A digital video image processor (VIP) has been constructed and is presently being tested and used in a variety of preclinical medical imaging situations. Details of its design are discussed. The VIP can digitize, store and process images from a conventional radiographic TV fluoroscopy system. From these images a variety of subtraction images can be formed and displayed in real time at video rates. These subtraction images include: K-edge images, time dependent subtraction images, tomographic, and K-edge tomographic images. Examples of in vivo K-edge and time-dependent subtraction images are presented.