Purpose: To extend the lifetime use of Optically Stimulated Luminescent Dosimeters (OSLDs) above the 10 Gy limit defined by TG-191 for use at the Imaging and Radiation Oncology Core- Houston.
Methods: 100 nanoDot OSLDs were irradiated in 4 Gy intervals up to 30 Gy to investigate performance changes with sensitivity and linearity as cumulative dose was increased. Initial characterization of average sensitivity, element sensitivity, and linearity (up to 3 Gy) was done. The detectors were bleached after each irradiation. Changes in ksi were determined by taking the percent difference between ksi at each dose interval relative to their initial commissioned ksi. Changes in the mean were evaluated with an Anova test while consistency was determined by a Levene test.
Results: The average sensitivity was consistent within 1.59% of the mean from 0-27 Gy and dropped by 4.21% at 30 Gy which was statistically significant (p < 0.05). The coefficient of variation did not significantly increase. ksi was consistent within +/- 2%, 90% of the time. Comparing kL from 0-30 Gy using a linear regression we found that they were statistically significantly different (p < 0.05) with a maximal dose difference of 5.53% at 3 Gy. the Variance in sensitivity and kL did not change from 0-30 Gy.
Conclusion: OLDS are capable of being used up to 30 Gy for use at IROC-Houston. Sensitivity needs to be accounted for which can be done through a session specific calibration coefficient which is normal operation at IROC.
Calibration, Dose Response, Dosimetry Protocols