SEER Logo

SEER Training Modules

Review: Radiation Therapy

Two major types of radiation therapy are external beam radiation therapy and internal radiation therapy. External beam radiation therapy delivers radiation from a source at a distance from the body and is directed at the cancer site. Internal radiation therapy places radiation sources as close as possible to the tumor site. There are several sub-categories of internal radiation therapies based on the way radiation is placed inside the body: interstitial, intracavitary, intraluminal, and intravenously.

Radiation therapy is often used when surgery is impossible or part or all of an organ would be removed if curative surgery were performed. Radiation therapy is most effective on radiosensitive cells.

As an adjuvant therapy, radiation therapy is used to destroy microscopic cancer cells before and after other therapies. Lower doses of radiation are given to cancer patients for palliative purposes, most often given to bony metastases.

Common side effects of radiation therapy are fatigue, nausea, hair loss, and depression.

Quiz

Go to the quiz if you want to test yourself on the material you learned in this section. The quiz is a self-assessment tool and no records are kept. The feedback will let you know if you have answered the questions correctly. You can take the quiz as many times as you want.

Click here to take the quiz.