Alzheimer’s disease is the most common cause of dementia worldwide. It is a progressive neurodegenerative disorder for which we currently have no cure or disease modifying therapies to slow disease progression. Alzheimer’s disease is often preceded by a prodromal phase called mild cognitive impairment which is characterised by decline in cognitive performance. Neuropathological hallmarks of Alzheimer’s disease and mild cognitive impairment are β-amyloid (Aβ) plaques and intracellular tau neurofibrillary tangles. Using positron emission tomography (PET) with specific tracers it is possible to measure levels of β-amyloid (Aβ) and tau in living humans (in vivo). Sitilop is collaborating with Life Molecular Imaging and Alliance Medical to evaluate tau depositions in Alzheimer’s disease and mild cognitive impairment using a novel tau PET tracer.