Bibbo Giovanni
S A Medical Imaging, Women's and Children's Hospital, 72 King William Road, North Adelaide, SA, 5006, Australia.
Australas Phys Eng Sci Med. 2017 Dec;40(4):925-930. doi: 10.1007/s13246-017-0586-7. Epub 2017 Oct 5.
The most widely accepted method for shielding design of X-ray facilities is that contained in the National Council on Radiation Protection and Measurements Report 147 whereby the computation of the barrier thickness for primary, secondary and leakage radiations is based on the knowledge of the distances from the radiation sources, the assumptions of the clinical workload, and usage and occupancy of adjacent areas. The shielding methodology used in this report is complex. With this methodology, the shielding designers need to make assumptions regarding the use of the X-ray room and the adjoining areas. Different shielding designers may make different assumptions resulting in different shielding requirements for a particular X-ray room. A more simple and practical method is to base the shielding design on the shielding principle used to shield X-ray tube housing to limit the leakage radiation from the X-ray tube. In this case, the shielding requirements of the X-ray room would depend only on the maximum radiation output of the X-ray equipment regardless of workload, usage or occupancy of the adjacent areas of the room. This shielding methodology, which has been used in South Australia since 1985, has proven to be practical and, to my knowledge, has not led to excess shielding of X-ray installations.
X射线设施屏蔽设计最广泛接受的方法包含在国家辐射防护与测量委员会第147号报告中，据此，一次、二次和泄漏辐射的屏蔽厚度计算基于与辐射源的距离、临床工作量假设以及相邻区域的使用和占用情况。本报告中使用的屏蔽方法很复杂。采用这种方法时，屏蔽设计师需要对X射线室和相邻区域的使用情况做出假设。不同的屏蔽设计师可能会做出不同的假设，从而导致特定X射线室的屏蔽要求不同。一种更简单实用的方法是基于用于屏蔽X射线管外壳以限制X射线管泄漏辐射的屏蔽原理进行屏蔽设计。在这种情况下，X射线室的屏蔽要求仅取决于X射线设备的最大辐射输出，而与房间相邻区域的工作量、使用情况或占用情况无关。自1985年以来在南澳大利亚使用的这种屏蔽方法已被证明是实用的，据我所知，它没有导致X射线装置的过度屏蔽。
