Chen Y, Ahmad S
Department of Radiation Oncology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
Radiat Prot Dosimetry. 2012 Apr;149(2):116-23. doi: 10.1093/rpd/ncr218. Epub 2011 May 18.
A simple model for proton relative biological effectiveness (RBE) is proposed. It describes the RBE as a function of proton depth, the dose and the linear energy transfer (LET) when proton passes through tissue-like materials. Radiobiological parameters were first obtained by fitting the published experimental cell survival data. The dose-averaged LET values were calculated for 250-MeV proton beam in a water phantom by using GEANT4 Monte Carlo simulation code and were then used as input values to calculate the values of RBE as function of depths. The model was also applied to proton spread-out Bragg peak, where the increasing RBE with depth causes an extended RBE-weighted dose in the distal fall-off region. This model was found to be able to reproduce the measured RBE values as a function of LET, depth and dose for a specific cell line.
提出了一种质子相对生物效应（RBE）的简单模型。该模型将RBE描述为质子深度、剂量以及质子穿过类组织材料时的线能量转移（LET）的函数。首先通过拟合已发表的实验细胞存活数据获得放射生物学参数。使用GEANT4蒙特卡罗模拟代码计算了250 MeV质子束在水模体中的剂量平均LET值，然后将其用作输入值来计算RBE随深度变化的值。该模型还应用于质子扩展布拉格峰，其中RBE随深度增加导致远端剂量跌落区的RBE加权剂量延长。发现该模型能够再现特定细胞系的RBE值随LET、深度和剂量的变化情况。
