First Experience With Real-Time EPID-Based Delivery Verification During IMRT and VMAT Sessions

Journal Article · Sun Nov 01 04:00:00 EST 2015 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2015.07.2271· OSTI ID:22644974

Fuangrod, Todsaporn ^[1]; Van Uytven, Eric; McCurdy, Boyd M.C.; Beek, Timothy van ^[2]; Bhatia, Shashank ^[3]; Greer, Peter B. ^[4]

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1. Faculty of Engineering and Built Environment, School of Electrical Engineering and Computer Science, University of Newcastle, New South Wales (Australia)
2. Division of Medical Physics, CancerCare Manitoba, Winnipeg, Manitoba (Canada)
3. Department of Radiation Oncology, Calvary Mater Newcastle Hospital, Newcastle, New South Wales (Australia)
4. Faculty of Science and Information Technology, School of Mathematical and Physical Sciences, University of Newcastle, New South Wales (Australia)

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.

• OSTI ID: 22644974
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 93; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BIOMEDICAL RADIOGRAPHY
EXTERNAL BEAM RADIATION THERAPY
IMAGES
LINEAR ACCELERATORS
NEOPLASMS
VERIFICATION