Radiation Therapy

What is Radiation Therapy and How Does it Work?

Radiation therapy is a cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors.  Radiation is energy that’s carried by waves or a stream of particles and it works by damaging the genes (DNA) in cells. Genes control how cells grow and divide, and when radiation damages the genes of cancer cells, they cannot grow and divide any more. Over time, the cancer cells die. Radiation therapy is one of the most common treatments for cancer and it may be used to shrink early-stage cancer, stop cancer from coming back, or to treat symptoms when cancer has spread.

Radiation therapy is broadly divided into External Beam Radiation Therapy (EBRT), where radiation is delivered to the target from an external machine, and Brachytherapy, where radiation is delivered by placing the radiation source inside the body near the intended target. EBRT delivers radiation to the target site from an external machine, typically called a linear accelerator, or LINAC. The LINAC generates high-energy X-ray beams and is equipped with an imaging system that precisely targets the tumor while delivering radiation, destroying cancer cells and minimizing exposure to surrounding healthy tissue.

When designing your treatment plan, your medical team relies on one or more types of 3-D scans of your body. These can include a CT scan, an MRI and/or a PET scan. By looking at these scans and other test results, the radiation oncologist and his or her team determine which radiation therapy technique is best suited for your particular case.