Women who have undergone a lumpectomy (but not a mastectomy) may undergo external radiation for several weeks, followed by a boost of radiation to the tumor bed. Although this boost is usually given with an electron beam, selected cases are offered the alternative of a radioactive implant to provide the boost.

The implant is more invasive, but can allow for less skin reactions when patients with very deep tumors require treatment. The hollow catheters via which the radioactive seeds are placed are inserted into the breast tissue under general anesthesia, and are left in place from two-five days, as needed. The tubes are subsequently removed in the office with minimal discomfort at the end of treatment.

A new procedure called Mammosite is being evaluated to see if it can replace the usual course outlined above with a simple implant in the lumpectomy cavity all treated over one week, in selected patients.