Array of square waveguides for scintillation dosimetry in external radiotherapy

Abstract

An array of air core scintillation dosimeters (of round or square cross section) is an efficient solution for managing the problem of Cerenkov background light in megavoltage radiation. This array generates a high-resolution dose map in a way that satisfies ICRU dosimetric accuracy recommendations without the need for correction factors. Efficient scintillation signal transportation is vital to sensitivity of the dosimeter. The attenuation of the light irradiance as a function of waveguide length in PMMA and silver hollow square and round waveguides is studied experimentally and theoretically. In practice, the silvered square waveguide has the least attenuation while the PMMA square waveguide performs almost as well as commercially sourced silvered tubes. The attenuation of the commercially sourced tubes is increased by the rough internal silver surfaces.