Pradhan A S, Gambhir S P, Patel P H, Bhatt R C, Supe S J
Division of Radiological Protection, Bhabha Atomic Research Center, Bombay, India.
Health Phys. 1990 Sep;59(3):299-304. doi: 10.1097/00004032-199009000-00005.
In personnel monitoring, operational quantities recommended by ICRU Publication No. 39 for photon radiation can be realized by calibrating dosimeters on a phantom and considering body backscatter photons by using established conversion factors. Personnel dosimeters used in this study are based on CaSO4:Dy Teflon thermoluminescence dosimeter discs (TLD) that have a highly photon energy-dependent response. Since body backscattered photons have lower energies than the incidence photons, methods for correcting for energy dependence of both the incident and body backscattered photons have to be developed. By using readouts of two TLD discs (one under a composite metal filter and the other without a metal filter) in an empirical relation valid at all energies, it is possible to correct for the effect of change in response from change in the photon energies. It was found that the new operational quantities recommended by ICRU could be estimated to within +/- 15% by a TLD badge design based on this method. Angular dependence limits for photons in accordance with the new international standards and a high beta dose-equivalent discrimination in the mixed fields of beta and low-energy x rays could also be achieved.
在人员监测中，国际辐射单位与测量委员会第39号出版物推荐的用于光子辐射的操作量，可以通过在体模上校准剂量计并利用既定的转换因子考虑人体反向散射光子来实现。本研究中使用的人员剂量计基于硫酸钙:镝聚四氟乙烯热释光剂量计圆盘（TLD），其对光子能量的响应高度依赖。由于人体反向散射光子的能量低于入射光子，因此必须开发校正入射光子和人体反向散射光子能量依赖性的方法。通过在一个对所有能量都有效的经验关系式中使用两个TLD圆盘（一个置于复合金属滤片下，另一个无金属滤片）的读数，可以校正光子能量变化引起的响应变化的影响。结果发现，基于这种方法的TLD徽章设计能够将国际辐射单位与测量委员会推荐的新操作量估计在±15%以内。还可以实现符合新国际标准的光子角度依赖性限制以及在β射线和低能X射线混合场中的高β剂量当量辨别。
