A method and a computing unit are disclosed for measuring and displaying the bone density of a patient. In at least one embodiment, separate projection data are used from a CT scan with at least two different x-ray energy regions volume displays for bone material and at least one further material composition are generated two DEXA projection recordings with different x-ray energy spectra are simulated from these volume displays the two simulated DEXA projection recordings are used to determine the specific bone mass density according to the DEXA method and at least one projection recording and at least one average specific bone mass density are output.
