体模中用于光子剂量测定的电离室的有效测量点

Effective measuring point of ion chambers for photon dosimetry in phantoms.

作者信息

Zoetelief J, Engels A C, Broerse J J

出版信息

Br J Radiol. 1980 Jun;53(630):580-3. doi: 10.1259/0007-1285-53-630-580.

Abstract

The effective point of measurement for spherical ionization chambers has been determined for 60Co and 137Cs gamma rays and for 300 kV X rays inside a water phantom. For reasons of comparison, measurements were also performed with a thimble-type Baldwin-Farmer ion chamber. For spherical ion chambers the displacement correction factors were 1-(0.37 +/- 0.04) r. 10(-2) for 60Co gamma rays and 1-(0.22 +/- 0.05) r. 10(-2) for 137 Cs gamma rays, where r is expressed in mm, whereas no displacement was observed for X rays. The differences in displacement obtained for the various types of radiation can be attributed to differences in attenuation and scatter characteristics of the various radiation qualities.

摘要

已确定在水模体中针对60Co和137Csγ射线以及300 kV X射线的球形电离室的有效测量点。出于比较目的，还使用针箍型鲍德温 - 法默电离室进行了测量。对于球形电离室，60Coγ射线的位移校正因子为1 - (0.37 ± 0.04)r×10⁻²，137Csγ射线的位移校正因子为1 - (0.22 ± 0.05)r×10⁻²，其中r以毫米为单位表示，而对于X射线未观察到位移。不同类型辐射所获得的位移差异可归因于各种辐射质的衰减和散射特性的差异。