Systemic effects of synchrotron radiation

A change in an organ or tissue distant from the irradiated region was termed the radiation-induced abscopal effect (RIAE). It is not known how radiation settings affect non-targeted normal tissues and therefore the risk of radiation-related adverse abscopal effects. In a recent study, we examined abscopal effects of microbeam radiotherapy (MRT) and broad beam (BB) configurations, in mice that were locally exposed to a very short pulse of a high dose-rate synchrotron beam utilizing the Imaging and Medical Beamline (IMBL) at the Australian Synchrotron. Here we summarise this study. Oxidative DNA damage was elevated in a wide variety of unirradiated normal tissues. Out-of-field duodenum showed a trend for elevated apoptotic cell death under most irradiation conditions, however, double-strand breaks (DSBs) elevated only after exposure to lower doses. These genotoxic events were accompanied by changes in concentrations of several plasma cytokines and in frequencies of macrophages, neutrophils and T-lymphocytes in duodenum. Overall, systemic radiation responses were independent of dose, time post-irradiation, and radiation modality. These findings have implications for the planning of therapeutic and diagnostic radiation treatment to reduce the risk of radiation-related adverse systemic effects.