论文部分内容阅读
目的:分析宫颈癌患者调强放疗（intensity-modulated radiotherapy，IMRT）中不同的治疗直线加速器存在的系统误差与随机误差。方法:选择2019年10月至2021年11月在中山大学肿瘤防治中心Varian Vital_Beam加速器和Elekta Versa_HD加速器接受IMRT的宫颈癌患者320例，年龄32~75岁。每例患者在放疗计划设计完成后，按照治疗计划的移床参数进行X线模拟定位机复位验证，治疗实施时，使用锥形束CT（cone beam CT，CBCT）进行体位验证，共960次CBCT摆位误差数据。记录并观察CBCT校准后的体位误差数据并分别进行配对n t检验分析。n 结果:Varian Vital_Beam和Elekta Versa_HD直线加速器在头脚SI、左右LR、前后AP平移方向的摆位误差分别为（0.00±0.32）cm、（0.00±0.25）cm、（0.04±0.24）cm和（0.08±0.40）cm、（0.02±0.33）cm、（0.04±0.25）cm，头脚SI与前后AP两个方向差异均有统计学意义（均n P0.05）。Varian Vital_Beam和Elekta Versa_HD直线加速器在冠状RTN、矢状Pitch、横断Roll旋转方向的摆位误差分别为（-0.12±1.00）°、（0.81±1.33）°、（-0.32±0.64）°和（0.24±0.73）°、（0.28±1.64）°、（-0.01±0.80）°，差异均有统计学意义（均n P<0.05）。总的系统误差：Varian Vital_Beam各方向为头脚SI 0.29 cm、左右LR 0.22 cm、前后AP 0.22 cm、冠状RTN 0.81°、矢状Pitch 1.46°、横断Roll 0.63°；Elekta Versa_HD各方向为头脚SI 0.37 cm、左右LR 0.30 cm、前后AP 0.23 cm、冠状RTN 0.69°、矢状Pitch 1.44°、横断Roll 0.72°。总的随机误差：Varian Vital_Beam各方向为头脚SI 0.23 cm、左右LR 0.18 cm、前后AP 0.14 cm、冠状RTN 0.98°、矢状Pitch 0.87°、横断Roll 0.55°；Elekta Versa_HD各方向为头脚SI 0.28 cm、左右LR 0.23 cm、前后AP 0.15 cm、冠状RTN 0.54°、矢状Pitch 1.02°、横断Roll 0.56°。n 结论:不同放疗设备存在的系统误差有所差异，在头脚SI、左右LR、前后AP、横断Roll方向的分析中，Varian Vital_Beam的系统误差小于Elekta Versa_HD的系统误差；而冠状RTN、矢状Pitch旋转方向的系统误差大于Elekta Versa_HD的系统误差。“,”Objective:To analyze the systematic and random errors of different treatment linear accelerators in intensity-modulated radiotherapy (IMRT) for patients with cervical cancer.Methods:From October 2019 to November 2021, 320 cervical cancer patients who were 32-75 years old and received IMRT with Varian Vital_Beam accelerator and Elekta Versa_HD accelerator in Sun Yat-sen University Cancer Center were selected. After the design of the radiotherapy plan was completed, we performed the X-ray simulation positioning machine reset verification according to the bed moving parameters of the treatment plan for each patient, and used the cone beam CT (CBCT) for body position verification during the treatment, including 960 CBCT positioning error data. The body position error data after CBCT calibration were recorded and analyzed by paired n t-test.n Results:The positioning errors of the Varian Vital_Beam and Elekta Versa_HD linear accelerators in the superior-inferior (SI), left-right (LR), and anterior-post (AP) translation directions were (0.00±0.32) cm, (0.00±0.25) cm, (0.04±0.24) cm and (0.08±0.40) cm, (0.02±0.33) cm, (0.04±0.25) cm; there were statistically significant differences in the SI and AP directions (both n P0.05). The positioning errors of the Varian Vital_Beam and Elekta Versa_HD linear accelerators in the RTN, Pitch, and Roll rotation directions were (0.12±1.00)°, (0.81±1.33)°, (0.32±0.64)° and (0.24±0.73)°, (0.28±1.64)°, (0.01±0.80)°; there were statistically significant differences (alln P<0.05). The total systematic error errors of Varian Vital_Beam linear accelerator in the SI, LR, AP, RTN, Pitch, and Roll directions were 0.29 cm, 0.22 cm, 0.22 cm, 0.81°, 1.46°, and 0.63°; the total systematic error errors of Elekta Versa_HD linear accelerator in the SI, LR, AP, RTN, Pitch, and Roll directions were 0.37 cm, 0.30 cm, 0.23 cm, 0.69°, 1.44°, and 0.72°. The total random errors of Varian Vital_Beam linear accelerator in the SI, LR, AP, RTN, Pitch, and Roll directions were 0.23 cm, 0.18 cm, 0.14 cm, 0.98°, 0.87°, and 0.55°; the total random errors of Elekta Versa_HD linear accelerator in the SI, LR, AP, RTN, Pitch, and Roll directions were 0.28 cm, 0.23 cm, 0.15 cm, 0.54°, 1.02°, and 0.56°.n Conclusions:The systematic errors of different radiotherapy equipment are different. In the SI, LR, AP, and Roll directions, the systematic error of Varian Vital_Beam is smaller than that of Elekta Versa_HD; while in the RTN and Pitch directions, the systematic error of Varian Vital_Beam is greater than that of Elekta Versa_HD.