Effectiveness of robust optimization in volumetric modulated arc therapy using 6 and 10 MV flattening filter-free beam therapy planning for lung stereotactic body radiation therapy with a breath-hold technique. (5th May 2020)

• Record Type: Journal Article
• Authors: Miura, Hideharu; Ozawa, Shuichi; Doi, Yoshiko; Nakao, Minoru; Kubo, Katsumaro; Kenjo, Masahiko; Nagata, Yasushi
• Is Part Of: Journal of radiation research. Volume 61:Number 4(2020:Jul.)
• Page Start: 575
• Page End: 585
• Publication Date: 2020-05-05
• Subjects: robust optimization -- lung -- VMAT -- dose uncertainty -- perturbed dose; Radiology, Medical -- Periodicals; Radiobiology -- Periodicals; Radiation -- Periodicals; 616.0757
• DOI: 10.1093/jrr/rraa026
• Languages: English
• ISSNs: 0449-3060

Abstract

Abstract: We investigated the feasibility of a robust optimization with 6 MV X-ray (6X) and 10 MV X-ray (10X) flattening filter-free (FFF) beams in a volumetric modulated arc therapy (VMAT) plan for lung stereotactic body radiation therapy (SBRT) using a breath-holding technique. Ten lung cancer patients were selected. Four VMAT plans were generated for each patient; namely, an optimized plan based on the planning target volume (PTV) margin and a second plan based on a robust optimization of the internal target volume (ITV) with setup uncertainties, each for the 6X- and 10X-FFF beams. Both optimized plans were normalized by the percentage of the prescription dose covering 95% of the target volume (D95% ) to the PTV (1050 cGy × 4 fractions). All optimized plans were evaluated using perturbed doses by specifying user-defined shifted values from the isocentre. The average perturbed D99% doses to the ITV, compared to the nominal plan, decreased by 369.1 (6X-FFF) and 301.0 cGy (10X-FFF) for the PTV-based optimized plan, and 346.0 (6X-FFF) and 271.6 cGy (10X-FFF) for the robust optimized plan, respectively. The standard deviation of the D99% dose to the ITV were 163.6 (6X-FFF) and 158.9 cGy (10X-FFF) for the PTV-based plan, and 138.9 (6X-FFF) and 128.5 cGy (10X-FFF) for the robust optimized plan, respectively. Robust optimized plans with 10X-FFF beams is a feasible method to achieve dose certainty for the ITV for lung SBRT using a breath-holding technique.