Application of ASC algorithm in volumetric modulated arc therapy for nasopharyngeal carcinoma(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2020年第5期
- Page:
- 545-551
- Research Field:
- 医学影像物理
- Publishing date:
Info
- Title:
- Application of ASC algorithm in volumetric modulated arc therapy for nasopharyngeal carcinoma
- Author(s):
- ZHU Hao1; JIA Xiaobin2; ZHU Weihua1; ZHANG Zhen1; HAN Zengwei2
- 1.Clinical Application Training Department of Varian Medical Systems, Inc., Beijing 102600, China 2.Department of Radiotherapy, the
Ninth Peoples Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai 201900, China
- Keywords:
- nasopharyngeal carcinoma volumetric modulated arc therapy aperture shape controller visual scripting aperture
irregularity plan complexity index
- PACS:
- R815；R811.1
- DOI:
- 10.3969/j.issn.1005-202X.2020.05.004
- Abstract:
- Objective To analyze and evaluate the application of aperture shape controller (ASC) algorithm in volumetric modulated
arc therapy (RapidArc) for nasopharyngeal carcinoma based on ESAPI and visual scripting. Methods The clinical information
of 40 patients with nasopharyngeal carcinoma was analyzed retrospectively, and Eclipse v15.5 treatment planning system was
used to design 6 RapidArc plans for each patient. The 6 groups of plans included control group (ASC-no), experimental group
Ⅰ (ASC-verylow), experimental group Ⅱ (ASC-low), experimental group Ⅲ (ASC-moderate), experimental group Ⅳ (ASC-high)
and experimental group Ⅴ (ASC-veryhigh), and the other optimization parameters of all plans were set as the same. The ESAPI
and visual scripting of Eclipse v15.5 were used to assess the dosimetric differences in target areas and organs-at-risk and further
analyze the variations of aperture irregularity and plan complexity index. Results No statistical difference was found in the
conformity index of PGTV69 between control group and experimental groups, but the homogeneity index (HI) of PGTV69 and
PCTV1 in experimental groups was higher than that in control group, with statistical differences (P<0.05), and the difference in
HI showed an increasing trend with the increase of ASC weight. For the HI of PCTV2, there were statistical differences between
control group and experimental groups II, III and IV (P<0.05). Compared with the dosimetric parameters of organs-at-risk in control
group, there were statistical differences in the Dmaxof spinal cord, the Dmean of larynx and parotid-L in experimental group V (P<
0.05) the Dmean of brainstem in experimental group I (P<0.05) the V30 of parotid-R in experimental group II (P<0.05) the Dmean
of lens in experimental groups I and V (P<0.05) and the Dmax of pituitary in experimental groups III, IV and V (P<0.05). Among the experimental groups, there was statistical differences in total machine monitors between experimental group I and experimental
group II (P<0.05).As theASC weight increasing, both aperture irregularity and plan complexity index showed a decreasing trend.
Conclusion ASC algorithm improves plan complexity index and aperture irregularity.Among them, theASC of low weight reduces
machine monitors, and the ASC of high weight affects the homogeneity of target areas and other dosimetric indicators. Based on
the comprehensive consideration of plan quality and delivery efficiency, the ASC weight is recommended to be set as verylow,
low and moderate for nasopharyngeal carcinoma and other complex radiotherapy plans.
Last Update: 2020-06-03