Radiography system and control method thereof

Abstract

To provide a radiographic system capable of reducing cases of contacts between a subject and an engineer and safely positioning the subject, and a control method of the radiographic system.SOLUTION: The radiographic system comprises: a radiation source which emits radiation; a photography platform which has a detection panel for detecting the radiation and generating a radiation image; a vertical movement device on which a subject is placed; a deviation amount detection device which detects a relative deviation amount between the photography platform and the subject; and a vertical movement control device which vertically moves the vertical movement device based on the deviation amount detected by the deviation amount detection device.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology disclosed herein relates to a radiation imaging system and a control method thereof. [Background technology]

[0002] Due to the recent spread of the novel coronavirus, mass infections known as clusters have also occurred in medical institutions. For this reason, when performing radiography on subjects such as patients at medical institutions, it is preferable to appropriately align the subject on the imaging table while reducing the chance of contact between the subject and the technician from the perspective of preventing infection. However, currently, technicians enter the radiation room to directly align the subject, which results in many opportunities for contact between the subject and the technician.

[0003] As a technology that enables a technician to align a subject without contacting the subject, a radiography system equipped with a lifting device that raises and lowers a lifting table on which the subject rests relative to the imaging table is known (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-177211 A [Patent Document 2] JP 2005-031323 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the radiography systems described in Patent Documents 1 and 2, the position of the subject is adjusted by manually operating the lifting device while the technician is checking the position, which may cause problems with the subject's safety if the technician is not very skilled. Also, if the lifting device is automatically controlled to raise and lower the device without the technician's checking, problems with the subject's safety, such as unintended inching, may occur.

[0006] The technology disclosed herein aims to provide a radiography system and a control method thereof that reduce the opportunities for contact between a subject and a technician and enable safe positioning of the subject. [Means for solving the problem]

[0007] The portable radiation detector of the present disclosure includes a radiation source that emits radiation, an imaging table having a detection panel that detects radiation and generates a radiological image, a lifting device on which a subject is placed, a positional deviation detection device that detects the amount of relative positional deviation between the imaging table and the subject, and a lifting control device that raises and lowers the lifting device based on the amount of positional deviation detected by the positional deviation detection device.

[0008] The lift control device preferably controls the lift device in a direction to lower the lift device from the initial position and in a direction to reduce the amount of positional deviation.

[0009] The lift control device preferably controls the lift speed of the lift device in accordance with the amount of positional deviation.

[0010] It is preferable that the lift control device increases the lift speed when the amount of positional deviation is large, and decreases the lift speed when the amount of positional deviation is small.

[0011] The lift control device preferably detects the subject's body movement based on the change in the positional deviation amount and the lift speed.

[0012] It is preferable that the lift control device detects the difference between the change in the positional deviation amount and the lift speed as the subject's body movement speed, and sets the lift speed to a certain value or below when the detected body movement speed is above a certain value.

[0013] The positional deviation detection device preferably includes a camera provided in the radiation source for photographing the subject, and an image analysis device for detecting the amount of positional deviation by analyzing the image acquired by the camera.

[0014] It is preferable that the image analysis device detects a characteristic part of the subject from the image, and detects the amount of positional deviation based on the difference between the position of the detected characteristic part and the target area on the imaging table.

[0015] The characteristic site is preferably an anatomical feature of the subject or a marker on the examination gown.

[0016] It is preferable that the characteristic portions and the target areas are set in advance for each imaging menu, and the image analysis device selects the characteristic portions and the target areas for detecting the amount of positional deviation in accordance with the imaging menu.

[0017] The lift control device preferably stops lifting or lowering of the lift device when it is predicted, based on the image, that the subject will collide with an object.

[0018] It is preferable that the lift control device issues a warning when it is predicted that the subject will collide with an object based on the image.

[0019] The control method for a radiography system disclosed herein is a control method for a radiography system including a radiation source that emits radiation, an imaging table having a detection panel that detects the radiation and generates a radiographic image, a lifting device on which a subject is placed, and a positional deviation detection device that detects the amount of relative positional deviation between the imaging table and the subject, and raises and lowers the lifting device based on the amount of positional deviation detected by the positional deviation detection device. Effect of the Invention

[0020] According to the technique of the present disclosure, it is possible to provide a radiography system and a control method thereof that reduce the opportunities for contact between a subject and a technician and enable safe positioning of the subject. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of the configuration of a radiation imaging system. [Diagram 2] FIG. 2 is a block diagram showing an example of a configuration of a control device. [Diagram 3] 10A and 10B are schematic diagrams illustrating an example of a process for detecting a positional deviation amount by an image analyzing device. [Figure 4] FIG. 13 is a schematic diagram showing an example of a state in which a characteristic portion exists within a target area. [Diagram 5] 4 is a schematic diagram showing an example of lift control of the lift device by the lift control device; FIG. [Figure 6] 11 is a graph showing an example of a relationship between a lifting speed and a positional deviation amount in lifting control. [Figure 7] 10 is a flowchart showing an example of a positioning operation of a subject performed by a radiation imaging system. [Figure 8] FIG. 13 is a schematic diagram showing the configuration of a radiation imaging system according to a first modified example. [Figure 9] FIG. 11 is a schematic diagram showing lift control according to a second modified example. [Figure 10] 13 is a flowchart showing a procedure for alignment and imaging in the second modified example. [Figure 11] FIG. 2 is a schematic diagram showing an example of a light field appearing in an image. [Figure 12] 13 is a flowchart showing lift control according to a third modification. [Figure 13] 13 is a flowchart showing lift control according to a fourth modified example. [Figure 14] FIG. 13 is a diagram showing an example of a setting table in which characteristic portions and target areas are set for each imaging menu. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] 1 as an example, a radiation imaging system 10 includes a radiation generator 11, an imaging stand 12, a lifting device 13, a camera 14, a control device 15, an operation unit 16, and an information output unit 17. The radiation generator 11, the imaging stand 12, the lifting device 13, and the camera 14 are provided in a radiation room 20 where radiation imaging is performed on a subject H. The control device 15, the operation unit 16, and the information output unit 17 are provided in an operation room 21 adjacent to the radiation room 20. It should be noted that the control device 15 may be provided in the radiation room 20.

[0023] A window (not shown) is provided between the radiation room 20 and the operation room 21. In the operation room 21, the technician 24 operates the operation unit 16 while checking the inside of the radiation room 20 through the window, thereby issuing an instruction to start positioning the subject H with respect to the imaging stand 12 and an instruction to start imaging the subject H.

[0024] The radiation generating device 11 includes a radiation source 30. The radiation source 30 is composed of a radiation tube 31 and a collimator 32. The radiation tube 31 generates radiation R by applying a high voltage current. The radiation R is, for example, an X-ray. A collimator 32 is attached to the exit side of the radiation tube 31. The collimator 32 is an irradiation field limiting device configured to narrow down the irradiation range of the radiation R emitted from the radiation tube 31. The collimator 32 is configured by combining a plurality of flat plates made of, for example, lead.

[0025] In this embodiment, the radiation source 30 is held by a stand 33 installed on the floor surface 22 of the radiation room 20. The stand 33 is connected to the radiation source 30 via a connection part 34. The stand 33 holds the radiation source 30 so as to be movable in the vertical direction (Z direction). The stand 33 is attached to a floor-traveling device (not shown). That is, the radiation generating device 11 of this embodiment is a floor-traveling type.

[0026] The radiation source 30 is connected to the control device 15 by wire or wirelessly. The control device 15 causes the radiation source 30 to generate radiation R in response to the operation of the operation unit 16 by the technician 24.

[0027] In this embodiment, the imaging table 12 is a standing imaging table for imaging the subject H in a standing position. The imaging table 12 has a stand 40, a connection part 41, and a holder 42. The stand 40 is installed on the floor surface 22 of the radiation room 20. The stand 40 is connected to the holder 42 via the connection part 41. The stand 40 holds the holder 42 so that it can move in the vertical direction.

[0028] Holder 42 is box-shaped and houses detection panel 43 therein. Most of holder 42 is made of a conductive material having electromagnetic wave shielding properties, such as aluminum or stainless steel. Moreover, most of the surface of holder 42 that faces radiation source 30 is made of a material that transmits radiation R, such as carbon. Holder 42 has a size that complies with the international standard ISO (International Organization for Standardization) 4090:2001, similar to, for example, a film cassette, an IP (Imaging Plate) cassette, or a CR (Computed Radiography) cassette.

[0029] The detection panel 43 is a so-called radiation FPD (Flat Panel Detector). As an example, the detection panel 43 is an indirect conversion type radiation FPD that converts radiation into visible light using a scintillator and converts the visible light into electric charges using a photodiode. Note that the detection panel 43 may be a direct conversion type radiation FPD that directly converts radiation into electric charges using a conversion layer such as amorphous selenium (a-Se).

[0030] The detection panel 43 has a built-in battery and is portable. The detection panel 43 also includes an amount detection sensor that detects the amount of radiation R irradiated, and automatically detects the start of irradiation of radiation R from the radiation source 30 and starts a radiographic operation. The detection panel 43 generates a radiographic image by detecting the radiation R that is emitted from the radiation source 30 and has passed through the imaging site of the subject H.

[0031] The detection panel 43 is connected to the control device 15 by wire or wirelessly. The detection panel 43 transmits the generated radiation image to the control device 15 after the radiation imaging is completed.

[0032] The radiation generating device 11 and the imaging stand 12 are disposed such that the radiation source 30 and the detection panel 43 are spaced a certain distance apart in the horizontal direction (V direction). The positions of the radiation generating device 11 and the imaging stand 12 are set such that the irradiation range of the radiation R is included in the detection surface of the detection panel 43.

[0033] The lifting device 13 is installed on the floor surface 22 of the radiation room 20. Specifically, the lifting device 13 is installed at a position between the radiation generating device 11 and the imaging table 12 and close to the imaging table 12. The lifting device 13 moves up and down with the subject H placed thereon, thereby enabling alignment of the subject H in the vertical direction. A marker M indicating an appropriate standing position for the subject H is formed on a top plate 13A of the lifting device 13.

[0034] The lifting device 13 is connected to the control device 15 by wire or wirelessly. The control device 15 detects the amount of relative positional deviation between the imaging platform 12 and the subject H based on the image acquired by the camera 14, and raises and lowers the lifting device 13 based on the detected amount of positional deviation.

[0035] The camera 14 is an imaging device that optically captures an image of the subject H placed on the lifting device 13. The camera 14 is, for example, a digital camera with a built-in CMOS (Complementary Metal Oxide Semiconductor) image sensor, and captures a visible light image. Note that the camera 14 is not limited to visible light, and may be an infrared camera that captures an infrared image.

[0036] The camera 14 is attached to, for example, the radiation source 30 so that the field of view includes a holder 42 that holds a detection panel 43. Specifically, the camera 14 is attached to a collimator 32. The camera 14 is connected to the control device 15 by wire or wirelessly.

[0037] The control device 15 is, for example, a console installed in an operation room 21. The console is a computer including a processor such as a CPU (Central Processing Unit), a memory, and a storage device. The storage device stores programs for operating the processor. The operation unit 16 is an input device such as a keyboard, a mouse, and a switch. The information output unit 17 is an output device such as a display, a speaker, etc.

[0038] The operation unit 16 is configured to be able to accept input operations by the technician 24. By operating the operation unit 16, the technician 24 can give an instruction to start positioning the subject H by the lifting device 13 and an instruction to emit radiation R from the radiation source 30 (i.e., an instruction to start radiography).

[0039] As an example, as shown in Fig. 2, the control device 15 is configured with an imaging control device 50, an image analysis device 51, and an elevation control device 52. The functions of each device are realized by a processor executing processing based on a program. The imaging control device 50, the image analysis device 51, and the elevation control device 52 may each be configured as separate devices. Furthermore, when the control device 15 is configured with multiple devices, some of the multiple devices may be installed in the radiation room 20, and the other devices may be installed in the operation room 21.

[0040] An imaging menu is input to the imaging control device 50 by the technician 24 or the like. The imaging control device 50 controls radiography by the radiation source 30 and the detection panel 43 based on the irradiation conditions according to the input imaging menu. The imaging control device 50 also receives radiographic images transmitted from the detection panel 43, and causes the information output unit 17 to display the received radiographic images.

[0041] The imaging control device 50 is communicably connected to a Radiology Information System (RIS) via a network such as a Local Area Network (LAN). The imaging control device 50 receives an imaging order from the RIS. The imaging order includes patient information of the subject H and an imaging menu. The imaging control device 50 is also communicably connected to an image database server (not shown) via the network. The image database server is, for example, a Picture Archiving and Communication System (PACS) server, which receives radiation images from the imaging control device 50 and stores and manages the received radiation images.

[0042] The image analysis device 51 detects the amount of relative positional deviation D between the imaging table 12 and the subject H by analyzing the image P acquired by the camera 14, and outputs the detected amount of positional deviation D to the lift control device 52.

[0043] The lift control device 52 controls the lifting of the lift device 13 based on the positional deviation amount D input from the image analysis device 51 so that the positional deviation amount D approaches zero.

[0044] 3 shows an example of detection processing of the positional deviation amount D by the image analysis device 51. The image analysis device 51 acquires an image P from the camera 14, and detects a characteristic part F representing an anatomical feature of the subject H captured in the image P. In this embodiment, an image of the chest of the subject H is taken in a standing position PA direction. In this embodiment, the characteristic part F is a "vertebral prominence." The image analysis device 51 detects the characteristic part F by a method such as pattern matching or machine learning.

[0045] Furthermore, after detecting the characteristic portion F from the image P, the image analysis device 51 detects the amount of positional deviation D based on the difference between the position of the characteristic portion F and the target area T on the imaging stand 12. In this embodiment, the target area T is set within the area corresponding to the detection panel 43 and above the center of the image P (+Z direction side). For example, the target area T is a rectangular area extending in the X direction. The width of the target area T in the Z direction is, for example, 40 mm.

[0046] The image analysis device 51 measures the difference in the Z direction between the characteristic portion F and the target area T in the image P. The difference obtained by the measurement is the amount of misalignment D. In this manner, the camera 14 and the image analysis device 51 constitute a "misalignment amount detection device" according to the technology of the present disclosure.

[0047] 4 shows an example of a state in which characteristic site F is present within target region T, i.e., a state in which positional deviation D is 0. Lifting control device 52 controls the lifting of lifting device 13 so that positional deviation D approaches 0 and eventually reaches 0. In this embodiment, the state in which positional deviation D is 0 means that the chest of subject H faces detection panel 43 directly, which is suitable for chest imaging.

[0048] 5 shows an example of lift control of the lift device 13 by the lift control device 52. In this embodiment, the lift control device 52 sets the lowest position of the top plate 13A of the lift device 13 as the initial position so that the subject H can easily get on the top plate 13A of the lift device 13. After the subject H gets on the lift device 13, the lift control device 52 controls the lift device 13 in a direction to raise the lift device 13 from the initial position and in a direction to reduce the positional deviation amount D.

[0049] FIG. 6 shows an example of the relationship between the lifting speed V and the positional deviation amount D in the lifting control. The lifting control device 52 controls the lifting speed V of the lifting device according to the positional deviation amount D to prevent the lifting device 13 from suddenly stopping and to improve the safety of the subject H. Specifically, as shown in FIG. 6 as an example, the lifting control device 52 sets the lifting speed V to a high speed when the positional deviation amount D is large and sets the lifting speed V to a low speed when the positional deviation amount D is small. In FIG. 6, the relationship between the lifting speed V and the positional deviation amount D is linear, but the relationship between the lifting speed V and the positional deviation amount D may be nonlinear. The lifting control device 52 may also control the lifting of the lifting device 13 by PID (Proportional-Integral-Differential) control.

[0050] 7 is a flow chart showing an example of the positioning operation of the subject H by the radiation imaging system 10 having the above-mentioned configuration. First, the technician 24 in the operation room 21 instructs the subject H in the radiation room 20 to stand on the top board 13A of the lifting device 13. After confirming that the subject H is standing in the correct position according to the marker M on the top board 13A, the technician 24 operates the operation unit 16 to start positioning the subject H with respect to the imaging table 12.

[0051] The control device 15 determines whether or not an alignment start instruction has been received from the operation unit 16 (step S10). When the control device 15 determines that an alignment start instruction has been received (step S10: YES), the image analysis device 51 acquires the image P captured by the camera 14 (step S11).

[0052] The image analysis device 51 detects a characteristic portion F from the acquired image P (step S12). The image analysis device 51 derives a positional deviation amount D based on the position of the detected characteristic portion F and the position of the target region T (step S13).

[0053] The lifting device 13 determines whether the positional deviation amount D derived by the image analysis device 51 is 0 or not (step S14), and if the positional deviation amount D is not 0 (step S14: NO), controls the lifting device 13 to raise and lower so that the positional deviation amount D approaches 0 (step S15). After that, the process returns to step S11, and the image analysis device 51 acquires the image P captured by the camera 14.

[0054] Steps S11 to S15 are repeated until it is determined in step S14 that the positional deviation amount D is 0. If it is determined in step S14 that the positional deviation amount D is 0 (step S14: YES), the position alignment operation ends.

[0055] After completing the positioning of the subject H, the technician 24 operates the operation unit 16 to cause the imaging control device 50 to perform radiation imaging.

[0056] As described above, according to the radiation imaging system 10 of the present disclosure, the technician 24 can perform accurate alignment without contacting the subject H. Therefore, it is possible to reduce the chance of contact between the subject H and the technician 24 and to perform the alignment of the subject safely.

[0057] After the positioning of the subject H is completed, the technician 24 may use the operation unit 16 to control the elevation of the elevator 13, thereby allowing fine adjustment of the height of the subject H.

[0058] Various modifications of the above embodiment will be described below.

[0059] [First Modification] In the above embodiment, the radiation generating device 11 is a floor-traveling type, but it may be a ceiling-traveling type. Fig. 8 shows the configuration of a radiation imaging system 10A according to a first modified example. The radiation imaging system 10A includes a ceiling-traveling radiation generating device 11A. The radiation generating device 11A has an arm 35 that extends and retracts in the Z direction. The radiation source 30 is connected to the lower end of the arm 35 via a connection part 34. The upper end of the arm 35 is connected to a ceiling traveling device 36.

[0060] The radiation source 30 can move in the Y direction by the ceiling traveling device 36. The radiation generating device 11A may have an auto-tracking function that causes the height of the radiation source 30 to follow the height of the holder 42 of the imaging stand 12 by extending and retracting the arm 35.

[0061] [Second modified example] In the above embodiment, the lift control device 52 sets the initial position to the lowest position of the top plate 13A of the lift device 13, but in the second modified example, the initial position is the highest position of the top plate 13A of the lift device 13. That is, in the second modified example, the lift control device 52 controls the lift device 13 in the positioning operation in a direction to lower the lift device 13 from the initial position and in a direction to reduce the positional deviation amount D.

[0062] 9 shows lift control according to the second modified example. As described above, in the second modified example, the initial position of the lift device 13 is set to the highest position of the tabletop 13A, and therefore, the slope 60 is disposed close to the lift device 13 so that the subject H can easily get on the lift device 13. The subject H can use the slope 60 to get on the lift device 13.

[0063] If the initial position is high, when the subject H is standing on the lifting device 13, the characteristic area F will be located above the target area T, so the lifting control device 52 controls the lifting device 13 in a direction to lower the lifting device 13 from the initial position.

[0064] In this way, by setting the initial position high and controlling the lifting device 13 in a direction to lower the subject H for positioning, the subject H is positioned with his / her chin in contact with the upper part (chin rest) of the holder 42. By controlling the lifting device 13 in a direction to lower the subject H from a high position, positioning is easy with the chin rest without the assistance of the technician 24, and safety is improved.

[0065] 10 shows the procedure for positioning and imaging in the second modified example. First, the technician 24 sets the lifting device 13 to an initial position by operating the operation unit 16 (step S100). The initial position is the highest position of the tabletop 13A. After the lifting device 13 is set to the initial position, the subject H gets on to the lifting device 13 using the slope 60 (step S101). At this time, the subject H stands in an appropriate position according to the marker M on the tabletop 13A.

[0066] Next, the technician 24 operates the operation unit 16 to start positioning the subject H using the lifting device 13 (step S102). When the control device 15 receives an instruction to start positioning from the operation unit 16, it performs positioning in a direction to lower the lifting device 13 (step S103). The positioning control by the control device 15 is the same as in the above embodiment, except that the direction in which the lifting device 13 is raised and lowered is different. The positioning is completed with the chin of the subject H in contact with the upper part of the holder 42 (step S104).

[0067] When the positioning of the subject H is completed, the technician 24 operates the operation unit 16 to cause the imaging control device 50 to perform radiography (step S105). When the radiography is completed, the subject H steps down from the lifting device 13 (step S106). After confirming that the subject H has stepped down from the lifting device 13, the technician 24 operates the operation unit 16 to return the lifting device 13 to its initial position (step S107). Then, the technician 24 sterilizes the portion of the holder 42 that has been in contact with the chin of the subject H (step S108). This sterilization may be performed by a device such as an ultraviolet ray irradiation device.

[0068] Before performing radiography, the technician 24 may adjust the irradiation range based on a light field that indicates the irradiation range of radiation with light, with the subject H in a positionally aligned state. A light irradiation device for forming the light irradiation field is provided in the radiation generating device 11. The technician 24 sets an appropriate irradiation range by operating the operation unit 16 to drive the collimator 32. At this time, the technician 24 can set the irradiation range while checking the position of the irradiation range in the image P acquired by the camera 14.

[0069] 11 is an example of a light field shown in image P. The technician 24 can change the position or size of the light field A by operating the operation unit 16, and the collimator 32 is driven in conjunction with the change in the position or size of the light field A, thereby changing the position or size of the radiation irradiation range.

[0070] Note that the system may be configured to permit radiography when the position and size of the light irradiation field A in the image P are appropriate. Also, the system may be configured to issue a warning from the information output unit 17 when the body part to be photographed (e.g., the chest) registered in the imaging menu does not fall within the irradiation range as a result of adjusting the light irradiation field A.

[0071] [Third Modification] In the third modified example, the lift control device 52 detects the body movement of the subject H based on the change in the positional deviation amount D derived by the image analysis device 51 and the lifting speed of the lift device 13. Ideally, the change in the positional deviation amount D should match the lifting speed, but the body movement of the subject H causes a mismatch between the change in the positional deviation amount D and the lifting speed. The lift control device 52 detects the difference between the change in the positional deviation amount D and the lifting speed as the body movement speed.

[0072] Since it is dangerous to raise and lower the lifting device 13 when the subject H is making large body movements, the lifting control device 52 controls the lifting and lowering of the lifting device 13 based on the detected body movement speed.

[0073] Fig. 12 shows the lift control according to the third modification. The lift control according to the third modification is executed in step S15 in the flowchart shown in Fig. 7. In this modification, the lift control device 52 derives the amount of change in the positional deviation amount D (step S20). Next, the lift control device 52 derives the difference between the derived positional deviation amount D and the lift speed of the lift device 13 being controlled, and detects the difference as the body movement speed (step S21).

[0074] Next, the lift control device 52 judges whether the detected body movement speed is equal to or higher than a certain level (step S22). If the lift control device 52 judges that the body movement speed is equal to or higher than a certain level (step S22: YES), the lift control device 52 sets the lift speed of the lift device 13 to a certain value or lower (step S23). If the body movement speed is not equal to or higher than a certain level (step S23: NO), the lift control device 52 ends the lift control.

[0075] Note that keeping the lifting speed at or below a certain value in step S23 also includes stopping the lifting of the lifting device 13.

[0076] As described above, according to the third modification, when the body movement speed is equal to or higher than a certain value, the ascent / descent speed is set to a certain value or lower. Therefore, the ascent / descent speed is set to a certain value or lower until the body movement speed falls below a certain value, improving the safety of the subject H when ascending or descending the lifting device 13.

[0077] [Fourth Variation] In the fourth modified example, the lifting control device 52 stops the lifting of the lifting device 13 when it is predicted that the subject H will collide with an object based on the image P captured by the camera 14. Here, the object is an object such as an obstacle other than the subject H and the holder 42. If the subject H moves up and down while placed on the lifting device 13, there is a risk that the subject H will collide with the object if there is an object near the holder 42. Therefore, the lifting control device 52 predicts that the subject H will collide with the object and stops the lifting of the lifting device 13.

[0078] Fig. 13 shows the lift control according to the fourth modification. The lift control according to the fourth modification is executed in step S15 in the flowchart shown in Fig. 7. In this modification, the image analysis device 51 detects objects such as obstacles other than the subject H and the holder 42 based on the image P captured by the camera 14 (step S30).

[0079] The lift control device 52 judges whether or not the subject H is expected to collide with the object based on the positional relationship between the object detected by the image analysis device 51 and the subject H (step S31). If the subject H is expected to collide with the object (step S31: YES), the lift control device 52 stops the lifting of the lift device 13 (step S32). Then, the lift control device 52 issues a warning via the information output unit 17 (step S33). The warning is issued, for example, by audio output to alert the technician 24. The warning may be issued by a method such as displaying a message to alert the technician 24.

[0080] If it is not expected that the subject H will collide with an object (step S31: NO), the lift control device 52 ends the lift control.

[0081] As described above, according to the fourth modified example, it is possible to prevent the subject H from colliding with an object due to the elevation of the elevation device 13.

[0082] [Fifth Modification] In the above embodiment, the characteristic part F is the "vertebral protuberance" and the target area T is the upper side of the image P, but in the fifth modified example, the characteristic part F and the target area T are changed according to the imaging menu.

[0083] In the fifth modified example, the characteristic portion F and the target area T are set in advance for each shooting menu. For example, the control device 15 holds a setting table 70 shown in Fig. 14 as an example. The target area T is defined by its width in the Z direction and its center coordinates.

[0084] In the fifth modified example, the image analysis device 51 selects a characteristic part F and a target area T for detecting the positional deviation amount D according to the shooting menu input to the shooting control device 50. Specifically, the image analysis device 51 acquires the characteristic part F and the target area T corresponding to the shooting menu input to the shooting control device 50 from the setting table 70, and detects the positional deviation amount D using the acquired characteristic part F and target area T.

[0085] In the above embodiment and the fifth modified example, the characteristic site F is an anatomical feature of the subject H, but a marker provided on the examination gown worn by the subject H may be the characteristic site F. The marker provided on the examination gown is, for example, a pattern image that can be pattern-recognized by the image analysis device 51.

[0086] The technology of the present disclosure can be appropriately combined with the above-described embodiments and / or various modified examples. In addition, it is needless to say that the technology is not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the technology.

[0087] The above description and illustrations are detailed descriptions 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, function, action, and effect is an example of the configuration, function, action, and effect 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 description and illustrations, within the scope of the gist of the technology of the present disclosure. In addition, in order to avoid confusion and to facilitate understanding of the parts related to the technology of the present disclosure, the above description and illustrations omit explanations of technical common sense that do not require explanation in order to enable the implementation of the technology of the present disclosure.

[0088] 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. In addition, in this specification, the same idea as "A and / or B" is also applied when three or more things are expressed by connecting them with "and / or."

[0089] All publications, patent applications, and standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or standard was specifically and individually indicated to be incorporated by reference. [Explanation of symbols]

[0090] 10,10A Radiography System 11,11A Radiation Generator 12 Shooting stand 13 Lifting device 13A Top plate 14 Camera 15 Control device 16 Control section 17 Information output section 20 Radiology room 21 Control room 22 Floor 24 Engineer 30 Radiation source 31 Radiation Tube 32 Collimator 33 Stand 34 Connection 35 Arm 36 Ceiling Travel Device 40 Stand 41 Connection 42 Holder 43 Detection Panel 50 Shooting control device 51 Image analysis device 52 Lifting control device 60 Slope 70 Setting Table A light field D Position deviation F. Characteristic parts H. Subject M Marker P Image R Radiation T target area V Lifting speed

Claims

1. A radiation source that emits radiation; an imaging table having a detection panel that detects the radiation and generates a radiation image; A lifting device for placing the subject; a positional deviation amount detection device for detecting a relative positional deviation amount between the imaging platform and the subject; a lift control device that lifts and lowers the lift device based on the amount of positional deviation detected by the positional deviation detection device; Equipped with The lift control device controls a lift speed of the lift device in accordance with the positional deviation amount. Radiography system.

2. the lift control device controls the lift device in a direction to lower the lift device from an initial position and in a direction to reduce the amount of positional deviation. The radiation imaging system according to claim 1 .

3. the lift control device sets the lift speed to a high speed when the positional deviation amount is large, and sets the lift speed to a low speed when the positional deviation amount is small; 3. The radiation imaging system according to claim 1.

4. the lift control device detects a body movement of the subject based on the change in the positional deviation amount and the lift speed. The radiation imaging system according to claim 1 .

5. the lift control device detects a difference between the change in the positional deviation amount and the lift speed as a body movement speed of the subject, and when the detected body movement speed is equal to or higher than a certain value, sets the lift speed to a certain value or lower. The radiation imaging system according to claim 4 .

6. The position deviation detection device includes: a camera provided on the radiation source for photographing the subject; an image analyzer that detects the amount of positional deviation by analyzing the image acquired by the camera; Including, The radiation imaging system according to claim 1 .

7. the image analysis device detects a characteristic part of the subject from the image, and detects the amount of positional deviation based on a difference between a position of the detected characteristic part and a target area on the imaging table.

7. The radiation imaging system according to claim 6.

8. The characteristic portion is an anatomical feature of the subject or a marker on the examination gown. The radiation imaging system according to claim 7 .

9. The characteristic portion and the target area are set in advance for each imaging menu, the image analysis device selects the characteristic portion and the target area for detecting the amount of positional deviation in accordance with an imaging menu. The radiation imaging system according to claim 8 .

10. The lift control device detects a case where the subject is predicted to collide with an object based on the image. When the lifting device is stopped from lifting, The radiation imaging system according to any one of claims 6 to 9.

11. The lift control device issues a warning when it is predicted that the subject will collide with an object based on the image. The radiation imaging system according to any one of claims 6 to 10.

12. A radiation source that emits radiation; an imaging table having a detection panel that detects the radiation and generates a radiation image; A lifting device for placing the subject; a positional deviation amount detection device for detecting a relative positional deviation amount between the imaging platform and the subject; A method for controlling a radiation imaging system comprising: raising and lowering the lifting device based on the amount of positional deviation detected by the positional deviation detection device; controlling the lifting speed of the lifting device in accordance with the amount of positional deviation; A method for controlling a radiography system.

Images