An investigation of inverse planning techniques for an experimental tomotherapy unit using a cobalt-60 source

Radiation therapy, or radiotherapy, is a commonly prescribed treatment for cancer, where ionizing radiation is used to disrupt the process of cellular reproduction in tumours. One form of radiotherapy is external beam radiation therapy, where beams of radiation are focused onto the patient from an external source. Unfortunately, for deep seated tumours, delivering a tumourcidal dose may result in excessive exposure of the normal tissue, and the patient may suffer complications. One strategy for safely escalating the tumour dose is conformal radiotherapy, where specially shaped beams deliver radiation from multiple angles around the patient. Intensity modulated radiation therapy (IMRT) takes this further, by also varying the fluence within each shaped beam. Very precise three-dimensional regions of high dose can be delivered by using computers to optimize the IMRT fluence patterns. This process is called 'inverse planning'.;Tomotherapy is a special form of IMRT where a treatment is delivered by revolving a fan beam around a patient lying on a dynamic couch. The Medical Physics group at the Cancer Centre of Southeastern Ontario has been assessing the feasibility of using a Cobalt-60 (Co-60) radiation source for tomotherapy. The goal of this thesis is the development of an inverse planning method suitable for our experimental system, so that simulations of clinically relevant treatments can be performed. (Abstract shortened by UMI.)...