Stasi M, Baiotto B, Barboni G, Scielzo G
Medical Physics Department, Institute for Cancer Research and Treatment, 10060 Candiolo, Torino, Italy.
Med Phys. 2004 Oct;31(10):2792-5. doi: 10.1118/1.1788911.
The aim of this work is to compare different ion chambers available for dose measurements in small fields used in intensity modulated radiotherapy. Some dosimetric aspects, related to these small radiation fields, i.e., lack of electronic lateral equilibrium and steep dose region, must be evaluated, in order to obtain an accurate technique implementation. Furthermore, the size of the sensitive volume of the chambers compared with the mapping of the beams or segments needs consideration. If the size of the chamber is too large for the flatness of the field, the measurement can deviate from the expected absorbed dose at a point. We propose a comparison of various dosimetric values between different microionization chambers with respect to a smaller dosimeter, such as the diamond detector.
这项工作的目的是比较适用于调强放射治疗中小射野剂量测量的不同电离室。为了实现精确的技术实施，必须评估与这些小辐射野相关的一些剂量学方面，即缺乏电子横向平衡和陡峭的剂量区域。此外，还需要考虑电离室灵敏体积的大小与射束或射野分段的映射关系。如果电离室的尺寸对于射野的平坦度来说太大，测量值可能会偏离某一点处预期的吸收剂量。我们建议针对一种较小的剂量计（如金刚石探测器），比较不同微电离室之间的各种剂量学值。
