TCIA is a service which de-identifies and hosts a large archive of medical images of cancer accessible for public download. The data are organized as "collections"; typically patients' imaging related by a common disease (e.g. lung cancer), image modality or type (MRI, CT, digital histopathology, etc) or research focus. DICOM is the primary file format used by TCIA for radiology imaging. Supporting data related to the images such as patient outcomes, treatment details, genomics and expert analyses are also provided when available.