Nicolaas Paul L.G. Verhoeff, MD, PhD, FRCPC, DABPN, is a clinician scientist at the Kunin-Lunenfeld Applied Research Unit at Baycrest Centre for Geriatric Care. His research focuses on the early detection of Alzheimer's disease (AD) by developing novel positron emission tomography (PET) radiotracers for beta-amyloid in the brain. In collaboration with the PET Centre at the Centre for Addiction and Mental Health, several candidate amyloid PET radiotracers have been developed that bind selectively to beta-amyloid aggregates in vitro. The two most promising candidate beta-amyloid PET radiotracers have been tested in vivo in humans and both showed a good ability to discriminate AD patients from matched healthy comparison subjects. Besides for early detection of AD, this technique can also be used to monitor the efficacy of beta-amyloid-reducing medications.