Abstract
A phantom consisting of water- and bone-equivalent solid materials was devised to test peripheral bone densitometry systems. A circular cross section with a diameter of 60 mm was chosen, with the sides flattened by 1 cm to model the forearm. Three inserts with precisely 50, 100 and 200 mg cm-3 hydroxyapatite simulate trabecular bone and provide the basis for the linearity check of PQCT systems. Density and thickness of the simulated compact bone is selected such that the phantom can also be used to calibrate DXA and SPA machines. Quality control with CT showed a homogeneously distributed trabecular bone with an average density that deviates less than 1 mg cm-3 from linearity. The phantom is presently used in the multicentre study of the COMAC-BME project 'quantitative assessment of osteoporosis' as a reference relative to which all peripheral bone mineral work is reported. Furthermore, trabecular bone density of peripheral and axial measurements can now be compared since the inserts used in the forearm phantom are identical to those used in the previously reported spine phantom.