Table of Contents
Journal of Radiotherapy
Volume 2014, Article ID 743150, 5 pages
http://dx.doi.org/10.1155/2014/743150
Research Article

Accuracy of Dose Delivery in Multiple Breath-Hold Segmented Volumetric Modulated Arc Therapy: A Static Phantom Study

1Department of Radiology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
2Faculty of Health Sciences, Institute of Medical Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan
3Department of Radiotherapy, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
4Department of Radiation Oncology, Kouseiren Takaoka Hospital, 5-10 Eirakucho, Takaoka, Toyama 933-8555, Japan

Received 6 June 2014; Accepted 9 September 2014; Published 16 September 2014

Academic Editor: Oliver Micke

Copyright © 2014 Kimiya Noto et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose. Accuracy of dose delivery in multiple breath-hold segmented volumetric modulated arc therapy (VMAT) was evaluated in comparison to noninterrupted VMAT using a static phantom. Material and Methods. Five VMAT plans were evaluated. A Synergy linear accelerator (Elekta AB, Stockholm, Sweden) was employed. A VMAT delivery sequence was divided into multiple segments according to each of the predefined breath-hold periods (10, 15, 20, 30, and 40 seconds). The segmented VMAT delivery was compared to noninterrupted VMAT delivery in terms of the isocenter dose and pass rates of a dose difference of 1% with a dose threshold of 10% of the maximum dose on a central coronal plane using a two-dimensional dosimeter, MatriXX Evolution (IBA Dosimetry, Schwarzenbruck, Germany). Results. Means of the isocenter dose differences were 0.5%, 0.2%, 0.2%, 0.0%, and 0.0% for the beam-on-times between interrupts of 10, 15, 20, 30, and 40 seconds, respectively. Means of the pass rates were 85%, 99.9%, 100%, 100%, and 100% in the same order as the above. Conclusion. Our static phantom study indicated that the multiple breath-hold segmented VMAT maintains stable and accurate dose delivery when the beam-on-time between interrupts is 15 seconds or greater.