Radiation detector, radiography system, and tilt angle output method

Abstract

To facilitate angle adjustment of a bulb and a radiation detector.SOLUTION: A detector 1 detects a rotation angle (inclination angle) of the detector 1 with respect to two axes (X axis and Y axis) orthogonal to each other, and outputs inclination information (roll angle and pitch angle). The detector 1 detects an orientation of the detector 1. The detector 1 outputs the inclination information according to the detected orientation of the detector 1.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a radiation detector, a radiation imaging system, and a tilt angle output method.

Background Art

[0002] For example, a mobile radiation imaging system called a mobile X-ray unit may be used to perform radiation imaging of a subject on a hospital bed or the like. In imaging on a bed, the imaging surface of a portable (panel-shaped) radiation detector disposed between the back of the subject and the bed may not necessarily be parallel or perpendicular (tilted) to the horizontal plane. Even in such a case, in order to prevent a density difference from occurring in the radiation image due to the cutoff of the grid attached to the radiation incident surface or the change in the positional relationship of the internal structures of the subject imaged on the radiation detector from affecting the diagnosis, it is necessary to adjust the direction of the tube ball with respect to the radiation detector so that the radiation irradiation axis is perpendicular to the imaging surface of the radiation detector. Therefore, conventionally, various techniques have been proposed to support the adjustment of the direction of the tube ball by the user.

[0003] For example, Patent Document 1 discloses a technique in which a changing unit for changing the direction of a radiation source unit (tube ball) is provided in a radiation irradiation device, and when the changing unit controls the tilt and rotation angle of a monitor based on the direction and rotation angle of a radiation detector, the direction of the radiation source unit is controlled based on the tilt of the radiation detector.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technology disclosed in Patent Document 1, the radiation detector can only align the roll angle / pitch angle of the radiation source (tube) with the roll angle / pitch angle of the radiation detector in one direction. In other words, as shown in Figure 14, the radiation detector defines the roll angle / pitch angle in one direction (for example, upward), so in cases where imaging is performed with the radiation detector rotated 90 degrees to the left from the above-mentioned one direction (see Figure 15(a)) (see Figure 15(b)), the roll angle / pitch angle of the radiation source (tube) and the roll angle / pitch angle of the radiation detector will be reversed, which causes problems in adjusting the angle between the radiation source (tube) and the radiation detector.

[0006] This invention has been made in view of the above problems, and aims to provide a way to easily adjust the angle between the light tube and the radiation detector. [Means for solving the problem]

[0007] To solve the above problems, the radiation detector according to the present invention is A radiation detector that detects radiation that has passed through an object, A rotation angle detection unit detects a first rotation angle of one of the two mutually orthogonal axes of the radiation detector with respect to the horizontal plane, and a second rotation angle of one of the two axes with respect to the horizontal plane, outputs the first rotation angle as first angle information or second angle information, and outputs the second rotation angle as first angle information or second angle information. The device includes a direction detection unit that detects the orientation of the radiation detector in the up, down, left, and right directions, The rotation angle detection unit teeth, The orientation of the radiation detector detected by the orientation detection unit is 、 When it is facing upward, the positive rotation angle of the first rotation angle is output as the first angle information, and the positive rotation angle of the second rotation angle is output as the second angle information. When the direction is downward, the negative rotation angle of the first rotation angle is output as the first angle information, and the negative rotation angle of the second rotation angle is output as the second angle information. In the case of a 90° left direction, the positive rotation angle of the first rotation angle is output as the second angle information, and the negative rotation angle of the second rotation angle is output as the first angle information. death, In the case of a 90° rightward rotation, the negative rotation angle of the first rotation angle is output as the second angle information, and the positive rotation angle of the second rotation angle is output as the first angle information. .

[0008] Furthermore, in order to solve the above problems, the radiography system according to the present invention is A radiation irradiation device that emits radiation, A radiation detector that detects radiation that has passed through the subject, In a radiography system equipped with, A rotation angle detection unit detects a first rotation angle of one of the two mutually orthogonal axes of the radiation detector with respect to the horizontal plane, and a second rotation angle of one of the two axes with respect to the horizontal plane, outputs the first rotation angle as first angle information or second angle information, and outputs the second rotation angle as first angle information or second angle information. The device includes a direction detection unit that detects the orientation of the radiation detector in the up, down, left, and right directions, The rotation angle detection unit teeth, The orientation of the radiation detector detected by the orientation detection unit is 、 When it is facing upward, the positive rotation angle of the first rotation angle is output as the first angle information, and the positive rotation angle of the second rotation angle is output as the second angle information. When the direction is downward, the negative rotation angle of the first rotation angle is output as the first angle information, and the negative rotation angle of the second rotation angle is output as the second angle information. In the case of a 90° left direction, the positive rotation angle of the first rotation angle is output as the second angle information, and the negative rotation angle of the second rotation angle is output as the first angle information. In the case of a 90° rightward rotation, the negative rotation angle of the first rotation angle is output as the second angle information, and the positive rotation angle of the second rotation angle is output as the first angle information. The system includes a display control unit that displays the first angle information and the second angle information output by the rotation angle detection unit on the display unit.

[0009] Furthermore, in order to solve the above problems, the tilt angle output method according to the present invention is A method for outputting the tilt angle of a radiation detector that detects radiation transmitted through a subject, A rotation angle detection step which involves detecting a first rotation angle with respect to the horizontal plane of a first axis of the two mutually orthogonal axes of the radiation detector, detecting a second rotation angle with respect to the horizontal plane of a second axis of the two axes, outputting the first rotation angle as first angle information or second angle information, and outputting the second rotation angle as first angle information or second angle information, The process includes a direction detection step for detecting the orientation of the radiation detector in the up, down, left, and right directions, The aforementioned rotation angle detection step Pu is, The orientation of the aforementioned radiation detector、 When it is facing upward, the positive rotation angle of the first rotation angle is output as the first angle information, and the positive rotation angle of the second rotation angle is output as the second angle information. When the direction is downward, the negative rotation angle of the first rotation angle is output as the first angle information, and the negative rotation angle of the second rotation angle is output as the second angle information. In the case of a 90° left direction, the positive rotation angle of the first rotation angle is output as the second angle information, and the negative rotation angle of the second rotation angle is output as the first angle information. death, In the case of a 90° rightward rotation, the negative rotation angle of the first rotation angle is output as the second angle information, and the positive rotation angle of the second rotation angle is output as the first angle information. 。

Advantages of the Invention

[0010] According to the present invention, the angle adjustment between the line source unit and the radiation detector can be easily performed.

Brief Description of the Drawings

[0011] [Figure 1] It is a side view showing an example of a radiation imaging system according to the present embodiment. [Figure 2] It is a perspective view showing the radiation detector shown by the radiation imaging system of FIG. 1. [Figure 3] It is a block diagram showing the radiation detector shown in FIG. 2. [Figure 4] It is a block diagram showing the radiation generating device and the console included in the radiation imaging system of FIG. 1. [Figure 5] It is a flowchart showing the flow of the tilt information calculation process executed by the radiation detector of FIG. 3. [Figure 6] (a) is a diagram showing the X-axis and Y-axis of the three-axis acceleration sensor provided in the radiation detector, (b) is a diagram showing the inclination of the X-axis of the three-axis acceleration sensor with respect to the horizontal plane, and (c) is a diagram showing the inclination of the Y-axis of the three-axis acceleration sensor with respect to the horizontal plane. [Figure 7] (a) to (d) are diagrams showing the method for determining the orientation of the radiation detector. [Figure 8] (a) to (d) are diagrams for explaining the relationship between the orientation of the radiation detector and roll / pitch. [Figure 9] It is a table showing the relationship between the orientation of the radiation detector and roll / pitch. [Figure 10] It is a diagram showing the arrangement of a conventional radiation detector and the tilt information at that time. [Figure 11]Figure 4 is a flowchart showing the flow of the tilt information preparation process performed by the radiation generator. [Figure 12] Figure 4 is a flowchart showing the flow of the display control processing performed by the radiation generator. [Figure 13] Figure 4 shows an example of a screen displayed by the radiation generator or console. [Figure 14] This image shows the roll / pitch of the radiation detector when it is facing upwards. [Figure 15] This figure shows an example of how the tilt information of the tube and detector is displayed by a conventional radiation generator or console. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to the drawings. However, the technical scope of the present invention is not limited to the following embodiments and illustrated examples.

[0013] <1. Radiography System> First, the general configuration of the radiography system (hereinafter referred to as System 100) according to this embodiment will be explained using the case where System 100 is configured as a mobile medical unit as an example. Figure 1 is a block diagram representing system 100, and Figure 2 is a perspective view showing the radiation detector 1 included in system 100.

[0014] System 100 includes, for example, a radiation detector (hereinafter referred to as detector 1), a radiation generator (hereinafter referred to as generator 2), and a console 3, as shown in Figure 1. Each of the devices 1 to 3 can communicate with each other via a communication network (such as a LAN (Local Area Network), WAN (Wide Area Network), or the Internet).

[0015] Furthermore, system 100 may be capable of communicating with a hospital information system (HIS), a radiology information system (RIS), a picture archiving and communication system (PACS), a dynamic analysis device, etc. (not shown in the diagram). Furthermore, the communication network may be wired or wireless.

[0016] [1-1. Radiation detector] Detector 1 generates a radiation image corresponding to the radiation R received from generator 2. As shown in Figures 1 and 2, the detector 1 according to this embodiment is configured in a panel shape and is portable. Therefore, the detector 1 according to this embodiment can be used not only by being mounted on an imaging table, but also by horizontally positioning the detector 1 between the subject S, who is lying down on the bed B, and the bed B, or, as shown in Figure 1, by vertically positioning the detector 1 between the subject S, who is sitting on a bed B with a portion raised, or a wheelchair, and the backrest.

[0017] The radiation incident surface 1a (the surface facing the subject S) of the detector 1 mounted on the imaging table is parallel or perpendicular to the horizontal plane. However, in imaging without using an imaging table (such as on a bed B or in a wheelchair), the radiation incident surface 1a may not necessarily be parallel or perpendicular to the horizontal plane (it may be tilted). Furthermore, when the detector 1 is interposed between a soft instrument such as the bed B and the subject S, it may move in accordance with the movement of the subject S. Details of this detector 1 will be described later.

[0018] [1-2. Radiation Generators] As shown in Figure 1, the generator 2 comprises a generator body 21, an irradiation instruction switch 22, and a light tube 23. Furthermore, the generator 2 according to this embodiment further comprises a tube support section 24, a collimator 25, and a detector storage section 26. Furthermore, the generator 2 according to this embodiment is movable by wheels provided on the housing. Details of the main unit of the generator 21 will be described later.

[0019] [1-2-1. Irradiation Indicator Switch] The irradiation instruction switch 22 is configured to output an operation signal to the generator main unit 21 when it is operated (pressed) by the user U. Although Figure 1 illustrates a configuration in which the irradiation instruction switch 22 is connected to the generator body 21 by a wire, the irradiation instruction switch 22 and the generator body 21 may be connected wirelessly.

[0020] [1-2-2.Tube] When the irradiation instruction switch 22 is operated, the light tube 23 generates radiation R (e.g., X-rays, etc.) in a manner corresponding to the preset imaging conditions and irradiates from the irradiation port.

[0021] [1-2-3. Tube support part] The tube support section 24 supports the tube 23. The tube support section 24 according to this embodiment includes a first support section 241 extending upward from the main body 21 of the generator, and a second support section 242 extending forward from the upper part of the first support section 241. The tip of the second support section 242 supports the light tube 23. Furthermore, the tube support section 24 has a joint mechanism (not shown) that allows the tube 23 to be moved in the X-axis direction (front-to-back direction of the generator 2 (left-to-right direction in Figure 1)), the Y-axis direction perpendicular to the X-axis (width direction of the generator 2 (direction perpendicular to the plane of the paper in Figure 1)), and the Z-axis direction perpendicular to the X and Y axes (vertical direction (up and down direction in Figure 1)). Furthermore, the tube support section 24, through a joint mechanism (not shown), allows the tube 23 to be rotated around a rotation axis parallel to the X, Y, and Z axes, thereby changing the direction of the radiation port R.

[0022] [1-2-4. Collimator] The collimator 25 is attached to the irradiation port of the tube 23 and is designed to focus the radiation R so that the irradiation field of the radiation R emitted from the irradiation port becomes a predetermined rectangular shape. Furthermore, the collimator 25 is equipped with a lamp button (not shown). Then, when the user operates the lamp button, visible light is emitted into the area that will be the field of radiation R.

[0023] [1-2-5. Detector Storage Unit] The detector storage unit 26 stores the detector 1 when it is not in use. The detector storage unit 26 according to this embodiment is provided on the side of the generator body 21. Furthermore, the detector storage unit 26 according to this embodiment is capable of storing multiple detectors 1. A connector (not shown) is provided inside the detector housing 26, and when the detector 1 is stored, it is connected to the connector 16a of the detector 1.

[0024] [1-3. Console] Console 3 consists of a PC, a mobile device, or a dedicated device. As shown in Figure 1, the console 3 according to this embodiment is mounted on the generator 2. Furthermore, the console 3 can set imaging conditions (tube voltage, tube current and irradiation time or current-time product (mAs value), imaging site, imaging direction, etc.) for at least one of the detector 1 and the generator 2 based on imaging orders obtained from other systems (HIS, RIS, etc.) or operations performed on the control unit 32 by the user U (e.g., a radiologic technologist). Furthermore, Console 3 can acquire image data of the radiation images generated by Detector 1, save it to itself, or transmit it to other devices (PACS, dynamic analysis devices, etc.).

[0025] [1-4. Overview of radiography using radiography systems] Radiography (seated radiography) using the system 100 (mobile medical unit) configured in this way is performed as follows. First, the system 100 is placed near the subject S (next to bed B or wheelchair). Next, have subject S assume a seated position. If subject S is sitting on an adjustable device (such as bed B, which can be partially raised), adjust the angle of the backrest as appropriate. Next, the approximate position and orientation of the light tube 23 are adjusted so that the irradiation port of the light tube 23 faces the area of ​​the subject S that is to be photographed. Next, the detector 1 is removed from the detector storage unit 26 and placed between the subject S's back and the backrest. Next, referring to the tilt information (details described later), the orientation of the tube 23 and the irradiation field are finely adjusted so that the irradiation axis of radiation R is perpendicular to the radiation incident surface 1a. Next, imaging is performed (radiation R is irradiated onto the area to be diagnosed on the subject S, and the detector 1 generates a radiographic image (still image, dynamic image) of the area to be diagnosed). When dynamic images are captured, the image data of the dynamic images is transmitted to a dynamic analysis device as needed to analyze the dynamics of the target area (such as lung ventilation function / blood flow status, joint flexion and extension, etc.).

[0026] [1-5. Radiography Systems and Others] The generator unit 21 and the console 3 may be integrated (or housed in a single enclosure). Furthermore, the generator 2 may be movable by means other than wheels. For example, the generator 2 may be lightweight enough to be carried by a person or mounted on a commercially available trolley, or its bottom surface may be smooth so that it can slide against the floor. Furthermore, in system 100, one of the detector 1 and the generator 2 may be installed in a medical facility's imaging room or the like (the other device may be freely movable).

[0027] <2. Details of the radiation detector> Next, we will describe the details of the detector 1 provided in the system 100 described above. Figure 3 is a block diagram showing the electrical configuration of detector 1.

[0028] [2-1. Specific Configuration of Radiation Detectors] As shown in Figure 3, the detector 1 includes a radiation detection unit 11, a scanning drive unit 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. Parts 11-17 are electrically connected.

[0029] [2-1-1. Sensor section] The radiation detection unit 11 includes a scintillator (not shown) and a photoelectric conversion panel 111.

[0030] Scintillators are formed in a plate-like shape, such as columnar crystals of CsI. Furthermore, when a scintillator receives radiation, it emits electromagnetic waves with a longer wavelength than the radiation (such as visible light) at an intensity corresponding to the dose (mAs) of radiation it received. Furthermore, the scintillators are arranged to spread out parallel to the radiation incidence surface 1a of the housing (see Figure 2).

[0031] The photoelectric conversion panel 111 is positioned parallel to the scintillator and on the side opposite to the surface facing the radiation incident surface 1a in the scintillator. The photoelectric conversion panel 111 includes a substrate 111a and a plurality of charge storage units 111b. Multiple charge storage units 111b are arranged in a two-dimensional (e.g., matrix) manner on the surface of the substrate facing the scintillator, corresponding to each pixel of the radiation image. Each charge storage unit 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 the wiring connected to the readout unit 13. A bias voltage is applied to each semiconductor element from a power supply circuit (not shown). Each charge storage unit is designed to store and release charge, which is read out as a signal value, in response to the radiation received, by switching the on / off state of a switch element.

[0032] [2-1-2. Scanning Drive Unit] The scanning drive unit 12 can switch each switching element to an on state or an off state by applying an on voltage or an off voltage to each scanning line 111c of the radiation detection unit 11.

[0033] [2-1-3. Reading Section] The reading unit 13 reads out the amount of charge flowing in from the charge storage unit 111b via each signal line 111d of the radiation detection unit 11 as a signal value. The reading unit 13 may also be configured to perform binning when reading out signal values.

[0034] [2-1-4. Control Unit] The first control unit 14 includes a CPU (Central Processing Unit) and RAM (Random Access Memory), which are not shown. The CPU then reads various processing programs stored in the first memory unit 15, loads them into RAM, and executes various processes according to these processing programs, thereby comprehensively controlling the operation of each part of the detector 1. Furthermore, the first control unit 14 is configured to generate image data of the radiation image based on the multiple signal values ​​read by the readout unit 13.

[0035] [2-1-5. Storage section] The first storage unit 15 is composed of an HDD (Hard Disk Drive), semiconductor memory, and the like. Furthermore, the first storage unit 15 stores various programs executed by the first control unit 14, as well as parameters and files necessary for program execution. The first memory unit 15 may also be capable of storing image data of radiation images.

[0036] [2-1-6. Communications Department] The first communication unit 16 consists of communication modules and the like. Furthermore, the first communication unit 16 is capable of sending and receiving various signals and data with other devices (such as the generator 2 and console 3) that are connected via a communication network, either by wire or wirelessly.

[0037] [2-1-7. First Sensor Section] The first sensor unit 17 detects the information necessary to calculate the tilt information. The first sensor unit 17 in this embodiment is a 3-axis acceleration sensor. The 3-axis accelerometer detects acceleration acting in the three axes (x-axis, y-axis, and z-axis) as information necessary for calculating tilt information, and transmits it to the first control unit 14. In a stationary state, only gravitational acceleration acts on a 3-axis accelerometer. Therefore, in a stationary state, the 3-axis accelerometer detects the axial components of gravitational acceleration.

[0038] The first sensor unit 17 may also be a 6-axis sensor or a 9-axis sensor. A 6-axis sensor is a 3-axis accelerometer with the added functionality of detecting angular velocity (gyroscope) in each of the three axes. Furthermore, the 9-axis sensor is an enhanced version of the 6-axis sensor, with the added functionality of detecting three directions (east, west, north, and south).

[0039] [2-2. Specific Operation of Radiation Detectors] The first control unit 14 of the detector 1 configured in this way is configured to perform the following operations.

[0040] [2-2-1. Acceleration Detection] For example, the first control unit 14, triggered by the fulfillment of predetermined conditions, causes the first sensor unit 17 to repeatedly detect the three-axis components of gravitational acceleration. The predetermined conditions include, for example, that the power to the detector 1 is turned on, that a predetermined control signal is received from another device (such as the generator 2 or console 3), and that a predetermined operation is performed on the control unit of the detector 1.

[0041] [2-2-2. Radiation Image Generation and Transmission] Furthermore, the first control unit 14 executes control to cause the scanning drive unit 12 to accumulate and release charge in the radiation detection unit 11 in synchronization with the timing of radiation R being irradiated from the generator 2. Furthermore, the first control unit 14 executes control to cause the reading unit 13 to read out the signal value based on the charge emitted by the radiation detection unit 11. Furthermore, the first control unit 14 generates a radiation image corresponding to the dose distribution of the irradiated radiation R based on the signal value read by the readout unit 13. When generating a still image, the radiation image is generated only once for each press of the irradiation instruction switch 22. When generating motion images, the generation of frames constituting the motion image is repeated multiple times per predetermined time (for example, 15 times per second) for each press of the irradiation instruction switch 22. Furthermore, the first control unit 14 transmits the generated radiation image data to other devices (console 3, dynamic analysis device, etc.) via the first communication unit 16.

[0042] [2-3. Radiation Detectors and Others 1] Furthermore, the radiation detection unit 11 of the detector 1 may not include a scintillator, and instead generate an electric charge directly when a semiconductor element receives radiation. Furthermore, the detector 1 may be configured to display the generated dynamic image in real time on a display device connected to it (for example, by viewing through it), rather than converting it into image data.

[0043] [2-4. Radiation Detectors and Others 2] Furthermore, the output value of the first sensor unit 17 (3-axis acceleration sensor) of the detector 1 may show a slight tilt even when the radiation incident surface 1a is parallel to an ideal horizontal plane, due to the effects of the mounting state of the radiation detection unit 11 on the substrate 111a, the mounting state of the radiation detection unit 11 inside the detector 1, and distortion of the housing of the detector 1. Furthermore, if the detector 1 is subjected to impact during transport (for example, by dropping it), the above-mentioned effect of causing the output value to show a slope may newly occur, or the degree of the above-mentioned effect may change. Therefore, the first control unit 14 may be configured to correct (calibrate) the detected value of the first sensor unit 17 that is output to the generator 2. Specifically, the first control unit 14 corrects the output value to indicate that there is no tilt when the detector 1 is placed on an ideal horizontal surface. Alternatively, the first control unit 14 corrects the output value to indicate that the detector 1 is tilted at a known angle when it is stored in a location where the tilt angle with respect to an ideal horizontal plane is known (for example, inside the detector storage unit 26 of the medical vehicle). The first control unit 14 then stores the correction data obtained through the correction process in the first storage unit 15. Correction is performed, for example, when the detector 1 is initially installed, after it has been subjected to an impact, or when no correction data is stored in the first memory unit 15 of the detector 1.

[0044] The first control unit 14 may also be configured to automatically perform correction when it detects that the detector 1 has been stored in the detector storage unit 26. Furthermore, the first control unit 14 may prompt the user U to perform a correction (for example, by displaying text prompting the user). In that case, the first control unit 14 may only prompt for a correction if it determines that the magnitude of the deviation of the calculated first angle information from the specified value of the rotation angle with respect to the horizontal plane when the detector 1 is stored in the detector storage unit 26 exceeds the allowable range.

[0045] <3. Details of the radiation generator and console> Next, we will describe the details of the generator 2 and console 3 included in the system 100 described above.

[0046] [3-1. Specific Configuration of Radiation Generating Devices] In addition to the generator body 21, irradiation instruction switch 22, light tube 23, light tube support section 24, collimator 25, and detector storage section 26, the generator 2 also includes, for example, a second sensor section 27, a sub-display section 28, and a distance measuring section 29, as shown in Figure 4. Furthermore, the generator body 21 of the generator 2 includes a second control unit 211, a second storage unit 212, a generator 213, and a second communication unit 214. Parts 22, 23, 25, 27, 28, and 211-214 are electrically connected by buses or similar means.

[0047] [3-1-1. Second Sensor Section] The second sensor unit 27 in this embodiment is a 3-axis acceleration sensor similar to the first sensor unit 17. The second sensor unit 27 may be a 6-axis sensor or a 9-axis sensor. Furthermore, the sensors constituting the second sensor unit 27 may be of a different type than the sensors constituting the first sensor unit 17.

[0048] [3-1-2. Sub-display section] The sub-display unit 28 is composed of monitors such as LCDs (Liquid Crystal Displays) and CRTs (Cathode Ray Tubes). The sub-display unit 28 displays various images and information according to the instructions of the display signals input from the second control unit 211. The sub-display unit 28 according to this embodiment is provided in the housing of the collimator 25. The sub-display unit 28 may be provided on the housing of the tube 23 or on the tube support unit 24.

[0049] [3-1-3. Distance Measurement Section] The distance measuring unit 29 measures SID or SSD. SID (source image distance) is the distance between the focal point F of the radiation R and the imaging surface 11a of the detector 1 (the surface on which the charge storage unit 111b in the radiation detection unit 11 is provided). Furthermore, SSD (source skin distance) is the distance between the radiation focal point F and the subject's body surface, and is approximately equal to the difference between SID and the subject's body thickness S. The distance measuring unit 29 in this embodiment is provided on the collimator 25.

[0050] The distance measuring unit 29 may consist of, for example, a light-emitting means for emitting laser light, a detection means for detecting reflected laser light, and a calculation means for calculating the distance from the light-emitting means to the reflection point based on the time from when the laser light is emitted until the reflected laser light is detected; or it may consist of an optical camera for photographing the detector 1 in the direction of radiation irradiation, and a calculation means for calculating the SID based on the optical image of the detector 1 generated by the optical camera and the size information of the detector 1; or it may be a combination of these. Since the laser light is reflected off the body surface of the subject S, the distance measured by the distance measuring unit 29 using the laser light is often SSD. In this case, the SID is the measured SSD plus the body thickness of the subject S. Body thickness may be a predetermined standard value, a value entered by the user, or an amount automatically calculated from the subject S's information.

[0051] [3-1-4. Second Control Unit] The second control unit 211 is composed of a CPU, RAM, and the like. The CPU of the second control unit 211 reads various programs stored in the second memory unit 212, expands them into RAM, executes various processes according to the expanded programs, and centrally controls the operation of each part of the generator 2.

[0052] [3-1-5.Second memory section] The second memory unit 212 is composed of non-volatile memory, a hard disk, or the like. Furthermore, the second memory unit 212 stores various programs executed by the second control unit 211, as well as parameters and files necessary for program execution.

[0053] [3-1-6. Generator] Upon receiving a shooting instruction signal from the second control unit 211, the generator 213 applies a voltage to the tube 23 according to the preset shooting conditions and supplies a current to the tube 23 according to the shooting conditions.

[0054] [3-1-7. Second Communications Department] The second communication unit 214 consists of communication modules and the like. Furthermore, the second communication unit 214 is capable of sending and receiving various signals and data with other devices (detector 1, console 3, etc.) that are connected via a communication network, either by wire or wirelessly.

[0055] [3-2. Specific Console Configuration] Console 3 comprises a control unit, a storage unit, a communication unit, a main display unit 31, and an operation unit 32. In this embodiment, the control unit, storage unit, and communication unit of the console 3 are also the second control unit 211, second storage unit 212, and second communication unit 214 of the generator 2, respectively. Console 3 may also include a dedicated control unit, memory unit, and communication unit.

[0056] [3-2-1. Main Display Section] The main display unit 31 is composed of monitors such as LCDs and CRTs. The main display unit 31 then displays various images and information according to the instructions of the display signals input from the second control unit 211.

[0057] [3-2-2. Operation section] The control unit 32 is configured to be operable by the user. The operation unit 32 includes, for example, a keyboard (cursor keys, number input keys, various function keys, etc.), a pointing device (mouse, etc.), and a touch panel laminated on the surface of the main display unit 31. The operation unit 32 then outputs control signals to the second control unit 211 in accordance with the operations performed by the user.

[0058] [3-3. Specific Operation of the Radiography System] The system 100 configured as described above will perform the following operations.

[0059] [3-3-1. Calculation of Slope Information] The first control unit 14 of the detector 1 performs a tilt information calculation process, for example, as shown in Figure 5, when a predetermined condition is met. The predetermined conditions include, for example, that the power to the detector 1 is turned on and that communication with the generator 2 is established.

[0060] When this tilt information calculation process is started, the first control unit 14 first calculates the tilt angle of the detector 1 (step A1). Specifically, the first control unit 14 calculates the tilt angle of the detector 1, as shown in Figure 6(b), the inclination φ of the X-axis (Ax; see Figure 6(a)) of the 3-axis acceleration sensor, which is the first sensor unit 17, with respect to the horizontal plane, using the following equation (1). Also, as shown in Figure 6(c), the first control unit 14 calculates the tilt angle of the detector 1, as shown in Figure 6(c), the inclination θ of the Y-axis (Ay; see Figure 6(a)) of the 3-axis acceleration sensor, which is the first sensor unit 17, with respect to the horizontal plane, using the following equation (2).

number

[0061] Next, the first control unit 14 determines the orientation of the detector 1 from the gravitational acceleration output by the three-axis acceleration sensor (step A2). Specifically, the first control unit 14 determines that the detector 1 is facing upwards when |Ax| ≤ |Ay| and Ay ≥ 0. Here, "facing upwards" means that the detector 1 is positioned vertically and with the △ mark on the detector 1 facing upwards, as shown in Figure 7(a). Furthermore, the first control unit 14 determines that the detector 1 is facing downwards when |Ax| ≤ |Ay| and Ay < 0. Here, "downward" means that the detector 1 is positioned vertically and the △ mark on the detector 1 is facing downwards, as shown in Figure 7(b). Furthermore, the first control unit 14 determines that the orientation of the detector 1 is 90 degrees to the left when |Ax|>|Ay| and Ax>0. Here, 90 degrees to the left means that the detector 1 is positioned horizontally and the △ mark on the detector 1 is facing to the left, as shown in Figure 7(c). Furthermore, the first control unit 14 determines that the orientation of the detector 1 is 90 degrees to the right when |Ax|>|Ay| and Ax≦0. Here, 90 degrees to the right means that the detector 1 is positioned horizontally and the △ mark on the detector 1 is facing to the left, as shown in Figure 7(d).

[0062] When the detector 1 is placed horizontally, the gravitational acceleration of the X and Y axes of the 3-axis accelerometer is close to 0G, making it impossible to correctly determine the orientation of the detector 1. Therefore, when the detector 1 is placed horizontally, its orientation is set to a predetermined direction (upward in this embodiment), and when the tilt (angle of inclination) of either the X or Y axis reaches a certain angle (5 degrees in this embodiment), the first control unit 14 executes the processes of step A2 described above and step A3 described later.

[0063] Next, the first control unit 14 outputs tilt information corresponding to the orientation of the detector 1 determined in step A2 (step A3), and terminates the tilt information calculation process. Specifically, as shown in Figures 8(a) and 9, the first control unit 14 outputs the inclination θ of the Y-axis relative to the horizontal plane calculated in step A1 as the roll angle when the detector 1 is facing upward. The first control unit 14 also outputs the inclination φ of the X-axis relative to the horizontal plane as the pitch angle. Furthermore, as shown in Figures 8(b) and 9, when the detector 1 is facing downwards, the first control unit 14 outputs the inclination of the Y-axis with respect to the horizontal plane calculated in step A1, -θ, as the roll angle. The first control unit 14 also outputs the inclination of the X-axis with respect to the horizontal plane, -φ, as the pitch angle. Furthermore, as shown in Figures 8(c) and 9, the first control unit 14 outputs the inclination φ of the X-axis relative to the horizontal plane calculated in step A1 as the roll angle when the orientation of the detector 1 is 90 degrees to the left. The first control unit 14 also outputs the inclination -θ of the Y-axis relative to the horizontal plane as the pitch angle. Furthermore, as shown in Figures 8(d) and 9, when the detector 1 is oriented 90 degrees to the right, the first control unit 14 outputs the inclination of the X-axis with respect to the horizontal plane calculated in step A1, -φ, as the roll angle. The first control unit 14 also outputs the inclination of the Y-axis with respect to the horizontal plane, θ, as the pitch angle.

[0064] Here, if the detector 1 used is half-size (14 inches x 17 inches), it is usually used in the state shown in Figure 10(a), for example. However, depending on the physique of the subject S, the detector 1 may be rotated 90 degrees (90 degrees to the left) for imaging, for example, as shown in Figure 10(b). Furthermore, because the detector 1 is a simple panel, user U may not be aware of the top and bottom orientation of the detector 1 and may take images with it upside down (rotated 180 degrees), as shown in Figure 10(c) (the resulting radiation image will also be upside down, but it can be rotated later). Therefore, if the detector 1 is used by rotating it as described above, the relationship between the roll angle and the pitch angle will be reversed, or the roll angle or pitch angle will be calculated as a negative value. This may cause problems when attempting to fine-tune the roll angle and pitch angle of the tube 23. Therefore, in step A3, the first control unit 14 outputs tilt information corresponding to the orientation of the detector 1 determined in step A2, thereby preventing the above-mentioned problems from occurring.

[0065] Furthermore, the first control unit 14 may detect whether the detector 1 is facing the illumination surface or a non-illuminated surface based on the information of the gravitational acceleration of the Z axis of the 3-axis accelerometer. If it is facing a non-illuminated surface, it may cancel the process in step A3 described above and draw the user U's attention (by displaying a warning, etc.). Once detector 1 is positioned below or behind the subject S, it is impossible to tell if the detector 1 is upside down until the imaging is complete. However, this method allows for confirmation of whether the detector 1 is upside down even when it is positioned below or behind the subject S, thus preventing imaging failures and unnecessary exposure of the subject S.

[0066] Alternatively, the second control unit 211 may perform the above-mentioned slope information calculation process.

[0067] Furthermore, the second control unit 211 of the generator 2 (console 3) executes tilt information preparation processing, for example, as shown in Figure 11, when predetermined conditions are met. The predetermined conditions include, for example, that the power to the generator 2 is turned on, that communication with the detector 1 is established, and that a predetermined operation is performed on the control unit 32 of the console 3.

[0068] (First verification process) In this tilt information preparation process, the second control unit 211 first performs a verification process (step B1). In this verification process, the second control unit 211 determines the information of the detector 1 that is connected to it (registered in the console 3). Specifically, the second control unit 211 checks whether the detector 1 is equipped with the first sensor unit 17. More specifically, the second control unit 211 determines whether the detector 1 is equipped with the first sensor unit 17 by referring, for example, the presence or absence information of the first sensor unit 17 stored in the detector 1, the detector ID stored in the detector 1, and the presence or absence comparison information of the detector 1 and the first sensor unit 17 stored in other devices (console 3, etc.).

[0069] If, during this verification process, it is determined that the detector 1 does not have the first sensor unit 17 (Step B1; No), the second control unit 211 terminates the tilt information preparation process (does not allow the display of tilt information). On the other hand, if the detector 1 is determined to be equipped with the first sensor unit 17 (Step B1: Yes), the second control unit 211 proceeds to the next process (Step B2) (permits the display of tilt information). By having the second control unit 211 perform this verification process, tilt information will not be displayed when using a detector that does not have the first sensor unit 17, thereby preventing user U from misinterpreting the information. Furthermore, when using the detector 1 equipped with the first sensor unit 17, tilt information is displayed, allowing user U to perform detailed positioning.

[0070] Next, the second control unit 211 acquires tilt information of the detector 1 from the detector 1 (step B2). Specifically, the second control unit 211 acquires tilt information corresponding to the orientation of the detector 1 output in the tilt information calculation process described above (see Figure 5).

[0071] Next, the second control unit 211 calculates the inclination information (roll angle and pitch angle) of the tube 23 with respect to the horizontal plane (step B3). Specifically, the second control unit 211 obtains the three-axis components of the gravitational acceleration detected by the second sensor unit 27 from the second sensor unit 27. Then, the second control unit 211 calculates the inclination information based on the three-axis components of the gravitational acceleration detected by the second sensor unit 27.

[0072] Next, the second control unit 211 executes the termination determination process (step B4). In the termination determination process according to this embodiment, the second control unit 211 determines whether or not at least one of the following multiple termination conditions (1) and (2) has been met. (1) The irradiation instruction switch 22 has been operated. (2) The irradiation of radiation R has been completed. This is because the radiation image generated at the moment radiation R is irradiated is finalized, thus reducing the need to continue tilt information preparation processing and the display control processing described later.

[0073] In this termination determination process, if it is determined that the termination condition is not met (step B4; No), the second control unit 211 returns to the process in step B2. In other words, the second control unit 211 repeats the processes in steps B2 and B3 until the termination condition is met. On the other hand, if it is determined that the termination condition has been met (Step B4; Yes), the second control unit 211 terminates the tilt information preparation process.

[0074] (Preparation and processing of tilt information, etc.) In addition, in the tilt information preparation process described above, the second control unit 211 may execute a state determination process after the processing in step B3. In this state determination process, the second control unit 211 determines whether the difference between the first angle information (tilt information of the detector 1 according to the orientation of the detector 1) and the second angle information (tilt information of the light tube 23) is within a predetermined reference range. In that case, the second control unit 211 may be configured to use the determination result as tilt information. Furthermore, the second control unit 211 may be configured to determine whether the SID measured by the distance measuring unit 29 is within a predetermined reference range.

[0075] Furthermore, if a state determination process is to be performed, the second control unit 211 may determine whether or not motion photography is included in the shooting order before performing the state determination process. Furthermore, if the second control unit 211 determines that motion photography is included in the shooting order, it may change (narrow) the reference range used in the subsequent state determination process. This is because motion photography requires a higher alignment accuracy compared to shooting still images, as it is used for motion analysis.

[0076] Furthermore, if a state determination process is performed, 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 image more susceptible to the effects of oblique radiation (R) (the grid's cutoff effect causes density differences in the radiation image).

[0077] [3-3-2. Display control of tilt information] Furthermore, the second control unit 211, triggered by the start of the repetition of the acquisition process in step B2 and the calculation process in step B3 described above, executes a display control process, for example, as shown in Figure 12. The second control unit 211 executes this display control process in parallel with the tilt information preparation process.

[0078] (Conditional judgment process) In this display control process, the second control unit 211 first executes a condition determination process (step C1). In the condition determination process according to this embodiment, the second control unit 211 determines whether at least one of the following multiple display start conditions (1) to (5) has been met. (1) A shooting order is selected on the console that instructs the start of shooting. (2) The detector 1 is removed from its storage location (the detector storage unit 26 if the system 100 is a mobile medical unit, or the charging cradle, etc., if the system 100 is installed in the imaging room). (3) The detector 1 is disconnected from the cable. (4) A predetermined button on the collimator 25 of the light tube (for example, a lamp button for irradiating visible light into the area that will be the field of radiation R) is operated. (5) The magnitude of the tilt of the detector 1 is within the reference range (for example, the angle difference between the light tube 23 and the detector 1 is smaller than a predetermined angle).

[0079] In this condition determination process, if it is determined that none of the above display start conditions are met (step C1; No), the second control unit 211 repeats this condition determination process (waits until the display start conditions are met). On the other hand, if the condition determination process determines that at least one of the above multiple display start conditions has been met (Step C1; Yes), the second control unit 211 proceeds to the next process (Step C2).

[0080] While the approximate position and orientation of the light tube 23 are being adjusted, the detector 1 may not yet be positioned below or behind the subject S, and therefore the tilt information may not be useful. Displaying tilt information at such a time could confuse the user U (for example, they might adjust the orientation of the light tube 23 to match the angle of the detector 1, which has not yet been precisely adjusted). However, by having the second control unit 211 perform this condition determination process, at least one of the main display unit 31 and the sub-display unit 28 will display the tilt information only after at least one of the above-mentioned display start conditions has been met. This prevents confusion for the user U. Furthermore, while the collimator 25 is irradiating visible light, the positioning process is in its final stages, and therefore the detector 1 is often positioned below or behind the subject S. For this reason, if the system proceeds to the next step (step C2) only when the display start condition (4) is met, useful tilt information can be provided to the user U at a more appropriate timing.

[0081] In addition, the display start conditions (6) to (8) below may be included in the display start conditions used to determine whether or not the condition has been met in this condition determination process. (6) After the detector 1 was removed from the detector storage unit 26 (the tilt began to change), the tilt of the detector 1 stabilized again (the detector 1 was positioned below or behind the subject S and did not move). (7) The pressure sensor of the detector 1, which detects the air pressure inside the housing of the detector 1, has detected a value that exceeds the reference value (the detector 1 is positioned below or behind the subject S and the housing is compressed). (8) The detector 1 was captured in the optical image generated by the optical camera of the distance measuring unit 29.

[0082] By proceeding to the next process (step C2) when display start conditions (6) or (7) are met, the second control unit 211 will display tilt information on the display units 28 and 31 after the detector 1 is positioned below or behind the subject S, thereby preventing confusion for the user U. Furthermore, if the detector 1 is captured in the area photographed by the optical camera of the distance measuring unit 29, it is likely that the detector 1 is positioned below or behind the subject S immediately afterward. Therefore, by setting the system to proceed to the next process when the display start condition (8) is met, the second control unit 211 will display the tilt information on the display units 28 and 31 at approximately the same timing as if the system were set to proceed to the next process when the display start condition (6) or (7) is met, thus preventing confusion for the user U.

[0083] (Display processing) After determining in the condition determination process that the display start condition has been met, the second control unit 211 executes the display process (step C2). In this display process, the second control unit 211 displays the tilt information for the detector 1 acquired in the tilt information preparation process (step B2) and the tilt information for the light tube 23 calculated in the calculation process (step B3) on at least one of the main display unit 31 and the sub-display unit 28. Specifically, as shown in Figure 13, the roll angle (e.g., "+40 degrees") and pitch angle (e.g., "+10 degrees") of the tube 23, as well as the roll angle (e.g., "+40 degrees") and pitch angle (e.g., "+10 degrees") of the detector 1 are displayed on the table T. Here, the display for the detector 1 is based on the tilt information of the detector 1 according to its orientation. For example, even if the orientation of the detector 1 is changed from an upward position (see Figure 15(a)) to a position 90 degrees to the left (see Figure 15(b)), the roll angle and pitch angle values ​​will remain the same. By displaying the tilt information on the sub-display unit 28, the user U can refer to the tilt information on the spot when making fine adjustments to the position and orientation of the light tube 23, making fine adjustments easier. On the other hand, by displaying the tilt information on the main display unit 31, it is possible to perform a final check to see if the positional relationship between the detector 1 and the light tube 23 has changed when operating the irradiation instruction switch 22. The second control unit 211 may also display the roll angle and pitch angle of the detector 1 as the difference between them and the roll angle and pitch angle of the tube 23.

[0084] Furthermore, the second control unit 211 updates the tilt information to be displayed with the new information each time it performs the acquisition process (step B2) and the calculation process (step B3) in the tilt information preparation process. This allows user U to check the tilt information in real time.

[0085] The second control unit 211 may be configured to display the tilt information on the display units 28 and 31 before the above display start conditions are met. In that case, it is desirable that the second control unit 211 changes the display mode of the tilt information as follows. Instead of toggling the display / hide of tilt information, the display color of the tilt information is changed before and after the detector 1 is removed from the detector storage unit 26 (for example, before the detector 1 is removed from the detector storage unit 26, it is displayed in gray (light color), and after it is removed, it is displayed in a darker (normal) color). • Displays tilt information along with a message indicating that detector 1 is stored in detector storage unit 26 or is in sleep mode. This approach prevents confusion for the user U, similar to how tilt information is displayed only after the display start condition is met.

[0086] Furthermore, if the system is configured to proceed to the next process (step C2) when a display start condition other than the above display start condition (4) is met (to display tilt information before the operation of a predetermined button on the collimator 25), the second control unit 211 may change the display mode of the tilt information displayed on the display units 28 and 31 while the collimator 25 is illuminating the area that becomes the illumination field with visible light. Specifically, the tilt information is made easier to see than before illumination by enlarging the display or using pop-up displays.

[0087] Furthermore, if a state determination process is performed in the tilt information preparation process described above, the second control unit 211 may display the determination result on the display units 28 and 31 during the display process. This allows the user U to easily make fine adjustments to the position and orientation of the light tube 23. In this case, the second control unit 211 may display a message only if the opposing state between the light tube 23 and the detector 1 is within the reference range, and not display a message if it is outside the reference range. When the detector 1 is placed below or behind the subject S after roughly adjusting the position and orientation of the light tube 23, the display units 28 and 31 continue to display a message indicating that it is outside the reference range while the position and orientation of the light tube 23 are being roughly adjusted, which can confuse the user U. However, this method prevents such confusion for the user U. Furthermore, the second control unit 211 may set the display units 28 and 31 to display a predetermined color, and when the opposing state between the light tube 23 and the detector 1 enters a reference range, it may change the color displayed on the display units 28 and 31 to another color. Furthermore, the second control unit 211 may be configured to output a predetermined sound to a speaker (not shown) when the opposing state of the light tube 23 and the detector 1 falls within a reference range.

[0088] Furthermore, the second control unit 211 may be configured not to display the determination result on the display units 28 and 31 during periods other than when the collimator 25 is irradiating the area that forms the irradiation field with visible light. During periods when the collimator 25 is not emitting visible light, the detector 1 is often still stored in the detector housing 26 or placed on a desk or the like. However, while the collimator 25 is emitting visible light, the positioning process is in its final stages. This arrangement allows the judgment results to be provided to the user U at a more appropriate time. Furthermore, the control over the display of the judgment results in the state determination process described above can also be applied to the determination result of whether or not the SID (SSD) is within the standard range.

[0089] In the display control process according to this embodiment, the second control unit 211 executes a termination determination process after starting to display the tilt information (step C3). In this termination determination process, the second control unit 211 determines whether or not at least one of the following multiple termination conditions (1) to (3) has been met. (1) The irradiation instruction switch 22 has been operated. (2) The irradiation of radiation R has been completed. (3) The tilt information preparation process has been completed.

[0090] In this termination determination process, if it is determined that the termination condition is not met (step C3; No), the second control unit 211 returns to the process in step C2. That is, the second control unit 211 continues to display the tilt information until the termination condition is met. On the other hand, if it is determined that the termination condition has been met (step C3; Yes), the second control unit 211 terminates the display control process.

[0091] (Display control processing and other 1) Furthermore, before starting the condition determination process in the above display control process, the second control unit 211 may execute a second confirmation process. In this second confirmation process, the second control unit 211 determines whether the detector 1 has received an instruction from the console 3 to start imaging. If there are multiple detectors 1 registered in console 3 (stored in detector storage unit 26), the second control unit 211 performs this second verification process for each detector 1. In this case, the second control unit 211, in subsequent display processing, causes the display units 28 and 31 to display the tilt information of the detector 1, which has received an instruction from the console 3 to start shooting. Conventionally, multiple detectors of different sizes are mounted on the mobile medical unit, but displaying the tilt information of multiple unused detectors 1 simultaneously can confuse the user U. However, if the second control unit 211 performs this second confirmation process, the user U can easily find out which of the multiple detectors 1 is currently displaying its tilt information.

[0092] (Display control processing and other processes 2) Furthermore, in the above-described display control process, when the second control unit 211 displays tilt information on the display units 28 and 31 before photographing the subject S (during preparation), it may also display past tilt information from previous photographs of the subject S on the display units 28 and 31. Specifically, the second control unit 211 retrieves past tilt information based on the subject S's ID and displays it on the display units 28 and 31. In this case, it is desirable that the second control unit 211 retrieves past tilt information based on the subject S's ID and the imaging site (chest, abdomen, etc.). This is because the tilt of the detector 1 may differ depending on the imaging site. If the tilt of the radiograph tube 23 or the subject S changes with each image, it can lead to differences in the arrangement of internal structures in the subject S and the density of the radiographic images. This change can cause subtle changes to be overlooked during follow-up observations. However, displaying past tilt information improves the reproducibility of positioning, thereby reducing the risk of overlooking subtle changes.

[0093] Furthermore, the second control unit 211 may be configured to overlay past tilt information and SID (SSD) onto the radiographic image. This allows for effective use of the limited display space and reduces the need to shift the gaze between the radiographic image and past tilt information when preparing for imaging or performing diagnosis. Furthermore, if the imaging currently being prepared is a supine or standing imaging, the second control unit 211 may be configured not to display past tilt information on the display units 28 and 31. This is because, in supine and standing imaging, the angle φ between the horizontal plane and the radiation incident surface 1a is clearly 0° and 90°, respectively, and displaying this information may actually confuse the user U.

[0094] [3-3-3. Generation of Radiation] Furthermore, upon receiving an operation signal from the irradiation instruction switch 22 (i.e., the irradiation instruction switch 22 has been operated), the second control unit 211 transmits an irradiation instruction signal to the generator 213, instructing it to generate radiation R in a manner corresponding to the form of the radiation image to be generated (still image, dynamic image consisting of multiple frames). Upon receiving an irradiation instruction signal from the second control unit 211, the generator 213 applies a voltage to the tube 23 according to the preset shooting conditions and supplies a current to the tube 23 according to the shooting conditions. The light tube 23, upon receiving voltage and current from the generator 213, generates radiation R in a dose corresponding to the applied voltage and current, in a manner corresponding to the applied voltage and current. In the case of a still image, the light tube 23 irradiates with radiation R only once for each press of the irradiation instruction switch 22. In the case of motion images, the tube 23 repeats pulsed radiation R multiple times per predetermined time (for example, 15 times per second) for each press of the irradiation instruction switch 22, or continues the irradiation of radiation R for a predetermined time.

[0095] [3-3-4. Saving tilt information] After generating (imaging) radiation, the second control unit 211 performs a saving process. In this saving process, the second control unit 211 saves the tilt information of the subject S when it was photographed, along with information about the subject S. Methods for saving tilt information include, for example, writing it to the header of the radiographic image, or storing it in the second memory unit 212 or the memory unit of another device (such as PACS) while linking it to the radiographic image. Furthermore, in this saving process, the second control unit 211 may also save the SID (SSD) from when the subject S was photographed, in addition to the tilt information. In this way, when taking a new photograph, it becomes possible to check the SID from when the subject S was photographed in the past, and thus the position and orientation of the detector 1 and the tube 23 when taking a new photograph can be reproduced with high accuracy. In particular, if tilt information and SID are written to the header of the radiographic image (linking the radiographic image with the tilt information), the tilt information can be managed more efficiently and made more useful for diagnosis (for example, it becomes easier for the diagnostician to visualize the proper arrangement of internal structures).

[0096] Furthermore, if imaging is performed that generates multiple radiographic images in a single shooting operation (for example, motion imaging), the second control unit 211 may be configured to save the tilt information at the time of image acquisition for each radiographic image (frame) during this saving process. In this way, user U and the diagnostician can compare multiple pieces of tilt information to determine whether or not there was significant body movement during the shooting process. Furthermore, by referring to the tilt information, it is easy to automatically delete abnormal radiation images from multiple radiation images or exclude them from analysis. Furthermore, displaying tilt information along with the radiographic image can serve as a warning to the diagnostician.

[0097] Furthermore, if tilt information at the time of image acquisition is saved for each of the multiple radiation images, the second control unit 211 may perform a determination process in the saving process. In this decision process, the second control unit 211 determines representative tilt information that represents the image based on multiple tilt information stored for each radiographic image. "Representative tilt information for imaging" includes, for example, the tilt information when a predetermined number of images (e.g., the first image) is generated from multiple radiographic images, the average value of all tilt information, the median value of all tilt information, and the average value of a portion of all tilt information (e.g., when the first radiographic image is generated and when the last radiographic image is generated).

[0098] Handling multiple tilt data points is cumbersome for both users and diagnosticians. However, this approach allows only representative tilt data to be used as a reference when performing positioning and diagnosis, thus reducing the workload for both users and diagnosticians. Furthermore, by using the average value or similar as representative slope information, this information can more accurately reflect the shooting conditions. Furthermore, by using the mean, median, etc., as representative slope information, the influence of fluctuations in slope information due to respiration, etc., can be eliminated when using it as a reference for positioning or diagnosis.

[0099] [3-3-5. Operation of Radiation Generating Devices and Other Matters 1] In the above embodiment, the second control unit 211 was configured to display the tilt information on the display units 28 and 31 when the display start condition was met while the acquisition process (step B2) and calculation process (step B3) were being repeatedly executed. However, the acquisition process and calculation process may be started only when the display start condition is met. This would reduce the power consumption of the second control unit 211 compared to the case where the acquisition process and calculation process are executed before the display start condition is met. In this case, the second control unit 211 may also be configured to simply save the tilt information without displaying it on the display units 28 and 31 after starting the acquisition and calculation processes. This allows for checking the tilt information during maintenance, etc., to confirm whether there were any abnormalities during shooting.

[0100] [3-3-6. Operation of Radiation Generating Devices and Other Matters 2] If there are multiple mobile medical carts of the same type, the tilt angle of the detector storage section 26 of each mobile medical cart may differ slightly due to individual differences in the distortion of the housing of each cart. Therefore, the second control unit 211 may be configured to correct (calibrate) the detection value of the first sensor unit 17 received from the detector 1 stored in the detector storage unit 26. Specifically, the second control unit 211 of each mobile medical unit corrects the output value to indicate that the rotation angle with respect to the horizontal plane is the same tilt angle for all detectors 1 when they are stored in the detector storage unit 26.

[0101] <4. Effects> As described above, the detector 1 according to this embodiment detects the rotation angle (tilt angle) of the detector 1 with respect to two mutually orthogonal axes (X axis and Y axis) and outputs tilt information (roll angle and pitch angle). The detector 1 also detects the orientation of the detector 1. The detector 1 also outputs tilt information corresponding to the detected orientation of the detector 1. Therefore, the detector 1 outputs tilt information corresponding to the orientation of the detector 1, so that even if the orientation of the detector 1 is changed, the output values ​​of the roll angle and pitch angle do not change. Thus, the angle between the tube 23 and the detector 1 can be easily adjusted regardless of the orientation of the detector 1.

[0102] <5. Others> It goes without saying that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention.

[0103] For example, the above description discloses examples in which a hard disk or semiconductor non-volatile memory is used as a computer-readable medium for the program according to the present invention, but the invention is not limited to these examples. Portable recording media such as CD-ROMs can be used as other computer-readable media. Furthermore, carrier waves can also be used as a medium for providing the data of the program according to the present invention via a communication line. [Explanation of Symbols]

[0104] 100 Radiographic imaging system (mobile medical unit) 1. Radiation detector 1a Radiation entrance surface 11. Radiation detection unit 11a Imaging surface 111 Photoelectric conversion panel 111a substrate 111b Charge storage section 111c scan lines 111d signal line 12 Scanning drive unit 13 Reading section 14 First Control Unit 15 First memory section 16. First Communications Department 17 First Sensor Unit 2. Radiation Generating Devices 21 Generator main unit 211 Second Control Unit 212 Second memory section 213 Generator 214 Second Communications Department 22. Irradiation Indicator Switch 23 Tube 24 Tube support part 241 First support part 242 Second support part 25 Collimator 26 Detector storage unit 27 Second sensor unit 28 Sub-display section 29 Distance measuring unit 3 Console 31 Main display unit 32 Operation section B Bed F focus R: Radiation S: Subject U users

Claims

1. A radiation detector that detects radiation that has passed through an object, A rotation angle detection unit that detects a first rotation angle with respect to the horizontal plane of a first axis of the two mutually orthogonal axes of the radiation detector, and a second rotation angle with respect to the horizontal plane of a second axis of the two axes, outputs the first rotation angle as first angle information or second angle information, and outputs the second rotation angle as first angle information or second angle information, The device includes a direction detection unit that detects the orientation of the radiation detector in the up, down, left, and right directions, The rotation angle detection unit determines that the orientation of the radiation detector detected by the orientation detection unit is When the orientation is upward, the positive rotation angle of the first rotation angle is output as the first angle information, and the positive rotation angle of the second rotation angle is output as the second angle information. When the rotation is downward, the negative rotation angle of the first rotation angle is output as the first angle information, and the negative rotation angle of the second rotation angle is output as the second angle information. In the case of a 90° left direction, the positive rotation angle of the first rotation angle is output as the second angle information, and the negative rotation angle of the second rotation angle is output as the first angle information. death, In the case of a 90° rightward rotation, the negative rotation angle of the first rotation angle is output as the second angle information, and the positive rotation angle of the second rotation angle is output as the first angle information. Radiation detector.

2. The radiation detector according to claim 1, further comprising an output control unit that outputs the first angle information and the second angle information output by the rotation angle detection unit to an external device.

3. The radiation detector according to claim 1 or 2, wherein the first rotation angle and the second rotation angle detected by the rotation angle detection unit, and the orientation detected by the orientation detection unit, are each detected based on the gravitational acceleration output by the three-axis acceleration sensor.

4. The radiation detector according to any one of claims 1 to 3, wherein when predetermined angle information is output by the rotation angle detection unit, the orientation detection unit detects the orientation of the radiation detector.

5. A radiation irradiation device that emits radiation, A radiation detector that detects radiation that has passed through the subject, In a radiography system equipped with, A rotation angle detection unit that detects a first rotation angle with respect to the horizontal plane of a first axis of the two mutually orthogonal axes of the radiation detector, and a second rotation angle with respect to the horizontal plane of a second axis of the two axes, outputs the first rotation angle as first angle information or second angle information, and outputs the second rotation angle as first angle information or second angle information, The device includes a direction detection unit that detects the orientation of the radiation detector in the up, down, left, and right directions, The rotation angle detection unit determines that the orientation of the radiation detector detected by the orientation detection unit is When the orientation is upward, the positive rotation angle of the first rotation angle is output as the first angle information, and the positive rotation angle of the second rotation angle is output as the second angle information. When the rotation is downward, the negative rotation angle of the first rotation angle is output as the first angle information, and the negative rotation angle of the second rotation angle is output as the second angle information. In the case of a 90° left direction, the positive rotation angle of the first rotation angle is output as the second angle information, and the negative rotation angle of the second rotation angle is output as the first angle information. In the case of a 90° rightward rotation, the negative rotation angle of the first rotation angle is output as the second angle information, and the positive rotation angle of the second rotation angle is output as the first angle information. The system includes a display control unit that displays the first angle information and the second angle information output by the rotation angle detection unit on a display unit. Radiography system.

6. The radiation imaging system according to claim 5, wherein the display unit is provided in the radiation irradiation device.

7. The radiography system according to claim 5 or 6, further comprising an adjustment unit capable of adjusting the rotation angle of the radiation source of the radiation irradiation device.

8. A method for outputting the tilt angle of a radiation detector that detects radiation transmitted through a subject, A rotation angle detection step which involves detecting a first rotation angle with respect to the horizontal plane of a first axis of the two mutually orthogonal axes of the radiation detector, detecting a second rotation angle with respect to the horizontal plane of a second axis of the two axes, outputting the first rotation angle as first angle information or second angle information, and outputting the second rotation angle as first angle information or second angle information, The process includes a direction detection step for detecting the orientation of the radiation detector in the up, down, left, and right directions, The rotation angle detection step is performed when the orientation of the radiation detector is When the orientation is upward, the positive rotation angle of the first rotation angle is output as the first angle information, and the positive rotation angle of the second rotation angle is output as the second angle information. When the rotation is downward, the negative rotation angle of the first rotation angle is output as the first angle information, and the negative rotation angle of the second rotation angle is output as the second angle information. In the case of a 90° left direction, the positive rotation angle of the first rotation angle is output as the second angle information, and the negative rotation angle of the second rotation angle is output as the first angle information. death, In the case of a 90° rightward rotation, the negative rotation angle of the first rotation angle is output as the second angle information, and the positive rotation angle of the second rotation angle is output as the first angle information. Tilt angle output method.

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