JP2018179851A - Radiation shielding structure - Google Patents

Radiation shielding structure Download PDF

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JP2018179851A
JP2018179851A JP2017082018A JP2017082018A JP2018179851A JP 2018179851 A JP2018179851 A JP 2018179851A JP 2017082018 A JP2017082018 A JP 2017082018A JP 2017082018 A JP2017082018 A JP 2017082018A JP 2018179851 A JP2018179851 A JP 2018179851A
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radiation
maze
shielding
labyrinth
wall
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琢真 能任
Takuma Noto
琢真 能任
和明 小迫
Kazuaki Kosako
和明 小迫
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Shimizu Construction Co Ltd
Shimizu Corp
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Shimizu Construction Co Ltd
Shimizu Corp
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Abstract

PROBLEM TO BE SOLVED: To provide a radiation shielding structure capable of suppressing the direct incidence of radiation leaking from a radiation generator to a maze.SOLUTION: A radiation shielding structure 10 is equipped with a storage chamber 14 composed of a radiation shielding wall 22 storing a radiation generator 12 discharging radiation; an inlet/outlet port 16 of the storage chamber 14; and a maze 18 provided near the outlet/inlet port 16 in the storage chamber 14 so as to prevent the radiation from the radiation generator 12 from directly reaching the outlet/inlet port 16. At an opening 32 communicating a side on which the radiation generator 12 is placed and the inside of the maze 18, a shielding portion 34 for preventing at least a leakage line other than a use cone B discharged from the radiation generator 12 from directly entering the inside of the maze 18 is provided.SELECTED DRAWING: Figure 1

Description

本発明は、例えば医療用放射線遮蔽室のような迷路を備えた放射線遮蔽構造に関するものである。   The present invention relates to a radiation shielding structure provided with a labyrinth, for example a medical radiation shielding room.

従来、がん治療に使用される電子リニアック(直線加速器)等の放射線発生装置が設置された放射線遮蔽室では、放射線を遮蔽するためにコンクリートや鉄を使った厚い遮蔽壁で囲われている。しかし、遮蔽室の出入口は厚い遮蔽体を設けることができないため、迷路と呼ばれる形状を設けている。これにより、線源から出入口に直接届く放射線を迷路壁で遮蔽し、また、散乱により開口部を通過して到達する放射線に関しても、出入口に至るまでの距離と散乱を増やすことにより減衰させている。上記の過程により出入口に到達した放射線は、最終的に鉛やポリエチレンを含む遮蔽扉により遮蔽され、室外への漏洩を防いでいる。   Conventionally, in a radiation shielding room in which a radiation generator such as an electronic linac (linear accelerator) used for cancer treatment is installed, a thick shielding wall using concrete or iron is used to shield the radiation. However, since the entrance of the shielding chamber can not be provided with a thick shielding body, it has a shape called a maze. This shields the radiation that directly reaches the entrance from the radiation source with the maze wall, and also attenuates the radiation that reaches the entrance through the opening by scattering, by increasing the distance to the entrance and the scattering. . The radiation reaching the entrance through the above process is finally shielded by a shielding door containing lead and polyethylene to prevent leakage to the outside.

なお、従来の放射線遮蔽室の迷路構造としては、例えば特許文献1に記載の構造が知られている。この構造は、遮蔽扉から一次散乱面を見通せないように、迷路内に凸壁を設けたものである。   In addition, as a conventional maze structure of a radiation shielding room, the structure of patent document 1 is known, for example. This structure is provided with a convex wall in the maze so that the primary scattering surface can not be seen from the shielding door.

特開平5−223987号公報Unexamined-Japanese-Patent No. 5-223987

ところで、医療用リニアックでは、アイソセンター位置で治療用照射野の最大サイズが40×40cmになるように、照射口から放射線の利用線錘が照射される。一方、照射口以外のヘッド部分から利用線錘の1/1000以下の線量の漏洩線が放出される。 By the way, in the medical linac, a utilization pencil of radiation is irradiated from the irradiation port so that the maximum size of the therapeutic irradiation field is 40 × 40 cm 2 at the isocenter position. On the other hand, a leak line of a dose of 1/1000 or less of the used spindle is emitted from the head portion other than the irradiation port.

従来の遮蔽室の形状は、リニアックの照射口から利用線錘の一次散乱線が出入口に直接到達しないように迷路と出入口が配置されている。しかし、リニアックヘッドから漏洩するX線および中性子線に着目した迷路形状になっていないという問題があった。このため、リニアックヘッドから漏洩した放射線が迷路に直接入射して、迷路内の線量が上昇するおそれがあった。   The shape of the conventional shielding chamber is such that the labyrinth and the entrance are arranged so that the primary scattered radiation of the utilization pencil does not reach the entrance directly from the irradiation port of the linac. However, there is a problem that the labyrinth shape focusing on X-rays and neutrons leaking from the linac head is not formed. Therefore, radiation leaked from the linac head may be directly incident on the maze and the dose in the maze may increase.

本発明は、上記に鑑みてなされたものであって、放射線発生装置から漏洩した放射線が迷路に直接入射することを抑制することのできる放射線遮蔽構造を提供することを目的とする。   The present invention has been made in view of the above, and it is an object of the present invention to provide a radiation shielding structure capable of suppressing direct incidence of radiation leaked from a radiation generating apparatus into a maze.

上記した課題を解決し、目的を達成するために、本発明に係る放射線遮蔽構造は、放射線を放出する放射線発生装置を収容する放射線遮蔽壁からなる収容室と、この収容室の出入口と、放射線発生装置からの放射線が出入口に直接到達することを防ぐために収容室内において出入口の近傍に設けられた迷路とを備える放射線遮蔽構造であって、放射線発生装置のある側と迷路の内部とを連通する開口に、放射線発生装置から放出する少なくとも利用線錐以外の漏洩線が迷路の内部へ直接入射することを防ぐための遮蔽部が設けられていることを特徴とする。   In order to solve the above-mentioned problems and achieve the object, a radiation shielding structure according to the present invention comprises a storage chamber comprising a radiation shielding wall for storing a radiation generating device for emitting radiation, an inlet / outlet of the storage chamber, radiation A radiation shielding structure comprising a labyrinth provided in the vicinity of the port in the storage chamber to prevent radiation from the generator from directly reaching the port, which communicates the side with the radiation generator with the inside of the labyrinth It is characterized in that the opening is provided with a shielding portion for preventing direct incidence of leak lines other than at least the utilization line cone emitted from the radiation generator into the inside of the labyrinth.

また、本発明に係る他の放射線遮蔽構造は、上述した発明において、放射線発生装置のある側と迷路の内部とを仕切る位置に設けられ、端部側に開口を形成する迷路壁をさらに備え、遮蔽部は、この迷路壁の端部側に設けられていることを特徴とする。   Another radiation shielding structure according to the present invention is, in the above-mentioned invention, further provided with a labyrinth wall provided at a position for partitioning the side with the radiation generating device and the inside of the labyrinth and forming an opening on the end side. The shielding portion is characterized in that it is provided on the end side of the maze wall.

また、本発明に係る他の放射線遮蔽構造は、上述した発明において、遮蔽部は、迷路壁から放射線発生装置のある側に向けて突出していることを特徴とする。   Another radiation shielding structure according to the present invention is characterized in that, in the above-mentioned invention, the shielding portion protrudes from the maze wall toward the side where the radiation generating device is present.

本発明に係る放射線遮蔽構造によれば、放射線を放出する放射線発生装置を収容する放射線遮蔽壁からなる収容室と、この収容室の出入口と、放射線発生装置からの放射線が出入口に直接到達することを防ぐために収容室内において出入口の近傍に設けられた迷路とを備える放射線遮蔽構造であって、放射線発生装置のある側と迷路の内部とを連通する開口に、放射線発生装置から放出する少なくとも利用線錐以外の漏洩線が迷路の内部へ直接入射することを防ぐための遮蔽部が設けられているので、放射線発生装置から漏洩した利用線錐以外の漏洩線が迷路に直接入射することを抑制することができるという効果を奏する。   According to the radiation shielding structure relating to the present invention, the storage chamber consisting of the radiation shielding wall for storing the radiation generating device for emitting radiation, the entrance and exit of the storage chamber, and the radiation from the radiation generating device directly reach the entrance and exit Radiation shielding structure provided with a labyrinth provided in the vicinity of the entrance and exit in the storage chamber in order to prevent the radiation from being emitted from the radiation generating apparatus to the opening communicating between the side with the radiation generating apparatus and the inside of the labyrinth Since a shielding part is provided to prevent the leakage line other than the pyramid from directly entering the inside of the labyrinth, the leakage line other than the use line pyramid leaked from the radiation generating apparatus is prevented from directly entering the labyrinth The effect of being able to

また、本発明に係る他の放射線遮蔽構造によれば、放射線発生装置のある側と迷路の内部とを仕切る位置に設けられ、端部側に開口を形成する迷路壁をさらに備え、遮蔽部は、この迷路壁の端部側に設けられているので、放射線発生装置から漏洩した利用線錐以外の漏洩線が迷路内に直接入射するのを遮り、迷路内の放射線量の上昇を抑制することができるという効果を奏する。   Further, according to another radiation shielding structure according to the present invention, the shielding unit further includes a labyrinth wall provided at a position separating the side with the radiation generating apparatus and the inside of the labyrinth and forming an opening on the end side. Since it is provided on the end side of the maze wall, it blocks the direct incidence of leakage lines other than the use line pyramid leaked from the radiation generation device into the maze, and suppresses the increase of the radiation dose in the maze The effect of being able to

また、本発明に係る他の放射線遮蔽構造によれば、遮蔽部は、迷路壁から放射線発生装置のある側に向けて突出しているので、放射線発生装置から漏洩した利用線錐以外の漏洩線の開口への入射角度が狭くなり、迷路内の放射線量の上昇を効果的に抑制することができるという効果を奏する。   Further, according to another radiation shielding structure according to the present invention, since the shielding portion protrudes from the maze wall toward the side on which the radiation generating device is located, the leakage portion other than the use wire pyramid leaked from the radiation generating device. The angle of incidence to the aperture is narrowed, and the radiation dose in the maze can be effectively suppressed from rising.

図1は、本発明に係る放射線遮蔽構造の実施の形態を示す平面図であり、(1)は実施の形態1、(2)は実施の形態2である。FIG. 1 is a plan view showing an embodiment of a radiation shielding structure according to the present invention, where (1) is the first embodiment and (2) is the second embodiment. 図2は、本発明と従来例の相違点の説明図であり、(1)は実施例、(2)は従来例1、(3)は従来例2の場合である。FIG. 2 is an explanatory view of the difference between the present invention and the conventional example, where (1) is an example, (2) is a conventional example 1, and (3) is a conventional example. 図3は、本発明の効果を検証するために行った実施例の計算結果(X線実効線量率マップ)を示す図である。FIG. 3 is a diagram showing the calculation results (X-ray effective dose rate map) of the embodiment carried out to verify the effects of the present invention. 図4は、本発明の効果を検証するために行った比較例の計算結果(X線実効線量率マップ)を示す図である。FIG. 4 is a view showing a calculation result (X-ray effective dose rate map) of a comparative example performed to verify the effect of the present invention. 図5は、遮蔽扉前面における実効線量を示す図である。FIG. 5 shows the effective dose at the front of the shielding door.

以下に、本発明に係る放射線遮蔽構造の実施の形態を図面に基づいて詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。   Hereinafter, embodiments of a radiation shielding structure according to the present invention will be described in detail based on the drawings. The present invention is not limited by the embodiment.

図1(1)に示すように、本発明に係る放射線遮蔽構造10は、放射線を放出するリニアック12(放射線発生装置)を収容する収容室14と、この収容室14の出入口16と、出入口16の近傍に設けられた迷路18と、迷路壁28の端部30に設けられた遮蔽部34とを備える。出入口16には放射線を遮蔽する機能を有する遮蔽扉20が設けられる。   As shown in FIG. 1 (1), the radiation shielding structure 10 according to the present invention comprises a storage chamber 14 for storing a linac 12 (a radiation generating device) for emitting radiation, an inlet / outlet 16 of the storage chamber 14, and an inlet / outlet 16. And a shielding portion 34 provided at an end 30 of the maze wall 28. The entrance 16 is provided with a shielding door 20 having a function of shielding radiation.

本実施の形態のリニアック12は、放射線によって患部を照射するために用いる医療用リニアックを想定している。したがって、収容室14は、医療用リニアックが設置される照射室に相当する。   The linac 12 of the present embodiment assumes a medical linac used to irradiate the affected area with radiation. Therefore, the storage chamber 14 corresponds to an irradiation chamber in which a medical linac is installed.

リニアック12はリニアックヘッドHを備えており、このヘッドH内に設けた図示しないターゲットに、例えば10MeVのエネルギーで加速された粒子を衝突させることで、光子や電子ビームなどの放射線を発生させるようになっている。ターゲットで発生した放射線は、コリメータなどにより絞られて患部性状に応じた利用線錐Bとなり、アイソセンター位置Pの患者の患部に照射される。リニアックヘッドHは、治療台上などに設定したアイソセンター位置Pを中心として所定方向(例えば鉛直軸周り)に360°回動可能に構成されており、リニアックヘッドHの回動軌道上の任意位置からアイソセンター位置Pに対して、放射線の照射を行う。   The linac 12 is provided with a linac head H so that, for example, by causing particles accelerated with an energy of 10 MeV to collide with a target (not shown) provided in the head H, radiation such as photons or electron beams is generated. It has become. The radiation generated at the target is narrowed by a collimator or the like to form a use line cone B according to the property of the affected area, and is applied to the affected area of the patient at the isocenter position P. The linac head H is configured to be able to rotate 360 ° in a predetermined direction (for example, around a vertical axis) about an isocenter position P set on a treatment table or the like, and any position on the rotation track of the linac head H Radiation is irradiated to the isocenter position P.

収容室14は、リニアックヘッドHから放射される放射線を遮蔽するために放射線遮蔽壁22により囲まれた平面視で矩形状の部屋となっている。この放射線遮蔽壁22は、鉄などの金属とこれを覆うコンクリートとから構成されている。なお、利用線錐Bの延長上の壁内部には、放射線遮蔽能力に優れた鉄などの金属板24が埋め込まれている。   The storage chamber 14 is a rectangular chamber in a plan view surrounded by the radiation shielding wall 22 to shield the radiation emitted from the linac head H. The radiation shielding wall 22 is made of metal such as iron and concrete covering the metal. In the inside of the wall on the extension of the utilization line cone B, a metal plate 24 such as iron having an excellent radiation shielding ability is embedded.

迷路18は、リニアック12からの放射線が出入口16に直接到達することを防ぐために設けられる。より具体的には、迷路壁28が、正面側10Aの放射線遮蔽壁22から収容室14内部に向けて垂直に突設されており、リニアック12のある側と迷路18の内部26とを仕切っている。この迷路壁28と側面側10Bの放射線遮蔽壁22との間に迷路18が形成される。迷路壁28の端部30と背面側の放射線遮蔽壁22との間には開口32が形成され、この開口32は、リニアック12のある側と迷路18の内部26とを連絡する通用口として使用される。   A labyrinth 18 is provided to prevent radiation from the linac 12 from directly reaching the entrance 16. More specifically, the labyrinth wall 28 projects vertically from the radiation shielding wall 22 on the front side 10A toward the inside of the storage chamber 14 and divides the side with the linac 12 and the inside 26 of the labyrinth 18 There is. A maze 18 is formed between the maze wall 28 and the radiation shielding wall 22 on the side 10B. An opening 32 is formed between the end 30 of the labyrinth wall 28 and the radiation shielding wall 22 on the back side, and this opening 32 is used as a through hole to communicate the side with the linac 12 and the inside 26 of the labyrinth 18 Be done.

なお、図の例では、迷路壁28の端部30は、開口32に近づくにつれ次第に壁厚が薄くなるように迷路18の内部26側に傾斜が付けられた形態となっている。また、迷路18を挟んで迷路壁28に対向する側面側の放射線遮蔽壁22についても、これに対応した傾斜が付けられた形態となっている。   In the illustrated example, the end 30 of the labyrinth wall 28 is inclined toward the inside 26 of the labyrinth 18 so that the wall thickness gradually decreases as the opening 32 is approached. Further, the radiation shielding wall 22 on the side facing the maze wall 28 across the maze 18 is also inclined in accordance with this.

遮蔽部34は、リニアックヘッドHから放出する利用線錐B以外の漏洩線L(例えばX線や中性子線など)が迷路18の内部26へ直接入射することを防ぐためのものであり、迷路壁28の端部30に設けられる。この遮蔽部34は、放射線遮蔽壁22と同様の材料で構成することができる。また、遮蔽部34は、迷路壁28の一部として構成することもできる。   The shielding part 34 is for preventing the leak line L (for example, X-ray, neutron beam, etc.) other than the utilization ray cone B emitted from the linac head H from being directly incident on the inside 26 of the maze 18, and the maze wall It is provided at the end 30 of 28. The shielding portion 34 can be made of the same material as the radiation shielding wall 22. Alternatively, the shield 34 may be configured as part of the maze wall 28.

遮蔽部34は、迷路壁28からリニアック12のある側に向けて突出している。遮蔽部34を突出して設けることで、リニアックヘッドHから漏洩した漏洩線Lの開口32への入射角度が狭くなり、迷路18内に直接入射する放射線を減弱することができる。これにより、迷路18内の放射線量の上昇を効果的に抑制し、放射線量を低減することができる。また、出入口16に到達する放射線量が低減するため、遮蔽扉20の扉体厚を薄くし、軽量化することが可能となり、建設コストを低減することができる。   The shield 34 protrudes from the maze wall 28 toward the side on which the linac 12 is located. By providing the shielding portion 34 in a protruding manner, the incident angle of the leaked line L leaked from the linac head H to the opening 32 can be narrowed, and radiation directly entering the maze 18 can be attenuated. Thereby, the rise of the radiation dose in the maze 18 can be effectively suppressed and the radiation dose can be reduced. In addition, since the radiation amount reaching the entrance 16 is reduced, it is possible to reduce the thickness and weight of the shielding door 20, thereby reducing the construction cost.

なお、上記の実施の形態では、出入口16を放射線遮蔽構造10の正面側10Aに設けた例を説明したが、本発明の出入口の位置、向きはこれに限るものではない。例えば、図1(2)に示すように、放射線遮蔽構造10の側面側10Bに出入口16を設け、迷路18の内部の通路が鍵状になるように構成してもよい。このようにしても、上記と同様の作用効果を奏することができる。   In the above embodiment, an example in which the inlet / outlet 16 is provided on the front side 10A of the radiation shielding structure 10 has been described, but the position and direction of the outlet according to the present invention are not limited thereto. For example, as shown in FIG. 1 (2), the entrance 16 may be provided on the side 10B of the radiation shielding structure 10 so that the passage inside the labyrinth 18 is shaped like a key. Even in this case, the same function and effect as the above can be obtained.

次に、本発明と従来例の相違点について図2を参照しながら説明する。   Next, differences between the present invention and the prior art will be described with reference to FIG.

図2(1)は本発明の実施例、(2)は従来例1、(3)は従来例2の説明図である。図2(1)に示すように、本発明の実施例では、迷路壁18の端部30にリニアック12側に突き出た遮蔽部34を設けている。こうすることで、リニアックヘッドHからの漏洩線Lの入射角度を狭めることができる。   FIG. 2 (1) is an explanatory view of an embodiment of the present invention, (2) is a prior art example 1, and (3) is a prior art example 2. As shown in FIG. 2 (1), in the embodiment of the present invention, the end 30 of the maze wall 18 is provided with a shielding portion 34 protruding toward the linac 12. By doing this, the incident angle of the leaked line L from the linac head H can be narrowed.

一方、従来例1においても、図2(2)に示すように、迷路壁18の端部30にリニアック12側に突き出た突出部36を設けている。しかし、この突出部36は利用線錘Bの遮蔽を目的とするものであり、漏洩線の遮蔽を目的とするものではない。したがって、この従来例1では、漏洩線の入射角度を狭めることはできず、漏洩線が開口32へ直接入射することを許容してしまう。また、従来例2では、図2(2)に示すように、迷路壁18の端部30に突出部38を設けている。この従来例2では利用線錘Bの一次散乱線Sの入射角度を狭めることができる。しかし、従来例1と同様に、漏洩線の入射角度を狭めることはできず、漏洩線が開口32へ直接入射することを許容してしまう。   On the other hand, also in the first prior art, as shown in FIG. 2 (2), the end portion 30 of the maze wall 18 is provided with the protruding portion 36 protruding toward the linac 12 side. However, this protrusion 36 is intended to shield the use spindle B, and is not intended to shield the leaked wire. Therefore, in the first prior art, the incident angle of the leaked wire can not be narrowed, and the leaked wire is allowed to directly enter the opening 32. Further, in the second conventional example, as shown in FIG. 2 (2), the projecting portion 38 is provided at the end 30 of the maze wall 18. In this prior art example 2, the incident angle of the primary scattered ray S of the utilization spindle B can be narrowed. However, as in the prior art example 1, the incident angle of the leaked wire can not be narrowed, and the leaked wire is allowed to directly enter the opening 32.

このように、従来例1、2の迷路の形状は、一見すると本実施例と同一または類似の形状であるが、これら従来例1、2は利用線錘Bおよびその一次散乱線Sの遮蔽・減衰が目的となっており、漏洩線Lの入射角度を狭めるという観点からの形状となっていない。   Thus, the shape of the labyrinths of Conventional Examples 1 and 2 seemingly the same as or similar to the shape of the present embodiment, however, these Conventional Examples 1 and 2 have shielding of the use spindle B and its primary scattered radiation S. The purpose is attenuation, and the shape is not in view of narrowing the incident angle of the leak line L.

利用線錘Bの方向を確認すれば、突出部(本発明の遮蔽部に相当)の目的を確認することが可能である。より具体的には、収容室14の出入口16における実効線量が一番大きくなるリニアックヘッドHの向きにおいて、利用線錘Bと、迷路方向に散乱した利用線錘Bの一次散乱線Sを平面図上に作図した場合、突出部の有無によりこれらが変化するものは従来例に相当し、これらが変化しないものの、ヘッドHからの漏洩線Lの直接入射を狭めることができるものは本発明の技術的範囲と判断することができる。   If the direction of the use spindle B is confirmed, it is possible to confirm the purpose of the projecting portion (corresponding to the shielding portion of the present invention). More specifically, in the direction of the linac head H in which the effective dose at the entrance 16 of the storage chamber 14 is largest, a plan view of the use spindle B and the primary scatter line S of the use spindle B scattered in the maze direction When the drawing is made on the above, those which change depending on the presence or absence of the projecting part correspond to the conventional example, and although these do not change, those which can narrow the direct incidence of the leaked line L from the head H are the techniques of the present invention It can be judged as the target range.

(本発明の効果の検証)
次に、本発明の効果を検証するために行った計算結果について説明する。
(Verification of the effect of the present invention)
Next, calculation results performed to verify the effects of the present invention will be described.

本計算は、収容室14内のX線実効線量と中性子線実効線量の分布状況を、後述の計算コードを用いて計算したものである。計算ケースは、迷路壁28の端部30に遮蔽部34としての突出部を設けた場合(実施例)と、迷路壁28の端部30に突出部を設けない場合(比較例)とした。迷路壁28の端部30と放射線遮蔽壁22とにより形成される開口32の幅は同じとし、実施例における突出部の大きさ(幅×突出長)は、50cm×50cmと、100cm×100cmの2ケースとした。   In this calculation, the distribution of the X-ray effective dose and the neutron effective dose in the storage chamber 14 is calculated using a calculation code described later. In the calculation case, the end 30 of the maze wall 28 is provided with a protruding portion as the shielding portion 34 (example) and the end 30 of the maze wall 28 is not provided with a protruding portion (comparative example). The width of the opening 32 formed by the end 30 of the maze wall 28 and the radiation shielding wall 22 is the same, and the size (width × protruding length) of the protrusion in the embodiment is 50 cm × 50 cm and 100 cm × 100 cm. It was 2 cases.

また、計算条件は以下のとおりとした。
計算コード:モンテカルロ計算コードMCNP5
線源:10MeV電子ビーム
ターゲット:銅(1.5cm厚)
コリメータ:タングステン
断面積ライブラリ:光子と電子の相互作用 MCPLIB04,EL03
中性子相互作用 FSXLIB−J40
光核反応 LA150
The calculation conditions are as follows.
Calculation code: Monte Carlo calculation code MCNP5
Source: 10 MeV Electron Beam Target: Copper (1.5 cm thick)
Collimator: Tungsten Cross-section Library: Photon-electron interaction MCPLIB04, EL03
Neutron interaction FSXLIB-J40
Photonuclear reaction LA150

図3に実施例(100cm×100cm)のX線の線量マップを、図4に比較例のX線の線量マップを、図5に線量マップの評価点(遮蔽扉前面)における実効線量のグラフを示す。これらの図に示すように、突出部を設けることにより、遮蔽扉前面の実効線量が減少することが確認できる。特に100cm×100cmの突出部を設けた場合、X線を8.2%、中性子線を16.9%、合計で8.4%減少できることが確認できる。   Fig. 3 X-ray dose map of Example (100 cm x 100 cm), Fig. 4 X-ray dose map of the comparative example, Fig. 5 graph of effective dose at the evaluation point of dose map (front of shielding door) Show. As shown in these figures, it can be confirmed that the effective dose on the front of the shielding door is reduced by providing the projection. In particular, in the case of providing a projection of 100 cm × 100 cm, it can be confirmed that the X-ray can be reduced by 8.2% and the neutron beam can be reduced by 16.9%, for a total of 8.4%.

以上説明したように、本発明に係る放射線遮蔽構造によれば、放射線を放出する放射線発生装置を収容する放射線遮蔽壁からなる収容室と、この収容室の出入口と、放射線発生装置からの放射線が出入口に直接到達することを防ぐために収容室内において出入口の近傍に設けられた迷路とを備える放射線遮蔽構造であって、放射線発生装置のある側と迷路の内部とを連通する開口に、放射線発生装置から放出する少なくとも利用線錐以外の漏洩線が迷路の内部へ直接入射することを防ぐための遮蔽部が設けられているので、放射線発生装置から漏洩した利用線錐以外の漏洩線が迷路に直接入射することを抑制することができる。   As described above, according to the radiation shielding structure of the present invention, the radiation from the radiation generating device is a storage chamber formed of a radiation shielding wall for receiving the radiation generating device for emitting radiation, the entrance and exit of the storage chamber, and radiation from the radiation generating device. A radiation shielding structure comprising: a labyrinth provided in the vicinity of the entrance and exit in the storage chamber to prevent direct access to the entrance and exit, wherein the opening communicating the side with the radiation generating apparatus and the inside of the labyrinth Since the shielding part is provided to prevent the leak line other than at least the use line cone emitted from the radiation from directly entering the inside of the maze, the leak line other than the use line cone leaked from the radiation generating apparatus is directly transmitted to the maze Incident can be suppressed.

また、本発明に係る他の放射線遮蔽構造によれば、放射線発生装置のある側と迷路の内部とを仕切る位置に設けられ、端部側に開口を形成する迷路壁をさらに備え、遮蔽部は、この迷路壁の端部側に設けられているので、放射線発生装置から漏洩した利用線錐以外の漏洩線が迷路内に直接入射するのを遮り、迷路内の放射線量の上昇を抑制することができる。   Further, according to another radiation shielding structure according to the present invention, the shielding unit further includes a labyrinth wall provided at a position separating the side with the radiation generating apparatus and the inside of the labyrinth and forming an opening on the end side. Since it is provided on the end side of the maze wall, it blocks the direct incidence of leakage lines other than the use line pyramid leaked from the radiation generation device into the maze, and suppresses the increase of the radiation dose in the maze Can.

また、本発明に係る他の放射線遮蔽構造によれば、遮蔽部は、迷路壁から放射線発生装置のある側に向けて突出しているので、放射線発生装置から漏洩した利用線錐以外の漏洩線の開口への入射角度が狭くなり、迷路内の放射線量の上昇を効果的に抑制することができる。   Further, according to another radiation shielding structure according to the present invention, since the shielding portion protrudes from the maze wall toward the side on which the radiation generating device is located, the leakage portion other than the use wire pyramid leaked from the radiation generating device. The incident angle to the opening is narrowed, and the radiation dose increase in the maze can be effectively suppressed.

以上のように、本発明に係る放射線遮蔽構造は、医療用放射線遮蔽室などの迷路を備える放射線利用施設に有用であり、特に、放射線発生装置から漏洩した放射線が迷路に直接入射することを抑制するのに適している。   As described above, the radiation shielding structure according to the present invention is useful for a radiation utilization facility provided with a labyrinth such as a medical radiation shielding room, and in particular, the radiation leaked from the radiation generating apparatus is prevented from being directly incident on the labyrinth It is suitable for

10 放射線遮蔽構造
10A 正面側
10B 側面側
12 リニアック(放射線発生装置)
14 収容室
16 出入口
18 迷路
20 遮蔽扉
22 放射線遮蔽壁
24 金属板
26 内部
28 迷路壁
30 端部
32 開口
34 遮蔽部
36,38 突出部
B 利用線錐
H リニアックヘッド
L 漏洩線
P アイソセンター位置
S 一次散乱線
10 radiation shielding structure 10A front side 10B side side 12 linac (radiation generator)
14 accommodation room 16 entrance 18 maze 20 shielding door 22 radiation shielding wall 24 metal plate 26 inside 28 maze wall 30 end 32 opening 34 shielding part 36, 38 projecting part B use wire cone H linac head L leak line P isocenter position S Primary scattered radiation

Claims (3)

放射線を放出する放射線発生装置を収容する放射線遮蔽壁からなる収容室と、この収容室の出入口と、放射線発生装置からの放射線が出入口に直接到達することを防ぐために収容室内において出入口の近傍に設けられた迷路とを備える放射線遮蔽構造であって、
放射線発生装置のある側と迷路の内部とを連通する開口に、放射線発生装置から放出する少なくとも利用線錐以外の漏洩線が迷路の内部へ直接入射することを防ぐための遮蔽部が設けられていることを特徴とする放射線遮蔽構造。
A storage chamber comprising a radiation shielding wall for storing a radiation generating device for emitting radiation, an inlet / outlet of the storage chamber, and an opening in the storage chamber for preventing radiation from the radiation generator from directly reaching the inlet / outlet A radiation shielding structure comprising:
At the opening that communicates the side with the radiation generator and the inside of the labyrinth, a shield is provided to prevent direct entry into the interior of the labyrinth of leak lines other than at least the use cones emitted from the radiation generator. Radiation shielding structure characterized in that
放射線発生装置のある側と迷路の内部とを仕切る位置に設けられ、端部側に開口を形成する迷路壁をさらに備え、遮蔽部は、この迷路壁の端部側に設けられていることを特徴とする請求項1に記載の放射線遮蔽構造。   There is further provided a labyrinth wall provided at a position separating the side with the radiation generating apparatus and the inside of the labyrinth and forming an opening at the end side, and the shielding portion is provided at the end side of this labyrinth wall The radiation shielding structure according to claim 1, characterized in that 遮蔽部は、迷路壁から放射線発生装置のある側に向けて突出していることを特徴とする請求項2に記載の放射線遮蔽構造。   The radiation shielding structure according to claim 2, wherein the shielding portion protrudes from the maze wall toward a side on which the radiation generating device is present.
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