AUTHOR=Zhang Shu , Zhan Weiyi , Zeng Ni , Yang Jiangping , Xiong Maoqi , Liao Wenjun , Chen Nianyong , Xiao Jianghong 

TITLE=Dosimetric comparison in sparing normal tissue dosage by using auto-SBRT planning in oligo liver tumors

JOURNAL=Frontiers in Oncology

VOLUME=13

YEAR=2023

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2023.1273042

DOI=10.3389/fonc.2023.1273042

ISSN=2234-943X

ABSTRACT=<sec><title>Purpose</title><p>The study aimed to compare the dosimetric distribution of VMAT plans by increasing the number of half arcs in liver SBRT and investigate the effect by using automatic plan software in plan optimization.</p></sec><sec><title>Method</title><p>Thirty-one patients with oligo liver tumors were randomly selected. VMAT treatment plans with different numbers of coplanar half arcs were generated.</p></sec><sec><title>Result</title><p>Adding arcs significantly increased the PTV, <italic>D<sub>2%</sub></italic>, <italic>D<sub>50%</sub></italic>, and <italic>CI</italic>, but sacrificed the plan homogeneity. It also decreased the maximum dose of normal tissues such as the stomach, duodenum, and spinal cord and reduced <italic>D<sub>mean</sub></italic>, <italic>D<sub>500cc</sub></italic>, and <italic>D<sub>700cc</sub></italic> for the liver. Nevertheless, the diminishing effect gradually decayed into three arcs. Meanwhile, the addition of arcs substantially extended the beam-on time.</p></sec><sec><title>Conclusion</title><p>In the context of SBRT for oligo liver tumors, increasing the number of coplanar half arcs will improve PTV conformity and offer better protection for OARs, albeit at the expense of increased treatment duration. Considering the trade-off between plan quality and treatment efficiency, a three-arc plan may be more suitable for clinical implementation.</p></sec>