Abstract
AbstractPurpose: To investigate biochemical changes in mouse tumour tissue following Microbeam Radiation Therapy (MRT) and Broad Beam (BB) irradiation using synchrotron Fourier-Transform Infrared (FTIR) microspectroscopy.Materials and methods: Synchrotron FTIR microspectroscopy was carried out on mouse tumour sections previously irradiated with BB (11, 22 or 44 Gy), MRT (560 Gy in-beam, 25 μm wide, 200 μm peak separation) or sham-irradiation (0 Gy) from mice culled 4 hours post-irradiation.Results: MRT and BB-irradiated tumour sections showed clear chemical shifts in spectral bands corresponding to functional group vibrations in protein (1654–1630 cm−1), lipid (~1470, 1463 cm−1) and nucleic acid (1130–1050 cm−1). MRT peak and valley regions showed virtually identical absorbance patterns in protein and lipid regions. However, we observed chemical shifts corresponding to the nucleic acid region (1120–1050 cm−1) between the peak and valley dose regions. Chemical maps produced from integrating absorbance bands of interest over the scanned tumour area did not reveal any microbeam paths.Conclusions: The lack of difference between MRT peak and valley irradiated areas suggests a holistic tissue response to MRT that occurs within 4 h, and might be the first evidence for a mechanism by which MRT kills the whole tumour despite only a small percentage receiving peak irradiation.