Dosimetric analysis and comparison of volumetric-modulated arc therapy versus intensity-modulated radiation therapy for liver carcinoma

Aim: This study dosimetrically compared volumetric-modulated arc therapy (VMAT) to intensity-modulated arc therapy (IMRT) for patients with liver carcinoma. Materials and methods: Ten patients with liver carcinoma previously treated with IMRT or VMAT were retrospectively selected for this study. Each patient received a total dose of 54 Gy in 1·8 Gy fractions. Dosimetric evaluations for each patient were performed using the dose–volume histograms (DVHs) for planning target volumes (PTVs) and organs at risk (OAR). All dosimetric parameters were statistically analysed using mean values, standard deviations and p-values for determining the significance. The conformality index (CI) and homogeneity index (HI) were calculated and compared. For efficiency evaluation, monitor units (MUs) and beam on times (BOT) were recorded. Results: Compared to IMRT, VMAT plans showed significant differences in the heterogeneity with p < 0·01 and insignificant differences in both conformality and normal tissue sparing. VMAT required marginally fewer mean MU and shorter BOT when compared to IMRT with insignificant differences. Conclusions: For radiation therapy treatment of liver carcinoma, IMRT and VMAT can achieve similar PTV coverage and normal tissue sparing. Treatment time is only marginally shorter with VMAT versus IMRT with insignificant differences.