X-ray imaging device

Abstract

An X-ray imaging device is provided for releasing the lock of a door arranged in a shielded room at an appropriate time. The industrial X-ray imaging device (1) comprises: an X-ray source (11); an X-ray detector (13) for detecting X-rays irradiated from the X-ray source (11); a carrier (12) arranged between the X-ray source (11) and the X-ray detector (13) and supporting a subject (BJ); and a shielded room (14) for accommodating the X-ray source (11), the X-ray detector (13) and the carrier (12), wherein the shielded room (14) comprises: a door (141) for carrying in and out the subject (BJ); and a locking mechanism (142) for prohibiting the door (141) from changing to an open state, and the X-ray imaging device (1) comprises a release control unit (16) for controlling the release of the lock of the locking mechanism (142) based on a leakage irradiation dose (LD) leaking from the shielded room (14) to the outside.

Description

Technical Field

[0001] The invention relates to an X-ray imaging device. Background Art

[0002] There is known an X-ray imaging device that uses X-rays to image the internal structure of an object to be imaged (for example, refer to Patent Document 1).

[0003] The X-ray imaging device described in Patent Document 1 includes: an X-ray source; an X-ray detector; and a transport unit disposed between the X-ray source and the X-ray detector and used to transport an object to be imaged. That is, the X-ray imaging device is configured as a so-called "industrial X-ray imaging device".

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-155561 Summary of the invention

[0007] [Problems to be solved by the invention]

[0008] However, since the photographic object is transported by the transport unit described in Patent Document 1, it is sometimes impossible to arrange the photographic object in an appropriate position or posture. In this case, a workbench for placing the photographic object is arranged instead of the transport unit. In this case, a shielded room for accommodating an X-ray source, a workbench, and an X-ray detector is arranged. In addition, a door for carrying in and out the photographic object is arranged in the shielded room.

[0009] A locking mechanism is also provided to prevent the door from changing to an open state. When the X-ray generator irradiates X-rays, the door is locked by the locking mechanism. However, no specific method is disclosed as to when to release the locking mechanism from locking the door.

[0010] If the door lock is released too late, the operator's work efficiency will be reduced. If the door lock is released too early, there is a possibility that X-rays will leak to the outside of the shield room.

[0011] An object of the present invention is to provide an X-ray imaging device capable of unlocking a door disposed in a shield room at an appropriate timing.

[0012] [Technical means to solve the problem]

[0013] An X-ray imaging device of a form of the present invention includes: an X-ray source; an X-ray detector that detects X-rays irradiated from the X-ray source; a stage that is arranged between the X-ray source and the X-ray detector and supports a photographic object; and a shielded room that accommodates the X-ray source, the X-ray detector and the stage, and in the X-ray imaging device, the shielded room includes: a door for carrying the photographic object in and out; and a locking mechanism that prohibits the door from changing to an open state, and the X-ray imaging device includes a release control unit, which controls the release of the lock of the locking mechanism based on the leakage radiation dose leaked from the shielded room to the outside.

[0014] [Effects of the Invention]

[0015] According to the X-ray imaging device of the present invention, the unlocking of the locking mechanism is controlled based on the leakage radiation dose leaking from the shielded room to the outside. Therefore, the lock of the door arranged in the shielded room can be unlocked at an appropriate time. That is, the decline in the operator's workability can be suppressed, and the leakage of X-rays to the outside of the shielded room can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a plan view showing an example of the structure of the industrial X-ray imaging device according to the present embodiment.

[0017] Figure 2 This is a diagram showing an example of the detection position of the tube voltage and the tube current.

[0018] Figure 3 This is a graph showing an example of changes in tube voltage, tube current, and leakage radiation dose when the X-ray source is turned off.

[0019] Figure 4 This is a flowchart showing an example of the processing of the release control unit.

[0020] [Explanation of Symbols]

[0021] 1: Industrial X-ray imaging device (X-ray imaging device)

[0022] 11: X-ray source

[0023] 111: X-ray tube

[0024] 112: Cathode

[0025] 113: Target

[0026] 114: First voltage source

[0027] 115: Current sensor (part of the detection unit)

[0028] 116: Voltage sensor (part of the detection unit)

[0029] 117: Second voltage source

[0030] 12: Carrier

[0031] 13: X-ray detector

[0032] 14: Shielded Room

[0033] 141: Door

[0034] 142: Locking mechanism

[0035] 15: Camera control unit

[0036] 16: Release control department

[0037] 161: Processor

[0038] 162: Storage Devices

[0039] AS: Current threshold

[0040] EL: Electronic

[0041] DL: Exposure dose limit

[0042] LD: Leakage exposure dose

[0043] RA: tube current

[0044] RS: Radiation dose threshold

[0045] RV: tube voltage

[0046] VS: Voltage Threshold

[0047] XR: X-ray DETAILED DESCRIPTION

[0048] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0049] [1. Structure of industrial X-ray imaging device]

[0050] Figure 1 It is a plan view showing an example of the structure of the industrial X-ray imaging device 1 according to the present embodiment.

[0051] like Figure 1 As shown, the industrial X-ray imaging device 1 includes an X-ray source 11 , a stage 12 , an X-ray detector 13 , an imaging control unit 15 , and a release control unit 16 .

[0052] The X-ray source 11 , the stage 12 , and the X-ray detector 13 are accommodated in a shield room 14 .

[0053] In the following description, for convenience, the industrial X-ray imaging device 1 may be described as an X-ray imaging device 1 .

[0054] The industrial X-ray imaging device 1 corresponds to an example of an “X-ray imaging device”.

[0055] The X-ray source 11 emits X-rays by supplying power from an X-ray power supply unit (not shown), and irradiates the X-rays toward the subject BJ placed on the stage 12. The X-ray source 11 applies a high voltage supplied from the X-ray power supply unit, for example, between a cathode 112 and a target 113 functioning as an anode. Then, electrons released from the cathode 112 collide with the target 113, causing the target 113 to emit X-rays.

[0056] Reference Figure 2 The cathode 112 and the target 113 are described.

[0057] The stage 12 is disposed between the X-ray source 11 and the X-ray detector 13 and is used to place the subject BJ. The stage 12 is rotatably configured by a motor or the like, for example.

[0058] The subject BJ corresponds to an example of a “photographic object”.

[0059] The X-ray detector 13 captures an image of the X-rays emitted from the X-ray source 11 and generates a captured image P. The X-ray detector 13 includes, for example, a flat panel detector (FPD). The flat panel detector includes a two-dimensional image sensor having a thin film layer including a scintillator that absorbs the energy of the X-rays and emits fluorescence formed on a light receiving surface.

[0060] The imaging control unit 15 causes the X-ray source 11 to irradiate X-rays toward the subject BJ, and acquires a captured image P of the subject BJ generated by the X-ray detector 13 .

[0061] The shield room 14 houses the X-ray source 11, the stage 12 and the X-ray detector 13 and suppresses the leakage of X-rays to the outside. The shield room 14 is provided with a door 141 for carrying in and out the subject BJ and a locking mechanism 142 for preventing the door 141 from changing from a closed state to an open state.

[0062] The locking mechanism 142 includes, for example, an electromagnetic lock. For example, when the operator instructs the generation of the captured image P, the locking mechanism 142 prohibits the door 141 from changing from the closed state to the open state. In addition, the locking mechanism 142 unlocks the door 141 according to an instruction from the unlocking control unit 16 .

[0063] The release control unit 16 instructs the lock mechanism 142 to release the lock of the door 141 based on the leakage irradiation dose LD leaking from the shield room 14 to the outside.

[0064] The release control unit 16 includes a processor 161 such as a central processing unit (CPU) or a microprocessor (MPU), and a storage device 162 such as a read only memory (ROM) or a random access memory (RAM). The storage device 162 stores a control program.

[0065] The processor 161 functions as the release control unit 16 by executing the control program in the storage device 162 .

[0066] Reference Figure 2 to Figure 4 The release control unit 16 will be described.

[0067] [2. Detection location of tube voltage and tube current]

[0068] Figure 2 It is a diagram showing an example of the detection position of the tube voltage RV and the tube current RA.

[0069] like Figure 2 As shown, the X-ray source 11 includes: an X-ray tube 111, a first voltage source 114, a current sensor 115, a voltage sensor 116 and a second voltage source 117. The X-ray tube 111 includes a cathode 112 and a target 113.

[0070] The first voltage source 114 applies a voltage between the cathode 112 and the target 113 functioning as an anode. The second voltage source 117 applies a voltage to both ends of the cathode 112 .

[0071] The electrons EL emitted from the cathode 112 are accelerated by the first voltage source 114 and collide with the target 113. As the electrons EL collide with the target 113, the target 113 emits X-rays XR.

[0072] The current sensor 115 detects the current flowing between the target 113 and the first voltage source 114 as the tube current RA. The current sensor 115 outputs a signal indicating the tube current RA to the release control unit 16 .

[0073] The voltage sensor 116 detects the voltage between both ends of the first voltage source 114 as the tube voltage RV. The voltage sensor 116 outputs a signal indicating the tube voltage RV to the release control unit 16.

[0074] The current sensor 115 and the voltage sensor 116 correspond to an example of a “detection unit”.

[0075] The release control unit 16 controls the release of the lock mechanism 142 based on the tube voltage RV and the tube current RA.

[0076] In the present embodiment, when the tube voltage RV is equal to or lower than the voltage threshold value VS and the tube current RA is equal to or lower than the current threshold value AS, the release control unit 16 releases the lock of the lock mechanism 142 .

[0077] Reference Figure 3 The voltage threshold VS and the current threshold AS are described.

[0078] [3. Voltage threshold and current threshold]

[0079] Figure 3 This is a graph showing an example of changes in the tube current RA, the tube voltage RV, and the leakage radiation dose LD when the X-ray source 11 is turned off.

[0080] Figure 3 The horizontal axes of the four graphs shown represent time T. In addition, Figure 3 The vertical axes of the four graphs shown represent, from the top, ON / OFF of the X-ray source, the tube current RA, the tube voltage RV, and the leakage irradiation dose LD.

[0081] like Figure 3 As shown in the uppermost graph G1 of FIG. 1 , at time T1 , the X-ray source 11 changes from on to off.

[0082] like Figure 3 As shown in the second graph G2 from the top, the tube current RA decreases from time T1 in a downward convex curve.

[0083] like Figure 3 As shown in the third graph G3 from the top, the tube voltage RV decreases from time T1 in a downward convex curve.

[0084] like Figure 3 As shown in the graph G4 at the bottom of the figure, the leakage irradiation dose LD decreases from time T1 in a downward convex curve. In addition, in this embodiment, the leakage irradiation dose LD shown in the graph G4 is expressed as follows: Figure 1 As shown in FIG. 1 , an irradiation dose sensor DS is arranged in the irradiation area of ​​the X-ray XR to measure the irradiation dose.

[0085] As shown in graph G4 , at time T2 , the leakage irradiation dose LD reaches the irradiation dose threshold RS, and after time T2 , the leakage irradiation dose LD monotonically decreases to below the irradiation dose threshold RS.

[0086] As shown in graph G2 , at time T2 , the tube current RA reaches the current threshold AS, and after time T2 , the tube current RA monotonically decreases to below the current threshold AS.

[0087] As shown in graph G3, at time T2, the tube voltage RV reaches the voltage threshold VS, and after time T2, the tube voltage RV monotonically drops below the voltage threshold VS.

[0088] In addition, the irradiation dose threshold RS is determined based on the exposure irradiation dose limit DL. The exposure irradiation dose limit DL will be described below.

[0089] In Japan, the "Implementation of a Ministerial Order to Amend Part of the Occupational Safety and Health Rules and the Rules for the Prevention of Damage Caused by Ionizing Radiation" dated March 30, 2001, or "Basic Law No. 253", stipulates in the "Third Detailed Matter", "Relations between Articles 3 and 3" (2) that "the effective radiation dose of workers in a year should ideally not exceed the radiation dose limit to which the general public is exposed in a year, i.e., 1 millisievert."

[0090] On the other hand, the Ionizing Radiation Damage Prevention Rules stipulate that one year is equivalent to 50 weeks, and the Japanese Labor Standards Law stipulates that working hours are 40 hours per week.

[0091] Therefore, according to the following formula (1), the exposure dose limit DL is preferably set to 0.5 μSv / Hr or less.

[0092] DL(μSv / Hr)≦1(mSv) / 50 / 40×1000(1)

[0093] In addition, Figure 3 , an example of changes in the tube voltage RV, the tube current RA, and the leakage irradiation dose LD when the X-ray source 11 is turned off is shown, but the tube voltage RV and the tube current RA are determined according to the object BJ. Therefore, in the X-ray imaging device 1, it is preferable to determine the current threshold AS, the voltage threshold VS, and the irradiation dose threshold RS based on the leakage irradiation dose LD corresponding to the tube voltage RV and the tube current RA determined according to the object BJ and the exposure irradiation dose limit DL.

[0094] [4. Processing of the release control unit]

[0095] Figure 4 This is a flowchart showing an example of the processing of the release control unit 16 .

[0096] In addition, Figure 4 In the example, the case where the current threshold AS and the voltage threshold VS are predetermined is described. Figure 4In the description, a case where the locking mechanism 142 locks the door 141 in a closed state in advance will be described.

[0097] First, in step S101 , the release control unit 16 acquires the tube current RA from the current sensor 115 .

[0098] Next, in step S103 , the release control unit 16 acquires the tube voltage RV from the voltage sensor 116 .

[0099] Next, in step S105 , the release control unit 16 determines whether the tube current RA is equal to or less than the current threshold value AS.

[0100] When the release control unit 16 determines that the tube current RA is not less than the current threshold AS (step S105; NO), the process returns to step S101. When the release control unit 16 determines that the tube current RA is less than the current threshold AS (step S105; YES), the process proceeds to step S107.

[0101] Then, in step S107 , the release control unit 16 determines whether the tube voltage RV is equal to or lower than the voltage threshold VS.

[0102] If the release control unit 16 determines that the tube voltage RV is not lower than the voltage threshold VS (step S107; No), the process returns to step S101. If the release control unit 16 determines that the tube voltage RV is lower than the voltage threshold VS (step S107; Yes), the process proceeds to step S109.

[0103] Then, in step S109, the release control unit 16 releases the lock of the lock mechanism 142. Thereafter, the process ends.

[0104] In this way, when the tube current RA is less than the current threshold AS and the tube voltage RV is less than the voltage threshold VS, the release control unit 16 releases the lock of the lock mechanism 142. Therefore, by appropriately setting the current threshold AS and the voltage threshold VS, the door 141 can be released at an appropriate timing. That is, the decline in the operator's workability can be suppressed, and the leakage of X-rays to the outside of the shield room can be suppressed.

[0105] [5. Implementation form and effect]

[0106] Those skilled in the art will understand that the above-described embodiments are specific examples of the following embodiments.

[0107] (First Item)

[0108] One form of an X-ray imaging device includes: an X-ray source; an X-ray detector that detects X-rays irradiated from the X-ray source; a stage that is arranged between the X-ray source and the X-ray detector and supports a photographic object; and a shielded room that accommodates the X-ray source, the X-ray detector and the stage, and in the X-ray imaging device, the shielded room includes: a door for carrying the photographic object in and out; and a locking mechanism that prohibits the door from changing to an open state, and the X-ray imaging device includes a release control unit, which controls the release of the locking mechanism based on the leakage radiation dose leaked from the shielded room to the outside.

[0109] According to the X-ray imaging device described in the first aspect, the release control unit controls the release of the lock of the lock mechanism based on the leakage irradiation dose.

[0110] Therefore, the lock of the locking mechanism can be released at an appropriate timing. That is, it is possible to suppress a decrease in the operator's workability and to suppress leakage of X-rays to the outside of the shield room.

[0111] (Second Item)

[0112] The X-ray imaging device according to the first item further includes a detection unit that detects a tube voltage of the X-ray source and a tube current of the X-ray source, and the release control unit controls the release of the lock of the locking mechanism based on at least one of the tube voltage and the tube current.

[0113] In the X-ray imaging device according to the second aspect, the release control unit controls the release of the lock of the lock mechanism based on at least one of the tube voltage and the tube current.

[0114] Therefore, the lock of the locking mechanism can be released at an appropriate timing. That is, it is possible to suppress a decrease in the operator's workability and to suppress leakage of X-rays to the outside of the shield room.

[0115] (Third Item)

[0116] The X-ray imaging device according to item 2, wherein the release control unit releases the lock of the lock mechanism when the tube voltage is equal to or less than a voltage threshold and the tube current is equal to or less than a current threshold.

[0117] According to the X-ray imaging device according to item 3, when the tube voltage is equal to or less than a voltage threshold and the tube current is equal to or less than a current threshold, the release control unit releases the lock of the lock mechanism.

[0118] Therefore, by setting the voltage threshold and the current threshold to appropriate values, the lock of the lock mechanism can be released at an appropriate timing. That is, it is possible to suppress a decrease in the operator's workability and suppress the leakage of X-rays to the outside of the shield room.

[0119] (4th item)

[0120] The X-ray imaging device according to item 3, wherein the voltage threshold and the current threshold are set so that the leakage irradiation dose becomes equal to or less than an irradiation dose threshold.

[0121] According to the X-ray imaging device described in the fourth aspect, the voltage threshold and the current threshold are set so that the leakage irradiation dose becomes equal to or less than an irradiation dose threshold.

[0122] Therefore, by setting the irradiation dose threshold to an appropriate value, the voltage threshold and the current threshold can be set to appropriate values. Therefore, the locking mechanism can be unlocked at an appropriate time. That is, the decline in the operator's workability can be suppressed, and the leakage of X-rays to the outside of the shielding room can be suppressed.

[0123] (Fifth Item)

[0124] The X-ray imaging device according to item 4, wherein the irradiation dose threshold is determined based on an exposure irradiation dose limit.

[0125] According to the X-ray imaging device described in the fifth item, the irradiation dose threshold is determined based on the exposure irradiation dose limit.

[0126] Therefore, the irradiation dose threshold can be set to an appropriate value. Therefore, the voltage threshold and the current threshold can be set to appropriate values. As a result, the lock of the locking mechanism can be released at an appropriate time. That is, the decline in the operator's workability can be suppressed, and the leakage of X-rays to the outside of the shielding room can be suppressed.

[0127] [6. Other embodiments]

[0128] In addition, the industrial X-ray imaging device 1 of the present embodiment is ultimately an example of a form of "X-ray imaging device", and can be arbitrarily modified and applied within the scope not departing from the gist of the present invention.

[0129] In the present embodiment, a case where one door 141 is disposed in the shield room 14 is described, but the present invention is not limited to this. A plurality of doors may be disposed in the shield room 14 .

[0130] In the present embodiment, the locking mechanism 142 is described as including an electromagnetic lock, but the present invention is not limited thereto. The locking mechanism 142 only needs to unlock the door 141 in accordance with an instruction from the unlocking control unit 16 .

[0131] In the present embodiment, the release control unit 16 controls the release of the lock mechanism 142 based on the tube voltage RV and the tube current RA, but the present invention is not limited thereto. The release control unit 16 only needs to control the release of the lock mechanism 142 based on at least one of the tube voltage RV and the tube current RA.

[0132] In the present embodiment, when the tube current RA is less than the current threshold AS and the tube voltage RV is less than the voltage threshold VS, the release control unit 16 releases the lock of the lock mechanism 142, but the present invention is not limited thereto. For example, when the following formula (2) is satisfied, the release control unit 16 may release the lock of the lock mechanism 142.

[0133] F(RA, RV) ≤ FS(2)

[0134] The function F(RA, RV) is a function of the tube current RA and the tube voltage RV, and the function threshold FS defines a condition for the release control unit 16 to release the lock of the lock mechanism 142 .

[0135] In addition, as the function F(RA, RV), for example, the following formula (3) is preferable.

[0136] F(RA, RV) = RA n ×RV (3)

[0137] The power n is, for example, 2 to 4.

[0138] In the present embodiment, the release control unit 16 and the camera control unit 15 are configured as separate bodies, but the present invention is not limited thereto. The release control unit 16 may be configured as a single body with the camera control unit 15. That is, the processor 161 may also function as the release control unit 16 and the camera control unit 15 by executing the control program stored in the storage device.

[0139] in addition, Figure 1 The functional units shown represent functional structures, and there is no particular limitation on the specific installation form. That is, it is not necessary to install hardware corresponding to each functional unit, and it is also possible to set a structure in which the functions of multiple functional units are realized by executing a program by one processor. In addition, in the above-mentioned embodiments, a part of the functions realized by software can be realized by hardware, or a part of the functions realized by hardware can be realized by software.

[0140] In order to facilitate understanding of the processing of the release control unit 16, Figure 4 The processing units in the flowchart shown are divided according to the main processing contents. Figure 4The division method or name restriction of the processing unit shown in the flowchart can be divided into more processing units according to the processing content, or one processing unit can be divided into more processing units. In addition, the processing order of the flowchart is not limited to the example shown in the figure.

[0141] in addition, Figure 1 The release control unit 16 shown can be implemented by causing the processor 161 included in the release control unit 16 to execute a control program. In addition, the control program can also be recorded in a recording medium recorded in a computer-readable manner. As a recording medium, a magnetic, optical recording medium or a semiconductor memory device can be used. Specifically, portable or fixed recording media such as a floppy disk, HDD, compact disk read only memory (CD-ROM), digital versatile disc (DVD), Blu-ray (Blu-ray) (registered trademark) disc (Disc), optical magneto-magnetic disk, flash memory, card-type recording medium, etc. can be listed. In addition, the recording medium can also be an internal storage device included in the release control unit 16, that is, a non-volatile storage device such as RAM, ROM, HDD, etc. In addition, the control program can also be stored in a server device, etc., and the control program can be downloaded from the server device to the release control unit 16.

Claims

1. An X-ray imaging device, characterized in that: include: X-ray source; An X-ray detector for detecting X-rays emitted from the X-ray source; a stage, arranged between the X-ray source and the X-ray detector and supporting an object to be photographed; and a shielding room accommodating the X-ray source, the X-ray detector and the stage, and in the X-ray imaging device, The shielding room includes: a door for carrying in and out the photographic object; and a locking mechanism that prohibits the door from changing to an open state, The X-ray imaging device includes a release control unit configured to control the release of the lock of the lock mechanism based on a leakage radiation dose leaking from the shield room to the outside. The X-ray imaging device further includes a detection unit, The detection unit detects the tube voltage of the X-ray source and the tube current of the X-ray source. The release control unit controls the release of the lock mechanism based on at least one of the tube voltage and the tube current.

2. The X-ray imaging device according to claim 1, characterized in that: The release control unit releases the lock of the lock mechanism when the tube voltage is equal to or less than a voltage threshold and the tube current is equal to or less than a current threshold.

3. The X-ray imaging device according to claim 2, characterized in that: The voltage threshold and the current threshold are set so that the leakage irradiation dose becomes equal to or less than an irradiation dose threshold.

4. The X-ray imaging device according to claim 3, characterized in that: The radiation dose threshold is determined based on the exposure radiation dose limit.

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