Molecular Imaging of Alzheimer’s Disease Using PET

Molecular Imaging Techniques Molecular imaging of the brain aims to quantify various biological processes via the modeling of interactions between a molecular probe and a molecule of interest naturally occurring in a living organism. Brain molecular-imaging techniques such as positron emission tomography (PET) and single photon emission tomography (SPECT) allow clinical investigators to record and analyze such interactions in vivo. PET and SPECT associated with specific molecular probes are sensitive to detecting biological processes in the order of pico-molar (10-12), however these techniques have limited spatial resolution. In contrast, magnetic resonance imaging (MRI) has a tremendous spatial resolution (sub-milliliter range) but lower sensitivity (micromolar; 10-6) relative to PET and SPECT (Table 1). Together, these techniques reveal critical information with regards to the alterations in the brain’s anatomy and physiology witnessed in dementia, as well as canalizing diagnostic methods and therapeutic interventions.