Abstract:During radiation for head and neck cancers, part of parotids are contained in planning target volume(PTV), which lead to parotids receiving radiation as the same as PTV. Radiation for head and neck cancers will influence the parotids. In the period of radiation, many factors will influence parotids, such as age, primary parotid volume, V_10-40, weight and mean radiation dose et al. This factors will result in that the parotid volume reduces nearly 50% and moves toward the middle line of the body. As a result, the real dose of the parotid receiving is higher than prescription dose. The excretion function of the parotid will be severely damaged after radiation, which will lead to xerostomia and influence the quality of patients life.

Key words: font-size: 12pt,mso-font-kerning: 1.0pt,mso-ansi-language: EN-US,mso-fareast-language: ZH-CN,mso-bidi-language: AR-SA,mso-fareast-font-family: 宋体" lang="EN-US">Head and neck neoplasms,Radiotherapy,Parotid gland