Department of Radiation Oncology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India , jjyothi.nagesh@manipal.edu
Abstract: (13 Views)
Background:The purpose is to identify the standard minimum segment width [MSW] in terms of planning outcomes of Volumetric modulated arc therapy [VMAT] in patients with Head and Neck Carcinoma [HNC]. Material and Methods: A retrospective analysis was conducted using planning computed tomography scans from 15 patients diagnosed with head and neck carcinoma. Four separate VMAT plans, utilizing MSW of 0.5 cm, 1.0 cm, 1.5 cm, and 2.0 cm, were created in the Monaco Treatment Planning system [TPS]version 5.11.03. Target volume and critical structures were optimized with the same criteria. The comparison focused on Conformity Index [CI], Homogeneity Index [HI], target volume coverage, dose to Organs at risk [OARs], and total Monitor units (MUs). Data analysis was performed using Jamovi software. At p<0.05, statistical significance was established. Results: MSW of 1.0 cm plans showed significantly enhanced planning target volume [PTV] coverage [p=0.021], fewer monitor units [p=0.03], and an optimal combination of Conformity [CI = 0.816±0.214] and Homogeneity [HI = 1.065±0.017]. Furthermore, the spinal cord received a substantially lower maximum dose in plans created with 0.5 cm and 1.0 cm MSWs compared to those with wider segment widths [p=0.017]. Conclusions: Among the configurations tested, the 1.0 cm MSW offered the most favorable balance between precise target coverage, organ-at-risk sparing, and overall treatment delivery efficiency for head and neck cancer using VMAT planning.