An embodiment in accordance with the present invention provides a device and method for a quantitatively calibrated computed tomography scanner. The device includes a gentry configured for receiving a patient or part of a patient. The gentry includes an X-ray source and a detector positioned opposite said X-ray source, such that said detector receives the X-rays emitted from the X-ray source. Calibration phantoms are integrated with the gentry and/or a device within the scanner so as to allow for calibration in quantitative CT measurements of Hounsfield units and/or bone mineral density.