应用ICRU83号^（[1]）报告评价鼻咽癌两种定位方法在常规放疗中的优劣

目的：用ICRU83号[1]报告,比较X线模拟和CT模拟采集图像对常规放疗的鼻咽癌靶区及各危及器官的剂量贡献。方法：选择鼻咽癌患者10例,分别应用X线模拟采集DR图像和CT模拟采集断层图像,计划系统评价危及器官的受照剂量及相关受照剂量体积。结果：在临床靶区1（clinical target volume,CTV1）、临床靶区2（CTV2）CT图像勾画的低剂量区高于DR图像,而治疗区体积小于X线图像（P〈0.05）。危及器官受照剂量方面,垂体、视交叉、视神经、颌下腺、晶体、颞叶、上颌窦、口腔方面的受量和受照体积,X线图像高于CT图像有统计学意义（P〈0.05）,脑干、脊髓、腮腺、颞颌关节、下颌骨和耳蜗两者之间无统计学差异。结论：CT图像能提高鼻咽癌靶区剂量,减小了治疗区的体积,较X线图像能有效地减少周围危险器官的受照剂量和受照体积,应能减轻放射副反应。

Use ICRU83 Report to Evaluate the Advantages and Disadvantages of Two Localization Methods for Nasopharyngeal Carcinoma in Traditional 2D Radiotherapy

Objective: We use ICRU 83 report to compare the effectiveness of two image acquiring methods: X-ray simulator and CT simulation system,and the dose distributions in the tumor target regions and adjacent organs at risk of each system in nasopharyngeal carcinoma(NPC.Methods: X-ray simulator and CT simulation system were applied to a cohort of 10 patients,DR and CT images were gained.The doses of target volume or related volume were determined by using a treatment planning system(TPS).Results: CT images delineated larger clinical target volume 1(CTV1 and clinical target volume 2(CTV2),and smaller target volume compared to DR images(P< 0.05).DR images assigned significant larger volume and higher dose to the following organs at risk compare to CT images: pituitary,optic chiasm,optic nerves,submandibular glands,lens,temporal lobe,maxillary sinus and oral cavity.No remarkable volume and dose differences between two imaging systems were observed in these following organs at risk: brain stem,spinal cord,parotids,temporomandibuler joint,mandibla and cochlea.Conclusions: Compared to DR images,CT simulation system increases target volume dose and decreases volume of target.Moreover,CT images reduce the dose and volume of surrounding organs at risk,which can prevent the occurrence of side effects in radiotherapy.