All current small animal imaging requires some form of anesthetization. The anesthetization not only may interfere with the subject's pathophysiology under study, and also is a costive and skill-demanding process. The current invention will eliminate the need for administration of anesthesia during small animal micro-CT imaging experiments, thus leading to high efficient and cost-effective imaging process. Furthermore, the ultrafast data acquisition speed of the disclosed micro-CT imaging system will allow imaging fast dynamic within the animal subject with high temporal resolution. Additionally, the micro-CT imaging system cut down radiation does by up to 85%, dramatically reducing the risks from radiation during x-ray imaging.