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A cancer patient and her oncologist discuss the next steps in her treatment plan.

Radiation Therapy

Radiation therapy uses ionizing radiation to injure or destroy targeted cells, usually cancer cells, while preserving as many normal surrounding cells as possible. Radiation therapy may be used to reduce the size of a cancer before surgery, to destroy any remaining cancer cells after surgery, or, in some cases, as the main treatment. It can also be used in conjunction with chemotherapy. Dependent on your type of cancer and other factors, your physician may choose to use either external beam radiation therapy or internal radiation therapy.

External beam radiation therapy is the most frequently used type of radiation for cancer patients. During this process, a radiation oncologist will use a machine to aim high-energy beams of radiation from outside the body toward the tumor.

Internal radiation therapy, also called brachytherapy, uses a radiation source that’s usually sealed in a small implant. This implant is placed into the body near or inside the tumor, targeting the therapy to harm as few healthy cells as possible.

Gamma Knife

Gamma Knife is a technique that uses targeted radiation to treat brain tumors and other neurological conditions. This procedure does not involve any incisions. Rather, surgeons direct highly targeted beams of radiation to areas of the brain that require treatment, eliminating the risk of damaging surrounding healthy tissue. Learn more.


A non-invasive alternative to surgery for cancerous and non-cancerous tumors, CyberKnife® tracks, detects, and corrects for motion to administer precise radiation dose therapy. CyberKnife® is used to treat many tumors and lesions that may have been previously considered inoperable or untreatable. Learn more.


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