Pet Evaluation of Drugs in Alzheimer’s and Parkinson’s Diseases

In addition to the study of the distribution and kinetics of labeled drugs, positron emission tomography (PET) can improve the accuracy of diagnosis of Alzheimer’s and Parkinson’s diseases by imaging major metabolic changes (glucose metabolism, dopamine synthesis) that are typical for these diseases. It may thus reduce the variance of results and improve the statistical power of clinical trials. Subgroups of particular interest could be identified, for example, patients with mild symptoms which cannot be diagnosed accurately by clinical means but may show particularly good responses to therapy. PET may also provide objective measures of treatment effects, for example, increase of cerebral glucose metabolism as an indicator of neuronal activity that can corroborate neuropsychological or behavioral test results. An ultimate goal could be to prove neuroprotective drug action by demonstrating a stop of progression of the metabolic changes that are typical for Alzheimer’s and Parkinson’s diseases. Standard techniques are now available for these tasks in many laboratories that could also be used in multicenter trials. Diagnostic improvements could reduce the number of required patients and thus costs of clinical trials.