This article discusses the importance of addressing patient motion in positron emission tomography (PET) imaging for reliable parametric imaging. The introduction of new technologies in PET imaging has allowed for more insightful information about physiological processes and tissue differentiation. However, patient motion during the extended acquisition protocol can significantly impact the quality and reliability of parametric PET images. The article highlights the consequences of motion on parametric images, such as reduced lesion volume and erroneous quantification. It emphasizes the need for robust methods to correct for patient motion in order to ensure accurate parametric analysis and avoid misdiagnoses and inadequate treatment planning.