Performance characteristics of a gated fiber-optic-coupled dosimeter in high-energy pulsed photon radiation dosimetry

Fiber-optic-coupled dosimeters (FOCDs) are a new class of in vivo dosimetry systems that are finding increased clinical applications. Utility of FOCDs has been limited in dosimetric applications due Cerenkov-ray signal contamination. The current study reports on the characterization of a novel FOCD, with a gated detection system for the discrimination and effective elimination of the direct contribution of Cerenkov radiation, for use in the radiotherapeutic realm. System reproducibility, linearity and output dependence on dose rate, energy, field size, and temperature response were characterized for 6, 10, and 15 MV photon energies. The system exhibited a linear response to absorbed dose ranging from 1 to 2400 cGy and showed little dependence to dose rate variations. Overall system reproducibility was 0.52% with no field-geometry and temperature dependence.