As CT scanning is a very common medical imaging method, we propose new hardware-based algorithms using GPU (Graphical Processor Unit) programming for rapid visualization. Firstly, 3D volumes are constructed from CT scans. Then volume rendering is used to display anatomical structures via algorithms founded on improved ray casting and 2D textures. Our methods achieve interactive rendering rates and require an ordinary PC with an off-the-shelf graphics card. We expect our approach to be useful to medical practitioners for handling modern, large-scale medical datasets.