A Radiation Dosimeter Based on Ce/Tb Co-Doped Silica Fiber for Radiotherapy Application

The increasing development of radiotherapy technology and treatment modalities has put forward new and higher requirements for dose monitoring. In this article, the Ce/Tb co-doped silica fiber was employed to implement the dose detection on a Varian EDGE linear accelerator. The stability of the system was assessed by measuring ten repeated irradiations with 6-MV X-ray beams, and the maximum percentage deviation of these exposures was 0.38%. Dose linearity was studied by measuring the accumulated optical intensity signal versus incident irradiation dose, and the experimental results indicated that the signal increases with the increasing delivered dose and exhibits apparent linear dependence on the dose (
${R}^{{2}}$
= 0.99998). The dose rate independence was also verified by the test of fixed doses with increased dose rates. Moreover, the sensor gantry rotated from 180° to 180°E, and the detected values for all the angles are almost identical with a maximum difference of 1.26%. Excellent radiation resistance has also been observed by repeated measurement with the sensor pre-irradiated at different doses. All the tests indicate that the novel sensor can meet the basic requirements for clinical dose detection. Furthermore, it provides a new way to solve some challenges in clinic dosimetry, such as the validation of small-field dosimetry and surface dose assessment.