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Quantification of Signal Strength Variation Between OSLD Drawers

K Rasmussen

K Rasmussen1*, J Roring2 , N Astorga3 , R George4 , D Stanley5 , S Stathakis6 , D Saenz7 , A Gutierrez8 , N Papanikolaou9 , (1) University of Texas HSC SA, San Antonio, TX, (2) ,San Antonio, TX, (3) ,San Antonio, TX, (4) ,San Antonio, TX, (5) UTHSCSA, San Antonio , TX, (6) Cancer Therapy and Research Center, San Antonio, TX, (7) University of Texas HSC SA, San Antonio, TX, (8) Miami Cancer Institute , Miami, FL, (9) University of Texas HSC SA, San Antonio, TX


SU-I-GPD-T-310 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: Landauer recently released a redesigned drawer for the microstarii OSLD reader to allow for increased signal read strength of current OSLD nanoDots. This work evaluates the relative signal increase of this drawer.

Methods: A Varian 2300 with energies of 6MV photons and 9MeV electrons were used to expose OSLDs to doses of 0-600cGy for photons and 0-300cGy for electrons. Counts were measured using both the original drawer and the newly redesigned drawer and corrected for background PMT signal.

Results: Using corrected counts, photons exhibited a 33% average increase in measured signal (Range 28%-62%) and electrons exhibited a 34% average increase in measured signal (Range 29%-48%). The near linear response of counts versus dose delivered was seen in all setups. The mean coefficient of variation for all exposed OSLDs was 0.0204/0.0149 for photons and 0.0135/0.0136 for electrons using the original and the redesigned drawer respectively. A reduced CoV for photons utilizing the updated drawer was seen in the 15cGy-100cGy and ≥300cGy ranges.

Conclusion: The new drawer system allows for an approximately 33% increase in signal from current OSLD measurements. This demonstrated an increased precision of photon measurements, however there was no demonstrable improvement with electron measurements.

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