TITLE:
Dosimetric and Efficiency Comparisons between Volumetric Modulated Arc Therapy and IMRT for Cervical-Thoracic Esophageal Cancers
AUTHORS:
Yuxin Duan, Xi Liu, Zhongqiang Liu, Ning Zhan, Zongda Zhu, Zhenxiang Deng
KEYWORDS:
Esophageal, Dosimetric, IMRT, VMAT
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.12 No.11,
November
2,
2021
ABSTRACT: Purpose: This study aims to evaluate the treatment plans of Volumetric-modulated arc therapy (VMAT)
and intensity-modulated radiation therapy (IMRT) techniques for cervical-thoracic esophageal cancers. Methods and Materials: Sixty patients were retrospectively identified.
Several parameters were evaluated based on target conformity and
dose-volume histograms of organs at risk (lung, spinal cord, and heart). A
phantom for time comparison was also assessed for each plan. Results: The IMRT plans (5f-IMRT: V95% = 99.4 ±
0.3, 7f-IMRT: V95% = 99.8 ± 0.1) results in better PTV coverage than RA plans
(Single-arc: V95% = 95.8 ± 3.2, Double-arc: V95% = 95.4 ± 2.3). The target dose
conformity of the 5f-IMRT plan was inferior to all plans (CI = 70.4 ± 7.1). The
Single-arc plan achieved the best conformity (CI = 72.5 ± 4.6), whereas the
Double-arc plan (CI = 72.1 ± 5.1) was slightly inferior to the Single-arc plan
but superior to the 7f-IMRT plan (CI = 71.7 ± 8.6). The total MU was reduced by 42.1% in VMAT plan. The average MU
needed to deliver the dose of 60 Gy for Single-arc (423.5 ± 52.1 MU) was found
to be the least. Similarly, the average MU for the 5f-IMRT, 7f-IMRT and
Double-arc were 868.2 ± 182.0 MU, 870.0 ± 225.3 MU and 548.8 ± 47.2 MU,
respectively. The delivery time in VMAT plans was reduced
from 193.8 seconds to 99.2 seconds by
around 48.8% compared to IMRT plans. Conclusion: For similar PTV parameters, VMAT delivers a
lower dose to organs at risk than IMRT in a shorter time, and this has
warranted clinical implementation.