Helical tomotherapy optimized planning parameters for nasopharyngeal cancer

13th South-East Asian Congress of Medical Physics 2015

物理学;医药卫生

Yawichai, K.^1 ; Chitapanarux, I.^1 ; Wanwilairat, S.^1

Department of Therapeutic Radiology and Oncology, Faculty of Medicine, Chiang Mai University, Thailand^1

关键词: Helical tomotherapy;    Modulation factors;    Nasopharyngeal cancer;    Optimization parameter;    Optimization procedures;    Optimized parameter;    Optimized planning;    Treatment plans;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/694/1/012002/pdf
DOI  :  10.1088/1742-6596/694/1/012002

学科分类：卫生学

来源: IOP

【 摘 要 】

Helical TomoTherapy(HT) planning depends on optimize parameters including field width (FW), pitch factor (PF) and modulation factor (MF). These optimize parameters are effect to quality of plans and treatment time. The aim of this study was to find the optimized parameters which compromise between plan quality and treatment times. Six nasopharyngeal cancer patients were used. For each patient data set, 18 treatment plans consisted of different optimize parameters combination (FW=5.0, 2.5, 1.0 cm; PF=0.43, 0.287, 0.215; MF2.0, 3.0) were created. The identical optimization procedure followed ICRU83 recommendations. The average D50 of both parotid glands and treatment times per fraction were compared for all plans. The study show treatment plan with FW1.0 cm showed the lowest average D50 of both parotid glands. The treatment time increased inversely to FW. The FW1.0 cm the average treatment time was 4 times longer than FW5.0 cm. PF was very little influence on the average D50 of both parotid glands. Finally, MF increased from 2.0 to 3.0 the average D50 of both parotid glands was slightly decreased. However, the average treatment time was increased 22.28%. For routine nasopharyngeal cancer patients with HT, we suggest the planning optimization parameters consist of FW=5.0 cm, PF=0.43 and MF=2.0.