Gene expression of diagnostic biomarkers typically occurs at low concentrations, requiring highly sensitive imaging strategies to distinguish diseased from surrounding normal tissue. An important approach to minimize background signal is to silence the signal from an imaging agent until subsequent selective activation by specific biomolecules. Alternatively, activation of specific genes can produce proteins that bind to and trap molecular imaging agents in diseased tissue, amplifying the local signal. Different imaging modalities utilize either one or a combination of these strategies in molecular imaging. Combined with selective delivery, the new activation and signal amplification strategies provide distinct opportunities to advance the field of molecular imaging. The session will focus on recent advances in the applications of activation and signal amplification mechanisms in optical, nuclear, and magnetic resonance molecular imaging of tumors.
Educational Session: New Activation and Signal Amplification Strategies in Molecular Imaging

New activation mechanisms for optical molecular imaging of tumors; Hisataka Kobayashi. NCI-CCR, Bethesda, MD

Complementary molecular activation mechanisms in multimodal molecular imaging; Samuel Achilefu. Washington University School of Medicine, Saint Louis, MO

In vivo imaging techniques for cancer and gene therapy; Daniel Meruelo. New York University School of Medicine, New York, NY,