Radiation therapy is a treatment for cancer and other diseases. It uses high-energy particles to damage the genetic code (DNA) in the cancer cells. This makes the cells unable to grow or divide.
There are two main types of radiation therapy:
- External—radiation is delivered by a machine that shoots particles at the cells from outside the body
- Internal —radioactive materials are placed in the body near the cancer cells (also called implant radiation or brachytherapy)
In certain cases, your doctor may recommend a combination of these. Radiation is often used with other types of treatment, such as surgery, chemotherapy, and immunotherapy (stimulates the immune system to fight infection).
This fact sheet will focus on external radiation therapy.
Last reviewedSeptember 2012by Igor Puzanov, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.