Bed movement control device, bed movement control method, program, and medical imaging device

Abstract

To provide a bed movement control device, a bed movement control method, a program, and a medical imaging device, that enable achievement of improved bed movement accuracy.SOLUTION: A bed movement control device acquires information on a distance between sensor measurement target sites in a vertical direction, the information representing a distance between a sensor and a surface facing the sensor at a measurement target site in a subject, acquires, based on the information on the distance between the sensor measurement target sites, first conversion information for converting the number of pixels in a camera image from a center position of the camera image to a measurement start position of the subject into a distance from the center position of the camera image to the measurement start position, and converts, for a position in the vertical direction of the measurement start position of the subject, the number of pixels in the camera image into a distance on a surface orthogonal to the vertical direction.SELECTED DRAWING: Figure 30

Description

[Technical Field]

[0001] The present disclosure relates to a bed movement control device, a bed movement control method, a program, and a medical imaging device. [Background technology]

[0002] Medical imaging devices such as MRI devices are known to have a function that recognizes the position of a subject on a bed and automatically moves the bed to a scanogram acquisition start position. For example, the position of the subject on the bed is recognized by using camera images obtained by capturing images of the subject using cameras installed on the opening of the gantry and on the ceiling of the imaging room. MRI is an abbreviation for Magnetic Resonance Imaging.

[0003] Patent Document 1 describes an X-ray CT device that sets a scan plan based on a scanogram image that is aligned with a camera image obtained by capturing an image of a subject using a video camera. CT is an abbreviation for Computed Tomography.

[0004] Patent Document 2 describes a radiation tomography system that corrects standard radiation irradiation conditions set assuming at least one of a required standard width and a required standard body thickness of a subject, based on at least one of the width and body thickness of the subject detected using an optical sensor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-007255 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-148110 Summary of the Invention [Problem to be solved by the invention]

[0006] However, for example, when the patient is positioned head-first, with the head entering the gantry, and the imaging area is the head, if the bed is moved by applying the bed movement amount calculated based on camera images, etc., the position of the bed in the direction of bed movement will deviate from the original target position.

[0007] Both the device described in Patent Document 1 and the system described in Patent Document 2 have the problem of the bed shifting as described above, but Patent Documents 1 and 2 do not mention anything about the bed shifting as described above.

[0008] The present disclosure has been made in consideration of the above circumstances, and aims to provide a bed movement control device, a bed movement control method, a program, and a medical imaging device that can improve the accuracy of bed movement. [Means for solving the problem]

[0009] A bed movement control device according to a first aspect of the present disclosure includes one or more processors and one or more memories storing a program including one or more instructions to be executed by the one or more processors, and the one or more processors execute the program stored in the one or more memories to use a sensor attached to a measurement room in which the bed is installed to acquire sensor-to-measurement target site distance information representing the distance from the sensor to the surface of the measurement target site of a subject placed on the top of the bed in an up-down direction perpendicular to the installation surface of the bed, and acquires first conversion information based on the sensor-to-measurement target site distance information, which converts the number of pixels in a camera image generated by photographing the subject using a camera attached to the measurement room from the center position of the camera image to the subject's measurement start position into the distance from the center position of the camera image to the measurement start position, and uses the first conversion information to convert the number of pixels in the camera image from the center position of the camera image to the measurement start position, for the position of the subject's measurement start position in the up-down direction, into the distance in a plane perpendicular to the up-down direction from the center position of the camera image to the measurement start position.

[0010] According to the bed movement control device of the first aspect, the number of pixels in the camera image is converted into distance based on the surface of the measurement target part of the subject that faces the sensor. This takes the thickness of the subject into consideration, and improves the accuracy of bed movement compared to when the number of pixels in the camera image is converted into distance based on the tabletop on which the subject rests.

[0011] The term "acquire" is not limited to the manner in which target information is acquired, but may include the manner in which information that serves as a basis for generating target information is acquired, and the target information is generated from the basis information.

[0012] In the bed movement control device of the second aspect, in the bed movement control device of the first aspect, one or more processors may acquire, as the first conversion information, the slope and intercept of a linear function representing the conversion relationship between the number of pixels in the camera image and the distance for each position in the vertical direction.

[0013] According to this aspect, the number of pixels in the camera image is converted into distance using a linear function that represents the conversion relationship between the number of pixels in the camera image and distance for each position in the vertical direction.

[0014] In the bed movement control device of the third aspect, in the bed movement control device of the second aspect, the linear function may be derived using the vertical position at the home position where the tabletop is lowest, home position conversion information representing the conversion relationship between the number of pixels and distance at the home position, and the vertical position at the highest position where the tabletop is highest, and highest position conversion information representing the conversion relationship between the number of pixels and distance at the highest position.

[0015] According to this aspect, the accuracy of the linear function that expresses the conversion relationship between the number of pixels in the camera image and the distance for each position in the vertical direction can be relatively improved.

[0016] A bed movement control device according to a fourth aspect is a bed movement control device according to any one of the first to third aspects, wherein one or more processors may acquire the distance from the center position of the camera image to the measurement start position in the movement direction of the tabletop that is parallel to a plane perpendicular to the up-down direction.

[0017] In this aspect, the movement distance of the tabletop in a plane parallel to the support surface of the bed is calculated.

[0018] A bed movement control device according to a fifth aspect is a bed movement control device according to any one of the first to fourth aspects, wherein one or more processors acquire second conversion information representing the variation in the distance from the sensor to the tabletop for each position relative to the center position of the camera image in the movement direction of the tabletop, and when the sensor is mounted at an angle relative to the installation surface, corrects the acquired distance from the sensor to the tabletop using the variation in the position in the movement direction of the tabletop from which the distance was derived.

[0019] According to this aspect, when the camera is positioned at an angle with respect to the tabletop, the movement distance of the tabletop is calculated taking into account the angle of the camera with respect to the tabletop.

[0020] A bed movement control device according to a sixth aspect is a bed movement control device according to any one of the first to fifth aspects, wherein one or more processors may acquire the movement distance of the tabletop in the direction of movement of the tabletop when moving the subject's measurement start position to a specified position in the measurement device that measures the subject, based on the distance from the center position of the camera image to the subject's measurement start position.

[0021] According to this aspect, improvement in the movement accuracy when moving the top board to a specified position is realized.

[0022] A bed movement control device according to a seventh aspect is the bed movement control device of the sixth aspect, wherein the specified position may be a position where scanogram imaging is started.

[0023] According to this aspect, improvement in the accuracy of movement when the tabletop is moved to the position where scanogram imaging starts is realized.

[0024] A bed movement control method according to an eighth aspect of the present disclosure uses a sensor attached to a measurement room in which the bed is installed to obtain sensor-to-measurement target site distance information representing the distance from the sensor to the surface of the measurement target site of a subject placed on the bed that faces the sensor in an up-down direction perpendicular to the installation surface of the bed, and obtains first conversion information based on the sensor-to-measurement target site distance information, which converts the number of pixels in a camera image generated by photographing the subject using a camera attached to the measurement room from the center position of the camera image to the subject's measurement start position into the distance from the center position of the camera image to the measurement start position, and uses the first conversion information to convert the number of pixels in the camera image from the center position of the camera image to the measurement start position, for the position of the subject's measurement start position in the up-down direction, into the distance in a plane perpendicular to the up-down direction from the center position of the camera image to the measurement start position.

[0025] The bed movement control method according to the eighth aspect of the present disclosure can achieve the same effects as those of the bed movement control device according to the first aspect. The constituent elements of the bed movement control device according to the second to seventh aspects can be applied as constituent elements of the bed movement control method according to the other aspects.

[0026] A program according to a ninth aspect of the present disclosure causes a computer to realize the following functions: using a sensor attached to a measurement room in which a bed is installed, to acquire sensor-to-measurement target site distance information representing the distance from the sensor to the surface of the measurement target site of a subject placed on the bed, in an up-down direction perpendicular to the installation surface of the bed; acquiring first conversion information that converts, based on the sensor-to-measurement target site distance information, the number of pixels in a camera image generated by photographing the subject using a camera attached to the measurement room, from the center position of the camera image to the subject's measurement start position, into the distance from the center position of the camera image to the measurement start position; and using the first conversion information, converting, for the up-down position of the subject's measurement start position, the number of pixels in the camera image from the center position of the camera image to the measurement start position, into the distance in a plane perpendicular to the up-down direction from the center position of the camera image to the measurement start position.

[0027] The program according to the ninth aspect of the present disclosure can provide the same operational effects as the bed movement control device according to the first aspect. The components of the bed movement control device according to the second to seventh aspects can be applied as components of the program according to the other aspects.

[0028] A medical imaging apparatus according to a tenth aspect of the present disclosure includes a measurement device that measures a subject, a measurement data processing device that generates a medical image of the subject based on the measurement results of the subject, a bed equipped with a top plate on which the subject can rest, a sensor attached to a measurement room in which the bed is installed, the sensor acquiring the distance from the sensor to the object to be measured, a camera that captures an image of the subject placed on the top plate and generates a camera image, and a bed movement control device that controls the operation of the bed, the bed movement control device including one or more processors and one or more memories that store a program including one or more instructions to be executed by the one or more processors, the one or more processors executing the program stored in the one or more memories to acquire a medical image of the sensor attached to the measurement room in which the bed is installed. using the above, sensor-to-sensor measurement target site distance information is obtained, which represents the distance from the sensor to the surface of the measurement target site on the subject placed on the bed that faces the sensor, in the vertical direction perpendicular to the installation surface of the bed; and based on the sensor-to-sensor measurement target site distance information, first conversion information is obtained that converts the number of pixels in a camera image generated by photographing the subject using a camera installed in the measurement room from the center position of the camera image to the subject's measurement start position into the distance from the center position of the camera image to the measurement start position, and using the first conversion information, converts the number of pixels in the camera image from the center position of the camera image to the measurement start position, for the vertical position of the subject's measurement start position, into the distance in a plane perpendicular to the vertical direction from the center position of the camera image to the measurement start position.

[0029] The medical imaging device according to the tenth aspect of the present disclosure can achieve the same operational effects as the bed movement control device according to the first aspect. The constituent elements of the bed movement control devices according to the second to seventh aspects can be applied as constituent elements of the medical imaging device according to the other aspects. [Effects of the Invention]

[0030] According to the present disclosure, the number of pixels in the camera image is converted into distance based on the surface of the subject's measurement target area facing the sensor, thereby taking the subject's thickness into consideration and improving the accuracy of bed movement compared to when the number of pixels in the camera image is converted into distance based on the tabletop on which the subject rests. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a perspective view schematically showing the configuration of an MRI apparatus. [Figure 2] FIG. 2 is a functional block diagram showing the electrical configuration of the MRI apparatus shown in FIG. [Figure 3] FIG. 3 is a block diagram showing the hardware configuration of the electrical configuration of the console unit shown in FIG. [Figure 4] FIG. 4 is a functional block diagram showing the electrical configuration of the inspection control device shown in FIG. [Figure 5] FIG. 5 is a flowchart showing the procedure of the vertical movement calibration data generating method. [Figure 6] FIG. 6 is an explanatory diagram of the bed height. [Figure 7] FIG. 7 is a schematic diagram of a screen on which a camera image is displayed. [Figure 8] FIG. 8 is a schematic diagram of another example of the screen on which the camera image is displayed. [Figure 9] FIG. 9 is a schematic diagram showing a specific example of a guide superimposed on a camera image. [Figure 10] FIG. 10 is a graph showing an example of the vertical movement calibration data. [Figure 11] FIG. 11 is an explanatory diagram of the mathematical formula representing the linear function of the graph shown in FIG. [Figure 12] FIG. 12 is a flowchart showing the procedure of the method for generating the longitudinal and lateral movement calibration data. [Figure 13]FIG. 13 is an explanatory diagram of how to obtain the coordinates of both ends of the tabletop. [Figure 14] FIG. 14 is a graph showing an example of the longitudinal and lateral movement calibration data. [Figure 15] FIG. 15 is an explanatory diagram of the mathematical formula representing the linear function of the graph shown in FIG. [Figure 16] FIG. 16 is an explanatory diagram of an example of marking of the center of the camera at the home position. [Figure 17] FIG. 17 is an explanatory diagram of an example of marking the center of the camera at the highest position of the bed. [Figure 18] FIG. 18 is an explanatory diagram for obtaining the amount of deviation of the center position of the tabletop. [Figure 19] FIG. 19 is an explanatory diagram of an example of marking after the top plate is advanced. [Figure 20] FIG. 20 is a diagram illustrating an example of the difference value between the camera center and the ISO center. [Figure 21] FIG. 21 is a schematic diagram showing a specific example of calibration in the lateral and longitudinal directions. [Figure 22] FIG. 22 is a schematic diagram of the distance from the camera to the tabletop when the camera is tilted relative to the installation surface. [Figure 23] FIG. 23 is an explanatory diagram showing an example of measurement positions on the top plate. [Figure 24] FIG. 24 is a schematic diagram of calibration when the camera is tilted with respect to the installation surface. [Figure 25] FIG. 25 is an explanatory diagram of a scanogram imaging start position line when imaging the head. [Figure 26] FIG. 26 is a schematic diagram for explaining the problem of detecting the scanogram imaging start position when measuring the head. [Figure 27] FIG. 27 is a partially enlarged view of FIG. [Figure 28] FIG. 28 is a schematic diagram for explaining the problem of detecting the scanogram imaging start position when measuring the abdomen. [Figure 29]FIG. 29 is an explanatory diagram of the detection of the scanogram imaging start position when measuring the head. [Figure 30] FIG. 30 is a schematic diagram showing how the scanogram imaging start position is detected when measuring the head. [Figure 31] FIG. 31 is an explanatory diagram of the formula used to detect the scanogram imaging start position. DETAILED DESCRIPTION OF THE INVENTION

[0032] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description and accompanying drawings, identical components are designated by the same reference numerals, and duplicate explanations will be omitted. In addition, when multiple components are listed in the following embodiments, it can be interpreted that at least one of the multiple components is included.

[0033] [Example of MRI system configuration] Fig. 1 is a perspective view showing the schematic configuration of an MRI apparatus. The MRI apparatus 10 comprises a measurement device 12 including a gantry 11, a bed 14, and a console unit 16. The measurement device 12 and the bed 14 are located in an imaging room 17A, and the console unit 16 is located in an operation room 17B. Fig. 1 shows a state in which the bed 14 is set at a position where medical images of a subject are taken. The bed 14 is configured to be movable manually or automatically on an installation surface PP.

[0034] The bed 14 includes a tabletop 14A on which a subject undergoing an imaging diagnostic examination can rest. The tabletop 14A can be moved by a bed drive device in the vertical direction, a forward direction to enter the imaging space 11A of the gantry 11, a backward direction to leave the imaging space 11A, and a lateral direction that is perpendicular to the forward direction and perpendicular to the vertical direction. Hereinafter, the forward direction and the backward direction may be collectively referred to as the front-to-rear direction.

[0035] The console unit 16 includes an examination control device 20, an input device 22, and a display device 24. The examination control device 20 controls the control unit in the machine room to control the measuring device 12 and the bed 14, and functions as a control device that executes MRI imaging to acquire NMR signals. The examination control device 20 also functions as a device that processes various types of data, including the process of reconstructing images based on the NMR signals acquired from the measuring device 12 and the communication process via a network, displays the processing results, and stores data.

[0036] The NMR signals obtained from the measuring device 12 are processed and then digitally image processed, and the reconstructed image is displayed on the display device 24 of the console unit 16. Note that NMR is an abbreviation of Nuclear Magnetic Resonance, the English abbreviation of nuclear magnetic resonance.

[0037] A camera unit 26 is installed on the ceiling of the photography room 17A. The camera unit 26 includes a camera and a case 26A that houses the camera. The camera is not shown in Fig. 1. The camera is designated by the reference numeral 27 and is shown in Fig. 2.

[0038] The camera provided in camera unit 26 captures an image of the subject placed on top board 14A and generates a camera image of the subject. The camera provided in camera unit 26 also acquires distance information indicating the distance from the camera to the subject or other object.

[0039] The MRI apparatus 10 described in the embodiment is an example of a medical imaging apparatus, and the examination control device 20 is an example of a measurement data processing device that generates a medical image of a subject based on measurement results of the subject. The imaging room 17A described in the embodiment is an example of a measurement room. The camera unit 26 described in the embodiment is an example of a sensor attached to the measurement room.

[0040] [Electrical configuration of MRI device] Fig. 2 is a functional block diagram showing the electrical configuration of the MRI apparatus shown in Fig. 1. The measurement device 12 includes a static magnetic field coil 32, a gradient magnetic field coil 34, and a gradient magnetic field power supply 36. The static magnetic field coil 32 generates a static magnetic field in a space in which a subject is placed. The gradient magnetic field coil 34 applies a magnetic field gradient to the static magnetic field generated by the static magnetic field coil 32. The gradient magnetic field power supply 36 is a drive power supply for the gradient magnetic field coil 34.

[0041] The measurement device 12 includes a transmitting coil 40, a receiving coil 42, a transmitter 44, and a receiver 46. The transmitting coil 40 generates a high-frequency magnetic field in the measurement region of the subject. The transmitter 44 supplies a pulse current, which is an excitation current, to the transmitting coil 40. The receiving coil 42 receives an NMR signal generated from the subject. The receiver 46 transmits the NMR signal received using the receiving coil 42 to the examination control device 20. The NMR signal may also be referred to as an echo signal.

[0042] The MRI apparatus 10 employs either a vertical magnetic field system or a horizontal magnetic field system depending on the direction of the static magnetic field to be generated. Various configurations are adopted for the static magnetic field coil 32 depending on the magnetic field system. The gradient magnetic field coil 34 includes a plurality of coils that generate gradient magnetic fields in three mutually orthogonal axial directions. Each of the plurality of coils included in the gradient magnetic field coil 34 is driven by a gradient magnetic field power supply 36. Position information is added to the NMR signal generated from the subject due to the application of the gradient magnetic field.

[0043] Although FIG. 2 illustrates an example in which the transmitting coil 40 and the receiving coil 42 are provided separately, there may be an example in which a single coil having the functions of the transmitting coil 40 and the receiving coil 42 is provided.

[0044] The measurement device 12 includes a sequence control device 48. The sequence control device 48 controls the operation of the gradient magnetic field power supply 36 and the transmitter 44 to control the timing of generating the gradient magnetic field and the radio frequency magnetic field. The sequence control device 48 controls the operation of the receiver 46 to control the timing of receiving the NMR signal and executes the measurement. A control time chart applied to the sequence control device 48 is called an imaging sequence, which is set in advance according to the measurement and stored in a storage device or the like provided in the examination control device 20.

[0045] The examination control device 20 controls the operation of each part of the measurement device 12 via the sequence control device 48. The examination control device 20 also functions as a calculation device that performs arithmetic processing on the NMR signals received via the receiver 46 and the sequence control device 48 and acquires image signals of a predetermined imaging region. The examination control device 20 may include the sequence control device 48. The examination control device 20 may be a device that constitutes the MRI device 10, or may be an external device independent of the MRI device 10.

[0046] The inspection control device 20 is electrically connected to an input device 22, a display device 24, and an external storage device 50 so as to be able to communicate with each other. The display device 24 displays the results of arithmetic processing executed using the inspection control device 20. For example, the display device 24 displays a reconstructed image reconstructed based on the NMR signal transmitted from the measurement device 12.

[0047] The display device 24 may be a liquid crystal display, an organic EL display, a projector, or any combination thereof. The organic EL may be referred to as OEL, which is an abbreviation for Organic Electro-Luminescence.

[0048] The input device 22 is an interface through which an operator inputs conditions to be applied to measurement, conditions to be applied to calculation processing, parameters, etc. Examples of the input device 22 include a keyboard and a mouse. The display device 24 and the input device 22 may be integrated using a touch panel display. The operator can use the input device 22 to input parameters such as the number of echoes to be measured, the echo time, and the echo interval.

[0049] The camera 27 provided in the camera unit 26 generates a camera image and distance information based on the depth information of the camera 27, and transmits the camera image and distance information to the inspection control device 20. For example, the camera 27 may include a first camera that generates a camera image and a second camera that acquires distance information.

[0050] The first camera may include an image sensor that converts an optical image of a subject into an electrical signal. Examples of image sensors include a CCD image sensor and a CMOS image sensor. CCD is an abbreviation for Charge Coupled Device, and CMOS is an abbreviation for Complementary Metal Oxide Semiconductor.

[0051] The second camera may be a stereo camera. A passive stereo camera that captures ambient light may be applied to the stereo camera. An active stereo camera that emits infrared light may be applied to the stereo camera. A ToF camera system may be applied to the second camera. ToF is an abbreviation for Time-of-Flight. The first camera described in the embodiment is an example of a camera that generates a camera image, and the second camera is an example of a distance measurement sensor that measures the distance to a measurement object.

[0052] The examination control device 20 detects the position and posture of the subject using the camera image. The examination control device 20 applies the detection result and distance information of the subject to capturing medical images of the subject, such as controlling the movement of the tabletop 14A.

[0053] For example, the camera image and distance information are used to align the height and lateral position of the subject with respect to the ISO center, which is defined as the center of the imaging space 11A of the gantry 11. The ISO center described in the embodiment is an example of the measurement center position of the measurement device that measures the subject.

[0054] The external storage device 50 stores data used in various arithmetic processing executed by the inspection control device 20, data derived as a result of the arithmetic processing, conditions and parameters applied to the arithmetic processing, programs for executing the arithmetic processing, etc. The external storage device 50 may realize a part of the functions of the internal storage device of the inspection control device 20, or the internal storage device of the inspection control device 20 may realize a part of the functions of the external storage device 50.

[0055] The MRI apparatus 10 includes a bed drive device 52. The bed drive device 52 moves the tabletop 14A in the up-down, front-back, and lateral directions. That is, the bed drive device 52 includes a drive mechanism connected to the tabletop 14A and a drive source such as a motor connected to the drive mechanism. The bed drive device 52 is controlled using a bed drive control device. The drive mechanism and drive source are not shown. Also, the bed drive control device is not shown in Figure 2. The components of the bed drive control device are illustrated in Figure 4.

[0056] [Console unit electrical configuration] Fig. 3 is a block diagram showing the hardware configuration of the electrical configuration of the console unit shown in Fig. 1. The inspection control device 20 provided in the console unit 16 is configured using a computer. The computer applied to the inspection control device 20 may be a personal computer, a workstation, or a server computer.

[0057] The processing function of the inspection control device 20 may be realized by a computer system including a plurality of computers. The computer applied to the console unit 16 may be a virtual machine.

[0058] The inspection control device 20 includes a processor 82 , a memory 84 which is a main storage device, a storage 86 which is an auxiliary storage device, an input / output interface 88 , and a bus 90 .

[0059] The processor 82 includes one or more CPUs. The processor 82 may include a GPU. The test control device 20 may further include processors such as a DSP, an ASIC, and a PLD. Note that GPU is an abbreviation for Graphics Processing Unit, DSP is an abbreviation for Digital Signal Processor, ASIC is an abbreviation for Application Specific Integrated Circuit, and PLD is an abbreviation for Programmable Logic Device.

[0060] The processor 82 is connected to the memory 84 , storage 86 , input / output interface 88 , input device 22 , and display device 24 via a bus 90 .

[0061] The memory 84 includes RAM. The memory 84 may include ROM. For example, the storage 86 may include a hard disk drive or a solid state drive. The storage 86 may be a combination of a hard disk drive and a solid state drive. The storage 86 may also include an external storage device such as a removable disk.

[0062] RAM is an abbreviation for Random Access Memory, and ROM is an abbreviation for Read Only Memory. Hard disk drives can be abbreviated as HDD, which stands for Hard Disk Drive. Solid state drives can be abbreviated as SSD, which stands for Solid State Drive.

[0063] The storage device including the memory 84 and the storage 86 stores programs, data, etc. that realize various functions of the MRI apparatus 10. The processor 82 executes the programs stored in the memory 84 to realize various functions of the MRI apparatus 10. The processor 82 comprehensively controls each part of the examination control device 20 and various devices and units provided in the MRI apparatus 10, and performs various processes.

[0064] The input / output interface 88 includes a communication interface connectable to a network, a connection interface connectable to an external device, and the like. For example, a connection interface connectable to an external device, such as a Universal Serial Bus or HDMI (registered trademark), can be applied to the input / output interface 88. The Universal Serial Bus may be referred to as USB, which is an abbreviation for Universal Serial Bus. HDMI is an abbreviation for High-Definition Multimedia Interface.

[0065] The processor 82 communicates with various devices of the MRI apparatus 10 via an input / output interface 88, thereby transmitting and receiving necessary information.

[0066] Various instructions and information input by the operator via the input device 22 are input to the examination control device 20. The operator uses the input device 22 and the display device 24 to interactively operate the MRI apparatus 10.

[0067] The display device 24 displays various information in addition to the examination images captured by the MRI apparatus 10. The display device 24 is used as part of a user interface when receiving input from the input device 22. The display device 24 is not limited to one, and may be in the form of a multi-display having multiple display devices.

[0068] The hardware configuration of the electrical configuration of the console unit 16 shown in FIG. 3 is a variety of control devices provided in the console unit 16, and is applicable to various control devices to which a computer is applied.

[0069] The processor 82 described in the embodiment is an example of one or more processors that execute a program stored in one or more memories. The memory 84 described in the embodiment is an example of one or more memories that store a program containing one or more instructions that are executed by one or more processors.

[0070] [Electrical configuration of inspection control device] Fig. 4 is a functional block diagram showing the electrical configuration of the inspection control device shown in Fig. 2. The inspection control device 20 includes a measurement condition setting unit 100, a measurement control signal generating unit 102, and a measurement control signal output unit 104 as components related to the control of the measuring device 12 shown in Fig. 1. The inspection control device 20 also includes a measurement data acquiring unit 106 and a measurement data processing unit 108 related to the processing of the measurement results of the measuring device 12.

[0071] The measurement condition setting unit 100 sets measurement conditions to be applied to the sequence control device 48 shown in Fig. 2 based on the imaging protocol. Examples of measurement conditions include subject identification information and imaging region.

[0072] The measurement control signal generating unit 102 generates a measurement control signal to be applied to the sequence control device 48 based on the measurement conditions. The measurement control signal output unit 104 transmits the measurement control signal generated using the measurement control signal generating unit 102 to the sequence control device 48. The sequence control device 48 controls the measurement of the subject based on a specified imaging protocol.

[0073] The measurement data acquisition unit 106 acquires NMR signals as measurement data of the subject transmitted from the measurement device 12. The measurement data processing unit 108 generates a reconstructed image of the subject using the acquired NMR signals of the subject.

[0074] The examination control device 20 includes a display signal generating unit 110. The display signal generating unit 110 generates a display signal representing information to be displayed on the display device 24, and transmits the display signal to the display device 24. For example, the display signal generating unit 110 generates a display signal representing a reconstructed image of the subject generated using the measurement data processing unit 108, and transmits the display signal representing the reconstructed image to the display device 24. The reconstructed image of the subject is displayed on the display device 24.

[0075] The examination control device 20 includes a bed driving condition setting unit 120, a bed control signal generating unit 122, a bed control signal output unit 124, and a calibration data generating unit 126 as components related to the movement control of the tabletop 14A.

[0076] The bed driving condition setting unit 120 sets the movement conditions of the table 14A on which the subject rests, based on the imaging protocol. Examples of the movement conditions include the subject's identification information and the subject's body part to be measured.

[0077] The bed control signal generator 122 generates a movement control signal for the table 14A that is applied to the bed driving device 52. The movement control signal for the table 14A defines the vertical movement distance, lateral movement distance, and front-to-back movement distance of the table 14A. The movement speed of the table 14A in each direction is defined appropriately.

[0078] The bed control signal output unit 124 transmits a drive control signal to the bed driving device 52. The bed driving device 52 moves the table top 14A in at least one of the up-down direction, the lateral direction, and the front-rear direction based on the drive control signal.

[0079] The calibration data generation unit 126 generates calibration data for correcting distance information transmitted from the camera 27. The calibration data is applied to correct the distance from the camera 27 to the subject, which is derived using the camera 27. Details of the generation of the calibration data will be described later.

[0080] The inspection control device 20 includes a camera image acquisition unit 130, a camera image processing unit 132, a distance information acquisition unit 134, a distance information processing unit 136, an actual measurement data acquisition unit 138, and an actual measurement data processing unit 140 as components related to the generation of calibration data.

[0081] The camera image acquisition unit 130 acquires a camera image generated using the camera 27 shown in Fig. 2. The camera image may be a through image or a still image taken at any timing.

[0082] The camera image processing unit 132 performs predetermined processing on the camera image. For example, the camera image processing unit 132 performs processing to generate a guide or the like to be superimposed on the camera image.

[0083] The camera image processing unit 132 transmits data representing the camera image, etc. to the display signal generation unit 110. The display signal generation unit 110 generates a display signal representing the camera image, etc., and transmits the display signal to the display device 24. The camera image, etc. is displayed on the display device 24.

[0084] A two-dimensional coordinate system is applied to the camera image, and a position in the camera image is identified using coordinate values. An example of a two-dimensional coordinate system applied to the camera image is a two-dimensional Cartesian coordinate system having two axes that are orthogonal to each other. The origin of the two-dimensional Cartesian coordinate system may be one of the four corners of the camera image.

[0085] Distance information acquisition unit 134 acquires the distance from camera 27 to the subject as distance information transmitted from camera 27.

[0086] Distance information processing unit 136 performs specified processing on the distance information acquired using distance information acquisition unit 134. Distance information processing unit 136 transmits the distance information that has been subjected to specified processing to display signal generation unit 110. Display signal generation unit 110 generates a display signal representing the distance information and transmits the display signal to display device 24. The distance information is displayed on display device 24. An example of the distance information is text information representing the distance from camera 27 to the subject.

[0087] Furthermore, the distance information processing unit 136 transmits the distance information to the calibration data generating unit 126. The distance information is used by the calibration data generating unit 126 to generate calibration data.

[0088] The actual measurement data acquiring unit 138 acquires actual measurement data obtained by an operator. For example, the actual measurement data acquiring unit 138 acquires actual measurement data obtained by an operator using a measuring tool and input by the operator using the input device 22.

[0089] The actual measurement data processing unit 140 performs specified processing on the actual measurement data acquired using the actual measurement data acquisition unit 138. The actual measurement data processing unit 140 transmits the actual measurement data to the calibration data generation unit 126. The actual measurement data is used to generate calibration data in the calibration data generation unit 126. The actual measurement data processing unit 140 may transmit the actual measurement data acquired using the actual measurement data acquisition unit 138 to the display signal generation unit 110, and cause the display device 24 to display the actual measurement data.

[0090] The calibration data generation unit 126, camera image acquisition unit 130, camera image processing unit 132, distance information acquisition unit 134, distance information processing unit 136, actual measurement data acquisition unit 138, and actual measurement data processing unit 140 shown in Figure 4 can function as components of a calibration data generation device that generates calibration data that is applied to correct the movement parameters of the tabletop 14A.

[0091] [Hardware configuration of each processing unit] The hardware structure of the processing unit that executes various processes in the console unit 16 shown in FIG. 2 and the inspection control device 20 shown in FIG. 4 is, for example, various processors as shown below.

[0092] Various types of processors include CPUs, which are general-purpose processors that execute programs and function as various processing units, GPUs, programmable logic devices (PLDs), such as FPGAs (Field Programmable Gate Arrays), which are processors whose circuit configuration can be changed after manufacture, and dedicated electrical circuits, such as ASICs (Application Specific Integrated Circuits), which are processors with circuit configurations designed specifically to execute specific processes.

[0093] A single processing unit may be configured with one of these various processors, or may be configured with two or more processors of the same or different types. For example, a single processing unit may be configured with multiple FPGAs, or a combination of a CPU and an FPGA, or a combination of a CPU and a GPU. Alternatively, multiple processing units may be configured with a single processor. Examples of multiple processing units configured with a single processor include, first, a configuration in which a single processor is configured with a combination of one or more CPUs and software, as typified by client or server computers, and this processor functions as multiple processing units. Second, a configuration in which a processor is used to realize the functions of an entire system including multiple processing units on a single IC (Integrated Circuit) chip, as typified by a system-on-chip (SoC). In this way, the various processing units are configured with one or more of the above-mentioned various processors as a hardware structure.

[0094] Furthermore, the hardware structure of these various processors is, more specifically, an electric circuit made up of a combination of circuit elements such as semiconductor elements.

[0095] [Generating vertical movement calibration data] 5 is a flowchart showing the steps of a method for generating vertical movement calibration data. The vertical movement of the tabletop 14A refers to the movement of the tabletop 14A in a vertical direction perpendicular to the installation surface PP of the bed 14. For example, if the installation surface PP of the bed 14 is parallel to a horizontal plane, the vertical movement refers to the movement of the tabletop 14A in a vertically upward direction and a vertically downward direction. Note that the term "parallel" in this specification is not limited to "strictly parallel" and can include "substantially parallel" that can be considered to be parallel. The term "orthogonal" can also include "substantially orthogonal" as well as "parallel."

[0096] Hereinafter, for convenience of explanation, the horizontal direction may be referred to as the DX direction, the front-to-rear direction as the DY direction, and the up-to-down direction as the DZ direction.

[0097] In generating calibration data, a calibration data generation program is installed in advance in the calibration data generation unit 126, and a computer equipped with a processor that functions as the calibration data generation unit 126 executes the calibration data generation program. Note that the term "program" is synonymous with software.

[0098] In the home position movement step S10, the examination control device 20 shown in FIG. 2 moves the tabletop 14A to the home position relative to the bed 14, which is placed at a position where measurement of the subject is to begin. The home position is the position where the tabletop 14A is lowered to the lowest point, and represents the lowest position of the tabletop 14A. After the home position movement step S10, the process proceeds to the angle of view adjustment step S12. The movement of the bed 14 may be performed manually by an operator or the like, or the bed 14 may be operated automatically or semi-automatically.

[0099] In the angle of view adjustment step S12, the operator visually checks the camera image of the tabletop 14A and confirms the position of the head rest of the tabletop 14A. That is, in the angle of view adjustment step S12, it is confirmed that the head rest is at the top edge of the screen of the display device 24 in the camera image of the tabletop 14A. When confirming the position of the head rest in the camera image, it may be confirmed that the gantry 11 is reflected at the top edge of the camera image.

[0100] If the head rest is not visible within a specified range in the camera image of the bed 14, the mounting direction of the camera unit 26 is adjusted and changed to the specified mounting direction.

[0101] In the angle of view adjustment step S12, the operator visually checks the camera image of the tabletop 14A and checks whether the bed 14 is accommodated within the bed position guide frame displayed on the display screen of the camera image.

[0102] Furthermore, in the angle of view adjustment step S12, the operator visually checks the camera image of the tabletop 14A and checks whether all three marks on the linear guide displayed on the display screen of the camera image are displayed on the tabletop 14A.

[0103] If the position of the bed 14 does not satisfy the above conditions, the position of the bed 14 is adjusted to a position that satisfies the above conditions. Instead of adjusting the bed 14, the mounting position of the camera 27 may be adjusted, or both the adjustment of the bed 14 and the adjustment of the mounting position of the camera 27 may be used.

[0104] If the position of the bed 14 satisfies the above conditions, the examination control device 20 acquires a signal indicating the completion of the angle of view adjustment. The signal indicating the completion of the angle of view adjustment may be sent to the examination control device 20 by the operator operating the input device 22, etc. After the angle of view adjustment step S12, the process proceeds to the home position tabletop height acquisition step S14. The bed position guide frame, guide, and mark are illustrated in FIG. 9.

[0105] In the home position tabletop height acquisition step S14, the home position tabletop height M, which is the height from the installation surface PP of the bed 14 at the home position to the upper surface of the tabletop 14A, is acquired. low The height of the home position tabletop M is obtained. low It is a value actually measured by the operator, and can acquire a value input using the input device 22. After the home position top plate height acquisition step S14, the process proceeds to the home position camera top plate distance acquisition step S16.

[0106] In the home position camera tabletop distance acquisition step S16, the home position camera tabletop distance H low The distance H from the home position camera to the top plate is obtained. low may apply the distance information transmitted from the camera 27. When the value of the distance information transmitted from the camera 27 changes, the home position camera tabletop distance H low The operator can set the approximate median value of the varying values. low The user may input the distance information value to be displayed on the display device 24 using the input device 22 as the distance information.

[0107] The order of the home position top plate height acquisition step S14 and the home position camera top plate distance acquisition step S16 may be reversed, or both steps may be executed in parallel. After the home position camera top plate distance acquisition step S16, the process proceeds to the highest position movement step S18.

[0108] In the highest position movement step S18, the inspection control device 20 raises the top plate 14A from the home position and moves the top plate 14A to the highest position. After the highest position movement step S18, the process proceeds to the highest position top plate height acquisition step S20. The raising of the top plate 14A may be performed manually, automatically, or semi-automatically.

[0109] In the highest position tabletop height acquisition step S20, the highest position tabletop height M, which is the height from the installation surface PP of the bed 14 at the highest position to the upper surface of the tabletop 14A, is acquired. high The highest position tabletop height M is obtained. high is the height of the home position top plate M lowAfter the highest position top plate height acquisition step S20, the process proceeds to the highest position camera top plate distance acquisition step S22.

[0110] In the highest position camera tabletop distance acquisition step S22, the highest position camera tabletop distance H high The highest camera distance from the top plate H is obtained. high is the distance H from the home position camera to the top plate low Similarly, it is derived using the function of the camera 27. After the highest position camera tabletop distance acquisition step S22, the process proceeds to the up / down movement calibration data generation step S24.

[0111] In the up / down movement calibration data generation step S24, the calibration data generation unit 126 calculates the home position tabletop height M low , Home position camera top plate distance H low , Top plate height at highest position M high , and the highest camera top distance H high The vertical movement calibration data is generated using

[0112] After the vertical movement calibration data is generated in the vertical movement calibration data generating step S24, the procedure of the vertical movement calibration data generating method is ended.

[0113] The home position of the tabletop 14A described in the embodiment is an example of the first vertical position, and the highest position of the tabletop 14A is an example of the second vertical position. The top surface of the tabletop 14A at the home position described in the embodiment is an example of a first plane, the top surface of the tabletop 14A at the highest position is an example of a second plane, and the top surface of the tabletop 14A is an example of a placement surface.

[0114] Home position camera top plate distance H described in the embodiment low is an example of the first distance information, and the highest position camera tabletop distance H highis an example of second distance information. The camera image at the home position described in the embodiment is an example of first plane information, and the camera image at the highest position is an example of second plane information. The up-down movement calibration data described in the embodiment is an example of calibration data for correcting movement parameters of the tabletop.

[0115] [Examples of bed height] FIG. 6 is an explanatory diagram of the bed height. The figure schematically shows the home position and highest position of the table 14A at the position of the bed 14 where the table 14A begins to enter the imaging space 11A of the gantry 11. The upper table 14A shown in FIG. 6 shows a state where it is stopped at the highest position. The lower table 14A shown in FIG. 6 shows a state where it is stopped at the home position. Note that the plus DY direction shown in FIG. 6 is the backward direction, and the minus DY direction is the forward direction.

[0116] 6 is installed directly above the center position CP of the tabletop 14A in the home position, with the camera 27 facing straight down and not tilted relative to the horizontal plane. That is, the imaging optical axis OP of the camera 27 passes through the center position CP of the tabletop 14A and faces in a direction perpendicular to the installation surface PP of the bed 14.

[0117] However, in an actual imaging room 17A, it may not be possible to install the camera 27 directly above the center position CP of the tabletop 14A. For example, if a lighting device, a projector, etc. are installed directly above the center position CP of the tabletop 14A, the lighting device, etc. will interfere with the camera 27. In such a case, the camera 27 is installed shifted in at least one of the front-to-back direction and the left-to-right direction.

[0118] [Example of camera image viewed during the angle of view adjustment process] 7 is a schematic diagram of a screen on which a camera image is displayed. The camera image display screen 200 shown in the figure is a display screen for the camera image displayed on the display device 24. The camera image shown in the figure is a through image.

[0119] In the angle of view adjustment step S12 shown in FIG. 5, the operator visually checks the camera image display screen 200 to see whether the gantry 11 and the headrest 14B are displayed on the upper side of the camera image display screen 200.

[0120] 7, the imaging space 11A of the gantry 11 and the headrest 14B are shown on the upper side of the camera image display screen 200, and there is no need to adjust the installation direction of the camera 27 in the angle of view adjustment step S12.

[0121] Fig. 8 is a schematic diagram of another example of a screen on which a camera image is displayed. The camera image displayed on camera image display screen 202 shown in Fig. 8 displays head rest 14C, which has a different shape from head rest 14B shown in Fig. 7. On camera image display screen 202 shown in Fig. 8, imaging space 11A of gantry 11 and head rest 14C are displayed on the upper side of camera image display screen 202, and adjustment of the installation direction of camera 27 is not required in angle of view adjustment step S12.

[0122] [Example of guides superimposed on camera images] Fig. 9 is a schematic diagram showing a specific example of a guide superimposed on a camera image. The camera image display screen 204 shown in Fig. 9 is displayed on the display device 24 in the angle of view adjustment step S12 shown in Fig. 5. The camera image display screen 204 displays a camera image of the table top 14A of the bed 14, and also displays a bed position guide frame EF, a lateral guide XG, and a front-to-back guide YG superimposed on the camera image.

[0123] Furthermore, the camera image display screen 204 displays the first mark Mt, the second mark Mc, and the third mark Mb, which represent the measurement positions of the distance from the camera 27 to the tabletop 14A, superimposed on the front-rear direction guide YG, superimposed on the camera image.

[0124] The bed position guide frame EF represents both lateral ends of the area where the bed 14 is placed. In the angle of view adjustment step S12 shown in Fig. 5, the operator visually checks the camera image display screen 204 to adjust the lateral position of the bed 14 and place the bed 14 between the two bed position guide frames EF. If the camera 27 is shifted left or right, it is sufficient that the bed position guide frame EF and the bed 14 are parallel to each other in the left or right direction.

[0125] The lateral guide XG indicates the center position in the front-to-back direction in the camera image. The front-to-back guide YG indicates the center position in the lateral direction in the camera image. A second mark Mc is displayed at the intersection of the lateral guide XG and the front-to-back guide YG. The second mark Mc indicates the center position of the camera image and indicates the measurement position of the distance from the camera 27 to the center position CP of the tabletop 14A.

[0126] 5, the operator visually checks the camera image to see whether the first mark Mt, the second mark Mc, and the third mark Mb are displayed superimposed on the tabletop 14A. If the first mark Mt, the second mark Mc, and the third mark Mb are not displayed superimposed on the tabletop 14A, the position of the bed 14 or the position of the camera 27 is adjusted, and the bed 14 is placed at a position where the first mark Mt, the second mark Mc, and the third mark Mb are displayed superimposed on the tabletop 14A.

[0127] [Example of vertical movement calibration data] 10 is a graph showing an example of vertical movement calibration data. The horizontal axis of graph G1 shown in the figure represents the distance from the camera 27 to the table top 14A. The vertical axis of graph G1 represents the measured value of the distance from the installation surface PP of the bed 14 to the table top 14A. The unit of the distance from the camera 27 to the table top 14A and the unit of the distance from the installation surface PP of the bed 14 to the table top 14A are millimeters. For convenience, the horizontal axis of graph G1 is referred to as the x-axis, and the vertical axis is referred to as the y-axis. The same applies to graph G2 shown in FIG. 14.

[0128] The linear function F1 expressed as graph G1 is the home position tabletop height M low , Home position camera top plate distance H low , Top plate height at highest position M high , and the highest camera top distance H high The calibration data generation unit 126 shown in Fig. 4 derives, as up-down movement calibration data, a pair of the value of the slope a1 of the linear function F1 and the value of the intercept b1 of the y-axis, which is the value axis.

[0129] Fig. 11 is an explanatory diagram of mathematical expressions representing the linear functions of the graph shown in Fig. 10. The linear function F1 is expressed as Equation 1 shown in Fig. 11. The slope a1 used in Equation 1 is expressed as Equation 2. Furthermore, the y-axis intercept b1 used in Equation 1 is expressed as Equation 3.

[0130] 10 and 11 is used to derive camera_iso_mm, the distance from the camera 27 to the ISO center in the vertical direction. For example, if the distance from the installation surface PP of the bed 14 to the ISO center in the vertical direction is 1234 millimeters, then in the linear function F1, the value of x when y=1234 is the distance camera_iso_mm from the camera 27 to the ISO center in the vertical direction. That is, the linear function F1 is expressed as x=(y-b1) / a1, and camera_iso_mm=(1234-b1) / a1.

[0131] The calibration data is used to derive the vertical movement amount of the tabletop 14A. The distance from the camera 27 to the subject, camera_patient_mm, is obtained using the camera 27. The vertical movement amount of the tabletop 14A, move_height_mm, is calculated by subtracting the distance from the camera 27 to the ISO center, camera_iso_mm, from the distance from the camera 27 to the subject, camera_patient_mm.

[0132] That is, the amount of movement of the tabletop 14A in the up-down direction, move_height_mm, is expressed as (move_height_mm)=(camera_iso_mm)-(camera_point_mm).

[0133] [Example of generating calibration data for longitudinal and lateral movement] Fig. 12 is a flowchart showing the steps of the method for generating front-back and lateral movement calibration data. In the home position movement step S100, the inspection control device 20 shown in Fig. 2 moves the top plate 14A to the home position, similar to the home position movement step S10 shown in Fig. 5. After the home position movement step S100, the process proceeds to the home position top plate end coordinate acquisition step S102.

[0134] In the home position tabletop end coordinate acquisition step S102, the inspection control device 20 acquires the coordinates of both ends of the tabletop 14A in the horizontal direction. Specifically, a two-dimensional Cartesian coordinate system defined in the camera image, based on the DX axis along the horizontal direction and the DY axis along the front-to-back direction, is applied to acquire the coordinate value LowTableLeftPointX of one end of the tabletop 14A in the DX direction and the coordinate value LowTableRightPointX of the other end. The coordinate values ​​are expressed using the number of pixels.

[0135] In the home position top plate end coordinate acquisition step S102, the operator may operate the mouse to click on both ends of the top plate 14A in the DX direction in the camera image as a mouse event, thereby acquiring the coordinate values ​​of both ends of the top plate 14A in the DX direction. After the home position top plate end coordinate acquisition step S102, the process proceeds to the home position top plate center position identification step S104.

[0136] In the step S104 of identifying the center position of the tabletop at the home position, the position of the tabletop 14A that overlaps with the center position of the camera image is marked using the front-rear direction guide YG and the side direction guide XG superimposed on the camera image as markers. After the step S104 of identifying the center position of the tabletop at the home position, the process proceeds to the step S106 of moving to the highest position.

[0137] In the highest position movement step S106, similar to the highest position movement step S18 shown in Fig. 5, the inspection control device 20 raises the top plate 14A from the home position and moves the top plate 14A to the highest position. After the highest position movement step S106, the process proceeds to the highest position top plate end coordinate acquisition step S108.

[0138] In the highest position top plate both end coordinate acquisition step S108, similar to the home position top plate both end coordinate acquisition step S102, the inspection control device 20 acquires the coordinate value HighTableLeftPointX of one end of the top plate 14A in the DX direction at the highest position, and the coordinate value HighTableRightPointX of the other end. After the highest position top plate both end coordinate acquisition step S108, the process proceeds to the highest position top plate center position identification step S110.

[0139] In the top-top center position specifying step S110, similar to the home-position top-top center position specifying step S104, a marking is applied to the position of the top 14A that overlaps with the center position of the camera image using the front-rear direction guide YG and the side direction guide XG superimposed on the camera image as markers. After the top-top center position specifying step S110, the process proceeds to the deviation amount obtaining step S112.

[0140] In the deviation amount acquisition step S112, the operator measures the distance between the marking at the home position and the marking at the highest position in the DX direction and the DY direction.

[0141] That is, in the deviation amount acquisition step S112, a DX deviation amount UpTableZureX representing the deviation amount of the center position of the camera image due to the up and down movement of the tabletop 14A in the DX direction, and a DY deviation amount UpTableZureY representing the deviation amount of the center position of the camera image due to the up and down movement of the tabletop 14A in the DY direction are acquired. After the deviation amount acquisition step S112, the process proceeds to a pre-advance center position identification step S114.

[0142] In the pre-advancement center position specifying step S114, the center position in the DX direction and the center position in the DY direction of the tabletop 14A in the camera image are specified at the pre-advancement position. That is, in the pre-advancement center position specifying step S114, using the lateral direction guide XG and the front-rear direction guide YG superimposed on the camera image as markers, a mark is applied to the center position in the DX direction of the tabletop 14A in the camera image, and a mark is applied to the center position in the DY direction of the tabletop 14A in the camera image. After the pre-advancement center position specifying step S114, the process proceeds to the advancing step S116.

[0143] In the forward movement step S116, the top plate 14A is moved in the forward movement direction until it abuts against the light localizer indicating the ISO center. After the forward movement step S116, the process proceeds to a post-forward movement center position specifying step S118.

[0144] In the post-forward movement center position specifying step S118, similar to the pre-forward movement center position specifying step S114, the center position in the DX direction and the center position in the DY direction of the tabletop 14A in the camera image are specified at the post-forward movement position. After the post-forward movement center position specifying step S118, the process proceeds to the ISO center distance deriving step S120.

[0145] In the ISO center distance derivation process S120, the ISO center distance ISOcenterDistanceX in the DX direction is derived based on the center position in the DX direction of the tabletop 14A identified in the pre-advance center position identification process S114 and the center position in the DX direction of the tabletop 14A identified in the post-advance center position identification process S118.

[0146] Furthermore, in an ISO center distance derivation step S120, the ISO center distance ISOcenterDistanceY in the DY direction is derived based on the center position in the DY direction of the tabletop 14A identified in the pre-advance center position identification step S114 and the center position in the DY direction of the tabletop 14A identified in the post-advance center position identification step S118. After the ISO center distance derivation step S120, the process proceeds to a front-to-back lateral movement calibration data generation step S122.

[0147] In the front-to-back and side-to-side movement calibration data generation process S122, the calibration data generation unit 126 calculates a home position length-pixel conversion value LowTableMpp, which converts the number of pixels at the home position into length, based on the coordinate value LowTableLeftPointX of one end of the DX axis of the tabletop 14A at the home position and the coordinate value LowTableRightPointX of the other end.

[0148] In addition, in the front-to-back and side-to-side movement calibration data generation process S122, the calibration data generation unit 126 uses the coordinate value HighTableLeftPointX of one end of the DX axis of the tabletop 14A at the highest position and the coordinate value HighTableRightPointX of the other end to calculate the highest position length-pixel conversion value HighTableMpp, which converts the number of pixels at the highest position into length.

[0149] Furthermore, in the front-rear and lateral movement calibration data generation step S122, the calibration data generation unit 126 calculates a home position camera tabletop distance H low , and the highest position camera tabletop distance H representing the distance from the camera 27 to the tabletop 14A at the highest position. high is used to generate the longitudinal and lateral movement calibration data.

[0150] After the longitudinal lateral movement calibration data is generated in the longitudinal lateral movement calibration data generation step S122, the procedure of the longitudinal lateral movement calibration data generation method is ended.

[0151] [Example of obtaining the coordinates of both ends of the tabletop] FIG. 13 is an explanatory diagram of how the coordinates of both ends of the tabletop are acquired. A camera image display screen 206 is shown in the figure. The boundary between the tabletop 14A and the side cover 14D, shown using a dashed line, may be used as a guide for the tabletop 14A in the DX direction. The left end of the tabletop 14A in FIG. 13 corresponds to the coordinate values ​​LowTableLeftPointX and HighTableLeftPointX. The right end of the tabletop 14A corresponds to the coordinate values ​​LowTableRightPointX and HighTableRightPointX.

[0152] The overall width of the tabletop 14A in the DX direction is H T Then, the home position length pixel conversion value LowTableMpp is (LowTableMpp)=H T / {(LowTableRightPointX)-(LowTableLeftPointX)}. Note that the coordinate value LowTableRightPointX has a value that exceeds the value of the coordinate value LowTableLeftPointX.

[0153] The highest position length pixel conversion value HighTableMpp is (HighTableMpp)=H T / {(HighTableRightPointX)-(HighTableLeftPointX)}. Note that the coordinate value HighTableRightPointX has a value that exceeds the value of the coordinate value HighTableLeftPointX.

[0154] [Example of longitudinal and lateral movement calibration data] 14 is a graph showing an example of front-to-back lateral movement calibration data. The horizontal axis of graph G2 shown in the figure represents the distance from the camera 27 to the tabletop 14A. The unit of the horizontal axis of graph G2 is millimeters. The vertical axis of graph G2 represents the distance mpp on the tabletop 14A per pixel of the camera image. The unit of the vertical axis of graph G2 is millimeters per pixel.

[0155] The linear function F2 expressed as graph G2 is the distance H from the home position camera to the top plate. low , Highest position camera top plate distance H high , is derived using the home position length-pixel conversion value LowTableMpp and the highest position length-pixel conversion value HighTableMpp. The calibration data generator 126 shown in FIG. 4 derives, as the front-rear and lateral movement calibration data, a pair of the value of the slope a2 of the linear function F2 and the value of the intercept b2 of the y-axis, which is the value axis.

[0156] Fig. 15 is an explanatory diagram of the mathematical formula representing the linear function of the graph shown in Fig. 14. The linear function F2 shown as graph G2 in Fig. 14 is expressed as Equation 4 shown in Fig. 15. The slope a2 used in Equation 4 is expressed as Equation 5. Furthermore, the y-axis intercept b2 used in Equation 4 is expressed as Equation 6.

[0157] The home position length-pixel conversion value LowTableMpp described in the embodiment is an example of home position conversion information that represents the conversion relationship between the number of pixels at the home position and the distance. The maximum position length-pixel conversion value HighTableMpp described in the embodiment is an example of maximum position conversion information that represents the conversion relationship between the number of pixels at the maximum position and the distance.

[0158] [Example of markings at the home position] Fig. 16 is an explanatory diagram of an example of marking the center position at the home position. The camera image display screen 208 shown in Fig. 16 shows the home position DX marking HXM and the home position DY marking HYM that were applied to the tabletop 14A in the home position tabletop center position identification step S104 shown in Fig. 12.

[0159] The home position DX marking HXM is placed along the longitudinal guide YG at a position where it intersects with the lateral guide XG. The home position DY marking HYM is placed along the lateral guide XG at a position where it intersects with the longitudinal guide YG.

[0160] Fig. 17 is an explanatory diagram of an example of marking of the camera center at the highest position. Fig. 17 shows the highest position marking DXM and the highest position marking DYM that were applied to the tabletop 14A in the highest position tabletop center position specifying step S110 shown in Fig. 12.

[0161] The highest position marking DX (MXM) is placed along the longitudinal guide YG at a position where it intersects with the lateral guide XG. The highest position marking DY (MYM) is placed along the lateral guide XG at a position where it intersects with the longitudinal guide YG.

[0162] [Example of obtaining the amount of deviation from the center of the tabletop] Fig. 18 is an explanatory diagram for obtaining the amount of deviation of the tabletop center position. Fig. 18 shows an enlarged view of the home position DX marking HXM, the home position DY marking HYM, the highest position DX marking MXM, and the highest position DY marking MYM shown in Fig. 17.

[0163] 12, the operator measures the distance in the DX direction between the home position DX marking HXM and the highest position DX marking MXM, and derives the DX deviation amount UpTableZureX. The unit of the DX deviation amount UpTableZureX is millimeters.

[0164] When the home position DX marking HXM is located to the right of the highest position DX marking MXM, the DX deviation amount UpTableZureX is a negative value. When the home position DX marking HXM is located to the left of the highest position DX marking MXM, the DX deviation amount UpTableZureX is a positive value.

[0165] Figure 18 illustrates an example in which the distance between each marking is measured using the right edge of each marking as the reference, but the left edge of each marking may be the reference, or the center of each marking may be the reference.

[0166] In the deviation amount acquisition step S112, the operator measures the distance in the DY direction between the home position DY marking HYM and the highest position DY marking MYM, and derives the DY deviation amount UpTableZureY. The unit of the DY deviation amount UpTableZureY is millimeters.

[0167] When the home position DY marking HYM is located above the highest position DY marking MYM, the DY deviation amount UpTableZureY is a negative value. When the home position DY marking HYM is located below the highest position DY marking MYM, the DY deviation amount UpTableZureY is a positive value.

[0168] FIG. 18 illustrates an example in which the distance between each marking is measured using the top of each marking as the reference, but the bottom of each marking may be the reference, or the center of each marking may be the reference.

[0169] [Example of marking in the post-advance center positioning process] 19 is an explanatory diagram of an example of markings after the tabletop has been advanced, showing a frame CIF representing the display range of the camera image, a lateral guide XG superimposed on the camera image, and a front-to-back guide YG.

[0170] In the post-advance center position specifying step S118 shown in FIG. 12, the operator marks the tabletop 14A with a forward position X marking FPXM along the front-rear guide YG and a forward position Y marking FPYM along the lateral guide XG.

[0171] 20 is an explanatory diagram of an example of the difference value between the camera center and the ISO center, which shows the DX difference value ISOcenterDistanceX, which is the difference value between the camera center and the ISO center in the horizontal direction, and the DY difference value ISOcenterDistanceY, which is the difference value between the camera center and the ISO center in the front-to-back direction.

[0172] The light localizer shown in Fig. 20 is a light beam that indicates the ISO center and is used as a mark for aligning the subject with the center of imaging. A laser beam or the like is used as the light localizer.

[0173] The operator measures the DX difference value ISOcenterDistanceX and the DY difference value ISOcenterDistanceY and inputs the measured values ​​to the inspection control device 20. If the camera 27 is attached directly above the position of the ISO center in the lateral direction, the measured value of the DX difference value ISOcenterDistanceX will theoretically be zero. The units of the DX difference value ISOcenterDistanceX and the DY difference value ISOcenterDistanceY are millimeters.

[0174] [Examples of lateral and longitudinal calibration] 21 is a schematic diagram showing a specific example of calibration in the lateral and front-back directions, in which a camera image of a subject placed on the top board 14A of the bed 14 is shown.

[0175] The alignment of the scan start position of the subject using the calibration data with the ISO center is performed according to the following procedure. First, the coordinate values ​​(middle_line, middle_line_st) of the scan start position in the anterior-posterior lateral plane are estimated from the camera image. Here, the origin of the two-dimensional Cartesian coordinate system applied to the camera image is set to the upper left corner of the camera image. The coordinate values ​​are expressed as the number of pixels from the origin.

[0176] Next, the value of the slope a2 of the linear function F2 shown in Fig. 14 and the value of the y-axis intercept b2 are read. The estimated value H_ of the distance from the camera 27 to the tabletop 14A at the height of the tabletop 14A where the scan start position is estimated is estimateis substituted for x in Equation 4 representing the linear function F2 shown in FIG. 15, and the length-pixel conversion value Estimate_TableMpp at the height of the tabletop 14A where the scan start position is estimated is calculated. That is, the length-pixel conversion value Estimate_TableMpp is calculated as follows: (Estimate_TableMpp)=a2×(H_ estimate )+b2.

[0177] Next, the number of pixels from the center position of the camera image to the scan start position is converted into a distance in units such as millimeters using the length-pixel conversion value Estimate_TableMpp. The center position of the camera image is the intersection of the lateral guide XG and the longitudinal guide YG shown in FIG.

[0178] The distance (middle_line_mm) from the center position of the camera image in the horizontal direction to the scan start position is expressed as (middle_line_mm) = {PNX - (middle_line)} × (Estimate_TableMpp). PNX is half the number of pixels in the horizontal direction of the camera image. If the number of pixels in the horizontal direction of the camera image is 600, PNX is 300.

[0179] The distance (middle_line_st_mm) from the center position of the camera image in the front-to-back direction to the scan start position is expressed as (middle_line_st_mm) = {(middle_line_st) - PNY} × Estimate_TableMpp. PNY is half the number of pixels in the front-to-back direction of the camera image. If the number of pixels in the horizontal direction of the camera image is 1200, PNY is 600.

[0180] The distance from the center position of the camera image to the scan start position is a value estimated at the height of the tabletop 14A at which the scan start position is estimated. This value is converted to a value at the highest position of the tabletop 14A.

[0181] First, the distance high_table_middle_line_mm from the center of the camera image in the horizontal direction to the scan start position at the highest position is (high_table_middle_line_mm) = (middle_line_mm) + {(H_ estimate -H high ) / (H low -H high )}×(UpTableZureX).

[0182] In addition, the distance from the center position of the camera image in the front-to-back direction to the scan start position at the highest position is (high_table_middle_line_st_mm) = (middle_line_st_mm) + {(H_ estimate -H high ) / (H low -H high )}×(UpTableZureY). Note that the scan start position described in the embodiment is an example of a measurement start position defined for the subject.

[0183] Next, the movement distance of the table top 14A in the lateral direction, move_shift_mm, and the movement distance of the table top 14A in the front-to-rear direction, move_position_mm, are calculated. The movement distance of the table top 14A in the lateral direction, move_shift_mm, is expressed as (move_shift_mm)=(ISOcenterDistanceX)-(high_table_middle_line_mm).

[0184] The movement distance move_position_mm of the tabletop 14A in the front-rear direction is expressed as (move_position_mm)=(ISOcenterDistanceY)-(high_table_middle_line_st_mm).

[0185] When the value of the movement distance move_shift_mm of the top board 14A in the lateral direction is negative, the top board 14A is moved to the right in Fig. 21. On the other hand, when the value of the movement distance move_shift_mm is positive, the top board 14A is moved to the left in Fig. 21.

[0186] The movement distance move_position_mm of the tabletop 14A in the front-rear direction is always negative, and the tabletop 14A is moved forward.

[0187] [Example of calibration when the camera is installed at an angle] 22 is a schematic diagram of the distance from the camera to the tabletop when the camera is tilted relative to the installation surface. In some cases, the camera 27 is tilted relative to the installation surface PP so that the tabletop 14A fits within the frame of the camera image. For example, the imaging optical axis OP of the camera 27 is rotated about a rotation axis parallel to the horizontal direction, and the tilt of the camera 27 is adjusted within a range of, for example, plus 5 degrees to minus 5 degrees.

[0188] When the camera 27 is tilted and adjusted, the distance from the camera 27 to the tabletop 14A varies depending on the position in the front-to-back direction on the tabletop 14A. Therefore, when adjusting the mounting position in the front-to-back and lateral directions, the distance from the camera 27 to the tabletop 14A for each position in the front-to-back direction on the tabletop 14A is taken into account.

[0189] That is, the distance from camera 27 to tabletop 14A affects the accuracy of calculating the movement distance of tabletop 14A in the front-to-rear direction. Therefore, it is necessary to adjust the installation direction of camera 27 taking into account the inclination of camera 27 with respect to installation surface PP.

[0190] When the orientation of camera 27 is adjusted so that the photographing optical axis OP of camera 27 is perpendicular to the installation surface PP, the distance from camera 27 to the center position of the camera image captured in the camera image is measured as the distance from camera 27 to tabletop 14A. That is, the linear function F1 shown in Fig. 10 and the linear function F2 shown in Fig. 14 are based on the center position of the camera image.

[0191] When the orientation of camera 27 relative to installation surface PP is adjusted by tilting within a specified range, the distance from camera 27 to tabletop 14A measured at a position different from the center position of the camera image is converted to a value at the center position of the camera image. A linear function used for this conversion is prepared.

[0192] 23 is an explanatory diagram showing an example of measurement positions on the tabletop. The first mark Mt, second mark Mc, and third mark Mb shown in FIG.

[0193] At the home position of the bed 14, the distance from the camera 27 to the second mark Mc is defined as D_center, the distance from the camera 27 to the first mark Mt is defined as D_minus, and the distance from the camera 27 to the third mark Mb is defined as D_plus. Each of the above distances is acquired as distance information of the camera 27. The unit of each distance is millimeters.

[0194] The linear function F3 on the negative side in the front-to-back direction is expressed as z = a3 × y. In the formula expressing the linear function F3, z and y represent values ​​in the up-down direction and the front-to-back direction, respectively. The same applies to the linear function F4 below.

[0195] When the number of pixels representing the distance from the second mark Mc to the first mark Mt in the forward / backward direction is set to minus 500 pixels, the slope a3 of the linear function F3 is expressed as a3 = {(D_center) - (D_minus)} / {0 - (-500)} = {(D_center) - (D_minus)} / 500.

[0196] Similarly, the positive linear function F4 in the front-to-back direction is expressed as z = a4 × y. When the number of pixels representing the distance from the second mark Mc to the third mark Mb in the front-to-back direction is plus 500 pixels, the slope a4 of the linear function F4 is expressed as a4 = {(D_center) - (D_plus)} / {0 - (+500)} = {(D_center) - (D_plus)} / (-500). Here, the 0 in the equations representing the slope a3 of the linear function F3 and the slope a4 of the linear function F4 represents the coordinate value of the center position of the camera image.

[0197] That is, the number of pixels from the second mark Mc to the first mark Mt and the number of pixels from the second mark Mc to the third mark Mb indicate that the second mark Mc is used as a reference. The slope a3 of the linear function F3 and the slope a4 of the linear function F4 are stored as calibration data.

[0198] 24 is a schematic diagram of calibration when the camera is tilted with respect to the installation surface PP. When the camera is installed tilted with respect to the installation surface PP, the estimated value HN_ of the distance from the camera 27 to the tabletop 14A is estimate or an estimated value HP_ of the distance from the camera 27 to the top plate 14A. estimate A correction value for is calculated.

[0199] In calculating the correction value, the estimated value HN_ of the distance from the camera 27 to the tabletop 14A at the estimated position MPN on the tabletop 14A is estimate When the MPN is estimated, the coordinate value Y in the forward / backward direction of the estimated position MPN is estimate The estimated position MPN is a position on the negative side in the front-to-back direction with respect to the center position of the camera image. Here, the center position of the camera image coincides with the center position of the camera image when the camera 27 is not tilted.

[0200] Y coordinate value in the forward / backward direction of the estimated position MPN estimate If is a negative value, the coordinate value Y is estimate is substituted, and the correction value ZCN is calculated as the value of z of the linear function F3.

[0201] The estimated value H_ of the distance from the camera 27 to the tabletop 14A at the center position of the camera image estimate is the estimated value HN_ of the distance from the camera 27 to the tabletop 14A at the estimated position MPN. estimate , and the correction value ZCN, (H_ estimate )=(HN_ estimate )-(ZCN).

[0202] Similarly, at the estimated position MPP on the positive side in the front-to-rear direction, the estimated value HP_ of the distance from the camera 27 to the tabletop 14A is estimate is estimated, and the coordinate value Y in the forward / backward direction of the estimated position MPP is estimate If is a positive value, the coordinate value Y is estimate is substituted, and the correction value ZCP is calculated as the value of z of the linear function F4.

[0203] The estimated value H_ of the distance from the camera 27 to the tabletop 14A at the center position of the camera image estimate is the estimated value HP_ of the distance from the camera 27 to the tabletop 14A at the estimated position MPP. estimate , and the correction value ZCP, (H_ estimate )=(HP_ estimate )+(ZCP).

[0204] When the camera 27 is tilted with respect to the installation surface PP, the estimated value of the distance from the camera 27 to the tabletop 14A at an estimated position away from the center position of the camera image is smaller than the estimated value H_ of the distance from the camera 27 to the tabletop 14A at the center position of the camera image. estimate and the estimated value H_ estimate The longitudinal and lateral calibrations are performed using

[0205] The correction values ​​ZCN and ZCP described in the embodiment are examples of the amount of variation in the distance from the sensor to the tabletop. The linear functions F3 and F4 described in the embodiment are examples of second conversion information.

[0206] [Effects of the embodiment] The inspection control device 20 according to the embodiment can achieve the following advantageous effects.

[0207] [1] The camera 27 installed on the ceiling of the imaging room 17A is adjusted to a position and posture such that the entire top board 14A is captured in the camera image and the head rest 14B and the like are captured in specified positions in the camera image.

[0208] At the home position of the tabletop 14A of the bed 14, a camera 27 installed on the ceiling of the radiography room 17A is used to measure the distance from the camera 27 to the tabletop 14A of the bed 14, which is the home position camera tabletop distance H low is measured, and the height M of the home position tabletop, which is the height from the installation surface PP of the bed 14 to the upper surface of the tabletop 14A, is low is measured by the operator.

[0209] When the tabletop 14A is at the highest position, the distance from the camera 27 to the tabletop 14A of the bed 14 is defined as the highest position camera tabletop distance H high is measured, and the height M of the tabletop at the highest position is the height from the installation surface PP of the bed 14 to the upper surface of the tabletop 14A. high is measured by the operator.

[0210] From the measurement results, a linear function F1 is derived that expresses the relationship between the distance from the installation surface PP to the tabletop 14A and the distance from the camera 27 to the tabletop 14A. The combination of the slope a1 of the linear function F1 and the y-axis intercept b1 is derived and stored as up-down direction calibration data.

[0211] This makes it possible to correct the vertical movement distance of the tabletop 14A based on the measurement results of the distance from the camera 27 to the subject, even if the position at which the camera 27 is installed is shifted from the predetermined position.

[0212] [2] At the home position of the tabletop 14A, the number of pixels corresponding to the entire horizontal length of the tabletop 14A is derived from the coordinate values ​​of both ends of the tabletop 14A in the horizontal direction captured in the camera image. The entire horizontal length of the tabletop 14A is divided by the derived number of pixels to calculate the home position length-pixel conversion value LowTableMpp.

[0213] When the tabletop 14A is at its highest position, the number of pixels corresponding to the entire horizontal length of the tabletop 14A is derived from the coordinate values ​​of both ends of the tabletop 14A in the horizontal direction captured in the camera image. The entire horizontal length of the tabletop 14A is divided by the derived number of pixels to calculate the home position length-pixel conversion value HighTableMpp.

[0214] From the measurement results, a linear function F2 is derived that expresses the relationship between the length-pixel value conversion value and the distance from the camera 27 to the tabletop 14A. A set of the slope a2 of the linear function F2 and the intercept b2 of the y-axis, which is the value axis, is derived and stored as the front-rear and lateral direction calibration data.

[0215] As a result, at any height of the tabletop 14A, the number of pixels from the estimated center position of the camera image to the scan start position in the camera image is converted into a distance in units such as millimeters.

[0216] [3] In the horizontal direction, the amount of deviation UpTableZureX between the center position of the camera image when the tabletop 14A is at the home position and the center position of the camera image when the tabletop 14A is at the highest position is measured.

[0217] As a result, in the horizontal direction, using the offset amount UpTableZureX, the distance middle_line_mm from the center position of the camera image at any height of the tabletop 14A to the scan start position is converted to high_table_middle_line_mm, which is the distance from the center position of the camera image at the highest position of the tabletop 14A to the scan start position.

[0218] Additionally, the amount of deviation UpTableZureY in the front-to-rear direction between the center position of the camera image at the home position of the tabletop 14A and the center position of the camera image at the highest position of the tabletop 14A is measured.

[0219] As a result, in the front-to-back direction, using the offset amount UpTableZureY, the distance middle_line_st_mm from the center position of the camera image at any height of the tabletop 14A to the scan start position is converted to high_table_middle_line_st_mm, which is the distance from the center position of the camera image at the highest position of the tabletop 14A to the scan start position.

[0220] [4] At the highest position of the tabletop 14A, the distance ISOcenterDistanceX between the lateral center of the camera image and the ISO center is measured.

[0221] As a result, the movement distance move_shift_mm of the table top 14A in the horizontal direction is calculated from the distance high_table_middle_line_mm from the center position of the camera image to the scan start position.

[0222] Similarly, at the highest position of the tabletop 14A, the distance ISOcenterDistanceY between the center of the camera image in the front-to-rear direction and the ISO center is measured.

[0223] As a result, the movement distance move_position_mm of the table top 14A in the front-to-rear direction is calculated from the distance high_table_middle_line_st_mm from the center position of the camera image to the scan start position.

[0224] [5] A negative measurement position is defined for the negative side in the front-to-rear direction, a specified number of pixels away from the center position of the camera image. A slope a3 of a linear function F3 for the negative side in the front-to-rear direction is defined using the distance D_center from the camera 27 to the center position of the camera image, the distance D_minus from the camera 27 to the negative measurement position, and the number of pixels from the center position of the camera image to the negative measurement position.

[0225] This allows the distance traveled in the forward / backward direction of the tabletop 14A to be corrected based on the distance from the camera 27 to the tabletop 14A at the center position of the camera image, even if the camera 27 is tilted to the negative side in the forward / backward direction relative to the installation surface PP.

[0226] A positive-side measurement position is defined on the positive side in the front-to-back direction, a specified number of pixels away from the center position of the camera image. A slope a4 of a linear function F4 on the positive side in the front-to-back direction is defined using the distance D_center from the camera 27 to the center position of the camera image, the distance D_plus from the camera 27 to the positive-side measurement position, and the number of pixels from the center position of the camera image to the negative-side measurement position.

[0227] This allows the distance traveled in the forward / backward direction of the tabletop 14A to be corrected based on the distance from the camera 27 to the tabletop 14A at the center position of the camera image, even if the camera 27 is tilted to the positive side in the forward / backward direction relative to the installation surface PP.

[0228] [Another embodiment of calculating the bed movement amount] 25 is an explanatory diagram of the scanogram imaging start position line when imaging the head. The figure shows a camera image of the bed 14 on which the subject is placed. The CIF shown in the figure represents the frame of the camera image. The scanogram imaging start position is synonymous with the scan start position shown in FIG.

[0229] When measuring the subject's head, the scanogram imaging start position line SSL is set to a position away from the subject's parietal region Par in the IN direction. The IN direction is the direction in which the bed 14 moves toward the inside of the gantry, and corresponds to the upward direction in the camera image.

[0230] When the light localizer irradiation is performed after the top plate 14A of the bed 14 is automatically adjusted based on the camera image, the laser light of the light localizer is irradiated at a position shifted in the IN direction from the top of the head Par, relative to the center position of the gantry, which is directly below the tube where it should be irradiated.

[0231] That is, in the automatic adjustment of the top plate 14A of the bed 14 based on the camera image, it is desired that the top plate 14A of the bed 14 be moved to a position where the light localizer is irradiated onto the vertex Par of the subject's head.

[0232] Fig. 26 is a schematic diagram illustrating the problem of detecting the start position of a scanogram when measuring the head. Fig. 27 is a partially enlarged view of Fig. 26. Figs. 26 and 27 schematically illustrate how a subject placed on the top board 14A of the bed 14 is photographed using a camera 27.

[0233] When the measurement target part is the head, the scanogram imaging start position is set not directly below or near directly below the camera 27, but at a position away from directly below the camera 27 in the front-to-back direction. When viewed from the camera 27, the subject's head is in a position looking down at an angle, and the scanogram imaging start position line SSL in the camera image appears to be at the position of the top of the head Par.

[0234] On the other hand, the amount of movement of the tabletop 14A is calculated using the pixel position on the tabletop 14A in the camera image as a target. That is, the position Pb on the tabletop 14A in the camera image is used to calculate the amount of movement of the tabletop 14A.

[0235] Then, when the tabletop 14A is actually moved based on the calculation result of the movement amount of the tabletop 14A and the light localizer is irradiated, the light localizer is irradiated at the position Pb or in the vicinity of the position Pb.

[0236] Although the calculation of the movement amount of the tabletop 14A to move the tabletop 14A to the position Pb is performed correctly, the position Pb deviates from the scanogram imaging start position line SSL on the camera image.

[0237] Therefore, the distance La in the anterior-posterior direction from position Paa on the tabletop 14A, which is directly below the scanogram imaging start position line SSL in the camera image shown in Figure 27, to position Pb on the tabletop 14A is taken into consideration, and the amount of movement of the tabletop 14A based on the camera image is calculated.

[0238] 28 is a schematic diagram illustrating the problem of detecting the scanogram capture start position when measuring the abdomen. The angle of view from camera 27 of the subject's abdomen is shallower than that of the subject's head, and the distance in the anterior-posterior direction between position Pc on tabletop 14A and position Pd of the subject's abdomen is smaller than the distance La in the anterior-posterior direction between position Paa directly below position Pa of the vertex Par and position Pb on tabletop 14A. In this case, tabletop 14A appears to move to approximately the expected position, but the calculation of the amount of movement of tabletop 14A needs to be improved. The same applies to chest measurement as to abdominal measurement.

[0239] 29 is an explanatory diagram of how the scanogram capture start position is detected when measuring the head. The scanogram capture start position is determined based on the center position of the camera image. The center position of the camera image is the intersection of the lateral guide GX and the front-to-back guide GY shown in FIG. 16 and other figures.

[0240] 29 is a virtual line segment LS1 extending directly downward from camera 27. That is, the position on line segment LS1 represents the center position of the camera image for each height of tabletop 14A.

[0241] Furthermore, line segment LS2 extending diagonally downward from camera 27 is an imaginary line segment connecting pixels that always appear at the same position in the camera image. That is, the position on line segment LS2 appears to be the same position in the camera image for each height of tabletop 14A. For example, the number of pixels PN1 from the center position of the camera image in the front-to-back direction of position Pe on line segment LS2 is the same as the number of pixels PN2 from the center position of the camera image in the front-to-back direction of position Pf.

[0242] Therefore, when calculating the movement amount of the tabletop 14A, the length-pixel conversion value at the height of the tabletop 14A at position Pe is used instead of the length-pixel conversion value at the height of the tabletop 14A at position Pf. Specifically, this can be addressed by changing the calculation formula used to calculate the movement amount in the front-to-back direction.

[0243] 30 is a schematic diagram of detecting the scanogram capture start position when measuring the head. In calculating the amount of movement of the tabletop 14A in the front-rear direction, the estimated value H_ of the distance from the camera 27 to the tabletop 14A is calculated. estimate Instead, the estimated distance H_ from the camera 27 to the subject's surface SS patient is used.

[0244] The surface SS of the subject described in the embodiment is an example of a surface of the subject that faces the sensor in the measurement target part. patient is an example of the distance information between the sensor measurement target parts.

[0245] Figure 31 is an explanatory diagram of the formula used to detect the scanogram imaging start position. First, the length-pixel conversion value EstimateTableMppP at the height of the subject's surface SS where the scan start position is estimated is calculated. The calculation formula for the length-pixel conversion value EstimateTableMppP is shown as Equation 7 in Figure 31.

[0246] Note that the length-pixel conversion value EstimateTableMppP at the height of the subject's surface SS described in the embodiment is an example of first conversion information that converts the number of pixels in the camera image from the center position of the camera image to the measurement start position of the subject into the distance from the center position of the camera image to the measurement start position.

[0247] Next, using the length-pixel conversion value EstimateTableMppP, the number of pixels from the center position of the camera image to the scan start position is converted to a distance (middle_line_mm, middle_line_st_mm) in units of millimeters or the like. Figure 31 shows, as Equation 8, the calculation formula for middle_line_mm, the distance from the center position of the camera image to the scan start position in the horizontal direction. The same figure also shows, as Equation 9, the calculation formula for middle_line_st_mm, the distance from the center position of the camera image to the scan start position in the front-to-back direction.

[0248] The distance from the center position of the camera image in the front-to-back direction to the scan start position at the height of the subject's surface SS is calculated based on Equation 9 in Fig. 31. Also, the distance from the center position of the camera image in the lateral direction to the scan start position at the height of the subject's surface SS is calculated based on Equation 8 in Fig. 31.

[0249] Furthermore, Fig. 31 illustrates, as Equation 10, the calculation formula for high_table_middle_line_mm, the distance from the center position of the camera image in the horizontal direction to the scan start position at the highest position. Furthermore, Fig. 31 illustrates, as Equation 11, the calculation formula for high_table_middle_line_st_mm, the distance from the center position of the camera image in the front-to-rear direction to the scan start position at the highest position.

[0250] The estimated value H of the distance from the camera 27 to the surface SS of the subject, as shown in FIG. patient is also applied to the calibration when the camera 27 is installed at an angle with respect to the installation surface PP.

[0251] That is, when the camera 27 is tilted with respect to the installation surface PP, the estimated value H_ of the distance from the camera 27 to the top board 14A is estimate is the estimated distance H_ from the camera 27 to the subject's surface SS. patient can be replaced by .

[0252] In addition, the coordinate value Y in the front-rear direction of the estimated position where the distance from the camera 27 to the surface SS of the subject is estimated is estimate is replaced with (Middle_line_st)-PNY, which is the value obtained by subtracting half the number of pixels in the front-to-back direction in the camera image from the coordinate value of the scan start position.

[0253] For example, the estimated value H_ of the distance from the camera 27 to the surface SS of the subject, which is estimated when the camera 27 is tilted with respect to the installation surface PP, patient is applied to Equation 7 shown in FIG.

[0254] Equation 7 is applied to obtain an estimate of the distance H_ from the camera 27 to the subject's surface SS. patient The length pixel conversion value EstimateTableMppP calculated using the above is applied to Equation 8 to calculate the distance middle_line_mm from the center position of the camera image in the horizontal direction to the scan start position.

[0255] Furthermore, the length pixel conversion value EstimateTableMppP is applied to Equation 9 to calculate the distance middle_line_st_mm from the center position of the camera image in the lateral direction to the scan start position in the front-to-back direction.

[0256] Furthermore, for the highest position of the tabletop 14A, the distance high_table_middle_line_mm from the center position of the camera image in the horizontal direction to the scan start position is calculated based on Equation 10. Furthermore, for the highest position of the tabletop 14A, the distance high_table_middle_line_st_mm from the center position of the camera image in the front-to-back direction to the scan start position is calculated based on Equation 11.

[0257] Furthermore, the movement distance of the tabletop 14A in the horizontal direction, move_shift_mm, and the movement distance of the tabletop 14A in the front-to-back direction, move_position_mm, are calculated. Note that the linear function z=a2×x+b2 expressed using the slope a2 and intercept b2 shown in Equation 7 is an example of a linear function that represents the conversion relationship between the number of pixels in the camera image and the distance for each position in the up-down direction.

[0258] [Effects of other embodiments] According to the inspection control device 20 of another embodiment, the estimated value of the distance from the camera 27 to the surface SS of the object when the camera 27 is tilted with respect to the installation surface PP is set to be equal to the estimated value H_ of the distance from the camera 27 to the surface SS of the object at the center position of the camera image when the camera 27 is not tilted with respect to the installation surface PP. patient As a result, the movement distance to the scan start position when the camera 27 is tilted with respect to the installation surface PP is calculated using the calculation method for the movement distance to the scan start position that is applied when the camera 27 is not tilted with respect to the installation surface PP.

[0259] As another embodiment, calculation of the distance traveled to the scan start position of the tabletop 14A when measuring the head is exemplified, but the area to be measured is not limited to the head, and calculation of the distance traveled to the scan start position of the tabletop 14A according to other embodiments can be applied to measurements of the chest, abdomen, waist, and legs.

[0260] The examination control device 20 shown in Fig. 2 calculates the movement amount of the tabletop 14A described as another embodiment. That is, the examination control device 20 functions as a bed movement control device that controls the movement of the bed 14 and the tabletop 14A, and functions as the subject of the bed movement control method.

[0261] [About the programs that run the computer] A program that causes a computer to realize some or all of the processing functions of the inspection control device 20, etc. in the embodiment can be recorded on a computer-readable medium such as an optical disk, a magnetic disk, a semiconductor memory, or other tangible non-transitory information storage medium, and the program can be provided through this information storage medium.

[0262] Furthermore, instead of providing a program stored on a tangible, non-transitory computer-readable medium, it is also possible to provide a program signal as a download service using a telecommunications line such as the Internet.

[0263] Furthermore, some or all of the processing functions of the inspection control device 20 and the like may be realized by cloud computing, and may also be provided as SaaS (Software as a Service).

[0264] [Application example to medical image diagnostic examination system] 1 may be electrically connected via any network to freely communicate data with the measurement device 12 and the examination control device 20 to form a medical image diagnostic examination system. Data communication between the measurement device 12 and the examination control device 20 may be wired or wireless.

[0265] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the technical idea of ​​the present disclosure. [Explanation of symbols]

[0266] 10...MRI device 12...Measuring equipment 14...Bed 14A...Tabletop 17A...filming room 20...Inspection control device 27...Camera 82...Processor 84...Memory 126...Calibration data generation unit 130...Camera image acquisition unit 132...Camera image processing unit 134…Distance information acquisition unit 136...Distance information processing unit 138...Measurement data acquisition section 140...Measurement data processing section

Claims

1. one or more processors; one or more memories in which a program including one or more instructions executed by one or more processors is stored; Equipped with The one or more processors execute a program stored in the one or more memories, using a sensor attached to a measurement room in which a bed is installed, to acquire sensor-to-measurement target site distance information representing the distance from the sensor to a surface of a measurement target site of a subject placed on a top board of the bed that faces the sensor in a vertical direction perpendicular to the installation surface of the bed; acquire first conversion information for converting the number of pixels in a camera image generated by photographing the subject using a camera attached to the measurement room from a center position of the camera image to a measurement start position of the subject, based on the sensor-to-measurement target portion distance information, into a distance from the center position of the camera image to the measurement start position; a bed movement control device that uses the first conversion information to convert, for the position of the measurement start position of the subject in the vertical direction, the number of pixels in the camera image from the center position of the camera image to the measurement start position into a distance in a plane perpendicular to the vertical direction from the center position of the camera image to the measurement start position.

2. The one or more processors: The bed movement control device according to claim 1 , wherein the first conversion information is obtained as a slope and an intercept of a linear function that represents a conversion relationship between the number of pixels in the camera image and distance for each position in the vertical direction.

3. The linear function is 3. The bed movement control device according to claim 2, wherein the information is derived using home position conversion information representing the vertical position at the home position where the tabletop is lowest, the conversion relationship between the number of pixels and distance at the home position, the vertical position at the highest position where the tabletop is highest raised, and maximum position conversion information representing the conversion relationship between the number of pixels and distance at the highest position.

4. The one or more processors: The bed movement control device according to claim 1 , further comprising: a distance from a center position of the camera image to the measurement start position in a movement direction of the tabletop that is parallel to a plane perpendicular to the up-down direction.

5. The one or more processors: acquire second conversion information representing a variation in the distance from the sensor to the tabletop for each position relative to a center position of the camera image in the moving direction of the tabletop; 2. A bed movement control device as described in claim 1, wherein, when the sensor is mounted at an angle relative to the installation surface, the acquired distance from the sensor to the tabletop is corrected using the amount of change in the position in the movement direction of the tabletop from which the distance was derived.

6. The one or more processors: A bed movement control device as described in claim 1, which acquires the movement distance of the tabletop in the movement direction of the tabletop when moving the measurement start position of the subject to a specified position in a measurement device that measures the subject based on the distance from the center position of the camera image to the measurement start position of the subject.

7. The bed movement control device according to claim 6, wherein the predetermined position is a position where scanogram imaging is started.

8. using a sensor attached to a measurement room in which a bed is installed, to acquire sensor-to-measurement target site distance information representing the distance from the sensor to a surface of a measurement target site of a subject placed on the bed that faces the sensor in a vertical direction perpendicular to a surface on which the bed is installed; acquire first conversion information for converting the number of pixels in a camera image generated by photographing the subject using a camera attached to the measurement room from a center position of the camera image to a measurement start position of the subject, based on the sensor-to-measurement target portion distance information, into a distance from the center position of the camera image to the measurement start position; A bed movement control method, using the first conversion information, converting the number of pixels in the camera image from the center position of the camera image to the measurement start position into a distance in a plane perpendicular to the up-down direction from the center position of the camera image to the measurement start position for the position of the subject in the up-down direction.

9. On the computer, a function of acquiring, using a sensor attached to a measurement room in which a bed is installed, information on the distance between the sensor and the measurement target site, which indicates the distance from the sensor to the surface of the measurement target site of the subject placed on the bed that faces the sensor, in a vertical direction perpendicular to the installation surface of the bed; a function of acquiring first conversion information for converting the number of pixels in a camera image, generated by photographing the subject using a camera attached to the measurement room, from the center position of the camera image to a measurement start position of the subject, into a distance from the center position of the camera image to the measurement start position, based on the information on the distance between the sensor and measurement target portions; and a program that uses the first conversion information to realize a function of converting, for the vertical position of the measurement start position of the subject, the number of pixels in the camera image from the center position of the camera image to the measurement start position into a distance in a plane perpendicular to the vertical direction from the center position of the camera image to the measurement start position.

10. a measurement device for measuring the subject; a measurement data processing device that generates a medical image of the subject based on the measurement results of the subject; a bed provided with a top plate on which the subject can be placed; a sensor attached to a measurement room in which the bed is installed, the sensor acquiring a distance from the sensor to an object to be measured; a camera that captures an image of the subject placed on the tabletop and generates a camera image; a bed movement control device for controlling the movement of the bed; Equipped with The bed movement control device includes: one or more processors; one or more memories in which a program including one or more instructions executed by one or more processors is stored; Equipped with The one or more processors execute a program stored in the one or more memories, using a sensor attached to a measurement room in which a bed is installed, to acquire sensor-to-measurement target site distance information representing the distance from the sensor to a surface of a measurement target site of a subject placed on the bed that faces the sensor in a vertical direction perpendicular to a surface on which the bed is installed; acquire first conversion information for converting the number of pixels in a camera image generated by photographing the subject using a camera attached to the measurement room from a center position of the camera image to a measurement start position of the subject, based on the sensor-to-measurement target portion distance information, into a distance from the center position of the camera image to the measurement start position; a medical imaging device that uses the first conversion information to convert, for the position of the measurement start position of the subject in the vertical direction, the number of pixels in the camera image from the center position of the camera image to the measurement start position into a distance in a plane perpendicular to the vertical direction from the center position of the camera image to the measurement start position.

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