Purpose: The purpose of the study was to describe the clinical utilization of a novel Double-Balloon applicator for accelerated partial breast irradiation (APBI).
Methods and materials: The 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).
Results: High-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.
Conclusions: The 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.
Keywords: Accelerated partial breast irradiation; Brachytherapy; Breast cancer.
Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.