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SU‐E‐T‐592: OSL Response of Al2O3:C Detectors Exposed to Therapeutic Proton Beams
Author(s) -
Granville DA,
Flint DB,
Sawakuchi GO
Publication year - 2015
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4924955
Subject(s) - optically stimulated luminescence , dosimeter , materials science , absorbed dose , optics , dosimetry , beam (structure) , proton , irradiation , nanodot , nuclear medicine , physics , radiation , optoelectronics , luminescence , nuclear physics , medicine
Purpose: To characterize the response of Al 2 O 3 :C optically stimulated luminescence (OSL) detectors (OSLDs) exposed to therapeutic proton beams of differing beam quality. Methods: We prepared Al 2 O 3 :C OSLDs from the same material as commercially available nanoDot dosimeters (Landauer, Inc). We irradiated the OSLDs in modulated proton beams of varying quality, as defined by the residual range. An absorbed dose to water of 0.2 Gy was delivered to all OSLDs with the residual range values varying from 0.5 to 23.5 cm (average LET in water from ∼0.5 to 2.5 keV/µm). To investigate the beam quality dependence of different emission bands within the OSL spectrum, we performed OSLD readouts using both continuous‐wave stimulation (CW‐OSL) and pulsed stimulation (P‐OSL) with two sets of optical filters (Hoya U‐340 and Kopp 5113). For all readout modes, the relative absorbed dose sensitivity (S rel ) for each beam quality was calculated using OSLDs irradiated in a 6 MV photon beam as a reference. Results: We found that the relative absorbed dose sensitivity was highly dependent on both readout mode and integration time of the OSL signal. For CW‐OSL signals containing only the blue emission band, S rel was between 0.85 and 0.94 for 1 s readouts and between 0.82 and 0.93 for 10 s readouts. Similarly, for P‐OSL readouts containing only the blue emission band S rel ranged from 0.86 to 0.91, and 0.82 to 0.93 for 1 s and 10 s readouts, respectively. For OSLD signals containing only the UV emission band, S rel ranged from 1.00 to 1.46, and 0.97 to 1.30 for P‐OSL readouts of 1 s and 10 s, respectively. Conclusion: For measurements of absorbed dose using Al 2 O 3 :C OSLDs in therapeutic proton beams, dependence on beam quality was smallest for readout protocols that selected the blue emission band with small integration times. DA Granville received financial support from the Natural Sciences and Engineering Research Council of Canada