Study Description: This pilot/exploratory study will examine whether cyclooxygenase 1 (COX-1) and COX-2 are elevated in the brain of individuals with dementia compared to healthy volunteers.

Objectives: Primary Objective: To determine whether COX-1 or COX-2 is elevated in the brains of individuals with dementia compared to healthy volunteers.

Endpoints: Primary Endpoint: Measurement of COX-1 and COX-2 density in brain after PET scans with [11C]PS13 and [11C]MC1, respectively.

Study Population: Four groups of 16 subjects each will be studied: 1) Alzheimer s disease (AD), 2) frontotemporal dementia (FTD) 3) other dementias, and 4) healthy volunteers. Subjects may be male or female. They must be greater than or equal to 18 years old, but most are expected to be 60 to 80 years old. Subjects may be recruited from anywhere, but most are expected to come from the Washington DC metropolitan area. Patients must be in good medical health but may be unable to provide informed consent because of cognitive impairment. In that case, the Legally Appointed Representative (LAR) must provide consent, and the patient must provide assent.

Phase: 1

Description of Sites/Facilities Enrolling Participants: Screening and PET imaging will be performed at the NIH Clinical Center.

Description of Study Intervention:

Subjects will be intravenously injected with 20 mCi of each of two radioligands: [11C]MC1 and [11C]PS13. Subjects will also have a radial artery catheter(s) inserted to measure the concentration of radioligand (either one insertion (if both scans are performed on the same day) or two insertions (if the scans are performed on two different days). Subjects will also have a brain MRI to provide anatomic orientation for the PET scans.

Study Duration: 36 months

Participant Duration: One week to four months, depending on the patient s availability and access to MRI and PET cameras.