Eakins J S, Baker S T, Gibbens N J, Gilvin P J, Hager L G, Tanner R J
Public Health England, Centre for Radiation Chemical and Environmental Hazards, Chilton, Didcot, Oxon OX11 0RQ, UK.
Radiat Prot Dosimetry. 2014 Jan;158(1):115-21. doi: 10.1093/rpd/nct195. Epub 2013 Aug 14.
In support of research aimed at developing a thermoluminescence dosemeter capable of accurately measuring ionising radiation doses to the lens of the eye, Monte Carlo modelling of a standard beta exposure set-up has been performed. It was found that electrons with an energy distribution corresponding to the beta emission spectrum from (85)Kr deposit negligible doses at a depth of 3 mm in tissue, but doses from (90)Sr/(90)Y are significant; free in air and fluence-to-Hp(3,θ°) and -Hp(0.07,θ°) conversion coefficient data were found for this field for exposures at 0°, 30° and 60° angles of incidence, and the response characteristics of the new eye dosemeter were evaluated. It was shown that the results were not affected greatly by the shape of the calibration phantom. However, it was demonstrated that the presence of intermediating air and beam flattening filters hardens the energy distribution of the field at the point of test, relative to a raw (90)Sr/(90)Y source, and this impacts dose depositions.
为支持旨在开发一种能够精确测量眼部晶状体电离辐射剂量的热释光剂量计的研究，已对标准β射线照射装置进行了蒙特卡罗建模。研究发现，能量分布与（85）Kr的β发射光谱相对应的电子在组织3毫米深度处沉积的剂量可忽略不计，但（90）Sr/（90）Y产生的剂量则较为显著；针对该场在0°、30°和60°入射角下的照射，获取了空气中的自由剂量以及通量到Hp(3,θ°)和-Hp(0.07,θ°)的转换系数数据，并评估了新型眼部剂量计的响应特性。结果表明，校准体模的形状对结果影响不大。然而，研究表明，相对于原始的（90）Sr/（90）Y源，中间空气和射束平坦化滤波器的存在会使测试点处场的能量分布变硬，这会影响剂量沉积。
