SU‐E‐T‐24: Remote, Automated Daily Delivery Verification of Volumetric Modulated Arc Therapy Treatments Using a Commercial Record and Verify System

• Published in: Medical Physics 2011-06, Vol.38 (6), p.3490-3491
• Main Authors: Fontenot, J, Gibbons, J
• Format: Article
• Language: English
• Subjects: Collimators; Computer software; Control systems; Data analysis; Dosimetry; Drug delivery; Linear accelerators; Multileaf collimators; Radiation therapy; Radiation treatment
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.3611974

Purpose: Volumetric modulated arc therapy (VMAT) is an effective but complex technique for delivering radiation therapy. VMAT relies on precise combinations of dose rate, gantry speed, and multi‐leaf collimator (MLC) shapes to deliver intensity modulated patterns. Such complexity warrants the development of correspondingly robust performance verification systems. In this work, we report on the feasibility of using data collected from a commercial record and verify system to perform remote, automated daily delivery verification of volumetric modulated arc therapy (VMAT) treatments. Methods: The performance verification software system consists of 3 main components: (1) a query module to retrieve daily MLC, gantry, and jaw positions reported by the linear accelerator control system (Elekta, Crawley, UK) to the record and verify system (Mosaiq, Elekta, Mountain View, CA, USA), (2) an analysis module to read the daily delivery report generated from the database query module, compare the reported treatment positions against the planned positions, and compile delivery position error reports, and (3) a reporting module to display graphical reports initiated by a user or to automatically alert authorized users when pre‐defined tolerance values are exceeded. The utility of the system was investigated through analysis of patient data collected at our clinic. Results: Nearly 2,500 VMAT fractions have been analyzed with the delivery verification system at our institution. The average percentage of reported MLC leaf positions within 3 mm, gantry positions within 2 degrees and jaw positions within 3 mm of their planned positions was 92.9 +/− 5.5%, 95.9 +/− 2.9%, and 99.7 +/− 0.6%, respectively. The level of agreement between planned and reported MLC positions decreased for treatment plans requiring larger MLC leaf movements between control points. Conclusions: The delivery verification system holds the potential to provide an effective and low‐cost quality assurance tool that improves patient safety.