PET Imaging of Brain Amyloid Using [11C]MeS-IMPY

Alzheimer's disease (AD) is characterized pathologically by the presence of beta-amyloid
plaques in brain. A substantial body of research indicates that the presence of increased
beta -amyloid peptide is neurotoxic, and may initiate further pathology observed in AD
including neurofibrillary tangles, synaptic loss and dysfunction, and neurodegeneration.
There are multiple binding sites available on beta-amyloid plaques. Three clearly identified
sites are Congo-red type, Thioflavin-T type, and FDDNP type. Radioligands currently under
development using positron emission tomography (PET) for studying beta-amyloid in clinical
research or drug development are based on Thioflavin-T site, such as [11C]PIB and
[11C]SB-13. Though variously effective, these radioligands have one or more drawbacks with
respect to measuring relative regional beta-amyloid densities. Therefore, we have recently
developed [11C]MeS-IMPY as an alternative radioligand for imaging beta-amyloid, which will
allow a more accurate quantification of amyloid plaques in AD brain. In the current
protocol, we wish to evaluate [11C]MeS-IMPY in both healthy subjects and AD patients to
determine the kinetics of brain imaging beta-amyloid plaques in AD patients.

- INCLUSION CRITERIA:

Healthy control subjects aged 18-90 years and AD patients aged 50-90, with
history/physical exam, ECG, and laboratory tests.

Informed Consent.

AD Patients: Mini-Mental State Examination (score greater than or equal to 10).

AD Patients: Meet NINCDS-ADRDA criteria for probable AD.

EXCLUSION CRITERIA:

1. Current or prior history of any alcohol or drug abuse.

2. Severe systemic disease based on history and physical exam.

3. Positive result on urine screen for illicit drugs.

4. Laboratory tests with clinically significant abnormalities.

5. Prior participation in other research protocols or clinical care in the last year
such that radiation exposure would exceed the annual limits.

6. Pregnancy or breast feeding.

7. Claustrophobia.

8. Presence of ferromagnetic metal in the body or heart pacemaker.

9. History of brain disease other than Alzheimer's disease.

10. Unable to lay on one's back for the PET/MRI scan.