Variation in the tube voltage causes a substantial change in patient CT dose and image quality [50]. The use of 80 kVp for spinal single-slice QCT reduces the dose substantially in comparison with acquisition at 120 kVp. The possibility of tube voltage reduction in MDQCT should be investigated, especially for patients with small body size. Reduction of tube load may reduce patient dose considerably. Automatic exposure control (AEC) tools adjust the tube current in the x–y plane and along z axis simultaneously, based on the size and attenuation of the anatomical area being examined to achieve an operator-defined level of image quality with the lowest possible dose. The use of AEC provides a substantial potential for dose reduction compared with the fixed mA technique. In AEC-activated examinations, the mAs product can be reduced by typically between 15% and 60% [51, 52].