FIGURE 1. Attenuation-corrected PET image (A), PET/CT fusion image (B), CT image (C), and PET image uncorrected for attenuation (D) of 43-y-old woman with centrally located non–small cell cancer of right lung and mediastinal lymph node metastasis. PET attenuation artifact is due to highly concentrated contrast agent in right subclavian vein (arrow in A), which is not detectable on PET image uncorrected for attenuation (D). On attenuation-corrected PET, hot spot in right axillary region could be misinterpreted as metastasis.