 12 is provided with a plurality of semiconductor detection elements 121 as X-ray detection elements. Also, while Fig. 2 shows an example in which one readout IC 122 is connected to one semiconductor detection element 121 and one power supply 124 is connected to one readout IC 122, the numbers of readout ICs 122 and power supplies 124 included in the X-ray detector 12 are not limited to this. For example, one readout IC 122 may be connected to multiple semiconductor detection elements 121, or one power supply 124 may be connected to multiple readout ICs 122.

[0041] Generally, in such a configuration of the X-ray detector 12, when the dose of X-rays incident on the semiconductor detection element 121 increases, the power consumption of the readout IC 122 changes, which may result in poor reconstructed images or deterioration in quantitativeness.

[0042] FIG. 3 is a schematic diagram showing the circuit operation of the X-ray detector 12 according to the first embodiment when a high dose of X-rays is incident thereon.

[0043] For example, as shown in FIG. 3, it is assumed that the readout IC 122 is a load, the resistance of the power supply transmission circuit 123 is r [Ω], and the voltage of the power supply 124 is V0 [V].

[0044] Here, when the dose of X-rays incident on the semiconductor detection element 121 increases, the number of operations of the readout IC 122 increases, and the current consumption I of the readout IC 122 increases.

[0045] When the current consumption I of the readout IC 122 increases, the power consumption I×r of the power supply transmission circuit 123 increases accordingly, causing a change in the voltage drop in the power supply transmission circuit 123. As a result, the voltage V=V0−I×r supplied to the readout IC 122 fluctuates, and if the discrimination performance of the readout IC 122 is highly sensitive to changes in the voltage V, artifacts may occur in the reconstructed image or the quantitativeness of the reconstructed image may deteriorate.

[0046] For this reason, the X-ray CT apparatus 1 according to this embodiment is configured to be able to prevent defects in reconstructed images and deterioration in quantitativeness caused by changes in the power consumption of the readout IC 122.

[0047] Specifically, in addition to the above-described processing functions, processing circuitry 44 has determination function 445 and notification function 446. Here, determination function 445 is an example of a determination unit, and notification function 446 is an example of a notification unit.

[0048] Before the actual scan is performed, the judgment function 445 judges whether the indicator related to the power consumption of the readout IC 122 in the actual scan exceeds the standard based on the information of the scan plan set for the actual scan and the information obtained by the positioning imaging performed before the actual scan.

[0049] For example, the judgment function 445 estimates the current or voltage consumption of the readout IC 122 during the main scan based on information about the scan plan set for the main scan and information obtained by positioning imaging, and if the current or voltage consumption exceeds a predetermined threshold, judges that the indicator related to the power consumption of the readout IC 122 during the main scan exceeds the standard.

[0050] The notification function 446 notifies the operator when the index relating to the power consumption of the readout IC 122 exceeds the standard in the main scan, according to the result of the determination by the determination function 445.

[0051] That is, before the actual scan is performed, the notification function 446 notifies the operator if an index related to the power consumption of the readout IC 122 during the actual scan exceeds a standard, based on the information of the scan plan set for the actual scan and the information obtained by positioning photography.

[0052] For example, if an index relating to the power consumption of the readout IC 122 exceeds a standard in the main scan, the notification function 446 notifies the operator of information suggesting a change in the scan plan.

[0053] For example, the notification function 446 notifies the operator of information suggesting a change in the scan plan, such as information indicating a scan plan in which the index related to the power consumption of the readout IC 122 falls below the reference value.

[0054] With this configuration, before the actual scan is performed, the power consumption of the readout IC 122 expected during the actual scan can be predicted using information on the scan plan set for the actual scan and information obtained by positioning imaging, thereby making it possible to control the power consumption of the readout IC 122 during the actual scan so that it does not exceed the standard.

[0055] Therefore, according to this embodiment, it is possible to prevent defects in the reconstructed image and deterioration in quantitativeness caused by changes in the power consumption of the readout IC 122.

[0056] The following describes in detail the processing functions of the above-mentioned X-ray CT apparatus 1. Note that, here, an example will be described in which information on a scanogram of a subject captured by positioning imaging is used as information obtained by positioning imaging.

[0057] FIG. 4 is a flowchart showing the processing procedure of the processing performed by the X-ray CT apparatus 1 according to the first embodiment.

[0058] For example, as shown in FIG. 4, in this embodiment, first, the system control function 441 performs positioning imaging in accordance with preset scan conditions for positioning imaging, and captures a scanogram of the subject (step S101).

[0059] Here, a scanogram is CT image data of a subject that is used to determine scan conditions such as the scan range of the subject when setting up a scan plan for the actual scan, and is sometimes called a positioning image or a scout image.

[0060] For example, the system control function 441 fixes the position of the X-ray tube 11 at a predetermined rotation angle, irradiates the subject with X-rays from the X-ray tube 11 while moving the top plate 33 of the bed device 30 in the Z direction, collects detection data, and generates two-dimensional CT image data from the collected detection data, thereby capturing a two-dimensional scanogram of the subject.

[0061] Alternatively, for example, the system control function 441 acquires projection data for the entire circumference of the subject by helical scanning or non-helical scanning, and generates three-dimensional CT image data from the acquired projection data to capture a three-dimensional scanogram of the subject. At this time, the system control function 441 executes a helical scan or non-helical scan at a lower radiation dose than the main scan on a wide range of the subject, such as the entire chest, entire abdomen, entire upper body, or entire body. Here, the non-helical scan may be, for example, a step-and-shoot scan in which the position of the top 33 is moved at regular intervals and scans are performed with the top 33 stopped at multiple positions.

[0062] Alternatively, for example, the system control function 441 may capture a two-dimensional scan image of the subject by generating two-dimensional image data according to an arbitrary direction based on three-dimensional X-ray CT image data generated from projection data for the entire circumference of the subject.

[0063] Next, the system control function 441 sets a scan plan for the main scan based on the input operation received from the operator via the input interface 43 (step S102).

[0064] Here, the scan plan is information that defines the scan conditions, and includes scan parameters such as the tube current supplied to the X-ray tube 11 to irradiate X-rays from the X-ray tube 11, the rotation speed at which the rotating frame 13 that supports the X-ray tube 11 and the X-ray detector 12 rotates, and the scan range of the subject.

[0065] Next, the determination function 445 estimates the current or voltage consumption of the readout IC 122 during the main scan based on the information on the scan plan for the main scan and the information on the scanogram of the subject (step S103).

[0066] For example, based on information on the scanogram of the subject, the determination function 445 derives a water equivalent thickness by converting the thickness of the subject into the thickness of water for each semiconductor detection element 121 included in the X-ray detector 12. For example, the determination function 445 sets the water equivalent thickness to 0 for a semiconductor detection element 121 at a position where the subject is not placed, and derives a water equivalent thickness according to the part of the subject placed on the semiconductor detection element 121 for a semiconductor detection element 121 at a position where the subject is placed.

[0067] Thereafter, the judgment function 445 derives the incident X-ray dose for each semiconductor detection element 121 based on information such as the tube current included in the scan plan information and the water equivalent thickness derived for each semiconductor detection element 121, and derives the current consumption or voltage of the readout IC 122 according to the derived incident X-ray dose.

[0068] For example, the determination function 445 derives the current consumption or voltage of the readout IC 122 during the main scan from the derived incident X-ray dose using a formula that represents the relationship between a predefined incident X-ray dose and the current consumption or voltage of the readout IC 122 during the main scan. Alternatively, the determination function 445 derives the current consumption or voltage of the readout IC 122 during the main scan from the derived incident X-ray dose using a table that associates preset incident X-ray doses with the current consumption or voltage of the readout IC 122 during the main scan.

[0069] The method for estimating the current or voltage consumed by the read IC 122 during the main scan from the scan plan information and the scanogram information is not limited to these, and various other known methods can be used.

[0070] Next, the determination function 445 determines whether the estimated current or voltage consumption of the readout IC 122 exceeds a predetermined threshold value (step S104).

[0071] Here, if the judgment function 445 determines that the current consumption or voltage of the readout IC 122 does not exceed the threshold value (step S104, No), the system control function 441 performs the main scan of the subject in accordance with the set scan plan for the main scan (step S105).

[0072] On the other hand, if the judgment function 445 determines that the current consumption or voltage of the readout IC 122 exceeds the threshold (step S104, Yes), the notification function 446 notifies the operator of a warning and information suggesting a change to the scan plan (step S106).

[0073] For example, the notification function 446 notifies the operator of information indicating a scan plan in which the current consumption or voltage of the readout IC 122 falls below a threshold, as information proposing a change in the scan plan.

[0074] For example, the notification function 446 derives scan parameters (e.g., tube current, etc.) that will cause the current consumption or voltage of the readout IC 122 to fall below a threshold based on information about the scan plan for the actual scan that is set at that time and information about the scan image of the subject, and notifies the operator of information indicating the derived scan parameters.

[0075] At this time, for example, when the determination function 445 determines that the current consumption or voltage of the readout IC 122 exceeds a threshold, the notification function 446 may notify the operator of information suggesting a change in the position of the subject.

[0076] For example, the notification function 446 notifies the operator of information indicating the position of the subject at which the current consumption or voltage of the readout IC 122 falls below a threshold, as information suggesting a change in the position of the subject.

[0077] For example, the notification function 446 derives the position of the subject at which the current consumption or voltage of the readout IC 122 falls below a threshold based on information about the scan plan for the main scan set at that time and information about the scanogram of the subject, and notifies the operator of information indicating the derived position of the subject (e.g., the direction and amount of movement of the subject, etc.).

[0078] Here, the notification function 446 may notify information proposing a change in the position of the subject in addition to the information proposing a change in the scan plan, or may notify information proposing a change in the position of the subject instead of the information proposing a change in the scan plan.

[0079] At this time, for example, the notification function 446 notifies the operator of information suggesting a change in the scan plan or information suggesting a change in the position of the subject by outputting a message to the display 42 of the console device 40 or an information display panel provided on the gantry device 10. For example, the notification function 446 may pop up a window displaying a message indicating the content of each piece of information in the display area of ​​the display 42 or panel.

[0080] Furthermore, for example, the notification function 446 may display information such as the scan parameters and power consumption of the readout IC 122 before the scan plan is changed, and information such as the scan parameters and power consumption of the readout IC 122 after the scan plan is changed in accordance with the proposal on the display 42 or a panel of the gantry device 10, and then receive a response from the operator as to whether or not to accept the proposal.

[0081] For example, the notification function 446 displays information before the change and information after the change, as well as a button or the like for receiving from the operator an operation specifying whether or not to accept the change. If the notification function 446 receives an operation specifying that the change is accepted from the operator via the input interface 43, it may proceed to changing the subsequent scan plan and performing the main scan, and if the notification function 446 receives an operation specifying that the change is not accepted from the operator, it may return to step S102 and set the scan plan again.

[0082] Next, the system control function 441 changes the scan plan for the main scan based on the input operation received from the operator via the input interface 43 (step S107).

[0083] At this time, for example, the operator changes the scan plan for the main scan by inputting scan parameters (for example, tube current, etc.) that will make the current consumption or voltage of the readout IC 122 fall below a threshold value in accordance with the proposed information.

[0084] Then, the system control function 441 performs the main scan of the subject in accordance with the changed scan plan for the main scan (step S105).

[0085] In this embodiment, the processing circuitry 44 is realized by, for example, a processor. In this case, each processing function possessed by the processing circuitry 44 is stored in the memory 41 in the form of, for example, a program executable by a computer. The processing circuitry 44 then reads each program from the memory 41 and executes it to realize the function corresponding to each program. In other words, the processing circuitry 44 in a state in which each program has been read has each processing function shown in the processing circuitry 44 of FIG. 1.

[0086] 4, for example, the processes of steps S101, S102, S105, and S107 are realized by, for example, the processing circuitry 44 reading out from the memory 41 a predetermined program corresponding to the system control function 441 and executing it. Also, the processes of steps S103 and S104 are realized by, for example, the processing circuitry 44 reading out from the memory 41 a predetermined program corresponding to the determination function 445 and executing it. Also, the process of step S106 is realized by, for example, the processing circuitry 44 reading out from the memory 41 a predetermined program corresponding to the notification function 446 and executing it.

[0087] As described above, in the first embodiment, the determination function 445 determines whether the index related to the power consumption of the readout IC 122 during the main scan exceeds the standard based on the information of the scan plan set for the main scan and the information obtained by the positioning imaging before the main scan is executed. Furthermore, the notification function 446 notifies the operator when the index related to the power consumption of the readout IC 122 during the main scan exceeds the standard, depending on the result of the determination by the determination function 445.

[0088] With this configuration, before the actual scan is performed, the power consumption of the readout IC 122 expected during the actual scan can be predicted using information on the scan plan set for the actual scan and information obtained by positioning imaging, thereby making it possible to control the power consumption of the readout IC 122 during the actual scan so that it does not exceed the standard.

[0089] Therefore, according to the first embodiment, it is possible to prevent defects in the reconstructed image and deterioration in quantitativeness caused by changes in the power consumption of the readout IC 122.

[0090] Furthermore, it is possible to avoid re-examination due to defects in the reconstructed image or deterioration in quantitativeness caused by changes in the current consumption or voltage of the readout IC 122.

[0091] Furthermore, in the first embodiment, when the index relating to the power consumption of the readout IC 122 exceeds the reference value in the main scan, the notification function 446 notifies the operator of information suggesting a change in the scan plan.

[0092] This allows the operator to change the scan plan in accordance with the proposal, thereby enabling a highly quantitative state to be maintained while obtaining a reconstructed image.

[0093] (Second embodiment) In the first embodiment described above, the power consumption of the readout IC 122 is determined using information from the scanned image of the subject. However, if the subject moves after the scanned image is captured, for example, it may be necessary to re-determine the power consumption of the readout IC 122.

[0094] Therefore, in the following, as a second embodiment, an example will be described in which the X-ray CT device 1 is configured to notify the operator when a state arises in which re-determination of the power consumption of the readout IC 122 is required due to movement of the subject. Note that in the following, the second embodiment will be described mainly with respect to the differences from the first embodiment, and detailed description of overlapping contents will be omitted.

[0095] Specifically, in this embodiment, the notification function 446 further notifies the operator if the subject moves between the time when the positioning image is taken and the time when the main scan is taken, resulting in a state where the index related to the power consumption of the readout IC 122 needs to be re-evaluated.

[0096] Hereinafter, a detailed description will be given of the processing performed by the X-ray CT apparatus 1 according to this embodiment. Note that, as in the first embodiment, an example will be described in which information on a scanogram of a subject captured by positioning imaging is used as information obtained by positioning imaging.

[0097] FIG. 5 is a flowchart showing the processing procedure of the processing performed by the X-ray CT apparatus 1 according to the second embodiment.

[0098] For example, as shown in FIG. 5, in this embodiment, first, the system control function 441 performs positioning imaging in accordance with the preset scan conditions for positioning imaging, as in the first embodiment, to capture a scanogram of the subject (step S201).

[0099] Then, similarly to the first embodiment, the system control function 441 sets a scan plan for the main scan based on an input operation received from the operator via the input interface 43 (step S202).

[0100] Next, the determination function 445 estimates the current or voltage consumption of the readout IC 122 during the main scan based on the information on the scan plan for the main scan and the information on the scanogram of the subject, as in the first embodiment (step S203).

[0101] Then, the determination function 445 determines whether the estimated current or voltage consumption of the read IC 122 exceeds a predetermined threshold value, as in the first embodiment (step S204).

[0102] Here, in this embodiment, if the judgment function 445 determines that the current consumption or voltage of the readout IC 122 does not exceed the threshold value (step S204, No), it further determines whether the subject has moved after the scan image was taken (step S205).

[0103] For example, the determination function 445 determines whether the subject has moved based on a camera image captured by a camera provided at a position where the subject placed on the top board 33 can be imaged. In this case, the camera may be provided on the gantry 10 (for example, the inner wall of a hole into which the top board 33 of the gantry 10 is inserted or the front cover of the gantry 10), or may be placed in an imaging room in which the X-ray CT apparatus 1 is installed (for example, the ceiling or wall of the imaging room). For example, the camera continuously captures camera images of the subject while imaging is being performed.

[0104] Then, if the judgment function 445 determines that the subject is not moving (step S205, No), the system control function 441 performs a main scan of the subject in accordance with the set scan plan for the main scan, as in the first embodiment (step S206).

[0105] On the other hand, if the judgment function 445 determines that the current consumption or voltage of the readout IC 122 exceeds the threshold value (step S204, Yes), as in the first embodiment, the notification function 446 notifies the operator of a warning and information suggesting a change to the scan plan (step S207).

[0106] Then, similarly to the first embodiment, the system control function 441 changes the scan plan for the main scan based on the input operation received from the operator via the input interface 43 (step S208).

[0107] Thereafter, the determination function 445 determines whether or not the subject has moved after the scanogram was taken (step S205).

[0108] Then, if the judgment function 445 determines that the subject is not moving (step S205, No), the system control function 441 performs a main scan of the subject in accordance with the changed scan plan for the main scan, as in the first embodiment (step S206).

[0109] On the other hand, if the judgment function 445 determines that the subject has moved (step S205, Yes), the notification function 446 determines that a re-evaluation of the indicators related to the power consumption of the readout IC 122 is required, and notifies the operator of information urging them to perform positioning imaging again (step S209), and ends the imaging process.

[0110] For example, the notification function 446 notifies the operator of information urging the operator to re-perform the positioning imaging by outputting a message to the display 42 of the console device 40 or to an information display panel provided on the gantry device 10. For example, the notification function 446 may pop up a window displaying a message urging the operator to re-perform the positioning imaging in the display area of ​​the display 42 or the panel.

[0111] In the above-described processing procedure, the determination function 445 determines in step S204 whether the current consumption or voltage of the readout IC 122 exceeds a predetermined threshold, and then determines in step S205 whether the subject has moved after the scanogram has been captured. However, for example, these determinations may be performed in parallel. In that case, the notification function 446 notifies the operator of information urging the operator to perform positioning imaging again when the determination function 445 determines that the subject has moved, and ends the imaging process.

[0112] In this embodiment, the processing circuitry 44 is also realized by, for example, a processor. In this case, each processing function possessed by the processing circuitry 44 is stored in the memory 41 in the form of, for example, a program executable by a computer. The processing circuitry 44 then reads each program from the memory 41 and executes it to realize the function corresponding to each program. In other words, the processing circuitry 44 in a state in which each program has been read has each processing function shown in the processing circuitry 44 of FIG. 1.

[0113] 5, the processes of steps S201, S202, S206, and S208 are realized, for example, by the processing circuitry 44 reading out from the memory 41 a predetermined program corresponding to the system control function 441 and executing it. Furthermore, the processes of steps S203, S204, and S205 are realized, for example, by the processing circuitry 44 reading out from the memory 41 a predetermined program corresponding to the determination function 445 and executing it. Furthermore, the processes of steps S207 and S209 are realized, for example, by the processing circuitry 44 reading out from the memory 41 a predetermined program corresponding to the notification function 446 and executing it.

[0114] As described above, in the second embodiment, the notification function 446 further notifies the operator when the subject moves between the time when the positioning image is taken and the time when the main scan is taken, resulting in a state where the power consumption of the readout IC 122 needs to be re-evaluated.

[0115] With this configuration, it is possible to control the power consumption of the readout IC 122 during the actual scan so that it does not exceed the standard, while also taking into consideration the case where the subject moves after the scanogram is captured.

[0116] The first and second embodiments have been described above, but each embodiment can be implemented by appropriately modifying part of the above-described configuration. Therefore, several variations of the above-described embodiments will be described below. Note that the following description will focus on differences from the above-described embodiments, and detailed description of overlapping content will be omitted.

[0117] (First Modification) For example, in the above-described embodiment, an example has been described in which information on a scan image of the subject is used as information obtained by positioning imaging, but the embodiment is not limited to this.

[0118] For example, information obtained by positioning imaging may be information on a camera image of the subject captured by a camera during positioning imaging.

[0119] In this case, the camera that captures the camera images of the subject may be provided on the gantry 10 (for example, the inner wall of the hole into which the top plate 33 of the gantry 10 is inserted or the front cover of the gantry 10), or may be placed in the imaging room (for example, the ceiling or wall of the imaging room) in which the X-ray CT apparatus 1 is installed. For example, the camera continuously captures camera images of the subject while imaging is being performed.

[0120] Then, the determination function 445 estimates the current or voltage consumption of the readout IC 122 during the main scan based on the information on the scan plan for the main scan and the information on the camera image of the subject.

[0121] For example, based on information on a camera image of the subject, the determination function 445 derives a water equivalent thickness by converting the thickness of the subject into the thickness of water for each semiconductor detection element 121 included in the X-ray detector 12. For example, the determination function 445 sets the water equivalent thickness to 0 for a semiconductor detection element 121 at a position where the subject is not placed, and derives a water equivalent thickness according to the part of the subject placed on the semiconductor detection element 121 for a semiconductor detection element 121 at a position where the subject is placed.

[0122] Thereafter, the judgment function 445 derives the incident X-ray dose for each semiconductor detection element 121 based on information such as the tube current included in the scan plan information and the water equivalent thickness derived for each semiconductor detection element 121, and derives the current consumption or voltage of the readout IC 122 according to the derived incident X-ray dose.

[0123] For example, the determination function 445 derives the current consumption or voltage of the readout IC 122 during the main scan from the derived incident X-ray dose using a formula that represents the relationship between a predefined incident X-ray dose and the current consumption or voltage of the readout IC 122 during the main scan. Alternatively, the determination function 445 derives the current consumption or voltage of the readout IC 122 during the main scan from the derived incident X-ray dose using a table that associates preset incident X-ray doses with the current consumption or voltage of the readout IC 122 during the main scan.

[0124] Thereafter, the determination function 445 determines whether the estimated current or voltage consumption of the readout IC 122 exceeds a predetermined threshold.

[0125] For example, the determination function 445 continuously derives the current consumption or voltage of the readout IC 122 based on camera images of the subject continuously captured by the camera, and determines that the current consumption or voltage of the readout IC 122 has exceeded a predetermined threshold when the derived current consumption or voltage exceeds a threshold.

[0126] Then, when the determination function 445 determines that the current consumption or voltage of the readout IC 122 exceeds a predetermined threshold, the notification function 446 notifies the operator of information suggesting a change in the scan plan or information suggesting a change in the position of the subject.

[0127] The determination function 445 may not only determine the current or voltage consumption of the readout IC 122 during the main scan based on the camera image of the subject, but also determine whether the subject is outside the X-ray irradiation range.

[0128] In this case, for example, the notification function 446 notifies the operator of information suggesting a change in the position of the subject when the determination function 445 determines that the subject is outside the X-ray irradiation range. For example, the notification function 446 derives, based on the camera image, a movement direction and amount of movement of the subject to move the subject so as to enter the X-ray irradiation range, and notifies the operator of information indicating the derived movement direction and amount of movement.

[0129] Here, for example, if the judgment function 445 determines that the current consumption or voltage of the readout IC 122 exceeds a predetermined threshold, the notification function 446 may notify the operator that the position of the subject needs to be changed due to the power consumption of the readout IC 122, or if the judgment function 445 determines that the subject is outside the X-ray irradiation range, may notify the operator that the position of the subject needs to be changed due to the X-ray irradiation range.In this way, the notification function 446 may notify the operator of information suggesting a change in the position of the subject in combination with the cause.

[0130] (Second Modification) Furthermore, in the above-described embodiment and modified examples, examples have been described in which scanned images or camera images of the subject are used as information obtained by positioning imaging, but the embodiment is not limited to this.

[0131] For example, information obtained by positioning imaging may be information on the current consumption or voltage of the readout IC 122 measured during positioning imaging.

[0132] In this case, for example, the current consumption or voltage of the readout IC 122 is measured using a monitoring circuit provided inside the X-ray detector 12 or between the X-ray detector 12 and the DAS 18. The monitoring circuit is connected to the readout IC 122 or the power supply 124 of the X-ray detector 12, and measures the current consumption or voltage of the readout IC 122 during positioning imaging, and transmits information on the measured current consumption or voltage consumption to the determination function 445 of the processing circuit 44.

[0133] Then, the determination function 445 estimates the current or voltage consumption of the readout IC 122 during the main scan based on the information on the scan plan for the main scan and the information on the current or voltage consumption of the readout IC 122 measured during positioning imaging.

[0134] For example, the determination function 445 derives the current or voltage consumed by the read IC 122 during the main scan from the current or voltage consumed by the read IC 122 during the positioning scan using a predefined formula that represents the relationship between the current or voltage consumed by the read IC 122 during the positioning scan and the current or voltage consumed by the read IC 122 during the main scan. Alternatively, the determination function 445 derives the current or voltage consumed by the read IC 122 during the main scan from the current or voltage consumed by the read IC 122 during the positioning scan using a predefined table that associates the current or voltage consumed by the read IC 122 during the positioning scan with the current or voltage consumed by the read IC 122 during the main scan.

[0135] Here, for example, the relational expression or table used to derive the current or voltage consumed by the readout IC 122 during the main scan is defined for each of a plurality of tube current values ​​or ranges, and the determination function 445 derives the current or voltage consumed by the readout IC 122 during the main scan using the relational expression or table corresponding to the tube current included in the scan plan information.

[0136] (Third Modification) Furthermore, in the above-described embodiment, an example has been described in which one readout IC 122 is connected to one semiconductor detection element 121 in the X-ray detector 12, and one readout IC 122 is connected to one power supply 124, but the embodiment is not limited to this.

[0137] For example, as described above, one readout IC 122 may be connected to a plurality of semiconductor detection elements 121, and one power supply 124 may be connected to a plurality of readout ICs 122.

[0138] Here, for example, when one readout IC 122 is connected to multiple semiconductor detection elements 121, the determination function 445 derives and sums the incident X-ray doses of the multiple semiconductor detection elements 121 connected to one readout IC 122, and derives the current consumption or voltage during the main scan of the readout IC 122 based on the sum of the incident doses. Then, the determination function 445 determines for each readout IC 122 whether the derived current consumption or voltage exceeds a threshold value.

[0139] Furthermore, for example, when one power supply 124 is connected to multiple readout ICs 122, the determination function 445 derives and adds up the current consumption or voltage of each of the multiple readout ICs 122 connected to one power supply 124, thereby deriving the current consumption or voltage during the main scan of the readout IC 122 connected to that power supply 124. Then, the determination function 445 determines for each power supply 124 whether the derived current consumption or voltage exceeds a threshold value.

[0140] (Fourth Modification) Furthermore, in the above-described embodiment, an example has been described in which both the information on the scan plan set for the main scan and the information obtained by the positioning imaging are used, but the embodiment is not limited to this.

[0141] For example, the determination function 445 may determine whether the index related to the power consumption of the readout IC 122 in the main scan exceeds a reference value based only on the information of the scan plan set for the main scan. In this case, the determination function 445 derives the total incident dose of the X-ray detector 12 on the assumption that all of the X-rays irradiated from the X-ray tube 11 according to the scan plan set for the main scan are not absorbed by the subject and are incident on the X-ray detector 12.

[0142] Alternatively, for example, the determination function 445 may determine whether the index related to the power consumption of the readout IC 122 in the main scan exceeds the reference value based only on the information obtained by the positioning imaging. In this case, the determination function 445 derives the incident dose of the entire X-ray detector 12, assuming that the maximum dose of X-rays that can be used by the system is set as the scan plan for the main scan.

[0143] That is, before the actual scan is performed, the judgment function 445 judges whether or not the index relating to the power consumption of the readout IC 122 in the actual scan exceeds the standard based on at least one of the information of the scan plan set for the actual scan and the information obtained by positioning photography.

[0144] (Fifth Modification) In addition, in the above-described embodiment, an example has been described in which the X-ray detector 12 is a photon-counting detector, i.e., a direct conversion type detector having, as a detection element, a semiconductor detection element 121 that converts incident X-rays into an electrical signal, but the embodiment is not limited to this.

[0145] For example, the X-ray detector 12 may be an indirect detector having a scintillator and a photosensor as X-ray detection elements. Here, the scintillator has a scintillator crystal that outputs light with a photon quantity corresponding to the dose of incident X-rays. The photosensor is realized by a photomultiplier tube (PMT) or the like, and outputs an electrical signal corresponding to the photon quantity of light output from the scintillator crystal of the scintillator.

[0146] In this case, the X-ray detector 12 has a readout circuit that reads and processes the electrical signals output from the optical sensor of the X-ray detection element, a power supply that supplies power to operate the readout circuit, and a power transmission circuit that transmits the power supplied from the power supply to the readout circuit.

[0147] (Sixth Modification) In the above-described embodiment, the processing circuitry 44 has the determination function 445, but the embodiment is not limited to this.

[0148] For example, the multiple processes performed by the judgment function 445 may be distributed and executed by a processing circuit provided inside the X-ray detector 12 or between the X-ray detector 12 and the DAS 18, the DAS 18, and the processing circuit 44.

[0149] For example, a processing circuit provided inside the X-ray detector 12 or between the X-ray detector 12 and the DAS 18, or the DAS 18, estimates the current or voltage consumption of the readout IC 122 during the main scan and transmits information on the estimated current or voltage consumption to the processing circuit 44. Then, based on the received information on current or voltage consumption, the processing circuit 44 determines that the index related to the power consumption of the readout IC 122 during the main scan exceeds a reference if the current or voltage consumption exceeds a predetermined threshold.

[0150] (Other embodiments) In the above-described embodiment, each processing function is realized by a single processing circuit 44, but the embodiment is not limited thereto. For example, the processing circuit 44 may be configured by combining multiple independent processors, and each processor may execute a program to realize each of the above-described processing functions. Furthermore, each processing function of the processing circuit 44 may be realized by being appropriately distributed or integrated among a single or multiple processing circuits. Furthermore, each processing function of the processing circuit 44 may be realized by a combination of hardware and software, such as circuits. In addition, while the above-described example illustrates a case in which a single memory 41 stores programs corresponding to each processing function, the embodiment is not limited thereto. For example, multiple memories may be distributed, and the processing circuit 44 may read and execute corresponding programs from the individual memories.

[0151] Although the above description describes an example in which a "processor" reads and executes a program corresponding to each processing function from a memory, the embodiment is not limited to this. The term "processor" refers to a circuit such as a central processing unit (CPU), a graphics processing unit (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)). If the processor is a CPU, for example, the processor realizes each processing function by reading and executing a program stored in a memory. On the other hand, if the processor is an ASIC, instead of storing a program in a memory, the processing function is directly incorporated into the processor circuit as a logic circuit. Note that each processor in this embodiment is not limited to being configured as a single circuit for each processor, but may be configured as a single processor by combining multiple independent circuits to realize its processing function. Furthermore, the multiple components in FIG. 1 may be integrated into a single processor to realize the processing functions.

[0152] Here, the program executed by the processor is provided in advance in a read-only memory (ROM) or other memory. The program may be provided by being recorded on a computer-readable, non-transitory storage medium such as a compact disk (CD)-ROM, a flexible disk (FD), a recordable CD-R (CD-R), or a digital versatile disk (DVD) in a format that can be installed or executed on these devices. The program may also be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. For example, the program may be composed of modules including the above-mentioned functional units. In actual hardware, a CPU reads and executes the program from a storage medium such as a ROM, whereby each module is loaded into a main memory device and generated on the main memory device.

[0153] In the above-described embodiments, the components of each device shown in the drawings are conceptual functional units and do not necessarily have to be physically configured as shown. In other words, the specific form of distribution or integration of each device is not limited to that shown in the drawings, and all or part of the devices can be functionally or physically distributed or integrated in any unit depending on various loads, usage conditions, etc. Furthermore, all or any part of the processing functions performed by each device can be realized by a CPU and a program analyzed and executed by the CPU, or can be realized as hardware using wired logic.

[0154] Furthermore, among the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically using a known method.In addition, the information including the processing procedures, control procedures, specific names, various data and parameters shown in the above documents and drawings can be changed as desired unless otherwise specified.

[0155] According to at least one of the embodiments described above, it is possible to prevent defects in reconstructed images and deterioration in quantitativeness caused by changes in power consumption of the readout circuit.

[0156] 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. [Explanation of symbols]

[0157] 1 X-ray CT device 12 X-ray detector 121 Semiconductor detector 122 Readout IC 44 Processing circuit 445 Judgment Function 446 Notification function

Claims

1. an X-ray detection element for detecting X-rays; a readout circuit that reads out an output signal from the X-ray detection element; a determination unit that determines, before execution of a main scan, whether or not an index related to power consumption of the readout circuit in the main scan exceeds a reference value based on at least one of information on a scan plan set for the main scan and information obtained by positioning imaging; An X-ray computed tomography apparatus comprising:

2. and a notification unit that notifies an operator when an index related to power consumption of the readout circuit in the main scan exceeds the reference value according to a result of the determination by the determination unit.

2. The X-ray computed tomography apparatus according to claim 1.

3. the determination unit estimates a current consumption or a voltage consumption of the readout circuit during the main scan based on at least one of information on the scan plan and information obtained by the positioning imaging, and determines that an index related to power consumption of the readout circuit during the main scan exceeds the reference when the current consumption or the voltage consumption exceeds a predetermined threshold.

3. An X-ray computed tomography apparatus according to claim 1 or 2.

4. an X-ray detection element for detecting X-rays; a readout circuit that reads out an output signal from the X-ray detection element; a notification unit that notifies an operator when an index related to power consumption of the readout circuit in the main scan exceeds a reference value based on at least one of information on a scan plan set for the main scan and information obtained by positioning imaging before the main scan is executed; An X-ray computed tomography apparatus comprising:

5. the notification unit notifies the operator of information suggesting a change in the scan plan when an index related to the power consumption of the readout circuit in the main scan exceeds the reference value.

5. An X-ray computed tomography apparatus according to claim 2 or 4.

6. the notification unit notifies the operator of information indicating a scan plan in which an index related to power consumption of the readout circuit falls below the reference, as information proposing a change to the scan plan.

6. An X-ray computed tomography apparatus according to claim 5.

7. The information obtained by the positioning imaging is information on a scanogram of the subject imaged by the positioning imaging.

5. An X-ray computed tomography apparatus according to claim 1 or 4.

8. The information obtained by the positioning imaging is information on a camera image of the subject captured by a camera during the positioning imaging.

5. An X-ray computed tomography apparatus according to claim 1 or 4.

9. the information obtained by the positioning imaging is information about the current consumption or voltage of the readout circuit measured during the positioning imaging; 5. An X-ray computed tomography apparatus according to claim 1 or 4.

10. 1. A control method for an X-ray computed tomography apparatus having an X-ray detection element that detects X-rays and a readout circuit that reads out an output signal of the X-ray detection element, comprising: a determining step of determining, before execution of a main scan, whether or not an index related to power consumption of the readout circuit in the main scan exceeds a reference value based on at least one of information on a scan plan set for the main scan and information obtained by positioning imaging; a notification step of notifying an operator when an index relating to power consumption of the readout circuit in the main scan exceeds the reference value according to a result of the determination in the determination step; A control method comprising:

Images