Radiation and radioactivity were discovered over 100 years ago. Since then doctors have looked at ways to use radiation to treat cancer. Advances in technology and a better understanding of its effects on the body have made radiation therapy an important part of cancer treatment today. In fact, about half of all people with cancer will get radiation as at least part of their cancer treatment.

Here we will help you understand what radiation therapy is, how it is used to treat cancer, and what some of the common side effects are. For more detailed information on the possible side effects of radiation and how to deal with them, please see our document, Understanding Radiation Therapy: A Guide for Patients and Families.