Three-dimensional (3D) image data generated by modalities such as CT and MRI can provide a physician with insight. Analysis of such data has traditionally been done using time- consuming, error-prone manual techniques. Automating this analysis can improve the consistency of the results and reduce the amount of user interactive time required. Automated analysis, however, carries with it a tremendous computational burden. To address this problem, we have designed a distributed processing environment for the rapid processing of 3D radiological images. Our system enables sequences of image processing operations (filtering, morphology, segmentation, etc.) to be linked together. These sequences are then rapidly carried out by distributing the computational load across a network of workstations and a massively parallel computer, using the PVM protocol. A graphical user interface facilitates system operation, making the low-level parallel processing issues transparent to the user.