Medical three-dimensional (3D) printing is playing an increasingly important role in clinical practice. The use of 3D-printed models in patient care offers a wide range of possibilities in terms of personalized medicine, training and education of medical professionals, and communication with patients. Datasets from imaging modalities such as computer tomography (CT) and magnetic resonance imaging (MRI) provide the basis for the majority of 3D models in medicine. The image acquisition, processing, and interpretation of these lie within the responsibility and expertise of radiology, which therefore plays a key role in the application and further development of 3D printing. Understanding the process of image acquisition, data processing, manipulation, and post-processing is essential for leveraging the full potential of 3D-printed products.