Dosimetric evaluation of a novel polymer gel dosimeter for proton therapy

Journal Article · Sat May 15 04:00:00 EDT 2010 · Medical Physics

DOI:https://doi.org/10.1118/1.3388869· OSTI ID:22100582

Zeidan, O. A.; Sriprisan, S. I.; Lopatiuk-Tirpak, O.; Kupelian, P. A.; Meeks, S. L.; Hsi, W. C.; Li, Z.; Palta, J. R.; Maryanski, M. J. ^[1]

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1. M. D. Anderson Cancer Center Orlando, Orlando, Florida 32806 (United States)

Purpose: The aim of this study is to evaluate the dosimetric performance of a newly developed proton-sensitive polymer gel formulation for proton therapy dosimetry. Methods: Using passive scattered modulated and nonmodulated proton beams, the dose response of the gel was assessed. A next-generation optical CT scanner is used as the readout mechanism of the radiation-induced absorbance in the gel medium. Comparison of relative dose profiles in the gel to ion chamber profiles in water is performed. A simple and easily reproducible calibration protocol is established for routine gel batch calibrations. Relative stopping power ratio measurement of the gel medium was performed to ensure accurate water-equivalent depth dose scaling. Measured dose distributions in the gel were compared to treatment planning system for benchmark irradiations and quality of agreement is assessed using clinically relevant gamma index criteria. Results: The dosimetric response of the gel was mapped up to 600 cGy using an electron-based calibration technique. Excellent dosimetric agreement is observed between ion chamber data and gel. The most notable result of this work is the fact that this gel has no observed dose quenching in the Bragg peak region. Quantitative dose distribution comparisons to treatment planning system calculations show that most (>97%) of the gel dose maps pass the 3%/3 mm gamma criterion. Conclusions: This study shows that the new proton-sensitive gel dosimeter is capable of reproducing ion chamber dose data for modulated and nonmodulated Bragg peak beams with different clinical beam energies. The findings suggest that the gel dosimeter can be used as QA tool for millimeter range verification of proton beam deliveries in the dosimeter medium.

• OSTI ID: 22100582
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 5 Vol. 37; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
62 RADIOLOGY AND NUCLEAR MEDICINE
BENCHMARKS
BRAGG CURVE
CALIBRATION
DEPTH DOSE DISTRIBUTIONS
DOSEMETERS
DOSIMETRY
IONIZATION CHAMBERS
IRRADIATION
PERFORMANCE
PLANNING
POLYMERS
PROTON BEAMS
QUENCHING
RADIATION DOSES
RADIOTHERAPY
READOUT SYSTEMS
STOPPING POWER
VERIFICATION
WATER