Dependence of LET on material and its impact on current RBE model.

Dependence of LET on material and its impact on current RBE model. Phys Med Biol. 2019 Apr 25;: Authors: Tan HQ, Koh WYC, Tan LKR, Phua JH, Ang KW, Park SY, Lew WS, Lee JCL Abstract Biological uncertainty remains one of the main sources of uncertainties
 in Proton Therapy, and is encapsulated in a scalar quantity known as Relative
 Biological Eective (RBE). It is currently recognized that a constant RBE of 1.1 is
 not consistent with radiobiological experiment and will lead to sub-optimal clinical
 outcome during treatment planning. To overcome this problem, several RBE models
 have been developed, and in most of these models, there is a dependence of RBE on
 dose-averaged Linear Energy Transfer (LET), LETd. In this work, we show that the
 LETd estimation in these models during the data-tting (or parameter estimation)
 phase could be subjected to huge uncertainty due to not taking into account cellular
 materials during simulation, and this uncertainty can propagate down to the resulting
 RBE models. The dosimetric impact of this LETd uncertainty is then evaluated
 on a simple clinical Spread Out Bread Peak (SOBP) and a prostate example. Our
 simulation shows that LETd uncertainty due to the use of water as cellular material is
 non-negligible under low (alpha/beta) ratio and low ...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research