The primary research for the influence of immobilization baseplate of carbon fiber on dose distribution of radiation field of radiotherapy
10.3969/J.ISSN.1672-8270.2018.01.007
- VernacularTitle:碳纤维固定底板对放射治疗射野剂量分布影响的初步研究
- Author:
Zheng-Lu BAI
1
;
Fei-Yue SHI
;
Wei QIN
;
Hong-Bing JIANG
Author Information
1. 南京医科大学附属南京医院(南京市第一医院)医疗设备处 江苏 南京 210006
- Keywords:
Carbon fiber;
Immobilization baseplate;
Dose attenuation;
Gamma passing rate;
MatriXX;
Intensity modulated;
Medical linear accelerator
- From:
China Medical Equipment
2018;15(1):22-25
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the attenuation of immobilization baseplate of carbon fiber for ray and the change of dose verification results for enhanced radiation field of MatriXX. And to primarily research the influence of this immobilization baseplate for the dose distribution of radiation field of radiotherapy.Methods: 20 patients with cervical cancer were enrolled in the research. The angle of gantry was 180°in the enhanced plan of immobilization field, and the corresponding verification plans were designed. When the verification plan was implemented on the Varian Clinac iX of accelerator, the two-dimensional ionization chamber array (MatriXX) was used to measure dose distributions of the plan. The immobilization baseplate of carbon fiber (ORFIT AIO) was used in the research. The situations of no baseplate (A group), one baseplate (B group), two baseplates (C group)and three baseplates (D group)between the handpiece of accelerator and Matri XX were researched, respectively. The data of the 4 groups were obtained by using software (OminiPro I'mRT), and the largest dose point and passing rate of Gamma in plane of radiation field were counted and analyzed.Results: Compared with A group, the average attenuation factors for ray on the largest dose point of B, C and D group in the plane of radiation field were (1.73±0.11)％, (3.44±0.36)％, and (5.48±0.44)％, respectively. The passing rates of Gamma in the 4 groups were (94.87±2.31)％, (99.18±0.61)％, (99.79±0.27)％ and (96.24±1.99)％, respectively. And the differences of passing rate between each group and A group were statistical significance (t=9.788,t=9.261,t=2.256,P<0.05).Conclusion:The immobilization baseplate of carbon fiber has influence for the attenuation of high-energy X-rays and it can affect the dose distribution of radiation field which has passed baseplate in some degrees. And when physicists calculates the dose, they should consider the effect of immobilization baseplate of carbon fiber for dose distribution of radiation field.
