So-Yeon Park1, Chang Heon Choi1, Jong Min Park2, Minsoo Chun1, Ji Hye Han3, Jung-In Kim4. 1. Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea; Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. 2. Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea; Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea; Center for Convergence Research on Robotics, Advance Institutes of Convergence Technology, Suwon, Republic of Korea. 3. Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea; Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. 4. Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea; Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: madangin@gmail.com.
Abstract
PURPOSE: We aimed to evaluate the characteristics of optically stimulated luminescence dosimeters (OSLDs) with fully filled deep electron/hole traps, and determine the optimal bleaching conditions for these OSLDs to minimize the changes in dose sensitivity or linearity according to the accumulated dose. METHODS: InLight nanoDots were used as OSLDs. The OSLDs were first pre-irradiated at a dose greater than 5kGy to fill the deep electron and hole traps, and then bleached (OSLDfull). OSLDfull characteristics were investigated in terms of the full bleaching, fading, regeneration of luminescence, dose linearity, and dose sensitivity with various bleaching conditions. For comparison, OSLDs with un-filled deep electron/hole traps (OSLDempty) were investigated in the same manner. RESULTS: The fading for OSLDfull exhibited stable signals after 10min, for 1 and 10Gy. The mean supra-linear index values for OSLDfull were 1.001±0.001 for doses from 2 to 10Gy. Small variations in dose sensitivity were obtained for OSLDfull within standard deviations of 0.85% and 0.71%, whereas those of OSLDempty decreased by 2.3% and 4.2% per 10Gy for unfiltered and filtered bleaching devices, respectively. CONCLUSIONS: Under the bleaching conditions determined in this study, clinical dosimetry with OSLDfull is highly stable, minimizing the changes in dose sensitivity or linearity for the clinical dose.
PURPOSE: We aimed to evaluate the characteristics of optically stimulated luminescence dosimeters (OSLDs) with fully filled deep electron/hole traps, and determine the optimal bleaching conditions for these OSLDs to minimize the changes in dose sensitivity or linearity according to the accumulated dose. METHODS: InLight nanoDots were used as OSLDs. The OSLDs were first pre-irradiated at a dose greater than 5kGy to fill the deep electron and hole traps, and then bleached (OSLDfull). OSLDfull characteristics were investigated in terms of the full bleaching, fading, regeneration of luminescence, dose linearity, and dose sensitivity with various bleaching conditions. For comparison, OSLDs with un-filled deep electron/hole traps (OSLDempty) were investigated in the same manner. RESULTS: The fading for OSLDfull exhibited stable signals after 10min, for 1 and 10Gy. The mean supra-linear index values for OSLDfull were 1.001±0.001 for doses from 2 to 10Gy. Small variations in dose sensitivity were obtained for OSLDfull within standard deviations of 0.85% and 0.71%, whereas those of OSLDempty decreased by 2.3% and 4.2% per 10Gy for unfiltered and filtered bleaching devices, respectively. CONCLUSIONS: Under the bleaching conditions determined in this study, clinical dosimetry with OSLDfull is highly stable, minimizing the changes in dose sensitivity or linearity for the clinical dose.