High-dose radiation

Fact Sheet from Memorial Hermann
High-dose radiation
Sept. 26, 2005

Radiation prescribed to treat cancer can be delivered externally or internally. Internal methods can provide higher doses of radiation at or near the cancer site. They can be used alone or in conjunction with external - beam radiation.
Low-dose forms of internal radiation sometimes involve implanting radioactive seeds that remain in the body permanently but lose their potency after a few weeks. In other cases, patients must stay in the hospital for a few days and remain immobile while the radiation source is in the body.
Newer, high-dose radiation (HDR) available at Memorial Hermann hospitals reduces treatment time and can be provided on an outpatient basis.
With HDR, a treatment device or holder is placed in the body. A machine called an afterloader houses a radioactive source. During treatment, the source is extended through a catheter, or tube, to deliver radiation to the cancer site for five to 10 minutes. Patients typically receive two to five treatments over the course of a week.
“You're getting a very high, focused radiation dose very rapidly, which increases the likelihood of eradicating the cancer,” explained Kirk Kanady, M.D ., medical director of the Cancer Center at Memorial Hermann The Woodlands Hospital.
HDR can be used to treat a wide variety of malignancies including prostate tumors as well as head, neck, lung, bowel and cervical cancers.
At Memorial Hermann The Woodlands Hospital, radiation oncologists will most often use the Cancer Center 's new HDR capabilities to treat breast cancer, Dr. Kanady said . For appropriately selected patients, HDR treatments may allow for the preservation of the breast without requiring the five to six weeks of standard radiation therapy.
With breast cancer patients, a balloon catheter is inserted in the cavity created by lump removal. The HDR device delivers radiation into the saline-filled balloon, which is removed when treatments are complete.

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