Simulating Cherenkov radiation generated by radiotherapy beams

Abstract

Cherenkov radiation has had various applications in high-energy physics since its discovery, and this research explores two applications of Cherenkov radiation relating to its presence in media under irradiation by medical radiotherapy beams. In real-time organic scintillating fiber dosimeters, the radiation fluence passing through the scintillating fibers produces Cherenkov light noise in addition to the scintillation light signal. Quantifying the Cherenkov light through Monte Carlo simulations allows us to optimize various parameters of the device, such as the spectral sensitivity profile of the photodetector attached to the end of the fiber and the fiber's shape, thickness, and emission spectrum, which allows full characterization of the Cherenkov noise in the scintillation-based detector. A second application attempts to directly measure the irradiation of surface cutaneous tissue by imaging the Cherenkov light emitted from the skin surface. The optical properties of the Cherenkov emission depend on the concentration of molecular absorbers in the epidermal and dermal layers of the skin, the optical scatter in the epidermis, and the distribution of high-energy electrons propagating through the cutaneous tissue, and the Cherenkov signal carries information on erythema development and the treatment response.