Open AccessUse of a plastic scintillator detector for patient‐specific quality assurance of VMAT SRS
Author(s) -
Snyder Jesse D.,
Sullivan Rodney J.,
Wu Xingen,
Covington Elizabeth L.,
Popple Richard A.
Publication year - 2019
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.12705
Subject(s) - scintillator , isocenter , nuclear medicine , quality assurance , detector , confidence interval , imaging phantom , calibration , materials science , medicine , optics , physics , mathematics , statistics , external quality assessment , pathology
Purpose To evaluate a scintillator detector for patient‐specific quality assurance of VMAT radiosurgery plans. Methods The detector was comprised of a 1 mm diameter, 1 mm high scintillator coupled to an acrylic optical fiber. Sixty VMAT SRS plans for treatment of single targets having sizes ranging from 3 mm to 30.2 mm equivalent diameter (median 16.3 mm) were selected. The plans were delivered to a 20 cm × 20 cm x 15 cm water equivalent plastic phantom having either the scintillator detector or radiochromic film at the center. Calibration films were obtained for each measurement session. The films were scanned and converted to dose using a 3‐channel technique. Results The mean difference between scintillator and film was ‒0.45% (95% confidence interval ‒0.1% to 0.8%). For target equivalent diameter smaller than the median, the mean difference was 1.1% (95% confidence interval 0.5% to 1.7%). For targets larger than the median, the mean difference was ‒0.2% (95% confidence interval ‒0.7% to 0.1%).Conclusions The scintillator detector response is independent of target size for targets as small as 3 mm and is well‐suited for patient‐specific quality assurance of VMAT SRS plans. Further work is needed to evaluate the accuracy for VMAT plans that treat multiple targets using a single isocenter.