Analysis of pathogenic factors of radiation encephalopathy after radiotherapy for nasopharyngeal carcinoma

Ａｎａｌｙｓｉｓｏｆｐａｔｈｏｇｅｎｉｃｆａｃｔｏｒｓｏｆｒａｄｉａｔｉｏｎｅｎｃｅｐｈａｌｏｐａｔｈｙａｆｔｅｒｒａｄｉｏｔｈｅｒａｐｙｆｏｒｎａｓｏｐｈａｒｙｎｇｅａｌｃａｒｃｉｎｏｍａ￥ＺｈａｎｇＸｕｅｌｉｎ（张雪林）；ＹａｎＷｅｉｐｉｎｇ（阎...

Analysis of pathogenic factors of radiation encephalopathy after radiotherapy for nasopharyngeal carcinoma

The authors investigated 242 patients after radiotherapy for nasopharyngeal carcinoma (NC).Of whom 84 developed radiation encephalopathy (REP), the incidence rate(IR) of REP was 34.7%.In various factors associated with REP, the irradiation source, total radiotherapeutic dose (TRD) and fractionation were the most important ones. The IR of REP increased with the increase of TRD. When the TRD was above 71 Gy, the increase of the IR of REP was quite remarkable (P<0.01). The incidence rate was higher in the combination of 60Co with linear accelerator than in either 60Co or accelerator. Therefore, particularly great attention must be paid to prevention of REP. The most effective measures for preventing REP are to use magnetic resonance imaging (MRI) and computer tomography (CT) to localize REP in order to reduce the field of irradiation and to change the angle of irradiation for avoidance of direct irradiation of the brain, and to control the TRD and fractionation strictly. The authors developed a figure for fractionation, which may be acted as reference for clinical application.