Radiation imaging system

Abstract

To smoothly adjust a direction of a bulb relative to a radiation imaging device.SOLUTION: A system 100 includes an optical imaging unit (optical camera) 2A for acquiring an optical image. The system 100 includes display units 28 and 31 for displaying the optical image acquired by the optical imaging unit 2A. The system 100 includes a bulb (radioactive ray irradiation unit) 23 for emitting a radioactive ray R to an imaging device 1 for generating a radiation image. The system 100 includes a second control unit (angle information calculation unit) 211 for calculating angle information in right and left, and vertical directions of the imaging device 1 with respect to an irradiation direction of the radioactive ray R by the bulb 23. The second control unit 211 displays predetermined information based on the calculated angle information in the right and left, and vertical directions of the imaging device 1 and the optical image in the display units 28 and 31 in an overlapped manner.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to a radiography system. [Background technology]

[0002] A mobile radiography system called a medical cart is sometimes used to perform radiography on subjects, for example, while they are lying on a bed in a hospital ward. When performing radiography on a bed, the imaging surface of a portable (panel-shaped) radiography device placed between the subject's back and the bed may not necessarily be parallel or perpendicular to the horizontal plane (it may be tilted). Even in such cases, it is necessary to adjust the orientation of the tube relative to the radiography device so that the radiation irradiation axis is perpendicular to the imaging surface of the device to prevent density differences in the radiography image due to cutoff of a grid attached to the radiation entrance surface and to prevent changes in the positional relationship of the subject's internal structures as viewed on the radiography device from affecting the diagnosis.

[0003] For example, Patent Document 1 discloses that the attitude of the tube (radiation source) and the radiographic imaging device are displayed on the liquid crystal display means of the tube in order to make it easier to adjust the orientation of the tube (radiation source) relative to the radiographic imaging device (cassette). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-23955 Summary of the Invention [Problem to be solved by the invention]

[0005] In the technology disclosed in Patent Document 1, the information indicating the attitude is only displayed numerically as the horizontal and vertical rotation angles of the radiographic imaging device and the rotation angle around the axis of the line segment connecting the tube and the radiographic imaging device, making it difficult to intuitively grasp the attitude, which poses a problem in that the orientation of the tube relative to the radiographic imaging device cannot be smoothly adjusted.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to smoothly adjust the orientation of a tube relative to a radiation image capturing device. [Means for solving the problem]

[0007] In order to solve the above problems, a radiation imaging system according to the present invention comprises: an optical camera for acquiring an optical image; a display unit that displays an optical image acquired by the optical camera; a radiation irradiation unit that irradiates radiation to a radiation image capturing device that generates a radiation image; an angle information calculation unit that calculates angle information in left, right, up, and down directions of the radiographic image capturing device relative to the radiation irradiation direction of the radiation irradiation unit; a display control unit that displays, on the display unit, predetermined information based on angle information in the left-right and up-down directions of the radiation image capturing device calculated by the angle information calculation unit and the optical image superimposed thereon; Equipped with. [Effects of the Invention]

[0008] According to the present invention, the orientation of the tube relative to the radiation image capturing device can be smoothly adjusted. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a side view illustrating an example of a radiation imaging system according to an embodiment of the present invention. [Figure 2] 2 is a perspective view showing a radiation image capturing device shown in the radiation imaging system of FIG. 1. FIG. [Figure 3]FIG. 3 is a block diagram showing the radiographic image capturing apparatus of FIG. 2. [Figure 4] 2 is a block diagram showing a radiation generating device and a console included in the radiation imaging system of FIG. 1. FIG. [Figure 5] 10 is a flowchart showing the flow of angle information preparation processing. [Figure 6A] FIG. 2 is a diagram showing the X-axis and Y-axis of a three-axis acceleration sensor provided in the radiographic image capturing device. [Figure 6B] 10 is a diagram showing the inclination of the X-axis of a three-axis acceleration sensor provided in the radiographic image capturing device relative to the horizontal plane. FIG. [Figure 6C] 10 is a diagram showing the inclination of the Y axis of a three-axis acceleration sensor provided in the radiographic image capturing device relative to the horizontal plane. FIG. [Figure 7A] 10A and 10B are diagrams illustrating a method for determining the orientation of a radiographic image capturing device. [Figure 7B] 10A and 10B are diagrams illustrating a method for determining the orientation of a radiographic image capturing device. [Figure 7C] 10A and 10B are diagrams illustrating a method for determining the orientation of a radiographic image capturing device. [Figure 7D] 10A and 10B are diagrams illustrating a method for determining the orientation of a radiographic image capturing device. [Figure 8A] FIG. 2 is a diagram for explaining the relationship between the orientation of the radiographic image capturing device and roll / pitch. [Figure 8B] FIG. 2 is a diagram for explaining the relationship between the orientation of the radiographic image capturing device and roll / pitch. [Figure 8C] FIG. 2 is a diagram for explaining the relationship between the orientation of the radiographic image capturing device and roll / pitch. [Figure 8D] FIG. 2 is a diagram for explaining the relationship between the orientation of the radiographic image capturing device and roll / pitch. [Figure 9] 10 is a table showing the relationship between the orientation of the radiographic image capturing device and the roll / pitch. [Figure 10A] 10A and 10B are diagrams showing the arrangement of a conventional radiographic image capturing device and angle information at that time. [Figure 10B] 10A and 10B are diagrams showing the arrangement of a conventional radiographic image capturing device and angle information at that time. [Figure 10C] 10A and 10B are diagrams showing the arrangement of a conventional radiographic image capturing device and angle information at that time. [Figure 11] 10 is a flowchart showing the flow of a display control process. [Figure 12] FIG. 10 is a diagram showing an example of an angle information display screen. [Figure 13] FIG. 10 is a diagram showing an example of an angle information display screen. [Figure 14] FIG. 10 is a diagram showing an example of an angle information display screen. [Figure 15] FIG. 10 is a diagram showing an example of an angle information display screen. [Figure 16] FIG. 10 is a diagram showing an example of an angle information display screen. [Figure 17A] 1A and 1B are plan and cross-sectional views of a marker. [Figure 17B] 1A and 1B are plan and cross-sectional views of a marker. [Figure 18] FIG. 1 is a diagram illustrating an example of use of a radiation image capturing apparatus. [Figure 19] FIG. 1 is a diagram illustrating an example of use of a radiation image capturing apparatus. [Figure 20A] 10A and 10B are diagrams for explaining a method for calculating the pitch angle of the imaging device relative to the tube. [Figure 20B] 10A and 10B are diagrams for explaining a method for calculating the pitch angle of the imaging device relative to the tube. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the technical scope of the present invention is not limited to the following embodiments and illustrated examples.

[0011] <1. Radiography System> First, the schematic configuration of a radiography system (hereinafter referred to as a system 100) according to this embodiment will be described using an example in which the system 100 is configured as a medical examination cart. FIG. 1 is a block diagram showing a system 100, and FIG. 2 is a perspective view showing a radiographic image capturing device 1 provided in the system 100. As shown in FIG.

[0012] 1, the system 100 includes, for example, a radiographic imaging device (hereinafter referred to as imaging device 1), a radiation generating device (hereinafter referred to as generating device 2), and a console 3. The devices 1 to 3 are capable of communicating with each other via, for example, a communication network (such as a LAN (Local Area Network), a WAN (Wide Area Network), or the Internet).

[0013] The system 100 may be capable of communicating with a Hospital Information System (HIS), a Radiology Information System (RIS), etc. The system 100 may also be capable of communicating with a Picture Archiving and Communication System (PACS), a dynamic analysis device, etc. The communication network may be wired or wireless.

[0014] [1-1. Radiation imaging device] The imaging device 1 generates a radiographic image corresponding to the radiation R received from the generator 2. As shown in FIGS. 1 and 2, the imaging device 1 according to this embodiment is configured in a panel shape and is portable. Therefore, the imaging device 1 according to this embodiment can not only be used by being mounted on an imaging table, but also by being placed horizontally between a subject S who is lying on a bed B and the bed B. As shown in FIG. 1, the imaging device 1 can also be placed upright between a partially upright bed B or a wheelchair-mounted subject S who is sitting on the bed and the backrest. There are two types of imaging tables: a table-like imaging table for lying on a bed and a stand-type imaging table for standing on a bed (wall stand).

[0015] The radiation incident surface 1a (surface facing the subject S) of the imaging device 1 mounted on the imaging table is parallel or perpendicular to the horizontal plane. However, when imaging is performed without using an imaging table (on a bed B or in a wheelchair), the radiation incident surface 1a may not necessarily be parallel or perpendicular to the horizontal plane (may be tilted). Furthermore, when the imaging device 1 is positioned between a soft device such as bed B and the subject S, it may move in accordance with the movement of the subject S. Details of the imaging device 1 will be described later.

[0016] [1-2. Radiation Generator] As shown in Fig. 1, the generator 2 includes a generator main body 21, an irradiation instruction switch 22, and a tube 23. The generator 2 according to this embodiment further includes a tube support section 24, a collimator 25, and a storage section 26. The generator 2 according to this embodiment is movable by wheels provided on the housing. Details of the generator main body 21 will be described later.

[0017] The irradiation instruction switch 22 is configured to output an operation signal to the generator main body 21 when operated (pressed) by the user U. Note that, although Fig. 1 illustrates a state in which the irradiation instruction switch 22 is connected to the generator main body 21 by wire, the irradiation instruction switch 22 and the generator main body 21 may be connected wirelessly.

[0018] When the irradiation instruction switch 22 is operated, the tube 23 generates radiation R (e.g., X-rays) at a dose corresponding to the preset imaging conditions in a manner corresponding to the imaging conditions, and irradiates it from the irradiation port.

[0019] The tube support 24 supports the tube 23. The tube support 24 according to this embodiment has a first support 241 extending upward from the generator main body 21 to its tip, and a second support 242 extending forward from the top of the first support 241. The tip of the second support 242 supports the tube 23. The tube support 24 also has a joint mechanism (not shown), which allows the tube 23 to move in the X-axis direction (the front-to-rear direction of the generator 2 (the left-to-right direction in FIG. 1)). The tube support 24 also has the above-mentioned joint mechanism, which allows the tube 23 to move in the Y-axis direction (the width direction of the generator 2 (the direction perpendicular to the plane of the paper in FIG. 1)), which is perpendicular to the X-axis. Furthermore, by having the above-mentioned joint mechanism, tube support part 24 is able to move tube 23 in the Z-axis direction (vertical direction (up and down direction in Figure 1)) which is perpendicular to the X-axis and Y-axis. Furthermore, tube support part 24 is able to rotate tube 23 around a rotation axis parallel to the X-axis, Y-axis, and Z-axis by using a joint mechanism (not shown), thereby changing the direction of the radiation R irradiation port.

[0020] Collimator 25 is attached to the irradiation port of tube 23 and is configured to narrow down radiation R so that the irradiation field of radiation R irradiated from the irradiation port has a predetermined rectangular shape. Collimator 25 also has a lamp button (not shown). When the lamp button is operated by a user, visible light is irradiated onto the range that will become the irradiation field of radiation R.

[0021] The storage section 26 stores the imaging device 1 when not in use. The storage section 26 according to this embodiment is provided on the side of the generator main body 21. The storage section 26 according to this embodiment is capable of storing multiple imaging devices 1. A connector (not shown) is provided inside the storage section 26, and when the imaging device 1 is stored, it is connected to the connector 16a (see FIG. 2) of the imaging device 1.

[0022] [1-3.Console] The console 3 is configured by a PC, a mobile terminal, or a dedicated device. As shown in FIG. 1 , the console 3 according to this embodiment is mounted on the generator 2. The console 3 can set imaging conditions for at least one of the imaging device 1 and the generator 2 based on an imaging order received from another system (such as an HIS or RIS). The imaging conditions include tube voltage, tube current and irradiation time or current-time product (mAs value), imaging region, imaging direction, etc. The console 3 can also set imaging conditions for at least one of the imaging device 1 and the generator 2 based on an operation performed on the operation unit 32 by a user U (e.g., a radiologist). The console 3 can acquire image data of a radiographic image generated by the imaging device 1, store the image data in itself, or transmit the image data to another device (such as a PACS or a dynamic analysis device).

[0023] [1-4. Overview of Radiography Using Radiography Systems] Radiography (sitting position radiography) using the system 100 (medical cart) configured as described above is performed as follows. First, the system 100 is placed near the subject S (next to the bed B or wheelchair). Next, the subject S is asked to assume a sitting position. If the subject S is sitting on an angle-adjustable device (such as a partially upright bed B), the angle of the backrest is adjusted appropriately. Next, the approximate position and orientation of the tube 23 is adjusted so that the irradiation port of the tube 23 faces the area to be imaged on the subject S. Next, the imaging device 1 is removed from the storage unit 26 and placed between the back of the subject S and the backrest. Next, while referring to angle information (described in detail below), the orientation and irradiation field of the tube 23 are finely adjusted so that the irradiation axis of the radiation R is perpendicular to the radiation incident surface 1a. Next, still image or video imaging is performed (the area to be diagnosed on the subject S is irradiated with radiation R, and the imaging device 1 is caused to generate a radiographic image depicting the area to be diagnosed). In this embodiment, still image capture refers to acquiring one image of the subject S in response to a single capture operation. Video capture, which is the counterpart of still image capture, refers to continuously acquiring multiple images of the subject S in response to a single capture operation to obtain a moving image. The real-time display of the images acquired through capture and the capture time are not restricted. Video capture also includes dynamic capture (also referred to as serial capture), in which multiple images of the subject S are acquired by a single capture operation by repeatedly irradiating the subject S with pulsed radiation such as X-rays at predetermined intervals (pulse irradiation) or by continuously irradiating the subject S without interruption at a low dose rate (continuous irradiation). A series of images acquired through dynamic capture are called dynamic images. When dynamic capture is performed, image data of the dynamic images is transmitted to a dynamic analysis device as needed to analyze the dynamics of the imaged area (such as the ventilation function / blood flow state of the lungs and the flexion and extension of joints).

[0024] The generator main body 21 and the console 3 may be integrated (or housed in a single housing). The generator 2 may be movable by means other than wheels. For example, the generator 2 may be lightweight enough to be portable or to be mounted on a commercially available dolly, or may have a smooth bottom surface that slides on the floor. In the system 100, one of the imaging device 1 and the generator 2 may be installed in an imaging room or the like of a medical facility (the other device may be freely movable).

[0025] <2. Details of the radiation imaging device> Next, a detailed description will be given of the photographing device 1 provided in the system 100. FIG.

[0026] [2-1. Specific configuration of the radiation imaging device] 3, the imaging device 1 includes a radiation detection unit 11, a scan driver 12, a readout unit 13, a first control unit 14, a first storage unit 15, a first communication unit 16, and a first sensor unit 17. The units 11 to 17 are electrically connected to each other.

[0027] The radiation detection unit 11 includes a scintillator (not shown) and a photoelectric conversion panel 111. The scintillator is formed in a flat plate shape using, for example, columnar crystals of CsI. When exposed to radiation, the scintillator emits electromagnetic waves (for example, visible light) with a wavelength longer than that of the radiation, with an intensity corresponding to the dose (kV, mAs, etc.) of the received radiation. The scintillator is arranged to extend parallel to the radiation incident surface 1a of the housing (see FIG. 2).

[0028] The photoelectric conversion panel 111 is disposed on the side of the scintillator opposite the surface facing the radiation incidence surface 1a, extending parallel to the scintillator. The photoelectric conversion panel 111 includes a substrate 111a and a plurality of charge accumulation sections 111b. The plurality of charge accumulation sections 111b are arranged two-dimensionally (e.g., in a matrix) on the surface of the substrate facing the scintillator, corresponding to each pixel of the radiation image. Each charge accumulation section 111b includes a semiconductor element that generates an amount of charge corresponding to the intensity of the electromagnetic waves generated by the scintillator, and a switch element provided between each semiconductor element and wiring connected to the readout section 13. A bias voltage is applied to each semiconductor element from a power supply circuit (not shown). Each charge accumulation section stores and releases charge to be read out as a signal value according to the received radiation by switching the switch element between on and off.

[0029] The scan driver 12 is capable of switching each switch element between an on state and an off state by applying an on voltage or an off voltage to each scan line 111c of the radiation detection unit 11.

[0030] The readout unit 13 is configured to read out, as a signal value, the amount of charge that has flowed in from the charge accumulation unit 111b via each signal line 111d of the radiation detection unit 11. Note that the readout unit 13 may be configured to perform binning when reading out the signal value.

[0031] The first control unit 14 includes a CPU (Central Processing Unit) and RAM (Random Access Memory), not shown. The CPU reads out various processing programs stored in the first storage unit 15, loads them into the RAM, and executes various processes in accordance with the processing programs, thereby comprehensively controlling the operation of each unit of the imaging device 1. The first control unit 14 also generates image data of a radiographic image based on the multiple signal values ​​read out by the readout unit 13.

[0032] The first storage unit 15 is configured with an HDD (Hard Disk Drive), a semiconductor memory, etc. The first storage unit 15 also stores various programs executed by the first control unit 14, as well as parameters, files, etc. required for executing the programs. The first storage unit 15 may also be capable of storing image data of radiographic images.

[0033] The first communication unit 16 is configured with a communication module, etc. The first communication unit 16 is capable of transmitting and receiving various signals and various data to and from other devices (the generator 2, the console 3, etc.) connected by wire or wirelessly via a communication network.

[0034] The first sensor unit 17 detects information necessary for calculating angle information. The first sensor unit 17 according to this embodiment is a triaxial acceleration sensor. The triaxial acceleration sensor detects acceleration acting in three axial directions (x-axis, y-axis, and z-axis) as information necessary for calculating angle information, and transmits this information to the first control unit 14. Only gravitational acceleration acts on the triaxial acceleration sensor in a stationary state. Therefore, the triaxial acceleration sensor detects each of the three axial components of gravitational acceleration in a stationary state.

[0035] [2-2. Specific operation of the radiation imaging device] The first control section 14 of the photographing device 1 configured as above operates as follows.

[0036] For example, when a predetermined condition is met, the first control unit 14 causes the first sensor unit 17 to repeatedly detect the three-axis components of the gravitational acceleration. The predetermined condition includes, for example, turning on the power of the image capturing device 1, receiving a predetermined control signal from another device (the generator 2, the console 3, etc.), performing a predetermined operation on the operation unit of the image capturing device 1, etc.

[0037] The first control unit 14 also controls the scan driver 12 to accumulate and release charges in the radiation detection unit 11 in synchronization with the timing of irradiation of radiation R from the generator 2. The first control unit 14 also controls the readout unit 13 to read signal values ​​based on the charges emitted by the radiation detection unit 11. The first control unit 14 also generates a radiographic image corresponding to the dose distribution of the irradiated radiation R based on the signal values ​​read out by the readout unit 13. When generating a still image, the first control unit 14 generates a radiographic image only once per press of the irradiation instruction switch 22. When generating a dynamic image, the first control unit 14 repeats the generation of frames constituting the dynamic image multiple times per predetermined time (e.g., 15 times per second) per press of the irradiation instruction switch 22. The first control unit 14 also transmits image data of the generated radiographic image to another device (such as the console 3 or a dynamic analysis device) via the first communication unit 16.

[0038] The radiation detection unit 11 of the imaging device 1 may not include a scintillator, but may be configured to directly generate charges when a semiconductor element is exposed to radiation. Also, the imaging device 1 may display the generated dynamic images in real time (for example, as a fluoroscopic image) on a display device connected to the imaging device 1, rather than converting the generated dynamic images into image data.

[0039] Furthermore, the output value of the first sensor unit 17 (triaxial acceleration sensor) of the imaging device 1 may exhibit a slight tilt even when the radiation incident surface 1a is parallel to an ideal horizontal plane. This is due to the influence of the mounting state of the radiation detection unit 11 on the substrate 111a, the attachment state of the radiation detection unit 11 within the imaging device 1, distortion of the housing of the imaging device 1, and the like. Furthermore, if the imaging device 1 is subjected to an impact (for example, dropped) while being carried, the above-mentioned influence that causes the output value to exhibit a tilt may newly occur or the degree of the above-mentioned influence may change. Therefore, the first control unit 14 may be configured to correct (perform calibration) the detection value of the first sensor unit 17 output to the generator 2. Specifically, the first control unit 14 corrects the output value so that it indicates no tilt when the imaging device 1 is placed on an ideal horizontal plane. Alternatively, when the photographing device 1 is stored in a location where the tilt angle with respect to an ideal horizontal plane is known (for example, in the storage section 26 of the medical cart), the first control section 14 corrects the output value so as to indicate that the photographing device 1 is tilted at a known tilt angle. Then, the first control section 14 stores the correction data obtained by the correction in the first storage section 15. The correction is performed, for example, when the photographing device 1 is initially installed, or after the photographing device 1 has been subjected to an impact, and no correction data is stored in the first storage section 15 of the photographing device 1.

[0040] The first control unit 14 may be configured to automatically perform the correction when it detects that the photographing device 1 has been stored in the storage unit 26. The first control unit 14 may also be configured to prompt the user U to perform the correction (for example, by displaying text prompting the user). In this case, the first control unit 14 may also be configured to prompt the user U to perform the correction only when it is determined that the magnitude of the deviation of the calculated angle information from the specified value of the rotation angle with respect to the horizontal plane when the photographing device 1 was stored in the storage unit 26 exceeds an allowable range.

[0041] <3. Details of the radiation generator and console> Next, the generator 2 and the console 3 included in the system 100 will be described in detail.

[0042] [3-1. Specific configuration of radiation generating device] 4, the generator 2 includes the generator main body 21, irradiation instruction switch 22, tube 23, tube support 24, collimator 25, and storage section 26, as well as a second sensor section 27, a sub-display section 28, a distance measurement section 29, and an optical photographing section (optical camera) 2A. The generator main body 21 of the generator 2 also includes a second control section 211, a second storage section 212, a generator 213, and a second communication section 214.

[0043] The second sensor unit 27 according to this embodiment is a three-axis acceleration sensor similar to the first sensor unit 17. However, the second sensor unit 27 may be a six-axis sensor or a nine-axis sensor. Furthermore, the sensor constituting the second sensor unit 27 may be of a different type from the sensor constituting the first sensor unit 17.

[0044] Sub-display unit 28 is configured with a monitor such as an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube). Sub-display unit 28 displays various images and information according to instructions of a display signal input from second control unit 211. Sub-display unit 28 according to this embodiment is provided in the housing of collimator 25. Note that sub-display unit 28 may be provided in the housing of tube 23 or in tube support unit 24.

[0045] The distance measurement unit 29 measures the SID or SSD. The SID (source image distance) is the distance between the focus of the radiation R and the imaging surface 11a of the imaging device 1 (the surface on which the charge accumulation unit 111b in the radiation detection unit 11 is provided). The SSD (source skin distance) is the distance between the focus of the radiation R and the body surface of the subject S, and is approximately equal to the difference between the SID and the body thickness of the subject S. The distance measurement unit 29 according to this embodiment is provided in the collimator 25.

[0046] The distance measurement unit 29 is a depth camera including a light-emitting device that emits laser light, a detection device that detects the reflected laser light, and a calculation device that calculates the distance from the light-emitting device to the reflection point based on the time between the emission of the laser light and the detection of the reflected laser light. The distance measurement unit 29 may also include an optical camera that captures the image capture device 1 in the direction of radiation irradiation and a calculation device that calculates the SID based on the optical image of the image capture device 1 generated by the optical camera and size information of the image capture device 1, or a combination of these. Because the laser light reflects off the body surface of the subject S, the distance measured by the distance measurement unit 29 using the laser light is often the SSD. In this case, the SID is calculated by adding the measured SSD to the body thickness of the subject S. The body thickness may be a predetermined reference value, a value entered by the user, or a value automatically calculated from information about the subject S.

[0047] The optical photographing unit 2A has an optical system such as a lens, and an imaging element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). Under the control of the second control unit 211, the optical photographing unit 2A optically photographs the subject S with visible light to generate optical image data and outputs the data to the second control unit 211, etc. For example, the optical photographing unit 2A optically photographs the subject S to generate optical image data of a still image or dynamic images (such as live images).

[0048] The second control unit 211 is configured with a CPU, RAM, etc. The CPU of the second control unit 211 reads out various programs stored in the second storage unit 212, expands them in the RAM, executes various processes in accordance with the expanded programs, and centrally controls the operations of each unit of the generating device 2.

[0049] The second storage unit 212 is configured by a non-volatile memory, a hard disk, etc. The second storage unit 212 also stores various programs executed by the second control unit 211, parameters required for executing the programs, files, etc.

[0050] Upon receiving an imaging instruction signal from the second control unit 211, the generator 213 applies a voltage to the tube 23 according to the preset imaging conditions and also passes a current to the tube 23 according to the imaging conditions.

[0051] The second communication unit 214 is configured with a communication module, etc. The second communication unit 214 is capable of transmitting and receiving various signals and various data to and from other devices (the image capture device 1, the console 3, etc.) connected by wire or wirelessly via a communication network.

[0052] [3-2. Specific console configuration] The console 3 includes a control unit, a storage unit, a communication unit, a main display unit 31, an operation unit 32, and an audio output unit 33. The control unit, storage unit, and communication unit of the console 3 according to this embodiment are respectively served as the second control unit 211, the second storage unit 212, and the second communication unit 214 of the generating device 2. Note that the console 3 may include dedicated control units, storage units, and communication units.

[0053] The main display unit 31 is composed of a monitor such as an LCD or CRT. The main display section 31 displays various images, various information, and the like in accordance with instructions of a display signal input from the second control section 211.

[0054] The operation unit 32 is configured to be operable by the user. The operation unit 32 includes, for example, a keyboard (cursor keys, numeric input keys, various function keys, etc.), a pointing device (mouse, etc.), a touch panel laminated on the surface of the main display unit 31, etc. The operation unit 32 is configured to output a control signal to the second control unit 211 in accordance with an operation performed by the user.

[0055] The audio output unit 33 is composed of an amplifier, a speaker, etc., and outputs audio in accordance with the audio information input from the second control unit 211. For example, the audio output unit 33 outputs a synthesized voice message as imaging support information, which is information for supporting the user U in radiography.

[0056] [3-3. Specific operation of the radiography system] The second control unit 211 of the generating device 2 (console 3) configured as above operates as follows.

[0057] [3-3-1. Angle information preparation process] When a predetermined condition is satisfied, the second control unit 211 starts or resumes, for example, the angle information preparation process shown in Fig. 5. The predetermined conditions for starting the angle information preparation process include, for example, the power supply of the generating device 2 being turned on, communication with the imaging device 1 being enabled, and a predetermined operation being performed on the operation unit 32 of the console 3. In addition, the predetermined conditions for resuming the angle information preparation process include, for example, the completion of irradiation with radiation R and the selection of an imaging order via the operation unit 32 of the console 3.

[0058] When the angle information preparation process is started, the second control unit 211 first determines whether or not the photographing device 1 is equipped with the first sensor unit 17 (step S1). Specifically, the second control unit 211 determines whether or not the photographing device 1 is equipped with the first sensor unit 17 by referring to the presence / absence information of the first sensor unit 17 stored in the photographing device 1. Note that the second control unit 211 may also refer to the photographing device ID stored in the photographing device 1 and comparison information on the presence / absence of the photographing device 1 and the first sensor unit 17 stored in another device (such as the console 3).

[0059] In step S1, if it is determined that the photographing device 1 does not have the first sensor unit 17 (step S1; NO), the second control unit 211 ends the angle information preparation process (does not permit the display of angle information of the photographing device 1 relative to the tube 23). In other words, it does not permit the display of angle information of the photographing device 1 relative to the tube 23. As a result, when using a photographing device that does not have the first sensor unit 17, the angle information of the photographing device relative to the tube 23 will not be displayed, thereby preventing misunderstanding by the user U.

[0060] Furthermore, if it is determined in step S1 that the photographing device 1 is equipped with the first sensor unit 17 (step S1; YES), the second control unit 211 acquires gravitational acceleration information from the first sensor unit 17 (step S2). Furthermore, the second control unit 211 acquires gravitational acceleration information from the second sensor unit 27 (step S2). Here, the gravitational acceleration information acquired from the first sensor unit 17 is information indicating the three-axis components of the gravitational acceleration detected by the first sensor unit 17. The gravitational acceleration information acquired from the second sensor unit 27 is information indicating the three-axis components of the gravitational acceleration detected by the second sensor unit 27.

[0061] Next, second control unit 211 calculates angle information of each of image capture device 1 and tube 23 with respect to the horizontal plane (step S3). Specifically, as shown in FIG. 6B, second control unit 211 calculates the tilt φ (pitch angle) of the X-axis (Ax; see FIG. 6A) of the triaxial acceleration sensor serving as first sensor unit 17 with respect to the horizontal plane, using the following formula (1), as angle information of image capture device 1. Hereinafter, the tilt φ of the X-axis (Ax; see FIG. 6A) of the triaxial acceleration sensor serving as first sensor unit 17 with respect to the horizontal plane may be referred to as the pitch angle before switching. Furthermore, second control unit 211 calculates the tilt θ (roll angle) of the Y-axis (Ay; see FIG. 6A) of the triaxial acceleration sensor serving as first sensor unit 17 with respect to the horizontal plane, as angle information of image capture device 1, using the following formula (2), as shown in FIG. 6C. Hereinafter, the tilt θ of the Y axis (Ay; see FIG. 6A) of the three-axis acceleration sensor that is first sensor unit 17 relative to the horizontal plane may be referred to as the roll angle before switching. Similarly, second control unit 211 calculates angle information of bulb 23.

number

[0062] Next, the second control unit 211 switches the angle information of the photographing device 1 depending on the orientation of the photographing device 1 (step S4). Specifically, the second control unit 211 first determines the orientation of the photographing device 1 from the gravitational acceleration output by the three-axis acceleration sensor (first sensor unit 17). For example, when |Ax|≦|Ay| and Ay≧0, the second control unit 211 determines that the orientation of the photographing device 1 is upward. Here, upward refers to a state in which the photographing device 1 is vertically oriented and the triangle mark of the photographing device 1 is facing upward, as shown in FIG. 7A. Furthermore, when |Ax|≦|Ay| and Ay<0, the second control unit 211 determines that the orientation of the photographing device 1 is downward. Here, downward refers to a state in which the photographing device 1 is vertically oriented and the triangle mark of the photographing device 1 is facing downward, as shown in FIG. 7B. Furthermore, when |Ax|>|Ay| and Ax>0, the second control unit 211 determines that the orientation of the photographing device 1 is 90 degrees left. Here, 90 degrees to the left means a state in which the photographing device 1 is oriented horizontally and the triangle mark on the photographing device 1 is oriented left, as shown in FIG. 7C. Furthermore, when |Ax|>|Ay| and Ax≦0, the second control unit 211 determines that the orientation of the photographing device 1 is 90 degrees to the right. Here, 90 degrees to the right means a state in which the photographing device 1 is oriented horizontally and the triangle mark on the photographing device 1 is oriented left, as shown in FIG. 7D. Note that the second control unit 211 may determine the orientation of the photographing device 1 based on an image of the photographing device 1 captured by the optical photographing unit 2A.

[0063] Next, as shown in FIGS. 8A and 9, when the orientation of the image capture device 1 is upward, the second control unit 211 outputs the tilt θ of the Y-axis with respect to the horizontal plane calculated in step S3, i.e., the roll angle before switching, as the roll angle after switching. The second control unit 211 also outputs the tilt φ of the X-axis with respect to the horizontal plane, i.e., the pitch angle before switching, as the pitch angle after switching. Here, the roll angle and pitch angle after switching are roll angles and pitch angles that are independent of the X-axis and Y-axis (Ax, Ay; see FIG. 6A) of the triaxial acceleration sensor that is the first sensor unit 17. The roll angle and pitch angle before switching can also be referred to as roll angles and pitch angles whose definitions do not change depending on the orientation of the image capture device 1, and the roll angle and pitch angle after switching can also be referred to as roll angles and pitch angles that depend on the orientation of the image capture device 1. As shown in FIGS. 8B and 9, when the orientation of the image capture device 1 is downward, the second control unit 211 outputs the tilt −θ of the Y-axis with respect to the horizontal plane calculated in step S3, i.e., the roll angle before switching, as the roll angle after switching. The second control unit 211 also outputs the tilt −φ of the X-axis with respect to the horizontal plane, i.e., the pitch angle before switching, as the pitch angle after switching. Furthermore, as shown in FIGS. 8C and 9, when the orientation of the image capturing device 1 is 90 degrees left, the second control unit 211 outputs the tilt φ of the X-axis with respect to the horizontal plane calculated in step S3, i.e., the pitch angle before switching, as the roll angle after switching. Furthermore, as shown in FIGS. 8D and 9, when the orientation of the image capturing device 1 is 90 degrees right, the second control unit 211 outputs the tilt −φ of the X-axis with respect to the horizontal plane calculated in step S3, i.e., the pitch angle before switching, as the roll angle after switching. Furthermore, the second control unit 211 also outputs the tilt θ of the Y-axis with respect to the horizontal plane, i.e., the roll angle before switching, as the pitch angle after switching.

[0064] Here, when the imaging device 1 used is a half-cut size (14 inches × 17 inches), it is usually used in the state shown in FIG. 10A . However, depending on the physique of the subject S, the imaging device 1 may be rotated 90 degrees (90 degrees left) to capture an image as shown in FIG. 10B . Furthermore, because the imaging device 1 has a simple panel shape, the user U may capture an image upside down (rotated 180 degrees) as shown in FIG. 10C without being aware of the upside-down orientation of the imaging device 1 (the generated radiographic image will also be upside-down, but it can be rotated later). Therefore, when the imaging device 1 is used while rotated as described above, the relationship between the roll angle and the pitch angle becomes reversed, or the roll angle or the pitch angle is calculated as a negative value. This may cause problems when fine-tuning the roll angle and pitch angle of the tube 23. Therefore, in step S4, the second control unit 211 switches the angle information of the imaging device 1 according to the orientation of the imaging device 1, i.e., outputs the roll angle and pitch angle after switching, thereby preventing the above-mentioned problems from occurring. From this, the roll angle and pitch angle before switching can also be said to be the roll angle and pitch angle before the definitions of the roll angle and pitch angle of the imaging device 1 are consistent with the definitions of the roll angle and pitch angle of the generating device 2 (tube 23), and the roll angle and pitch angle after switching can also be said to be the roll angle and pitch angle after the definitions of the roll angle and pitch angle of the imaging device 1 are consistent with the definitions of the roll angle and pitch angle of the generating device 2 (tube 23).

[0065] The second control unit 211 detects whether the image capturing device 1 faces the irradiated surface or the non-irradiated surface based on information on the gravitational acceleration of the Z axis of the three-axis acceleration sensor. If the image capturing device 1 faces the non-irradiated surface, the second control unit 211 may stop the processing of step S4 and call the user U's attention (for example, by displaying a warning). After the image capturing device 1 is placed below or behind the subject S, it is impossible to notice whether the image capturing device 1 is upside down until the image capturing is completed. However, by doing so, it is possible to check whether the image capturing device 1 is upside down even when the image capturing device 1 is placed below or behind the subject S, thereby preventing the subject S from failing to capture the image and being unnecessarily exposed to radiation.

[0066] 5, the second control unit 211 determines whether the roll angle of the image capturing device 1 after switching in step S4 (roll angle after switching; angle information) is less than 45 degrees (step S5). That is, it determines whether the pitch angle of the image capturing device 1 after switching in step S4 (pitch angle after switching; angle information) can be used.

[0067] If it is determined in step S5 that the roll angle of imaging device 1 (roll angle after switching) is less than 45 degrees (step S5; YES), angle information of imaging device 1 relative to tube 23 is calculated based on angle information of imaging device 1 and tube 23 (step S6). Here, angle information of imaging device 1 relative to tube 23 means angle information in the left / right, up / down directions of imaging device 1 relative to the irradiation direction of radiation R irradiated from tube (radiation irradiation unit) 23, i.e., angle information in each direction of roll and pitch. Specifically, second control unit 211 calculates the difference between the roll angle of imaging device 1 after switching in step S4 (roll angle after switching) and the roll angle (angle information) of tube 23 calculated in step S3, and calculates this difference as the roll angle (angle information) of imaging device 1 relative to tube 23. Further, second control unit 211 calculates the difference between the pitch angle of imaging device 1 after switching in step S4 (pitch angle after switching) and the pitch angle (angle information) of tube 23 calculated in step S3, and calculates this difference as the pitch angle (angle information) of imaging device 1 relative to tube 23. Hereinafter, the method of calculating the angle information of imaging device 1 relative to tube 23 in step S6 may be referred to as a first angle information calculation method.

[0068] Next, the second control unit 211 determines whether or not at least one of the following termination conditions (1) and (2) is satisfied (step S11). (1) The irradiation instruction switch 22 is operated. (2) Radiation R irradiation has begun. This is because the generated radiographic image is finalized at the time radiation R is irradiated, and there is little need to continue the angle information preparation process or the display control process described below. In particular, in dynamic radiography, radiographic images are often acquired while the patient is performing predetermined movements such as breathing and joint flexion. These movements may cause the radiography device 1 to vibrate or change its tilt, but these changes often do not cause the radiography to be stopped. If the results of the state determination process described below are displayed during radiography, the user U may mistakenly stop the dynamic radiography midway based on the determination results. Therefore, in particular in dynamic radiography, displaying angle information differently before the start of irradiation (non-irradiation) and after the start of irradiation (irradiation) is beneficial in preventing radiography failures. Some types of dynamic imaging require the patient to remain still from the start of irradiation until it is finished (from the start to the end of one dynamic imaging session). For example, in dynamic imaging to observe the state of pulmonary blood flow, the patient is asked to hold their breath and not move during imaging in order to observe minute changes in the lung field associated with pulmonary blood flow, which changes with the heartbeat. In such imaging, changes in angle information during imaging are useful information for determining whether to interrupt imaging, so it is advisable to use "completion of radiation R irradiation, in other words, completion of one imaging session (dynamic imaging)" as the termination condition instead of the above termination condition (2).

[0069] In step S11, if it is determined that the termination condition is not met (step S11; NO), the second control unit 211 returns the process to step S2 and repeats the subsequent processes. That is, the second control unit 211 repeats the calculation of the angle information (roll angle, pitch angle) of the image capturing device 1 with respect to the tube 23 until the termination condition is met.

[0070] Furthermore, in step S11, if it is determined that the termination condition is met (step S11; YES), the second control unit 211 terminates the angle information preparation process.

[0071] Also, in step S5, if it is determined that the roll angle of the photographing device 1 after switching is not less than 45 degrees, i.e., is 45 degrees or more (step S5; NO), the second control unit 211 determines whether the roll angle after switching is 90 degrees or less (step S7).

[0072] If it is determined in step S7 that the roll angle of image capturing device 1 after switching is 90 degrees or less (step S7; YES), second control unit 211 uses distance measurement unit 29 to measure the distance between tube 23 and image capturing device 1 and calculates (outputs) distance information. Specifically, second control unit 211 calculates distance information from distance measurement unit 29 provided in tube 23 to two predetermined points on image capturing device 1 using distance measurement unit 29 (step S8). More specifically, when image capturing device 1 is facing upward, second control unit 211 calculates distance information from distance measurement unit 29 to corner C1 and distance information from distance measurement unit 29 to corner C2 of the four corners C1 to C4 of image capturing device 1, as shown in FIG. 7A. Here, when image capturing device 1 is facing upward, corners C1 and C2 correspond to the two corners on the left and right sides of the top side of image capturing device 1. When the camera device 1 faces upward, the second control unit 211 may calculate distance information from the distance measurement unit 29 to corner C3 and distance information from the distance measurement unit 29 to corner C4. When the camera device 1 faces upward, corners C3 and C4 correspond to two corners, one on the left and one on the right, on the bottom side of the camera device 1. When the camera device 1 faces downward, the second control unit 211 calculates distance information from the distance measurement unit 29 to corner C3 and distance information from the distance measurement unit 29 to corner C4, among the four corners C1 to C4 of the camera device 1, as shown in FIG. 7B . Here, when the camera device 1 faces downward, corners C3 and C4 correspond to two corners, one on the left and one on the top side of the camera device 1. When the camera device 1 faces downward, the second control unit 211 may calculate distance information from the distance measurement unit 29 to corner C1 and distance information from the distance measurement unit 29 to corner C2. When the camera device 1 is facing downward, the corners C1 and C2 correspond to two corners, one on the left and one on the bottom side of the camera device 1. When the camera device 1 is facing 90 degrees left, the second control unit 211 calculates distance information from the distance measurement unit 29 to corner C2 and distance information from the distance measurement unit 29 to corner C4, among the four corners C1 to C4 of the camera device 1, as shown in Fig. 7C. Here, when the camera device 1 is facing 90 degrees left, the corners C2 and C4 correspond to two corners, one on the left and one on the top side of the camera device 1.When the orientation of the camera device 1 is 90 degrees to the left, the second control unit 211 may calculate distance information from the distance measurement unit 29 to corner C1 and distance information from the distance measurement unit 29 to corner C3. When the orientation of the camera device 1 is 90 degrees to the left, corners C1 and C3 correspond to two corners, one on the left and one on the bottom side of the camera device 1. When the orientation of the camera device 1 is 90 degrees to the right, the second control unit 211 calculates distance information from the distance measurement unit 29 to corner C1 and distance information from the distance measurement unit 29 to corner C3, among the four corners C1 to C4 of the camera device 1, as shown in FIG. 7D . Here, when the orientation of the camera device 1 is 90 degrees to the right, corners C1 and C3 correspond to two corners, one on the left and one on the top side of the camera device 1. When the orientation of the camera device 1 is 90 degrees to the right, the second control unit 211 may calculate distance information from the distance measurement unit 29 to corner C2 and distance information from the distance measurement unit 29 to corner C4. When the imaging device 1 is oriented 90 degrees to the right, corners C2 and C4 correspond to the two left and right corners on the bottom side of the imaging device 1. The distance between tube 23 and imaging device 1 may be measured using optical imaging unit 2A provided in tube 23. If the above measurement is performed using distance measurement unit 29 or optical imaging unit 2A, the definition of the measured distance varies depending on the grade and specifications of the radiation imaging system, increasing the development man-hours. Therefore, the measured distance may be converted into the distance from the focal position of radiation R in tube 23. This allows subsequent processing to be standardized regardless of the grade and specifications of the radiation imaging system, thereby reducing the development costs associated with manufacturing the radiation imaging system.

[0073] In radiography (particularly dynamic radiography) in this embodiment, in order to suppress the influence of fluctuations in radiation on dynamic analysis, a direct radiation region (a non-exposed region) where the subject S is not captured is provided for radiography, and the distance information is calculated using this direct radiation region. In other words, the four corners C1 to C4 of the radiography device 1 described above are used as the direct radiation region (a non-exposed region). In this case, the console 3 may be configured to execute a process for correcting the radiographic image based on pixel values ​​of the direct radiation region (a non-exposed region). In other words, the radiographic image is corrected based on pixel values ​​of a region of the irradiation surface of the radiographic image capture device that is used to measure the distance between the radiation irradiator and the radiographic image capture device. Furthermore, in video or dynamic radiography, the console 3 may be configured to execute a process for correcting the radiographic image of each frame based on pixel values ​​of the direct radiation region (a non-exposed region) of that frame. Here, the direct radiation region (a non-exposed region) is recognized by identifying differences in the geometric characteristics of the four corners C1 to C4 from the image. For this reason, the four corners C1 to C4 are each given a different geometric feature. For example, a frame indicating the region in which X-rays can be detected is drawn on the irradiation surface of the imaging device 1, and the four corners of that frame are given different shapes, such as " ", "+", or "T". The four corners C1 to C4 may all be given different shapes, or, for example, two types of shapes, "+" and "T", may be used: upper left +, upper right T, lower left +, and lower right T. By using the combination of the shapes of two adjacent corners, it is possible to determine which side it is, and from there, the four corners can be identified. For example, if the left is + and the right is T, it can be determined to be the top side. If both the left and right are T, it can be determined to be the right side. In other words, it is sufficient to have at least two different geometric features for the shapes of the four corners. The geometric features applied to each of the four corners C1 to C4 should be within the four corners of an 8 cm square. The smaller this size is, the easier it is for the radiographer to secure the direct radiation region (the area exposed to direct radiation) and position themselves. Specifically, 5cm square corners are more preferable than 8cm square corners. 3cm square corners are even more preferable. Also, stickers with marks with different geometric features may be affixed to the four corners C1 to C4 (for example, within the four 8cm square corners) to make them recognizable.In this case, even if the panel is hidden when shooting using a grid, you can address this by attaching a sticker to the grid.

[0074] The locations for calculating the distance information may be two different locations in the horizontal direction (left-right direction), and are not limited to the four corners C1 to C4 of the imaging device 1. The locations for calculating the distance information may be changed depending on the imaging conditions. When calculating the distance information, the second control unit 211 may determine whether a direct radiation area (a non-radiation area) is secured using the optical imaging unit 2A or the distance measurement unit (depth camera) 29. The second control unit 211 may display the determination result on the sub-display unit 28 or output the determination result (audio) from the audio output unit 33, thereby preventing failure in radiography. When it is determined that a direct radiation area (a non-radiation area) is secured, the second control unit 211 may display information (guide information) related to the expected direct radiation area on the sub-display unit 28. The determination result may be used to determine the reliability of the distance information calculated by the distance measurement unit 29 and the pitch angle (angle information) of the imaging device 1 calculated based on the distance information. If the reliability is determined to be low, the display of the angle information of the imaging device 1 relative to the tube 23 may not be permitted, or the display may be displayed in a different manner (e.g., grayed out) than usual (when the reliability is high). Furthermore, if the reliability is low, the reliability information may be reflected in various controls of the system 100, such as by not permitting irradiation of the radiation R or displaying an alert. Furthermore, the distance information is not limited to being calculated using the distance measurement unit 29, but may also be calculated using, for example, the optical imaging unit 2A. Specifically, the optical imaging unit 2A is used to capture images of structures or marks near the irradiation surface in the direct radiation area (non-irradiated area). The distance information is then calculated based on the geometric distortion of the captured images of the structures or marks. In this case, it is preferable to use information linked to the imaging order as the information about the structures or marks.

[0075] Returning to FIG. 5, next, second control unit 211 calculates angle information of imaging device 1 relative to tube 23 based on the angle information of imaging device 1 and tube 23 and the distance information calculated in step S8 (step S9). Here, angle information of imaging device 1 relative to tube 23 means angle information in the left / right, up / down directions of imaging device 1 relative to the irradiation direction of radiation irradiated from tube (radiation irradiation unit) 23, i.e., angle information in each direction of roll and pitch. Specifically, second control unit 211 calculates the difference between the roll angle of imaging device 1 after switching in step S4 (roll angle after switching) and the roll angle (angle information) of tube 23 calculated in step S3, and calculates this difference as the roll angle (angle information) of imaging device 1 relative to tube 23. In addition, second control unit 211 calculates the pitch angle (angle information) of imaging device 1 relative to tube 23 based on the distance information from distance measurement unit 29 to two predetermined locations on imaging device 1 calculated in step S8. Specifically, the pitch angle (cosθ; see FIGS. 20A and 20B) of the imaging device 1 relative to the tube 23 can be calculated using the following formula (a). Note that "e'" in formula (a) can be calculated using the following formula (b). Note that "cosΦ" in formula (b) can be calculated using the following formula (c). Note that "b'" in formula (a) can be calculated using the following formula (d). Note that FIGS. 20A and 20B are diagrams showing the positional relationship between the tube 23 (distance measurement unit 29) and two predetermined locations on the imaging device 1. The Z axis in the diagrams indicates the irradiation axis (optical axis) of the radiation R. Note that the X and Y axes in the diagrams lie on a plane perpendicular to the Z axis and intersect at right angles with each other at the intersection of the Z axis and the plane. The Y axis in the figure is the vertical axis of the rectangular irradiation field of the irradiation ray R, and when the irradiation field R is oriented horizontally and the upper side of the rectangular irradiation field is horizontal, the Y axis is the vertical axis. The X axis is the horizontal axis of the rectangular irradiation field of the irradiation ray R, and when the irradiation field R is oriented horizontally and the upper side of the rectangular irradiation field is horizontal, the X axis is the horizontal axis. Also, "b" in the figure indicates the distance from the tube 23 (distance measurement unit 29) to one of two predetermined locations on the imaging device 1.Furthermore, "c" in the figure indicates the distance from tube 23 (distance measurement unit 29) to the other of the two predetermined locations on imaging device 1. In other words, "b" and "c" in the figure can be said to be the distance information from tube 23 (distance measurement unit 29) to the two predetermined locations on imaging device 1. Furthermore, "e" in the figure indicates the distance between the two predetermined locations on imaging device 1. Hereinafter, the method of calculating the angle information of imaging device 1 relative to tube 23 in step S9 may be referred to as the second angle information calculation method. cosθ=(e 2 +e´ 2 -b´ 2 ) / 2e·e´···(a) e´=(b 2 +c 2 -2b·c·cosΦ) 1 / 2 (b) cosΦ=(b 2 +c 2 -e 2 ) / 2b·c···(c) b´=bc···(d)

[0076] Next, the second control unit 211 determines whether or not the above-mentioned termination condition is met (step S11). If it is determined in step S11 that the termination condition is not met (step S11; NO), the second control unit 211 returns the process to step S2 and repeats the subsequent processes. On the other hand, if it is determined in step S11 that the termination condition is met (step S11; YES), the second control unit 211 ends the angle information preparation process.

[0077] Furthermore, if it is determined in step S7 that the roll angle of the image capturing device 1 after switching is not equal to or less than 90 degrees, i.e., exceeds 90 degrees (step S7; NO), a warning is issued to notify the user that the roll angle after switching exceeds 90 degrees (step S10). Specifically, the second control unit 211 displays a warning message on the sub-display unit 28 notifying the user that the roll angle of the image capturing device 1 after switching exceeds 90 degrees, or outputs the warning message (audio) from the audio output unit 33. The second control unit 211 then proceeds to step S11 and performs subsequent processes. Note that in a standing or sitting position (not a semi-sitting position), the roll angle of the image capturing device 1 after switching approaches 90 degrees and may exceed 90 degrees depending on the inclination of the image capturing device 1. For this reason, the determined angle (roll angle after switching) in step S7 may be set to an angle with a margin of 90 degrees, such as 100 degrees.

[0078] [3-3-2. Angle information preparation processing and others] After calculating the angle information of the imaging device 1 relative to the tube 23 in the angle information preparation process, the second control unit 211 may execute a state determination process. In this state determination process, the second control unit 211 determines whether the angle information of the imaging device 1 relative to the tube 23 is within a predetermined reference range. Here, the determination may be performed only on the pitch angle. In this case, the second control unit 211 may use the determination result as the angle information of the imaging device 1 relative to the tube 23. The second control unit 211 may measure the SID and SSD using the distance measurement unit 29. When measuring the SID and SSD using the distance measurement unit 29, the second control unit 211 may estimate the body thickness of the subject S (body thickness = SID - SSD) from the SID and SSD. The second control unit 211 may determine whether the SID measured by the distance measurement unit 29 is within a predetermined reference range.

[0079] Furthermore, when the above-described state determination process is executed, the second control unit 211 may be configured to determine whether or not the imaging order includes dynamic imaging before executing the state determination process. If it is determined that the imaging order includes dynamic imaging, the second control unit 211 may change (narrow) the reference range used in the subsequent state determination process. This is because dynamic imaging, which is used for dynamic analysis, requires higher alignment accuracy than when capturing still images. Note that, when it is determined that the imaging order includes dynamic imaging, the second control unit 211 may execute the subsequent state determination process, and when it is determined that the imaging order includes still image imaging, the second control unit 211 may not execute the subsequent state determination process. Furthermore, when the state determination process is executed, the second control unit 211 may change the reference range depending on the presence or absence of a grid and its type. This is because a larger grid ratio makes the radiation R more susceptible to oblique incidence (a density difference occurs in the radiographic image due to the cutoff effect of the grid).

[0080] Furthermore, in the angle information preparation process, second control unit 211 executes the calculation process of step S3 once for each execution of the acquisition process of step S2 multiple times. In this calculation process, the average value, median, or the like of the multiple pieces of angle information for each of imaging device 1 and tube 23 may be calculated as the angle information for each of imaging device 1 and tube 23 relative to the horizontal plane. After imaging device 1 is placed below or behind subject S, the angle display fluctuates due to the influence of subject S's breathing, etc. However, by doing so, it is possible to reduce the fluctuation in angle information due to breathing, etc. Furthermore, by reducing the fluctuation in angle information, it is possible to easily fine-tune the orientation of tube 23.

[0081] Furthermore, the calculation method of the angle information of the image capture device 1 relative to the tube 23 in the angle information preparation process is merely an example. The calculation method switches the calculation method for the angle information of the image capture device 1 depending on the attitude of the image capture device 1. Specifically, the calculation method for the pitch angle, which is angle information of the image capture device 1, switches depending on the roll angle of the image capture device 1 after switching. More specifically, the value of the "roll angle after switching" derived in step S4 of the angle information preparation process is compared with a predetermined threshold value, and based on the comparison result, the pitch angle is switched between using the "pitch angle after switching" derived in step S4 of the angle information preparation process or using the pitch angle derived from the distance information calculated in step S8 of the angle information preparation process. When the roll angle is less than the threshold value, the angle information of the image capture device 1, both the roll angle and the pitch angle, are calculated based on gravitational acceleration information from the image capture device 1. When the roll angle is equal to or greater than the threshold value, the angle information of the imaging device 1 is calculated based on the gravitational acceleration information from the imaging device 1, and the pitch angle is calculated based on the distance information from the distance measurement unit 29. In other words, this is a method of calculating the angle information of the radiographic imaging device based on the distance information from the measurement unit (distance measurement unit 29) and / or the gravitational acceleration information from the radiographic imaging device (imaging device 1). It can also be said that the calculation method of the angle information of the radiographic imaging device is switched (selected, determined) based on the gravitational acceleration information from the radiographic imaging device.

[0082] As described above, the pitch angle calculated based on the gravitational acceleration information from the radiography device 1 does not represent the oblique incidence in the left-right direction of the radiography device (radiography device 1) in an arrangement assuming horizontal irradiation, as shown in FIG. 19 , but represents the rotation angle of the radiography device around an axis perpendicular to the irradiation surface of the radiography device. In other words, the closer the roll angle is to 90 degrees, the less the pitch angle calculated based on the gravitational acceleration information from the radiography device 1 is suited to the intended use. On the other hand, the pitch angle calculated based on the above-mentioned distance information measured by the distance measurement unit 29 may become inaccurate when, for example, there is insufficient light-emitting area. This may result in the pitch angle not being able to be derived or its accuracy decreasing. In other words, since both methods have advantages and disadvantages, it is desirable to switch between them appropriately depending on the purpose of imaging and the usage scenario.

[0083] In the above calculation method, the threshold value used for switching is set to 45 degrees, but it can be other than 45 degrees. Of the four main radiography technique classifications (positioning types) of supine radiography, semi-recumbent radiography, sitting radiography, and upright radiography, the roll angle is almost 0 degrees for supine radiography, approximately 30 to 45 degrees for semi-recumbent radiography, 45 to 90 degrees for sitting radiography, and almost 90 degrees for upright radiography. Therefore, if the threshold is set to a value between 10 and 25 degrees, such as 15 degrees, it will be separated into supine radiography and the other three radiography technique classifications. In other words, angle information appropriate for the radiography technique classification is selected, allowing the user to use it without confusion.

[0084] Furthermore, the method of deriving the pitch angle may be switched using the imaging technique classification included in the order information, rather than based on the roll angle, thereby achieving the same ease of use as described above. This can be said to switch (select or decide) the calculation method for angle information of the radiation imaging device (imaging device 1) based on the imaging information (imaging technique classification) of the imaging to be performed. Switching based on the imaging information (imaging technique classification) and switching based on the roll angle threshold value may also be combined. The threshold value used for switching may also be selected depending on the imaging technique classification. The two may also be mixed. For example, when the imaging technique classification is supine position imaging, the pitch angle calculated based on the gravitational acceleration information from the imaging device 1 is always used. When the imaging technique classification is standing position imaging, the pitch angle calculated based on the distance information from the distance measurement unit 29 is always used. When imaging in the semi-sitting or sitting position, switching to the supine position may be considered depending on the patient's condition. Therefore, a switching method based on the roll angle threshold value is used, and the threshold value is set to 15 degrees. In other words, the calculation method for angle information of the radiation imaging apparatus is switched (selected, determined) based on the imaging information (imaging technique classification) of the imaging to be performed and gravitational acceleration information from the radiation image imaging apparatus.

[0085] Furthermore, when a medical cart is brought into a hospital ward or ICU for radiography, there may be almost no radiography performed in a sitting or standing position. In this case, if the threshold value is set to a value between 50 and 75 degrees, such as 60 degrees, the pitch angle calculated based on the gravitational acceleration information from the radiography device 1 is consistently selected during radiography in the ward or ICU. When a medical cart is brought into an radiography room for radiography in a standing position, the pitch angle calculated based on the distance information from the distance measurement unit 29 is selected. This selects angle information appropriate for the type of radiography task or radiography location, improving user usability. The pitch angle derivation method may also be switched based on the radiography task type or radiography location included in the order information, rather than the roll angle, thereby achieving the same usability as described above. This can be said to switch (select or decide) the calculation method for angle information of the radiography device based on the radiography information (radiography task type or radiography location) of the radiography to be performed. Furthermore, switching based on the radiography information (radiography task type or radiography location) of the radiography to be performed and switching based on the roll angle threshold value may also be combined.

[0086] Furthermore, the pitch angle calculated based on the distance information from the distance measurement unit 29 may be inaccurate when there is a sufficient area (a non-existent region), making it impossible to derive the pitch angle or reducing its accuracy. To address this issue, a method for deriving the pitch angle may be determined based on information about the non-existent region. Specifically, when an imaging region for which a sufficient non-existent region is not or is difficult to secure is selected using information about the imaging region included in the imaging order, the pitch angle calculated based on gravitational acceleration information from the imaging device 1 is always used. When a non-existent region is selected, the pitch angle calculated based on the distance information from the distance measurement unit 29 is always used, or a method for switching between the two derivation methods depending on the roll angle is used. In other words, the calculation method for the angle information of the radiation imaging device is switched (selected or determined) based on the imaging information (imaging region) of the imaging to be performed. Instead of the imaging region information included in the imaging order, imaging region information derived based on the region of the subject (subject S) captured in the optical image data captured by the optical imaging unit (optical camera) 2A may be used.

[0087] Alternatively, instead of using imaging information, optical image data captured by the optical imaging unit (optical camera) 2A is used to detect the missing area, and the result of this detection determines whether a sufficient missing area can be secured. If it is determined that securing a sufficient missing area is difficult, the pitch angle calculated based on gravitational acceleration information from the imaging device 1 is always used. If it is determined that a sufficient missing area can be secured, the pitch angle calculated based on distance information from the distance measurement unit 29 is always used, or a method of switching between the two derivation methods depending on the roll angle is used. Instead of optical image data, depth data from a depth camera may be used to determine whether a sufficient missing area can be secured. Since the illumination surface of the imaging device 1 is captured by the depth camera, the depth data distribution for a missing area is the same as that for a planar object. On the other hand, for a subject, the distribution is different from that for a planar object. Therefore, it is possible to determine a missing area from depth data. Depth data and optical image data may also be combined. This combination improves the accuracy of determining a missing area. In other words, the calculation method for angle information of the radiographic imaging device is switched (selected or determined) based on optical image data and / or depth data from the depth camera.

[0088] In addition, instead of switching between two calculation methods depending on the roll angle (the roll angle after switching of the image capturing device 1), a method may be used in which, for example, the weighting of the angle information of the image capturing device 1 calculated in step S6 and the weighting of the angle information of the image capturing device 1 calculated in step S9 are adjusted depending on the roll angle, and the angle information of the image capturing device 1 relative to the tube 23 is calculated.

[0089] In the above-described switching of the pitch angle derivation method based on the roll angle, the roll angle of the imaging device 1 is used to determine the switching. However, the roll angle of the generator 2 (tube 23) may also be used. Because the imaging device 1 is freely portable, the roll angle changes to various angles, especially while being carried. This causes frequent switching of the derivation method, which can be confusing for the user. On the other hand, the tube 23 is often in a state where the roll angle is 0 degrees when not in use, so the roll angle is stable. Furthermore, even when changing the position of the tube 23 for positioning, the user can easily intuitively imagine the relationship between the operation of the tube 23 and the roll angle. Therefore, by using the roll angle of the generator 2 (tube 23) to determine the switching, the number of switching of the derivation method can be reduced, improving usability. In other words, it can be said that the calculation method for angle information of the radiographic imaging device is switched (selected or determined) based on the gravitational acceleration information from the generator 2.

[0090] Note that both the roll angle of the imaging device 1 and the roll angle of the generator 2 (tube 23) may be used to determine the switching. For example, the switching may be performed as described above when both roll angles reach a threshold value (e.g., 45 degrees) or greater. By using both roll angles, the switching occurs after the positions of both the imaging device 1 and the generator 2 are closer to the target than in conventional methods, which reduces the number of switching operations and improves usability. Different threshold values ​​may be used for each roll angle. This means that the angle information of the radiographic imaging device is calculated based on distance information from the measurement unit (distance measurement unit 29) and / or gravitational acceleration information from the radiographic imaging device (imaging device 1) and / or gravitational acceleration information from the generator 2. It may also be said that the calculation method for the angle information of the radiographic imaging device is switched (selected or determined) based on the gravitational acceleration information from the generator 2 and the gravitational acceleration information from the radiographic imaging device.

[0091] Furthermore, the above-described state determination process may include detecting the inclination of the subject (subject) S, outputting information regarding the inclination of the subject S, and determining whether the subject S is properly positioned based on the detected information regarding the inclination of the subject S and the angle information of the imaging device 1. The result of this determination may then be displayed on the sub-display unit 28, or a warning message (audio) may be output from the audio output unit 33. In such a case, by performing imaging with a marker M attached to the subject S, it is possible to determine the inclination of the subject S from the captured image of the marker M. For example, as shown in FIGS. 17A and 17B, the marker M may have four holes Ma penetrating toward the mounting surface at four positions (top, bottom, left, and right) when viewed from the direction of irradiation with radiation R. Each hole Ma is inclined so as to move away from the center of the marker M as it approaches the mounting surface. Note that while FIGS. 17A and 17B only show cross-sectional views of the marker M in the left-right direction, a cross-sectional view in the up-down direction would be similar.

[0092] When radiation R is irradiated onto the marker M, the radiation R is attenuated as it passes through areas other than the hole Ma, resulting in a lower dose of radiation R reaching the subject S and the imaging device 1. On the other hand, the radiation R is not attenuated at the hole Ma, resulting in a higher dose of radiation R reaching the subject S and the imaging device 1 compared to radiation that has passed through areas other than the hole Ma. Generally, in a radiographic image, areas where radiation R is strongly attenuated appear white, and areas where radiation R is weakly attenuated appear black. Therefore, the areas of the marker M other than the hole Ma appear white, and the hole Ma appears black. When the marker M is positioned so that the mounting surface and the irradiation axis (optical axis) of the radiation R are perpendicular to each other, the holes Ma formed on the left and right sides of the marker M are inclined in opposite directions, but have the same angle of inclination relative to the irradiation axis of the radiation R. Therefore, the widths of the holes Ma (slits) on the left and right sides of the marker M appear equal when viewed from the focal point of the radiation R, as shown in FIG. 17A . On the other hand, when the marker M is positioned such that the mounting surface is tilted with respect to the irradiation axis of the radiation, the angle of inclination of the holes Ma on the left and right sides of the marker M with respect to the irradiation axis differs on the left and right. Therefore, the widths of the holes Ma (slits) on the left and right sides of the marker M when viewed from the focal point of the radiation R appear different on the left and right, as shown in FIG. 17B . Specifically, the hole Ma in the tilted direction of the marker M appears larger. The width of this hole Ma changes in proportion to the angle at which the mounting surface of the marker M is tilted with respect to the irradiation axis. By utilizing this principle, it is possible to calculate the direction and extent to which the marker M is tilted. Therefore, in this way, the tilt direction of the subject S to whom the marker M is attached can be estimated from the tilt direction of the marker M, and the orientation of the subject S can be adjusted to a direction suitable for imaging.

[0093] In the above-described state determination process, the angle information of the image capture device 1 relative to the tube 23 is determined to be within a predetermined reference range based on the angle information calculated by the angle information calculation method selected from the plurality of angle information calculation methods in the angle information preparation process. This method reduces the number of state determination results the user needs to refer to, thereby simplifying the screen configuration and improving usability. However, on the other hand, the calculation method for the angle information of the image capture device 1 relative to the tube 23 (the definition and meaning of the angle information) changes depending on the roll angle of the image capture device 1, which can be confusing for users who are not familiar with the system 100. As a countermeasure, rather than selecting one method from the plurality of angle information calculation methods in the above-described angle information preparation process, it is also possible to calculate angle information using each of the plurality of angle information calculation methods, display all or part of the plurality of angle information, and select the target angle information for state determination using the angle information calculation method selection method described above. Specifically, first, second control unit 211 calculates angle information of imaging device 1 with respect to tube 23 using a first angle information calculation method (step S6; see FIG. 5) and a second angle information calculation method (step S9; see FIG. 5). Then, second control unit 211 displays all or part of the angle information of imaging device 1 with respect to tube 23 calculated using the first angle information calculation method and the second angle information calculation method on a display unit (e.g., sub-display unit 28). Then, second control unit 211 determines whether the roll angle of imaging device 1 (roll angle after switching) is less than 45 degrees. Here, if it is determined that the roll angle of imaging device 1 is less than 45 degrees, second control unit 211 determines whether the angle information of imaging device 1 with respect to tube 23 calculated using the first angle information calculation method is within a predetermined reference range. On the other hand, if it is determined that the roll angle of the photographing device 1 is 45 degrees or more, the second control unit 211 determines whether the angle information of the photographing device 1 relative to the tube 23 calculated by the second angle information calculation method is within a predetermined reference range.Note that the above determination switching is based on the roll angle of the imaging device 1, but may also be based on the roll angle of the generation device 2, based on the imaging technique classification included in the order information, based on optical image data and / or depth data, or based on a combination of two or more of them. That is, it can be said that the method of determining the angle information of the imaging device 1 relative to the tube 23 (angle information to be determined) is switched based on the imaging information of the imaging to be performed. Alternatively, the method of determining the angle information of the imaging device 1 relative to the tube 23 (angle information to be determined) is switched based on the gravitational acceleration information of the imaging device 1 and / or the gravitational angle information of the generating device 2 (tube 23). Alternatively, it can be said that the method of determining the angle information of the imaging device 1 relative to the tube 23 (angle information to be determined) is switched based on the imaging information of the imaging to be performed and the gravitational acceleration information of the imaging device 1 and / or the gravitational angle information of the generating device 2 (tube 23). Alternatively, it can be said that the method of determining the angle information of the imaging device 1 relative to the tube 23 (angle information to be determined) is switched based on the optical image data and / or depth data.

[0094] 3-3-3. Display Control Processing Furthermore, in the angle information preparation process, when the calculation process of step S6 or step S9 is executed, the second control unit 211 executes a display control process, for example, as shown in Fig. 11. The second control unit 211 executes this display control process in parallel with the angle information preparation process.

[0095] When this display control process is started, the second control unit 211 first determines whether or not at least one of the following display start conditions (1) to (5) is satisfied (step S101). (1) The imaging order is selected on the console that commands the start of imaging. (2) The imaging device 1 is removed from the storage location (the storage unit 26 if the system 100 is a medical cart, or a charging cradle if the system 100 is installed in an imaging room). (3) The imaging device 1 is disconnected from the cable. (4) A predetermined button on the collimator 25 provided in the tube 23 (for example, a lamp button for irradiating the range that will be the irradiation field of the radiation R with visible light) is operated. (5) The angle information of the imaging device 1 relative to the tube 23 is within the standard range.

[0096] In step S101, if it is determined that none of the plurality of display start conditions is met (step S101; NO), the second control unit 211 repeats the determination process of step S101 (standby until the display start condition is met). On the other hand, in step S101, if it is determined that at least one of the plurality of display start conditions is met (step S101; YES), the second control unit 211 advances the process to step S102.

[0097] Here, while the position and orientation of the tube 23 are being roughly adjusted, the imaging device 1 is not yet positioned below or behind the subject S, and the angle information may not be useful. Displaying the angle information at such a timing may confuse the user U (for example, adjusting the orientation of the tube 23 to match the angle of the imaging device 1, whose position has not yet been accurately adjusted). However, by the second control unit 211 executing the determination process of step S101, at least one of the main display unit 31 and the sub-display unit 28 displays the angle information after at least one of the plurality of display start conditions is satisfied. This prevents confusion for the user U. Furthermore, while the collimator 25 is irradiating visible light, the positioning operation is in the final stage, and therefore the imaging device 1 is often positioned below or behind the subject S. Therefore, by proceeding to the next process (step S102) when the display start condition (4) is satisfied, useful angle information can be provided to the user U at a more appropriate timing.

[0098] In the determination process of step S101, the display start conditions to be determined as to whether they are met may include the following display start conditions (6) to (8). (6) After the photographing device 1 was removed from the storage section 26 (the tilt began to change), the tilt of the photographing device 1 stabilized again (the photographing device 1 was placed under or behind the subject S and became immobile). (7) The distance (measured value) measured by the distance measuring unit 29 has stabilized (the imaging device 1 has been placed below or behind the subject S and has become stationary). (8) The detection value of the air pressure sensor that detects the air pressure inside the housing of the photographing device 1 provided in the photographing device 1 exceeds the reference value (the photographing device 1 is placed under or behind the subject S and the housing is compressed). (9) The photographing device 1 is captured in the optical image generated by the optical photographing unit 2A.

[0099] By proceeding to the next process (step S102) when the display start condition (6), (7), or (8) is satisfied, the second control unit 211 displays the angle information on the display units 28 and 31 after the image capturing device 1 is placed below or behind the subject S. This prevents confusion for the user U. Furthermore, if the image capturing device 1 appears in the area captured by the optical image capturing unit 2A, it is considered that the image capturing device 1 will be placed below or behind the subject S immediately thereafter. Therefore, by proceeding to the next process when the display start condition (9) is satisfied, the second control unit 211 displays the angle information on the display units 28 and 31 at approximately the same timing as when proceeding to the next process when the display start condition (6), (7), or (8) is satisfied. This prevents confusion for the user U.

[0100] Furthermore, the same display start and end conditions may be used for displaying multiple types of angle information: (i) angle information of the tube 23, (ii) angle information of the imaging device 1, (iii) the difference between (i) and (ii), and (iv) the determination result. Alternatively, all or some of the display start or end conditions may be different for the multiple types of angle information. Specifically, when setting the position of the tube 23 before placing the imaging device 1 behind the subject S, the angle information of the tube 23 alone is useful information. Therefore, for increased convenience, the display of (i) may be started upon the start of the angle information preparation process, and the displays of (ii) to (iv) may be started when any of the display start conditions (1) to (9) are met. Alternatively, the display of (i) may be as described above, and the displays of (ii) and (iii) may be started when the display start condition (1) or (9) is met, and the display of (iv) may be started when the display start condition (4) is met.

[0101] Returning to FIG. 11 , after it is determined in the determination process of step S101 that the display start condition is met, the second control unit 211 executes a display process (step S102). In this display process, the second control unit 211 displays an angle information display screen on at least one of the main display unit 31 and the sub-display unit 28. The angle information display screen displays information based on the angle information of the imaging device 1 relative to the tube 23 calculated in step S6 or step S9 of the angle information preparation process, and an optical image captured by the optical imaging unit 2A, superimposed on the information. Here, the information based on the angle information of the imaging device 1 relative to the tube 23 includes the angle information of the imaging device 1 relative to the tube 23 itself and an imaging device imitation image that imitates the imaging device 1. As described above, the angle information of the imaging device 1 relative to the tube 23 is angle information in the left-right, up-down, and roll directions of the imaging device 1 relative to the irradiation direction of the radiation irradiated from the tube (radiation irradiation unit) 23, i.e., in each of the roll and pitch directions. The imaging device imitation image is an image that simulates the imaging device 1 when viewed with the line of sight aligned with the direction of radiation emitted from the tube 23. When displaying the imaging device imitation image, for example, device size information (information related to the size of the imaging device 1) included in the imaging conditions for radiation imaging may be acquired, and the display size of the imaging device imitation image may be determined according to the device size information. This makes it possible to reflect the size of the imaging device 1 that was actually used when displaying the imaging device imitation image. This makes it easier to imagine the imaging device 1 from the displayed imaging device imitation image.

[0102] 12 to 15 are diagrams showing examples of the angle information display screen. As shown in FIGS. 12 to 15, the angle information display screen G1 has four display areas: a first display area G11, a second display area G12, a third display area G13, and a fourth display area G14. The first display area G11 displays the name of the subject S (patient name). The second display area G12 displays the imaging part and imaging direction, which are imaging conditions for performing radiography. The third display area G13 displays the tube voltage and tube current-time product, which are imaging conditions for performing radiography. The fourth display area G14 displays an optical image G141 (an image of the subject S) captured by the optical imaging unit 2A. The fourth display area G14 also displays angle information G142 and G143 in the left-right and up-down directions of the imaging device 1 relative to the irradiation direction of radiation irradiated from the tube 23, i.e., in the roll and pitch directions, superimposed on the optical image G141. Furthermore, in the fourth display area G14, the above-mentioned photographing device imitation image G144 is displayed in a state where it is superimposed on the above-mentioned optical image G141.

[0103] In the example of FIG. 12, the roll direction angle information G142 and the pitch direction angle information G143 are both "0°." That is, the roll angle (angle information) of the imaging device 1 relative to the horizontal plane and the roll angle (angle information) of the tube 23 relative to the horizontal plane are identical, and the difference between the roll angles of the imaging device 1 and the tube 23 is 0°. Also, the pitch angle (angle information) of the imaging device 1 relative to the horizontal plane and the pitch angle (angle information) of the tube 23 relative to the horizontal plane are identical, and the difference between the pitch angles of the imaging device 1 and the tube 23 is 0°. That is, the example of FIG. 12 shows that the imaging device 1 and the tube 23 are each disposed such that the irradiation axis of the radiation R emitted from the tube 23 is perpendicular to the radiation incident surface 1a of the imaging device 1. Therefore, in the example of FIG. 12, the imaging device imitation image G144 is displayed in a rectangular shape in the fourth display area G14. That is, the imaging device simulating image G144 in the example of FIG. 12 is an image simulating the imaging device 1 when the radiation incident surface 1a is viewed from the front.

[0104] In the example of FIG. 13, the roll direction angle information G142 is "+9°" and the pitch direction angle information G143 is "0°". In other words, the difference in the roll angles between the camera device 1 and the tube 23 is +9°. Also, the difference in the pitch angles between the camera device 1 and the tube 23 is 0°. Therefore, in the example of FIG. 13, the camera device imitation image G144 is displayed in the fourth display area G14 in a state rotated so that its top is in front of the screen and its bottom is in the back of the screen. In other words, the camera device imitation image G144 in the example of FIG. 13 is a trapezoidal image with its top side longer than its bottom side.

[0105] In the example of FIG. 14, the roll direction angle information G142 is "0°" and the pitch direction angle information G143 is "+9°." In other words, the difference in the roll angles between the camera device 1 and the tube 23 is 0°. Also, the difference in the pitch angles between the camera device 1 and the tube 23 is +9°. Therefore, in the example of FIG. 14, the camera imitation image G144 is displayed in the fourth display area G14 rotated so that its right side is in front of the screen and its left side is in the back of the screen. In other words, the camera imitation image G144 in the example of FIG. 14 is a trapezoidal image with the right side longer than the left side.

[0106] In the example of FIG. 15, the roll direction angle information G142 is "+9°" and the pitch direction angle information G143 is "-3°." In other words, the difference in the roll angles between the imaging device 1 and the tube 23 is +9°. Furthermore, the difference in the pitch angles between the imaging device 1 and the tube 23 is -3°. In other words, the example of FIG. 15 shows that the imaging device 1 and the tube 23 are each positioned such that the irradiation axis of the radiation R emitted from the tube 23 is obliquely incident on the radiation incident surface 1a of the imaging device 1. Therefore, in the example of FIG. 15, the imaging device imitation image G144 in the fourth display area G14 is rotated so that its top is in front of the screen, its bottom is in back of the screen, and its left is in front of the screen and its right is in back of the screen. In other words, the imaging device imitation image G144 in the example of FIG. 15 is a rectangular image whose top side is longer than its bottom side and whose left side is longer than its right side.

[0107] When displaying angle information G142, G143 for the roll and pitch directions in the fourth display area G14, the display color of the angle information G142, G143 may be changed depending on the numerical value indicated by the angle information G142, G143. Specifically, when the numerical value indicated by the angle information G142, G143 is within a reference range (e.g., ±3°), the angle information G142, G143 is displayed in black. On the other hand, when the numerical value indicated by the angle information G142, G143 is outside the reference range (e.g., ±3°), the angle information G142, G143 is displayed in red. Similarly, when displaying the camera device imitation image G144 in the fourth display area G14, the display color of the camera device imitation image G144 may be changed depending on the numerical value indicated by the angle information G142, G143. Specifically, if the values ​​indicated by the angle information G142 and G143 are within a reference range (for example, ±3°), the photographing device imitation image G144 is displayed in black. On the other hand, if the values ​​indicated by the angle information G142 and G143 are outside the reference range (for example, ±3°), the photographing device imitation image G144 is displayed in red.

[0108] Furthermore, when displaying angle information G142, G143 for the roll and pitch directions in the fourth display area G14, information for assisting in changing the angle information of the imaging device 1 relative to the tube 23 may be displayed. Specifically, as shown in FIG. 16 , when the value indicated by the angle information G142 is +9°, i.e., when the value indicated by the angle information G142 is not 0°, information G145 for assisting in changing the angle information G142 so that the value indicated by the angle information G142 becomes 0° is displayed. In the example of FIG. 16 , information guiding to rotate the roll angle by 9° in the negative direction is displayed as information G145 for assisting in changing the angle information G142 so that the value indicated by the angle information G142 becomes 0°. Similarly, when the value indicated by the angle information G143 is −3°, i.e., when the value indicated by the angle information G143 is not 0°, information G146 for assisting in changing the angle information G143 so that the value indicated by the angle information G143 becomes 0° is displayed. 16, in order to set the numerical value indicated by the angle information G143 to 0°, information G146 for assisting in changing the angle information G143 displays information guiding to rotate the pitch angle by 3° in the positive direction. Note that when displaying information for assisting in changing the angle information of the imaging device 1 relative to the tube 23, the angle information may not be displayed. Furthermore, the information for assisting in changing the angle information of the imaging device 1 relative to the tube 23 may be displayed when the numerical value indicated by the angle information is outside the reference range. In other words, the information for assisting in changing the angle information of the imaging device 1 relative to the tube 23 may be hidden when the numerical value indicated by the angle information is within the reference range.

[0109] Furthermore, in the fourth display area G14, when the imaging device simulating image G144 is displayed, a simulated image (not shown) of an ideal state may also be displayed. The simulated image of the ideal state is a simulated image that represents how the imaging device 1 appears on the visible light camera screen when ideal positioning is performed based on the imaging conditions included in the imaging order. In such a case, the target SID information included in the imaging conditions and the panel size used for imaging are used to derive how the outer periphery of the imaging device 1 appears on the visible light camera when the imaging device 1 is positioned at the target SID position and the X-ray optical axis intersects perpendicularly with the irradiation surface of the imaging device 1. This derivation may be calculated from the geometric arrangement of the camera, or may be determined by referencing a table of values ​​obtained through prior experiments, or by combining the above calculations and the table. Furthermore, the center of the simulated image of the ideal state is aligned with the center of the camera image. In this case, processing is simplified and can be implemented even with slow processing hardware. The position of the X-ray optical axis at the target SID position may be calculated, and the center of the simulated image may be aligned with that position. Alternatively, the position of the X-ray optical axis at the target SID position may be stored in a table, and the center of the simulated image may be aligned with that position. Depending on the imaging region, the X-ray optical axis and the center of the imaging device 1 may not be aligned. Therefore, information regarding the display position of the simulated image in the ideal state may be stored for each imaging order or each imaging region, and the display position may be determined based on that information. The shape of the simulated image in the ideal state is generally square or rectangular, since oblique imaging is less frequent. If the imaging device 1 used for imaging has a panel with the same aspect ratio (e.g., 17 inches x 17 inches), the shape should be square. If the aspect ratio is different (e.g., 17 inches x 14 inches), the shape should be rectangular. In the latter case, it is easier to use if the optical image captured by the optical imaging unit 2A is used to determine whether the imaging device 1 is currently being used in landscape or portrait orientation, and the orientation of the simulated image in the ideal state is aligned accordingly. The orientation of the image may be recognized as portrait or landscape based on the gravitational acceleration information from the image capture device 1, or may be determined by combining the image with the gravitational acceleration information.In particular, in supine position imaging, it is difficult to determine the orientation using gravitational acceleration information, so combining the two is effective. Furthermore, the simulated image in the ideal state may also correspond to oblique incidence. The oblique incidence angle is obtained from the imaging direction and imaging technique type in the imaging order information, and the circumference of the imaging device 1 when placed at that oblique incidence angle with the target SID is derived by calculation. Alternatively, the circumference can be derived by referring to a table or by combining the above calculation with a table.

[0110] Furthermore, in the fourth display area G14, if the frame of the camera device 1 reflected in the optical image G141 and the frame of the camera device imitation image G144 are misaligned, it is inconvenient to use. Therefore, it is desirable to adjust the display mode of the camera device imitation image G144 so that the outline of the camera device 1 reflected in the optical image G141 and the frame of the camera device imitation image G144 overlap. Specifically, to adjust the display mode of the camera device imitation image G144, for example, the display position and display size of the camera device imitation image G144 are adjusted. More specifically, it is desirable to take the following measures A or B. The size and position of the photographing device 1 on the image are recognized using one or more of the four sides or two or more of the four corners of the photographing device 1 from the optical image G141, and the recognized set of sides or corners (e.g., two sets of corners) is matched with the corresponding sides or corners of the frame of the photographing device imitation image G144 to match the size and position of the photographing device 1 reflected in the optical image G141 (Measure A). It is desirable to adjust both the display size and display position of the frame of the photographing device imitation image G144. However, depending on the user or patient during positioning work, the sides or corners of the photographing device 1 may not be stably displayed in the optical image G141, making it impossible to adjust the display size or display position. In such cases, the photographing device imitation image G144 is displayed at a predetermined display position with a predetermined display size (Measure B). Here, the predetermined display size may be derived by calculation or the like as the size of the panel that appears on the camera when the imaging device 1 is at a standard SID (100 cm or 120 cm) for imaging on a medical cart. The predetermined display position may also be a position where the center of the camera image and the center of the imaging device imitation image G144 are aligned. The display position may also be determined by recognizing the position of the patient's imaging region shown in the camera image based on information about the imaging region to be imaged, and determining the position of the imaging device imitation image G144 based on the recognized position. The selection of either the above-described measure A or measure B may be based on the result of image recognition of the optical image G141 displayed in the fourth display area G14.

[0111] 11, after executing the display process of step S102, the second control unit 211 executes an end determination process (step S103). In this end determination process, the second control unit 211 determines whether or not at least one of the following end conditions (1) to (3) is met. (1) The irradiation instruction switch 22 is operated. (2) Radiation R irradiation has been completed. (3) The angle information preparation process has been completed.

[0112] If it is determined in this termination determination process that the termination condition is not met (step S103; NO), the second control unit 211 returns the process to step S102 and repeats the subsequent processes. That is, the second control unit 211 continues the display process of step S102 until the termination condition is met. On the other hand, if it is determined that the termination condition is met (step S103; YES), the second control unit 211 terminates the display control process.

[0113] [3-3-4. Display control processing and others] In the display control process, the second control unit 211 may execute a confirmation process before starting the determination process of step S101. In this confirmation process, the second control unit 211 determines whether the photographing device 1 has received an instruction to start photographing from the console 3. If there are multiple photographing devices 1 registered in the console 3 (stored in the storage unit 26), the second control unit 211 executes this confirmation process for each photographing device 1. In this case, the second control unit 211 displays, on the display units 28 and 31, the angle information of the photographing device 1 that has received an instruction to start photographing from the console 3 in the display process of the subsequent step S102. Conventionally, multiple photographing devices 1 of different sizes are mounted on a medical cart. Simultaneous display of angle information for multiple unused photographing devices 1 can confuse the user U. However, if the second control unit 211 executes this confirmation process, the user U can easily know which of the multiple photographing devices 1 is currently displaying angle information.

[0114] Furthermore, in the above-described display control process, when the second control unit 211 displays angle information (angle information of the imaging device 1 relative to the tube 23) on the display units 28 and 31 before (during preparation for) imaging the subject S, the second control unit 211 may also display past angle information (angle information of the imaging device 1 relative to the horizontal plane) from a previous imaging session of the subject S on the display units 28 and 31. Specifically, the second control unit 211 retrieves the past angle information based on the ID of the subject S and displays it on the display units 28 and 31. In this case, it is preferable that the second control unit 211 retrieves the past angle information based on the ID of the subject S and the imaging region (chest, abdomen, etc.). This is because the tilt of the imaging device 1 may differ depending on the imaging region. If the tilt of the tube 23 or the subject S changes with each imaging session, the position of the internal structures of the subject S and the density of the radiographic image may differ. This change may cause subtle changes to be overlooked during follow-up observation. However, displaying past angle information improves the reproducibility of positioning, thereby reducing the risk of overlooking small changes. Furthermore, when the angle information display screen is displayed, a past imaging device imitation image (not shown) may be generated from the past angle information and displayed together with the above-mentioned imaging device imitation image G144. By positioning the imaging device imitation image G144 so that it overlaps with the above-mentioned past imaging device imitation image, the user U can easily capture images at the same angle as in the past. It is preferable that the imaging device imitation image G144 and the past imaging device imitation image have different colors and line types. Furthermore, the past imaging device imitation image may be generated as an imitation image of an ideal state. In this generation method, angle information from the past imaging is used as angle information used in the oblique projection correspondence of the imitation image of the ideal state.

[0115] Furthermore, the second control unit 211 may be configured to overlay and display the past angle information and the SID (SSD) on the radiation image. This allows for effective use of limited display space and reduces the need for eye movement between the radiation image and the past angle information, etc., when preparing for imaging or making a diagnosis. Note that, when the imaging currently being prepared is a supine position imaging or an upright position imaging, the second control unit 211 may not display the past angle information on the display units 28, 31. This is because, in supine position imaging and upright position imaging, it is clear that the angle between the horizontal plane and the radiation incident surface 1a is 0° and 90°, respectively, and displaying the past angle information may confuse the user U.

[0116] [3-3-5. Generation of Radiation] Furthermore, upon receiving an operation signal from the irradiation instruction switch 22 (when the irradiation instruction switch 22 is operated), the second control unit 211 transmits an irradiation instruction signal to the generator 213, instructing the generator 213 to generate radiation R in a manner corresponding to the type of radiographic image to be generated (a still image, a dynamic image consisting of multiple frames). Upon receiving the irradiation instruction signal from the second control unit 211, the generator 213 applies a voltage to the tube 23 in accordance with preset imaging conditions and passes a current to the tube 23 in accordance with the imaging conditions. Upon receiving the voltage and current from the generator 213, the tube 23 generates radiation R at a dose corresponding to the applied voltage and the passed current, in a manner corresponding to the applied voltage and the passed current. In the case of a still image, the tube 23 irradiates radiation R only once per depression of the irradiation instruction switch 22. In the case of dynamic images, the tube 23 repeatedly irradiates pulsed radiation R multiple times per predetermined time (for example, 15 times per second) in response to each depression of the irradiation instruction switch 22, or continues irradiating radiation R for a predetermined time.

[0117] [3-3-6. Saving angle information] After generating radiation (taking an image), the second control unit 211 executes a storage process. In this storage process, the second control unit 211 stores angle information (information about the angles of the imaging device 1 and the tube 23 relative to the horizontal plane) used when the subject S was imaged, along with information about the subject S. Methods for storing this angle information include, for example, writing it in the header of the radiographic image, or storing it in the second storage unit 212 or a storage unit of another device (such as a PACS) while linking it to the radiographic image. Note that in this storage process, the second control unit 211 may store not only the angle information but also the SID (SSD) used when the subject S was imaged. In this way, when performing new imaging, it is possible to check the SID used when the subject S was previously imaged, and therefore the position and orientation of the imaging device 1 and the tube 23 can be reproduced with high accuracy when performing new imaging. In particular, if the angle information and the SID are written in the header of the radiographic image (if the radiographic image and the angle information are linked), the angle information can be managed more efficiently. Furthermore, angle information can be made more useful for diagnosis (for example, it can help the diagnostician visualize the proper arrangement of internal structures).

[0118] In addition, when performing imaging that generates multiple radiation images in a single imaging operation (e.g., dynamic imaging (serial imaging)), the second control unit 211 may store angle information (respective angle information of the imaging device 1 and the tube 23 relative to the horizontal plane) at the time of image acquisition for each radiation image (frame) in this storage process. In this manner, the user U or the diagnostician can check whether there was significant body movement during imaging by comparing multiple pieces of angle information. Furthermore, by referring to the angle information, abnormal radiation images can be easily deleted automatically from multiple radiation images or excluded from analysis targets. Furthermore, displaying the angle information along with the radiation images can alert the diagnostician. Furthermore, a graph for each of multiple radiation images (frames) may be displayed, with the horizontal axis representing the time axis and the vertical axis representing the angle information. This allows the position of a frame where the angle has changed to be easily found without frame-by-frame playback. Here, the graph may be displayed in parallel with a playback bar (seek bar). By sliding the cursor on this playback bar and stopping it at a desired position, the frame image corresponding to that position can be displayed. In such cases, it is preferable to align the horizontal axis of the graph with the playback bar. This allows the frame image at the time the angle changed to be displayed by sliding the cursor to the point (time point) where the angle changed, making the display intuitive and easy to use. Furthermore, by preparing an angle determination standard and visually differentiating the portion of the graph corresponding to the frame that exceeds this angle determination standard, the graph becomes easier to understand. Alternatively, a graph may not be displayed, but the portion (time point) of the playback bar corresponding to the frame that exceeds the angle determination standard may be visually different. This eliminates the need for a dedicated display area, resulting in a simpler appearance and improved usability. The angle determination standard may be a threshold value for the angle relative to the tube 23, or the amount or rate of change in the angle over two or more frames, or the gradient or shape (pattern) of the change.When the dynamic radiography (serial radiography) is performed, angle information (respective angle information of the radiography device 1 and the tube 23 relative to the horizontal plane) at the time of image acquisition is determined for each radiographic image (frame). If the angle information has changed by a predetermined value or more, this may be displayed on the display units 28, 31. The determination of the angle information may also be performed by comparing it with angle information obtained when a previous image was acquired (previous radiography). If the angle information obtained for each radiographic image has changed by a predetermined value or more compared to the angle information obtained when the previous radiography was performed, this may be displayed on the display units 28, 31.

[0119] Furthermore, when angle information (respective angle information of the imaging device 1 and the tube 23 relative to the horizontal plane) at the time of image acquisition is stored for each of the multiple radiation images, the second control unit 211 may be configured to execute a determination process in the above-described storage process. In this determination process, the second control unit 211 determines representative angle information representing the imaging based on the multiple angle information stored for each radiation image. The representative angle information for the imaging includes angle information when a predetermined number of multiple radiation images are generated, the average value of all angle information, the median value of all angle information, and the average value of a portion of all angle information (when the first radiation image is generated and the last radiation image are generated). Handling multiple angle information is cumbersome for the user U or the diagnoser. However, in this manner, only the representative angle information can be used as a reference for positioning and diagnosis, thereby reducing the effort required by the user U or the diagnoser. Furthermore, using an average value or the like as the representative angle information allows the representative angle information to be information that more accurately reflects the imaging situation. Furthermore, using an average value, median value, or the like as the representative angle information allows the influence of fluctuations in angle information due to breathing, etc., to be eliminated when using the representative angle information as a reference for positioning and diagnosis.

[0120] [3-3-7. Operation of radiation generating device and other matters] The second control unit 211 according to the above embodiment is configured to display the angle information on the display units 28 and 31 if a display start condition is met while repeatedly executing the calculation process of step S6 or step S9 in the angle information preparation process (see FIG. 5 ). However, the calculation process of step S6 or step S9 of the angle information preparation process may be started when the display start condition is met. This configuration can reduce power consumption of the second control unit 211 compared to when the calculation process of step S6 or step S9 of the angle information preparation process is executed before the display start condition is met. In this case, the second control unit 211 may only store the angle information without displaying it on the display units 28 and 31 after starting the calculation process of step S6 or step S9 of the angle information preparation process. This configuration can check the angle information during maintenance, etc., to determine whether or not there are any abnormalities during image capture.

[0121] When there are multiple medical examination carts of the same type, the tilt angle of the storage unit 26 of each medical examination cart may be slightly different due to individual differences in distortion of the housing of each medical examination cart. Therefore, the second control unit 211 may be configured to correct (perform calibration) the detection value of the first sensor unit 17 received from the imaging device 1 stored in the storage unit 26. Specifically, the second control unit 211 of each medical examination cart corrects the output value so that it indicates that the rotation angle with respect to the horizontal plane when the imaging device 1 is stored in the storage unit 26 is the same tilt angle.

[0122] <4. Effects> As described above, system 100 according to this embodiment includes tube 23 (radiation irradiation unit) that irradiates radiation R. System 100 also includes distance measurement unit (measurement unit) 29 that measures the distance between tube 23 and imaging device 1 that generates an image based on radiation R irradiated from tube 23 and outputs distance information. Based on the distance information measured by distance measurement unit (measurement unit) 29, system 100 calculates angle information of imaging device 1 relative to the irradiation direction of radiation R by tube 23. According to system 100, angle information of imaging device 1 relative to the irradiation direction of radiation R from tube 23 is calculated based on the distance information measured by distance measurement unit 29, so that angle information of imaging device 1 can be appropriately calculated regardless of the orientation of imaging device 1 when it is placed. Therefore, even when radiation R is irradiated horizontally from tube 23, the angle between tube 23 and imaging device 1 can be appropriately adjusted.

[0123] <5.Other> It goes without saying that the present invention is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the present invention.

[0124] For example, in the above description, examples have been disclosed in which a hard disk or a semiconductor nonvolatile memory is used as a computer-readable medium for the program according to the present invention, but the present invention is not limited to these examples. Other computer-readable media include portable recording media such as CD-ROMs. Furthermore, carrier waves are also applicable as a medium for providing data for the program according to the present invention via a communication line. [Explanation of symbols]

[0125] 100 Radiography System (Mobile Phone) 1. Radiography equipment 1a Radiation entrance surface 11 Radiation detection unit 11a Imaging surface 111 Photoelectric conversion panel 111a substrate 111b Charge storage section 111c scan line 111d signal line 12 Scanning driver 13 Readout section 14 First Control Section 15 First memory section 16 First Communications Department 17 First sensor section 2. Radiation generator 21 Generator body 211 Second Control Section 212 Second memory section 213 Generator 214 Second Communications Department 22 Irradiation instruction switch 23 Tube 24 Tube support part 241 First support part 242 Second support part 25 Collimator 26 Storage area 27 Second sensor section 28 Sub display 29 Distance measurement unit 2A Optical imaging unit 3 Console 31 Main display 32 Operation section 33 Audio output section B Bed F focus R Radiation S Subject U User

Claims

1. an optical camera for acquiring an optical image; a display unit that displays an optical image acquired by the optical camera; a radiation irradiation unit that irradiates radiation to a radiation image capturing device that generates a radiation image; an angle information calculation unit that calculates angle information in left, right, up, and down directions of the radiographic image capturing device relative to the radiation irradiation direction of the radiation irradiation unit; a display control unit that displays, on the display unit, predetermined information based on angle information in the left-right and up-down directions of the radiation image capturing device calculated by the angle information calculation unit and the optical image superimposed thereon; A radiography system comprising:

2. 2. The radiation imaging system according to claim 1, wherein the angle information calculation unit compares the horizontal angle and the vertical angle based on the calculated angle information, and switches between the horizontal angle information and the vertical angle information based on a comparison result.

3. The radiation imaging system according to claim 1 , wherein the display control unit changes a display color of the angle information included in the predetermined information displayed on the display unit based on the angle information.

4. The radiation imaging system according to claim 1 , wherein the display control unit changes a display color of an image simulating the radiation imaging device included in the predetermined information displayed on the display unit based on the angle information.

5. 2. The radiation imaging system according to claim 1, wherein the display control unit changes a shape of an outline frame of an image simulating the radiation imaging device included in the predetermined information displayed on the display unit based on the angle information.

6. The radiation imaging system according to claim 1 , wherein the display control unit displays, on the display unit, information for assisting in adjusting the angle of the radiation imaging device in the left-right direction and / or the up-down direction, based on the angle information.

7. 2. The radiation imaging system according to claim 1, further comprising a notification unit that notifies a user when a left-right angle or a up-down angle of the radiation imaging device indicated by the angle information calculated by the angle information calculation unit is changed by a predetermined value or more during radiation imaging by the radiation imaging device.

8. The radiographic imaging by the radiographic imaging device is serial imaging that repeatedly generates frames that constitute a moving image.

8. The radiation imaging system according to claim 7.

9. The radiography system according to claim 1 , wherein the radiography system is a mobile medical cart.

10. the radiation image capturing device is capable of measuring gravitational acceleration using an acceleration sensor provided therein and outputting gravitational acceleration information; a measuring unit that measures the distance between the radiation irradiating unit and the radiation image capturing device and outputs distance information; 2. The radiation imaging system according to claim 1, wherein the angle information calculation unit calculates angle information in left-right and up-down directions of the radiation imaging device based on distance information from the measurement unit and / or gravitational acceleration information from the radiation imaging device.

Images