Several accelerated partial breast irradiation techniques have been reported including external beam conformal irradiation, intra-operative radiotherapy and brachytherapy techniques. Brachytherapy has been the most widely evaluated accelerated partial breast irradiation technique. It involves the insertion of radioactive material directly into the surgical cavity using tubes or catheters. Treatments are generally delivered as an outpatient procedure using high dose rate (HDR) brachytherapy, delivering multiple treatments (8 to 10) over a period of 5 to 8 days. Intra-operative radiotherapy is delivered in a single session at the time of initial surgery.