(Tuesday, 7/31/2018) 10:30 AM - 11:00 AM
Room: Exhibit Hall | Forum 4
Purpose: The publication of TRS-483 provided code of practice and the data for most detectors in the market. It is found that plastic scintillator detector (PSD) W1 is an ideal choice; however this cannot be used for beam scanning. Therefore, the goal of this study is to characterize the Exradin plastic scintillator (W2) for small field scanning dosimetry.
Methods: A 6MV beam from a Varian-Edge linac was used to collect data for characterization of a W2 detector. Cerenkov light radiation (CLR) is corrected through a separate new electrometer system. The parameters investigated include the dose and dose rate linearity, dose profile, output factors, and temperature response. These are compared with the EBT-3 film for depth dose and profiles for fields in the range of 0.5-5.0 cm² square fields. Additionally, characteristics are compared with W1 for a wide range of field sizes.
Results: The dose linearity measured with 600 MU/min dose rate showed very low variations (<0.5%) even for 1 MU. Similar results were seen for dose rate linearity. The output factors comparison between the W2 and W1 showed up to 1% variation, except for the 0.5x0.5cm² field size with -1.4% differences. Indicating that W2 is suitable for small field dosimetry and provides similar characteristics to W1. The temperature response showed up to 3% variation when the temperature was varied from 15°C to 36°C, normalized to 20°C. The profile using the W2 and EBT-3 film showed good correlation in the penumbra and umbra region.
Conclusion: The new scanning W2 scintillator showed superb constancy, and has similar radiation response characteristics for small field dosimetry as W1 scintillator. The W2 detector satisfactorily provides opportunity for photon beam scanning.
Keywords
Absolute Dosimetry, Scintillators, Small Fields
Taxonomy
Not Applicable / None Entered.
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