Figure 1.

Intrapatient heterogeneity in the expression of α_Vβ₃ integrin imaged by PET with the α_Vβ₃ ligand [¹⁸F]galacto-RGD. The primary tumor, a soft tissue sarcoma of the thigh (arrow in the CT image in A), demonstrates intense uptake of [¹⁸F]galacto-RGD, indicating high expression levels of α_Vβ₃ integrin (arrow in B). Uptake of [¹⁸F]galacto-RGD is much less pronounced in a bone metastasis in the pelvis and a right-sided lung metastasis (arrows in D). The bottom image in C shows the pelvic metastasis on CT (arrows). A left-sided lung metastasis, shown on CT (C, top) is negative on the [¹⁸F] galacto-RGD PET scan (D). Permission obtained from the Society of Nuclear Medicine © Beer AJ et al. (2005) Biodistribution and pharmacokinetics of the α_Vβ₃-selective tracer 18F-galacto-RGD in cancer patients. J Nucl Med 46: 1333–1341. Abbreviations: RGD, arginine–glycine–aspartic acid; SUV, standardized uptake value.