A high-speed 16-mm cineradiographic system previously developed at the University of Michigan, Highway Safety Research Institute, for use in biosciences research has been upgraded in capability by 1) increasing the x-ray field to 35-cm (14-in) by 43-cm (17-in), 2) incorporating a 35-mm high-speed motion picture to increase resolution, and 3) acauisition of a second x-ray head for three-dimensional x-ray stereophotogrammetric studies. This system now consists of a 35-mm Photosonics 4B camera, capable of 2500 frames per second, which views a 50-mm (2-in) diameter output phosphor of a highgain, 4-stage, magnetically focused image intensifier tube, gated on and off synchronously with the motion picture camera. A lens optically couples the input photocathode of the image tube to x-ray fluorescent (rare earth) anteelnimages produced by a smoothed d-c x-ray generator of a conventional type. The system is capable of a wide range of magnification ratios.