Table 3.

Approaches to key questions on drug development using appropriate preclinical imaging methods for translational research (adapted after [176]).

Issue	Question	Preclinical Imaging Approach
Validation	Does the therapeutic target play a key role in the pathophysiological mechanism?	MRI whole-body scan
Biodistribution	Does the molecule reach the targeted tissue? Can pharmacologically active concentrations be reached for the compound being studied?	Radiolabeling of the compound to study the distribution or interactions in the target area (use of PET, SPECT, or MRS)
Interactions	Does the studied molecule interact with the target receptor? What is the relationship between dose and effect?	Saturation studies (plasma concentration–occupancy–time) using PET or SPECT radiolabeling
Pharmacodynamics	What is the effect and duration of the compound?	Dynamic biochemical studies, structural or functional studies (non-ionizing radiation imaging techniques are recommended for long-term effects follow-up)
Toxicology	Does the compound have acute or chronic toxic effects?	Dynamic biochemical studies, structural or functional studies of at risk organs (MRI, CT, US)

MRI, magnetic resonance imaging; PET, positron emission tomography; H-MRS, proton magnetic resonance spectroscopy; SPECT, single-photon emission computed tomography; CT, computed tomography; US, ultrasonography.