改进鼻咽癌放射治疗技术的研究─—（Ⅰ）靶区剂量分布

A STUDY ON IMPROVING THE TREATMENT TECHNIQUE OF THE RADIOTHERAPY IN NASOPHARYNGEAL CARCINOMA PART I:THE DOSE DISTRIBUSION OF TARGET VOLUME

通过治疗计划系统（ＴＰＳ）对综合面颈联合野、面颈分野（采用低熔点铅挡块，等中心照射）和常规单纯面颈分野两种鼻咽癌的放射治疗方案进行靶区剂量分布的测量。结果显示改进治疗方案与常规单纯面颈分野方法比较具有以下优点：１．靶区都受到较高均匀的照射；２．保护口腔、喉腔，颞顶叶和脑干受照射的体积大大减少；３．避免面颈分野在头颈交接处产生“热点”或“冷点”；４．体位不变，剂量计算较准确；５鼻前野照射时，颅底位于射野中心；其不足之处是与常规面颈分野相比脊髓量偏高，但仍在中枢神经系统可耐受的剂量水平以下。

To survey the target volume dose distribtition of two trentnlein plan, one of wNch is face-necklateral fields combined with spliting face-neck lateral fields, another spliting face-neck lateral fields alone, byulitilizing treatment plaiming system(TPS). The results showed that the former has the following advan-tages comparing with the latter:1.All target volume received higher and more uniform doses;2. Protection of the oral cavity and the throat, greatly reducing the irraddiated volume of parietal,tem-poral lobe and stem of the brain;3.Avoiding “hot spot”and/or“cool spot”in the border of the irradiation fields of the head and neck;4. Keeping the irradiated position unchange, so ats to calculate the dose accuately;5.The base of the skull lying in the center of the irradiated field while using anterior field. Its shortcoming is that there is higher dose in the spinal cord,but which is still under the tolerated lev-el of the centralnevous svstem.