Abstract

Title: High-precision dosimetry for radiotherapy using the Optically Stimulated Luminescence (OSL) technique and thin Al₂O₃:C dosimeters.

Authors: Eduardo G. Yukihara¹, Elisabeth M. Yoshimura^1,3, Timothy D. Lindstrom¹, Salahuddin Ahmad², Kristen K. Taylor², George Mardirossian².

¹ Department of Physics, Oklahoma State University, Stillwater, OK 74078.

² Department of Radiation Oncology, University of Oklahoma Health Sciences Center, 825 N.E. 10th Street, OUPB 1430, Oklahoma City, OK 73104.

The potential of using the Optically Stimulated Luminescence (OSL) technique with aluminum oxide (Al2O3:C) dosimeters for precise and accurate estimation of absorbed doses delivered by high-energy photon beams was investigated. This study demonstrates the high reproducibility of the OSL measurements and presents determination of the depth dose curve in water for 6 MV and 18 MV photon beams, and 6 to 20 MeV electron beams from a linear accelerator. The uncertainty of a single OSL measurement, estimated from the variance of a large sample of dosimeters irradiated with the same dose, was 0.69%. The readout procedure includes a normalization of the response of the dosimeter with respect to a reference dose in order to eliminate variations in the dosimeter mass, dosimeter sensitivity, and reader sensitivity. This may be relevant for quality assurance programs, since it simplifies the requirements in terms of personnel training to achieve the precision and accuracy necessary for radiotherapy applications. Preliminary laboratory results using Al2O3:C powder are also presented.