Purpose: Current positron emission tomography (PET) radioligands for detection of Abeta amyloid in Alzheimer's disease (AD) are not ideal for quantification. To improve the signal to noise ratio we have developed the radioligand [(11)C]AZD2184 and report here the first clinical evaluation.
Methods: Eight AD patients and four younger control subjects underwent 93-min PET measurements with [(11)C]AZD2184. A ratio approach using the cerebellum as reference region was applied to determine binding parameters.
Results: Brain uptake of [(11)C]AZD2184 peaked within 1 min at 3-4% of injected radioactivity. AD patients had high radioactivity in cortical regions while controls had uniformly low radioactivity uptake. Specific binding peaked within 30 min at which time standardized uptake value ratios (SUVR) ranged between 1.19 and 2.57.
Conclusion: [(11)C]AZD2184 is a promising radioligand for detailed mapping of Abeta amyloid depositions in Alzheimer's disease, due to low non-specific binding, high signal to background ratio and reversible binding as evident from early peak equilibrium.