Traditionally, radiologists have collected and saved interesting cases in their film formats to teach medical students, residents, and physicians. These cases are classified according to various coding schemes, although current schemes alone are insufficient to meet today's educational needs. Teaching methods and cases also vary among institutions, along with the manner in which instructors present information to their students. In order to address this problem, the authors developed a standardized radiology teaching knowledge database known as the Digital Radiology Image Learning Library (DRILL). DRILL is a relational image knowledge database providing access to standard mammography cases in digital image format along with a pool of clinical and radiological information on a per-case basis. The development platform chosen is a standard Apple Macintosh-II computer and the Oracle database environment. The data entry and query interfaces are implemented in HyperCard. Images are stored on magnetic disk but could be stored on optical media. Since the personal computer platform was chosen, a wide variety of course building tools are available through which a teacher can construct a course, such as authoring and multi-media systems for building computer based courses, or word processors for writing course outlines tests. The interface also provides image conversion tools which convert images into PC-compatible formats.