Image-guided radiation therapy of cancer: Seeing what you are treating

Dr. Elsayed Ali
The Ottawa Hospital Cancer Centre

Abstract

About half of cancer patients receive radiation therapy as part of their overall cancer treatment. The radiation can be photons, electrons, protons, or carbon ions, among others. The radiation source can be external (e.g., from a clinical linear accelerator) or internal (e.g., from an implanted radioactive source). Sophisticated optimization algorithms are used to create digital treatment plans that maximize the radiation dose deposited in the cancer target while minimizing the radiation dose to the surrounding healthy tissues as much as reasonably achievable. The success of a radiation treatment strongly depends on accurately delivering the treatment as planned, with minimal geometric and dosimetric deviations. A large array of image guidance and patient positioning systems have been developed to enable accurate radiation treatment delivery. In this talk, I will give an overview of these systems and the role of the clinical medical physicist in the development and implementation of such systems, with examples from the research work done at The Ottawa Hospital Cancer Centre. In the last part of my talk, I will highlight the exciting new developments in image guidance, which are expected to cause a paradigm shift in how radiation therapy of cancer is delivered in the near future.