- Title
- First experience with real-time EPID-based delivery verification during IMRT and VMAT sessions
- Creator
- Woodruff, Henry C.; Fuangrod, Todsaporn; Van Uytven, Eric; McCurdy, Boyd M. C.; van Beek, Timothy; Bhatia, Shashank; Greer, Peter B.
- Relation
- International Journal of Radiation: Oncology - Biology - Physics Vol. 93, Issue 3, p. 516-522
- Publisher Link
- http://dx.doi.org/10.1016/j.ijrobp.2015.07.2271
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2015
- Description
- Purpose: Gantry-mounted megavoltage electronic portal imaging devices (EPIDs) have become ubiquitous on linear accelerators. WatchDog is a novel application of EPIDs, in which the image frames acquired during treatment are used to monitor treatment delivery in real time. We report on the preliminary use of WatchDog in a prospective study of cancer patients undergoing intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) and identify the challenges of clinical adoption. Methods and Materials: At the time of submission, 28 cancer patients (head and neck, pelvis, and prostate) undergoing fractionated external beam radiation therapy (24 IMRT, 4 VMAT) had ≥1 treatment fraction verified in real time (131 fractions or 881 fields). EPID images acquired continuously during treatment were synchronized and compared with model-generated transit EPID images within a frame time (~0.1 s). A χ comparison was performed to cumulative frames to gauge the overall delivery quality, and the resulting pass rates were reported graphically during treatment delivery. Every frame acquired (500-1500 per fraction) was saved for postprocessing and analysis. Results: The system reported the mean ± standard deviation in real time χ 91.1% ± 11.5% (83.6% ± 13.2%) for cumulative frame χ analysis with 4%, 4 mm (3%, 3 mm) criteria, global over the integrated image. Conclusions: A real-time EPID-based radiation delivery verification system for IMRT and VMAT has been demonstrated that aims to prevent major mistreatments in radiation therapy.
- Subject
- electronic portal imaging devices (EPIDs); WatchDog; cancer patients; intensity modulated radiation therapy (IMRT); volumetric modulated arc therapy (VMAT)
- Identifier
- http://hdl.handle.net/1959.13/1330320
- Identifier
- uon:26356
- Identifier
- ISSN:0360-3016
- Language
- eng
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