Effect of minimum segment width on the quality of volumetric modulated arc therapy plan for lung cancer(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2020年第3期
- Page:
- 277-281
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Effect of minimum segment width on the quality of volumetric modulated arc therapy plan for lung cancer
- Author(s):
- WEI Min1; NIU Zhenyang2; LIU Lingling3; LI Bingbing3; FEI Zhenle1; WANG Lei2; LI Zhijie2
- 1. School of Biomedical Engineering, Anhui Medical University, Hefei 230032, China; 2. Department of Radiation Oncology, No.901 Hospital of PLA, Hefei 230031, China; 3. Cancer Hospital, Chinese Academy of Sciences, Hefei 230031, China
- Keywords:
- Keywords: lung cancer; volumetric modulated arc therapy; minimum segment width; plan quality
- PACS:
- R811.1；R734.2
- DOI:
- DOI:10.3969/j.issn.1005-202X.2020.03.004
- Abstract:
- Abstract: Objective To explore the effect of the minimum segment width on the quality of volumetric modulated arc therapy (VMAT) plan for lung cancer. Methods Twelve patients with pathologically confirmed lung cancer were enrolled in the study. The prescription dose of planning target volume (PTV) was 60 Gy/30 fractions. Monaco treatment planning system was used to design full-arc VMAT plans, with a calculation mesh of 0.3 cm, 6 MV X-rays, and a maximum control points of 200 per arc. The statistical uncertainty of each calculation was 1%. The minimum segment width was selected to be 0.5, 0.7, 1.0, 1.2 and 1.5 cm, respectively. The plan with a minimum segment width of 1.0 cm was taken as a reference plan, and then compared with the other plans for analyzing the variation of dosimetric indexes with the minimum segment width. Results When the minimum segment width was increased to 1.2 and 1.5 cm, the Dmean and D2 of target areas varied significantly (P?0.05). There were statistical differences in the conformity index between the reference plan and the plan with the minimum segment width of 1.5 cm (Z=-2.694, P?0.05), and in the target coverage between the reference plan and the plans with the minimum segment width of 0.5, 0.7, 1.2 and 1.5 cm (Z=-2.904, -3.061, -2.747, -2.941, P?0.05). The average monitor units in the VMAT plan with a minimum segment width of 1.0 cm was 684.4 MU, and that in the other plans with a minimum segment width of 0.5, 0.7, 1.2 and 1.5 cm was 972.8, 763.8, 660.1 and 665.3 MU, respectively. With the increase of minimum segment width, the number of control point was decreased. Conclusion For the lung cancer VMAT plans designed by Monaco planning system, the quality of the VMAT plan with a minimum segment width of 1.0 cm is better. Adjusting the minimum segment width of VMAT plan can not only greatly reduce monitor units and improve delivery efficiency, but also improve the comfort of patients.
Last Update: 2020-04-02