Brachytherapy places radioactive sources internally very close to the area to be treated. Needle or balloon implants are placed in the operating room, but treatments occur on an outpatient basis. The temporary implants do not cause the patient to be radioactive and are removed after a series of twice-daily treatments.
Radiation is delivered by a high-dose-rate remote afterloading machine that allows each treatment to be given in about 10 to 20 minutes. Powerful radioactive sources travel through small tubes (catheters) to the treatment site for the amount of time prescribed by the radiation oncologist.
Internal radiation can be delivered using a number of different techniques.
- needle implant (interstitial brachytherapy) uses ultrasound and external templates to guide placement of a series of needles. After needle placement, the radiation oncologist verifies dose calculations, and the needles are connected to a high-dose treatment machine. A single radioactive seed travels through each needle to deliver the prescribed dose. Afterwards the needles are disconnected. Outpatient treatments are completed in about a week, and the implants are removed.
- balloon implant (MammoSite RTS®, balloon intracavity bracytherapy) uses an implanted balloon rather than needles to deliver radiation. The balloon is placed at the time of surgery or re-excision.