The Dosimetric Comparison of Planning Target Volume between Helical Tomotherapy and Volumetric Modulated Arc Therapy in Lung Cancer

Abstract

Backgrounds: Radiotherapy is an essential component in lung cancer treatment. Locally advanced lung cancer always presents with large tumor size and needs advanced technique in radiotherapy planning. Helical tomotherapy (HT) and volumetric modulated arc therapy (VMAT) are advanced techniques of delivering intensity-modulated radiotherapy which high dose to target and low dose for organs at risk (OARs) are expected. Objectives: To compare the planning target volume (PTV) dosimetric result between HT and VMAT treatment planning for advanced lung cancer. Material and methods: 4D CT simulation was used for seven lung cancer HT and VMAT treatment plannings. The PTV prescription dose was 6 MV photon, 60 Gy in 30 fractions. The HT and VMAT plans were generated using VoLO™ V.5.0.1.24 and Monaco V.5.11 treatment planning respectively. The dose constraints for PTV was reviewed using ICRU 83 recommendation. The homogeneity index (HI) and target coverage (TC) were absoluted to evaluate the quality of the plan. Results: There was no statistical difference between HT and VMAT PTV dose. The means HI in HT and VMAT techniques were 9.32 and 9.88, respectively (p = 0.313). VMAT had statistically significant better in TC with the mean TC of HT and VMAT of 0.61 and 0.86, respectively (p < 0.001). Conclusions: According to ICRU Report 83, this study shows that HT and VMAT provide similar quality of PTV dose for advanced lung cancer. However, VMAT shows superior in mean TC.