Radiography System

Abstract

To provide a radiographic system capable of reducing a risk of radiographing which ends in failure, by radiographing while a radiation image detector is inclined about a first axis.SOLUTION: The radiographic system comprises: a radiation source for emitting radiation; an electronic cassette which receives the radiation and detects a radiation image; a portable first holder which holds the electronic cassette; a cord fitted to the first holder; and a camera for imaging the cord. The first holder includes a locking part and a movable part as an inclination change mechanism capable of changing the inclination of the electronic cassette relative to the radiation source. The cord and the camera constitute a first detection mechanism for detecting the inclination of the electronic cassette about an axis X that is an axis toward the radiation source in a case where the radiation detection face of the electronic cassette and the radiation source are arranged facing each other.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The technology of the present disclosure relates to a radiography system. [Background technology]

[0002] Radiography systems have been proposed that are capable of performing radiography not only in limited environments such as medical facilities, but also in special environments such as accident or disaster sites, or camps in conflict zones. For example, Patent Document 1 describes a radiography system that includes a radiation source that emits radiation, a radiological image detector that receives the radiation and detects a radiological image, a tripod that holds the radiation source, and a tripod that holds the radiological image detector.

[0003] The radiography system described in Patent Document 1 is provided with a sensor (referred to as an "orientation sensor," "orientation transceiver," etc. in Patent Document 1) for detecting the relative positions of the radiation source and the radiographic image detector in case the relative positions of the radiation source and the radiographic image detector are displaced when the system is installed in a special environment. In Patent Document 1, the relative positions of the radiation source and the radiographic image detector can be adjusted based on the output of this sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5735725 Summary of the Invention [Problem to be solved by the invention]

[0005] In the radiography system described in Patent Document 1, the relative positions of the radiation source and the radiological image detector are detected by a sensor, but the tilt of the radiological image detector around the first axis is not detected. Here, the first axis is an axis that intersects the vertical axis and is the axis that points toward the radiation source when the radiation detection surface of the radiological image detector and the radiation source are positioned opposite each other.

[0006] In Patent Document 1, as described above, tilt of the radiographic image detector around the first axis is not detected. Therefore, when radiography is performed on a subject whose craniocaudal axis is parallel to the vertical axis with the radiographic image detector tilted around the first axis, a radiographic image of the subject may be detected at an angle, potentially resulting in a failed radiography. In particular, in special environments such as accident or disaster sites, or camping in conflict zones, the installation surface is often uneven, making it easy for the radiographic image detector to tilt around the first axis. Therefore, when radiography is performed with the radiographic image detector tilted around the first axis, there is a high risk of the radiography failing.

[0007] One embodiment of the technology of the present disclosure provides a radiography system that can reduce the risk of radiography failure due to radiography being performed with the radiographic image detector tilted around a first axis. [Means for solving the problem]

[0008] The radiography system of the present disclosure includes a radiation source that emits radiation, a radiological image detector that receives the radiation and detects a radiological image, a portable holder that holds the radiological image detector and includes a tilt change mechanism that can change the tilt of the radiological image detector relative to the radiation source, and a first detection mechanism that detects the tilt of the radiological image detector around a first axis that intersects the vertical axis and is an axis that points toward the radiation source when the radiation detection surface of the radiological image detector is positioned opposite the radiation source.

[0009] It is preferable that a first processor is provided, and the first processor controls the display of the tilt of the radiation image detector around the first axis.

[0010] It is preferable that the first processor calculates, based on the tilt of the radiographic image detector around the first axis, a displacement amount of the tilt changing mechanism for reducing the deviation in the tilt of the radiographic image detector around the first axis, and controls the display to display the calculated displacement amount.

[0011] It is preferable that the first detection mechanism includes a string hanging down in a direction parallel to the vertical axis and a first camera that captures an image of the string, and that the first processor detects the tilt of the radiological image detector around the first axis by analyzing an image captured by the first camera that includes the string.

[0012] The first camera is preferably mounted to the radiation source.

[0013] Preferably, the first detection mechanism includes an acceleration sensor, and the first processor detects the tilt of the radiation image detector around the first axis based on a measurement result of the acceleration sensor.

[0014] It is preferable to provide a second detection mechanism for detecting the tilt of the radiation image detector around at least one of the vertical axis and a second axis intersecting the vertical axis and the first axis.

[0015] It is preferable that a second processor is provided, and the second processor controls the display to display the tilt of the radiation image detector around at least one of the vertical axis and the second axis.

[0016] It is preferable that the second processor calculates the amount of displacement of the tilt change mechanism to reduce the deviation in the tilt of the radiographic image detector around at least one of the vertical axis and the second axis based on the tilt of the radiographic image detector around at least one of the vertical axis and the second axis, and controls the display to display the calculated amount of displacement.

[0017] It is preferable that the second detection mechanism includes at least three markers provided on the radiation image detector or the holder and a second camera that photographs the markers, and that the second processor detects the inclination of the radiation image detector around at least one of the vertical axis and the second axis by analyzing the image photographed by the second camera.

[0018] It is preferable that the second processor, by analyzing the image captured by the second camera, further detects the distance from the point of radiation generation to the detection surface of the radiological image detector, and the position of the radiological image detector relative to the center of radiation irradiation on a plane formed by the vertical axis and the second axis.

[0019] The second camera is preferably mounted to the radiation source.

[0020] The holder preferably includes a holder to which the radiation image detector is attached, and at least three legs that support the holder.

[0021] When the second detection mechanism includes a marker, the marker is preferably provided on the holder.

[0022] The holder preferably includes a fixing mechanism for fixing the positional relationship between the holder and the leg portion. [Effects of the Invention]

[0023] According to the technology of the present disclosure, it is possible to provide a radiography system that can reduce the risk of radiography failure due to radiography being performed with the radiographic image detector tilted around the first axis. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a diagram illustrating a radiography system. [Figure 2] FIG. 2 is a diagram showing an electronic cassette and a first holder. [Figure 3] FIG. 4 is a plan view of the first retainer as viewed from the Z-axis direction. [Figure 4] FIG. 2 is a block diagram showing the internal configuration of the console. [Figure 5] FIG. 2 is a diagram showing an image captured by a camera and a processing unit of a CPU of a console. [Figure 6] 10A and 10B are diagrams illustrating how the tilt of the electronic cassette around the X axis is detected. [Figure 7]10A and 10B are diagrams illustrating how a displacement amount for reducing a deviation in tilt of the electronic cassette around the X axis is calculated. [Figure 8] FIG. 10 is a diagram showing a first notification screen. [Figure 9] 10A and 10B are diagrams illustrating how the tilt of the electronic cassette around the Y axis is detected. [Figure 10] 10A and 10B are diagrams illustrating how the tilt of the electronic cassette around the Z axis is detected. [Figure 11] 10A and 10B are diagrams illustrating how a displacement amount for reducing a deviation in tilt of the electronic cassette around the Y axis is calculated. [Figure 12] FIG. 10 is a diagram showing a second notification screen. [Figure 13] FIG. 10 is a diagram illustrating how an SID is detected. [Figure 14] 10A and 10B are diagrams illustrating how deviation from the irradiation center of the electronic cassette in the Y-axis direction is detected. [Figure 15] FIG. 10 is a diagram showing a third notification screen. [Figure 16] 10 is a flowchart showing a procedure for radiography by the radiography system. [Figure 17] 10 is a flowchart showing a procedure for radiography by the radiography system. [Figure 18] FIG. 10 is a diagram showing a second notification screen on which the displacement amount for reducing the tilt of the electronic cassette around the Z axis is displayed. [Figure 19] FIG. 10 is a diagram showing an example in which a marker is provided on an electronic cassette. [Figure 20] 10 is a diagram showing a second embodiment in which an acceleration sensor is provided as a first detection mechanism. FIG. [Figure 21] FIG. 10 is a diagram illustrating a processing unit of a CPU of a console according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0025] An example of an embodiment of the technology of the present disclosure will be described below with reference to the drawings. Note that the terms "first," "second," etc. used in this specification are used to avoid confusion between components, and do not limit the number of components present in the radiation imaging system.

[0026] [First embodiment] As an example, as shown in FIG. 1, a radiography system 2 is a system that performs radiography of a subject H using radiation R such as X-rays or gamma rays. The radiography system 2 includes an electronic cassette 10, a radiation source 11, a radiation source control device 12, and a console 13. The electronic cassette 10 is held in a portable first holder 14 and is installed on an installation surface 15 at the radiography site via the first holder 14. The radiation source 11 is also held in a portable second holder 16 and is installed on the installation surface 15 at the radiography site via the second holder 16. The radiation source control device 12 is placed directly on the installation surface 15. The radiography site shown in FIG. 1 is an imaging site in a special environment such as the site of an accident or disaster, or a camp in a conflict zone, and the installation surface 15 has unevenness.

[0027] The electronic cassette 10 is a portable radiological image detector that outputs a radiological image corresponding to radiation R transmitted through a subject H. The electronic cassette 10 is disposed so that a detection surface 17 for radiation R faces a radiation source 11. The electronic cassette 10 is communicably connected to a console 13 via wire or wirelessly. The electronic cassette 10 is an example of a "radiological image detector" according to the technology of the present disclosure. In the following, the vertical axis is referred to as the Z-axis, a first axis that intersects the Z-axis and points toward the radiation source 11 when the detection surface 17 of the electronic cassette 10 and the radiation source 11 are disposed opposite each other is referred to as the X-axis, and a second axis that intersects the Z-axis and the X-axis is referred to as the Y-axis. More specifically, the X-axis is a horizontal axis that is perpendicular to the Z-axis, and the Y-axis is a horizontal axis that is perpendicular to the Z-axis and the X-axis. Here, "orthogonal" and "horizontal" refer to orthogonal and horizontal in the sense that they include not only completely orthogonal and horizontal, but also errors that are generally acceptable in the technical field to which the technology of the present disclosure belongs and that do not contradict the spirit of the technology of the present disclosure (for example, an error of about 1% to 10%). Similarly, terms expressing angles such as "30°," which will be described later, also include errors that are generally acceptable in the technical field to which the technology of the present disclosure belongs and that do not contradict the spirit of the technology of the present disclosure (for example, an error of about 1% to 10%).

[0028] The electronic cassette 10 has a detection panel in which a plurality of pixels that accumulate charges corresponding to radiation R are arranged in a two-dimensional matrix. The detection panel is also called an FPD (Flat Panel Detector). The electronic cassette 10 has the function of detecting the start and end of irradiation of radiation R. When the start of irradiation of radiation R is detected, the detection panel starts a storage operation to accumulate charges in the pixels. When the end of irradiation of radiation R is detected, the detection panel starts a readout operation to read out the charges accumulated in the pixels as electrical signals.

[0029] In addition, the electronic cassette 10 and the radiation source control device 12 may be connected so as to be capable of communicating with each other, and synchronization signals indicating the start and end of irradiation of radiation R may be exchanged between the electronic cassette 10 and the radiation source control device 12, thereby synchronizing the timing of the start of irradiation of radiation R and the start of the accumulation operation, and the timing of the end of irradiation of radiation R and the start of the readout operation.

[0030] The console 13 is a tablet terminal carried by an operator OP such as a radiological technologist. The console 13 has a touch panel display 55 (see FIG. 4) that displays various screens and receives operation instructions from the operator OP. The touch panel display 55 is an example of a "display" according to the technology of the present disclosure. The console 13 transmits various signals to the electronic cassette 10. The console 13 also receives radiological images from the electronic cassette 10. The console 13 displays the radiological images on the touch panel display 55. The console 13 may also be a notebook personal computer.

[0031] The console 13 accepts a selection instruction from an operator OP for an imaging menu for radiography. The imaging menu is a combination of imaging regions such as the chest or abdomen, imaging postures such as standing or sitting, and imaging directions such as front, back, or side. The imaging menu is associated with a source to image receptor distance (SID), which is the distance from the source of radiation R to the detection surface 17 of the electronic cassette 10.

[0032] The radiation source 11 has a radiation tube 18 and an irradiation field limiter 19. The radiation tube 18 is provided with a filament, a target, a grid electrode, etc. (all not shown). A voltage is applied between the filament, which is the cathode, and the target, which is the anode. The voltage applied between this filament and the target is called the tube voltage. The filament emits thermoelectrons toward the target in accordance with the applied tube voltage. The target emits radiation R due to the collision of the thermoelectrons from the filament. The grid electrode is disposed between the filament and the target. The grid electrode changes the flow rate of the thermoelectrons from the filament toward the target in accordance with the applied voltage. The flow rate of the thermoelectrons from the filament toward the target is called the tube current. The point at which the radiation R is generated is the point at which the thermoelectrons collide on the target.

[0033] The irradiation field limiter 19 is also called a collimator, and limits the irradiation field of the radiation R emitted from the radiation tube 18. The irradiation field limiter 19 is configured, for example, such that four shielding plates made of lead or the like that block the radiation R are arranged on each side of a rectangle, and a rectangular exit opening that allows the radiation R to pass through is formed in the center. The irradiation field limiter 19 changes the size of the exit opening by changing the positions of the shielding plates, thereby changing the irradiation field of the radiation R. Note that in this example, the radiation source 11 is used as a reference for adjusting the position and attitude, and in order to eliminate the need to adjust the tilt of the radiation source 11 around the Y-axis and the Z-axis, the exit opening of the irradiation field limiter 19 is always set to its maximum size, and the irradiation field of the radiation R is also always set to its maximum size.

[0034] The irradiation field limiter 19 has a built-in camera 20. The camera 20 is a digital camera that captures digital images. The camera 20 is communicably connected to the console 13 via a wired or wireless connection. The camera 20 captures a portion of the electronic cassette 10 and the first holder 14 in response to an image capture command from the console 13. The camera 20 transmits a captured image 75 (see FIG. 5, etc.) of the portion of the electronic cassette 10 and the first holder 14 to the console 13. The position and the like of the camera 20 are adjusted so that a line LC (see FIG. 14) parallel to the Z axis passing through the center (center of the angle of view) of the captured image 75 coincides with a line parallel to the Z axis passing through the irradiation center of the radiation R. The irradiation center of the radiation R is the center of the irradiation field of the radiation R defined by the irradiation field limiter 19. The camera 20 is an example of the "first camera" and "second camera" according to the technology disclosed herein.

[0035] The camera 20 is instructed via the console 13 to capture an image 75 three times in total. The first instruction is given when the electronic cassette 10 and the radiation source 11 are initially placed on the installation surface 15 via the first holder 14 and the second holder 16. The second instruction is given after the tilt error of the electronic cassette 10 around the X axis has been reduced based on the image 75 captured in response to the first instruction. The third instruction is given after the tilt error of the electronic cassette 10 around the Y axis and the Z axis has been reduced based on the image 75 captured in response to the second instruction.

[0036] The radiation source 11 is connected to the radiation source control device 12 by wire. The radiation source control device 12 is also connected to a console 13 by wire or wirelessly so that they can communicate with each other. The radiation source control device 12 controls the operation of the radiation source 11 in response to various operation instructions from the console 13.

[0037] The radiation source control device 12 is configured with radiation R irradiation conditions set by an operator OP via the console 13. The irradiation conditions include the tube voltage and tube current applied to the radiation tube 18, and the radiation R irradiation time. The values ​​of the irradiation conditions are generally determined in advance by the imaging menu. The operator OP also inputs an instruction to start irradiating radiation R to the radiation source control device 12 via the console 13. When an irradiation start instruction is input from the console 13, the radiation source control device 12 irradiates radiation R from the radiation tube 18 under the set irradiation conditions. After starting irradiation of radiation R, the radiation source control device 12 stops irradiating radiation R from the radiation tube 18 when the irradiation time set in the irradiation conditions has elapsed. The irradiation of radiation R may be terminated by an auto exposure control (AEC) function. The AEC function detects the dose of radiation R during irradiation of radiation R, and stops irradiating radiation R from the radiation tube 18 when the integrated value of the detected dose (accumulated dose) reaches a preset target dose. In this case, the detection panel of the electronic cassette 10 starts the readout operation when the cumulative dose of radiation R reaches the target dose. Note that the product of tube current and irradiation time, which is the product of tube current and irradiation time, may also be used as the irradiation condition.

[0038] As an example, as shown in Fig. 2, the first holder 14 is a so-called tripod having a holder 30, a center pole 31, a main body 32, and three legs 33A, 33B, and 33C. The electronic cassette 10 is detachably attached to the holder 30. The first holder 14 is an example of a "holder" according to the technology of the present disclosure. Note that, hereinafter, the legs 33A to 33C may be collectively referred to as legs 33 unless a distinction is particularly required.

[0039] One end of a string 34 is attached to the lower right side of the holder 30. A weight 35 is attached to the other end of the string 34. Due to the action of the weight 35, the string 34 hangs down tightly in a direction parallel to the Z axis. The string 34 may be any material that hangs down tightly in a direction parallel to the Z axis, but it is preferably made of a material that blocks radiation R so that the image of the string 34 can be easily extracted from the captured image 75. For example, the string 34 may be a lead wire or chain several millimeters in diameter and several tens of centimeters in length. The string 34 is provided to detect the tilt of the electronic cassette 10 around the X axis with respect to the radiation source 11. The string 34, together with the camera 20, constitutes a "first detection mechanism" according to the technology disclosed herein.

[0040] Four markers M1, M2, M3, and M4 are provided on the surface of the holder 30 on the side where the detection surface 17 of the electronic cassette 10 is located. Marker M1 is located in the upper left corner, marker M2 in the upper right corner, marker M3 in the lower left corner, and marker M4 in the lower right corner. Like the string 34, the markers M1 to M4 are preferably made of a material that blocks radiation R so that images of the markers M1 to M4 can be easily extracted from the captured image 75. For example, the markers M1 to M4 are circular lead plates with a diameter of several centimeters. The markers M1 to M4 are provided to detect the tilt of the electronic cassette 10 around the Y-axis and the Z-axis relative to the radiation source 11. The markers M1 to M4, together with the camera 20, constitute a "second detection mechanism" according to the technology of the present disclosure.

[0041] The markers M1 to M4 are arranged at positions such that, when there is no deviation in the inclination of the electronic cassette 10 relative to the radiation source 11 around any of the X-axis, Y-axis, and Z-axis, a figure formed by lines connecting the centers of the markers M1 to M4 forms a rectangle. That is, the markers M1 and M2 are provided at the same height with respect to the Z-axis. Similarly, the markers M3 and M4 are provided at the same height with respect to the Z-axis. Furthermore, the markers M1 and M3 are provided at the same horizontal position with respect to the Y-axis. Similarly, the markers M2 and M4 are provided at the same horizontal position with respect to the Y-axis.

[0042] One end of the center pole 31 is connected to the holder 30, and the other end extends downward through the main body 32. Inside the main body 32, the center pole 31 is connected to a handle 36 by a worm gear consisting of a cylindrical worm and worm wheel or a rack and pinion gear, and by rotating the handle 36, the center pole 31 can be moved up and down in the direction of the arrow relative to the main body 32. This up and down movement of the center pole 31 makes it possible to adjust the height position of the holder 30, and ultimately the electronic cassette 10. The center pole 31 is provided with a scale at 1 cm intervals, for example, so that the height position of the electronic cassette 10 can be determined.

[0043] The legs 33A to 33C all have the same configuration, and include, in order from the main body 32 side, a base 37, a locking portion 38, a movable portion 39, and a ferrule 40. The base 37 is connected to the main body 32 at 120° intervals and can be opened and closed relative to the main body 32. The locking portion 38 is a lock nut that loosens when turned counterclockwise and tightens when turned clockwise. When the locking portion 38 is loose, the movable portion 39 can expand and contract relative to the base 37 in the direction of the arrow. The movable portion 39 is provided with a scale at 1 cm intervals, for example, so that the amount of expansion and contraction (displacement) relative to the base 37 can be determined. The ferrule 40 is a portion that directly contacts the installation surface 15. The locking portion 38 and the movable portion 39 are an example of a "tilt change mechanism" according to the technology of the present disclosure. The locking portion 38 may be a lock lever that has two positions: a locked position and an unlocked position.

[0044] 3, the main body 32 is provided with a fixing mechanism 45 that fixes the positional relationship between the holder 30 and the legs 33. The fixing mechanism 45 is a click-stop mechanism that includes a holding portion 46 that holds the center pole 31 therein so that it can move up and down, a click ball 47 that can be protruded and retracted from the holding portion 46, and a rotating portion 48 that rotates around the holding portion 46 with the center pole 31 as its axis. By rotating the rotating portion 48, the positions of the legs 33A to 33C can be changed. The main body 32 is provided with a scale at 1° intervals, for example, so that it is possible to know how many degrees it has been rotated from the original position.

[0045] Grooves 49 into which the click balls 47 fit are formed at 120° intervals in the rotating portion 48. In the case of Fig. 3, which shows a plan view of the first holder 14 with the electronic cassette 10 attached from the Z-axis direction, the grooves 49 are formed at positions where one of the legs 33A to 33C (in Fig. 3, this may be any one of the legs 33C, 33A, and 33B) intersects at right angles with the detection surface 17 of the electronic cassette 10. 3, in which the first holder 14 with the electronic cassette 10 attached thereto is viewed from the Z-axis direction, the grooves 49 are formed at positions such that two adjacent legs 33 (which may be any of legs 33A and 33B, legs 33B and 33C, or legs 33C and 33A in FIG. 3) other than the leg 33 positioned perpendicular to the detection surface 17 of the electronic cassette 10 extend in directions symmetrical with respect to the detection surface 17 of the electronic cassette 10, specifically, in directions forming an angle of 30°. By forming the grooves 49 at such positions, the positional relationship between the holder 30 and the legs 33A to 33C is always fixed in the above-mentioned state. Note that the second holder 16 has the same basic configuration as the first holder 14, except that the object held by the second holder 16 is changed from the electronic cassette 10 to the radiation source 11, and therefore a description thereof will be omitted.

[0046] 4, the console 13 includes, in addition to the above-mentioned touch panel display 55, storage 56, memory 57, a CPU (Central Processing Unit) 58, and a communication I / F (Interface) 59. The touch panel display 55, storage 56, memory 57, CPU 58, and communication I / F 59 are interconnected via a bus line (not shown).

[0047] The storage 56 is a hard disk drive that is built into the computer that constitutes the console 13 or that is connected via a cable or network. The storage 56 stores control programs such as an operating system, various application programs such as an operating program 60, and various data associated with these programs. The operating program 60 is an application program that causes the computer to function as the console 13. Note that a solid state drive may be used instead of a hard disk drive.

[0048] The memory 57 is a work memory for the CPU 58 to execute processing. The CPU 58 loads programs stored in the storage 56 into the memory 57 and executes processing according to the programs. In this way, the CPU 58 comprehensively controls each part of the computer. The CPU 58 is an example of the "first processor" and "second processor" according to the technology of the present disclosure. The memory 57 may be built into the CPU 58. The communication I / F 59 controls the transmission of various information to and from external devices such as the electronic cassette 10, the radiation source control device 12, and the camera 20.

[0049] As an example, as shown in FIG. 5, when the operating program 60 is started, the CPU 58 of the computer constituting the console 13 functions as an image analysis unit 70, a displacement amount calculation unit 71, and a display control unit 72 in cooperation with the memory 57, etc.

[0050] A captured image 75 from the camera 20 is input to the image analysis unit 70. The captured image 75 shows the bottom of the electronic cassette 10, the holder 30, the string 34, and the like. The image analysis unit 70 analyzes the captured image 75 to detect the tilt of the electronic cassette 10 around the X-axis, Y-axis, and Z-axis. The image analysis unit 70 also analyzes the captured image 75 to detect the position of the electronic cassette 10 relative to the irradiation center of the radiation R on the YZ plane formed by the SID, the Y-axis, and the Z-axis (hereinafter abbreviated as the position relative to the irradiation center). The image analysis unit 70 outputs the detected tilt of the electronic cassette 10, etc., as an analysis result 76 to the displacement amount calculation unit 71 and the display control unit 72.

[0051] The displacement amount calculation unit 71 calculates the displacement amount of the movable unit 39 for reducing the deviation in the tilt of the electronic cassette 10 around the X-axis based on the tilt of the electronic cassette 10 around the X-axis in the analysis result 76. The displacement amount calculation unit 71 also calculates the displacement amount of the movable unit 39 for reducing the deviation in the tilt of the electronic cassette 10 around the Y-axis based on the tilt of the electronic cassette 10 around the Y-axis in the analysis result 76. The displacement amount calculation unit 71 outputs the displacement amount calculation result 77 to the display control unit 72. Here, the displacement amount of the movable unit 39 for reducing the deviation in the tilt of the electronic cassette 10 is, for example, the displacement amount for eliminating the deviation. The displacement amount for eliminating the deviation may not only be the displacement amount that completely eliminates the deviation, but may also include an error that is generally acceptable in the technical field to which the technology of the present disclosure belongs and that does not contradict the spirit of the technology of the present disclosure (for example, an error of about 1% to 10%). Alternatively, the displacement amount of the movable portion 39 for reducing the deviation of the tilt of the electronic cassette 10 may be the displacement amount that makes the deviation less than a preset threshold value.

[0052] The display control unit 72 controls the display of various screens on the touch panel display 55. For example, the display control unit 72 controls the display of a first notification screen 90 (see FIG. 8 ) on the touch panel display 55, which includes the tilt of the electronic cassette 10 around the X axis and the displacement amount of the movable unit 39 for reducing the deviation in the tilt of the electronic cassette 10 around the X axis. The display control unit 72 also controls the display of a second notification screen 115 (see FIG. 12 ) on the touch panel display 55, which includes the tilt of the electronic cassette 10 around the Y axis and the Z axis, and the displacement amount of the movable unit 39 for reducing the deviation in the tilt of the electronic cassette 10 around the Y axis. Furthermore, the display control unit 72 controls the display of a third notification screen 125 (see FIG. 15 ) on the touch panel display 55, which includes the SID and its position relative to the irradiation center.

[0053] As an example, as shown as analysis image 80_1 in FIG. 6, the image analysis unit 70 uses well-known image recognition technology to extract images of markers M3 and M4 and the string 34 from captured image 75_1 captured in response to the first capture instruction. The image analysis unit 70 calculates the angle between line L_M34 connecting the centers of markers M3 and M4 and line LS tracing the string 34. The image analysis unit 70 then detects the angle obtained by subtracting 90° from the calculated angle as the tilt α of the electronic cassette 10 around the X axis. If the angle between line L_M34 and line LS is less than 90° (acute angle), as shown in the figure, α takes a negative value. Conversely, if the angle between line L_M34 and line LS is greater than 90° (obtuse angle), α takes a positive value. When the angle between line L_M34 and line LS is 90°, α = 0°, which means that there is no deviation in the tilt of the electronic cassette 10 around the X axis. The image analysis unit 70 outputs the detected tilt α of the electronic cassette 10 around the X axis as the analysis result 76_1 to the displacement amount calculation unit 71, etc. Figure 6 illustrates an example where the angle between line L_M34 and line LS is 80°, and α = 80° - 90° = -10°.

[0054] 7 , the displacement amount calculation unit 71 refers to a displacement amount calculation table 85 to calculate a displacement amount for reducing the deviation in the tilt of the electronic cassette 10 around the X axis. The displacement amount calculation table 85 is stored in the storage 56. The displacement amount calculation table 85 registers the displacement amount of the movable part 39 for each tilt α of the electronic cassette 10 around the X axis. The displacement amount calculation unit 71 reads out from the displacement amount calculation table 85 the displacement amount corresponding to the tilt α of the electronic cassette 10 around the X axis, which is included in the analysis result 76_1 from the image analysis unit 70, and outputs the read displacement amount to the display control unit 72 as a displacement amount calculation result 77_1.

[0055] Here, of the two legs 33 extending in directions symmetrical with respect to the detection surface 17 of the electronic cassette 10, specifically in directions forming an angle of 30°, the leg 33 located on the left side of the subject H is referred to as the left front leg 33, the leg 33 located on the right side of the subject H is referred to as the right front leg 33, and the leg 33 located at a position perpendicular to the detection surface 17 of the electronic cassette 10 is referred to as the rear leg 33. In this case, even if the movable part 39 of the rear leg 33 is displaced, the tilt of the electronic cassette 10 around the X axis does not change. For this reason, the displacement amounts of the movable parts 39 of the right front and left front legs 33 are registered in the displacement amount calculation table 85, but the displacement amount of the movable part 39 of the rear leg 33 is not registered. 7 illustrates an example in which the tilt α of the electronic cassette 10 around the X axis included in the analysis result 76_1 is −10°, and a displacement calculation result 77_1 is calculated to set the movable part 39 of the left front leg 33 to +8 cm and the movable part 39 of the right front leg 33 to −2 cm. Note that, since the tilt of the electronic cassette 10 around the X axis changes when the movable part 39 of one of the right front and left front legs 33 is displaced, only the displacement amount of the movable part 39 of one of the right front and left front legs 33 may be registered in the displacement calculation table 85.

[0056] 8, a first notification screen 90 displayed on the touch panel display 55 after the first imaging instruction has been issued includes an illustration display area 91, a result display area 92, and a guide display area 93. The illustration display area 91 displays an illustration of the first holder 14 with the electronic cassette 10 attached and the subject H viewed from the Z axis direction in a plan view, and an illustration of the electronic cassette 10 and holder 30 viewed from the X axis direction in a plan view. The illustration of the first holder 14 with the electronic cassette 10 attached and the subject H viewed from the Z axis direction displays the words "left front," "right front," and "rear" to distinguish between the legs 33A to 33C.

[0057] The result display area 92 displays the analysis result 76_1 and the displacement amount calculation result 77_1. More specifically, the result display area 92 displays the tilt α of the electronic cassette 10 around the X axis and the displacement amount of the movable part 39 for reducing the deviation in the tilt of the electronic cassette 10 around the X axis. The guide display area 93 displays a guide showing how to adjust the length of the movable part 39. Note that if α=0°, the displacement amount calculation result 77_1 is not displayed in the result display area 92, and instead a message is displayed indicating that adjustment of the length of the movable part 39 is not necessary.

[0058] Note that there may be a deviation in the tilt of the radiation source 11 around the X-axis, and the line LS tracing the string 34 may not be parallel to the left and right sides of the analysis image 80_1. In that case, the angle between the line LS tracing the string 34 and the left and right sides of the analysis image 80_1 is calculated as the tilt of the radiation source 11 around the X-axis, and the amount of displacement of the movable part of the second holder 16 required to reduce the tilt of the radiation source 11 around the X-axis is further calculated. The tilt of the radiation source 11 around the X-axis and the amount of displacement of the movable part of the second holder 16 required to reduce the tilt of the radiation source 11 around the X-axis are then displayed on the first notification screen 90 to prompt the operator OP to adjust the length of the movable part of the second holder 16.

[0059] An OK button 94 is provided at the bottom of the first notification screen 90. The operator OP displaces the movable part 39 using the scale as a guide in accordance with the display in the result display area 92, and then selects the OK button 94. When the OK button 94 is selected, an instruction to perform a second imaging is issued. Note that if the tilt deviation of the electronic cassette 10 around the X axis has not yet been sufficiently reduced when the OK button 94 is selected, an instruction to perform a second imaging is not issued, and the operator OP is prompted to adjust the length of the movable part 39 again. Here, a case where the tilt deviation of the electronic cassette 10 around the X axis has not been sufficiently reduced refers to a case where the tilt α of the electronic cassette 10 around the X axis is not 0° or is not within a preset tolerance range (such as -1°<α<+1°) centered around 0°.

[0060] As an example, as shown as analysis image 80_2 in FIG. 9 , the image analysis unit 70 extracts images of markers M1 to M4 from captured image 75_2 captured in response to the second capture instruction using well-known image recognition technology. The image analysis unit 70 calculates the length of line L_M12 connecting the centers of markers M1 and M2 and the length of line L_M34 connecting the centers of markers M3 and M4. Then, from the ratio L_M12 / L_M34 of the length of line L_M12 to the length of line L_M34, the tilt β of the electronic cassette 10 around the Y axis is calculated using equation 100, which calculates the tilt β of the electronic cassette 10 around the Y axis. Equation 100 is an equation with the ratio L_M12 / L_M34 as a variable and β as a solution, and is stored in the storage 56. If the electronic cassette 10 is tilted backward as shown in the figure, the length of line L_M12 will be shorter than the length of line L_M34, and the ratio L_M12 / L_M34 will be smaller than 1. In this case, β will be a negative value. Conversely, if the electronic cassette 10 is tilted forward, the length of line L_M12 will be longer than the length of line L_M34, and the ratio L_M12 / L_M34 will be larger than 1. In this case, β will be a positive value. If the detection surface 17 of the electronic cassette 10 is parallel to the Z axis, the lengths of line L_M12 and line L_M34 will be the same, and the ratio L_M12 / L_M34 will be 1. In this case, β = 0°, meaning that there is no deviation in the tilt of the electronic cassette 10 around the Y axis. The image analysis unit 70 outputs the calculated β as the analysis result 76_2A to the displacement amount calculation unit 71, etc.

[0061] 10, the image analysis unit 70 calculates the length of a line L_M13 connecting the centers of markers M1 and M3 and the length of a line L_M24 connecting the centers of markers M2 and M4 in an analysis image 80_2 of a captured image 75_2 captured in response to a second capture command. Then, using equation 105, which calculates the tilt γ of the electronic cassette 10 around the Z axis, from the ratio L_M13 / L_M24 of the lengths of lines L_M13 and L_M24, the tilt γ of the electronic cassette 10 around the Z axis is calculated. Equation 105 is an equation with the ratio L_M13 / L_M24 as a variable and γ as a solution, and is stored in the storage 56. If the electronic cassette 10 were tilted to the left as shown in the figure, the length of line L_M13 would be longer than the length of line L_M24, and the ratio L_M13 / L_M24 would be greater than 1. In this case, γ takes a negative value. Conversely, if the electronic cassette 10 is tilted to the right, the length of line L_M13 will be shorter than the length of line L_M24, and the ratio L_M13 / L_M24 will be smaller than 1. In this case, γ takes a positive value. If the detection surface 17 of the electronic cassette 10 is parallel to the Y axis, the lengths of line L_M13 and line L_M24 will be the same, and the ratio L_M13 / L_M24 will be 1. In this case, γ=0°, meaning that there is no deviation in the tilt of the electronic cassette 10 around the Z axis. The image analysis unit 70 outputs the calculated γ as the analysis result 76_2B to the displacement amount calculation unit 71, etc. For convenience, the process shown in Figure 9 for calculating the tilt β of the electronic cassette 10 around the Y axis and the process shown in Figure 10 for calculating the tilt γ of the electronic cassette 10 around the Z axis have been described separately, but the image analysis unit 70 performs the processes of Figures 9 and 10 in parallel.

[0062] 11 , the displacement amount calculation unit 71 refers to a displacement amount calculation table 110 to calculate a displacement amount for reducing the deviation in the tilt of the electronic cassette 10 around the Y axis. The displacement amount calculation table 110 is stored in the storage 56. The displacement amount calculation table 110 registers the displacement amount of the movable part 39 for each tilt β of the electronic cassette 10 around the Y axis. The displacement amount calculation unit 71 reads out from the displacement amount calculation table 110 the displacement amount corresponding to the tilt β of the electronic cassette 10 around the Y axis, which is included in the analysis result 76_2A from the image analysis unit 70, and outputs the read displacement amount to the display control unit 72 as a displacement amount calculation result 77_2A.

[0063] When changing the tilt of the electronic cassette 10 around the Y axis, it takes less time to adjust by displacing only the movable part 39 of the rear leg 33 than by displacing both the movable parts 39 of the right front and left front legs 33 by the same amount. For this reason, the displacement amounts of the movable parts 39 of the right front and left front legs 33 are not registered in the displacement amount calculation table 110, and only the displacement amount of the movable part 39 of the rear leg 33 is registered. Figure 11 illustrates an example in which the tilt β of the electronic cassette 10 around the Y axis included in the analysis result 76_2A is -10°, and a displacement amount calculation result 77_2A is calculated to change the movable part 39 of the rear leg 33 by +10 cm.

[0064] The tilt deviation of the electronic cassette 10 around the Z axis cannot be reduced by displacing the movable part 39. For this reason, the tilt deviation of the electronic cassette 10 around the Z axis is reduced by rotating the electronic cassette 10 around the Z axis together with the first holder 14.

[0065] 12, a second notification screen 115 displayed on the touch panel display 55 after a second imaging instruction has the same illustration display area 91 and guide display area 93 as the first notification screen 90, as well as result display areas 116A and 116B. The result display area 116A displays an analysis result 76_2A and a displacement amount calculation result 77_2A. More specifically, the result display area 116A displays the tilt β of the electronic cassette 10 around the Y axis and the displacement amount of the movable unit 39 required to reduce the tilt of the electronic cassette 10 around the Y axis. Note that if β=0°, the result display area 116A does not display the displacement amount calculation result 77_2A, and instead displays a message indicating that the length of the movable unit 39 does not need to be adjusted.

[0066] The result display area 116B displays the analysis result 76_2B, more specifically, the tilt γ of the electronic cassette 10 around the Z axis. The result display area 116B also displays the rotation direction and amount of rotation of the first holder 14 required to reduce the deviation in tilt of the electronic cassette 10 around the Z axis, which are derived from the analysis result 76_2B. Note that if γ=0°, the rotation direction and amount of rotation of the first holder 14 are not displayed, and instead a message is displayed indicating that adjustment of the orientation of the first holder 14 is not necessary.

[0067] An OK button 117 is provided at the bottom of the second notification screen 115. The operator OP displaces the movable part 39 or the first holder 14 using the scales in accordance with the displays in the result display areas 116A and 116B, and then selects the OK button 117. When the OK button 117 is selected, an instruction to take a third photograph is issued. Note that if the tilt deviation of the electronic cassette 10 around the Y axis and / or the Z axis has not yet been sufficiently reduced when the OK button 117 is selected, the instruction to take a third photograph is not issued, and the operator OP is prompted again to adjust the length of the movable part 39, etc. Here, a case where the tilt deviation of the electronic cassette 10 around the Y axis and / or the Z axis has not been sufficiently reduced means a case where the tilt β and / or γ of the electronic cassette 10 around the Y axis and / or the Z axis is not 0°, or is not within a predetermined tolerance range centered on 0° (-1°<β<+1°, -1°<γ<+1°, etc.).

[0068] As an example, as shown as analysis image 80_3 in Fig. 13, the image analysis unit 70 uses well-known image recognition technology to extract images of markers M1 to M4 from captured image 75_3 captured in response to the third shooting instruction. The image analysis unit 70 calculates the area S of a rectangle surrounded by lines connecting the centers of markers M1 to M4. Note that the image recognition technology used by the image analysis unit 70 to extract images of markers M1 to M4 and string 34 from analysis image 80 also includes technology such as semantic segmentation using a machine learning model that uses a convolutional neural network.

[0069] The image analysis unit 70 calculates the SID from the area S by referring to the SID calculation table 120. The SID is registered in the SID calculation table 120 for each area S. The SID calculation table 120 is stored in the storage 56. When the area S is small, the SID is relatively long, and when the area S is large, the SID is relatively short. The image analysis unit 70 outputs the calculated SID to the display control unit 72 as the analysis result 76_3A. FIG. 13 illustrates an example in which the area S=300 and the SID is calculated to be 300 cm.

[0070] As an example, as shown in FIG. 14, the image analysis unit 70 extracts the center of gravity (here, the center of the rectangle) MC of a rectangle surrounded by lines connecting the centers of the markers M1 to M4 in an analysis image 80_3 of a captured image 75_3 captured in response to a third capture instruction. The image analysis unit 70 calculates the distance Δ in the Y-axis direction between the extracted center of gravity MC and a line LC that passes through the center of the captured image 75 and is parallel to the Z-axis. As described above, the line LC coincides with a line that passes through the irradiation center of the radiation R and is parallel to the Z-axis. Therefore, Δ represents the deviation from the irradiation center of the electronic cassette 10 in the Y-axis direction (hereinafter abbreviated as deviation from the irradiation center). In other words, Δ is nothing but the position relative to the irradiation center. The image analysis unit 70 outputs the calculated deviation Δ from the irradiation center to the display control unit 72 as an analysis result 76_3B. FIG. 14 illustrates an example in which the deviation Δ from the irradiation center is calculated to be +20 cm. For convenience, the process shown in FIG. 13 for calculating the SID and the process shown in FIG. 14 for calculating the deviation Δ from the irradiation center have been described separately, but the image analysis unit 70 performs the processes shown in FIGS. 13 and 14 in parallel.

[0071] 15, a third notification screen 125 that is displayed on the touch panel display 55 after the third imaging instruction has an illustration display area 126 and result display areas 127A and 127B. In the illustration display area 126, illustrations of the electronic cassette 10, the radiation source 11, and the subject H, as well as the SID, are displayed. The words "right" and "left" are displayed near the illustration of the electronic cassette 10.

[0072] The result display area 127A displays the analysis result 76_3A, more specifically, the SID. The result display area 127A also displays the amount of movement of the electronic cassette 10 and the radiation source 11 in the X-axis direction, which is derived from the analysis result 76_3A and is required to set the SID to a value associated with the imaging menu. If the SID is a value associated with the imaging menu, the amount of movement of the electronic cassette 10 and the radiation source 11 in the X-axis direction is not displayed, and instead a message is displayed indicating that it is not necessary to move the electronic cassette 10 and the radiation source 11 in the X-axis direction.

[0073] The result display area 127B displays the analysis result 76_3B, more specifically, the deviation Δ from the irradiation center. The result display area 127B also displays the direction and amount of movement of the first holder 14 for reducing the deviation Δ from the irradiation center, which are derived from the analysis result 76_3B. Here, the amount of movement of the first holder 14 for reducing the deviation Δ from the irradiation center is, for example, the amount of movement for eliminating the deviation Δ. The amount of movement for eliminating the deviation Δ may not only completely eliminate the deviation Δ, but also include an error that is generally acceptable in the technical field to which the technology of the present disclosure belongs and does not contradict the spirit of the technology of the present disclosure (e.g., an error of approximately 1% to 10%). Alternatively, the amount of movement of the first holder 14 for reducing the deviation Δ from the irradiation center may be the amount of movement for reducing the deviation Δ to less than a preset threshold. Note that if there is no deviation Δ from the irradiation center, the direction and amount of movement of the first holder 14 are not displayed, and instead, a message is displayed indicating that movement of the first holder 14 is unnecessary.

[0074] An OK button 128 is provided at the bottom of the third notification screen 125. The operator OP moves the electronic cassette 10 and the radiation source 11 along the X-axis and moves the first holder 14 along the Y-axis in accordance with the displays in the result display areas 127A and 127B, and then selects the OK button 128. When the OK button 128 is selected, the display switches to a screen for inputting an instruction to start irradiation of radiation R to the radiation source control device 12. Note that when the OK button 128 is selected, if the SID has not yet become the value associated with the imaging menu and / or if the deviation Δ from the irradiation center has not been sufficiently reduced, the display does not transition to the screen for inputting an instruction to start irradiation of radiation R to the radiation source control device 12, and the operator OP is prompted to adjust the positions of the electronic cassette 10 and the radiation source 11 again. Here, when the SID is not the value associated with the shooting menu, it means that the SID does not match the value associated with the shooting menu, or does not fall within a preset tolerance range (-5 cm < value associated with the shooting menu < +5 cm, etc.) centered on the value associated with the shooting menu. When the deviation Δ from the irradiation center has not been sufficiently reduced, it means that the deviation Δ from the irradiation center is not 0 cm, or does not fall within a preset tolerance range (-1 cm < Δ < +1 cm, etc.) centered on 0 cm.

[0075] Next, the operation of the above configuration will be described with reference to the flowcharts shown in FIGS. 16 and 17 as an example. First, as shown in FIG. 16, the operator OP carries the radiation imaging system 2 (electronic cassette 10, radiation source 11, radiation source control device 12, console 13, first holder 14, and second holder 16) into the imaging site (step ST100). The operator OP attaches the electronic cassette 10 to the first holder 14 and the radiation source 11 to the second holder 16 (step ST110). Then, the operator OP installs (temporarily places) the electronic cassette 10 and the radiation source 11 on the installation surface 15 at the imaging site via the first holder 14 and the second holder 16 (step ST120). At this time, the operator OP positions the electronic cassette 10 so that the detection surface 17 is aligned as closely as possible with the Z axis. The operator OP also positions the detection surface 17 of the electronic cassette 10 and the radiation source 11 so that at least the markers M3 and M4 and the string 34 are within the field of view of the camera 20.

[0076] The operator OP operates the console 13 to select an imaging menu and set irradiation conditions for the radiation R (step ST130). Subsequently, the operator OP operates the console 13 to issue a first imaging instruction to the camera 20 (step ST140). In response to this first imaging instruction, the camera 20 captures a captured image 75_1.

[0077] 6, the captured image 75_1 is analyzed by the image analysis unit 70, and the tilt α of the electronic cassette 10 around the X axis is detected (step ST150). The analysis result 76_1 including the tilt α of the electronic cassette 10 around the X axis is output from the image analysis unit 70 to the displacement amount calculation unit 71 and the display control unit 72.

[0078] 7, the displacement amount calculation unit 71 refers to the displacement amount calculation table 85 to calculate the displacement amount of the movable part 39 for reducing the deviation of the inclination of the electronic cassette 10 around the X axis (step ST160). The displacement amount calculation result 77_1 is output from the displacement amount calculation unit 71 to the display control unit 72.

[0079] 8, under the control of the display control unit 72, a first notification screen 90 is displayed on the touch panel display 55 of the console 13 (step ST170). The first notification screen 90 has a result display area 92 that displays the tilt α of the electronic cassette 10 around the X axis and the displacement amount of the movable unit 39 for reducing the deviation in the tilt of the electronic cassette 10 around the X axis. The operator OP adjusts the length of the movable unit 39 in accordance with the display in the result display area 92 (step ST180). Note that if the tilt α of the electronic cassette 10 around the X axis is 0°, step ST180 is omitted.

[0080] The operator OP selects the OK button 94 on the first notification screen 90 to issue a second imaging instruction to the camera 20 (step ST190). In response to this second imaging instruction, the camera 20 captures a photographed image 75_2.

[0081] 9 and 10, the captured image 75_2 is analyzed by the image analysis unit 70, thereby detecting the tilts β and γ of the electronic cassette 10 around the Y-axis and the Z-axis (step ST200). An analysis result 76_2A including the tilt β of the electronic cassette 10 around the Y-axis is output from the image analysis unit 70 to the displacement amount calculation unit 71 and the display control unit 72. Furthermore, an analysis result 76_2B including the tilt γ of the electronic cassette 10 around the Z-axis is output from the image analysis unit 70 to the display control unit 72.

[0082] 11, the displacement amount calculation unit 71 refers to the displacement amount calculation table 110 to calculate the displacement amount of the movable part 39 for reducing the deviation of the inclination of the electronic cassette 10 around the Y axis (step ST210). This displacement amount calculation result 77_2A is output from the displacement amount calculation unit 71 to the display control unit 72.

[0083] 12, under the control of the display control unit 72, a second notification screen 115 is displayed on the touch panel display 55 of the console 13 (step ST220). The second notification screen 115 has a result display area 116A that displays the tilt β of the electronic cassette 10 around the Y axis and the displacement amount of the movable unit 39 for reducing the tilt deviation of the electronic cassette 10 around the Y axis. The second notification screen 115 also has a result display area 116B that displays the tilt γ of the electronic cassette 10 around the Z axis and the rotation direction and rotation amount of the first holder 14 for reducing the tilt deviation of the electronic cassette 10 around the Z axis. The operator OP adjusts the length of the movable unit 39, etc., in accordance with the display in the result display areas 116A and 116B (step ST230). If the tilt β of the electronic cassette 10 around the Y axis is 0° and the tilt γ of the electronic cassette 10 around the Z axis is 0°, step ST230 is omitted.

[0084] 17, the operator OP selects the OK button 117 on the second notification screen 115 to issue a third imaging instruction to the camera 20 (step ST240). In response to this third imaging instruction, the camera 20 captures a photographed image 75_3.

[0085] As shown in Fig. 13, the captured image 75_3 is analyzed by the image analysis unit 70, and the area S of a rectangle surrounded by lines connecting the centers of the markers M1 to M4 is calculated. Then, by referring to the SID calculation table 120, the SID is calculated from the area S (step ST250). Furthermore, as shown in Fig. 14, the deviation Δ from the irradiation center is calculated (step ST250). An analysis result 76_3A including the SID and an analysis result 76_3B including the deviation Δ from the irradiation center are output from the image analysis unit 70 to the display control unit 72.

[0086] As shown in FIG. 15 , under the control of the display control unit 72, a third notification screen 125 is displayed on the touch panel display 55 of the console 13 (step ST260). The third notification screen 125 has a result display area 127A that displays the SID and the amount of movement of the electronic cassette 10 and the radiation source 11 in the X-axis direction to set the SID to a value associated with the imaging menu. The third notification screen 125 also has a result display area 127B that displays the deviation Δ from the irradiation center and the direction and amount of movement of the first holder 14 to reduce the deviation Δ from the irradiation center. The operator OP adjusts the positions of the electronic cassette 10 and the radiation source 11 (the positions of the first holder 14 and the second holder 16) according to the display in the result display areas 127A and 127B (step ST270). Note that if the SID is a value associated with the imaging menu and there is no deviation Δ from the irradiation center, step ST270 is omitted.

[0087] The operator OP selects the OK button 128 on the third notification screen 125. Next, the operator OP has the subject H stand in front of the electronic cassette 10 and adjusts the position and posture of the subject H by, for example, aligning the subject H's craniocaudal axis with the Z axis or by folding the subject's arms to the side (step ST280). The operator OP then operates the handle 36 of the first holder 14 to adjust the height of the electronic cassette 10 to suit the body shape of the subject H. Next, the operator OP operates the handle of the second holder 16 to adjust the height of the radiation source 11 to the height of the electronic cassette 10 (step ST290). Thereafter, the operator OP operates the console 13 to input an instruction to start irradiation of radiation R to the radiation source control device 12. As a result, radiation R is irradiated from the radiation source 11 toward the subject H, and the radiation R that has passed through the subject H is detected by the electronic cassette 10, and a radiological image is output from the electronic cassette 10 (step ST300). The radiation image is transmitted from the electronic cassette 10 to the console 13. Then, under the control of the display control unit 72, it is displayed on the touch panel display 55 and made available for viewing by the operator OP.

[0088] As described above, the radiography system 2 includes the radiation source 11 that emits radiation R, the electronic cassette 10 that receives radiation R and detects a radiographic image, the portable first holder 14 that holds the electronic cassette 10, the string 34 attached to the first holder 14, and the camera 20 that photographs the string 34. The first holder 14 includes a locking unit 38 and a movable unit 39 that serve as a tilt change mechanism that can change the tilt of the electronic cassette 10 with respect to the radiation source 11. The string 34 and the camera 20 constitute a first detection mechanism that detects the tilt α of the electronic cassette 10 around the X-axis, which is an axis that intersects the Z-axis and is the axis toward the radiation source 11 when the radiation R detection surface 17 of the electronic cassette 10 and the radiation source 11 are positioned opposite each other. The string 34 and the camera 20 can detect the tilt α of the electronic cassette 10 around the X axis, so that when the electronic cassette 10 is tilted around the X axis and radiography is performed on the subject H whose cranial axis is parallel to the Z axis, a radiographic image of the subject H at an angle is detected, reducing the risk of radiography failure.

[0089] The display control unit 72 controls the display of the tilt α of the electronic cassette 10 around the X axis on the touch panel display 55. This allows the operator OP to be notified of the tilt α of the electronic cassette 10 around the X axis, and can prompt the operator OP to take measures to reduce the deviation in the tilt of the electronic cassette 10 around the X axis.

[0090] The displacement amount calculation unit 71 calculates the displacement amount of the movable unit 39 for reducing the deviation in the tilt of the electronic cassette 10 around the X axis, based on the tilt α of the electronic cassette 10 around the X axis. The display control unit 72 controls the display of the calculated displacement amount of the movable unit 39 for reducing the deviation in the tilt of the electronic cassette 10 around the X axis on the touch panel display 55. This makes it possible to notify the operator OP of the displacement amount of the movable unit 39 for reducing the deviation in the tilt of the electronic cassette 10 around the X axis. The operator OP simply adjusts the length of the movable unit 39 in accordance with the displayed displacement amount, thereby easily reducing the deviation in the tilt of the electronic cassette 10 around the X axis.

[0091] The first detection mechanism includes a string 34 hanging down in a direction parallel to the Z axis and a camera 20 that captures an image of the string 34. The image analysis unit 70 detects the tilt α of the electronic cassette 10 around the X axis by analyzing an image 75_1 captured by the camera 20, the image 75_1 including the string 34. The string 34 can be anything that hangs down tightly in a direction parallel to the Z axis, and the camera 20 only needs to have a resolution sufficient to extract an image of the string 34 through image recognition. Therefore, the tilt α of the electronic cassette 10 around the X axis can be detected with a relatively inexpensive and simple configuration.

[0092] The camera 20 is provided on the radiation source 11. Therefore, it is possible to easily associate the angle of view of the camera 20 with the irradiation field of the radiation R, for example, by aligning a line LC that passes through the center of the captured image 75 and is parallel to the Z axis with a line that passes through the irradiation center of the radiation R and is parallel to the Z axis. Note that in the technology disclosed herein, the phrase "a camera is provided on the radiation source" is a concept that encompasses both a case in which the radiation source 11 and the camera 20 are separate entities and the camera 20 is "attached" to the radiation source 11, as in this embodiment, and a case in which the camera 20 is "integrally built" into the radiation source 11.

[0093] The electronic cassette 10 is provided with markers M1 to M4 and a camera 20 as a second detection mechanism for detecting tilts β and γ of the electronic cassette 10 around the Y axis and the Z axis. Since it is possible to detect not only tilt α of the electronic cassette 10 around the X axis but also tilts β and γ of the electronic cassette 10 around the Y axis and the Z axis, it is possible to reduce the risk of radiography failure caused by radiographic images being detected in which the irradiation of radiation R differs vertically or horizontally when radiographic images are detected in which the irradiation of radiation R differs vertically or horizontally.

[0094] The display control unit 72 controls the display of the tilts β and γ of the electronic cassette 10 around the Y axis and the Z axis on the touch panel display 55. This makes it possible to notify the operator OP of the tilts β and γ of the electronic cassette 10 around the Y axis and the Z axis, and to prompt the operator OP to take measures to reduce the deviation in the tilt of the electronic cassette 10 around the Y axis and the Z axis.

[0095] The displacement amount calculation unit 71 calculates the displacement amount of the movable unit 39 for reducing the deviation in the tilt of the electronic cassette 10 around the Y axis based on the tilt β of the electronic cassette 10 around the Y axis. The display control unit 72 controls the display of the calculated displacement amount of the movable unit 39 for reducing the deviation in the tilt of the electronic cassette 10 around the Y axis on the touch panel display 55. This makes it possible to notify the operator OP of the displacement amount of the movable unit 39 for reducing the deviation in the tilt of the electronic cassette 10 around the Y axis. The operator OP simply adjusts the length of the movable unit 39 in accordance with the displayed displacement amount, thereby easily reducing the deviation in the tilt of the electronic cassette 10 around the Y axis.

[0096] As an example of a tilt change mechanism that can change the tilt of the electronic cassette 10 around the Z axis, the first holder 14 may be provided with a rotation mechanism that rotates the electronic cassette 10 around the Z axis while maintaining the positional relationship between the legs 33A to 33C. In this case, the displacement amount calculation unit 71 calculates the amount of rotation of the rotation mechanism that reduces the tilt deviation of the electronic cassette 10 around the Z axis based on the tilt γ of the electronic cassette 10 around the Z axis, in addition to the amount of displacement of the movable unit 39 that reduces the tilt deviation of the electronic cassette 10 around the Y axis. The display control unit 72 also displays the amount of rotation of the rotation mechanism that reduces the tilt deviation of the electronic cassette 10 around the Z axis on the touch panel display 55, as in the result display area 116B of the second notification screen 115 shown in FIG. 18 , for example.

[0097] The second detection mechanism includes four markers M1 to M4 provided on the first holder 14 and a camera 20 that captures images of the markers M1 to M4. The image analysis unit 70 detects the tilts β and γ of the electronic cassette 10 around the Y axis and the Z axis by analyzing the captured image 75_2 by the camera 20. Therefore, the tilts β and γ of the electronic cassette 10 around the Y axis and the Z axis can be detected with a relatively inexpensive and simple configuration.

[0098] The image analysis unit 70 analyzes the captured image 75_3 of the camera 20 to further detect SID, which is the distance from the generation point of the radiation R to the detection surface 17 of the electronic cassette 10, and the deviation Δ from the irradiation center, which is the position of the electronic cassette 10 relative to the irradiation center of the radiation R on the YZ plane defined by the Y axis and the Z axis. Therefore, it is possible to set the SID as a value associated with the imaging menu and reduce the deviation Δ from the irradiation center, further reducing the risk of failure in radiation imaging.

[0099] The first holder 14 includes a holder 30 to which the electronic cassette 10 is attached, and three legs 33A to 33C that support the holder 30. As such, the first holder 14 has a very simple configuration, so it can be easily carried to the imaging location, and can also be easily installed on the installation surface 15 at the imaging location. Note that the first holder 14 is not limited to the exemplified tripod, but may be a four-legged or five-legged structure, etc. In other words, the number of legs 33 may be four or more.

[0100] The markers M1 to M4 are provided on the holder 30. This prevents the markers M1 to M4 from appearing in a radiographic image. Furthermore, by providing the markers M1 to M4 at positions on the holder 30 where they are not hidden by the subject H standing in front of the electronic cassette 10, it is possible to adjust the position and attitude of the electronic cassette 10 relative to the radiation source 11 after the subject H has stood in front of the electronic cassette 10. As with the above-described case where "a camera is provided on the radiation source," in the technology of the present disclosure, "markers are provided on the holder" conceptually encompasses both a case where the holder 30 and the markers M1 to M4 are separate entities and the markers M1 to M4 are "attached" to the holder 30, as in this embodiment, and a case where the markers M1 to M4 are "integrally built" into the holder 30.

[0101] 19, the markers M1 to M4 may be provided on the electronic cassette 10. In this case, however, it is preferable to provide the markers M1 to M4 away from the detection surface 17 of the radiation R in order to prevent the markers M1 to M4 from appearing in the radiation image.

[0102] The first holder 14 includes a fixing mechanism 45 that fixes the positional relationship between the holder 30 and the legs 33A to 33C. Therefore, the positional relationship between the holder 30 and the legs 33A to 33C can always be fixed in the state shown in FIG. 3. When the subject H stands in front of the electronic cassette 10, the legs 33A to 33C do not get in the way. Furthermore, the displacement amount calculation tables 85 and 110 can be created on the premise that the positional relationship between the holder 30 and the legs 33A to 33C is fixed, and the displacement amount of the movable part 39 can be easily calculated by referring to the displacement amount calculation tables 85 and 110.

[0103] [Second embodiment] In the first embodiment, the string 34 and the camera 20 are exemplified as the first detection mechanism, but the present invention is not limited to this. In the second embodiment, an acceleration sensor 130 is used as the first detection mechanism.

[0104] 20, an acceleration sensor 130 is built into the center of the holder 30 of the first holder 14 of the second embodiment. The acceleration sensor 130 is preset to output gravitational acceleration g as a measurement result 136 (see FIG. 21) when the tilt α of the electronic cassette 10 around the X axis is 0°.

[0105] 21, the CPU 58 of the console 13 of the second embodiment includes a tilt calculation unit 135 in addition to the units 70 to 72 of the first embodiment. The tilt calculation unit 135 receives a measurement result 136 from the acceleration sensor 130. When the measurement result 136 is AC, the tilt calculation unit 135 calculates the tilt α of the electronic cassette 10 around the X axis using the following equation (1). α=cos -1 (AC / g) (1) The tilt calculation unit 135 outputs the analysis result 76_1 including the calculated tilt α of the electronic cassette 10 around the X axis to the displacement amount calculation unit 71 and the display control unit 72.

[0106] As described above, in the second embodiment, the first detection mechanism includes the acceleration sensor 130. The tilt calculation unit 135 detects the tilt α of the electronic cassette 10 around the X axis based on the measurement result 136 of the acceleration sensor 130. The tilt α of the electronic cassette 10 around the X axis can be detected using only the acceleration sensor 130, which is an even cheaper and simpler configuration than the string 34 and camera 20. The acceleration sensor 130 may be built into the electronic cassette 10 instead of the holder 30.

[0107] The center pole 31 may be moved up and down using an actuator such as a motor. In this case, the up and down movement of the center pole 31 may be configured to be remotely controlled by a remote controller. Not only the center pole 31 of the first holder 14, but also the center pole of the second holder 16 may be moved up and down using an actuator such as a motor, and the up and down movement may be remotely controlled by a remote controller. Furthermore, the first holder 14 and the second holder 16 may be connected to each other so that they can communicate with each other, and the center pole of the second holder 16 may also be moved up and down in conjunction with the up and down movement of the center pole 31 of the first holder 14.

[0108] The extension and contraction of the movable part 39 may also be performed using an actuator such as a motor, and the movable part 39 may be automatically extended and contracted without the assistance of an operator OP in accordance with the amount of displacement calculated by the displacement amount calculation unit 71. In this case, there is no need to display on the touch panel display 55 the tilt of the electronic cassette 10 and the amount of displacement of the movable part 39 required to reduce the deviation in the tilt of the electronic cassette 10.

[0109] The inclinations β and γ of the electronic cassette 10 around the Y axis and the Z axis may be calculated first, and then the inclination α of the electronic cassette 10 around the X axis may be calculated later.

[0110] The fixing mechanism for fixing the positional relationship between the holder 30 and the legs 33 is not limited to the fixing mechanism 45 (click stop mechanism) exemplified in the first embodiment. It may be a fixing mechanism that fixes the holder 30 and the legs 33 so that they cannot rotate in the positional relationship shown in Fig. 3. Alternatively, the legs 33 may be configured to be freely rotatable relative to the main body 32, and a marker may be attached to the main body 32 at a location that will achieve the positional relationship shown in Fig. 3.

[0111] The second detection mechanism only needs to include at least three markers. Therefore, five or more markers may be used. When adjusting the position and attitude of the electronic cassette 10 relative to the radiation source 11 after the subject H stands in front of the electronic cassette 10, at least three markers that are not hidden by the subject H may be used to detect the tilt α of the electronic cassette 10 around the X axis.

[0112] The string 34 may be hung from the electronic cassette 10. Assuming that the string 34 may sway due to wind or the like, a mechanism for suppressing the swaying of the string 34 may be provided. In addition, the marker constituting the second detection mechanism may be printed on the electronic cassette 10 or the holder 30.

[0113] Although an electronic cassette is used as an example of the radiation image detector, the present invention is not limited to this and may be a film cassette or an IP (Imaging Plate) cassette.

[0114] In the above-described embodiments, various screens such as the first notification screen 90, the second notification screen 115, and the third notification screen 125 are displayed on the touch panel display 55 of the console 13, which is a display device, under the control of the display control unit 72 of the CPU 58 of the console 13. However, the present invention is not limited to this. Screen data for various screens such as the first notification screen 90, the second notification screen 115, and the third notification screen 125 may be generated by the console 13, and the generated screen data may be distributed from the console 13 to another external device having a display device, such as a smartphone owned by an operator OP. In this case, the touch panel display of the smartphone is an example of a "display device" according to the technology of the present disclosure.

[0115] In each of the above embodiments, the following various processors can be used as the hardware structure of the processing unit that executes various processes, such as the image analysis unit 70, the displacement amount calculation unit 71, the display control unit 72, and the tilt calculation unit 135. As described above, the various processors include the CPU 58, which is a general-purpose processor that executes software (operating program 60) and functions as various processing units, as well as dedicated electrical circuits that are processors having a circuit configuration specifically designed to execute specific processes, such as a programmable logic device (PLD) that is a processor whose circuit configuration can be changed after manufacture, such as an FPGA (Field Programmable Gate Array), and an ASIC (Application Specific Integrated Circuit).

[0116] A single processing unit may be configured with one of these various processors, or may be configured with a combination of two or more processors of the same or different types (e.g., a combination of multiple ASICs and / or a combination of an ASIC and an FPGA). Also, multiple processing units may be configured with a single processor.

[0117] Examples of configuring multiple processing units with a single processor include, first, a form in which one processor is configured with a combination of one or more CPUs and software, and this processor functions as multiple processing units, as typified by client and server computers. Second, a form in which a processor is used to realize the functions of an entire system including multiple processing units with a single IC (Integrated Circuit) chip, as typified by System on Chip (SoC). In this way, various processing units are configured using one or more of the above-mentioned various processors as a hardware structure.

[0118] Furthermore, more specifically, the hardware structure of these various processors can be an electric circuit that combines circuit elements such as semiconductor elements.

[0119] The technology of the present disclosure can be appropriately combined with the various embodiments and / or various modified examples described above. Furthermore, it is not limited to the above-described embodiments, and various configurations can be adopted without departing from the spirit of the present disclosure. Furthermore, the technology of the present disclosure extends not only to programs but also to storage media that non-temporarily store programs.

[0120] The above-described description and illustrations are a detailed explanation of the parts related to the technology of the present disclosure and are merely an example of the technology of the present disclosure. For example, the above description of the configuration, functions, actions, and effects is an explanation of an example of the configuration, functions, actions, and effects of the parts related to the technology of the present disclosure. Therefore, it goes without saying that unnecessary parts may be deleted, new elements may be added, or replacements may be made to the above-described description and illustrations within the scope of the gist of the technology of the present disclosure. Furthermore, to avoid confusion and facilitate understanding of the parts related to the technology of the present disclosure, the above-described description and illustrations omit explanations of common technical knowledge that do not require particular explanation to enable the implementation of the technology of the present disclosure.

[0121] In this specification, "A and / or B" is synonymous with "at least one of A and B." In other words, "A and / or B" means that it may be only A, only B, or a combination of A and B. Furthermore, in this specification, the same concept as "A and / or B" is also applied when three or more things are expressed connected by "and / or."

[0122] All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference. [Explanation of symbols]

[0123] 2 Radiography system 10 Electronic Cassette 11 Radiation source 12 Radiation source control device 13 Console 14 1st retainer 15 Installation surface 16 Second cage 17 Detection surface 18 Radiation tube 19 Irradiation field limiter 20 Camera 30 Holder 31 Center Pole 32 Main body 33, 33A, 33B, 33C legs 34 String 35 weight 36 Handle 37 Base 38 Rock Club 39 Moving parts 40 stone tip 45 Fixing mechanism 46 Holding part 47 Click Ball 48 Rotating part 49 Groove 55 Touch Panel Display 56 Storage 57 Memory 58 CPU 59 Communication I / F 60 Operating Program 70 Image analysis unit 71 Displacement calculation unit 72 Display control unit 75 images 76 Analysis results 77 Displacement calculation results 80 Analysis Images 85, 110 Displacement calculation table 90 First notification screen 91, 126 Illustration display area 92, 116A, 116B, 127A, 127B Result display area 93 Guide display area 94, 117, 128 OK button 100 Formula for calculating the tilt of the electronic cassette around the Y axis 105 Formula for calculating the tilt of the electronic cassette around the Z axis 115 Second notification screen 120 SID calculation table 125 Third Notification Screen 130 Acceleration Sensor 135 Tilt calculation unit 136 Measurement results α Tilt of electronic cassette around X axis β Tilt of electronic cassette around Y axis γ Tilt of electronic cassette around Z axis Δ Deviation from the irradiation center of the electronic cassette in the Y-axis direction H Subject L Line connecting the centers of the markers LC: A line parallel to the Z axis that passes through the center of the captured image LS: Lines following the string M1, M2, M3, M4 markers MC Center of gravity of the rectangle bounded by lines connecting the centers of the markers OP Operator R Radiation S Area of ​​the rectangle enclosed by the line connecting the centers of the markers SID Distance from the radiation source to the detection surface of the electronic cassette ST100, ST110, ST120, ST130, ST140, ST150, ST160, ST170, ST180, ST190, ST200, ST210, ST220, ST230, ST240, ST250, ST260, ST270, ST280, ST290, ST300 Step

Claims

1. a radiation source that emits radiation; a radiation image detector that receives the radiation and detects a radiation image; a portable holder including a holder to which the radiographic image detector is attached and at least three legs that support the holder, the holder including an inclination change mechanism that can change the inclination of the radiographic image detector with respect to the radiation source; a first detection mechanism for detecting a tilt of the radiographic image detector around a first axis that intersects a vertical axis and points toward the radiation source when the radiation detection surface of the radiographic image detector and the radiation source are disposed opposite each other; A radiography system comprising:

2. a first processor; The first processor The radiation imaging system according to claim 1 , wherein the tilt of the radiation image detector around the first axis is displayed on a display.

3. The first processor calculating a displacement amount of the tilt changing mechanism for reducing a deviation in the tilt of the radiographic image detector about the first axis based on the tilt of the radiographic image detector about the first axis; The radiation imaging system according to claim 2 , wherein the calculated amount of displacement is displayed on the display.

4. the first detection mechanism includes a string hanging down in a direction parallel to the vertical axis and a first camera that captures an image of the string; The first processor The radiation imaging system according to claim 2 or 3, wherein the tilt of the radiation image detector around the first axis is detected by analyzing an image captured by the first camera including the string.

5. The radiation imaging system according to claim 4 , wherein the first camera is provided on the radiation source.

6. the first detection mechanism includes an acceleration sensor; The first processor 4. The radiation imaging system according to claim 2, wherein the tilt of the radiation image detector around the first axis is detected based on the measurement result of the acceleration sensor.

7. 7. The radiation imaging system according to claim 1, further comprising a second detection mechanism for detecting a tilt of the radiation image detector around at least one of the vertical axis and a second axis intersecting the vertical axis and the first axis.

8. a second processor; The second processor The radiation imaging system according to claim 7 , wherein the tilt of the radiation image detector around at least one of the vertical axis and the second axis is displayed on a display.

9. The second processor calculating a displacement amount of the tilt changing mechanism for reducing a deviation in the tilt of the radiographic image detector around at least one of the vertical axis and the second axis based on the tilt of the radiographic image detector around at least one of the vertical axis and the second axis; The radiation imaging system according to claim 8 , wherein the calculated displacement amount is displayed on the display.

10. the second detection mechanism includes at least three markers provided on the radiation image detector or the holder, and a second camera that captures images of the markers; The second processor The radiation imaging system according to claim 8 or 9, wherein the tilt of the radiation image detector around at least one of the vertical axis and the second axis is detected by analyzing the image captured by the second camera.

11. The second processor 11. The radiation imaging system according to claim 10, further comprising: an image capturing unit configured to analyze the image captured by the second camera, and further configured to detect a distance from the point of generation of the radiation to the detection surface of the radiation image detector, and a position of the radiation image detector relative to an irradiation center of the radiation on a plane defined by the vertical axis and the second axis.

12. 12. The radiation imaging system according to claim 10, wherein the second camera is provided on the radiation source.

13. 13. The radiation imaging system according to claim 10, wherein the marker is provided on the holder.

14. The radiography system according to claim 1 , wherein the holder includes a fixing mechanism that fixes the positional relationship between the holder and the leg portion.

Images