brachytherapy [Gk, brachys, short, therapeia, treatment] , the placement of radioactive sources, such as seeds, needles, or catheters, in contact with or implanted into the tumor tissues to be treated for a specific period. Sources can be temporary or permanent. The rationale for this treatment is to provide a high absorbed dose of radiation in the tumor tissues and a very limited absorbed low dose in the surrounding normal tissues. Traditional brachytherapy implants deliver low doses of radiation; the newest variations deliver high doses. Compare teletherapy.
