TH‐D‐352‐05: Optically Stimulated Luminescence (OSL) Dosimeters Can Be Used for Remote Dosimetry Services

Purpose: To evaluate aluminum‐oxide [formula omitted] optically stimulated luminescence (OSL) dosimeters as a potential alternative to thermoluminescent dosimeters (TLDs) for remote dosimetry services provided by the Radiological Physics Center (RPC) at the University of Texas M. D. Anderson Cancer Center. Method and Materials: OSL dosimeters were placed equidistant (< 1 cm) from the center of a 20 cm × 20 cm Solid Water™ (SW) phantom which provided backscatter and build‐up. OSL dosimeters were also irradiated in an acrylic mini‐phantom based on the RPC's mailable TLD system mini‐phantom. For modality‐dependence measurements, dosimeters were irradiated to doses of either 100 or 300 cGy with 6 or 15 MV photons or 8 or 15 MeV electrons. All other irradiations were performed with a Co‐60 unit. A Landauer microStar™ reader was used to measure the dosimeter responses. Results: The calculated percent standard deviation of the reproducibility readings was less than 1.4% for doses of 50 cGy and 300 cGy, and less than 0.9% for a dose of 1000 cGy. The measured dose response was linear at doses less than 600 cGy, and independent of modality. Field‐size output factors measured with OSL dosimeters agreed with those measured with an ion chamber within 1.5%. Heat, cold and humidity had no effect on the dosimeters, but exposure to light significantly decreased their response. Measurements of fading demonstrated that a 4% loss of signal occurs over the first ten days after irradiation, after which the response changes less than 1% up to 90 days. The dosimeters lost 0.2% of signal with each successive reading. Conclusion: The precision of OSL dosimeters is comparable to that provided by TLDs used for remote dosimetry and warrants further investigation. Conflict of Interest: This work was supported in part by Landauer Corporation and by PHS grant CA10953 from the NCI, DHHS.