Nuclear imaging of inflammation: homing-associated molecules as targets

Abstract

The golden standard in nuclear medicine imaging of inflammation is the use of autologous radiolabeled leukocytes. Although their diagnostic accuracy is precise, the preparation of the leukocytes is both laborious and potentially hazardous for laboratory personnel. Molecules involved in leukocyte migration (homing-associated molecules) could serve as targets for the development of imaging agents for inflammation. An excellent target would be a molecule that is absent or expressed at low levels in healthy tissues, but is present or upregulated at the sites of inflammation. In this paper, we will review the literature concerning the use of homing-associated molecules as imaging targets. We will especially concentrate on vascular adhesion protein-1 due to the promising results regarding its use as a target for the imaging of inflammation.

Figure 1

VAP-1 targeting imaging agents in detecting inflammation. (a) PET images of ⁶⁸Ga-labeled VAP-1 binding peptides in a rat model of sterile skin/muscle inflammation. All the images fall within the same radioactivity scale and the scale bar is shown on the left. (b) Inflammation-to-muscle ratios obtained from PET imaging at 60 min after injection.