^18FDG PET-CT双时相显像在非小细胞肺癌肺门纵隔淋巴结累及野放疗靶区勾画中的价值

Value of dual-time-point ^18FDG PET-CT imaging on involved-field radiotherapy for hilar and mediastinal metastatic lymph nodes in non-small cell lung cancer

目的探讨^18FDG PET-CT双时相显像在非小细胞肺癌（NSCLC）肺门纵隔淋巴结累及野放疗靶区勾画中的价值。方法选取行手术治疗的NSCLC患者54例，术前3～5d内行^18FDG PET-CT常规全身显像和胸部延迟显像，以术后病理诊断结果为标准，比较根据常规显像和双时相显像结果勾画的淋巴结累及野放疗靶区的不同。结果肺门淋巴结靶区39％患者GTV常规与GTV病理一致，57％患者GTV双时相与GTV病理一致；△GTV1（GTV常规-GTV病理）=32．64cm^3，△GTV2（GTV双时相-GTV病理）=22．57cm^3，后者比前者变化少（u=519．00，P=0．023）。纵隔淋巴结靶区56％患者GTV常规与GTV病理一致，67％患者GTV双时相与GTV病理一致；△GTV1=22．85cm^3，△GTV2=20．95cm^3，后者与前者变化相似（u=397．50，P=0．616）。结论根据^18FDG PET-CT双时相显像结果勾画的NSCLC肺门纵隔转移性淋巴结靶区更接近于根据病理结果勾画的靶区，双时相显像较常规显像能更好地指导淋巴结累及野靶区的勾画。

Objective To discuss the value of dual-time-point ^18FDG PET-CT imaging on involvedfield radiotherapy for hilar and mediastinal metastatic lymph nodes in patients with non-small cell lung cancer （NSCLC）. Methods Fifty-four patients with NSCLC were included in this analysis, including 34 men and 20 women with mean age of 59（34-76） years. Two sequential PET-CT scans given 3-5 days before surgery were standard single-time-point imaging for the whole body and delayed imaging for the thorax. The pathologic data were used as golden standard to determine the difference between the standard single-time-point and dual-time-point FET-CT imaging in the definition of gross target volume （GTV） of involved-field radiotherapy for metastatic lymph nodes. Results For hilar metastatic lymph nodes, the GTV defined by single-time-point imaging was consistent with pathologic GTV in 21 patients（39% ） ,comparing with 31 patients（57% ） by dual-time-point imaging. Using pathologic data as golden standard, GTV alteration defined by single-time-point imaging had statisticaly significant difference comparing with that defined by dual-time-point imaging（ u = 519.00 ,P = 0.023 ）. For mediastinal metastatic lymph nodes, the GTV defined by single-time-point imaging was consistent with pathologic GTV in 30 patients（56% ） ,comparing with 36 patients（67% ） by dual-time-point imaging. Using pathologic data as golden standard, GTV alteration defined by single-time-point imaging had no statisticaly significant difference comparing with that defined by dual-time-point imaging（ u = 397.50,P = 0.616）. Conclusions For patients with NSCLC receiving involved-field radiotherapy, GTV definition for hilar and mediastinal metastatic lymph nodes by dual-time-point imaging is more consistent with that by pathologic data. Dual-time-point imaging has a larger value in terms of target delineation for hilar and mediastinal metastatic lymph nodes.