West Asia Organization for Cancer Prevention (WAOCP), APOCP's West Asia Chapter. Asian Pacific Journal of Cancer Prevention 1513-7368 25 4 2024 04 01 Comparison between Volumetric Modulated arc Therapy based Coplanar and Noncoplanar Planning for Stereotactic Body Radiation Therapy of Liver 1383 1390 91109 10.31557/APJCP.2024.25.4.1383 EN Anjum Nisha Department of Radiotherapy and Oncology, Medical Radiation Physics Program, Manipal College of Health Professions(MCHP), Manipal Academy of Higher Education(MAHE), Manipal, Karnataka, India. 0009-0007-2070-0775 Shambhavi C Department of Radiotherapy and Oncology, Medical Radiation Physics Program, Manipal College of Health Professions(MCHP), Manipal Academy of Higher Education(MAHE), Manipal, Karnataka, India. 0000-0001-8862-4552 Jyothi Nagesh Radiotherapy and Oncology, Senior Grade Lecturer, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, Karnataka, India. 0000-0003-4308-8404 Sarath S Nair Radiotherapy and Oncology, Senior Grade Lecturer, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, Karnataka, India. 0000-0002-0012-6020 Journal Article 2023 12 12 Background: The study aims to investigate potential dosimetric benefits between non-coplanar and coplanar beam arrangements of Volumetric-Modulated Arc Therapy (VMAT) plans for liver stereotactic body radiotherapy (SBRT). Methods: Thirteen patients who had undergone liver SBRT treatment in our department were chosen retrospectively for the study. Two sets of SBRT-VMAT plans namely, non-coplanar (NC-VMAT) and Coplanar (C-VMAT) were generated in Monaco(v5.11) planning system for Elekta Versa HD Linac using unflatten 6MV photon. The NC-VMAT plans were created by two/three non-coplanar partial arcs with couch rotation of ±150 and had an arc span of 1300 to 1600 whereas the C-VMAT plans consisted of a full arc. Both plans were compared by statistically analyzing various dosimetric and technical parameters. Results: There is no statistically significant difference observed between the C-VMAT and NC-VMAT plans for planning target volume (PTV) coverage. However, the spine dose (D1cc) was much less in the NC-VMAT plan compared to the C-VMAT plan, with mean values of 6.127 ± 3.08Gy and 9.058 ± 4.76Gy, respectively (p-value=0.002). The low dose spillage to the healthy tissue was compared by the volume receiving 5Gy (V5Gy) and 10Gy (V10Gy). V5Gy of the NC-VMAT plan was 2399.23±1870.76cc while that of C-VMAT plans was 2835.36±1930.20cc with the p-value <0.001. Moreover, the monitor units(MU) were less with NC-VMAT than with C-VMAT SBRT plans (p=0.015). Conclusion: The plan quality of NC-VMAT plans was favorable compared to C-VMAT plans for liver SBRT especially in reducing spine dose, low dose spillage to healthy tissue, and MU.  https://journal.waocp.org/article_91109_87b4daa751ba930e72e4a54a0ced3364.pdf