非小细胞肺癌立体定向放疗的两种体位固定方式比较

目的探讨真空垫和热塑膜在肺癌立体定向放疗（SBRT）固定时的适用性。方法随机收集浙江省肿瘤医院胸部放疗科22例接受SBRT的周围型非小细胞肺癌患者,其中12例采用真空垫体位固定技术,余10例采用热塑膜体位固定技术,每次治疗前拍摄CBCT（cone-beam CT,锥形束CT）影像与治疗计划进行配准,配准前人工校对得出患者左右、上下、前后方向摆位误差,比较两组误差的大小。结果真空垫组三个方向上的摆位误差分别为（2.51±0.75）mm、（2.62±0.81）mm、（2.21±0.69）mm,热塑膜组三个方向上的摆位误差分别为（2.43±0.82）mm、（2.58±0.77）mm、（2.35±0.86）mm,两组摆位误差值均相近（P〉0.05）。在前后（Z轴）方向上热塑膜组线性误差〉3.5 mm的更多,差异有统计学意义（P〈0.05）。结论两种体位固定技术在肺癌SBRT中各有优劣,但均在可控范围内。相对来说真空垫提高了患者舒适性,更加适合年纪大、身体情况差、强迫体位的患者。

Comparison of fixations at two kinds of positions in non-small cell lung cancer stereotactic radiotherapy

Objective To explore the applicability of vacuum pad and thermoplastic film in fixation of stereotactic body radiotherapy（SBRT） of lung cancer. Methods A total of 22 cases of patients with peripheral non-small cell lung cancer（NSCLC） were randomly selected, who were undergone SBRT in Thoracic Radiotherapy Department of Zhejiang Cancer Hospital. Among them, 12 cases were given vacuum pad fixation, while the rest 10 cases were given thermoplastic film fixation. CBCT image was registered with the treatment scheme before every treatment. Setup error in every direction was obtained by artificial proofreading before registration. The error of the two groups was compared. Results The setup errors on the three directions were（2.51±0.75）mm,（2.62±0.81）mm and（2.21±0.69）mm in vacuum pad group,while the setup errors on the three directions were（2.43±0.82）mm,（2.58±0.77）mm and（2.35±0.86）mm in thermoplastic film group. Setup errors of the two groups were similar（P〉0.05）. The linearity error of thermoplastic film group was more than 3.5 mm only along the anterior-posterior direction（Z axis）,and the difference was statistically different（P〈0.05）. Conclusion Two kinds of fixations both have advantages and disadvantages in SBRT of lung cancer,which are under control. Vacuum pad fixation can relatively increase the patient＇s comfort,which is more suitable for older patients with poor physical condition and compulsive postures.