Hounsfield units

Depending on the type of CT scanner and the settings, the result of a CT scan of the same material can be different attenuation coefficient (grey-values). In order to make it easier to compare CT data, espe-cially in medicine, the grey-values of a CT scan are often rescaled to a standard scale. Hounsfield units is such a scaling that uses air and water as a calibration material which is regularly used in medicine.