**9. Novel diagnostic imaging modalities**

Because pancreatic cancer might metastasize at an early stage, an ideal imaging modality is one that would predict the biological behavior of the tumor. Understanding the molecular aspects of pancreatic cancer has facilitated use of investigational modalities in this area. Imaging agents such as peptides that bind to specific factors on the surface of pancreatic tumors have been developed and include: plectin 1 (Plec 1), integrin αvβ6, cathepsin E and claudin-4 [70-73]. Early studies have shown promising results, but more work is needed before routine clinical use.

A similar approach, but by interrogating normal tissue has also been investigated. Montet *et al.* demonstrated that as pancreatic tumors do not express receptors for bombesin, a bombesin peptide-coupled nanoparticle (BN-CLIO[Cy5.5]) can be used to image normal pancreas and hence, differentiate it from pancreatic tumors [74]. Similarly, a novel concept of microbubbles, small gas –filled microspheres, has been used in preliminary studies to image the peri-tumoral vasculature with the assistance of ultrasound. Moreover, this technology can also be used as a vehicle to deliver anti-cancer therapies [75].
