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VMAT plus a few computer-optimized non-coplanar IMRT beams (VMAT+) tested for liver SBRT.

Authors :
Sharfo, Abdul Wahab M.
Dirkx, Maarten L.P.
Breedveld, Sebastiaan
Romero, Alejandra Méndez
Heijmen, Ben J.M.
Source :
Radiotherapy & Oncology. Apr2017, Vol. 123 Issue 1, p49-56. 8p.
Publication Year :
2017

Abstract

Purpose To propose a novel treatment approach, designated VMAT+, involving addition of <5 IMRT beams with computer-optimized non-coplanar orientations to VMAT, and evaluate it for liver Stereotactic Body Radiation Therapy (SBRT). VMAT+ is investigated as an alternative for (1) coplanar VMAT and (2) multi-beam non-coplanar treatment. Methods/materials For fifteen patients with liver metastases, VMAT+ plans were compared with (1) dual-arc VMAT and (2) 25-beam, non-coplanar treatment with computer-optimized beam orientations (25-NCP). All plans were generated fully automatically for delivery of the highest feasible tumor Biologically Effective Dose (BED). OAR doses, intermediate-dose-spillage, dose-compactness, and measured delivery times were evaluated. Results With VMAT+ the maximum achievable tumor BED was equal to that of 25-NCP. Conversely, VMAT resulted in a lower tumor BED in 5 patients. Compared to VMAT, VMAT+ yielded significant dose reductions in OARs. Intermediate-dose-spillage and dose-compactness were significantly improved by 9.8% and 17.3% ( p ≤ 0.002), respectively. Treatment times with VMAT+ were only enhanced by 4.1 min on average, compared to VMAT (8.4 min). Improvements in OAR sparing with 25-NCP, compared to VMAT+, were generally modest and/or statistically insignificant, while delivery times were on average 20.5 min longer. Conclusions For liver SBRT, VMAT+ is equivalent to time-consuming treatment with 25 non-coplanar beams in terms of achievable tumor BED. Compared to VMAT, OAR sparing and intermediate-dose-spillage are significantly improved, with minor increase in delivery time. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
01678140
Volume :
123
Issue :
1
Database :
Academic Search Index
Journal :
Radiotherapy & Oncology
Publication Type :
Academic Journal
Accession number :
122370820
Full Text :
https://doi.org/10.1016/j.radonc.2017.02.018