Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023)

Radiation therapy seeks to destroy cancerous cells by delivering a lethal dose of ionizing radiation to the tumour while minimizing the irradiation of surrounding healthy tissue. A typical radiation treatment regimen is delivered over a period of weeks in a series of daily treatment fractions. One important area in which current radiation therapy techniques are not optimal is that they do not account for the changes in anatomy during therapy. Specifically, internal anatomy will move and deform during treatment delivery due to physiological processes such as respiration and digestion. Tumours shrink and the configuration of the surrounding tissue can change from one treatment fraction to the next. Treatment plans which do not account for these changes may not achieve an optimum balance between tumour control and sparing healthy tissue.

To solve this problem, adaptive radiation therapy techniques are currently being investigated to compensate for the anatomical changes which occur over the course of a radiation treatment. However, there are a number of technical and scientific challenges which must be solved before routine clinical use of adaptive radiation therapy. One of these challenges is that an accurate determination of the radiation dose delivered to the tumour and surrounding tissues is required to guide the treatment adaptation. This dose calculation should account for tissue motion during beam delivery, tissue shrinkage and/or expansion between treatment fractions, as well as any machine-related errors in the treatment delivery.

This research program will address this challenge by developing a framework of software and verification tools for reconstruction of delivered dose accounting for anatomical changes during a radiotherapy treatment course. The research will build upon the capabilities of a novel dose reconstruction method developed under a previously-funded NSERC DG research program. The specific objectives are to develop: (1) methods to accurately model internal organ motion; (2) novel deformable phantoms and dosimeters for validation of motion modelling and dose reconstruction; and (3) methods to estimate cumulative dose, over multiple treatment fractions, accounting for tumour shrinkage and normal tissue changes. The applicant is a recognized leader in the development of the accurate dose accumulation methods which will be used in this program.

The proposed research will provide key technical tools which will permit verification of patient dose delivery over a radiotherapy treatment course. These technical innovations will inform the need for, development of, and verification of current and future adaptive treatment strategies. This will ultimately improve the effectiveness of radiation therapy to treat cancer.