Experimental Validation and Calibration of Cherenkov Imaging for Real-Time Surface Dosimetry in Photon Breast Therapy.

Cherenkov imaging holds promise as a non-invasive, real-time method for surface dosimetry during photon-based external beam radiation therapy (EBRT). In this study, we evaluated the feasibility of using Cherenkov emission as a quantitative surrogate for surface dose in breast cancer treatment through Monte Carlo simulation and experimental validation. A Monte Carlo model was developed to simulate both dose deposition and corresponding Cherenkov photon emission for breast patients undergoing photon EBRT. Validation was performed using phantoms with homogeneous optical properties and varying geometries, enabling direct comparison between simulated and measured Cherenkov emission. Additionally, the simulated surface dose was validated against in-vivo measurements acquired using in-vivo dosimeters. Results show strong correlation between simulated and measured Cherenkov emission and surface dose, except at the field edges, where additional optical and geometric considerations are required. Based on these comparisons, a correction factor was derived to calibrate Cherenkov intensity to absolute surface dose. Finally, Cherenkov images acquired from breast cancer patients were compared with simulation results to assess the clinical utility of this approach. These findings support the use of Cherenkov imaging, when properly corrected, as a viable tool for real-time, patient-specific surface dosimetry in photon EBRT.