摘要
目的:测量体部伽马(γ)刀换源后各项剂量学指标。方法:用PTW电离室剂量仪、球模测量焦点剂量率,Φ15、Φ30和Φ50 mm准直器输出因子,进退床过程中的附加剂量;用智能γ辐射仪、自显影胶片EBT2、焦点测量棒以及球模检测机械中心与辐射中心偏差、辐射野半高宽及半影、焦点综合定位误差、治疗计划综合剂量校准及非治疗状态下的杂散辐射。结果:机械中心与辐射中心偏差0.18 mm,焦点剂量率2.786 Gy/min,各准直器输出因子分别为0.633 5、0.922 5和1,进退床附加剂量<2%,Φ15、Φ30和Φ50 mm半影小于12 mm,半高宽与标定值差别分别在2、3和5 mm内,综合定位误差<2.5 mm,各准直器单靶点剂量计划值与实测值误差<5%,非治疗状态下的杂散辐射满足防护要求。结论:经换源调试后各项物理学参数符合国家标准,满足临床需要。
Objective To measure the dosimetry parameters of body gamma-knife after changing the Co60 sou rce.Methods Ionization chamber and spherical model were used to measure the focus dose rate, Φ15, Φ30 and Φ50 mm collimator output factors, and additional dose during the process of radiation therapy. Smart gamma radiometer, autoradiography films EBT2, focus detecting stick and spherical model were applied to measuring the deviation between the mechanical center and the center of radiation field, the full width at half maximum（FWHM） of radiation field, radiation penumbra, integrated positioning error of the radiation focus, the dosage calibration of the TPS and the stray radiation without treatment. Results The deviation between the mechanical center and the center of radiation field was 0.18 mm, the focus dose rate was 2.786 Gy/min, and Φ15, Φ30 and Φ50 mm collimator output factors were 0.633 5, 0.922 5 and 1 respectively. Additional dose during the process of radiation therapy was less than 2%, and radiation penumbra was less than12 mm and the deviations of FWHM of Φ15, Φ30 and Φ50 mm collimators were within 2, 3 and 5 mm respectively. Integrated positioning error of the radiation focus was less than 2.5 mm, the dosage calibration of the treatment was less than 5% and the stray radiation without treatment met the national standard. Conclusion The dosimetry parameters of body gamma-knife after changing the Co60 source meet the national standards and the clinical needs.
出处
《医疗卫生装备》
CAS
2015年第10期91-93,105,共4页
Chinese Medical Equipment Journal
关键词
体部伽马刀
质量保证
质量控制
中心偏差
焦点剂量率
杂散辐射
body gamma-knife
quality assurance
quality control
center deviation
focus dose rate
stray radiation
