What Is Radiation Oncology?

Medically Reviewed by Melinda Ratini, MS, DO on August 30, 2022
3 min read

If you have cancer, you might see a doctor who specializes in radiation oncology. It's an area of medicine that uses "radiation therapy" -- a treatment that focuses high-energy waves on your body to kill cancer cells.

Your doctor will decide if it's right for you based on the type and stage of your cancer, plus other health conditions you have.

Many doctors and health experts are part of a cancer care team. For radiation therapy, your main doctor is a radiation oncologist. They specialize in radiation oncology and lead a group of medical professionals that can include:

Radiation therapy nurse. A registered nurse who can help educate you about treatment. They can also help you manage side effects.

Radiation therapist. A person trained to work the devices that give radiation therapy.

Dosimetrist. Someone who arranges the right dose of radiation therapy for you.

Medical physicist: A person who uses their physics knowledge for radiation treatments, devices, and technology. They may help plan your radiation therapy and make sure the equipment is safe and works right.

Radiation therapy damages the genetic material of cancer cells to kill them or slow their growth. More than half of people with cancer get it.

Your doctor may suggest one of these types of radiation therapy:

External beam radiation therapy. A machine outside your body aims radiation where your cancer is. The device can move around you to point the radiation at a precise part of your body from different directions. It won't touch you.

You get external beam radiation therapy at a hospital or treatment center over many weeks. It doesn't make you radioactive, so it's safe for people to be around you.

Internal radiation therapy. Your doctor puts a solid or liquid radiation source inside your body.

Your doctor may suggest a type of internal radiation therapy called "brachytherapy." In this procedure, the radiation source is in a capsule or other implant item. Doctors often use an applicator or a slim, stretchy catheter tube to put the implant in or near your cancer. The radiation source may stay inside your body for just a few minutes, several days, or longer.

You may also hear your doctor talk about another kind of internal radiation therapy called "systemic radiation." You take liquid radiation through your mouth or a vein. The radiation moves through your body to find and destroy cancer cells.

Internal radiation therapy might make your body give off radiation. You may have to follow safety guidelines, depending on your dose.

External beam radiation therapy can treat many cancers, including breast, colorectal, esophageal, head, neck, lung, and prostate cancer.

Brachytherapy is used for some of the same cancers that external beam radiation therapy can treat. Examples are head, neck, breast, and prostate cancers. Brachytherapy often also works for cervix and eye cancers.

A type of systemic radiation therapy called radioactive iodine (I-131) can treat some thyroid cancers.

Targeted radionuclide therapy, another type of systemic radiation therapy, can treat advanced prostate cancer or gastroenteropancreatic neuroendocrine tumors (GEP-NETs).

You may only get radiation therapy to treat your cancer. Or your doctor may combine it with surgery, chemotherapy, or immunotherapy.

Sometimes your doctor can give you radiation therapy before surgery to make your tumor smaller. You could also have it after surgery to stop the cancer from coming back.

Sometimes, radiation therapy happens before chemotherapy. Other times, it's combined with chemo.

Your doctor may give you cancer medication and radiation together to make them both work better, depending on your type of cancer. If you have advanced cancer, your doctor may suggest radiation therapy to ease pain or help with problems like trouble breathing or swallowing, or in situations where your child has a blockage in their bowels.