Sixty-four–slice CT typified the dramatic race in technical development in radiology. Featuring high spatial resolution with 0.5-mm thin slices and 0.3-second gantry revolution times, it has become state-of-the-art technology in CT imaging shortly after its clinical introduction. Three-dimensional tube modulation together with adaptive x-ray shutters led to significant dose reduction to the patients while improving image quality because of implementation of optimized reconstruction algorithms. The latest innovations—new detector materials, dual-layer detector, dual-source and dynamic volume CT—represent the pinnacles in CT imaging, pursuing different directions to further clinical applications of CT.