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[目的]对面颈联合野为基础的鼻咽癌外照射治疗方案进行剂量学评价。[方法]采用ACQSim &ACQPlan(CT模拟及三维计划系统) ,根据不同的外照射方案 ,评价不同层面的三维剂量分布及正常组织的DVH。[结果]①各种方案的90%～100%的等剂量曲线包纳鼻咽原发灶、颅底、咽旁间隙、口咽及颈部区域 ,剂量分布均匀 ,脑干及上颈脊平均剂量分别为12.2Gy～19Gy及46.4Gy～49.3Gy。②垂体保护或将上界定于蝶窦顶 ,垂体平均剂量由60.3Gy分别下降至29.2Gy及14.7Gy;加用鼻前野 ,减少了颞颌关节、中耳、腮腺的受量。③射野后界定于斜坡上、下端后0.75cm及1.5cm ,95%的等剂量曲线包纳整个颅底 ,剂量达66.5Gy～70Gy。④采用全程面颈联合野 +β 线照射颈后三角野方案 ,咽旁间隙、口咽及上颈部分布一个100%～105 %的等剂量曲线。[结论]以面颈联合野为基础的各种鼻咽癌外照射治疗方案满足肿瘤靶区照射的剂量学要求 ,但是 ,正常组织如颞颌关节、中耳、腮腺、视交叉亦受到不同程度高剂量的照射 ,3D CRT及IMRT是鼻咽癌放射治疗发展的趋势 ,在设备完善及有良好QC和QA肿瘤中心 ,可开展此技术的运用。针对病人不同的临床分期 ,提出选择不同鼻咽癌外照射治疗方案的原则。
[Objective] To evaluate the dosimetry of nasopharyngeal carcinoma external irradiation treatment based on facial and cervical joint field. [Methods] The three-dimensional dose distribution and DVH of normal tissues at different levels were evaluated by ACQSim & ACQPlan (CT simulation and 3D planning system) according to different external irradiation schemes. [Results] ① The isodose curves of 90% ~ 100% of various regimens contained the nasopharyngeal primary tumor, cranial base, parapharyngeal space, oropharynx and neck region with uniform dose distribution, average brain stem and upper cervical ridge Dose were 12.2Gy ~ 19Gy and 46.4Gy ~ 49.3Gy. ② pituitary protection or defined on the top of the sphenoid sinus, the average dose of pituitary decreased from 60.3Gy to 29.2Gy and 14.7Gy; plus nasal anterior field, reducing the temporomandibular joint, middle ear, parotid gland by the amount. ③ After the field is defined on the slopes, the lower end of 0.75cm and 1.5cm, 95% of the isodose curve contains the entire skull base, a dose of 66.5Gy ~ 70Gy. ④ using the full face and neck joint field + β line irradiation of the triangular program after the neck, parapharyngeal space, oropharynx and the upper part of the cloth a 100% to 105% of the isodose curve. [Conclusion] Various nasopharyngeal carcinoma external irradiation treatment plans based on the facial and cervical joint field meet the dosimetry requirements of tumor target irradiation. However, normal tissues such as temporomandibular joint, middle ear, parotid gland and optic chiasm are also affected to varying degrees High-dose irradiation, 3D CRT and IMRT are the development of radiation therapy for nasopharyngeal carcinoma. This technique can be used in well-equipped and well-established QC and QA tumor centers. According to the different clinical stages of patients, the principle of selecting different nasopharyngeal carcinoma external irradiation treatment programs was proposed.