Off-axis dose distribution for rectangle proton beam

• 来源期刊: 中国物理B(英文版)
• 关键词: proton radiotherapy Fermi-Eyges
• 年，卷（期）: 2008,（12）
• 页码范围: 4673-4676
• 页数: 4页
• 语种: 英文

摘要

This paper modifies an analytical algorithm originally developed for electron dose calculations to evaluate the off-axis dose distribution of rectangle proton beam. This spatial distribution could be described by Fermi-Eyges theory since a proton undergoes small-angle scattering when it passes through medium. Predictions of the algorithm for relative off-axis dose distribution by a 6 cm 6 cm initial monoenergetic proton beam are compared with the results from the published Monte Carlo simulations. The excellent levcl of agreement between the results of these two methods of dose calculation (＜ 2%) demonstrates that the off-axis dose distribution from rectangle proton beam may be computed with high accuracy using this algorithm. The results also prompts the necessity to consider the off-axis distribution when the proton is applied to clinical radiotherapy since the penumbra is significant at the distal of its range (about 0.6 cm at the Bragg-peak depth).