Dosimetry and quality specification of high energy photon beams.
Dosimetry and quality specification of high energy photon beams.
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高能光子束的剂量测定和质量规范。
DOI：
10.3109/02841868609136408
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
P. Andreo
中科院分区：
文献类型：
--
作者：
Anders Brahme;P. Andreo
定义了许多质量描述符来表征用于放射治疗的高能光子束的光子衰减和轻子污染特性。使用分析和蒙特卡罗技术对质量参数对临床射束设计的依赖性进行了一些详细分析，例如入射电子能量、目标和滤波器厚度、体模中的场尺寸和深度。结果表明，标准场尺寸 10 cm X 10 cm 的射束平均衰减系数与电离室剂量测定的平均阻止功率比非常精确地相关，但也近似与给定光子能量注量的射束中的平衡吸收剂量相关。这意味着可以在不知道所用光束的加速势、目标设计或滤波器厚度的情况下进行精确的光子剂量测定。此外，对体模中光束硬化和软化背后的机制进行了量化，并确定了轻子污染的合适质量参数。后者允许确定轻子污染，以便在污染较大时校正表面附近的阻止本领比。
A number of quality descriptors are defined characterizing the photon attenuation and lepton contamination properties of high energy photon beams for radiation therapy. The dependence of the quality parameters on the design of the clinical beams such as the incident electron energy, target and filter thicknesses, field size and depth in the phantom are analyzed in some detail using analytical and Monte Carlo techniques. It is shown that the mean attenuation coefficient of the beam for a standard field size of 10 cm X 10 cm is related very accurately to the mean stopping power ratio for ionizing chamber dosimetry but also approximately to the equilibrium absorbed dose in the beam for a given photon energy fluence. This means that accurate photon dosimetry can be performed without knowing the acceleration potential, target design or filter thickness for the beam in use. Furthermore, the mechanism behind beam hardening and softening in the phantom are quantitized and suitable quality parameters for the lepton contamination are identified. The latter allow a determination of the lepton contamination for correction of the stopping power ratio near the surface if the contamination is large.