Ferreira I H, Bridier A, de Almeida C E, Marre D, Chavaudra J
Service de Physique, Institut Gustave Roussy, Villejuif, France.
Phys Med Biol. 1998 Oct;43(10):2721-7. doi: 10.1088/0031-9155/43/10/003.
The use of an ionization chamber for absorbed dose determinations in a medium requires one to take into account perturbation corrections due to the presence of the chamber cavity in the medium. Evaluation of these corrections for perturbation and their variation with depth in the medium has been performed for a flat cylindrical and a cylindrical (thimble-type) ionization chamber placed in a graphite phantom irradiated by a 60Co gamma beam using Monte Carlo calculations (EGS4 system with correlated sampling variance reduction technique). The results of these calculations agree with published experimental and theoretical data to better than 0.18%, with a statistical uncertainty of less than 0.17%.
在介质中使用电离室进行吸收剂量测定时，需要考虑由于电离室腔存在于介质中而产生的扰动校正。对于置于由钴 - 60伽马射线束辐照的石墨体模中的平板圆柱形电离室和圆柱形（指形）电离室，已使用蒙特卡罗计算（采用相关抽样方差减少技术的EGS4系统）对这些扰动校正及其在介质中随深度的变化进行了评估。这些计算结果与已发表的实验和理论数据相符，误差优于0.18%，统计不确定度小于0.17%。
