一、体外放疗常规中存在的不足1．不符合靶区全照射原则近年来对包括咽旁照射设计进行了不少讨论，常规耳前野不能保证茎突后区获得足够剂量，采用耳后野（向前倾斜）补充茎后区＿眼下野补充鼻腔或茎突前区的方法都会将靶区分割开来照射，而且咽分间隙上自颅底、下连颌下间隙， First, the lack of conventional radiotherapy in vitro 1. Inconsistent with the principle of full irradiation target In recent years, including the design of the parapharyngeal irradiation for a lot of discussion, the conventional ear field can not guarantee the posterior segment of the styloid process to obtain sufficient dose, the use of the posterior uterus (forward tilt) to supplement the posterior stem area Nasal or styloid process to supplement the front of the target area will be split to irradiation, but also pharyngeal gap from the skull base, under the submandibular space,