Optimization of Dose Distribution

Abstract

Radiotherapy, if used appropriately, constitutes a very effective treatment for cancer. It is considered as the second, after surgery, most effective type of cancer treatment. In developed countries more than half of all cancer patients are treated with ionizing radiation. Radiation therapy is used both for radical and palliative treatment. The radiation affects only the tissues in the treated area and not the rest of the body. Therefore, it is known as a local method of treatment. Radiotherapy, like any other form of treatment, has risks and benefits. The risks are associated with the dose delivered to normal organs and tissues. Therefore, every application of radiation for the treatment of patients suffering from cancer has to be optimized. The goal of radiotherapy is to deposit the prescribed dose in a cancer tumour while minimizing the dose that reaches the surrounding normal tissue. To achieve this aim, the spatial dose distribution should conform to the target volume, and the gradient of the dose distribution outside of the target should be as high as possible – the dose should quickly falls off.