Dosimetric effect of grid size on stereotactic radiotherapy for liver cancer(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2021年第9期
- Page:
- 1057-1060
- Research Field:
- 生物材料与力学
- Publishing date:
Info
- Title:
- Dosimetric effect of grid size on stereotactic radiotherapy for liver cancer
- Author(s):
- DAI Wanting1; LI Xiangbin2; QUAN Hong1; TAN Zhijie1; WEI Wei2
- 1. School of Physics and Technology, Wuhan University, Wuhan 430072, China 2. Radiotherapy Center, Hubei Cancer Hospital,
Wuhan 430079, China
- Keywords:
- liver cancer stereotactic radiotherapy grid dosimetry Gamma passing rate
- PACS:
- R730.55；R811.1
- DOI:
- 10.3969/j.issn.1005-202X.2021.09.002
- Abstract:
- Objective To study the dosimetric effect of different grid sizes on stereotactic radiotherapy (SBRT) for liver cancer,
thereby providing an appropriate grid size for SBRT planning. Methods A retrospective analysis was performed on 10 cases of
liver cancer patients treated with VMAT-SBRT in Hubei Cancer Hospital from 2017 to 2020.With the same function and parameter
settings, treatment plans were designed with grid size of 1.0, 2.0, 3.0, 4.0 and 5.0 mm, respectively. The D95%, Dmean, conformity
index and gradient index of the target area, the Dmean of the whole liver, the V10, V20, V30 of normal liver, the Dmax of spinal cord and
calculation time for planning were compared. Moreover, the Gamma passing rates for the criteria of 3%/3 mm and 2%/2 mm were
compared. Results The grid size was changed by theAAAalgorithmof Eclipse system, and the results showed that with the increase
of grid size, the D95% of the target area had a downward trend, and gradient index tended to increase, but that the effects of grid
size on Dmean and conformity index were trivial. In terms of organs-at-risk sparing, better calculation results were obtained with
the grid size of 1.0 mm. The dose calculation time was increased greatly with the decrease of grid size and the Gamma passing
rates for both two criteria (2%/2 mm and 3%/3 mm) were decreases as the grid size increases. Conclusion Computational grid
size has different effects on the doses delivered to target areas and organs-at-risk, calculation time and Gamma passing rate. Based
on the comprehensive consideration on dose optimization, calculation time and verification passing rate, the grid size of 2.0 mm
is recommended in the clinical planning of VMAT-SBRT for liver cancer.
Last Update: 2021-09-27