- Intracavitary balloon brachytherapy boost and AWBI (post-lumpectomy): Patients undergo intracavitary balloon brachytherapy boost twice daily for 2 days (total of 4 fractions). Beginning 5-21 days after completion of brachytherapy, patients undergo AWBI once daily 5 days a week for approximately 2 weeks (total of 11 fractions).