Microbeam radiotherapy (MRT) is a novel preclinical RT, in which synchrotron-generated X-rays are segmented by a collimator, producing intense microbeams, tens of µm wide separated by hundreds of µm. MRT is well tolerated by normal tissues including the central nervous system in animal models when compared to conventional RT (CRT). Animal studies have produced long term survivors in MRT treated animals that were not seen in untreated or CRT-treated animals, strongly indicating better tumour control by MRT than by CRT.
A major goal of our current work is to develop an understanding of the biological mechanisms that underpin the differences in tissue response to MRT versus CRT. While dose equivalence between MRT and CRT remains a topic for debate, what is clear is that the molecular and cellular response of tissues and tumours to MRT is very different between these 2 radiation techniques. We have shown that gene expression profiles of tumour cells differ considerably both in vivo and in vitro after exposure to MRT versus CRT. The inflammatory response is more muted after MRT, and recent studies suggest significant differences in the local immune response following the 2 different types of radiation.
Our challenge is to understand and harness the favourable components of the differential tissue response to MRT to improve outcomes from both conventional and emerging radiotherapy treatments.