Thomason C, Mackie T R, Lindstrom M J
Department of Medical Physics, University of Wisconsin, Madison 53705.
Phys Med Biol. 1991 Apr;36(4):495-505. doi: 10.1088/0031-9155/36/4/007.
The effect of source encapsulation on the energy spectra of 192Ir and 137Cs seed sources, both with stainless steel and with platinum encapsulation, was determined from results of Monte Carlo simulation. The fractional scatter dose around these sources has also been determined from Monte Carlo simulation. The platinum-encapsulated 192Ir source exhibited greater attenuation of the primary spectrum, as expected, and, consistent with this greater attenuation, exhibited more scattered radiation. Significantly less scatter was seen with the 137Cs source than with either 192Ir source, as is consistent with the higher-energy photons from 137Cs.
通过蒙特卡罗模拟结果，确定了源包壳对不锈钢和铂包壳的¹⁹²Ir及¹³⁷Cs籽源能谱的影响。还通过蒙特卡罗模拟确定了这些源周围的散射剂量分数。正如预期的那样，铂包壳的¹⁹²Ir源对初始能谱的衰减更大，并且与这种更大的衰减相一致，其散射辐射更多。与¹⁹²Ir源相比，¹³⁷Cs源的散射明显更少，这与¹³⁷Cs的高能光子一致。
