【摘要】 探讨影响气腔界面剂量建成与跌落效应的参量：气腔尺寸、射野大小、气腔前方组织厚度。并讨论放疗实践中所涉及的气腔问题，如鼻咽癌及喉癌的放疗。结果表明，简便实用的方法是适当增大射野以降低气腔效应直至忽略其影响。更多还原

【Abstract】 AbstractSome parameters(size of air cavity,size of radiation field,thickness of the tissue in front ofthe air cavity)which could influence the dose build up or build down at the boundary surface ofthe air cavity of the tissue in the MV radiation field wero measurcd.And some problems about aircavity were discussed for certain radiation therapy practices,e..nasopharyngeal cancer andlaryngeal cancer. The aurthors believe that a simplc and practical method is to properly increasethe slze of the radiation field to reduce the effect of air cavity,even to the degree of beingneglegible.更多还原