中文摘要：

目的通过18F-脱氧葡萄糖正电子发射断层．x线计算机体层成像（18F-FDGPET．CT）最大标准化摄取值（SUVmax）在鼻咽癌放疗过程中的动态变化，探讨其早期评价鼻咽癌患者放疗过程的生物代谢反应的可能性。方法60例经病理确诊的初治鼻咽癌患者，于放疗前1周、放疗50Gy时、放疗结束时和放疗结束后1个月行18F—FDGPET—CT检查，分析SUVmax与病理类型的关系。结果随着放疗的进行，鼻咽原发灶的SUVmax逐渐下降（P〈0．001），放疗前、放疗50Gy时、放疗结束时和放疗结束后1个月的SUVmax分别为11．20±5．37、3．50±1．59、3．05±1．56和2．52±1．46。鼻咽原发灶中，非角化型未分化癌和非角化型低分化癌的放疗前SUVmax分别为12．35±5．79和9．35±4．19（P=0．038）；放疗50Gy时，ASUVmax分别为（67±19）％和（55±24）％（P=0．046）。结论在放疗早期采用18F—FDGPET．CT评价放疗敏感性是可能的，但还需结合长期随访结果进行分析。

英文摘要：

Objective The primary aim of this prospective study was to use serial ISF-FDG PET-CT imaging to evaluate the trend of the tumor＇s maximum standardized uptake value （SUVmax） during radiotherapy （RT） for patients with nasopharyngeal carcinoma （NPC）, and to explore the possibility of early evaluation of the tumor bio-metabolic response during radiotherapy. Methods Sixty patients with biopsyproven primary NPC were prospectively enrolled into the study. All patients underwent four 18F-FDG PET-CT scans ： one initial scan before RT/cisplatin based concurrent ehemoradiotherapy, at the point of 50 Gy during RT, the end of RT, and one month after RT, respectively. Tumor 18F-FDG uptake was analyzed aeording to the World Health Organization pathological type. Results There was a significant difference （ P 〈 0. 001 ） of the mean of SUVmax of the primary site among pretreatrnent （ 11.20 ±5.37 ） and posttreatment at the dose of 50 Gy （3.50± 1.59）, at the end of RT （3.05 ± 1.56） and one month after RT （2.52 ± 1.46）. There was also a significant difference （ P 〈 0. 001 ） of the mean of SUVrnax of neck node site. However, there was a significant difference of the SUVmax between histological WHO type lib and type Ⅱa in the primary site （P = 0. 046） [ （67 ± 19） % reduction at dose 50 Gy for type Ⅱb vs. （ 55±24） % for type Ⅱa ] but not in the lymph nodes. Conclusions Early PET scan during or right after RT instead of conventional 3 months interval after RT is indicated to evaluate the tumor response and to develop individualized adaptive radiotherapy in NPC. Our next study will attempt to demonstrate the results based on long-term follow-up data.