A registry trial has been designed and modeled after the original successful TARGIT protocol, to continue the use of IORT for a select population of women, and to follow outcomes with regards to local and regional control, toxicity and morbidity. Patients selected for breast conserving surgery, who are considered to have a low risk of local recurrence, are eligible for this registry trial once their informed consent is obtained. This single arm cohort study allows entry of patients who have been diagnosed with early stage breast cancer and whose clinical stage is suitable for treating conservatively (small tumor and no gross nodal involvement). Tumors should not be more than 3.5 cm in size.