Abstract
Purpose Microbeam Radiotherapy (MRT) is a promising pre-clinical cancer therapy which represents a radical departure from the radiobiological principles of conventional radiotherapy (CRT). In order to translate MRT to human clinical trials, robust normal tissue toxicity data are required. This review summarizes the normal tissue effects reported by pre-clinical MRT animal studies and compares these data to clinical recommendations in CRT. Conclusion Few pre-clinical studies are specifically designed to evaluate the dose-response of normal tissue to MRT. However, it remains clear that a range of normal tissues can tolerate peak MRT doses at least an order of magnitude higher than CRT. Furthermore, the dose deposited in the valley regions, predominantly determined by microbeam spacing, has a greater influence on the normal tissue response to MRT compared to the peak regions. The development of a new normal tissue complication probability model for MRT, in conjunction with a treatment planning system, will be pivotal in the collection of robust normal tissue toxicity data and the translation of MRT to clinical use.
Disclosure statement
The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.
Funding information
SS is supported by an Early Career Research Fellowship from the National Health & Medical Research Council (NH&MRC) of Australia [1090906]. JCC is supported by an Early Career Research Fellowship from the NH&MRC of Australia [1036174]. LMLS is the recipient of an Australian Postgraduate Award scholarship. This work is supported by the NH&MRC of Australia [Project Grant 1061772] and Cancer Council Victoria [Grant-in-aid 2013].