X-ray CT device, control method for X-ray CT device, and program

Abstract

To start reconstruction processing sooner in an X-ray CT apparatus of a two-step transfer system.SOLUTION: An X-ray CT apparatus acquires projection data on a subject on the basis of X-ray detection data by biological information synchronous scanning, and generates a CT image of the subject on the basis of the projection data. The X-ray CT apparatus includes a first acquisition part, a determination part, and a second acquisition part. The first acquisition part acquires biological information on the subject at a timing that the biological information synchronous scanning is executed. The determination part determines, as preferential data, detection data for which data transfer is executed preferentially out of the X-ray detection data acquired in the biological information synchronous scanning on the basis of the biological information. The second acquisition part acquires the preferential data from a storage device that holds the detection data.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Conventionally, there are X-ray CT (Computed Tomography) devices that generate cross-sectional images of a subject using X-rays. There are two types of X-ray CT devices: one that collects and transfers projection data in parallel, and one that transfers the data after acquiring the projection data. The latter method (hereinafter referred to as the "two-stage transfer method") was devised because the former method has become difficult to transfer data in real time as the volume of projection data increases, but it takes longer to complete data transfer than the former method. In recent years, X-ray CT devices have also been developed that can generate cross-sectional images that are less affected by the subject's movement by using ECG-gated scanning, which acquires projection data at a timing when the subject's movement is minimal, based on the subject's ECG waveform.

[0003] However, a two-stage transmission X-ray CT scanner requires a lot of time. Furthermore, when ECG-gated scanning is performed using a helical scan, the helical pitch must be shorter than that of a normal helical scan in order to ensure reconstruction in all phases, which increases the amount of data acquired and requires more time for data transmission. For these reasons, when ECG-gated scanning is performed using an X-ray CT scanner using a two-stage transmission method, it takes a long time to acquire and transmit projection data, making it impossible to perform reconstruction processing in the target phase immediately after the examination is completed, which may result in a long time being required to determine whether the examination was successful. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-000315 A [Patent Document 2] Japanese Patent Application Publication No. 138680 / 1983 [Patent Document 3] JP 2019-093137 A [Patent Document 4] JP 2004-000356 A Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the embodiments disclosed in this specification and the drawings is to complete reconstruction processing more quickly in an X-ray CT apparatus using a two-stage transfer method, and to quickly determine whether the examination has been successful. However, the problem to be solved by the embodiments disclosed in this specification and the drawings is not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0006] An X-ray CT apparatus according to an embodiment acquires projection data of a subject based on X-ray detection data obtained by a biometric information synchronous scan, and generates a CT image of the subject based on the projection data. The X-ray CT apparatus has a first acquisition unit, a determination unit, and a second acquisition unit. The first acquisition unit acquires biometric information of the subject at a timing when the biometric information synchronous scan is performed. The determination unit determines, based on the biometric information, detection data to be preferentially transferred from among the X-ray detection data acquired in the biometric information synchronous scan, as priority data. The second acquisition unit acquires the priority data from a storage device that holds the detection data. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of the arrangement of an X-ray CT apparatus according to a first embodiment. [Diagram 2] FIG. 1 is a diagram showing an example of an electrocardiogram. [Diagram 3]FIG. 11 is a diagram showing an example of a method for determining priority data based on phase information. [Figure 4] 5 is a conceptual diagram showing a method of transferring X-ray CT apparatus priority data from a gantry device to a console device according to the first embodiment. [Diagram 5] 11 is a flowchart showing an example of a processing flow in which the X-ray CT apparatus determines priority data. [Figure 6] FIG. 13 is a diagram showing an example of the arrangement of an X-ray CT apparatus according to a second embodiment. [Figure 7] 11 is a flowchart showing an example of a processing flow in which the X-ray CT apparatus determines priority data. [Figure 8] 13 is a conceptual diagram showing a method in which the X-ray CT apparatus of the second embodiment transfers priority data from the gantry device to the console device. [Figure 9] FIG. 13 is a conceptual diagram illustrating a case where the transfer method according to the first embodiment is applied to data transfer from a DAS 16 to a receiver 23. [Figure 10] FIG. 13 is a conceptual diagram when the transfer method of the second embodiment is applied to data transfer from a DAS 16 to a receiver 23. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an X-ray CT apparatus, a control method for the X-ray CT apparatus, and a program according to an embodiment will be described with reference to the drawings.

[0009] (First embodiment) FIG. 1 is a diagram showing a configuration example of an X-ray CT device 1A according to the first embodiment. The X-ray CT device 1A includes, for example, a gantry device 10, a bed device 30, and a console device 40. In FIG. 1, for convenience of explanation, both a view of the gantry device 10 seen from the Z-axis direction and a view of the gantry device 10 seen from the X-axis direction are shown, but in reality, there is only one gantry device 10. In the embodiment, the rotation axis of the rotating frame 17 in a non-tilted state or the longitudinal direction of the top plate 33 of the bed device 30 is defined as the Z-axis direction, an axis perpendicular to the Z-axis direction and horizontal to the floor surface is defined as the X-axis direction, and a direction perpendicular to the Z-axis direction and perpendicular to the floor surface is defined as the Y-axis direction. The X-ray CT device 1A captures a contrast CT image (hereinafter simply referred to as a "CT image") for image diagnosis by ECG-gated helical scanning. ECG-gated helical scanning is an example of "biological information synchronous scanning".

[0010] The gantry device 10 has, for example, an X-ray tube 11, a wedge 12, a collimator 13, an X-ray high voltage device 14, an X-ray detector 15, a data acquisition system (hereinafter referred to as DAS: Data Acquisition System) 16, a rotating frame 17, a control device 18, and an electrocardiograph 21.

[0011] X-ray tube 11 generates X-rays by irradiating thermoelectrons from a cathode (filament) to an anode (target) when a high voltage is applied from X-ray high voltage device 14. X-ray tube 11 includes a vacuum tube. For example, X-ray tube 11 is a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermoelectrons.

[0012] The wedge 12 is a filter for adjusting the amount of X-rays irradiated from the X-ray tube 11 to the subject P who is the subject of image diagnosis. The wedge 12 attenuates the X-rays passing through it so that the distribution of the amount of X-rays irradiated from the X-ray tube 11 to the subject P becomes a predetermined distribution. The wedge 12 is also called a wedge filter or a bow-tie filter. The wedge 12 is, for example, made by processing aluminum so as to have a predetermined target angle and a predetermined thickness.

[0013] The collimator 13 is a mechanism for narrowing down the irradiation range of the X-rays transmitted through the wedge 12. The collimator 13 narrows down the irradiation range of the X-rays, for example, by forming a slit by combining multiple lead plates. The collimator 13 is sometimes called an X-ray aperture. The focusing range of the collimator 13 may be mechanically drivable.

[0014] The X-ray high voltage device 14 has, for example, a high voltage generator and an X-ray control device. The high voltage generator has an electric circuit including a transformer and a rectifier, and generates a high voltage to be applied to the X-ray tube 11. The X-ray control device controls the output voltage of the high voltage generator according to the amount of X-rays to be generated by the X-ray tube 11. The high voltage generator may be one that performs voltage boosting using the above-mentioned transformer, or one that performs voltage boosting using an inverter. The X-ray high voltage device 14 may be provided on the rotating frame 17, or on the side of the fixed frame (not shown) of the gantry device 10.

[0015] The X-ray detector 15 detects the intensity of X-rays generated by the X-ray tube 11 and incident upon the subject P. The X-ray detector 15 outputs an electrical signal (which may be an optical signal, etc.) corresponding to the intensity of the detected X-rays to the DAS 16. The X-ray detector 15 has, for example, multiple rows of X-ray detection elements. Each of the multiple rows of X-ray detection elements has multiple X-ray detection elements arranged in the channel direction along an arc centered on the focal point of the X-ray tube 11. The multiple rows of X-ray detection elements are arranged in the slice direction (column direction, row direction).

[0016] The X-ray detector 15 is an indirect detector having, for example, a grid, a scintillator array, and an optical sensor array. The scintillator array has a plurality of scintillators. Each scintillator has a scintillator crystal. The scintillator crystal emits an amount of light according to the intensity of the incident X-ray. The grid is disposed on the surface of the scintillator array on which the X-ray is incident, and has an X-ray shielding plate having a function of absorbing scattered X-rays. The grid may also be called a collimator (one-dimensional collimator or two-dimensional collimator). The optical sensor array has, for example, an optical sensor such as a photomultiplier tube (PMT). The optical sensor array outputs an electric signal according to the amount of light emitted by the scintillator. The X-ray detector 15 may be a direct conversion detector having a semiconductor element that converts the incident X-ray into an electric signal.

[0017] The DAS 16 includes, for example, an amplifier, an integrator, and an A / D converter. The amplifier performs an amplification process on the electrical signal output by each X-ray detection element of the X-ray detector 15. The integrator integrates the amplified electrical signal over a view period. The A / D converter converts the electrical signal indicating the integration result into a digital signal. The DAS 16 outputs detection data of the X-ray detector 15 based on the digital signal to the console device 40. Note that, since X-rays are intermittently irradiated in an ECG-gated helical scan, the detection data output by the DAS 16 includes data indicating that X-rays have been detected and data indicating that X-rays have not been detected (see FIG. 4).

[0018] The rotating frame 17 supports the X-ray tube 11, the wedge 12, the collimator 13, and the X-ray detector 15 in opposing relation to each other. The rotating frame 17 is an annular member having both circular side surfaces with a circular opening formed in the center, an inner side surface connecting the inner circles on both sides, and an outer side surface connecting the outer circles on both sides. Both side surfaces of the rotating frame 17 are flat, and the inner and outer sides are curved.

[0019] The rotating frame 17 is an annular member that supports the X-ray tube 11, the wedge 12, the collimator 13, and the X-ray detector 15 in opposing relation to each other. The rotating frame 17 is supported by a fixed frame (not shown) so as to be rotatable about the subject P introduced inside. The rotating frame 17 also supports the DAS 16. Detection data output by the DAS 16 is transmitted by optical communication from a transmitter having a light-emitting diode (LED) provided on the rotating frame 17 to a receiver 23 having a photodiode provided on a non-rotating part (e.g., a fixed frame) of the gantry device 10, and is transferred to the console device 40 by the receiver 23. The receiver 23 includes a memory that stores the detection data received from the transmitter at least until it is transferred to the console device 40. Note that the method of transmitting detection data from the rotating frame 17 to the non-rotating part is not limited to the method using optical communication described above, and any non-contact type transmission method may be adopted. The rotating frame 17 is not limited to an annular member, and may be an arm-like member as long as it can support and rotate the X-ray tube 11, etc.

[0020] The X-ray CT device 1A is, for example, a Rotate / Rotate-type X-ray CT device (third generation CT) in which both the X-ray tube 11 and the X-ray detector 15 are supported by a rotating frame 17 and rotate around the subject P, but is not limited to this and may be a Stationary / Rotate-type X-ray CT device (fourth generation CT) in which a plurality of X-ray detection elements arranged in a circular ring shape are fixed to a fixed frame and the X-ray tube 11 rotates around the subject P.

[0021] The control device 18 has, for example, a processing circuit having a processor such as a CPU (Central Processing Unit), and a driving mechanism including a motor, an actuator, etc. The processing circuit realizes these functions by, for example, a hardware processor executing a program stored in a storage device (storage circuit).

[0022] The hardware 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) or a complex programmable logic device (CPLD), or a field programmable gate array (FPGA). Instead of storing a program in a storage device, the program may be directly embedded in the circuit of the hardware processor. In this case, the hardware processor realizes a function by reading and executing the program embedded in the circuit. The hardware processor is not limited to being configured as a single circuit, and may be configured as one hardware processor by combining multiple independent circuits to realize each function. The storage device may be a non-transitory (hardware) storage medium. Furthermore, multiple components may be integrated into one hardware processor to realize each function.

[0023] The control device 18, for example, rotates the rotating frame 17, tilts the gantry of the gantry device 10, moves the top plate 33 of the bed device 30 by vertical movement or the like, and radiates (exposes) X-rays from the X-ray tube 11. The control device 18 may be provided in the gantry device 10 or in the console device 40.

[0024] The electrocardiograph 21 detects, by the probe 22, a weak electric current generated by the excitation of the heart of the subject P. The electrocardiograph 21 outputs the time change of the detected electric current as an electrocardiogram. The electrocardiogram is an example of "biological information." The electrocardiogram is used by the X-ray CT device 1A to determine the timing of exposing the subject P to X-rays in an ECG-gated helical scan. The electrocardiogram is also used to determine which data (hereinafter referred to as "priority data") is to be preferentially transferred to the receiver 23 or the console device 40 from among the detection data acquired by the ECG-gated helical scan.

[0025] FIG. 2 is a diagram showing an example of an electrocardiogram. In an electrocardiogram, characteristic waveforms such as P waves, Q waves, R waves, S waves, and T waves appear within a cardiac cycle. FIG. 2 shows an example of an electrocardiogram using the most characteristic R wave. In the R wave, after a substantially fixed time, a systole occurs in which the heart contracts. This systole is followed by a relaxation period in which the heart expands. These contraction and relaxation periods are periods in which the size of the heart fluctuates drastically. The period from immediately after the relaxation period to immediately before the contraction period of the next cardiac cycle is called an isovolumic relaxation period, in which the change in the size of the heart is relatively gentle.

[0026] ECG-gated helical scanning is a scanning method for acquiring projection data at a timing when the time change of the electrocardiogram waveform is small during this relaxation period. ECG-gated helical scanning includes a method for collecting projection data at the timing from projection data acquired at multiple phases, and a method for determining an intermittent X-ray exposure period (hereinafter referred to as "X-ray exposure period") at the timing and exposing the subject P to X-rays during the X-ray exposure period. In either case, an electrocardiogram is acquired when scanning the subject P, and projection data required for reconstruction is identified based on the electrocardiogram waveform shown by the acquired electrocardiogram.

[0027] In addition, since it is assumed that the X-ray exposure period may differ depending on the individual subject P or the condition of the subject P at the time of the examination, when determining the X-ray exposure period, an electrocardiogram of the subject P may be obtained before the scan is performed, and the X-ray exposure period may be determined based on the electrocardiogram obtained there. Here, in order to distinguish it from the electrocardiogram obtained at the time of the scan, the electrocardiogram obtained before the scan is called a "pre-scan electrocardiogram". The pre-scan electrocardiogram may be obtained at any timing before the start of the scan, but in consideration of avoiding a decrease in the examination efficiency, it is preferable to obtain it at the timing of breathing exercises performed in the conventional examination procedure. In this embodiment, the X-ray exposure period is set in a sufficiently wide range so as to include at least the priority period described later. The cardiac cycle is an example of a "biological motion cycle". In the following, an electrocardiogram-synchronized helical scan in which an X-ray exposure period is set will be described as an example, but the method of determining the priority period in the first embodiment is also applicable to an electrocardiogram-synchronized helical scan in which an X-ray exposure period is not set.

[0028] Returning to the explanation of Fig. 1, the bed device 30 is a device that introduces the subject P, which is to be scanned, into the interior of the rotating frame 17 of the gantry device 10 by having the subject P sit thereon and moving the subject P. The bed device 30 includes, for example, a base 31, a bed driving device 32, a top board 33, and a support frame 34.

[0029] The base 31 includes a housing that supports the support frame 34 so that it can move in the vertical direction (Y-axis direction). The bed driving device 32 includes a motor and an actuator. The bed driving device 32 moves the top board 33, on which the subject P is placed, along the support frame 34 in the longitudinal direction of the top board 33 (Z-axis direction). The top board 33 is a plate-shaped member on which the subject P is placed. The bed driving device 32 moves the top board 33 backward and inserts it into the opening of the gantry 20. The bed driving device 32 moves the top board 33 forward and pulls it out of the gantry 20.

[0030] The bed driving device 32 may move not only the top board 33 but also the support frame 34 in the longitudinal direction of the top board 33. Conversely to the above, the gantry device 10 may be movable in the Z-axis direction, and the rotation frame 17 may be controlled to come to the periphery of the subject P by the movement of the gantry device 10. Alternatively, a configuration in which both the gantry device 10 and the top board 33 are movable may be used.

[0031] The console device 40 has, for example, a memory 41, a display 42, an input interface 43, and a processing circuit 50. In the embodiment, the console device 40 is described as being separate from the gantry device 10, but the gantry device 10 may include some or all of the components of the console device 40. The console device 40 is an example of a "terminal device."

[0032] 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, detection data, projection data, reconstructed image data, CT image data, etc. These data may be stored in an external memory with which the X-ray CT apparatus 1A can communicate, instead of the memory 41 (or in addition to the memory 41). The external memory is controlled by a cloud server that manages the external memory, for example, by the cloud server accepting a read / write request.

[0033] The display 42 displays various kinds of information. For example, the display 42 displays medical images (CT images) generated by a processing circuit, electrocardiograms output by the electrocardiograph 21, GUI (Graphical User Interface) images that accept various operations by operators such as doctors and engineers, and the like. The display 42 is, for example, a liquid crystal display, a CRT (Cathode Ray Tube), an organic EL (Electroluminescence) display, or the like. The display 42 may be provided on the pedestal device 10. The display 42 may be a desktop type, or may be a display device (for example, a tablet terminal) that can wirelessly communicate with the main body of the console device 40.

[0034] The input interface 43 accepts various input operations by an operator and outputs an electrical signal indicating the content of the accepted input operation to the processing circuitry 50. For example, the input interface 43 accepts an input operation for converting the generated CT image data into three-dimensional image data or cross-sectional image data of an arbitrary cross section as an input to an image processing function 54 described later.

[0035] In addition, for example, the input interface 43 accepts input operations of various conditions (scan plans) for generating a CT image of the subject P, such as collection conditions for collecting detection data or projection data, reconstruction conditions for reconstructing a CT image, image processing conditions for generating a post-processed image from the CT image, etc. In addition, for example, the input interface 43 accepts input operations of transfer conditions for transferring detection data to the console device 40.

[0036] For example, the input interface 43 accepts an input operation of phase information as a transfer condition of the detection data. The phase information is information related to the cardiac cycle, for example, information indicating a specific phase in the cardiac cycle of the subject P, or information indicating a section (specific section) before and after the specific phase. The phase information is used to determine priority data from the detection data acquired by ECG-gated helical scanning.

[0037] FIG. 3 is a diagram showing an example of a method for determining priority data based on phase information. The example of an electrocardiogram shown in FIG. 3 is the same as that shown in FIG. 2. In general, in an ECG-gated helical scan, the target phase (reconstruction center) of the reconstruction process is set to about 75% of the RR time (time width between adjacent R-wave peaks), and projection data of a period of about 5% before and after the reconstruction center (i.e., a period of 70% to 80%) is required to generate a CT image of the reconstruction center. The example in FIG. 3 is an example in which the reconstruction center and the acquisition period of priority data (hereinafter referred to as the "priority period") are determined based on this concept.

[0038] In this case, the input interface 43 is configured to accept an operation of inputting a value "75%" indicating the reconstruction center and a value "5%" indicating the width of the priority period as phase information. Note that the reconstruction center and the priority period are determined based on an electrocardiogram acquired during scanning (hereinafter referred to as "scanning electrocardiogram").

[0039] For example, the input interface 43 may be configured to display a scanning electrocardiogram on the display 42 and accept an input operation for specifying a reconstruction center and a priority period for the displayed scanning electrocardiogram. In addition, the time change of an R wave may differ for each cardiac cycle. Therefore, the input interface 43 may be configured to accept an input operation for specifying a reconstruction center and a priority period for each cardiac cycle.

[0040] The input interface 43 is realized by, for example, a mouse, a keyboard, a touch panel, a drag ball, a switch, a button, a joystick, a camera, an infrared sensor, a microphone, etc. The input interface 43 may be realized by a display device (for example, a tablet terminal) capable of wireless communication with the main body of the console device 40.

[0041] In this specification, the input interface 43 is not limited to an interface having physical operation parts such as a mouse and a keyboard. For example, an example of the input interface 43 also includes an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the device and outputs the electrical signal to a control circuit. The input interface 43 is an example of an "input unit."

[0042] Returning to the description of Fig. 1, the processing circuitry 50 controls the overall operation of the X-ray CT apparatus 1A. The processing circuitry 50 includes, for example, a control function 51, a pre-processing function 52, a reconstruction processing function 53, an image processing function 54, a first acquisition function 55A, a determination function 56A, and a second acquisition function 57. The processing circuitry 50 realizes these functions by, for example, a hardware processor executing a program stored in a storage device (storage circuit).

[0043] The hardware processor means a circuit such as a CPU, a GPU, an application specific integrated circuit, a programmable logic device or composite programmable logic device, or a field programmable gate array. Instead of storing a program in a storage device, the program may be directly embedded in the circuit of the hardware processor. The hardware processor is not limited to being configured as a single circuit, and may be configured as a single hardware processor by combining multiple independent circuits to realize each function. The storage device may be a non-transitory (hardware) storage medium. Also, multiple components may be integrated into a single hardware processor to realize each function.

[0044] Each component of the console device 40 or the processing circuit 50 may be distributed and realized by multiple pieces of hardware. The processing circuit 50 may be realized by a processing device capable of communicating with the console device 40, rather than being a component of the console device 40. The processing device is, for example, a workstation connected to one X-ray CT device, or a device (for example, a cloud server) connected to multiple X-ray CT devices and collectively executing processing equivalent to that of the processing circuit 50 described below.

[0045] Each function included in the processing circuitry 50 may be distributed among multiple circuits, or may be made available by starting application software stored in the memory 41. For example, the control function 51, the preprocessing function 52, the reconstruction processing function 53, and the image processing function 54 may be included in the processing circuitry 50, and the first acquisition function 55A, the determination function 56A, and the second acquisition function 57 may be made available by starting application software stored in the memory 41.

[0046] The control function 51 controls various functions of the processing circuit 50 based on the input operation received by the input interface 43. For example, the control function 51 stores the input scan plan in the memory 41, and executes a scan of the subject P according to the scan plan stored in the memory 41. For example, the control function 51 controls the X-ray high voltage device 14, the DAS 16, the control device 18, and the bed driving device 32 to execute collection processing of detection data in the gantry device 10, etc.

[0047] The pre-processing function 52 generates projection data by performing pre-processing (logarithmic conversion processing, offset correction processing, inter-channel sensitivity correction processing, beam hardening correction, etc.) on the detection data output by the DAS 16 in accordance with the scan plan, and stores the generated projection data in the memory 41.

[0048] The reconstruction processing function 53 performs reconstruction processing (such as filtered backprojection or iterative reconstruction) on the projection data generated by the preprocessing function 52 in accordance with the scan plan to generate CT image data, and stores the generated CT image data in the memory 41.

[0049] The image processing function 54 converts the CT image data into three-dimensional image data or cross-sectional image data of an arbitrary cross section by a known method based on an input operation received by the input interface 43. The conversion into three-dimensional image data may be performed by the pre-processing function 52.

[0050] The first acquisition function 55A acquires an electrocardiogram during scanning and stores it in the memory 41.

[0051] The determination function 56A determines priority data from among the detection data acquired by ECG-gated helical scanning based on the scanning ECG. Specifically, the determination function 56A determines, as priority data, the detection data acquired during a priority period determined based on the scanning ECG during the implementation period of the ECG-gated helical scanning. The determination function 56A instructs the second acquisition function 57 to acquire the determined priority data.

[0052] The second acquisition function 57 acquires detection data acquired by performing an ECG-gated helical scan on the subject P from the gantry device 10, and stores the acquired detection data in the memory 41. The detection data acquired by the second acquisition function 57 is used to generate projection data by the pre-processing function 52. Then, the reconstruction processing function 53 performs reconstruction processing using the projection data generated by the pre-processing function 52, thereby generating a CT image.

[0053] 4 is an image diagram showing a method in which the X-ray CT apparatus 1A of the first embodiment transfers priority data from the gantry 10 to the console device 40. As described above, in an ECG-gated helical scan, the gantry 10 irradiates X-rays for each discretely set X-ray exposure period, but during the scan, the DAS 16 outputs a signal indicating that X-rays are not detected even at a timing when X-rays are not irradiated. For this reason, as shown in FIG. 4, the detection data output by the DAS 16 alternately includes detection data indicating detection of X-rays (data in the non-blank portion in the figure, which becomes projection data by preprocessing) and detection data indicating non-detection of X-rays (data in the blank portion in the figure).

[0054] In this case, the determination function 56A recognizes the priority period based on the phase information input by the input interface 43, and determines the detection data acquired during the priority period as the priority data. The determination function 56A instructs the second acquisition function 57 to acquire the determined priority data from the gantry 10. Specifically, the determination function 56A notifies the second acquisition function 57 of the recognized priority period, and the second acquisition function 57 acquires the detection data of the notified priority period from the gantry 10 in the order in which they were acquired.

[0055] The determination function 56A may be configured to acquire all of the priority data from the gantry 10 among all the acquired detection data, and then acquire a part or all of the remaining detection data (hereinafter referred to as "non-priority data") from the gantry 10. For example, in the example of Fig. 4, the non-priority data is detection data other than the priority data among the detection data during the X-ray exposure period, and detection data indicating non-detection of X-rays.

[0056] This allows the console device 40 to shorten the waiting time until the detection data required for the reconstruction process is transferred, and to quickly start the reconstruction process. Specifically, in the past, the reconstruction process was started after waiting for all the detection data to be transferred to the console device 40, but according to the transfer method of this embodiment, the reconstruction process can be started after waiting for the time required for the transfer of the priority data.

[0057] 4, the second acquisition function 57 acquires all of the priority data from the gantry 10 and then acquires some or all of the non-priority data from the gantry 10, but the second acquisition function 57 may be configured to acquire all of the priority data from the gantry 10 and then delete some or all of the non-priority data from the gantry 10. For example, the second acquisition function 57 may instruct the gantry 10 to delete the non-priority data based on an input operation by the user, or may instruct the gantry 10 to delete the non-priority data based on a condition or the like previously set for handling the non-priority data.

[0058] Fig. 5 is a flowchart showing an example of a process flow in which the X-ray CT apparatus 1A determines priority data. The process flow shown in Fig. 5 is started after the scan of the subject P by ECG-gated helical scan is completed, that is, after the gantry device 10 acquires detection data about the subject P. First, the first acquisition function 55A acquires an electrocardiogram during scanning from the electrocardiograph 21 and stores it in the memory 41 (step S101).

[0059] Next, the determination function 56A acquires phase information for determining priority data from the detection data acquired by the gantry device 10 via the input interface 43 (step S102). The determination function 56A stores the acquired phase information in the memory 41. The determination function 56A determines a priority period based on the acquired scanning electrocardiogram and phase information (step S103).

[0060] Next, the second acquisition function 57 acquires the detection data acquired during the priority period determined by the determination function 56A from the gantry 10 as priority data (step S104), and stores the acquired priority data in the memory 41. When the priority data is acquired from the gantry 10, the preprocessing function 52 performs preprocessing on the acquired priority data, and the reconstruction processing function 53 starts reconstruction processing using the priority data after preprocessing. Note that, in this case, the gantry 10 deletes the detection data transferred to the console device 40 from the gantry 10 after the transfer of the detection data is completed.

[0061] Next, the second acquisition function 57 judges whether or not there is any detected data (hereinafter referred to as "data to be acquired") to be acquired by the console device 40 among the detected data other than the priority data (non-priority data) (step S105). For example, the second acquisition function 57 displays on the display 42 a display indicating that it is possible to specify data to be acquired, and accepts input of an operation to specify data to be acquired via the input interface 43. In this case, the second acquisition function 57 judges that "data to be acquired is present" when an operation to specify data to be acquired is input, and judges that "data to be acquired is not present" when an operation to specify data to be acquired is not input. Also, for example, the second acquisition function 57 may judge whether or not there is data to be acquired based on a condition or the like that is preset for data to be acquired.

[0062] If it is determined that "data to be acquired is present" (step S105-YES), the second acquisition function 57 acquires the data to be acquired from the gantry 10 (step S106) and stores the acquired data to be acquired in the memory 41. On the other hand, if it is determined that "data to be acquired is not present" (step S106-NO), the second acquisition function 57 skips step S106 and advances the process to step S107.

[0063] Next, the second acquisition function 57 judges whether or not to delete other detection data (hereinafter referred to as "unacquired data") that has not been acquired from the gantry 10 (step S107). The second acquisition function 57 may judge whether or not to delete the unacquired data based on the user's input operation or a preset condition, as with the data to be acquired. If it is judged that the unacquired data is to be deleted (step S107-YES), the second acquisition function 57 instructs the gantry 10 to delete the unacquired data (step S108). On the other hand, if it is judged that the unacquired data is not to be deleted (step S07-NO), the second acquisition function 57 skips step S108 and ends the processing flow.

[0064] According to the X-ray CT apparatus 1A of the first embodiment configured in this manner, the detection data required for the reconstruction processing can be preferentially transferred from the gantry device 10 to the console device 40, so that the reconstruction processing can be started promptly after the subject P is scanned.

[0065] Second embodiment 6 is a diagram showing an example of the configuration of an X-ray CT apparatus 1B according to the second embodiment. The X-ray CT apparatus 1B is different from the X-ray CT apparatus 1A of the first embodiment in that the processing circuit 50 has a first acquisition function 55B instead of the first acquisition function 55A, and in that the processing circuit 50 has a decision function 56B instead of the decision function 56A. Since the other configurations of the X-ray CT apparatus 1B are similar to those of the X-ray CT apparatus 1A, in FIG. 6, the same reference numerals as those in FIG. 1 are used to designate the same configurations as those of the X-ray CT apparatus 1A, and the description thereof will be omitted.

[0066] The first acquisition function 55B differs from the first acquisition function 55A in that it acquires exposure information indicating the timing of X-ray exposure in an ECG-gated helical scan, instead of an electrocardiogram during scanning of the subject P. The first acquisition function 55B stores the acquired exposure information in the memory 41.

[0067] The decision function 56B differs from the decision function 56A in that it decides priority data based on exposure information instead of a scan-time electrocardiogram. Specifically, the decision function 56B decides, as priority data, detection data acquired during a period (X-ray exposure period) during which detection data indicating X-ray detection was acquired. In other words, the decision function 56B decides that the X-ray exposure period is the priority period. The decision function 56B instructs the second acquisition function 57 to acquire the decided priority data.

[0068] Fig. 7 is a flowchart showing an example of a process flow in which the X-ray CT apparatus 1B determines priority data. Among the processes shown in the flowchart in Fig. 7, the same processes as those in the method for determining priority data in the first embodiment are denoted by the same reference numerals as in Fig. 5, and description thereof will be omitted here. First, the first acquisition function 55B acquires exposure information indicating the timing of X-ray exposure in an ECG-gated helical scan performed on the subject P (step S201).

[0069] Here, it is assumed that the control device 18 of the gantry device 10 records the timing of X-ray exposure as log information when an ECG-gated helical scan is performed. The first acquisition function 55B acquires the log information from the control device 18, extracts the exposure information from the acquired log information, and stores it in the memory 41. Note that, when the above-mentioned log information is stored in the memory 41 as the log information of the control function 51, the first acquisition function 55B may acquire the log information of the control function 51 from the memory 41 and extract the exposure information from the log information of the control function 51.

[0070] Next, the determination function 56B acquires the exposure information from the memory 41, and determines the priority period based on the acquired exposure information (step S202). Specifically, the determination function 56B recognizes the X-ray exposure period in the ECG-gated helical scan based on the exposure information, and determines the recognized X-ray exposure period as the priority period.

[0071] In this case, in step S104, the second acquisition function 57 acquires the detection data acquired during the X-ray exposure period as priority data from the gantry device 10. Fig. 8 is an image diagram showing a method in which the X-ray CT device 1B of the second embodiment transfers priority data from the gantry device 10 to the console device 40. As described above, the X-ray exposure period is set to include at least the priority period in the first embodiment, so that in the second embodiment, the detection data during the X-ray exposure period including the priority data is transferred from the gantry device 10 to the console device 40.

[0072] According to the second embodiment of the X-ray CT apparatus 1B configured in this manner, the detection data during the X-ray exposure period, including the priority data required for the reconstruction processing, can be preferentially transferred from the gantry device 10 to the console device 40, so that the reconstruction processing can be started promptly after the subject P is scanned.

[0073] The detection data transfer method in the second embodiment transfers detection data during the X-ray exposure period with priority. Therefore, the detection data transfer method in the second embodiment has a longer waiting time until the reconstruction process can start than the detection data transfer method in the first embodiment, but since the priority period can be mechanically determined based on the actual X-ray exposure period, the configuration for determining the priority period can be simplified and the waiting time until the reconstruction process can start can be shortened.

[0074] <Modification> In the first embodiment, a case has been described in which priority data is transferred preferentially when detection data is transferred from the gantry 10 to the console device 40, but this transfer method may be applied to data transfer within the gantry 10. As described above, the detection data is first stored in the memory of the DAS 16, transmitted from the memory of the DAS 16 to the receiver 23 via a transmitter (not shown), and transferred by the receiver 23 to the console device 40. Therefore, the transfer method of the first embodiment may be applied to data transfer from the DAS 16 to the receiver 23.

[0075] 9 is an image diagram when the transfer method of the first embodiment is applied to data transfer from the DAS 16 to the receiver 23. In this case, of the detection data stored in the memory of the DAS 16, the priority data is preferentially transferred to the receiver 23. In this case, when the receiver 23 receives a data transfer request from the console device 40, it only has to transfer the detection data received from the DAS 16 to the console device 40 in the order of reception. In this case, the first acquisition function 55A, the determination function 56A, and the second acquisition function 57 related to the determination of the priority period may be provided in the receiver 23 or the DAS 16.

[0076] Similarly, the transfer method of the second embodiment may be applied to data transfer from the DAS16 to the receiver 23. FIG. 10 is an image diagram of the case where the transfer method of the second embodiment is applied to data transfer from the DAS16 to the receiver 23. In this case, of the detection data stored in the memory of the DAS16, the priority data is preferentially transferred to the receiver 23. In this case, when the receiver 23 receives a data transfer request from the console device 40, it only has to transfer the detection data received from the DAS16 to the console device 40 in the order of reception. In this case, the first acquisition function 55B, the determination function 56B, and the second acquisition function 57 related to the determination of the priority period may be provided in the receiver 23 or the DAS16.

[0077] In the first and second embodiments, the transfer method of the detection data has been described, but in cases where the projection data is generated at the transfer source of the detection data or where the detection data is used as it is as the projection data, the transfer method of the embodiment may be used as the transfer method of the projection data. In addition, in the first and second embodiments, the transfer destination device mainly acquires the detection data from the transfer source device, but the transfer method of the embodiment is also applicable to cases where the transfer source device mainly transmits the detection data to the transfer destination.

[0078] Although the embodiment of the X-ray CT apparatus 1A and 1B (hereinafter referred to as "X-ray CT apparatus 1") has been described above, the method of transferring detection data by the X-ray CT apparatus 1 may be applied to other medical image diagnostic apparatuses. Applicable medical image diagnostic apparatuses may be any apparatus that generates medical images by performing reconstruction processing on projection data based on detection data, and may be, for example, a PET (positron emission tomography)-CT apparatus, an MRI (magnetic resonance imaging) apparatus, an angiography imaging apparatus, or the like.

[0079] The detection data transfer method in this embodiment is applicable to an X-ray CT apparatus of a two-stage transfer type that performs a biological information synchronous scan. The biological information synchronous scan may be performed in synchronization with the periodic biological motion of the subject. For example, the biological information synchronous scan may be an electrocardiogram-gated scan performed in synchronization with the subject's heartbeat as described in the above embodiment, or a respiratory-gated scan performed in synchronization with the subject's respiration. For example, the scan method may be a helical scan or a non-helical scan.

[0080] According to at least one of the embodiments described above, the X-ray CT device of the embodiment has a first acquisition unit that acquires the subject's biometric information at the timing when the biometric information synchronous scan is performed, a determination unit that determines priority data from the X-ray detection data acquired in the biometric information synchronous scan based on the biometric information, and a second acquisition unit that acquires the priority data from a storage device that holds the detection data, thereby making it possible to start reconstruction processing more quickly in an X-ray CT device using a two-stage transfer method.

[0081] Although some 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, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0082] 1A, 1B... X-ray CT device, 10... gantry device, 11... X-ray tube, 12... wedge, 13... collimator, 14... X-ray high voltage device, 15... X-ray detector, 16... data acquisition system (DAS: Data Acquisition System), 17... rotating frame, 18... control device, 20... gantry, 21... electrocardiograph, 22... probe, 23... receiver, 30... bed device, 31... base, 32... bed drive device, 33... top plate, 34... support frame, 40... console device, 41... memory, 42... display, 43... input interface, 50... processing circuit, 51... control function, 52... pre-processing function, 53... reconstruction processing function, 54... image processing function, 55A, 55B... first acquisition function, 56A, 56B... decision function, 57... second acquisition function,

Claims

1. 1. An X-ray CT apparatus for acquiring projection data of a subject based on X-ray detection data obtained by a biological information synchronous scan, and generating a CT image of the subject based on the projection data, a first acquisition unit that acquires biological information of the subject at a timing when the biological information synchronous scan is performed; a determination unit that determines, based on the biological information, detection data to be preferentially transferred from among the X-ray detection data acquired in the biological information synchronous scan, as priority data; a first storage device provided on a rotating part that rotatably supports the X-ray tube and the detector, the first storage device storing the detection data; a second acquisition unit that acquires the priority data from the first storage device via a receiving unit that is provided on a fixed unit that supports the rotating unit; An X-ray CT apparatus comprising:

2. the determination unit determines, as the priority data, detection data acquired during a priority period determined based on the biological information during a period during which the detection data was acquired. The X-ray CT apparatus according to claim 1 .

3. An input unit for inputting phase information related to the periodic biological motion of the subject, The determination unit determines the priority period based on the biological information and the phase information. The X-ray CT apparatus according to claim 2.

4. The phase information is information indicating a specific phase in a biological motion cycle of the subject, or information indicating a specific section before and after the specific phase, The determination unit determines the detection data in the specific phase or the detection data in the specific section as the priority data. The X-ray CT apparatus according to claim 3.

5. the determination unit is provided in a terminal device included in the X-ray CT apparatus, the terminal device having a reconstruction processing function for the projection data, the terminal device performs a reconstruction process preferentially on the priority data acquired from the first storage device by the second acquisition unit; The X-ray CT apparatus according to any one of claims 1 to 4.

6. the second acquisition unit acquires all of the priority data from the first storage device among the detection data acquired about the subject, and then acquires a part or all of the remaining detection data from the first storage device; 6. The X-ray CT apparatus according to claim 5.

7. the second acquisition unit acquires all of the priority data from the first storage device, and then deletes a part or all of the remaining detection data based on an input operation by a user.

7. The X-ray CT apparatus according to claim 5 or 6.

8. 1. An X-ray CT apparatus for acquiring projection data of a subject based on X-ray detection data obtained by a biological information synchronous scan, and generating a CT image of the subject based on the projection data, a first acquisition unit that acquires exposure information indicating an X-ray exposure timing in the biological information synchronous scan; a determination unit that determines, based on the exposure information, detection data to be preferentially transferred from among the X-ray detection data acquired in the biological information synchronous scan, as priority data; a first storage device provided on a rotating part that rotatably supports the X-ray tube and the detector, the first storage device storing the detection data; a second acquisition unit that acquires the priority data from the first storage device via a receiving unit that is provided on a fixed unit that supports the rotating unit; An X-ray CT apparatus comprising:

9. an X-ray CT apparatus for acquiring projection data of a subject based on X-ray detection data obtained by a biological information synchronous scan and generating a CT image of the subject based on the projection data, acquiring biological information of the subject at a timing when the biological information synchronous scan is performed; determining, based on the biological information, detection data to be preferentially transferred from among the X-ray detection data acquired in the biological information synchronous scan, as priority data; acquiring the priority data from a first storage device, the first storage device being provided in a rotating section that rotatably supports the X-ray tube and the detector and that stores the detection data, via a receiving section provided in a fixed section that supports the rotating section; A method for controlling an X-ray CT apparatus.

10. an X-ray CT apparatus for acquiring projection data of a subject based on X-ray detection data obtained by a biological information synchronous scan and generating a CT image of the subject based on the projection data, acquiring exposure information indicating an exposure timing of X-rays in the biological information synchronous scan; determining, based on the exposure information, detection data to be preferentially transferred from among the X-ray detection data acquired in the biological information synchronous scan, as priority data; acquiring the priority data from a first storage device, the first storage device being provided in a rotating section that rotatably supports the X-ray tube and the detector and that stores the detection data, via a receiving section provided in a fixed section that supports the rotating section; A method for controlling an X-ray CT apparatus.

11. an X-ray CT apparatus for acquiring projection data of a subject based on X-ray detection data obtained by a biological information synchronous scan and generating a CT image of the subject based on the projection data; acquiring biological information of the subject at a timing when the biological information synchronous scan is performed; determining, based on the biological information, detection data to be preferentially transferred from among the X-ray detection data acquired in the biological information synchronous scan, as priority data; acquiring the priority data from a first storage device, the first storage device being provided in a rotating section that rotatably supports the X-ray tube and the detector and that stores the detection data, via a receiving section provided in a fixed section that supports the rotating section; program.

12. an X-ray CT apparatus for acquiring projection data of a subject based on X-ray detection data obtained by a biological information synchronous scan and generating a CT image of the subject based on the projection data; acquiring exposure information indicating an exposure timing of X-rays in the biological information synchronous scan; determining, based on the exposure information, detection data to be preferentially transferred from among the X-ray detection data acquired in the biological information synchronous scan, as priority data; acquiring the priority data from a first storage device, the first storage device being provided in a rotating section that rotatably supports the X-ray tube and the detector and that stores the detection data, via a receiving section provided in a fixed section that supports the rotating section; program.

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