|Table of Contents|

The dosimetry effect of the different positions of isocenter for volumetric modulated arc therapy treatment of cervical cancer

Journal Of Modern Oncology[ISSN:1672-4992/CN:61-1415/R]

Issue:
2022 01
Page:
101-106
Research Field:
Publishing date:

Info

Title:
The dosimetry effect of the different positions of isocenter for volumetric modulated arc therapy treatment of cervical cancer
Author(s):
DENG Jia1; WU Xiangyang1; CHANG Xiaobin1; ZHANG Kun1; HE Yaodong2; ZHAO Qiang1
1.Department of Radiation Oncology，Shaanxi Province Cancer Hospital，Shaanxi Xi'an 710061,China;2.School of Nuclear Science and Technology,Xi'an Jiaotong University,Shaanxi Xi'an 710049,China.
Keywords:
cervical cancer; isocenter optimization; volumetric modulated arc therapy; dosimetry
PACS:
R737.33
DOI:
10.3969/j.issn.1672-4992.2022.01.022
Abstract:
Objective:To quantify the impact of the different positions of isocenter for volumetric modulated arc therapy treatment of postoperative cervical cancer cervical cancer.Methods：Fifteen patients receiving postoperative radiotherapy for cervical cancer were selected.According to different position of isocenter,four VMAT plans were disigned on the same CT image,including Center plan,Y plan,X plan and X-Y plan.The position of isocenter had been distributed in 4 positions:symmetry center of the target(Center plan),9 cm up in the Y direction of the symmetry center(Y plan),7 cm to the left in the X direction of the symmetry center(X plan),9 cm up in the Y direction and 7 cm to the left in the X direction of the symmetry center(X-Y plan).The conformity index and homogeneity index of target areas,dosimetric differences of organs-at-risk and monitor units were compared.Results:The center plan and Y plan were satisfied with the clinical requirements.Compared with the center plan,the target coverage of the Y,X and X-Y plans decreased by 0.36%,15.48% and 6.52%,respectively.Compared with X plan and X-Y plan,conformity index(CI),uniformity index(HI),the Dmax of spinal cord,the V40 of bladder,the V40 of the rectem were better in Y plan,with statistical significance（P＜0.05）.Conclusion:In the design of the VMAT plan for postoperative cases of cervical cancer,the isocenter position is offset from the y-axis,which is suitable for clinical application.However,the isocenter position is offset in the x-axis direction,which is not suitable for clinical application because the OAR is at higher dose.

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Memo

Memo:
陕西省重点研发新计划项目（编号：2010KTZDSF02-03）
Last Update: 2021-12-02