Receptor targeting agents for imaging inflammation/infection: where are we now?

Over the past 20 years, radiopharmaceutical research has brought to market a wide variety of drugs that aid in the management of infection and inflammation. Finding the best clinical application for existing radiopharmaceuticals can be a challenging task, as clinicians now have to choose from an array of many different radiopharmaceuticals, each suited to identify a specific type of inflammation. With this review, we describe the features of receptor-targeting agents and present the main advantages and limitations to their application in the diagnosis of inflammation and infection. The receptor-specific agents described here include peptides and antibodies as well as radiolabeled antibodies employed for the specific targeting of neutrophils, bacteria, lymphocytes, and molecules involved in inflammatory processes. Because these agents bind to specific receptors, they allow the mapping of receptor expression in vivo. Such mapping represents the future of nuclear medicine imaging, as it aids in diagnosing the type of inflammation, in therapy decision-making, in selecting suitable candidates for therapy, and in evaluating treatment efficacy.