Figure 2. (a) The location of the manufacturer's region of interest (ROI_M) and the anatomical region of interest ROI_A where bone mineral density was analysed, where R1 represents ROI_M and R2 represents ROI_A. The upper image shows the ROIs determined using the Sahara device and the lower image are the ROIs determined using the Achilles+ device. (b) An example of how the true dimension has been calculated for each subject. True calcaneal length=measured calcaneal length x (true ring diameter/measured diameter).