Figure 1.

2D projection images of ¹⁸F-Alfatide II PET (A) and ¹⁸F-FDG PET (B) of a patient (no. 2) with metastatic adenocarcinoma of unknown primary site. ¹⁸F-Alfatide II PET demonstrated intense local accumulation of radioactivity in bone metastatic lesions located in thoracic vertebras, sacrum and right scapula, and right clavicle with good background contrast, whereas ¹⁸F-FDG PET only showed moderate uptake in some thoracic vertebras and sacral lesions. The transaxial CT (C), ¹⁸F-Alfatide II PET (D), and ¹⁸F-FDG PET (E) were presented to focus on the lesions at sacrum. There is also bone metastasis with abnormal ¹⁸F-Alfatide II uptake (G) but not visible by transaxial CT (F) or ¹⁸F-FDG PET (H).