Grant: Doctoral: Vanier Canada Graduate Scholarships

Microbeam radiation therapy (MRT) is a novel form of radiation therapy (RT) using synchrotron x-rays and a special collimator capable of producing microscopic slits of high dose radiation that are separated by larger spaces with little dose delivered. Unexpectedly, some animal studies have shown that MRT damages tumor tissue to a greater extent than normal tissue, which implies that an investigation into MRT could improve treatments of human cancer. It has been suggested in several studies that MRT may be useful in treating malignant brain tumors in young children without the long-term neurological deficits common with conventional RT treatments. In adults, MRT may be beneficial for shallow tumors with relatively superficial sensitive healthy structures nearby. However, the tolerance of normal tissues to MRT is not yet well understood; such understanding requires a reliable method of quantifying the dose deposited. The objective of my research is to develop accurate dosimetry for animal MRT experiments at the Canadian Light Source (CLS) so their results will have the greatest applicability to human treatments. My current research uses computer simulations to verify MRT doses measured in geometrically simple phantoms. The proposed research will build upon this foundation to develop a protocol for use of computer simulations to calculate doses for non-trivial geometries, specifically for animal experiments at the CLS. Simulation results will be verified with measurements using several dosimeters. Using the developed dosimetric system, the tolerance of the eye to MRT will be estimated. A secondary objective of my Ph.D will be development of better methods of assessing the biophysical damage caused by MRT and understanding the differential response of MRT in normal versus tumor tissue. The improvement in biophysical dosimetry for MRT experiments at the CLS will result in an advancement in Canada's role in the use of synchrotron radiation in treating disease.