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目的:控讨颈段胸上段食管癌T形野照射的最佳放疗模式。方法:26例颈段胸上段食管癌T形野照射的患者采用瓦里安Eclipse三维治疗计划系统(3D-TPS)对3种照射技术即:调强放疗(IMRT)、三维适形放疗(3D-CRT)和常规放疗(Con-RT)进行放射治疗计划设计。规定处方剂量54 Gy,95%等剂量线涵盖95%PTV(计划靶体积)。Con-RT利用3D-TPS模拟X线模拟机定位设计,等中心照射,前后T形野36 Gy,双侧水平野18 Gy,均用剂量体积直方图(DVH)分析PTV靶区各项参数和肺及脊髓受照体积和剂量。结果:(1)PTV靶区等剂量线、剂量不均匀指数(HI)和适形指数(CI)3种照射技术比较IMRT优于3D-CRT。3D-CRT优于Con-RT(P=0.000)(2)肺和脊髓受照体积和剂量3种照射技术比较IMRT优于Con-RT和3D-CRT虽然某些参数Con-RT稍优于3D-CRT,但大部分参数比较差异无统计学差异。(3)调强技术野数的参数比较,PTV、肺和脊髓的各项参数中,5野,7野和9野大部分参数优于3野,7野与9野比较差异均无统计学意义(P=0.244～0.947)。结论:IMRT技术是颈段胸上段食管癌T形野照射最佳选择,它与其他照射技术相比具有明显剂量学优势,以7野和9野IMRT较适宜。
OBJECTIVE: To investigate the optimal radiotherapy mode for T-field irradiation of the upper thoracic esophageal carcinoma of the neck. Methods: Twenty-six patients with esophageal T-field radiation from the upper thoracic segment underwent 3-dimensional Irradiation (IMRT), 3-D conformal radiotherapy -CRT) and conventional radiotherapy (Con-RT) for radiotherapy planning. Prescribing a prescribed dose of 54 Gy, the 95% isodose line covers 95% of the PTV (planned target volume). Con-RT using 3D-TPS simulation X-ray simulator positioning design, such as center irradiation, before and after the T-shaped field 36 Gy, bilateral horizontal field 18 Gy, dose-volume histogram (DVH) Lung and spinal cord volume and dose of exposure. Results: (1) IMRT was superior to 3D-CRT in three different irradiation techniques: isodose dose line, dose unevenness index (HI) and conformal index (CI) 3D-CRT was superior to Con-RT (P = 0.000) (2) Pulmonary and spinal irradiation volumes and doses compared to the three irradiation techniques IMRT better than Con-RT and 3D-CRT Although some parameters Con-RT slightly better than 3D -CRT, but most of the parameters were no significant difference. (3) Compared with the parameters of the field intensity augmentation technique, most of the parameters of PTV, lung and spinal cord were better than 3 field in 5 field, 7 field and 9 field, and no statistical difference was found in 7 field and 9 field Significance (P = 0.244 ~ 0.947). CONCLUSION: IMRT is the best choice for T-field irradiation of esophageal carcinoma of the upper thoracic segment. Compared with other irradiation techniques, IMRT has obvious dosimetric advantage. It is more suitable for 7-field and 9-field IMRT.