Clinical implementation of a novel Double-Balloon single-entry breast brachytherapy applicator

Abstract

PurposeThe purpose of the study was to describe the clinical utilization of a novel Double-Balloon applicator for accelerated partial breast irradiation (APBI). Methods and MaterialsThe Double-Balloon single-entry breast applicator contains a single central treatment catheter, as well as four peripheral catheters that can be differentially loaded to customize radiation dose coverage. An inner balloon is filled with up to 7–30 cm3 of saline to increase separation between the peripheral catheters, and an outer balloon is filled with up to 37–115 cm3 of saline to displace breast tissue from the peripheral catheters. Treatment planning objectives include coverage of the breast planning target volume to a minimum of V90 > 90%, limiting dose heterogeneity such that V200 < 10 cm3 and V150 < 50 cm3, and limiting maximum dose to skin (<100% of prescription dose) and ribs (<145% of prescription dose). ResultsHigh-dose-rate APBI was delivered to 11 women using this device (34 Gy in 10 twice daily fractions). The mean V90 was 98.2% (range 94.2–99.4%). The mean skin Dmax with the Double-Balloon applicator was 83.3% (range 75.6–99.5%). The mean breast V200 was 5.8 cm3 (range 2.3–10.2 cm3), and the mean breast V150 was 32.9 cm3 (range 25.0–41.7 cm3). Pretreatment quality assurance was performed using CT prior to each morning fraction and ultrasound prior to each afternoon fraction. ConclusionsThe Double-Balloon applicator can be easily introduced into a previously existing brachytherapy program. APBI plans created with this applicator achieve excellent planning target volume coverage, while limiting skin dose and maintaining breast V200 < 10 cm3.