Thomason C, Higgins P
Department of Medical Physics, University of Wisconsin, Madison 53706.
Med Phys. 1989 Mar-Apr;16(2):254-7. doi: 10.1118/1.596420.
The radial dose distributions in water around 192Ir seed sources with both platinum and stainless steel encapsulation have been measured using LiF thermoluminescent dosimeters (TLD) for distances of 1 to 12 cm along the perpendicular bisector of the source to determine the effect of source encapsulation. Similar measurements also have been made around a 137Cs seed source of comparable dimensions. The data were fit to a third order polynomial to obtain an empirical equation for the radial dose factor which then can be used in dosimetry. The coefficients of this equation for each of the three sources are given. The radial dose factor of the stainless steel encapsulated 192Ir and that of the platinum encapsulated 192Ir agree to within 2%. The radial dose distributions measured here for 192Ir with either type of encapsulation and for 137Cs are indistinguishable from those of other authors when considering uncertainties involved. For clinical dosimetry based on isotropic point or line source models, any of these equations may be used without significantly affecting accuracy.
使用LiF热释光剂量计（TLD）测量了铂封装和不锈钢封装的192Ir籽源周围水中的径向剂量分布，测量距离为沿源垂直平分线1至12厘米，以确定源封装的影响。还对尺寸相当的137Cs籽源周围进行了类似测量。数据拟合为三阶多项式，以获得径向剂量因子的经验方程，该方程随后可用于剂量测定。给出了这三种源各自该方程的系数。不锈钢封装的192Ir和铂封装的192Ir的径向剂量因子在2%以内相符。考虑到所涉及的不确定性，这里测量的两种封装类型的192Ir以及137Cs的径向剂量分布与其他作者的结果没有区别。对于基于各向同性点源或线源模型的临床剂量测定，这些方程中的任何一个都可以使用，而不会显著影响准确性。
