Abstract
Background: Accurate quantification of surface dose is critical in radiation therapy, particularly for patients with breast cancer, for whom the risk of cutaneous toxicity is substantial. In this study, we evaluated the clinical feasibility of a novel flexible radiochromic film specifically designed to improve adhesion and usability on curved anatomic surfaces.Materials and Methods: The study prospectively enrolled 20 patients with breast cancer undergoing volumetric modulated arc therapy. Surface dose was measured using flexible radiochromic film placed near the surgical scar and close to the isocenter. Calibration curves were established using a 6 MV photon beam with flattening filter free and without, and the film response was analyzed in both transmission and reflection scanning modes. The measured surface doses were then compared with those calculated by the treatment planning system (TPS).Results and Discussion: The flexible radiochromic film demonstrated excellent sensitivity in the 1.5–2.5 Gy dose range, with superior performance observed in the transmission scanning mode. The film adhered securely to skin without requiring additional fixation and was removed without causing discomfort to the patient. Notably, substantial discrepancies were found between the measured and TPS-calculated surface doses, underscoring the limitations of a TPS in accurately modeling skin dose.Conclusion: Flexible radiochromic film demonstrated dosimetric performance similar to that of conventional films while offering enhanced flexibility and ease of clinical use. Given the significant uncertainty in TPS-based surface-dose estimation, the film provides accurate and practical in vivo surface-dose assessment in breast cancer radiotherapy.