2Department of Radiation Oncology, Başkent University Faculty of Medicine, Adana Research and Treatment Center, Adana-Türkiye
3Department of Radiation Oncology, Başkent University Faculty of Medicine, Ankara-Türkiye DOI : 10.5505/tjo.2022.3702 OBJECTIVE
Volumetric arc therapy (VMAT) is advantageous for stereotactic body radiotherapy (SBRT) delivery; however, it is still unknown which rotational method is optimal for the treatment of liver metastases. This study aims to compare the dosimetric data of SBRT plans with VMAT techniques and helical tomotherapy (HT) in 18 liver metastasis patients.
METHODS
Three plans were generated: VMATM was generated with Monaco Treatment Planning System (TPS),
VMATE with an Eclipse TPS, and HT plans were generated using a Hi-Art Tomotherapy system. The
prescribed dose was 54 Gy delivered in three fractions. The planning target volume (PTV) doses and
organs at risk (OAR) doses were compared between three plans.
RESULTS
All plans met the criteria for PTV coverage. Maximum PTV doses were significantly higher in VMATM
plan, and minimum PTV doses were significantly lower in VMATE plan. The dose conformity and homogeneity
indices of PTV were better in VMATE plan. Only mean bowel maximum dose was significantly
higher in HT plan compared to VMATM plan only. The liver Dmean were significantly higher in
PTV larger than 50 cm³. Liver Dmean in PTV >50 cm³ was significantly less in VMATM plan compared to
HT (p=0.04) and VMATE plans (p=0.04).
CONCLUSION
All three plans met the criteria for PTV coverage with no significant difference in OARs doses. VMATE
plan yielded better homogeneity and conformity in PTV compared to VMATM and HT, and healthy liver
tissue was better spared especially in larger tumors (>50 cm³) with VMATE plans.