Brachytherapy, also call internal radiation, involves placing radioactive material close to or inside the cancer. A higher dose of radiation can be given to a smaller area of the body compared with external radiation treatments. By minimizing the radiation given to surrounding normal tissues, side effects are reduced.
A seed implant or prostate brachytherapy, involves placing radioactive seeds, about the size of a grain of rice, in the prostate and leaving them there permanently. Over several months, the radiation in the seeds diminishes to nothing. The seeds then remain in the body, with no lasting effect.
Seed implants are done in an operating room under a general anesthetic as an outpatient procedure. Ultrasound is used to assist the physician in positioning needles in the prostate. These needles are preloaded with the radioactive seeds. The needles are removed, leaving the seeds behind. A CT scan will be done one month after the implant to verify seed placement.
Initially after the implant, it is common to experience mild to moderate discomfort with urination as well as more frequent urination. These symptoms go away within a few days to several weeks.
Other possible side effects include impotence, which occurs less often than in patients who undergo surgery or external radiation therapy. There is also a risk of bladder or rectal problems, which may cause frequent urination, urgent urination, diarrhea or rectal bleeding. These symptoms can occur one to three years after the implant. Simple interventions, such as diet changes and medications, are sometimes required.