Abstract：Objective Based on the Halcyon accelerator, a comparative study of the dosimetric difference of volumetric intensitymodulated
arc therapy (VMAT) plans with different numbers of arcs (2Arc, 3Arc, 4Arc). Methods CT datasets of twenty patients
with cervical cancer after surgery were investigated and PTV and organs at risk were contoured. Based on the same CT datasets, the
2Arc, 3Arc, and 4Arc VMAT plans were designed to evaluate the dose distribution of PTV and organs at risk. Results All the 2Arc,
3Arc, and 4Arc plans resulted in equivalent target coverage and achieved prescription requirements. The 4Arc group had the highest
target conformity index (CI) and the lowest Homogeneity index (HI) (P<0.05). The mean dose of bladder, rectum, small intestine
and bone marrow has statistically significant reduced in the 4Arc group (P<0.05). For the dose of spinal cord D0.1cc and left femoral
head D5, the 4Arc group was the lowest with statistically difference (P<0.05). The difference in the right femoral head D5 was no
significant between 3Arc group and 4Arc group (P>0.05). There was no significant difference in the average MU number between
3Arc group and 4Arc group (P>0.05). Conclusion Patients with cervical cancer after surgery can obtain a better dose distribution by
using the 4Arc VMAT plan, in which more homogeneous dose distribution in PTV, more accurate dose delivery, and the lower mean
dose in organs at risk could be achieved. MU counts and treatment time have not significant increased. It is recommended to use 4Arc
VMAT plan after comprehensive consideration.
张杰，杨波，于浪，汪之群，王贝，李文博，梁永广，邱杰. 基于Halcyon不同旋转弧数量的VMAT计划剂量学比较[J]. 中国医疗设备, 2021, 36(4): 36-40.
ZHANG Jie, YANG Bo, YU Lang, WANG Zhiqun, WANG Bei, LI Wenbo, LIANG Yongguang, QIU Jie. Dosimetric Comparison of VMAT Plans Based on Halcyon with Different Rotating Arcs. China Medical Devices, 2021, 36(4): 36-40.
