Department of Radiotherapy, Shanghai Cancer Center, Fudan University, Shanghai, China.
J Nucl Med. 2010 Oct;51(10):1517-23. doi: 10.2967/jnumed.110.077974. Epub 2010 Sep 16.
Previously, we showed that a CT window and level setting of 1,600 and -300 Hounsfield units, respectively, and autocontouring using an (18)F-FDG PET 50% intensity level correlated best with pathologic results. The aim of this study was to compare this autocontouring with manual contouring, to determine which method is better.
Seventeen patients with non-small cell lung cancer underwent (18)F-FDG PET/CT before surgery. The maximum diameter on pathologic examination was determined. Seven sets of gross tumor volumes (GTVs) were defined. The first set (GTV(CT)) was contoured manually using only CT information. The second set (GTV(Auto)) was autocontoured using a 50% intensity level for (18)F-FDG PET images. The third set (GTV(Manual)) was manually contoured using a visual method on PET images. The other 4 sets combined CT and (18)F-FDG PET images fused to one another to become composite volumes: GTV(CT+Auto), GTV(CT+Manual), GTV(CT-Auto), and GTV(CT-Manual). To quantitate the degree to which CT and (18)F-FDG PET defined the same region of interest, a matching index was calculated for each case. The maximum diameter of GTV was compared with the maximum diameter on pathologic examination.
The median GTV(CT), GTV(Auto), GTV(Manual), GTV(CT+Auto), GTV(CT+Manual), GTV(CT-Auto), and GTV(CT-Manual) were 6.96, 2.42, 4.37, 7.46, 10.17, 2.21, and 3.38 cm(3), respectively. The median matching indexes of GTV(CT) versus GTV(CT+Auto), GTV(Auto) versus GTV(CT+Auto), GTV(CT) versus GTV(CT+Manual), and GTV(Manual) versus GTV(CT+Manual) were 0.86, 0.65, 0.88, and 0.81, respectively. Compared with the maximum diameter on pathologic examination, the correlations of GTV(CT), GTV(Auto), GTV(Manual), GTV(CT+Auto), and GTV(CT+Manual) were 0.87, 0.83, 0.93, 0.86, and 0.94, respectively.
The matching index was higher for manual contouring than for autocontouring using a 50% intensity level on (18)F-FDG PET images. When using a 50% intensity level to contour the target of non-small cell lung cancer, one should also consider using manual contouring of (18)F-FDG PET to check for any missed disease.
比较手动勾画与自动勾画（使用（18）F-FDG PET 50% 强度水平），确定哪种方法更好。
17 例非小细胞肺癌患者于术前接受（18）F-FDG PET/CT 检查。确定病理检查的最大直径。定义了 7 个最大肿瘤体积（GTV）。第一组（GTV（CT））仅使用 CT 信息手动勾画。第二组（GTV（Auto））使用（18）F-FDG PET 图像的 50%强度水平自动勾画。第三组（GTV（Manual））使用 PET 图像上的视觉方法手动勾画。其他 4 组将 CT 和（18）F-FDG PET 图像融合在一起成为复合体积：GTV（CT+Auto）、GTV（CT+Manual）、GTV（CT-Auto）和 GTV（CT-Manual）。为了定量 CT 和（18）F-FDG PET 定义相同的感兴趣区域的程度，为每个病例计算了匹配指数。将 GTV 的最大直径与病理检查的最大直径进行比较。
GTV（CT）、GTV（Auto）、GTV（Manual）、GTV（CT+Auto）、GTV（CT+Manual）、GTV（CT-Auto）和 GTV（CT-Manual）的中位数分别为 6.96、2.42、4.37、7.46、10.17、2.21 和 3.38cm3。GTV（CT）与 GTV（CT+Auto）、GTV（Auto）与 GTV（CT+Auto）、GTV（CT）与 GTV（CT+Manual）和 GTV（Manual）与 GTV（CT+Manual）的中位数匹配指数分别为 0.86、0.65、0.88 和 0.81。与病理检查的最大直径相比，GTV（CT）、GTV（Auto）、GTV（Manual）、GTV（CT+Auto）和 GTV（CT+Manual）的相关性分别为 0.87、0.83、0.93、0.86 和 0.94。
与使用（18）F-FDG PET 图像 50%强度水平自动勾画相比，手动勾画的匹配指数更高。当使用 50%强度水平勾画非小细胞肺癌靶区时，还应考虑使用（18）F-FDG PET 的手动勾画来检查是否有遗漏的病变。
