Zoetelief J, Broerse J J
Phys Med Biol. 1983 May;28(5):503-20. doi: 10.1088/0031-9155/28/5/005.
The use of calibrated tissue-equivalent (TE) ionisation chambers is commonly considered to be the most practical method for total absorbed dose determinations in mixed neutron-photon fields for biomedical applications. The total absorbed dose can be derived from the charge produced within the cavity of an ionisation chamber employing a number of physical parameters. To arrive at the charge produced in the cavity several correction factors have to be introduced which are related to the operational characteristics of the chambers. Information on the operational characteristics of four TE ionisation chambers is presented in relation to ion collection, density and composition of gas in the cavity, wall thickness and effective point of measurement. In addition, some recent results from an ionisation chamber operated at high gas pressures (up to 8 MPa(80 bar)) are presented. The total absorbed doses derived from TE ionisation chambers show agreement within the uncertainty limits with results from other independent dosimetry methods, i.e., differential fluence measurements and a TE calorimeter. Conscientious experimentation and a common data base can provide dosimetry results with TE ionisation chambers with variations of less than +/- 2%.
对于生物医学应用中混合中子 - 光子场的总吸收剂量测定，使用校准的组织等效（TE）电离室通常被认为是最实用的方法。总吸收剂量可以通过采用一些物理参数，从电离室腔体内产生的电荷推导得出。为了得到腔体内产生的电荷，必须引入一些与电离室操作特性相关的校正因子。本文介绍了四种TE电离室在离子收集、腔体内气体密度和成分、壁厚度以及有效测量点方面的操作特性信息。此外，还给出了一个在高气压（高达8兆帕（80巴））下运行的电离室的一些最新结果。由TE电离室得出的总吸收剂量在不确定度范围内与其他独立剂量测定方法（即微分注量测量和TE量热计）的结果一致。认真的实验和通用数据库能够提供变化小于±2%的TE电离室剂量测定结果。
