Grant: Operating Grant

Cancer imposes a massive burden of suffering on Canadians each year. Radiotherapy, the therapeutic use of radiation, is one of the major and most effective cancer treatment modalities. Specifically, 50 to 60% of patients will receive radiotherapy during the course of their illness, either with a curative intent or as a palliative treatment. Radiotherapy is rarely used alone, and is involved in a complex strategy including other therapeutic modalities to decrease repopulation, metastases and thus improve survival. For each treatment in radiotherapy, hospital physicists calculate as precisely as possible the amount of radiation (i.e., dose) to be delivered to the patient and its distribution, rate and fractionation (i.e., the number of irradiation periods to deliver a given dose). These calculations, which depend on many parameters, including the type of cancer cells, their location, the other therapeutic drugs being administrated and previous surgery, must be performed from data related to the interaction of the radiation with molecules in the cells. More particularly in targeted radionuclide therapy, in order to increase considerably the benefits of this type of therapy and consequently the survival rate of patients, radiation physicists must now obtain information on the effect of the low-energy electrons generated by radionuclides at the nanoscopic scale in the cancer cells during the treatment. The main goal of our research is to provide this information by studying more specifically the probabilities of low-energy electrons to produce specific energy deposits and/or damages in biological materials. Such information can also serve in the development of new drugs that can enhance the radiosensitivity of cancer cells. The proposed research has implications not only in radiotherapy, but also on the long term effects of low dose radiation from radionuclides used for diagnostic purposes and more generally from those naturally occurring in the environment.