What Are Seed Implants?

Prostate seed implants fall under the category of brachytherapy, a form of radiation treatment in which radioactive materials are placed directly into a cancer-affected organ with the intent of destroying the malignancy. Brachytherapy may be thought of as internal radiation in contrast to the more traditional external beam treatment in which radiation is directed through the body area from an outside source.

Seed implant treatment refers to the placement of tiny radioactive pellets, or seeds, directly into the prostate using needles guided by some type of medical imaging usually ultrasound. The seeds are about the size of a grain of rice (top). Rows of seeds are deposited uniformly throughout the prostate so that the radiation can cover the entire gland (bottom).

Depending on the radioactive material used (Iodine125, Palladium103 or Cs-131), the seeds release radiation gradually over a period of 6 to 12 months after which they become completely inert. Since they lose all of their radioactivity, the seeds do not have to be removed and can safely remain in the prostate for the rest of the patients life.