Document Type : Original Paper
Department of Radiotherapy, Bangalore Baptist Hospital, Bangalore, India, Department of Applied Physics, Karunya institute of technology and sciences, Coimbatore, India
Department of applied Physics, Karunya Institute of Technology and Sciences, Coimbatore-641 114 Tamilnadu India
Chief Medical Physicist Department of Radiation Oncology Fortis Hospital Sector 62, Phase 8, SAS Nagar Moahli-160062 Punjab India
Department of Radiotherapy, Bangalore Baptist Hospital, Bangalore, India
Department of Radiation oncology, Tawam Hospital, Abu Dhabhi, UAE
Department of Community Medicine, Bangalore Baptist Hospital, Bangalore, India
The aim of the study is to compare target coverage and critical structure dose difference between various dose computing algorithms with small segment dose calculation in Intensity Modulated Radiation Therapy(IMRT) and large segment dose calculation in 3-Dimensional Conformal Radiation Therapy(3DCRT) treatment plan for Head and Neck (H&N) tumour.
Methods and Materials:
For the present study, thirty-eight H&N cancer patients were selected retrospectively. Twenty-seven patients were planned with IMRT plan using Monte Carlo(MC) algorithm and eleven patients with 3DCRT plan using Collapsed Cone/Superposition(CCS) algorithm. IMRT plan was recalculated with Pencil Beam(PB) and the 3DCRT plan was recalculated with MC and PB algorithms. Independent student t-test was performed as a part of statistical analysis for dosimetric comparison of the p-value.
In the IMRT plan, mean dose, Conformity Index(CI), D2%, D98% and D50% showed significant differences in p-values (p<0.05), but the critical structure did not have a significant difference in p-value between the MC and PB algorithms, except Planning Risk Volume(PRV) spine. In the 3DCRT plan, mean dose, CI, Homogeneity Index(HI), D98%, D50% and all the critical structures showed no statistically significant p-values (p<0.05) between the CCS with MC and CCS with PB algorithms.
The study concludes that in the IMRT treatment technique, PB algorithms overestimate the dose when compared with the MC algorithm, even in the head and neck treatment area. For 3DCRT treatment plans, CCS, MC and PB algorithms showed no statistically significant differences between them. Moreover, this study ensured the accuracy of various dose calculation algorithms in H&N radiotherapy.