1. A computed tomography (CT) system, comprising: an x-ray source and x-ray detectors configured to helically scan an object at a low pitch resulting in overscanning at least a portion of the object, the detector obtaining attenuation measurements from the object as the object is moved in a Z-direction; a computer module identifying first and second portions of a region of interest (ROI) in the object, the second portion including an organ of interest (OOI) within the ROI, the first portion differing from the second portion; an x-ray controller providing a first tube current to drive the x-ray source when scanning the first portion and providing a different second tube current to drive the x-ray source when scanning the second portion, the scanning of the first portion and the second portion performed during a single scanning operation, with reduced current above and below the OOI; and a reconstruction module configured to reconstruct an image of the object utilizing redundancy resulting from the overscanning to enhance a signal to noise ratio of the OOI otherwise resulting from the reduced current above and below the OOI, wherein at least one of the first and second tube currents are modulated based on a physiologic parameter.