JP5227160B2 - Radiation shielding structure - Google Patents

Description

  The present invention relates to a radiation shielding structure for a radiation projection surface in a radiation utilization facility.

In an irradiation room of a radiation utilization facility, a shielding member such as a steel material is embedded in an irradiation surface of a wall or a ceiling in order to shield radiation irradiated on a radiation projection surface from a radiation source (for example, Patent Document 1). reference).
JP-A-2-173600

  As shown in FIG. 6, in the conventional shielding structure 51, a highly shielding member made of a metal such as steel or lead (hereinafter referred to as “shielding member 52”) is provided on the indoor side or inside of the reinforced concrete structure 54 serving as a building frame. In order to support the shielding member 52, it is necessary to separately provide a reinforced concrete structure 53 on the indoor side surface of the shielding member 52. In such a shielding structure 51, an extra reinforced concrete structure 53 for supporting the shielding member 52 described above is required in addition to the building structure, which is uneconomical.

  Therefore, the present invention has been devised to solve the above problems, and an object thereof is to provide a radiation shielding structure that can achieve cost reduction required for constructing the shielding structure.

In order to solve the above-described problems, the present invention provides a radiation shielding structure for an irradiation chamber that accommodates a high-energy linac serving as a radiation source. The high-energy linac includes a rotatable gantry section and a full angle toward its rotation center. The radiation shielding structure includes a portal-type reinforced concrete structural frame formed by integrally forming a wall structural frame and a ceiling structural frame, and the wall structure. A wall shielding member for shielding radiation is erected on the walls located in the radiation direction on both sides of the high energy linac on the indoor side of the housing, and the wall shielding member is placed on the wall from the irradiation unit. It is formed in a horizontal length that can cover the tip of the radiation irradiated sideways toward the side, and the lower end of the wall shielding member is positioned below the floor surface, End is positioned in the ceiling surface substantially equal in height, the upper end portion of said wall shield member, the protruding portion protruding interior side is formed over the entire length of the horizontal longitudinal direction of the wall shielding member, said ceiling On the structural housing, a ceiling shielding member that shields radiation is separated from the wall shielding member, and is laid so as to cover an upper portion of a space between the wall shielding members facing each other , and the ceiling shielding member has a rectangular shape. One side is the same length as the horizontal length of the wall shielding member, and the wall shielding member and the ceiling shielding member are an iron plate, a lead plate, a polyethylene plate, or a boron-containing material plate. is configured in either the protrusion radiation said ceiling shielding member which is linearly emitted from the high energy linac to be the radiation source, impinging on one of said wall shield member or the protruding part As shielded, in cross section in the vertical direction, the extension line of the straight line is formed so as to intersect the roof shielding member connecting said irradiation portion and the upper portion of the indoor-side tip portion of the protruding portion This is a radiation shielding structure.

Thus, if the wall shielding member and the ceiling shielding member are separated and the ceiling shielding member is placed on the ceiling structure housing, the ceiling shielding member can be supported by the ceiling structure housing. No extra reinforced concrete structures are required. Therefore, the material and construction cost required for the construction of the shielding structure can be reduced. Moreover, since the wall structure casing and the ceiling structure casing are structurally integrated, they can be applied at the same time, so that the construction labor can be reduced and the workability can be improved. Further, by forming the projecting portion so that the straight extension line connecting the tip portion of the projecting portion and the irradiation portion intersects the ceiling shielding member, the radiation radiated linearly from the irradiation portion is the ceiling shielding member, come to be shielded by any of the wall shielding member or protrusion, even if the distance between the ceiling shield member and the wall shielding member is large, it is possible to reliably shield radiation.

Further, the present invention provides a radiation shielding structure for an irradiation chamber that accommodates a high energy linac serving as a radiation source. The high energy linac can irradiate radiation from all angles toward a rotatable gantry section and its rotation center. The radiation shielding structure includes a portal-type reinforced concrete structural frame formed by structurally integrally forming a wall structural frame and a ceiling structural frame, and is provided on the indoor side of the wall structural frame. A wall shielding member that shields radiation is erected on the walls positioned in the radiation irradiation direction on both sides of the high energy linac, and the wall shielding member irradiates laterally from the irradiation unit toward the wall. The lower end of the wall shielding member is positioned below the floor surface, and the upper end is substantially the same as the ceiling surface. Is the position of the height, on the ceiling structural framework is ceiling shielding member for shielding radiation is separated from the wall shielding member, is laid so as to cover the upper part of the space between the wall shielding member facing each other, The ceiling shielding member has a rectangular shape, one side of which is the same length as the horizontal length of the wall shielding member, and the end of the ceiling shielding member on the wall structure housing side has the wall An extending portion extending outward from the outer surface of the shielding member is formed, and the wall shielding member and the ceiling shielding member are any of an iron plate, a lead plate, a polyethylene plate, or a boron-containing material plate. is constituted by one, the extending portion is shielded radiation is linearly emitted from the high energy linac serving as the radiation source is the ceiling shielding member, when any one of said wall shield member or the extending portion As, in cross section in the vertical direction, crossing the extension line of the line connecting the indoor side of the upper portion of the wall shielding member on the side where the extended portion is positioned between the said irradiation portion in the extending portion it is formed so as to be radiation-shielding structure according to claim.

Thus, if the wall shielding member and the ceiling shielding member are separated and the ceiling shielding member is placed on the ceiling structure housing, the ceiling shielding member can be supported by the ceiling structure housing. No extra reinforced concrete structures are required. Therefore, the material and construction cost required for the construction of the shielding structure can be reduced. Moreover, since the wall structure casing and the ceiling structure casing are structurally integrated, they can be applied at the same time, so that the construction labor can be reduced and the workability can be improved. In addition, since the extended portion is formed so that the straight extension line connecting the upper end portion of the wall shielding member and the irradiated portion intersects the extended portion , the radiation radiated linearly from the irradiated portion is shielded from the ceiling. member, will be shielded by any of the wall shielding member or the extending portion, even if the distance between the ceiling shield member and the wall shielding member is large, it is possible to reliably shield radiation.

  In the present invention, it is preferable that the wall shielding member further includes a wall radiation antireflection layer that is made of concrete and prevents reflection of radiation. According to such a configuration, since the wall shielding member is not exposed, reflection of radiation can be prevented. Further, even when the wall radiation antireflection layer is formed of concrete, it is not necessary to use a structure, so that an increase in the amount of reinforcement can be suppressed.

  Furthermore, it is preferable that the present invention further includes a ceiling reinforced concrete layer formed on the upper side of the ceiling shielding member. The concrete layer added to the ceiling is formed when there is a general room on the upper floor or when there is a rooftop facility. According to such a configuration, since the ceiling shielding member is not exposed, radiation scattering can be reduced. Moreover, since it is not necessary to make the ceiling-reinforced concrete into a structure, an increase in the amount of reinforcement can be suppressed.

  According to the present invention, since an extra reinforced concrete structure for supporting the shielding member can be eliminated, an excellent effect of reducing the material and construction cost required for constructing the shielding structure is exhibited.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the present embodiment, the configuration of the radiation shielding structure 1 formed in the irradiation chamber 2 that houses a high energy linac (radiotherapy device) 3 as a radiation source will be described as an example.

  As shown in FIGS. 1 to 3, the high energy linac 3 includes a radiation generating device 4 and a treatment table 5, and the radiation generating device 4 includes a rotatable gantry unit 4 a. Radiation is irradiated from the irradiation part P provided in 4a toward the affected part of the patient. The irradiation part P is provided so as to face the rotation center G of the gantry part 4a. The irradiation part P can be rotated 360 degrees on the movement locus L around the rotation center G as the gantry part 4a rotates. Thereby, the irradiation part P can irradiate the radiation from all angles toward the rotation center G.

  A radiation shielding structure 1 according to the present invention is a structure that divides the inside and outside of an irradiation chamber that houses a high-energy linac 3 that is a radiation source, and is erected on the indoor side of a reinforced concrete wall structure housing 10 to shield radiation. And a ceiling shielding member 40 that is laid on a reinforced concrete ceiling structure housing 30 that is structurally integrally formed on an upper portion of the wall structure housing 10 and shields radiation. To do. That is, a gate-shaped structure part integrally formed by the wall structure case 10 and the ceiling structure case 30 is formed, the wall shielding member 20 is provided on the inner side, and the ceiling shielding member 40 is provided on the wall shielding member 20. It is the structure provided separately. Further, a wall radiation reflection preventing layer 50 is formed on the indoor side of the wall shielding member 20, and a concrete layer 60 is formed on the ceiling above the ceiling shielding member 40 by increasing the ceiling.

  As shown in FIG. 1, the wall structure frame 10 is formed by placing the horizontal wall bars 11 and the vertical wall bars 12 at a predetermined pitch, and concrete 13 is placed at a predetermined thickness so as to cover them. Yes. The lower end of the vertical wall 12 is inserted into the underground beam 70 (the lower beam when the irradiation chamber 2 is on the second floor or higher), and the upper end is inserted into the upper beam 71. Although not shown, the underground beam 70 and the beam 71 are provided with reinforcing bars such as upper end bars, lower end bars and hoop bars. The thickness of the wall structure 10 is appropriately set according to the intensity of radiation irradiated from the radiation source and the thickness and material of the wall shielding member 20. The concrete thickness determined from the radiation shielding performance is sufficiently thicker than the concrete thickness determined from structural requirements. The wall structure housing 10 is arranged on the outdoor side when viewed in the thickness direction of the wall, and the wall shielding member 20 is arranged on the indoor side.

  As shown in FIGS. 1 and 2, the wall shielding member 20 is disposed on a wall (radiation projection plane) positioned in the radiation irradiation direction on both sides of the high energy linac 3. The wall shielding member 20 is formed in a horizontal length that can cover the front end of the irradiation direction of the radiation irradiated laterally from the irradiation part P of the high energy linac 3 toward the wall. The wall shielding member 20 is configured by laminating iron plates with a predetermined thickness, but the material and shape are not limited thereto. For example, depending on the type of radiation, a lead plate effective for gamma ray shielding, a polyethylene plate effective for neutron shielding, or a boron-containing material plate may be used. If a material having high shielding properties is used, the wall shielding member 20 can be formed thin. The thickness of the wall shielding member 20 is appropriately set according to the intensity of radiation irradiated from the radiation source and the material of the wall shielding member 20.

  The wall shielding member 20 is fixed to the floor structure housing 10 of the building, the wall structure housing 10 and the ceiling structure housing 30 with an anchor as needed, or the lower part is dropped into the floor structure housing to prevent the fall. Also good. Moreover, you may finish the wall shielding member 20 integrally with the wall shielding member 20 by being embed | buried in concrete.

  As shown in FIG. 1, the wall shielding member 20 has a lower end located below the floor surface and an upper end located at substantially the same height as the ceiling surface. At the upper end portion of the wall shielding member 20, a protruding portion 21 that protrudes toward the indoor side of the irradiation chamber 2 is formed. The protrusion 21 is formed over the entire length of the wall shielding member 20 in the length direction (the front and back direction in FIG. 1). The protruding portion 21 is configured by stacking iron plates having a predetermined thickness, and is joined to the upper end of a flat iron plate. In addition, the material of the protrusion part 21 is not limited to steel, For example, according to the kind of radiation, the lead effective in gamma ray shielding, the polyethylene made effective in neutron shielding, or the boron containing material etc. May be used. Further, the protruding portion 21 may be formed integrally with the flat wall shielding member 20. The protruding portion 21 has a protruding dimension such that a linear extension line (indicated by a one-dot chain line in FIG. 1) connecting the upper end of the indoor-side tip and the irradiation portion P intersects a ceiling shielding member 40 described later. Is set. Thereby, the radiation irradiated from the irradiation part P in the wall direction or the ceiling direction always hits any one of the wall shielding member 20, the projecting part 21, and the ceiling shielding member 40 and is reliably shielded. In particular, also in the gap portion between the wall shielding member 20 and the ceiling shielding member 40, the radiation does not leak to the outside by hitting the ceiling shielding member 40 as shown by a one-dot chain line in FIG.

  As shown in FIG. 1, the ceiling structural body 30 has upper end bars 31 and lower end bars 32 arranged in a grid pattern at a predetermined pitch, and concrete 33 is placed with a predetermined thickness so as to cover them. Is formed. The upper end 31 and the lower end 32 are inserted into the upper beam 71 at their ends. The thickness of the ceiling structural body 30 is appropriately set according to the intensity of radiation irradiated from the radiation source and the thickness and material of the ceiling shielding member 40. The ceiling structural body 30 is structurally integrally formed on the upper part of the wall structural body 10 and is formed by placing concrete after the construction of the wall structural body 10. The ceiling structural housing 30 is formed so as to cover the upper end of the wall shielding member 20.

  With such a configuration, the wall structure housing 10 and the ceiling structure housing 30 are integrated to form a cross-sectional gate shape, and a pair of wall shielding members 20 are disposed inside the wall structure member 20 so as to face each other at a predetermined interval. The Rukoto.

  The ceiling shielding member 40 is laid on the ceiling structure housing 30 so as to cover the upper part of the space between the wall shielding members 20 and 20 facing each other, and is spaced from the wall shielding member 20 by a predetermined interval. It is arranged above. The ceiling shielding member 40 is disposed so as to cover the radiation projection surface of the ceiling. The ceiling shielding member 40 is fixed to the ceiling structure housing 30 with an anchor (not shown). The ceiling shielding member 40 may be dropped into the ceiling structure housing 30 and fixed to the ceiling structure housing 30. The ceiling shielding member 30 may be finished by being embedded in concrete.

  The ceiling shielding member 40 has a rectangular shape with a predetermined thickness, and is configured by stacking iron plates to a predetermined thickness. The material and shape of the ceiling shielding member 40 are not limited to this. For example, lead effective for gamma ray shielding, polyethylene made of neutron shielding, or a boron-containing material may be used depending on the type of radiation. The thickness of the ceiling shielding member 40 is appropriately set according to the intensity of radiation irradiated from the radiation source and the material of the ceiling shielding member 40. The ceiling shielding member 40 has a short side portion that is the same length as the horizontal length of the wall shielding member 20, and has a size in which the short side portion overlaps the outer surface of the lower wall shielding member 20 in plan view. . Further, the ceiling shielding member 40 has a long side portion shorter than the separation distance between the adjacent beams 71 and 71, and can be disposed between the beams 71 and 71. In addition, if the protrusion dimension of the protrusion part 21 of the wall shielding member 20 is lengthened, the length of the long side part of the ceiling shielding member 40 can be shortened.

  The wall radiation reflection preventing layer 50 is formed of concrete on the indoor side of the wall shielding member 20. The wall radiation reflection preventing layer 50 is provided to prevent radiation from being reflected indoors by the wall shielding member 20. The wall radiation reflection preventing layer 50 is made of reinforced concrete formed by blasting concrete with a thickness of about 100 mm to 1000 mm. The wall radiation reflection preventing layer 50 is provided with a reinforcing bar or a mesh sheet (not shown) for preventing cracking and peeling of concrete. Since the reinforcing bars for preventing peeling are not arranged for the structure, the amount of arrangement is small. The wall radiation antireflection layer 50 may be installed at the same time as the wall structure 10 or may be post-installed after the construction of the wall structure 10.

  The wall radiation reflection preventing layer 50 may be made of low activation concrete instead of normal concrete. Use of low activation concrete is preferable because it can reduce the activation of the concrete that occurs when the concrete is exposed to neutron radiation. When low activation concrete is employed, the wall radiation antireflection layer 50 is post-installed after the construction of the wall structure 10.

  The ceiling reinforced concrete layer 60 is provided to prevent the upper surface of the ceiling shielding member 40 from being exposed. The ceiling-reinforced concrete layer 60 is formed particularly when there is a general room on the upper floor. The ceiling reinforced concrete layer 60 is formed by blasting concrete with a thickness of about 100 mm to 1000 mm. Reinforced concrete layer 60 is provided with reinforcing bars or mesh sheets (not shown) for preventing cracking and peeling of concrete. In addition, since the reinforcing bars for preventing peeling are not used for structures, the amount of reinforcing bars is small. The ceiling-applied concrete layer 60 is post-casted after the construction of the ceiling structural frame 30.

  According to the radiation shielding structure 1 configured as described above, since the wall shielding member 20 and the ceiling shielding member 40 are formed separately, an iron plate (wall shielding) as in the conventional shielding structure (see FIG. 6). The structure part of the concrete is not divided and formed inside and outside the member and the ceiling shielding member). Therefore, the wall structure housing 10 may be formed only on one side of the wall shielding member 20 on the outdoor side, and the ceiling structure housing 30 may be formed only on the lower surface of the ceiling shielding member 40. This eliminates the need for an extra reinforced concrete structure for supporting the shielding member. Therefore, it is possible to reduce the labor required for constructing the shielding structure, and it is possible to reduce the material and the construction cost.

  Moreover, since the wall shielding member 20 and the ceiling shielding member 40 are provided separately, the load can be dispersed and efficiently borne in a balanced manner. Thereby, the amount of bar arrangement and the amount of concrete of the wall structure case 10 and the ceiling structure case 30 can be further reduced, and the construction cost can be reduced.

  Furthermore, since the wall structure housing 10 and the ceiling structure housing 30 are structurally integrally formed, they can be constructed at the same time, the construction labor can be reduced, and the workability can be improved.

  In the present embodiment, the wall radiation reflection preventing layer 50 is provided on the indoor side of the wall shielding member 20 so that the wall shielding member 20 is not exposed, so that reflection of radiation into the indoor side can be prevented. Further, even when the wall radiation antireflection layer 50 is formed of concrete, it is only necessary to provide a reinforcing bar or a mesh sheet that can prevent cracking and peeling of the concrete, and the wall radiation antireflection layer 50 needs to be a structure. Since there is not, the increase in the amount of bar arrangement can be suppressed.

  Furthermore, when the wall radiation antireflection layer 50 is thin, an extra reinforced concrete structure for supporting the shielding member is not necessary, and the wall shielding member 20 is disposed at a position closer to the wall surface with respect to the required indoor dimensions. can do. Accordingly, the distance between the wall shielding members 20 and 20 facing each other can be shortened, and the size of the ceiling shielding member 40 disposed above can be reduced. Therefore, the radiation shielding in the case of the high energy linac 3 is achieved. Efficient and compact. Therefore, the weight of the ceiling shielding member 40 can be reduced, the load acting on the ceiling structure housing 30 can be reduced, and the manufacturing cost of the ceiling shielding member 40 itself can be reduced.

  Next, the second best mode for carrying out the present invention will be described in detail with reference to FIGS. 4 and 5. FIG.

  The radiation shielding structure 1 ′ according to this embodiment includes a wall structure housing 15 made of reinforced concrete formed on an outdoor portion of a wall, a wall shielding member 25 erected on the indoor side of the wall structure housing 15, and a wall A ceiling structure casing 35 made of reinforced concrete is integrally formed on the top of the structure casing 15, and a ceiling shielding member 45 laid on the ceiling structure casing 35. In this embodiment, the reinforced concrete layer 55 is formed on both the indoor side and the outdoor side of the wall shielding member 25. Of the reinforced concrete layer 55 on both sides of the wall shielding member 25, the indoor side portion 55a of the wall shielding member 25 serves as a wall radiation reflection preventing layer. In addition, a ceiling-stretched concrete layer 65 is formed on the upper side of the ceiling shielding member 45.

  As shown in FIG. 4, the wall structure frame 15 is formed by placing the horizontal wall bars 11 and the vertical wall bars 12 at a predetermined pitch, and concrete 13 is placed at a predetermined thickness so as to cover them. Yes. The wall structure housing 15 is configured to have a bar arrangement amount and a thickness for providing structural strength, and is formed thinner than the wall structure housing 10 (see FIG. 1) of the first embodiment. The wall structure housing 15 is formed integrally with the pillar 16 (see FIG. 5).

  The wall shielding member 25 is configured by laminating iron plates to a predetermined thickness. The material and shape of the wall shielding member 25 are not limited to this. The wall shielding member 25 of the present embodiment is not formed with a protrusion as in the first embodiment, and has a flat surface from the lower end to the upper end. The wall shielding member 25 is erected at a predetermined interval from the indoor surface of the wall structure 15. The wall shielding member 25 has a lower end positioned below the floor surface and an upper end positioned substantially at the same height as the ceiling surface.

  As shown in FIGS. 4 and 5, the reinforced concrete layer 55 is formed on both the indoor side and the outdoor side of the wall shielding member 25. The reinforced concrete layer 55 may be formed of normal concrete or low activation concrete, like the wall radiation antireflection layer 50 (see FIG. 1) of the first embodiment. Reinforcing bars or mesh sheets (not shown) for preventing cracking and peeling of the concrete are provided on the indoor side portion 55a of the reinforced concrete layer 55 serving as a wall radiation antireflection layer. Reinforcing bars provided in the reinforced concrete layer 55 are for preventing cracking and peeling and not for structure, so that the amount of reinforcing bars is small. The reinforced concrete layer 55 may be placed at the same time as the wall structure 15 or after the wall structure 15 is constructed.

  On the other hand, in the reinforced concrete layer 55, the outdoor portion 55 b of the wall shielding member 25 serves to thicken the concrete on the outdoor side of the wall shielding member 25. That is, the thickness of the wall structure casing 15 of the present embodiment can support the ceiling structure casing 35, the ceiling shielding member 45, etc., but the radiation shielding performance is insufficient. Therefore, by forming the concrete layer 55 between the wall structure housing 15 and the outside of the wall shielding member 25, the outdoor portion 55b and the wall structure housing 15 are combined to provide the necessary radiation shielding performance. The concrete thickness that can be obtained is secured. In addition, the outdoor part 55b of the reinforced concrete layer 55 may be unreinforced.

  In the portion where the wall shielding member 25 is not provided, as shown in FIG. 5, the reinforced concrete layer 55 is equivalent to the combined thickness of the indoor portion 55a, the wall shielding member 25, and the outdoor portion 55b. It is formed in the thickness.

  As shown in FIG. 4, the upper structure 31 and the lower structure 32 are arranged at a predetermined pitch in the ceiling structure body 35, and concrete 33 is placed at a predetermined thickness so as to cover them. Is formed. The ceiling structure housing 35 has a flat upper end.

  The ceiling shielding member 45 is laid on the ceiling structure housing 35 and is arranged above the wall shielding member 25 with a predetermined interval. The ceiling shielding member 45 has a rectangular shape with a predetermined thickness, and is configured by stacking iron plates to a predetermined thickness. The short side portion of the ceiling shielding member 45 has the same length as the horizontal direction length of the wall shielding member 25. Moreover, the long side part of the ceiling shielding member 45 is longer than the distance between the outer surfaces of the wall shielding members 25 and 25 which oppose. That is, extending portions 45 a and 45 a that extend outward from the outer surface of the lower wall shielding member 25 are formed at both ends in the longitudinal direction of the ceiling shielding member 45. The extending portion 45a is such that a straight extension line (indicated by a one-dot chain line in FIG. 4) connecting the irradiation portion P and the indoor side upper end portion of the wall shielding member 25 intersects the extending portion 45a. The extension dimension is set. As a result, the radiation irradiated in the wall direction or the ceiling direction from the irradiating unit always strikes either the wall shielding member 25 or the ceiling shielding member 45 and is reliably shielded. In particular, even in the gap portion between the wall shielding member 25 and the ceiling shielding member 45, the radiation hits the extended portion 45 a of the ceiling shielding member 45 and leaks to the outside as shown by a one-dot chain line in FIG. 4. Absent.

  The ceiling reinforced concrete layer 65 is provided to prevent the upper surface of the ceiling shielding member 45 from being exposed. The ceiling reinforced concrete layer 65 is formed when there is a general room on the upper floor or when there is a rooftop facility. According to such a configuration, since the ceiling shielding member 45 is not exposed, scattering of radiation can be reduced. Moreover, since it is not necessary to make the ceiling-reinforced concrete into a structure, an increase in the amount of reinforcement can be suppressed. The reinforced concrete layer 65 is provided with reinforcing bars or mesh sheets (not shown) for preventing cracking and peeling of the concrete. Note that, in the portion where the ceiling shielding member 45 is not provided, the ceiling-reinforced concrete layer 65 is formed to a thickness equivalent to the combined thickness of the ceiling shielding member 45 and the ceiling-reinforced concrete layer 65 on the top thereof. ing.

  In this embodiment, the case where a general room is provided on the lower floor of the irradiation room 2 is shown, but in that case, the floor surface also needs to have radiation shielding performance. Therefore, the floor shielding member 80 is provided in the floor slab 17.

  The floor slab 17 is formed by placing upper and lower bars (not shown) at a predetermined pitch and placing concrete with a predetermined thickness so as to cover them. In the floor slab 17, a floor shielding member 80 is installed above the floor structure casing 81. The floor shielding member 80 is fixed to the floor structure 81 with an anchor or dropped onto the floor. Moreover, you may embed the floor shielding member 80 in concrete according to needs, such as finishing. The floor shielding member 80 is formed to a thickness that can obtain a desired radiation shielding performance.

  The floor shielding member 80 has a rectangular shape with a predetermined thickness, and is configured by stacking iron plates to a predetermined thickness. The short side portion of the floor shielding member 80 (the side extending in the front and back direction in FIG. 4) has the same length as the horizontal length of the wall shielding member 25. Further, the long side portion of the floor shielding member 80 (the side extending in the left-right direction in FIG. 4) is longer than the distance between the outer surfaces of the opposing wall shielding members 25 and 25. That is, extending portions 80 a and 80 a that extend outward from the outer surface of the upper wall shielding member 25 are formed at both ends in the longitudinal direction of the floor shielding member 80. The extending portion 80a has an extension dimension so that a straight extension line (not shown) connecting the irradiation portion P (not shown) and the lower end on the indoor side of the wall shielding member 25 always intersects the extending portion 80a. Is set. Since the floor shielding member 80 is disposed closer to the wall shielding member 25 than the ceiling shielding member 45, the extension dimension of the extension portion 80a is shorter than the extension portion 45a of the ceiling shielding member 45. That's it. With the configuration as described above, the radiation irradiated in the wall direction or the floor direction from the irradiating unit always hits either the wall shielding member 25 or the floor shielding member 80 and is reliably shielded.

  According to the radiation shielding structure 1 ′ having the above-described configuration, the wall structure housing 15 can be thinned in addition to the same effects as the first embodiment, so that the effect of reducing the labor and cost of construction can be achieved. can get. Further, according to the radiation shielding structure 1 ′ of the present embodiment, radiation shielding performance to the lower floor can be obtained.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to the said embodiment, In the range which does not deviate from the meaning of this invention, a design change is possible suitably. For example, in the said embodiment, although the shielding member of a wall and a ceiling is embed | buried under a part of a wall and a ceiling so that a radiation source may be enclosed, it is not limited to this. When the output of the radiation source is large, and when the projection plane of radiation extends in multiple directions, a wall shielding member, a ceiling shielding member, and a floor shielding member may be provided in the entire room. Furthermore, the radiation source is not limited to a high-energy linac, and can be applied to all radiation therapy apparatuses that form an irradiation surface.

It is the perpendicular direction sectional view showing the best first form for carrying out the radiation shielding structure concerning the present invention. It is the horizontal direction sectional view showing the best first form for carrying out the radiation shielding structure concerning the present invention. It is the perpendicular direction sectional view showing the best first form for carrying out the radiation shielding structure concerning the present invention. It is the perpendicular direction sectional view showing the best 2nd form for carrying out the radiation shielding structure concerning the present invention. It is horizontal direction sectional drawing which showed the best 2nd form for implementing the radiation shielding structure which concerns on this invention. It is the vertical direction sectional view showing the conventional radiation shielding structure.

Explanation of symbols

1 Radiation shielding structure 2 Irradiation room 3 High energy linac (radiation source)
DESCRIPTION OF SYMBOLS 10 Wall structure housing 20 Wall shielding member 21 Protrusion part 30 Ceiling structure housing 40 Ceiling shielding member 50 Wall radiation reflection prevention layer 60 Ceiling-increase concrete layer 1 'Radiation shielding structure 15 Wall structure housing 25 Wall shielding member 35 Ceiling structure housing 45 Ceiling structure housing 45 Shielding member 45a Extension part 55 Additional concrete layer 65 Ceiling additional concrete layer

Claims (4)

In the radiation shielding structure of the irradiation chamber that houses the high-energy linac as the radiation source,
The high-energy linac includes a rotatable gantry part and an irradiation part capable of emitting radiation from all angles toward the rotation center thereof,
The radiation shielding structure includes a gate-shaped reinforced concrete structure housing formed by integrally forming a wall structure housing and a ceiling structure housing.
The wall positioned in the radiation direction on both sides of the high energy linac on the indoor side of the wall structure housing is provided with a wall shielding member that shields radiation,
The wall shielding member is formed in a horizontal length capable of covering the distal end portion of the radiation irradiated laterally from the irradiation unit toward the wall,
The lower end of the wall shielding member is positioned below the floor surface, and the upper end is positioned at substantially the same height as the ceiling surface,
At the upper end of the wall shielding member, a protruding portion that protrudes indoors is formed over the entire length of the wall shielding member in the horizontal length direction ,
On the ceiling structure housing, a ceiling shielding member that shields radiation is separated from the wall shielding member, and is laid so as to cover an upper portion of a space between the wall shielding members facing each other ,
The ceiling shielding member has a rectangular shape, and one side portion has the same length as the horizontal length of the wall shielding member,
The wall shielding member and the ceiling shielding member are composed of any one of an iron plate, a lead plate, a polyethylene plate, or a boron-containing material plate,
The protrusion is a cross-sectional view in the vertical direction so that the radiation radiated linearly from the high-energy linac serving as the radiation source hits one of the ceiling shielding member, the wall shielding member, or the protrusion. And the radiation extended structure characterized by forming so that the linear extension line which connected the upper end part of the indoor side front-end | tip part of the protrusion part and the said irradiation part may cross | intersect the said ceiling shielding member . In the radiation shielding structure of the irradiation chamber that houses the high-energy linac as the radiation source,
The high-energy linac includes a rotatable gantry part and an irradiation part capable of emitting radiation from all angles toward the rotation center thereof,
The radiation shielding structure includes a gate-shaped reinforced concrete structure housing formed by integrally forming a wall structure housing and a ceiling structure housing.
The wall positioned in the radiation direction on both sides of the high energy linac on the indoor side of the wall structure housing is provided with a wall shielding member that shields radiation,
The wall shielding member is formed in a horizontal length capable of covering the distal end portion of the radiation irradiated laterally from the irradiation unit toward the wall,
The lower end of the wall shielding member is positioned below the floor surface, and the upper end is positioned at substantially the same height as the ceiling surface,
On the ceiling structure housing, a ceiling shielding member that shields radiation is separated from the wall shielding member, and is laid so as to cover an upper portion of a space between the wall shielding members facing each other ,
The ceiling shielding member has a rectangular shape, and one side portion has the same length as the horizontal length of the wall shielding member,
At the end portion of the ceiling shielding member on the wall structure housing side, an extending portion that extends outward from the outer surface of the wall shielding member is formed,
The wall shielding member and the ceiling shielding member are composed of any one of an iron plate, a lead plate, a polyethylene plate, or a boron-containing material plate,
The extension portion is vertically arranged so that the radiation radiated linearly from the high energy linac serving as the radiation source hits any one of the ceiling shielding member, the wall shielding member, or the extension portion. In a cross-sectional view, a linear extension line connecting the upper end portion on the indoor side of the wall shielding member on the side where the extension portion is located and the irradiation portion intersects the extension portion . A radiation shielding structure characterized by that. The radiation shielding structure according to claim 1, further comprising a wall radiation antireflection layer that is formed of concrete on the indoor side of the wall shielding member and prevents reflection of radiation. The radiation shielding structure according to any one of claims 1 to 3, further comprising a ceiling-reinforced concrete layer formed on an upper side of the ceiling shielding member.

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