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Molecular imaging is a new and evolving field that employs a targeted approach to noninvasively assess biologic processes in vivo. By assessing key elements in specific cellular processes prior to irreversible end-organ damage, molecular tools will allow for earlier detection and intervention, improving management and outcomes associated with cardiovascular diseases. The goal of those working to expand this field is not just to provide diagnostic and prognostic information, but rather to guide an individual's pharmacological, cell-based, or genetic therapeutic regimen. This article will review molecular imaging tools in the context of our current understanding of biological processes of the myocardium, including angiogenesis, ventricular remodeling, inflammation, and apoptosis. The focus will be on radiotracer-based molecular imaging modalities with an emphasis on clinical application. Though this field is still in its infancy and may not be fully ready for widespread use, molecular imaging of myocardial biology has begun to show promise of clinical utility in acute and chronic ischemia, acute myocardial infarction, congestive heart failure, as well as in more global inflammatory and immune-mediated responses in the heart-like myocarditis and allogeneic cardiac transplant rejection. With continued research and development, molecular imaging promises to be an important tool for the optimization of cardiovascular care.

The successful management of prostate cancer requires early detection, appropriate risk assessment, and optimum treatment. An unmet goal of prostate cancer imaging is to differentiate indolent from aggressive tumors, as treatment may vary for different grades of the disease. Different modalities have been tested to diagnose, stage, and monitor prostate cancer during therapy. This review briefly describes the key clinical issues in prostate cancer imaging and therapy and summarizes the various new imaging modalities and agents in use and on the horizon.

A promising role of cellular therapies in cancer treatment is reflected by the constantly growing number of clinical trials with adoptively transferred cells. Direct and indirect cell labeling for the nuclear imaging of transferred cells has been proven reliable for imaging adoptive cellular therapies. Both methods show their advantages and limitations. Direct labeling is a relatively easy, inexpensive, and well-established methodology. Indirect labeling using a reporter gene imaging paradigm allows for reliable, stable, and harmless visualization of cellular trafficking, persistence, proliferation, and function at the target site. It is expected that new human-derived reporter genes will be rapidly translated into clinical applications that require repetitive imaging for the effective monitoring of various genetic and cellular therapies.

The objective of cardiac stress testing is to detect coronary artery disease (CAD) and to prevent future adverse events, such as myocardial infarction or death. The progression from electrocardiographically based stress testing to current SPECT and PET technologies has brought improvements in diagnostic efficacy and resolution. Myocardial perfusion imaging facilitates management of CAD in elective and acute settings by providing valuable diagnostic and prognostic information. Hybrid PET/CT and SPECT/CT systems impart complementary information of coronary anatomy and its physiologic significance on blood flow reserve. In the current era, diagnosis and treatment of cardiovascular disease is increasingly defined by underlying molecular and genomic aberrations rather than by clinical signs and symptoms alone. Nuclear imaging is uniquely primed to exploit the targeting of expressed cell-surface molecules and intracellular processes of cardiovascular disease and to foster the development of innovative therapeutic interventions in the future.

The development of novel drugs is a lengthy process requiring years of preclinical research and many steps indispensable to ensure that the molecule of interest can be administered to humans with a minimal risk of toxic effects. Even a minimal reduction in the initial stages of drug development would result in a tremendous saving in time; therefore, pharmaceutical companies are eager to apply novel methodologies that shorten the time required for pharmacodynamic, pharmacokinetic and toxicological studies to be carried out in vitro and in animal systems. Currently, quantitative analysis of molecular events in living organisms is done with the combined application of imaging and genetic engineering technologies. In vivo imaging provides surrogate endpoints that can improve the identification of new drug candidates and speed up their research at preclinical stages. The integration of reporter systems in animal models of human diseases represents a reachable frontier that will dramatically advance drug development in terms of costs, time and efficacy. The present review outlines the applicability of imaging technologies for drug development and presents a panorama on the state of the art of currently available imaging technologies suitable for preclinical studies, with particular focus on bioluminescence and fluorescence as the methodologies of election.

This review examines several classes of radiolabeled agents, including analogs localizing in somatostatin, benzodiazepine and dopamine receptors; analogs of progesterone and estrogen; and agents localizing in lesions with hypoxia. It concludes the status of agents advocated for detecting angiogenesis and inflammation. The current clinical status of these agents, and their potential roles in diagnosis and treatment are discussed.