Evaluation of different volumetric-modulated arc therapy for the large planning target volume in T3 lung cancer
10.3760/cma.j.issn.1008-6706.2019.14.001
- VernacularTitle: Ⅲ期大体积肺癌不同容积调强放疗技术的研究
- Author:
Lei ZHANG
1
;
Guoping SHAN
1
;
Pu LI
1
;
Kainan SHAO
1
;
Yiwei YANG
1
;
Shiming ZHENG
1
;
Lu JIANG
2
Author Information
1. Department of Radiation Physics(Key Laboratory of Tumor Radiotherapy), Zhejiang Cancer Hospital, Hangzhou, Zhejiang 310022, China
2. Department of Radiology, Zhejiang Hospital, Hangzhou, Zhejiang 310022, China
- Publication Type:Journal Article
- Keywords:
Lung neoplasms;
Radiotherapy;
Radiotherapy, intensity-modulated;
Radiometry;
Radiotherapy dosage;
Radiation injuries;
Organs at risk;
Comparative study
- From:
Chinese Journal of Primary Medicine and Pharmacy
2019;26(14):1665-1669
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the feasibility and dosimetric characteristics of using dual-arc volumetric modulated arc therapy and multiple partial-arc VMAT for T3 lung cancer.
Methods:From June 2016 to May 2018, thirteen lung cancer patients with large planning target volume were replanned with dual full arcs VMAT(F-VMAT) and six partial-arc s VMAT(P-VMAT)on RayStation v4.5 RayArc function.PTV volume median was 550.9cm3(ranged 402.2-834.8cm3) and to a prescribed dose of 60 Gy in 30 fractions.Equivalent target coverage was required for all plans, and clinical goals were evaluated using various dose-volume metrics.These included PTV dose conformity, mean lung/heart dose, lung V5, V10, V20, V30, heart V30 and V40, and Dmax of spinal canal.The total monitor units (MUs) were also examined.
Results:All VMAT plans satisfied the treatment criteria.F-VMAT achieved better homogeneity index(HI) and MUs than P-VMRT(t=-3.904, P=0.002), and the conformal number(CN) of tumor volumes was likely clinically indistinguishable.However, F-VMAT significantly reduced lung V5, V10 and mean lung dose[V5: (51.31±5.36)% vs.(43.44±5.28)%, t=6.908, P=0.00; V10: (38.34±3.26)% vs.(34.05±3.74)%, t=4.632, P=0.001; Dmean: (1 449±117.19)cGy vs.(1 375.38±148.98)cGy, t=4.93, P=0.00], and heart dosimetric parameters were also observed in favor of P-VMRT[V30: (20.6±10.4)% vs.(16.4±8.9)%, t=3.822, P=0.02; V40: (14.6±7.5)% vs.(11.88±7.1)%, t=3.096, P=0.009; Dmean: (1 442.9±651.2)cGy vs.(1 263.5±605.6)cGy, t=3.986, P=0.02], and there were no statistically significant differences in lung V20, V30 and spinal cord Dmax between the two groups(all P>0.05).
Conclusion:VMAT is an effective treatment for stage T3 lung cancer patients.The primary advantage of P-VMAT was the reduction in low dose area and decreased risk of symptomatic radioactive lung injury.It may be a priority for pulmonary malignancy patients with the large planning target volume.
