第一,设计和评价照射野必须根据肿瘤(包括原发灶和经常转移的区域淋巴结)的分布及邻近关键脏器(或结构)的位置。由于CT能作直观形象和三维的显示。所以它是当前量好的设计和评价照射野的工具。作者应用CT不仅确定了鼻啊癌的主要淋巴结,包括只有CT才能在活体清楚显示的咽后淋巴结,颈深淋巴结及脊付淋巴结的位置与它们的体表投影,而且发现这些淋巴结与鼻咽原发肿瘤在侧面的体表投影,互相 First, the design and evaluation of the irradiation field must be based on the distribution of tumors (including primary and often metastatic regional lymph nodes) and the location of adjacent vital organs (or structures). Because CT can be visualized and three-dimensional display. So it is a good tool for designing and evaluating radiation fields. The authors used CT to determine not only the main lymph nodes of nasal adenomas, but also CT only to clearly show the location of the retropharyngeal lymph nodes, deep cervical lymph nodes, and spinal lymph nodes with their surface projections in vivo, and to find these lymph nodes and nasopharyngeal Tumors on the side of the body surface projection, mutual