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A Flexible SiO2 Fiber Detector Array for Proton Beam Range Verification

T Zhu

T Zhu*, H Lin , M Kim , A Dimofte , A Darafsheh , University of Pennsylvania, Philadelphia, PA


SU-K-108-1 (Sunday, July 30, 2017) 4:00 PM - 6:00 PM Room: 108

Purpose: Basic performance for a fiber-optic based detector array using SiO2 fibers were evaluated for use in proton beam dosimetry.

Methods: A SiO2 fiber optic-based detector array was developed in-house by inserting each fiber into a custom-made 2D flexible holder with 1 cm spacing. The optical signal from the proton beam was detected by a photodiode and subsequently amplified. Dosimetry performance was measured by investigating percentage depth dose and beam profile and compared to reference ion chamber measurements. The variations in transmission between fibers was determined by using a reference beam measurement. The calibration factor for each channel was defined as the ratio between the measured value of channel 1 and the measured value of each channel. The calibration factor was multiplied to measured beam data so that the transmission differences are taken into account.

Results: The dosimetry results of the detector array point measurements are in good agreement with known ion chamber measurements. For profile measurements of a 10x10 cm field, the maximal deviation of the profile is 5%. Each individual channel calibration factor was characterized and range between 0.78 and 1.66. PDD measurements were also performed and compared with ion chamber measurements.

Conclusion: The SiO2 fiber detector array is feasible for the dosimetry measurements necessary for proton beam therapy. Dose distribution along or perpendicular to the beam path can be measured using the detector array system.

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