Abstract

Cancer radiotherapy is planned with the aim of delivering a lethal dose of radiation to a tumour, while keeping doses to nearby healthy organs at an acceptable level. Organ movements and shape changes, over a course of treatment typically lasting four to eight weeks, can result in delivered doses being different from planned. The VoxTox project aims to measure delivered dose, at the level of millimetre-scale volume elements (voxels), and to correlate with short- and long-term side effects (toxicity). The techniques developed may be used for dose monitoring in a clinical setting, and allow improved treatment strategies.

Measuring delivered dose in radiothearpy treatment is the problem of understanding energy depositions by X-rays in a human calorimeter. The latter is characterised by complicated geometries, inhomogeneities in construction materials, and severe alignment difficulties. This seminar outlines progress in the VoxTox project in measuring doses to organs at risk of damage during treatment for prostate cancer, and for cancers of the head and neck.