Hologic 4500QDR 4500C The Hologic QDR 4500 X-ray Bone Densitometer brings fan beam scanning capability to a new advanced clinical/research level with enhanced performance and high-resolution images for all densitometry applications. Fan-beam scans faster without compromising precision or safety. The QDR 4500's optimal x-ray energies penetrate a broader range of patients to produce better quality images.