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Professor Emeritus, Department of Oncology , University of Western Ontario
Adjunct Professor, Department of Physics and Astronomy , University of Western Ontario
Manager, Clinical Physics , London Regional Cancer Program
Outcome Optimization in 3-Dimensional Conformal Radiation Therapy
This research is aimed at developing a computational model, which will account for all of the uncertainties associated with the use of sophisticated 3-D CRT techniques. Our analysis includes the quantitative assessment of uncertainties associated with every stage of the radiation therapy process, to propagate these uncertainties, and to predict outcome both in terms of final dose delivery and expected patient response. A thorough understanding of uncertainties in each step of the treatment process will: (1) aid the radiation oncologist in clinical decision making for optimal (and cost-effective) use of new 3-D CRT technology, (2) provide relevant input information into designing clinical trials to yield meaningful results, and (3) provide guidance for future research directions in radiation oncology focusing on the weak links in the overall treatment process. The ultimate benefit is to improve cancer control and reduce side effects for the many patients undergoing radiation treatments.
Prediction of Biological Response in Lung Tissue
We have performed (at the Ontario Cancer Institute, Toronto) a major rat experiment to assess various isoeffect formulae which account for tissue fractionation parameters. Present experiments involve the evaluation of the calculation models for partial volume lung irradiation. Measurement endpoints include breathing rates and genotoxic damage using micronuclear counting techniques in rat lung fibroblasts. The latter assay is being used to evaluate effects both inside and outside of the irradiated tissues within the lung. This is the first use of this assay in the context of partial volume lung irradiation. Further experiments are planned to understand the mechanisms associated with in-field and out-of-field effects and also to derive partial volume parameters using both lethality and breathing rates as evaluation endpoints. These will allow for the assessment of the accuracy of existing biological models and for the modification of such models as needed. The animal experiments are being carried out in Toronto in collaboration with Drs. Mohammed Khan and Richard P. Hill.
|Figure 1. (a) Normal cell division shows as a binucleated cell under a microscope.||Figure 1. (b) A binucleated cell with multiple micronuclei as a result of DNA damage in lung fibroblasts due to irradiation.|