Particular consideration on radiation shielding of a CyberKnife room
10.3760/cma.j.cn112271-20220516-00206
- VernacularTitle:射波刀机房屏蔽的特殊考虑
- Author:
Jimian ZHANG
1
;
Zhongqing DU
;
Qiang ZENG
Author Information
1. 天津市疾病预防控制中心职业健康研究所，天津 300011
- Keywords:
CyberKnife;
Outer wall of bunker maze;
Verification;
Shielding design
- From:
Chinese Journal of Radiological Medicine and Protection
2022;42(11):892-896
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To verify radiation shielding effect of the maze of the CyberKnife room, so as to identify and correct the deficiencies in the shielding designs in certain circumstances.Methods:In line with the radiation protection shielding design scheme of the CyberKnife room provided by the producer, the consideradtions are focused on the useful beam that could mainly pass through the image center, but not the outer wall of the maze. However, during the inspection and acceptance of radiological protection in the built room, it was found that in a certain situations useful wire did not pass through the imaging center. Therefore, the additional shielding and protection facilities were built and verified.Results:After verification and acceptance on the scene, in the case where the useful beam was passing through the image center, the highest ambient dose equivalent rate at the concerned points 30 cm away from the outer wall of the maze was 0.31 μSv/h, less than the control level 10 μSv/h. In the opposite case, the highest ambient dose equivalent rate at the same points as above was 301.67 μSv/h, ablut 30 times as much as the control level. After the thickness in maze outer wall was enhanced, the highest ambient dose equivalent rate at the same as above was 2.14 μSv/h. This testing result met the concerned national standard.Conclusions:It is desirable that in designing the outer wall shielding in the maze in a CyberKnife room, attention should be paid to whether or not the useful beam could pass through the image center, or otherwise directly irradiate on the maze on the basis of the movement range of the accelerator. Shielding wall thickness should be calculated on the basis of the irradiation ragne and the distance between source location and the concerned points to ensure being in compliance with the requirements of the concerned national standard. Meanwhile, it should protect the workers occupying at the concerned locations from receiving higher radiation doses.
