Encapsulated configuration of a flexible transparent adhesive bolus to improve surface conformity and skin safety in post-mastectomy radiation therapy.

This study evaluates the clinical feasibility and surface conformity of ClearFit2-Encapsulated, a technical configuration implemented to facilitate the clinical use of highly adhesive transparent boluses through a film-dressing encapsulation method for post-mastectomy radiation therapy (PMRT). ClearFit2 was encapsulated with a thin polyurethane film. Following benchmark phantom comparisons of three bolus configurations (ClearFit1, ClearFit2, and ClearFit2-Encapsulated) using planning CT, clinical performance was evaluated in eight PMRT patients using weekly cone-beam CT (CBCT) to quantify air-gap distances. In phantom evaluation, mean gaps were 3.9 ± 3.1 mm for ClearFit1, 0.9 ± 0.9 mm for ClearFit2, and 2.2 ± 2.2 mm for ClearFit2-Encapsulated. In clinical evaluation, the median air-gap distance across all cases was 1.1 mm (range: 0.6-1.7 mm), with 88.2% of the interface area maintaining gaps ≤ 3 mm. ClearFit2-Encapsulated demonstrates high surface conformity and clinical feasibility, providing a practical bolus-handling solution for patients undergoing PMRT.