What is radiation therapy?

Afshin Rashtian, MD
Radiation Oncology
Afshin Rashtian, MD from Riverside Community Hospital explains what radiation therapy does and how it works. Learn more from this video.
Radiation therapy is also called radiotherapy or just radiation. It is a very effective way to destroy cancer cells. As defined by the National Cancer Institute, radiation is the use of high-energy radiation from x-rays, gamma rays, neutrons, protons and other sources to kill and shrink tumors. Radiation can be delivered in three ways:
  • External-beam radiation therapy
  • Internal radiation therapy (brachytherapy)
  • Systemic radiation therapy
Bahman A. Daneshfar, MD
Radiation Oncology

Radiation Therapy is the use of X-rays to treat cancer, benign tumors or certain benign conditions. X-rays are used to take pictures in Radiology but in Radiation Oncology they are used for treatment. X-rays are made in nature by radioactive substances or they can be man-made substances or by machines. Radiation Therapy is most commonly given by machines run by therapist and directed by the Radiation Oncologist. The treatment uses ionization to cause damage to molecules on an atomic level. In general terms the DNA of a cell is disrupted and the cell cannot grow any more. Good cells are protected by giving the radiation a little at a time so the good cells repair while the cancer cells cannot repair and eventually die. This is why usually radiation is done for a few minutes each day over many weeks (5 to 8 weeks). New methods can also be used in just a few treatments but special machines are used to fine tune the radiation precisely to the area and avoid the good tissue. Different methods are used based on what disease or strategy the Radiation doctor is using. Radiation has no feeling when you are taking it, however over the weeks taken the good tissue will have side effects that will eventually go away when treatment stops. Each part of the body will have different side effects. The Radiation team and doctor need to carefully explain all the goals and side effects for each individual patient and condition. 

John A. Chabot
Endocrinology Diabetes & Metabolism
Radiation therapy, sometimes called radiotherapy, is a technique that uses high frequency X-rays to shrink or slow the growth of cancerous tumors. Unlike chemotherapy which is a systemic treatment, radiation therapy is a local treatment meant to destroy only tumor cells. During the treatment, a beam of radiation is directed through the abdomen to the cancerous area. The radiation is similar to that used for diagnostic X-rays, only in a higher dose.

Radiation therapy (also called radiotherapy, x-ray therapy, or irradiation) is the use of a certain type of energy (called ionizing radiation) to kill cancer cells and shrink tumors. Radiation therapy injures or destroys cells in the area being treated (the "target tissue") by damaging their genetic material, making it impossible for these cells to continue to grow and divide. Although radiation damages both cancer cells and normal cells, most normal cells can recover from the effects of radiation and function properly. The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissue.

There are different types of radiation and different ways to deliver the radiation. For example, certain types of radiation can penetrate more deeply into the body than can others. In addition, some types of radiation can be very finely controlled to treat only a small area (an inch of tissue, for example) without damaging nearby tissues and organs. Other types of radiation are better for treating larger areas.

In some cases, the goal of radiation treatment is the complete destruction of an entire tumor. In other cases, the aim is to shrink a tumor and relieve symptoms. In either case, doctors plan treatment to spare as much healthy tissue as possible.

About half of all cancer patients receive some type of radiation therapy. Radiation therapy may be used alone or in combination with other cancer treatments, such as chemotherapy or surgery. In some cases, a patient may receive more than one type of radiation therapy.

This answer is based on source information from the National Cancer Institute

Continue Learning about Radiation Therapy For Cancer

Radiation Therapy For Cancer

Using ionized energy to kill cells, radiation therapy is used by half of all patients to treat cancer.Radiation kills cancer cells by damaging their genetic material beyond repair, causing them to breakdown and die. Both short- an...

d long-term side effects, such as hair and memory loss, can occur when the therapy kills healthy cells. Different types of radiation exist. When a machine outside the body delivers it, it is called external-beam radiation therapy. If radioactive materials are placed inside the body, it is called internal radiation therapy, or brachytherapy. You can also receive an injection of radioactive iodine, which travels through the body to kill cancer cells, a treatment called systemic radiation therapy. When cancer cant be cured, radiation therapy can be used to shrink tumors to make life more comfortable for a patient. Doctors may use radiation treatments alone or in combination with surgery and/or chemotherapy, which uses drugs to kill cancer cells.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.