A computer-assisted didactic interactive system for radiology is described; it was implemented on a widely available, cost-effective personal computer with advanced graphic features. A set of suitable CT images was selected and digitized with a specific software that also allowed to process the acquired images. After adding graphic and textual comments, the images were ready to be put in the tutorial. A second software tool was used to manage the image display and to control the correct sequence of the interactive steps of the tutorial. A series of computer-driven multiple-choice questions was prepared to provide the user with a tool improving his/her knowledge of the topics covered by the system, in a simple and unconventional way. The tutorial was designed so that both the absolute number and the percentage of correct answers can be displayed and the critical evaluation of incorrect answers is automatically performed; in the end, the system goes back to the first screen and the tutorial can be run again. The system performance is good with standard hardware; it can be markedly improved with the integration of peripherals--i.e. hard disk. In the next future, the commercial availability of more advanced storage media (videodisks and optical disks) will dramatically improve the archiving capacity and will reduce access times.