PET-CT对非小细胞肺癌精确放疗靶区勾画的影响

Impact of PET-CT imaging on gross target volumes in non-small-cell lung cancer

目的探讨正电子发射体层显像（PET）与CT同机融合图像（PET-CT）对非小细胞肺癌（NSCLC）大体肿瘤靶区（GTV）勾画的影响。方法选取46例具有典型影像表现的NSCLC患者的PET-CT资料，根据其影像学特点将所有病例分为3组，肺不张组16例，纵隔和（或）肺门淋巴结转移组18例，外周型单纯肺内病灶组12例。根据CT和PET-CT模拟勾画大体肿瘤靶区（G1VCT和GTVPET-CT），采用体积比较及重合程度评价靶区改变情况，并对比3组病例重合程度有无差别。结果肺不张组平均GTVCT为160．813cm3，平均GTVPET-CT为108．838cm3（t=13．592，P〈0．05）；淋巴结转移组平均GTVCT65．233cm3，平均GTVPET-CT84。367cm3（t=2．768，P〈0.05）；单纯肺内病灶组平均GTVPET-CT为21．7cm3，GTVPET-CT为19．6cm3，二者体积无差别（t=0．684，P〉0．05），1组病例重合度淋巴结转移组为0．561，肺不张组0．698，单纯病灶组0．740，经q检验显示差异有统计学意义（P〈0．05）。结论根据PET-CT和CT所勾画的靶区GTVPET-CT和GTVCT，在体积大小及重合程度上均存在不同程度差异，与单纯的CT图像相比，PET—CT勾画靶区更为精确；伴肺门和（或）纵隔淋巴结转移的患者使用PET—CT勾画靶区可获得更大受益，其次为肺不张，外周型单纯肺内病灶受益最小。

Objective To investigate the effect of lS F-fluoro-deoxy-2-glucose hybrid positron emission tomography images combined CT image（ 18F-FDG PET-CT）on gross target volumes in non-small-cell lung cancer （NSCLC）. Methods Forty six patients with pathological defined NSCLC were included in the study. All patients were divided into three groups according to image features： lymphatic metastasis group （ 18 cases）, atelectasis group（ 16 cases ）, solitary focus group （ 12 cases ）. The gross target volumes by CT and by PET-CT （GTVCT and GTVPET-CT ）were compared with volume differentials and coherence. We also compared the coherence among the three groups. Results The median GTVCT and median GTVPET-CT of atelectasis group was 160. 813 cm3 and 108. 838 cm3 （ t = 13. 592 ,P 〈 0.05 ）. The median GTVCT and median GTVPET-CT of lymphatic metastasis group was 65. 233 cm3 and 84. 367cm3 （ t = 2. 768, P 〈 0.05 ）. In the solitary focus group , median GTVCT was 21.7 cm3, and median GTVPET-CT was 19.6 cm3 （ t =0. 684, P 〉 0.05 ）. There was statistic difference in coherence among the three groups （lymphatic metastasis group 0. 561, atelectasis group 0. 698, solitary focus group 0.740）. Conclusion There are varying degrees of difference between GTVCT and GTVPET-CT in both volume differentials and coherence . Compared to CT, PET-CT could improve the accuracy of radio-therapy. Patients with lymphatic metastasis would most likely benefit from it.