gamma knife


Brachytherapy is a type of internal radiation treatment. With this method, radioactive sources (or “seeds”) are implanted either within or immediately next to tumor tissue.

The radiation will primarily affect tissue near each radioactive seed, so that tissue further from the seeds receives increasingly lower doses of radiation. This technique limits radiation exposure to a localized area around the radiation sources, minimizing exposure of healthy tissues away from the tumor.

In the case of brain tumors, brachytherapy is performed using a low dose rate (LDR) technique with Cesium-131 sources. Brachytherapy utilizes a lower dose of radiation, since the radioactive seeds are permanently implanted at the tumor site. Brachytherapy is typically performed on newly diagnosed large brain metastases not amenable to radiosurgery, recurrent brain metastases, and recurrent atypical and malignant meningiomas. During the operation, the neurosurgeon and radiation oncologist will work together to carefully position the radioactive seeds. The seeds are placed permanently, but over time, will give off less radiation.

Brachytherapy can be provided alone or in combination with other therapies, such as surgery, external beam radiation, or chemotherapy. Most patients are able to tolerate the procedure very well, and the treatment is associated with a low risk of serious side effects. Brain tumors that may be considered for brachytherapy include the following:


This content was reviewed by UCSF radiation oncologist David Raleigh MD, PhD.