Radiation shielding plate

Abstract

This radiation blocking plate (1) comprises: a first plate member (10) that is formed of a radiation blocking material for blocking radiation, and that is installed on a floor surface (F), with a principle surface (10a) facing a front / back direction; a second plate member (20) that is formed of a radiation blocking material for blocking radiation, that is provided at a higher position than the first plate member (10), with a principle surface (20a) facing in the front / back direction; and a middle member (30) that is formed of a radiation blocking material for blocking radiation, that is provided between the first panel member (10) and the second panel member (20), that includes a narrow part (31) having a right / left direction width smaller than the right / left direction width of the first plate member (10) and of the second plate member (20), and that includes an opening part (32) which is provided at least on one side, in the right / left direction, of the narrow part (31), and which opens in the front / back direction.

Description

[Technical Field]

[0001] The present invention relates to a radiation shielding plate. This application claims priority to Japanese Patent Application No. 2020-207647, filed on December 15, 2020, the contents of which are incorporated herein by reference. [Background technology]

[0002] Patent Document 1 discloses a radiation shielding plate used as a shielding plate for radiation from a radiation source (ray source). In facilities of medical institutions that handle radiation, plates having radiation shielding properties are used as wall materials etc. to protect the human body from exposure. Specifically, radiation shielding plates are sometimes used in surgeries that use radiographic devices (radiation devices). Radiation shielding plates are installed between the radiation device and medical staff such as doctors, nurses, and radiological technologists. Radiation shielding plates block the radiation emitted from the source of the radiation device, protecting the medical staff from exposure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-155806 Summary of the Invention [Problem to be solved by the invention]

[0004] The radiation source of the radiation device is installed near the patient who is being irradiated with radiation. Therefore, the radiation shielding panel is installed between the patient and the medical staff. This means that the medical staff has to work through the radiation shielding panel, for example by leaning half their body towards the patient, which makes it difficult to work. When working without using a radiation shield, increased radiation exposure becomes a problem. Therefore, the radiation shielding plates of the prior art have room for improvement in terms of protecting the human body from radiation exposure while maintaining workability.

[0005] Therefore, the present invention provides a radiation shielding plate that can protect the human body from radiation exposure while maintaining workability. [Means for solving the problem]

[0006] In order to achieve the above object, the radiation shielding plate of the present invention comprises: a first plate portion formed of a radiation-shielding material that shields radiation and placed on a floor surface with its main surface facing in the front-to-rear direction; a second plate portion formed of a radiation-shielding material that shields radiation and placed above the first plate portion with its main surface facing in the front-to-rear direction, and having a transparent portion that is optically transparent; and an intermediate portion formed of a radiation-shielding material that shields radiation and placed between the first plate portion and the second plate portion, and having a narrow portion whose width in the left-to-right direction is narrower than the width of the first plate portion and the second plate portion, and an opening portion that is located at least laterally than the narrow portion and opens in the front-to-rear direction.

[0007] In the radiation shielding plate of the above aspect, the radiation shielding material may contain lead.

[0008] In the radiation shielding plate of the above aspect, the middle portion may be provided with a door portion that can open and close the opening portion.

[0009] In the radiation shielding plate of the above aspect, the door portion may be provided at the left and right ends of the narrow width portion so as to be rotatable in the front-rear direction around an axis extending in the left-right direction.

[0010] In the radiation shielding plate of the above aspect, the opening and the door portion may have a width in the left-right direction of 200 mm or more and 300 mm or less.

[0011] The radiation shielding plate of the above aspect may further include an accessory plate that is fitted into the opening with its main surface facing the front-rear direction and is detachable from the opening.

[0012] In the radiation shielding plate of the above aspect, the accessory plate may have a small opening that opens in the front-rear direction.

[0013] In the radiation shielding plate of the above aspect, the intermediate portion may have a table that is rotatable in the front-rear direction around an axis along the left-right direction and is movable between an installed state in which the main surface faces in the up-down direction and a stored state in which the main surface faces in the front-rear direction.

[0014] In the radiation shielding plate of the above aspect, the vertical middle portion of the opening may be provided in a range of 900 mm to 1200 mm above the floor surface.

[0015] In the radiation shielding plate of the above aspect, the openings may be provided as a pair in the left and right direction with the narrow portion therebetween, and the pair of openings may be formed asymmetrically. [Effects of the Invention]

[0016] According to each of the above aspects, it is possible to maintain workability while protecting the human body from radiation exposure. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a layout diagram of a medical system including a radiation shielding plate according to a first embodiment. [Figure 2] FIG. 2 is a rear view of the radiation shielding plate according to the first embodiment. [Figure 3] FIG. 2 is a right side view of the radiation shielding plate according to the first embodiment. [Figure 4] FIG. 2 is a top view of the radiation shielding plate according to the first embodiment. [Figure 5] FIG. 2 is a perspective view showing a simulation model for confirming the radiation shielding performance of the radiation shielding plate according to the first embodiment. [Figure 6] FIG. 6 is a front view of the model of the radiation shielding plate in FIG. 5 as seen from the patient side. [Figure 7] 10 is a graph comparing the average relative dose to the lens at the first setting for each aperture size. [Figure 8] 1 is a graph comparing the average relative dose to the thyroid gland for each aperture size in the first setting. [Figure 9] 1 is a graph comparing the average relative dose to the ovary for each opening size in the first setting. [Figure 10] 10 is a graph comparing the exposure distribution of the human body for each size of opening in the first setting. [Figure 11] 10 is a graph comparing the average relative dose to the lens for each aperture size in the second setting. [Figure 12] 10 is a graph comparing the average relative dose to the thyroid gland for each aperture size in the second setting. [Figure 13] This is a graph comparing the average relative dose to the ovary in the second setting by opening size. [Figure 14] 10 is a graph comparing the exposure distribution of the human body for each size of the opening in the second setting. [Figure 15] FIG. 10 is a rear view of the radiation shielding plate according to the second embodiment. [Figure 16] FIG. 10 is a perspective view showing a simulation model for confirming the radiation shielding performance of the radiation shielding plate according to the second embodiment. [Figure 17] FIG. 17 is a diagram showing the simulation model of FIG. 16 as viewed from above. [Figure 18] 1 is a graph showing the relative absorbed dose in the lens of an ultrasound surgeon. [Figure 19] 1 is a graph showing the relative absorbed dose to the thyroid of an ultrasound surgeon. [Figure 20] 1 is a graph showing the relative absorbed dose to the ovaries of ultrasound surgeons. [Figure 21] 1 is a graph showing the relative absorbed dose in the crystalline lens of an anesthesiologist. [Figure 22] 1 is a graph showing the relative absorbed dose to the thyroid of an anesthesiologist. [Figure 23] 1 is a graph showing the relative absorbed dose to the ovaries of anesthesiologists. [Figure 24] 1 is a graph showing the relative skin absorbed dose distribution of an ultrasound surgeon. [Figure 25] 1 is a graph showing the relative skin absorbed dose distribution of an anesthesiologist. DETAILED DESCRIPTION OF THE INVENTION

[0018] First Embodiment A radiation shielding plate 1 according to a first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a layout diagram of a medical system 100 including a radiation shielding plate 1. Fig. 1 shows the layout of the medical system 100 as viewed from above. The medical system 100 shown in Fig. 1 is used for catheter surgery. The medical system 100 includes an operating table 101, a monitor 104, a radiation device 110, an anesthesia machine 102, an ultrasound device 103, and a radiation shielding plate 1.

[0019] The operating table 101 is formed in a rectangular shape extending in one direction when viewed from above. Patient A, who will undergo surgery, lies supine on the operating table 101. Patient A's head is located at one end of the operating table 101. Patient A's feet are located at the other end of the operating table 101. A monitor 104, a radiation device 110, an anesthesia machine 102, an ultrasound device 103, and a radiation shielding plate 1 are installed around the operating table 101. The monitor 104 is placed on the left side of the patient A. The radiation device 110 displays an in-vivo image on the monitor 104 for guiding a catheter into the body of patient A. The radiation device 110 has a radiation source 111, an arm 112, and an image receptor 113. The radiation source 111 is installed below the operating table 101. The radiation source 111 emits radiation toward patient A. The radiation emitted from the radiation source 111 is X-rays. The arm 112 extends from a main body (not shown) of the radiation device 110 installed on the left side of patient A toward above patient A. The image receptor 113 is supported by the arm 112 above patient A. The image receptor 113 is supported by the arm 112 so as to be movable around patient A. The image receptor 113 receives X-rays from the radiation source 111 that have passed through patient A, and transmits information about the in-vivo image of patient A to the monitor 104. The monitor 104 displays an image of the inside of the patient A based on information from the image receiver 113 . The anesthesia machine 102 is placed on the right side of the patient A, close to the head. The ultrasound device 103 is placed on the left side of the patient A, close to the head.

[0020] Around the operating table 101, medical professionals B, such as a surgeon (not shown), a radiological technologist (not shown), anesthesiologist B1, and ultrasound surgeon B2, stand. Anesthesiologist B1 stands at the head side of patient A. Anesthesiologist B1 manages anesthesia for patient A by operating an anesthesia machine 102. Ultrasound surgeon B4 operates, for example, an ultrasound device 103 to display an image of the inside of patient A's body as a catheter is passed through.

[0021] (Radiation shielding plate) The radiation shielding plate 1 is placed between the patient A and the anesthesiologist B1 and ultrasound surgeon B2. FIG. 2 is a rear view of the radiation shielding plate 1. As shown in FIG. 2, the radiation shielding plate 1 is installed on a floor surface F. The radiation shielding plate 1 extends upward from the floor surface F. The height direction of the radiation shielding plate 1, which is the vertical direction of gravity, is hereinafter defined as the "vertical direction." The front-to-back direction and left-to-right direction when the anesthesiologist B1 and the ultrasound surgeon B2 view the radiation shielding plate 1 are hereinafter defined as the "front-to-back direction" and the "left-to-right direction," respectively. In the drawings used in the following explanation, the arrow UP indicates upward, the arrow FR indicates forward, and the arrow LH indicates left. The radiation shielding plate 1 is installed with its rear surface facing the anesthesiologist B1 and ultrasound surgeon B2, and its front surface facing the patient A. When viewed from the front-to-back direction, the radiation shielding plate 1 is formed in a rectangular shape with long sides extending in the up-down direction and short sides extending in the left-to-right direction. The height of the radiation shielding plate 1 in the up-down direction is, for example, 1900 mm.

[0022] FIG. 3 is a right side view of the radiation shielding plate 1. As shown in FIG. FIG. 4 is a top view of the radiation shielding plate 1. As shown in FIG. As shown in FIGS. 2 to 4, the radiation shielding plate 1 includes a first plate portion 10, a second plate portion 20, a middle portion 30, a rail 2, and a hook 3. (1st plate part) The first plate 10 is formed in a rectangular shape with long sides along the up-down direction and short sides along the left-right direction when viewed from the front-to-rear direction. The first plate 10 is placed on a floor surface F with its main surface 10a facing the front-to-rear direction. The height of the first plate 10 in the up-down direction is, for example, 900 mm. The width of the first plate 10 in the left-to-right direction is, for example, 850 mm. The first plate 10 is formed from a radiation-shielding material that blocks radiation. The radiation-shielding material forming the first plate 10 contains lead. The first plate 10 has legs 11, a first plate main body 12, and a first frame 13.

[0023] The leg 11 is placed on a floor surface F. The leg 11 has a leg body 14, a support leg 15, and a caster 16. The leg body 14 is formed in a rectangular shape with long sides extending in the left-right direction and short sides extending in the up-down direction when viewed from the front-to-back direction. The main surface of the leg body 14 faces in the front-to-back direction. The leg body 14 is spaced apart from the floor F.

[0024] The support leg 15 is provided at the vertical middle portion of the leg main body 14. A pair of support legs 15 are provided spaced apart in the left-right direction. The support legs 15 extend in the front-rear direction. The support legs 15 include a rear support leg 15a and a front support leg 15b. The rear support leg 15a extends rearward from the leg main body 14. The length of the rear support leg 15a in the front-rear direction is, for example, 300 mm. The lower edge of the rear support leg 15a is aligned with the floor surface F. The upper edge of the rear support leg 15a is inclined downward as it extends rearward from the leg main body 14 when viewed from the left-right direction. The front support leg 15b overlaps with the rear support leg 15a in the front-rear direction. The front support leg 15b extends forward from the leg main body 14. The length of the front support leg 15b in the front-rear direction is, for example, 285 mm. The lower edge of the front support leg 15b is aligned with the floor surface F. The upper edge of the front support leg 15b is inclined downward from the leg body 14 toward the front when viewed from the left and right. The casters 16 are provided one at each end in the front-rear direction of the support leg 15. The casters 16 are disposed between the support leg 15 and the floor surface F.

[0025] The first plate body 12 is located higher than the leg body 14. When viewed from the front-to-rear direction, the first plate body 12 is formed in a rectangular shape with long sides along the left-right direction and short sides along the up-down direction. The lower edge of the first plate body 12 is connected to the upper edge of the leg body 14. The left-to-right width of the first plate body 12 is equal to the left-to-right width of the leg body 14. The front-to-rear thickness of the first plate body 12 is equal to the front-to-rear thickness of the leg body 14. The main surface of the first plate body 12 faces in the front-to-rear direction. The main surface of the first plate body 12 is flush with the main surface of the leg body 14. The first frame 13 is formed in a U-shape that opens downward when viewed from the front-to-rear direction. The first frame 13 covers both left and right end edges of the leg main body 14 from the left and right sides. The first frame 13 covers the upper end edge of the first plate main body 12 from above, and also covers both left and right end edges of the first plate main body 12 from the left and right sides.

[0026] (Second board part) The second plate portion 20 is formed in a rectangular shape with long sides along the left-right direction and short sides along the up-down direction when viewed from the front-rear direction. The second plate portion 20 is provided above the first plate portion 10 with a gap therebetween, with its main surface 20a facing in the front-rear direction. The height of the second plate portion 20 in the up-down direction is, for example, 700 mm. The width of the second plate portion 20 in the left-right direction is, for example, 850 mm. The thickness of the second plate portion 20 in the front-rear direction is equal to the thickness of the first plate portion 10 in the front-rear direction. The left-right middle portion of the second plate portion 20 is located at the same position in the left-right direction as the left-right middle portion of the first plate portion 10. The main surface 20a of the second plate portion 20 faces in the front-rear direction. The main surface 20a of the second plate portion 20 is flush with the main surface 10a of the first plate portion 10. The second plate portion 20 is formed of a radiation-shielding material that blocks radiation. The radiation shielding material forming the second plate portion 20 contains lead. The second plate portion 20 has a second plate portion main body 21 and a second frame 22.

[0027] The second plate body 21 is formed in a rectangular shape with long sides along the left-right direction and short sides along the up-down direction when viewed from the front-rear direction. The main surface of the second plate body 21 faces the front-rear direction. The second plate body 21 is made of a radiation shielding material. Specifically, the second plate body 21 is made of lead-containing glass. The second frame 22 is formed in a U-shape that opens upward when viewed from the front-to-rear direction. The second frame 22 covers the lower edge of the second plate main body 21 from below and also covers both left and right end edges of the second plate main body 21 from both left and right directions. The portion of the second plate main body 21 that is more inward than the second frame 22 is a light-transmitting portion 23.

[0028] (middle part) The intermediate portion 30 is provided between the first plate portion 10 and the second plate portion 20. The intermediate portion 30 is formed of a radiation-shielding material that blocks radiation. The radiation-shielding material that forms the intermediate portion 30 contains lead. The intermediate portion 30 has a narrow portion 31, an opening 32, a table 33, and a door portion 34.

[0029] The narrow portion 31 is formed in a rectangular shape with long sides along the left-right direction and short sides along the up-down direction when viewed from the front-rear direction. The lower edge of the narrow portion 31 is connected to the upper edge of the first plate portion 10. The upper edge of the narrow portion 31 is connected to the lower edge of the second plate portion 20. The height of the narrow portion 31 in the up-down direction is, for example, 300 mm. The width of the narrow portion 31 in the left-right direction is, for example, 450 mm. The left-right middle portion of the narrow portion 31 is located at the same position in the left-right direction as the left-right middle portions of the first plate portion 10 and the second plate portion 20. The thickness of the narrow portion 31 in the front-rear direction is equal to the thickness of the first plate portion 10 and the second plate portion 20 in the front-rear direction. The main surface 31a of the narrow portion 31 faces in the front-rear direction. The main surface 31 a of the narrow width portion 31 is flush with the main surface 10 a of the first plate portion 10 and the main surface 20 a of the second plate portion 20 .

[0030] A pair of openings 32 are provided outside the narrow portion 31 in the left-right direction. The openings 32 are formed by the outer left-right edges of the narrow portion 31, the upper edge of the first plate portion 10, and the lower edge of the second plate portion 20. The openings 32 are open in the front-rear direction and also open outward in the left-right direction. The vertical height L1 of the openings 32 is, for example, 300 mm. The vertical height L1 of the openings 32 is preferably 200 mm or more and 400 mm or less. This allows medical worker B to easily extend only his or her arm toward the radiation source 111 through the openings 32, compared to when the vertical height L1 of the openings 32 is narrower than 200 mm. The radiation shielding plate 1 can better protect medical worker B from radiation exposure, compared to when the vertical height L1 of the openings 32 is wider than 400 mm. Therefore, medical worker B can perform work closer to the radiation source 111 than the radiation shielding plate 1 while being well protected from radiation exposure by the radiation shielding plate 1. Therefore, the radiation shielding plate 1 can maintain workability while well protecting the body of medical worker B from radiation exposure. The width L2 in the left-right direction of the opening 32 is, for example, 200 mm. It is desirable that the width L2 in the left-right direction of the opening 32 be 200 mm or more and 300 mm or less. The middle part of the opening 32 in the up-down direction is located 1050 mm above the floor surface F. The table 33 is provided at a position corresponding to the narrow portion 31 in the left-right direction. The table 33 is formed in a flat plate shape. The table 33 can be moved between an installed state P1 in which the main surface faces in the up-down direction and a stored state P2 in which the main surface faces in the front-rear direction. In the installed state P1, the table 33 protrudes rearward from the narrow portion 31. In the installed state P1, the table 33 can be used to place tools required for work. In the storage state P2, the table 33 overlaps in the front-rear direction with the narrow width portion 31. In the storage state P2, the table 33 is formed in the same rectangular shape as the narrow width portion 31 when viewed in the front-rear direction. The table 33 is connected to the narrow portion 31 by a first hinge 35 so as to be rotatable about an axis O that runs along the upper edge of the rear surface of the first plate portion 10. Three first hinges 35 are provided between the narrow portion 31 and the table 33, spaced equally apart in the left-right direction. The table 33 can be moved between an installed state P1 and a stored state P2 by rotating in the front-to-rear direction around the axis O.

[0031] A pair of door sections 34 are provided outside the narrow width section 31 in the left-right direction. The door sections 34 are provided at positions corresponding to the openings 32 in the left-right direction. The door sections 34 are formed in a flat plate shape. The door sections 34 are capable of transitioning between an open state in which the openings 32 are open and a closed state in which the openings 32 are closed. In the open state, the door portion 34 protrudes rearward from the first plate portion 10. In the open state, the door portion 34 allows the medical worker B to insert his / her arm into the opening 32. In the open state, the door portion 34 is aligned in the left-right direction with the table 33 in the installation state P1. In the open state, the main surface of the door portion 34 is flush with the main surface of the table 33 in the installation state P1. In the closed state, the door section 34 overlaps with the opening 32 in the front-to-rear direction. When viewed from the front-to-rear direction, the door section 34 is formed in the same rectangular shape as the opening 32 in the closed state. The vertical height of the door section 34 is, for example, 300 mm. The vertical height of the door section 34 is preferably 200 mm or more and 400 mm or less. It is more preferably 300 mm. In this embodiment, the vertical height of the door section 34 is 300 mm, which is the same as the vertical height L1 of the opening 32. This allows the door section 34 to block the entire vertical area of ​​the opening 32. By blocking the opening 32 when not working, medical worker B can be effectively shielded from radiation. Therefore, medical worker B can be effectively protected from radiation exposure even when not working. The left-to-right width of the door section 34 is, for example, 200 mm. The left-right width of the door portion 34 is preferably 200 mm or more and 300 mm or less. It is even more preferable that the left-right width of the door portion 34 is 200 mm. In the closed state, the door portion 34 is aligned left-right with the table 33 in the storage state P2. In the closed state, the main surface of the door portion 34 is flush with the main surface of the table 33 in the storage state P2. The door portion 34 is connected to the opening 32 by a second hinge 36 so as to be rotatable about an axis O. Two second hinges 36 are provided side by side at equal intervals in the left-right direction between the first plate portion 10 and the door portion 34. The door portion 34 can be moved between an open state and a closed state by rotating in the front-to-rear direction about the axis O.

[0032] A pair of rails 2 are provided on both left and right end edges of the first plate portion 10. The rails 2 are provided above the middle portion of the first plate portion 10 in the up-down direction. The rail 2 has a rail main body 2b and a rail mounting portion 2a. The rail main body 2b is spaced outward in the left-right direction from the first plate portion 10. The rail main body 2b is a rod-shaped member that extends in the up-down direction. The rail mounting portion 2a is provided between the rail main body 2b and the first plate portion 10. The rail mounting portion 2a is provided in pair and spaced apart in the up-down direction. The rail mounting portion 2a connects the rail main body 2b and the first plate portion 10. The rail 2 is used to guide the operating table 101. A pair of hooks 3 are provided on both left and right edges of the second plate portion 20. The hooks 3 are provided on the upper end of the second plate portion 20. The hooks 3 are rod-shaped members that extend outward in the left and right directions from the second plate portion 20. The tip of the hook 3 is formed into a U-shape that opens upward when viewed from the front and back direction. The hooks 3 are used to hang an IV drip or the like.

[0033] (Simulation of radiation shielding) A simulation of the radiation shielding plate 1 will be described below. The simulation was performed to confirm the change in the shielding performance of the radiation shielding plate 1 due to a change in the size of the opening 32. Specifically, the simulation was performed to confirm the change in the radiation dose to which the lens of the eye, the thyroid gland, and the ovaries, which are located on the face, neck, and lower abdomen, respectively, of medical worker B are exposed. The lens, thyroid gland, and ovaries are all organs that pose a high risk from radiation exposure. FIG. 5 is a perspective view showing a simulation model for confirming the radiation shielding performance of the radiation shielding plate 1. As shown in FIG. In the simulation shown in Fig. 5, models corresponding to the operating table 101, radiation source 111, image receptor 113, and radiation shielding plate 1 of the medical system 100 are installed. A model of patient A is lying supine on the model of the operating table 101. A model of medical worker B is placed behind the model of radiation shielding plate 1 (on the opposite side of the radiation shielding plate 1 from patient A). In the simulation, the components described in the above embodiment, and the models corresponding to the patient A and medical worker B are denoted by the same reference numerals as in the above embodiment for convenience.

[0034] FIG. 6 is a front view of the model of the radiation shielding plate 1 in FIG. 5 as seen from the patient A side. As shown in FIGS. 5 and 6, the model of the radiation shielding plate 1 is a simple flat plate-like model that does not have the support legs 15, the casters 16, the table 33, and the door portion . The model of the radiation shielding plate 1 is set as a plate made of lead and having a thickness of 1 mm in the front-to-rear direction. In the simulation, the height of the opening 32 in the up-down direction is set as L1, and the width of the opening 32 in the left-to-right direction is set as L2. In the simulation, the height L1 and width L2 of the pair of openings 32 are changed. Hereinafter, the vertical change in height L1 is defined as H, with the vertical midpoint C1 of opening 32 when height L1 = 300 mm as the reference point. For example, when the change is H0, height L1 of opening 32 = 300 mm. When the change is H100, H50, H-50, or H-100, height L1 of opening 32 = 400 mm, 350 mm, 250 mm, or 200 mm, respectively. Hereinafter, the amount of change in width L2 in the left-right direction is defined as W, with the position C2 of the inner left-right edge of opening 32 when width L2 = 200 mm as the reference point. For example, when the amount of change is W0, width L2 of opening 32 = 200 mm. When the amounts of change are W100, W50, W-50, and W-100, width L2 of opening 32 = 300 mm, 250 mm, 150 mm, and 100 mm, respectively.

[0035] When viewed from the front-to-back direction, medical worker B stands on floor surface F so as to be positioned inside the left-to-right direction of narrow portion 31. When the variation amounts are H0 and W0, both arms of medical worker B are positioned slightly inside the left-to-right direction of the outer ends of narrow portion 31. Using the above model, a Monte Carlo simulation was performed. The parameters of this simulation are shown in Table 1.

[0036] [Table 1]

[0037] Below, based on Table 1, each parameter (parameter in Table 1) of this simulation and its setting value will be explained. (kV) is the tube voltage of the radiation source 111 and indicates the X-ray energy of the radiation source 111. The tube voltage is 72 kV. (mA) is the tube current of the radiation source 111 and indicates the X-ray dose of the radiation source 111. The tube current is 4.0 mA. (Field of view) indicates the X-ray irradiation area on the image receiving surface of the image receptor 113. The X-ray irradiation area is indicated by the length of one side of the X-ray irradiation area 113a when the X-ray irradiation area 113a on the image receiving surface of the image receptor 113 is assumed to be a square. The X-ray irradiation area is 19 inches.

[0038] (Frames per second) indicates the number of frames (number of shots taken per second). The number of frames is 3.75. (Source to surface distance) indicates the distance L3 in the PA (Posterior Anterior) direction from the radiation source 111 to the skin surface of patient A. The PA direction is the direction from the back of patient A to the chest. In this simulation, the PA direction coincides with the direction from below to above. The distance L3 is 62 cm in the PA direction.

[0039] (Source to image-receptor distance) indicates the distance L4 from the radiation source 111 to the image receptor 113. The distance L4 can be set to 98 cm (LAO16 CRA13) or 107 cm (RAO9 CAU1). LAO16 means that the image receptor 113 is positioned at a tilt of 16° to the left of patient A from the PA direction. CRA13 means that the image receptor 113 is positioned at a tilt of 13° toward the head of patient A from the PA direction. RAO9 means that the image receptor 113 is positioned at a tilt of 9° to the right of patient A from the PA direction. CAU1 means that the image receptor 113 is positioned at a tilt of 1° toward the feet of patient A from the PA direction. Hereinafter, the case where the distance L4 is set to 98 cm (LAO16 CRA13) will be referred to as the first setting, and the case where the distance L4 is set to 107 cm (RAO9 CAU1) will be referred to as the second setting.

[0040] (Filter) indicates an additional filter (not shown) used in the radiation device 110. The additional filter changes the radiation quality of the X-rays and reduces the radiation dose to which patient A is exposed. In this simulation, aluminum with a thickness of 2.5 mm, copper with a thickness of 0.4 mm, and aluminum with a thickness of 1.00 mm are used as the additional filters.

[0041] Below, we will explain the results of the simulation performed with the first setting (L4 = 98 cm (LAO16 CRA13)). FIG. 7 is a graph comparing the average relative dose to the crystalline lens at the first setting for each size of the opening 32. FIG. 8 is a graph comparing the average relative dose to the thyroid gland for each size of the opening 32 in the first setting. FIG. 9 is a graph comparing the average relative dose to the ovaries for each size of the opening 32 in the first setting.

[0042] 7 to 9 show the average relative doses in the lens, thyroid, and ovaries of medical worker B, respectively. In FIGS. 7 to 9, the vertical axis represents the average relative dose, and the horizontal axis represents the change H in height L1 at the opening 32. The average relative dose is a relative value when the average dose to which medical worker B is exposed when the radiation shielding plate 1 is not installed is set to 1. In FIGS. 7 to 9, the horizontal axis lists, from left to right, N, H100, H50, H0, H-50, and H-100, which represent a model (not shown) of a conventional radiation shielding plate (hereinafter referred to as conventional plate N) without the opening 32. The model of conventional plate N is set in the same way as the model of radiation shielding plate 1, except that the opening 32 is not provided. For H100, H50, H0, H-50, and H-100, data for W100, W50, W0, W-50, and W-100 are listed, from left to right, respectively. At the top of each data bar, a solid error bar is drawn, representing the statistical error (1σ=68%) of the Monte Carlo calculation.

[0043] As shown in Figures 7 to 9, the average relative dose tends to decrease as the change amounts H and W decrease for all of the lens, thyroid, and ovaries. The average relative dose is almost equal to the average relative dose of the conventional plate N for H0 and W0 for all of the lens, thyroid, and ovaries. Therefore, when the openings 32 are L1 = 300 mm and L2 = 200 mm, the radiation shielding plate 1 has almost the same X-ray shielding performance as the conventional plate N, which does not have an opening 32. Therefore, the radiation shielding plate 1 can ensure both workability and X-ray shielding performance when the openings 32 are L1 = 300 mm and L2 = 200 mm.

[0044] FIG. 10 is a graph comparing the exposure distribution of the human body in the first setting for each size of the opening 32. Figure 10 shows the exposure distribution in the model of medical worker B. From top to bottom, Figure 10 shows the exposure distribution of the human body at W100, W0, and W-100. From left to right, Figure 10 shows the exposure distribution of the human body at H100, H0, and H-100. Figure 10 shows nine patterns of exposure distribution for each combination of the change amounts H and W. Each pattern shows a left side view and a front view of the model of medical worker B. Hereinafter, the part of the human body where the relative dose is 0.25 or more when the maximum dose is 1 is referred to as the highly exposed part D. In Figure 10, the highly exposed part D is indicated by hatching on the model of medical worker B.

[0045] 10, in the cases of H0 and W0, no highly exposed portion D occurs. Therefore, the radiation shielding plate 1 can ensure X-ray shielding performance when the opening 32 is L1=300 mm and L2=200 mm. In the case of W100, the highly exposed area D occurs regardless of the amount of change H. In the case of H100, the highly exposed area D occurs only in the case of W100. Therefore, the amount of change W contributes more to the occurrence of the highly exposed area D than the amount of change H. Highly exposed areas D occur only on the left and right side edges of the arms and waist for all combinations of variations H and W. This shows that the dose to the face, neck, and lower abdomen is reduced for all combinations of variations H and W. Therefore, the radiation shielding plate 1 can protect the crystalline lens, thyroid gland, and ovaries from exposure as long as the variations H and W of the opening 32 are within the range of -100 mm to 100 mm.

[0046] Next, the results of the simulation performed with the second setting (L4=107 cm (RAO9 CAU1)) will be explained. FIG. 11 is a graph comparing the average relative dose to the crystalline lens at the second setting for each size of the opening 32. FIG. 12 is a graph comparing the average relative dose to the thyroid gland for each size of the opening 32 in the second setting. FIG. 13 is a graph comparing the average relative dose to the ovaries for each size of the opening 32 in the second setting.

[0047] 11 to 13 show the average relative doses in the lens, thyroid, and ovaries of medical worker B, respectively. In FIGS. 11 to 13, the vertical axis represents the average relative dose, and the horizontal axis represents the change in width L2 of opening 32, W. In FIGS. 11 to 13, the horizontal axis lists N, H100, H50, H0, H-50, and H-100. For H100, H50, H0, H-50, and H-100, data for W100, W50, W0, W-50, and W-100 are listed, from left to right. At the top of each data bar, a solid error bar represents the statistical error (1σ = 68%) of the Monte Carlo calculation. As shown in Figures 11 to 13, the average relative dose tends to decrease as the change amounts H and W decrease for the lens, thyroid, and ovaries. The average relative dose is almost equal to the average relative dose of the conventional plate N for H0 and W0 for the lens, thyroid, and ovaries. Therefore, when the openings 32 are L1 = 300 mm and L2 = 200 mm, the radiation shielding plate 1 has almost the same X-ray shielding performance as the conventional plate N, which does not have openings 32. Therefore, the radiation shielding plate 1 can ensure both workability and X-ray shielding performance when the openings 32 are L1 = 300 mm and L2 = 200 mm.

[0048] FIG. 14 is a graph comparing the exposure distribution of the human body in the second setting for each size of the opening 32. FIG. 14 shows the exposure distribution in the model of medical worker B. From top to bottom, FIG. 14 shows the exposure distribution of the human body at W100, W0, and W-100. From left to right, FIG. 14 shows the exposure distribution of the human body at H100, H0, and H-100. FIG. 14 shows nine patterns of exposure distribution for each combination of the amounts of change H and W. Each pattern shows a left side view and a front view of the model of medical worker B. In FIG. 14, the highly exposed area D is indicated by hatching on the model of medical worker B. 14, in the cases of H0 and W0, the highly exposed portion D does not occur. Therefore, the radiation shielding plate 1 can ensure the X-ray shielding performance when the opening 32 is L1=300 mm and L2=200 mm. In the case of W100, the highly exposed area D occurs regardless of the amount of change H. In the case of H100, the highly exposed area D occurs only in the case of W100. Therefore, the amount of change W contributes more to the occurrence of the highly exposed area D than the amount of change H. Highly exposed areas D occur only on the left and right side edges of the arms and waist for all combinations of variations H and W. This shows that the dose to the face, neck, and lower abdomen is reduced for all combinations of variations H and W. Therefore, the radiation shielding plate 1 can protect the crystalline lens, thyroid gland, and ovaries from exposure as long as the variations H and W of the opening 32 are within the range of -100 mm to 100 mm.

[0049] Comparing the simulations for the first setting and the second setting, both simulations showed similar trends in the X-ray shielding performance of the radiation shielding plate 1. The difference between the first setting and the second setting is the placement of the image receptor 113, i.e., the X-ray irradiation direction. This shows that the radiation shielding plate 1 can ensure both operability and X-ray shielding performance regardless of the placement of the image receptor 113 (X-ray irradiation direction).

[0050] According to the above-described embodiment, the following actions and effects can be obtained. In this embodiment, the first plate portion 10, the second plate portion 20, and the intermediate portion 30 are formed of a radiation-shielding material that blocks radiation. As a result, the radiation-shielding plate can block radiation, and by being placed between the radiation source 111 and medical worker B, the medical worker B's body can be protected from radiation exposure. The second plate portion 20 has a light-transmitting portion 23. This allows the medical worker B to work while viewing the radiation source 111 side of the radiation shielding plate 1 through the light-transmitting portion 23, while positioned on the opposite side of the radiation shielding plate 1 from the radiation source 111. Therefore, the radiation shielding plate 1 can maintain workability. The middle portion 30 has openings 32. A pair of openings 32 are provided outside the narrow portion 31 in the left-right direction. This allows medical worker B to extend only his / her arm toward the radiation source 111 through the openings 32 while positioned on the opposite side of the narrow portion 31 from the radiation source 111. Therefore, medical worker B can perform work closer to the radiation source 111 than the radiation shielding plate 1 while being protected from radiation exposure by the radiation shielding plate 1. Therefore, the radiation shielding plate 1 can protect the human body of medical worker B from radiation exposure while maintaining workability.

[0051] In this embodiment, the radiation-shielding material contains lead. Lead is generally known to provide good radiation shielding. The first plate portion 10, the second plate portion 20, and the intermediate portion 30 can provide good radiation shielding due to lead, so that the medical worker B's body can be effectively protected from radiation exposure.

[0052] In this embodiment, the intermediate section 30 is provided with a door section 34 that can open and close the opening 32. Medical worker B can open and close the opening 32 by operating the door section 34. This allows medical worker B to open the opening 32 when working and extend only his / her arm through the opening 32 toward the radiation source 111. When not working, medical worker B can close the opening 32 to shield himself / herself from radiation. Therefore, when working, medical worker B can perform his / her work while protecting himself / herself from exposure, and can also be well protected from exposure when not working.

[0053] In this embodiment, the door portion 34 is provided so as to be rotatable in the front-rear direction around an axis O along the left-right direction at the left-right end portion of the narrow width portion 31. As a result, the radiation shielding plate 1 can easily open and close the opening 32 by simply rotating the door portion 34 in the front-rear direction around the axis O along the left-right direction.

[0054] In this embodiment, the width L2 of the opening 32 in the left-right direction is 200 mm. The width L2 of the opening 32 in the left-right direction is preferably 200 mm or more and 300 mm or less. This allows the medical worker B to easily extend only his / her arm toward the radiation source 111 through the opening 32, compared to when the width L2 of the opening 32 in the left-right direction is narrower than 200 mm. The radiation shielding plate 1 can better protect the medical worker B from radiation exposure, compared to when the width L2 of the opening 32 in the left-right direction is wider than 300 mm. Therefore, the medical worker B can perform work closer to the radiation source 111 than the radiation shielding plate 1 while being well protected from radiation exposure by the radiation shielding plate 1. Therefore, the radiation shielding plate 1 can maintain workability while well protecting the human body of the medical worker B from radiation exposure. The left-right width of the door section 34 is preferably 200 mm or more and 300 mm or less. It is even more preferable that the left-right width of the door section 34 is 200 mm. In this embodiment, the left-right width of the door section 34 is 200 mm, which is the same as the left-right width L2 of the opening 32. This allows the door section 34 to block the entire left-right area of ​​the opening 32. Medical worker B can be effectively shielded from radiation by blocking the opening 32 when not working. Therefore, medical worker B can be effectively protected from exposure even when not working.

[0055] In this embodiment, the intermediate section 30 is provided rotatable in the front-rear direction around an axis O along the left-right direction, and has a table 33 that can be moved between an installation state P1 in which the main surface faces in the up-down direction and a storage state P2 in which the main surface faces in the front-rear direction. As a result, medical worker B can move the table 33 in the front-rear direction around the axis O along the left-right direction to the installation state P1 in which the main surface faces in the up-down direction. This allows medical worker B to place tools necessary for work on the table 33. Therefore, the radiation shielding plate 1 can maintain workability. The medical worker B can rotate the table 33 in the front-rear direction around the axis O along the left-right direction to place the table 33 in the storage state P2 with the main surface facing in the front-rear direction. This allows the medical worker B to stack the table 33 on the narrow width portion 31 when the table 33 is not in use. Therefore, the radiation shielding plate 1 can prevent the work space from being narrowed by the table 33 when the table 33 is not in use.

[0056] In this embodiment, the vertical middle portion of the opening 32 is located 1050 mm above the floor surface F. As a result, the vertical middle portion of the opening 32 is located in a range of 900 mm to 1200 mm above the floor surface F. It is generally known that the position of an adult's waist is located in a range of 900 mm to 1200 mm above the floor surface F. The radiation shielding plate 1 can provide the vertical middle portion of the opening 32 at the position of an adult's waist. As a result, the medical worker B can extend his / her arm toward the radiation source 111 through the opening 32 without bending over excessively. Therefore, the radiation shielding plate 1 maintains workability.

[0057] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible within the scope of the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the scope of the appended claims.

[0058] In the above embodiment, the radiation emitted from the radiation source 111 is X-rays, but this is not limiting. Therefore, the radiation shielding plate 1 may be used to shield radiation other than X-rays. The radiation shielding plate 1 may be used in medical facilities other than those for catheter surgery using the radiation device 110. The radiation shielding plate 1 may be used in facilities that handle radiation other than medical facilities. In the above embodiment, the radiation-shielding materials forming the first plate portion 10, the second plate portion 20, and the intermediate portion 30 each contain lead, but they do not have to have lead as their main component. The radiation-shielding materials forming the first plate portion 10, the second plate portion 20, and the intermediate portion 30 do not have to contain lead and may be resin, as long as they can shield radiation.

[0059] In the above embodiment, a pair of openings 32 are provided on the outer side of the narrow width portion 31 in the left-right direction, but it is sufficient that the openings 32 are provided on at least one side of the narrow width portion 31 in the left-right direction. In the above embodiment, the door portion 34 is configured to be rotatable in the front-rear direction around the axis O along the left-right direction by the second hinge 36, but this is not limited to this. The door portion 34 may be provided so as to be slidable in the left-right direction relative to the first plate portion 10 and the second plate portion 20, for example. In this case, the door portion 34 may be provided so as to overlap the narrow portion 31 or be housed inside the narrow portion 31 when the opening portion 32 is opened. The door portion 34 may be provided so as to be removable from the opening portion 32.

[0060] A radiation shielding plate 201 according to the second embodiment of the present invention will be described below. In the second embodiment, the same configurations as those in the first embodiment described above are given the same names and reference numerals, and the description thereof will be omitted as appropriate.

[0061] (Radiation shielding plate) FIG. 15 is a rear view of the radiation shielding plate 201. As shown in FIG. As shown in FIG. 15, the radiation shielding plate 201 includes a shielding plate main body 201a supported by a pair of legs 211 spaced apart from each other in the left-right direction, and an accessory plate 240 removably provided on the shielding plate main body 201a.

[0062] The shielding plate main body 201a is a flat plate-like member extending in the up-down and left-right directions. The shielding plate main body 201a is generally formed in a rectangular shape with short sides in the left-right direction when viewed in the front-to-back direction. The height of the shielding plate main body 201a in the up-down direction is, for example, 1900 mm. The width of the shielding plate main body 201a in the left-right direction is, for example, 950 mm. The shielding plate main body 201a is formed from a lead acrylic plate. Therefore, the entire shielding plate main body 201a is a light-transmitting transmission portion 223. The shielding plate main body 201a includes a first plate portion 210, a second plate portion 220, and an intermediate portion 230.

[0063] (1st plate part) The first plate portion 210 is supported by legs 211 and is installed in a state where it is floating above the floor surface F. When viewed from the front-to-rear direction, the first plate portion 210 is formed in a rectangular shape having long sides extending in the left-to-right direction.

[0064] (Second board part) The second plate portion 220 is provided above the first plate portion 210. When viewed from the front-rear direction, the second plate portion 220 is formed in a rectangular shape having long sides extending in the left-right direction.

[0065] (middle part) The middle portion 230 has a narrow portion 231 , a first connecting portion 233 , a second connecting portion 234 , and an opening 232 .

[0066] (Narrow part) The narrow width portion 231 is provided between the first plate portion 210 and the second plate portion 220. When viewed from the front-rear direction, the narrow width portion 231 is formed in a rectangular shape with short sides in the left-right direction. When viewed from the front-rear direction, the narrow width portion 231 is located in the central region of the shielding plate main body 201a.

[0067] The first connecting portion 233 is provided between the first plate portion 210 and the narrow width portion 231. The first connecting portion 233 is a flat plate that is rectangular when viewed in the front-to-rear direction, and connects the first plate portion 210 and the narrow width portion 231. The first connecting portion 233 extends from the right edge of the narrow width portion 231 to the left edge of the first plate portion 210. The second connecting portion 234 is provided between the second plate portion 220 and the narrow width portion 231. The second connecting portion 234 is a flat plate that is rectangular when viewed in the front-to-rear direction, and connects the second plate portion 220 and the narrow width portion 231. The second connecting portion 234 extends from the left edge of the narrow width portion 231 to the right edge of the second plate portion 220. The above-described first plate portion 210, second plate portion 220, narrow width portion 231, first connecting portion 233, and second connecting portion 234 are integrally formed.

[0068] (Opening) A pair of openings 232 are provided in the left-right direction with a narrow width portion 231 sandwiched between them. Each opening 232 is formed in a U-shape when viewed in the front-to-rear direction, opening in the front-to-rear direction and on the side opposite the narrow width portion 231. The pair of openings 232 are formed asymmetrically. Hereinafter, the left opening 232 of the pair of openings 232 will be referred to as a first opening 232a, and the right opening 232 will be referred to as a second opening 232b.

[0069] The first opening 232a is formed by being surrounded by the edges of the second plate portion 220, the second connecting portion 234, the narrow portion 231, and the first connecting portion 233. The first opening 232a is designed with dimensions suitable for the procedure of the ultrasound surgeon B2. Specifically, the first opening 232a is formed at a position spaced, for example, 1000 mm above the lower edge of the first plate portion 210. The vertical and horizontal dimensions of the first opening 232a are both, for example, 400 mm. The second opening 232b is formed by being surrounded by the edges of the first plate portion 210, the first connecting portion 233, the narrow portion 231, and the second connecting portion 234. The second opening 232b is designed with dimensions suitable for the procedure of anesthesiologist B1. Specifically, the second opening 232b is formed at a position spaced apart, for example, 900 mm above the lower edge of the first plate portion 210. The vertical dimension of the second opening 232b is, for example, 400 mm, and the horizontal dimension of the second opening 232b is, for example, 350 mm.

[0070] (Attached plate) An accessory plate 240 is fitted into each opening 232. That is, a pair of accessory plates 240 are installed with the narrow width portion 231 sandwiched between them. When viewed from the front-to-rear direction, each accessory plate 240 is formed in a U-shape that opens on the opposite side of the narrow width portion 231 in the left-to-right direction. When viewed from the front-to-rear direction, the outer shape of the accessory plate 240 is formed to have the same shape and dimensions as the corresponding opening 232. Like the shielding plate main body 201a, the accessory plate 240 is made of a lead acrylic plate. Therefore, the accessory plate 240 is light-transmitting.

[0071] When the accessory plate 240 is fitted into the opening 232, the main surface 240c faces in the front-to-rear direction. Since the plate thickness of the accessory plate 240 is equal to the plate thickness of the shielding plate main body 201a, when the accessory plate 240 is fitted into the opening 232, the main surface 240c of the accessory plate 240 is flush with the main surface 201b of the shielding plate main body 201a. In other words, the main surface 240c of the accessory plate 240 is flush with the main surface 210a of the first plate portion 210 and the main surface 220a of the second plate portion 220.

[0072] The attachment plate 240 is also removable from the opening 232 .

[0073] The pair of accessory plates 240 are formed asymmetrically. Each accessory plate 240 has a small opening 241 that opens in the front-rear direction.

[0074] The small openings 241 are provided so that medical worker B, who is positioned on the opposite side of the radiation shielding plate 201 from the radiation source 111, can reach out and work toward the radiation source 111 through the small openings 241. Each small opening 241 also opens on the opposite side of the narrow portion 231 in the left-right direction. When viewed from the front-to-back direction, the small openings 241 are formed in a U-shape that opens on the opposite side of the narrow portion 231 in the left-right direction. The small openings 241 are smaller than the corresponding openings 232.

[0075] Hereinafter, of the pair of attachment plates 240, the attachment plate 240 fitted into the first opening 232a will be referred to as the first attachment plate 240a, and the attachment plate 240 fitted into the second opening 232b will be referred to as the second attachment plate 240b. Furthermore, the small dimension opening 241 of the first attachment plate 240a will be referred to as the first small dimension opening 241a, and the small dimension opening 241 of the second attachment plate 240b will be referred to as the second small dimension opening 241b.

[0076] Like the first opening 232a, the first attachment plate 240a is designed with dimensions suitable for the procedure of the ultrasound surgeon B2. Specifically, the vertical and horizontal dimensions of the first attachment plate 240a are both, for example, 400 mm. The first small opening 241a is formed at a position, for example, 50 mm above the lower edge of the first attachment plate 240a. The vertical dimension of the first small opening 241a is, for example, 200 mm, and the horizontal dimension of the first small opening 241a is, for example, 350 mm.

[0077] Like the second opening 232b, the second attachment plate 240b is designed with dimensions suitable for the procedure of anesthesiologist B1. Specifically, the vertical dimension of the second attachment plate 240b is, for example, 400 mm, and the horizontal dimension of the second attachment plate 240b is, for example, 350 mm. The second small opening 241b is formed at a position spaced, for example, 50 mm above the lower edge of the second attachment plate 240b. The vertical dimension of the second small opening 241b is, for example, 200 mm, and the horizontal dimension of the second small opening 241b is, for example, 300 mm.

[0078] (Simulation of radiation shielding) A simulation of the radiation shielding plate 201 will be described below. This simulation was carried out to confirm the shielding performance of the radiation shielding plate 201. Among the conditions of this simulation, the description of the conditions common to the first embodiment will be omitted as appropriate.

[0079] FIG. 16 is a perspective view showing a simulation model for confirming the radiation shielding performance of the radiation shielding plate. 16 shows a simple flat plate-like model of the radiation shielding plate 201 with the accessory plate 240 removed. The model of the radiation shielding plate 201 is set as a plate made of lead and 1 mm thick in the front-to-back direction. Furthermore, two models of medical staff B are placed behind the model of the radiation shielding plate 201 (on the opposite side of the radiation shielding plate 201 from the patient A). Of the two models of medical staff B, the model on the left facing the first opening 232a is a model of the ultrasound surgeon B2, and the model on the right facing the second opening 232b is a model of the anesthesiologist B1.

[0080] FIG. 17 is a top view of the model of the medical system of FIG. 17, the models of ultrasound surgeon B2 and anesthesiologist B1 are positioned so that they are rotated 45 degrees outward and 45 degrees inward to the left, respectively, with respect to patient A. In other words, the model of ultrasound surgeon B2 and the model of anesthesiologist B1 are positioned so that they face the same direction.

[0081] A simulation was performed using the above-described model by Monte Carlo calculation. This simulation was performed under the following conditions: no radiation shielding plate was placed between patient A and medical worker B (Case 0); a conventional radiation shielding plate without openings 232 (Normal); a radiation shielding plate 201 with openings 232 was used without the accessory plates 240 attached (Case 1); and a radiation shielding plate 201 with openings 232 was used with the accessory plates 240 attached to both openings 232 (Case 2). Note that the dimensions of the model of the radiation shielding plate 201 were set to values ​​equal to the dimensions of the second embodiment described above.

[0082] As in the first embodiment, the parameters of this simulation have the values ​​shown in Table 1. Furthermore, as in the first embodiment, the distance L4 from the radiation source 111 to the image receptor 113 and the fluoroscopy direction of the radiation were set, and simulations were performed for the first setting (L4 = 98 cm (LAO16 CRA13)) and the second setting (L4 = 107 cm (RAO9 CAU1)). When the fluoroscopy direction setting is changed, the radiation point of the radiation source 111 moves to a position symmetrical to the image receptor 113, and therefore the absorbed dose differs between the first setting and the second setting even if other conditions are the same.

[0083] (Absorbed dose to organs at risk) Using this simulation, we calculated the dose absorbed by the eye lens, thyroid, and ovaries of medical worker B. Specifically, the absorbed dose in Case 0 was set to 1, and the relative absorbed dose when a radiation shield was used was calculated. The relative absorbed dose is independent for each fluoroscopy direction and organ. Calculations of the relative absorbed dose for each organ were performed for ultrasound surgeon B2 and anesthesiologist B1, respectively.

[0084] First, we will describe the calculation results of ultrasound doctor B2. Figures 18, 19, and 20 are graphs showing the relative absorbed doses of the eye lens, thyroid gland, and ovaries of ultrasound surgeon B2, respectively. In Figures 18, 19, and 20, the horizontal axis represents the conditions related to the radiation shielding plate, and the vertical axis represents the relative absorbed dose. In Figures 18, 19, and 20, the open circles represent values ​​obtained with the second setting (RAO9 CAU1), and the open squares represent values ​​obtained with the first setting (LAO16 CRA13). In Figures 18, 19, and 20, the error bars represent the statistical error (1σ) of the Monte Carlo calculation.

[0085] As shown in Figures 18 to 20, it was confirmed that in all organs, regardless of whether the setting was 1 or 2, the absorbed dose in Case 1 was significantly higher than that in Normal, whereas the absorbed dose in Case 2 was close to that in Normal. In particular, in the crystalline lens, the reduction in absorbed dose in Case 2 compared to Case 1 was remarkable.

[0086] Next, the calculation results of anesthesiologist B1 will be described. Figures 21, 22, and 23 are graphs showing the relative absorbed doses for the eye lens, thyroid gland, and ovaries of anesthesiologist B1, respectively. In Figures 21, 22, and 23, the horizontal axis represents the conditions related to the radiation shielding plate, and the vertical axis represents the relative absorbed dose. In Figures 21, 22, and 23, the open circles represent values ​​for the second setting (RAO9 CAU1), and the open squares represent values ​​for the first setting (LAO16 CRA13). In Figures 21, 22, and 23, the error bars represent the statistical error (1σ) of the Monte Carlo calculation.

[0087] As shown in Figures 21 to 23, it was confirmed that for all organs, regardless of whether the setting was 1 or 2, Case 1 significantly increased the absorbed dose compared to Normal, whereas Case 2 had an absorbed dose close to Normal. In particular, for the thyroid and ovaries, the reduction in absorbed dose for Case 2 compared to Case 1 was remarkable.

[0088] In this way, it was confirmed that by fitting the accessory plate 240 into the opening 232 (Case 2), the absorbed dose in each organ became close to the absorbed dose when a conventional radiation shielding plate without the opening 232 was used (Normal). The ultrasound surgeon B2, positioned on the first opening 232a side, was able to confirm the same shielding performance as Normal for radiation irradiated to the crystalline lens. The anesthesiologist B1, positioned on the second opening 232b side, was able to confirm the same shielding performance as Normal for radiation irradiated to the thyroid and ovaries.

[0089] (Absorbed dose distribution in the skin) This simulation was used to calculate the absorbed dose distribution in the skin of medical worker B. Specifically, the maximum absorbed dose in the skin in Case 0 was set to 1, and the relative absorbed dose when using the radiation shielding plate 201 was calculated at each position on the skin to create a relative absorbed dose distribution. Calculations of the relative absorbed dose distribution in the skin were performed for ultrasound surgeon B2 and anesthesiologist B1, respectively.

[0090] First, we will describe the calculation results of ultrasound doctor B2. Figure 24 is a graph showing the relative skin absorbed dose distribution of ultrasound surgeon B2. In Figure 24, the horizontal axis represents the conditions related to the radiation shielding plate, and the vertical axis represents the fluoroscopy direction setting (either the first setting (LAO16 CRA13) or the second setting (RAO9 CAU1)). Figure 24 shows a total of six patterns of relative skin absorbed dose distribution. For each pattern, a left oblique view (Left) and a front oblique view (Front) of the model of ultrasound surgeon B2 are shown. In addition, in Figure 24, areas where the relative dose is 0.25 or more are displayed as highly exposed areas D.

[0091] As shown in Figure 24, in both the first and second settings, in Case 2, high exposure area D occurred, but it was confirmed that high exposure area D was reduced compared to Case 1.

[0092] Next, the calculation results of anesthesiologist B1 will be described. Figure 25 is a graph showing the relative skin absorption dose distribution of anesthesiologist B1. In Figure 25, the horizontal axis represents the conditions related to the radiation shielding plate, and the vertical axis represents the fluoroscopy direction setting (either the first setting (LAO16 CRA13) or the second setting (RAO9 CAU1)). Figure 25 shows a total of six patterns of skin absorption line distribution. For each pattern, a left oblique view (Left) and a front oblique view (Front) of the model of anesthesiologist B1 are shown. In addition, in Figure 25, areas where the relative dose is 0.25 or more are displayed as highly exposed areas D.

[0093] As shown in Figure 25, in both the first and second settings, in Case 2, high exposure area D occurred, but it was confirmed that high exposure area D was reduced compared to Case 1.

[0094] As described above, it was confirmed that the high exposure area D is significantly reduced when the opening 232 is closed by the accessory plate 240 (Case 2) compared to when the entire opening 232 is open (Case 1). This result means that the accessory plate 240 has radiation shielding properties.

[0095] In this embodiment, the radiation shielding plate 201 is fitted into the opening 232 with the main surface 240c facing the front-rear direction, and includes an attachment plate 240 that is detachable from the opening 232.

[0096] This allows, for example, when no radiation is being emitted, the arm to be passed through the opening 232 with the accessory plate 240 removed. Therefore, it becomes easy to work on the radiation source 111 side while being on the opposite side of the radiation shielding plate 201 from the radiation source 111. In other words, workability can be improved.

[0097] In this embodiment, the accessory plate 240 has a small opening 241 that opens in the front-to-rear direction. As a result, for example, when the radiation dose is high, the size of the opening 232 can be adjusted by fitting the accessory plate 240 into the opening 232. Because the size of the small opening 241 is smaller than the size of the opening 232, fitting the accessory plate 240 can improve the radiation shielding performance. Furthermore, medical worker B can work on the radiation source 111 side by putting his / her arm through the small opening 241. In other words, it is possible to maintain workability while improving the radiation shielding performance.

[0098] In addition, because accessory plate 240 has a simple structure that only has small-sized opening 241, it is easier to adjust the size of opening 232 compared to opening and closing opening 232 with a curtain or sliding door. Furthermore, because accessory plate 240 does not have any unnecessary structure, it is possible to prevent dust from getting stuck in gaps and prevent hands from touching unnecessary places during work, thereby maintaining cleanliness in the operating room.

[0099] In this embodiment, a pair of openings 232 are provided in the left and right direction across the narrow width portion 231. The pair of openings 232 are formed asymmetrically. This allows, for example, when two medical workers B work side by side in front of the radiation shielding plate 201, to select the opening 232 that is appropriate for each of their tasks.

[0100] For example, an ultrasound surgeon B2 is positioned in front of the first opening 232a, and an anesthesiologist B1 is positioned at the second opening 232b. In this embodiment, of the two openings 232, the first opening 232a is positioned higher than the second opening 232b and is larger than the second opening 232b. This allows the ultrasound surgeon B2 and the anesthesiologist B1 to select the opening 232 that is appropriate for their respective procedures and work therein. This further improves workability.

[0101] In the above embodiment, the entire shielding plate body 201a is the light-transmitting portion 223, but this is not limited to this. Only the second plate portion 220 of the shielding plate body 201a may be the light-transmitting portion 223.

[0102] Furthermore, in the above embodiment, the accessory plate 240 has the small opening 241, but this is not limited to this. The accessory plate 240 may be formed in a rectangular shape when viewed in the front-to-rear direction, without the small opening 241. By using such an accessory plate 240 without the small opening 241, it is possible to achieve a shape similar to that of a conventional shielding plate without an opening.

[0103] In addition, within the scope of the spirit of the present invention, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described modified examples may be combined as appropriate. [Industrial Applicability]

[0104] The present invention relates to a radiation shielding plate, which can protect the human body from radiation exposure while maintaining workability. [Explanation of symbols]

[0105] 1...radiation shielding plate, 10...first plate portion, 10a...main surface, 20...second plate portion, 20a...main surface, 23...transmitting portion, 30...middle portion, 31...narrow portion, 32...opening, 33...table, 34...door portion, 201...radiation shielding plate, 210...first plate portion, 210a...main surface, 220...second plate portion, 220a...main surface, 223...transmitting portion, 230...middle portion, 231...narrow portion, 232...opening, 240...accessory plate, 240c...main surface, 241...small opening, F...floor surface, L2...width, O...axis, P1...installed state, P2...storage state

Claims

1. a first plate portion formed of a radiation shielding material that blocks radiation and placed on a floor surface with a main surface facing in the front-rear direction; a second plate portion formed of a radiation-shielding material that blocks radiation, disposed above the first plate portion with a main surface facing in the front-rear direction, and having a light-transmitting portion; an intermediate portion formed of a radiation-shielding material that blocks radiation, the intermediate portion being provided between the first plate portion and the second plate portion, the intermediate portion having a narrow portion whose width in the left-right direction is narrower than the widths of the first plate portion and the second plate portion in the left-right direction, and an opening portion that is provided at least on one side of the narrow portion in the left-right direction and opens in the front-rear direction; Equipped with The width of the opening in the left-right direction is 200 mm or more and 300 mm or less. Radiation shielding plate.

2. The radiation shielding plate according to claim 1 , wherein the radiation shielding material comprises lead.

3. The radiation shielding plate according to claim 1 or 2, wherein the intermediate portion is provided with a door portion that can open and close the opening portion.

4. The radiation shielding plate according to claim 3 , wherein the door portion is provided at the left and right ends of the narrow width portion so as to be rotatable in the front-rear direction around an axis extending in the left-right direction.

5. A radiation shielding plate as described in claim 3 or claim 4, wherein the width of the door portion in the left-right direction is 200 mm or more and 300 mm or less.

6. The radiation shielding plate according to claim 1 or 2, further comprising an accessory plate that is fitted into the opening with its main surface facing the front-rear direction and is detachable from the opening.

7. The radiation shielding plate according to claim 6, wherein the accessory plate has a small opening opening in the front-rear direction.

8. 8. The radiation shielding plate according to claim 1, wherein the intermediate portion has a table that is rotatable in the front-rear direction around an axis along the left-right direction and that can be moved between an installation state in which a main surface faces in the up-down direction and a storage state in which the main surface faces in the front-rear direction.

9. The radiation shielding plate according to any one of claims 1 to 8, wherein a vertically intermediate portion of the opening is provided in a range of 900 mm to 1200 mm above the floor surface.

10. The openings are provided in pairs in the left and right directions with the narrow portion between them, The radiation shielding plate according to claim 1 , wherein the pair of openings are formed asymmetrically.

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