There is actually no dearth of DICOM viewing software out there. DICOM images are unique in the fact that they contain patient information in addition to the image data. The purpose of a DICOM application is to store information in the PACS about the imaging examination, along with patient details, and then when required, to view and interpret (and possibly edit) medical images that are retrieved from the PACS.
The images, along with the corresponding patient data, are often stored in a large database called the Picture Archiving and Communication System (PACS). DICOM images need to be viewed through specific software called DICOM viewers that can read and display the format.
DICOM (Digital Imaging and Communications in Medicine) is a standard format that enables medical professionals to view, store, and share medical images irrespective of their geographic location or the devices they use, as long as those devices support the format.