Anthropomorphic hip phantom. (a) Frontal view of the anthropomorphic hip phantom. (b) Concentration of HA in head, neck and greater trochanters for calibration hip and test hip. The pelvis inserts associated the old test hip contained 200 mg/cm3 of HA, whereas the pelvis inserts associated to the young test hip contained 400 mg/cm3 of HA. (c) Phantom with no, small and large girdle to simulate increasing body sizes. (d) The anthropomorphic hip phantom was scanned on top of a calibration phantom, which contains three chambers of 0, 75 and 150 mg/cm3 of HA, to convert Hounsfield Units to concentrations of HA.