JP7175639B2 - X-ray imaging device and medical image processing device - Google Patents

Description

An embodiment of the present invention relates to an X-ray imaging apparatus and a medical image processing apparatus.

As a function to protect the X-ray tube, there is an OLP (Over Load Protection) function. According to the OLP function, the amount of heating obtained from the tube voltage, tube current, and scan time and the amount of cooling with the passage of time are calculated before scanning, and the X-ray tube is not used when the heat capacity of the X-ray tube is exceeded. can be managed as

Due to the presence of the OLP function, if you specify a scan condition that exceeds the heat capacity of the X-ray tube based on the current amount of heat, a waiting time is required until the X-ray tube cools down to the amount of heat that can be irradiated with X-rays under that scan condition. Become. Therefore, the X-ray imaging apparatus executes a dialogue with the user regarding the waiting time. For example, a scan condition with waiting time is displayed. It is up to the user to decide whether or not the scan condition with waiting time is permissible. If the user cannot accept scan conditions with waiting time, the tube voltage, tube current, scan time, etc. included in the scan conditions must be changed in order to shorten the waiting time.
However, the relationship between the scanning conditions and the waiting time is difficult to understand, and the user has to change the scanning conditions and confirm the waiting time under the changed scanning conditions until the scanning conditions and the waiting time are acceptable to the user. Need to repeat.

Japanese Patent Application Laid-Open No. 2003-190138 Japanese Patent Application Laid-Open No. 2002-207824

The problem to be solved by the present invention is to improve the workflow and increase the throughput.

An X-ray imaging apparatus according to this embodiment includes an X-ray tube, a detector, an acquisition section, and a display control section. The X-ray tube emits X-rays. The detector detects X-rays emitted from the X-ray tube and transmitted through the subject. The acquisition unit acquires a first scan condition. The display control unit displays first information regarding a first parameter regarding image quality under the first scanning condition and a first waiting time for OLP under the first scanning condition, and displays a first parameter different from the first scanning condition. Second information regarding a second parameter regarding image quality under two scanning conditions and a second waiting time for OLP under the second scanning conditions is displayed in a selectable manner.

FIG. 1 is a block diagram showing the configuration of the X-ray CT apparatus according to the first embodiment. FIG. 2 is a flow chart showing the operation of the X-ray CT apparatus according to the first embodiment. FIG. 3 is a diagram showing a first display example of the correspondence relationship by the display control function according to the first embodiment. FIG. 4 is a diagram showing a second display example of the correspondence relationship by the display control function according to the first embodiment. FIG. 5 is a diagram showing a third display example of the correspondence relationship by the display control function according to the first embodiment. FIG. 6 is a diagram showing a fourth display example of the correspondence relationship by the display control function according to the first embodiment. FIG. 7 is a diagram showing a display example of a reference image according to the first embodiment. FIG. 8 is a list showing an example of scan plans according to the second embodiment. FIG. 9 is a flow chart showing the operation of the X-ray CT apparatus according to the second embodiment. FIG. 10 is a list showing the relationship between image quality and waiting time according to the second embodiment. FIG. 11 is a diagram showing a conceptual display example of scan condition settings when image quality is reduced. FIG. 12 is a block diagram showing a medical image processing apparatus according to this embodiment.

An X-ray imaging apparatus and a medical image processing apparatus according to this embodiment will be described below with reference to the drawings. In the following embodiments, it is assumed that parts denoted by the same reference numerals perform the same operations, and overlapping descriptions will be omitted as appropriate. An embodiment will be described below with reference to the drawings.

(First embodiment)
Hereinafter, the configuration of an X-ray CT (Computed Tomography) apparatus will be described as an example of an X-ray imaging apparatus. FIG. 1 is a block diagram of an X-ray CT apparatus. It should be noted that the X-ray diagnostic apparatus can be used instead of the X-ray CT apparatus.

The X-ray CT apparatus 1 shown in FIG. 1 has a gantry device 10 , a bed device 30 and a console device 40 . For convenience of explanation, FIG. 1 shows that a plurality of gantry devices 10 are drawn. In this embodiment, the rotation axis of the rotating frame 13 in the non-tilt state or the longitudinal direction of the top plate 33 of the bed apparatus 30 is the Z-axis direction, and the axial direction perpendicular to the Z-axis direction and horizontal to the floor surface is are defined as the X-axis direction, the axis direction perpendicular to the Z-axis direction, and the Y-axis direction as the axis direction perpendicular to the floor surface.

For example, the gantry device 10 and the bed device 30 are installed in a CT examination room, and the console device 40 is installed in a control room adjacent to the CT examination room. Note that the console device 40 does not necessarily have to be installed in the control room. For example, the console device 40 may be installed in the same room together with the gantry device 10 and the bed device 30 . In any case, the gantry device 10, the bed device 30, and the console device 40 are connected by wire or wirelessly so as to be able to communicate with each other.

The gantry device 10 is a scanning device having a configuration for X-ray CT imaging of the subject P. As shown in FIG. 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 data acquisition device 18 (DAS (Data Acquisition System) 18).

The X-ray tube 11 is a vacuum tube that generates X-rays by irradiating thermal electrons from a cathode (filament) to an anode (target) by applying a high voltage and supplying a filament current from an X-ray high voltage device 14. is. Specifically, X-rays are generated by thermal electrons colliding with a target. The X-rays generated by the X-ray tube 11 are shaped into a cone beam through, for example, a collimator 17 and irradiated onto the subject P. FIG.

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 X-ray dose to the DAS 18 . The X-ray detector 12 has, for example, a plurality of X-ray detection element arrays in which a plurality of X-ray detection elements are arranged in the channel direction along one circular arc centering on the focal point of the X-ray tube 11 . The X-ray detector 12 has, for example, a row structure in which a plurality of X-ray detection element rows each having a plurality of X-ray detection elements arranged in the channel direction are arranged in the slice direction (row direction).

Specifically, the X-ray detector 12 is, for example, an indirect conversion type detector having a grid, a scintillator array, and a photosensor array. The X-ray detector 12 is an example of a detection section.
The scintillator array has a plurality of scintillators. The scintillator has a scintillator crystal that outputs light with an amount of photons corresponding to the amount of incident X-rays.
The grid has an X-ray shielding plate arranged on the surface of the scintillator array on the X-ray incident side and having a function of absorbing scattered X-rays. Note that the grid may also be called a collimator (one-dimensional collimator or two-dimensional collimator).
The photosensor array has a function of amplifying the light received from the scintillator and converting it into an electric signal, and has photosensors such as photomultiplier tubes (PMTs), for example.
The X-ray detector 12 may be a direct conversion type detector having a semiconductor element that converts incident X-rays into electrical signals.

The rotating frame 13 supports the X-ray generator and the X-ray detector 12 so as to be rotatable around the rotation axis. Specifically, the rotating frame 13 is an annular frame that supports the X-ray tube 11 and the X-ray detector 12 so as to face each other and rotates the X-ray tube 11 and the X-ray detector 12 by means of a control device 15, which will be described later. is. The rotating frame 13 is rotatably supported by a fixed frame (not shown) made of metal such as aluminum. Specifically, the rotating frame 13 is connected to the edges of the stationary frame via bearings. The rotating frame 13 receives power from the drive mechanism of the control device 15 and rotates around the rotation axis Z at a constant angular velocity.

In addition to the X-ray tube 11 and the X-ray detector 12, the rotating frame 13 further includes an X-ray high-voltage device 14 and a DAS 18 to support them. Such a rotating frame 13 is accommodated in a substantially cylindrical housing in which an opening (bore) 19 forming an imaging space is formed. The aperture approximately matches the FOV. The central axis of the opening coincides with the rotational axis Z of the rotating frame 13 . The detection data generated by the DAS 18 is provided in a non-rotating portion (for example, a fixed frame, not shown in FIG. 1) of the gantry device by optical communication from a transmitter having a light emitting diode (LED), It is transmitted to a receiver (not shown) having a photodiode and forwarded to the console device 40 . The method of transmitting the detected data from the rotating frame to the non-rotating portion of the gantry is not limited to the optical communication described above, and any method of non-contact data transmission may be adopted.

The X-ray high voltage device 14 has electric circuits such as a transformer and a rectifier, and has a function of generating a high voltage to be applied to the X-ray tube 11 and a filament current to be supplied to the X-ray tube 11. It has a generating device and an X-ray control device for controlling the output voltage according to the X-rays emitted by the X-ray tube 11 . The high voltage generator may be of a transformer type or an inverter type. Note that the X-ray high-voltage device 14 may be provided on a rotating frame 13 to be described later, or may be provided on a fixed frame (not shown) side of the gantry device 10 .

The control device 15 has a processing circuit having a CPU (Central Processing Unit) and the like, and drive mechanisms such as motors and actuators. The processing circuit has, as hardware resources, a processor such as a CPU or an MPU (Micro Processing Unit) and a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory). In addition, the control device 15 includes an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and other complex programmable logic devices (Complex Programmable Logic Device: CPLD ), which may be implemented by a Simple Programmable Logic Device (SPLD). The control device 15 controls the X-ray high-voltage device 14, the DAS 18, etc. according to commands from the console device 40. FIG. The processor implements the control by reading and implementing the program stored in the memory.

The control device 15 also has a function of receiving an input signal from an input interface 43 (described later) attached to the console device 40 or the gantry device 10 and controlling the operations of the gantry device 10 and the bed device 30 . For example, the control device 15 receives an input signal and performs control to rotate the rotating frame 13 , control to tilt the gantry device 10 , and control to operate the bed device 30 and the tabletop 33 . The control for tilting the gantry device 10 is performed by the control device 15 rotating the frame about an axis parallel to the X-axis direction based on inclination angle (tilt angle) information input by the input interface 43 attached to the gantry device 10 . It is realized by rotating 13. Also, the control device 15 may be provided in the gantry device 10 or may be provided in the console device 40 . Instead of storing the program in the memory, the control device 15 may be configured to directly incorporate the program into the circuit of the processor. In this case, the processor implements the above control by reading and executing the program incorporated in the circuit.

Wedge 16 is a filter for adjusting the dose of X-rays emitted from X-ray tube 11 . Specifically, the wedge 16 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. It is a filter that For example, the wedge 16 (wedge filter, bow-tie filter) is a filter processed from aluminum to have a predetermined target angle and a predetermined thickness.

The collimator 17 is 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. Note that the collimator 17 may also be called an X-ray diaphragm.

The DAS 18 reads electrical signals from the X-ray detector 12 and generates digital data (hereinafter also referred to as raw data) regarding the dose of X-rays detected by the X-ray detector 12 based on the read electrical signals. The raw data is a set of data indicating the channel number and row number of the X-ray detection element from which it was generated, the view number indicating the acquired view (also called projection angle), and the integral value of the detected X-ray dose. be. The DAS 18 is implemented by, for example, an ASIC (Application Specific Integrated Circuit) equipped with circuit elements capable of generating raw data. Raw data is transferred to the console device 40 .

For example, DAS 18 includes a preamplifier, variable amplifier, integrator circuit and A/D converter for each detector pixel. The preamplifier amplifies the electric signal from the X-ray detection element of the connection source with a predetermined gain. A variable amplifier amplifies the electrical signal from the preamplifier with a variable gain. An integrator circuit integrates the electrical signal from the preamplifier over one view period to generate an integrated signal. The crest value of the integral signal corresponds to the X-ray dose value detected by the X-ray detection element of the connection source over one view period. The A/D converter analog-to-digital converts the integration signal from the integration circuit to generate raw data.

The bed device 30 is a device for placing and moving a subject P to be scanned, and includes a base 31 , a bed driving device 32 , a top board 33 and a support frame 34 .
The base 31 is a housing that supports the support frame 34 so as to be vertically movable.
The bed driving device 32 is a motor or actuator that moves the table 33 on which the subject P is placed in the longitudinal direction of the table 33 . The bed driving device 32 moves the tabletop 33 under the control of the console device 40 or the control device 15 . For example, the bed driving device 32 moves the top plate 33 in a direction orthogonal to the subject P so that the body axis of the subject P placed on the top plate 33 coincides with the central axis of the opening of the rotating frame 13 . do. Further, the bed driving device 32 may move the top board 33 along the body axis direction of the subject P according to the X-ray CT imaging performed using the gantry device 10 . The bed drive device 32 generates power by driving at a rotational speed according to the duty ratio of the drive signal from the control device 15 and the like. The bed driving device 32 is realized by a motor such as a direct drive motor or a servo motor, for example.

A top plate 33 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 the longitudinal direction of the top plate 33 in addition to the top plate 33 .

The console device 40 has a memory 41 , a display 42 , an input interface 43 and a processing circuit 44 . Data communication between the memory 41, the display 42, the input interface 43, and the processing circuit 44 is performed via a bus (BUS). Note that the console device 40 is described as being separate from the gantry device 10 , but the console device 40 or a part of each component of the console device 40 may be included in the gantry device 10 .

The memory 41 is a storage device such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or an integrated circuit storage device that stores various information. The memory 41 stores projection data and reconstructed image data, for example. The memory 41 can be connected to portable storage media such as CDs (Compact Discs), DVDs (Digital Versatile Discs), flash memories, semiconductor memory devices such as RAMs (Random Access Memory), etc., in addition to HDDs and SSDs. It may also be a driving device that reads and writes various information with. Also, the storage area of the memory 41 may be in the X-ray CT apparatus 1 or in an external storage device connected via a network. For example, the memory 41 stores data of CT images and display images. The memory 41 also stores a control program according to this embodiment.

The display 42 displays various information. For example, the display 42 outputs a medical image (CT image) generated by the processing circuit 44, a GUI (Graphical User Interface) for accepting various operations from the operator, and the like. For example, the display 42 may be, for example, a liquid crystal display (LCD: Liquid Crystal Display), a CRT (Cathode Ray Tube) display, an organic EL display (OELD: Organic Electro Luminescence Display), a plasma display, or any other arbitrary display. , is enabled. Also, the display 42 may be provided on the gantry device 10 . The display 42 may be of a desktop type, or may be configured by a tablet terminal capable of wireless communication with the main body of the console device 40, or the like.

The input interface 43 receives various input operations from the operator, converts the received input operations into electrical signals, and outputs the electrical signals to the processing circuit 44 . For example, the input interface 43 receives acquisition conditions for acquiring projection data, reconstruction conditions for reconstructing CT images, image processing conditions for generating post-processed images from CT images, and the like from the operator. . As the input interface 43, for example, a mouse, keyboard, trackball, switch, button, joystick, touch pad, touch panel display, etc. can be used as appropriate. In addition, in the present embodiment, the input interface 43 is not limited to physical operation components such as a mouse, keyboard, trackball, switch, button, joystick, touch pad, and touch panel display. For example, the input interface 43 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 the processing circuit 44. . The input interface 43 may be provided on the gantry device 10 . Also, the input interface 43 may be composed of a tablet terminal or the like capable of wireless communication with the main body of the console device 40 .

The processing circuit 44 controls the operation of the entire X-ray CT apparatus 1 according to the electric signal of the input operation output from the input interface 43 . For example, the processing circuit 44 has, as hardware resources, processors such as a CPU, MPU, and GPU (Graphics Processing Unit), and memories such as a ROM and a RAM. The processing circuit 44 executes a system control function 441 , a preprocessing function 442 , a reconstruction processing function 443 , an acquisition function 444 , an OLP calculation function 445 and a display control function 446 by means of a processor that executes programs developed in memory. Each function (system control function 441, preprocessing function 442, reconstruction processing function 443, acquisition function 444, OLP calculation function 445, and display control function 446) is not limited to being realized by a single processing circuit. A processing circuit may be configured by combining a plurality of independent processors, and each function may be realized by each processor executing a program.

The system control function 441 controls each function of the processing circuit 44 based on input operations received from the operator via the input interface 43 . Specifically, the system control function 441 reads the control program stored in the memory 41, develops it on the memory in the processing circuit 44, and controls each part of the X-ray CT apparatus 1 according to the developed control program. . For example, the processing circuit 44 controls each function of the processing circuit 44 based on an input operation received from the operator via the input interface 43 . For example, the system control function 441 acquires a two-dimensional positioning image of the subject P for determining the scan range, imaging conditions, and the like. A positioning image is also called a scanogram or a scout image. The system control function 441 is an example of a system control section.

A preprocessing function 442 generates data by performing preprocessing such as logarithmic conversion processing, offset correction processing, inter-channel sensitivity correction processing, and beam hardening correction on the detection data output from the DAS 18 . Raw data (detection data) before preprocessing and data after preprocessing may be collectively referred to as projection data.

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

The acquisition function 444 acquires the scan conditions set by default or the scan conditions set by the user. Acquisition function 444 is an example of an acquisition unit.

The OLP calculation function 445 calculates the cooling time of the X-ray tube required for executing a scan based on the scan conditions, that is, the waiting time for overload protection (OLP) (hereinafter referred to as OLP waiting time). , determines whether OLP latency occurs.

The display control function 446 controls the display 42 so as to display information on the progress or results of each function or process of the processing circuit 44 . Specifically, the display 42 displays the correspondence between the scan conditions and the OLP waiting time. The display control function 446 is an example of a display control unit.

The processing circuit 44 also performs scan control processing and image processing.
The scan control process is a process of controlling various operations related to X-ray scanning, such as causing the X-ray high-voltage device 14 to supply a high voltage and causing the X-ray tube 11 to emit X-rays.
In the image processing, the CT image data generated by the reconstruction processing function 443 is transformed into tomographic image data or three-dimensional image data of an arbitrary cross section by a known method based on the input operation received from the operator via the input interface 43. This is the process of converting to

The processing circuit 44 is not limited to being included in the console device 40, and may be included in an integrated server that collectively processes detection data acquired by a plurality of medical image diagnostic apparatuses.
Although the console device 40 has been described as executing a plurality of functions with a single console, the plurality of functions may be executed by separate consoles. For example, the functions of the processing circuit 44 such as the preprocessing function 442 and the reconstruction processing function 443 may be distributed.

Next, the operation of the X-ray CT apparatus 1 according to the first embodiment will be described with reference to the flowchart of FIG.
In step S201, scan conditions for the subject are determined. Specifically, by executing the acquisition function 444, the processing circuit 44 acquires subject information (patient information) regarding the ID of the subject P, the inspection target site of the subject P, and the like from a pre-registered examination reservation list. do. Scanning conditions are determined based on the object information.

Scanning condition parameters include, for example, tube current, tube voltage, and scan time. In addition, other information such as focal size may be included as the scan condition. The scan conditions may be determined by the user based on subject information. For scan conditions, a correspondence table between subject information and scan conditions is created and stored in the memory 41 or the like based on past scan cases, and the processing circuit 44 refers to the correspondence table by executing the acquisition function 444, A scan condition corresponding to subject information may be extracted. Scanning conditions may also be determined from subject information by machine learning such as deep learning.

In step S202, the processing circuit 44 determines whether or not an OLP waiting time occurs based on the scan conditions obtained in step S201 by executing the OLP calculation function 445. FIG. By executing the OLP calculation function 445, the processing circuit 44 calculates the OLP waiting time corresponding to the values of the tube voltage, tube current and scan time based on the current heat capacity of the X-ray tube and the limit heat capacity inherent to the X-ray tube. calculate. If the calculation result is zero, it is determined that the OLP waiting time has not occurred, and the process proceeds to step S207. On the other hand, if the calculation result is a numerical value other than zero, it is determined that an OLP waiting time will occur, and the process proceeds to step S203.

Even if the calculation result of the OLP waiting time is a numerical value other than zero and there is an OLP waiting time for calculation, if it is about 5 seconds or 10 seconds, the user may not feel that the OLP waiting time will occur until scanning. is assumed.
Therefore, by executing the OLP calculation function 445, the processing circuit 44 determines that an OLP waiting time has occurred when the OLP waiting time is longer than a predetermined threshold, and when the OLP waiting time is shorter than the threshold, It may be determined that the OLP waiting time does not occur. The predetermined threshold can be set to any time such as 30 seconds or 1 minute.

In step S<b>203 , the processing circuit 44 causes the display 42 to display the correspondence between the scan conditions and the OLP waiting time by executing the display control function 446 . Specifically, by executing the display control function 446, the processing circuit 44 controls the image quality parameters of the scanning conditions (also referred to as first scanning conditions) acquired in step S201 and the OLP waiting time under the first scanning conditions. (also referred to as first waiting time) and information (also referred to as first information) is displayed on the display 42 . Furthermore, by executing the display control function 446, the processing circuit 44 controls parameters related to image quality under other scanning conditions (also referred to as second scanning conditions) different from the first scanning conditions, and the OLP waiting time under the second scanning conditions. (also referred to as second waiting time) and related information (also referred to as second information) are displayed on the display 42 in a selectable manner. The correspondence display format is assumed to be, for example, a graph format such as a distribution map or a function, or a list format such as a table, which will be described later in detail.

In step S204, the processing circuitry 44 determines whether or not the first scan conditions acquired in step S201 have been changed and the second scan conditions have been selected. For example, a user input indicating that processing circuitry 44 has selected one of the second scan conditions displayed on display 42 by executing acquire function 444 (for example, a touch on the display, a mouse for a touch panel display). input, keyboard input, etc.), it is determined that another scan condition has been selected. If another scan condition is selected, the process proceeds to step S205, and if no other scan condition is selected, that is, if there is no change in the scan condition, the process proceeds to step S206. As a method for determining that the scan conditions have not been changed, for example, if the user presses the OK button without selecting the second scan condition, a timeout period is set so that the scan conditions are executed after a certain period of time has elapsed. , if the time-out occurs while the first scan condition is maintained, it may be determined that the scan condition has not been changed.

In step S205, by executing the system control function 441, the processing circuit 44 waits for the execution of scanning for a second waiting time based on the selected second scanning condition. Strictly speaking, the processing circuit 44 should wait for the execution of the scan for a period other than the second waiting time, which is the period from when the correspondence relationship is displayed to when another scan condition is selected by the user. .

In step S206, by executing the system control function 441, the processing circuit 44 waits for the execution of scanning for a first waiting time based on the first scanning condition. Strictly speaking, the processing circuit 44 waits for the execution of the scan for the period from the time when the first waiting time is calculated to the time when it is determined that there is no change in the scanning condition from the first waiting time. good.

After step S205 or step S206 is performed, step S207 is performed. In step S207, for example, by executing the system control function 441, the processing circuit 44 performs scanning according to the parameters of the set scanning conditions. This completes the operation of the X-ray CT apparatus 1 according to the first embodiment.

Next, a first display example of the correspondence relationship by the display control function 446 will be described with reference to FIG.
FIG. 3 is a distribution diagram showing the correspondence between scan conditions and waiting times. The vertical axis is output (tube voltage value, tube current value, or power value), and the horizontal axis is scan time. By executing the display control function 446, the processing circuit 44 generates a distribution map of the scanning conditions and the waiting time with the vertical axis as the output based on the calculated OLP waiting time, and displays it on the display 42 or the like.
In other words, the distribution diagram clearly shows how long the OLP waiting time is required when an image is taken under arbitrary scanning conditions determined by the output and the scanning time.
Also, the current scan conditions acquired by the processing circuit 44 by the acquisition function 444 are marked on the distribution map. Here, the current scan condition 510 (first scan condition) is indicated by an asterisk, but any marker may be used.

In FIG. 3, an area 501 with no OLP waiting time, an area 502 with an OLP waiting time of 1 minute or less, an area 503 with an OLP waiting time of 5 minutes or less, an area 504 with an OLP waiting time of 5 minutes or more, and an output impossible area 505 classified distribution map is shown. In each area, the output and scan time may be classified in finer units. For example, in area 503, 1 minute 10 seconds to 5 minutes may be classified in units of 10 seconds.

Moreover, since the output is too small, there are scanning conditions that cannot be recommended because of poor image quality, although they can be set as scanning conditions. Therefore, by executing the display control function 446, the processing circuit 44 may shade the range 506 of scan conditions that cannot be recommended. Thereby, it is possible to display the scan conditions that are not recommended so as not to be selected.

Next, a second display example of the correspondence relationship by the display control function 446 will be described with reference to FIG.
Similar to FIG. 3, FIG. 4 is a distribution diagram showing the correspondence between scanning conditions and waiting times, but the vertical axis is not output but image quality (SD: Standard Deviation). Since the image quality can be converted from the output and a general method can be used, the description is omitted here. By plotting the image quality on the vertical axis in this manner, it becomes easier for the user to intuitively change the scanning conditions.

Next, a third display example of the correspondence relationship by the display control function 446 will be described with reference to FIG.
FIG. 5 is a graph 520 of a function showing the correspondence between image quality and OLP latency. The vertical axis is the OLP waiting time, and the horizontal axis is the image quality (SD). That is, as compared with FIG. 4, the graph 520 shows only the relationship between image quality and OLP latency, making it easier for the user to understand the relationship between image quality and OLP latency.
For image quality that cannot be recommended, the graph 520 may not be displayed as indicated by an arrow range 506 in FIG.

Next, a fourth display example of the correspondence relationship by the display control function 446 will be described with reference to FIG.
FIG. 6 is a list 600 showing the relationship between image quality and OLP latency. In list 600, image quality (SD) 601 and OLP latency 602 are associated. Specifically, for example, the image quality 601 “−10” and the OLP waiting time 602 “10 minutes” are associated.
Also, in the list 600, the column of the image quality under the current scanning conditions and the corresponding OLP latency is marked (column 603 in FIG. 6). Note that the column 604 related to image quality that cannot be recommended may be displayed in a different color from other columns by adding color or shading.

By referring to the displays of FIGS. 3 to 6, the user can easily understand how much the OLP waiting time can be reduced by reducing the output or image quality, and can select appropriate scanning conditions.
It should be noted that a reference image and a degraded image may be displayed in order to make it possible to compare how much the image quality is visually degraded when the image quality is degraded from that of the image captured under the current scanning conditions.

A display example of the reference image and the degraded image when the image quality is lowered will be described with reference to FIG.
In the example of FIG. 7, a reference image 701 having the image quality assumed to have been captured under the current scanning conditions, and a degraded image 702, which is a reference image whose image quality is lowered according to the image quality after the scanning conditions are changed. displayed in parallel. Note that the reference image 701 and the degraded image 702 are black-and-white reversed images. Any display format may be used as long as the reference image 701 and the degraded image 702 can be compared with each other without being limited to the parallel display.

Regarding the display processing of the reference image and the degraded image, as a specific processing, by executing the display control function 446, the processing circuit 44 displays a sample image and a plurality of images with different image quality (SD) of the sample image. It is prepared in advance and stored in the memory 41, for example. The processing circuit 44 causes the display 42 to display, as a reference image 701, a sample image of image quality (SD) assumed under the current scanning conditions. In addition, the processing circuit 44 acquires a sample image of image quality (SD) corresponding to the changed scanning conditions from the memory 41 and displays it on the display 42 as the degraded image 702 .

According to the first embodiment described above, the X-ray imaging apparatus displays the correspondence relationship between the OLP waiting time based on the output or image quality and the scanning time, or the correspondence relationship between the image quality and the OLP waiting time. is displayed on the corresponding relationship. As a result, the user can easily and intuitively understand how the current scanning conditions can be changed to shorten the OLP waiting time. Also, if the OLP waiting time under the current scan conditions is unacceptable, the user can easily change the scan conditions to appropriate ones.

In addition, since a distribution map, graph, or list is presented to the user so that the correspondence can be understood at a glance, the OLP waiting time is calculated again when the scanning conditions are changed, and the calculated result is The troublesome work of checking each time by the user is eliminated. As a result, workflow can be improved and throughput can be increased.

(Second embodiment)
In the second embodiment, it is assumed that a scan plan including scan conditions for a plurality of scans is created, and whether or not image quality deterioration is permitted is set for each scan condition in the scan plan. This allows the user to adjust the image quality of only scans for which image quality degradation is acceptable, and performs appropriate processing that meets the user's needs.

An example of a scan plan according to the second embodiment will be described with reference to FIG.
FIG. 8 shows an example of a list 800 of scan plans. List 800 includes multiple scan conditions. In the second embodiment, the scan conditions are associated with an identification number 801, tube voltage 802, tube current 803, scan time 804, and setting value 805 (also referred to as setting information) indicating whether or not image quality deterioration is allowed. shall be assumed. The list 800 may be stored in the memory 41, for example, or may be stored in an external storage that can communicate with the console device 40. FIG.

Specifically, for example, as information about scanning, identification number 801 “1”, tube voltage 802 “100 kV”, tube current 803 “300 mA”, scan time 804 “0.5 s”, and setting value 805 “possible” correspond. Attached.
Note that the setting value 805 is not limited to the character string “permissible” or “impossible”, and is a value that can determine whether or not image quality deterioration is permitted, such as a “1” or “0” bit flag. good. The setting value 805 may be set by user input. Also, if there is an example in which deterioration in image quality was allowed under similar scanning conditions in past scans, or an example in which it is empirically known that deterioration in image quality should not be allowed, the setting value 805 is It may be set by default by processing circuitry 44 when generated.

Next, an operation example of the X-ray CT apparatus 1 according to the second embodiment will be described with reference to the flowchart of FIG.
In step S901, a scan plan is determined. In the second embodiment, the scan plan is determined by executing the acquisition function 444 so that the processing circuit 44 acquires setting information for each of a plurality of scan conditions included in the scan plan based on user input. . Note that a scan plan in which setting information is input in advance may be acquired.

In step S902, by executing the OLP calculation function 445, the processing circuit 44 calculates the OLP waiting time when all the scans included in the scan plan are executed without the OLP waiting time between scans based on each scanning condition, Determine whether OLP latency occurs. If the OLP waiting time does not occur, the process proceeds to step S907, and if the OLP waiting time occurs, the process proceeds to step S903.

In step S903, the processing circuit 44 causes the display 42 to display the correspondence relationship between the scan plan and the OLP waiting time by executing the display control function 446. FIG. That is, in the second embodiment, the OLP waiting time that occurs when executing all of the multiple scans included in the scan plan is displayed.

In step S904, the processing circuit 44 determines whether or not the OLP waiting time has been changed. Specifically, for example, by executing the acquisition function 444, the processing circuitry 44 determines that the OLP waiting time has been changed if the user input includes an instruction to reduce image quality. If the OLP waiting time has been changed, the process proceeds to step S905, and if the OLP waiting time has not been changed, the process proceeds to step S906.

In step S905, by executing the system control function 441, the processing circuitry 44 changes the parameters of the scanning conditions only for the scanning conditions for which image quality deterioration is permitted, according to the permitted amount of image quality deterioration.

In step S906, by executing the system control function 441, the processing circuit 44 waits for the scan execution for the OLP waiting time corresponding to the scan plan. That is, if there is no change in the OLP waiting time (step S904: No), the processing circuit 44 may wait for the initial OLP waiting time before executing the scan. Strictly speaking, the processing circuit 44 may wait for the execution of scanning for a period obtained by excluding the period from the time when the first waiting time is calculated to the time when the OLP waiting time is changed from the first waiting time.
On the other hand, if there is a change in the OLP waiting time (step S904: Yes), the processing circuit 44 may wait for the scan execution over the OLP waiting time corresponding to the scan plan after the parameter change. Strictly speaking, the processing circuit 44 may wait for the execution of the scan for a period other than the second waiting time, which is the period from when the correspondence relationship is displayed to when another scanning condition is selected.

If no OLP waiting time occurs in step S902 (step S902: No) or if step S906 has been performed, step S907 is performed.
In step S907, scanning is performed according to the original scan plan, or according to a modified scan plan where image quality degradation is acceptable. This concludes the operation of the X-ray CT apparatus according to the second embodiment.

Next, an example of scan plan control according to the second embodiment will be described with reference to FIGS. 10 and 11. FIG.
FIG. 10 shows a list similar to that of FIG. 6, but in the second embodiment, the image quality (SD) 601 is the image quality for the scan conditions that allowed image quality degradation among the multiple scan conditions included in the scan plan. indicates Also, the OLP wait time 602 indicates the OLP wait time for the scan plan. By executing the display control function 446, the processing circuit 44 causes the display 42 to display a list 600 showing the relationship between the image quality and the OLP waiting time for the scan plan, as shown in FIG.

Here, it is assumed that the user has allowed the image quality (SD) to be lowered and has selected the column 1001 of "image quality (SD) of -20" and OLP waiting time of "5 minutes" as the second scan condition.
In this case, for example, by executing the system control function 441, the processing circuit 44 changes the image quality from the list 800 to "-20" for the scanning conditions of the identification numbers 801 "1" and "3" whose setting value 805 is "allowed". ” set the parameters to lower the

FIG. 11 shows a conceptual display example of scan condition settings when image quality is lowered.
FIG. 11 is a graph showing tube current values as an example of parameters for each scan condition included in the scan plan. By executing the system control function 441, the processing circuit 44 becomes the image quality selected by the user for the scanning conditions for which the setting value 805 is "allowed", that is, the identification numbers 801 "1" and "3" in FIG. control to reduce the value of the tube current. Note that, instead of changing the tube current value, for example, the tube voltage value may be decreased or the scan time may be shortened. In other words, the parameters of the scanning conditions may be adjusted so as to achieve the image quality degradation amount set by the user.

According to the second embodiment described above, the X-ray imaging apparatus presets a scan that allows image quality degradation in the scan plan. As a result, when the image is captured according to the scan plan, it is possible to change the scan conditions only for the scans for which the image quality deterioration is permissible without degrading the image quality for the scans for which the image quality deterioration is not permissible. Therefore, it is possible to perform appropriate processing that meets the user's needs.

(Third Embodiment)
The display control processing according to the above-described embodiments is not limited to being performed in the console device 40 of the X-ray CT apparatus, and may be performed in, for example, a medical image processing apparatus included in a workstation.

A medical image processing apparatus that executes display control processing according to the third embodiment will be described with reference to the block diagram of FIG.
The medical image processing apparatus 1200 includes processing circuitry 1220 , storage circuitry 1240 and communication interface 1260 . Also, signal exchange is performed via the bus 1280 .

Processing circuitry 1220 includes acquisition functionality 1222 , OLP computation functionality 1224 , and display control functionality 1226 . Since the acquisition function 1222, the OLP calculation function 1224, and the display control function 1226 perform the same processing as in the above embodiments, detailed description thereof will be omitted here.
The storage circuit 1240 is, for example, a memory, and stores selected scan conditions, OLP waiting time calculation results (including distribution diagrams, graphs, and lists), reference images, degraded images, and the like.
The communication interface 1260 transmits the scan conditions or scan plan selected for changing the OLP latency to the X-ray imaging apparatus.

According to the third embodiment described above, the medical image processing apparatus executes the display control processing, so that the user can operate the X-ray imaging apparatus and the separate room instead of viewing the console screen of the X-ray imaging apparatus. You can also change the scan conditions or scan plan with .

The X-ray CT apparatus includes a Rotate/Rotate-Type (3rd generation CT) in which the X-ray tube and detector are rotated around the subject P as a unit, and a large number of X-ray detectors arrayed in a ring. There are various types such as Stationary/Rotate-Type (4th generation CT) in which the element is fixed and only the X-ray tube rotates around the subject P, and any type can be applied to this embodiment.

Note that hardware for generating X-rays is not limited to the X-ray tube 11 . For example, in place of the X-ray tube 11, a focus coil for converging the electron beam generated from the electron gun, a deflection coil for electromagnetic deflection, and the deflected electron beam surrounding the half circumference of the subject P collide with each other to emit X-rays. X-rays may be generated using a fifth generation system including a target ring to be generated.

Furthermore, in the present embodiment, both a single-tube type X-ray CT apparatus and a so-called multi-tube type X-ray CT apparatus in which a plurality of pairs of X-ray tubes and detectors are mounted on a rotating ring can be used. Applicable.
In the case of a multi-tube X-ray CT apparatus, the processing circuit 44 creates the above-described correspondence relationship for each tube, and executes the display control processing according to the above-described embodiment based on the longest OLP waiting time. do it.

In addition, each function according to the embodiment can also be realized by installing a program for executing the processing in a computer such as a workstation and deploying them on the memory. At this time, the program that allows the computer to execute the method can be stored and distributed in a storage medium such as a magnetic disk (hard disk, etc.), optical disk (CD-ROM, DVD, etc.), semiconductor memory, etc. .

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

1 X-ray equipment (X-ray CT equipment)
REFERENCE SIGNS LIST 10 gantry device 11 X-ray tube 12 X-ray detector 13 rotating frame 14 X-ray high voltage device 15 controller 16 wedge 17 collimator 18 data acquisition device (DAS)
19 aperture (bore)
30 bed device 31 base 32 bed drive device 33 top board 34 support frame 40 console device 41 memory 42 display 43 input interface 44, 1220 processing circuit 441 system control function 442 preprocessing function 443 reconstruction processing function 444, 1222 acquisition function 445 , 1224 OLP calculation function 446, 1226 Display control function 501 to 505 Area 506 Range 510 Scan condition 520 Graph 600, 800 List 601 Image quality 602 OLP waiting time 603, 604, 1001 Column 701 Reference image 702 Degraded image 801 Identification number 802 Tube voltage 803 tube current 804 scan time 805 set value 1200 medical image processing apparatus 1240 storage circuit 1260 communication interface 1280 bus

Claims (9)

an X-ray tube that emits X-rays;
a detector for detecting X-rays emitted from the X-ray tube and transmitted through a subject;
an acquisition unit that acquires the first scan condition;
displaying first information about a first parameter relating to image quality under the first scanning condition and a first waiting time for OLP under the first scanning condition; and displaying image quality under a second scanning condition different from the first scanning condition. and a second waiting time for the OLP under the second scanning conditions, the second information including parameters relating to image quality that is not recommended, other second information A display control unit that displays in a distinguishable manner from
An X-ray imaging device comprising: 2. The X-ray imaging apparatus according to claim 1, wherein the display control unit displays a distribution diagram showing a correspondence relationship between output and waiting time as the second information, and displays the first information on the distribution diagram. an X-ray tube that emits X-rays;
a detector for detecting X-rays emitted from the X-ray tube and transmitted through a subject;
an acquisition unit that acquires the first scan condition;
displaying first information about a first parameter relating to image quality under the first scanning condition and a first waiting time for OLP under the first scanning condition; and displaying image quality under a second scanning condition different from the first scanning condition. and second information on the second waiting time for OLP under the second scanning conditions are selectably displayed, and the second information is a graph showing the correspondence relationship between the image quality and the waiting time and a display control unit for displaying the first information on the graph;
An X-ray imaging device comprising: 4. The X-ray imaging apparatus according to claim 3, wherein said graph is a distribution map or a function. 2. The X-ray imaging apparatus according to claim 1, wherein the display control unit displays a list showing correspondence between image quality and waiting time, and causes the list to display the first information. The acquisition unit acquires setting information indicating whether or not deterioration in image quality is permissible for each of the plurality of first scan conditions included in the scan plan,
wherein the X-ray imaging apparatus further comprises a system control unit that changes a first parameter of a first scanning condition that allows the deterioration of the image quality based on the setting information when there is an instruction to reduce the image quality. The X-ray imaging apparatus according to any one of Claims 1 to 5. 7. When one of the second information is selected, the display control unit displays a reference image having an image quality based on the second scanning condition included in the selected second information. The X-ray imaging apparatus according to any one of 1. 7. The method according to any one of claims 1 to 6, further comprising a system control unit that executes scanning conditions based on the selected second information when one of the second information is selected. X-ray equipment. an acquisition unit that acquires the first scan condition;
displaying first information about a first parameter relating to image quality under the first scanning condition and a first waiting time for OLP under the first scanning condition; and displaying image quality under a second scanning condition different from the first scanning condition. and a second waiting time for the OLP under the second scanning conditions, the second information including parameters relating to image quality that is not recommended, other second information A display control unit that displays in a distinguishable manner from
A medical image processing apparatus comprising:

Images