Automated Non-coplanar Volumetric Modulated Arc Therapy Planning for Maxillary Sinus Carcinoma

Background/Aim: Dosimetric parameters in volumetric modulated arc therapy (VMAT), non-coplanar VMAT (NC-VMAT), and automated NC-VMAT (HyperArc, HA) were compared for patients with maxillary sinus carcinoma (MSC). Patients and Methods: Twenty HA plans were generated to deliver 70.4, 64, and 46 Gy for planning target volumes with high (PTV1), intermediate (PTV2), and low risk (PTV3), respectively. The VMAT and NC-VMAT plans were retrospectively generated using the same optimized parameters as those used in the HA plans. Results: For PTV1, the three treatment plans provided comparable target coverages. For PTV2, the D95%, D99%, and Dmin in the HA plans (64.7 & PLUSMN;1.2, 62.7 & PLUSMN;2.1 and 54.6 & PLUSMN;6.2 Gy, respectively) were significantly higher (p<0.05) than those in the VMAT plans (64.3 & PLUSMN;1.7, 61.9 & PLUSMN;2.4 and 52.9 & PLUSMN;6.4 Gy, respectively). The NC-VMAT and HA plans provided significantly higher (p<0.05) dosimetric parameters for PTV3 than those in the VMAT plans, and D99% in the HA was significantly higher than that in the NC-VMAT plans (52.5 & PLUSMN;3.0 vs. 51.8 & PLUSMN;2.7 Gy, p<0.05). The doses to the brain and brainstem were lowest in the HA plans (p<0.05). Moreover, dosimetric parameters of the contralateral organs (lens, optic nerve, retina, and parotid) were lower in the HA plans than in the VMAT and NC-VMAT plans. Conclusion: The HA plans provided the best target coverage and OAR sparing compared with VMAT and NC-VMAT plans for patients with MSC.