Comparative Dosimetric Analysis of conventional 3DCRT and VMAT for Head and Neck Cancer

Abstract

Introduction: Advancements in radiation oncology improve the outlook for patients with head and neck cancer which allowed to escalate the dose of radiation to tumours while minimizing the dose to surrounding healthy tissues. This study aims comparison of radiotherapy treatment planning of 3 DCRT and VMAT for head and neck cancer.Methods: Prospective study conducted on fifty patients of head and neck cancer in which 25 patients were treated with 3 DCRT and 25 patients treated with VMAT. Both plans were evaluated to compare the efficiency of VMAT and 3 DCRT dosimetrically in terms of PTV volume, homogeneity index, conformity index and doses to organs at risk. Results: Dose D98% for PTV66 was 59.39 Gy and 51.82 for VMAT and 3DCRT respectively. Conformity index was 1.0816 and 1.4472 for VMAT and 3DCRT plans respectively and the difference was statistically significant. Homogeneity index was 0.1473 for VMAT and 0.2997 for 3DCRT which proves that VMAT was more homogeneous. OARs sparing was also better with VMAT compared to 3DCRT especially the OARs which were very close to target volume especially parotid glands, Brainstem and optic nerve. Conclusion: Compared to 3DCRT plans, VMAT plan produced significantly better target coverage, homogeneous as well as dose conformity. Doses to organs at risk such as spinal cord and parotid glands were also reduced. Besides, the delivery of VMAT treatment was more efficient.