Extracellular amyloid deposition in brain tissue is a hallmark of Alzheimer’s disease. Despite being the most common neurodegenerative disorder, it poses a major diagnostic challenge due to the lack of disease-specific biomarkers. Additionally, plaque-forming amyloid deposits are not unique to Alzheimer’s disease, but are also present in a high proportion of the elderly, as well as in patients with other neurodegenerative conditions such as dementia with Lewy bodies. Histopathological examination is the only reliable method for diagnosing the disease, but it is practically impossible to perform in vivo. Since Alzheimer’s disease is a disorder that develops asymptomatically over many years and eventually leads to severe dementia, new insights into the risk factors and markers of disease progression in the preclinical stage of the disease are needed. A better understanding of the underlying pathology is essential for the development of new therapies. In the past, this understanding came mainly from pathological studies. Positron emission tomography (PET) imaging detects the presence and activity of pathophysiological processes in vivo. By targeting different biological pathways, PET elucidates the metabolic activity of the processes that drive disease progression. Ongoing studies aim to clarify whether amyloid PET imaging can also be useful in assessing treatment response. In this review, recent advances in amyloid PET imaging that have significantly improved our understanding of the pathological basis of this disease are discussed.