Special issues in quantitation of brain receptors and related markers by emission computed tomography

Emission computed tomography provides an opportunity to quantify neurotrans mitter-neuroreceptor systems in vivo. La order to do so, very high image qu ality and quantitative accuracy are required. Quantitation of receptor syst ems involves considerations of physical effects (such as finite spatial res olution, scatter, and attenuation), instrumentation design (such as spatial sampling), image processing (such as filtering), and data analysis (such a s kinetic modeling). Appropriate application of these considerations can le ad to useful results, but emerging approaches promise even greater levels o f accuracy and precision.