Research

Molecular imaging is a powerful new tool for early detection of diseases in the digestive tract because this emerging methodology can perform real time visualization of overexpressed targets in vivo. This technique can be developed to address the need for improved visualization of flat lesions by detecting early targets that are expressed well before structural changes become apparent. These targets can be visualized using highly specific molecular probes that provide a biological basis for detecting disease, establishing prognosis, guiding therapy, and monitoring treatment. Because cancer biology is heterogeneous, an approach that can detect multiple targets concurrently (multiplexing) is needed for broad clinical applicability to patients at increased risk for cancer.

Imaging applications - The digestive tract consists of hollow organs, such as esophagus, stomach, biliary tract, pancreas, small bowel, and colon, that are lines with epithelial cells that are highly metabolically active. Expression of unique cell surface targets are accessible to imaging, and can be visualized with highly specific molecular probes.

A number of different molecular probes are being developed for targeted in vivo imaging in the digestive tract, including activatable enzymes, antibody, apatamer, small molecule, peptide, and lectin. Each platform has its own strengths and weaknesses. Topical application is a promising approach for delivery of these molecular probes to the epithelium because binding can occur rapidly and predictably within a few minutes. This time scale provides minimal interruption to the work flow for performing endoscopy in high volume centers. High contrast images can be achieved with minimal risk for toxicity, and avoids undesired biodistribution of the molecular probe to other tissues, which is a major limitation with systemic delivery.

Current methods of imaging performed in the clinic include ultrasound, CT, MRI, and PET. Only molecular methods using optical imaging offer the specificity, spatial resolution and temporal speed needed to visualize pre-cancerous lesions that are flat and patchy in appearance and tumor margins in real time. Also, non-optical imaging modalities have limited ability to visualize multiple targets concurrently. Novel methods of optical imaging that can image multiple tumor targets in real time can significantly improve our ability to image disease found in the epithelium.