The necessity of inclusion of a virtual treatment couch involved in the XiO treatment planning system
10.3760/cma.j.issn.0254-5098.2018.01.005
- VernacularTitle:在XiO计划系统中构建虚拟治疗床的必要性评估
- Author:
Hongbo GUO
1
;
Bingbing LI
;
Zhenle FEI
;
Lingling LIU
;
Hongzhi WANG
Author Information
1. 230026 合肥,中国科学技术大学;中国科学院合肥物质科学研究院医学物理与技术中心医学物理与技术安徽省重点实验室
- Keywords:
Virtual treatment couch;
XiO treatment planning system;
Relative electron density;
Octavius 4D phantom
- From:
Chinese Journal of Radiological Medicine and Protection
2018;38(1):21-25
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the dosimetric effect of carbon fiber couch through virtual simulation in the XiO treatment planning system (TPS).Methods A treatment couch model of iBEAM evo Extension 650 was scanned with a big bore spiral CT and its contour was stored in the XiO TPS.The attenuation coefficient of couch was obtained by measuring the attenuated dose with and without a solid water phantom on the couch at different gantry angles (100°-180°).The optimal relative electron density (RED) values of the carbon fiber (CF) cover and foam core (FC) were adjusted according to the comparison between measured and simulated attenuation dose.The effects of the couch in the TPS on pass rate were evaluated by Octavius 4D phantom with 10 cases with lung cancer.Results The optimal RED values of CF and FC were 0.75 and 0.10 g/cm3,respectively.The measured attenuation error was the maximal at gantry angle of 120° (4.84％) without the treatment couch in the TPS.The average measured attenuation errors without the couch in the TPS dropped significantly from (2.54 ± 1.48) ％ to (-0.04 ± 0.36) ％ after inclusion of the treatment couch during dose calculation (Z =-3.621,P ＜ 0.05).The three-dimensional dose verification γ pass rate (3 mm/3％) without the couch increased significantly from (91.79± 1.25)％ to (94.74± 1.69)％ after inclusion of the couch in the dose calculation (t =6.027,P ＜ 0.05).Conclusions The effect of couch on the attenuation dose is significant.Inclusion of a virtual model of couch in XiO TPS can simulate the attenuation effect properly and improve the accuracy of dose calculation.
