Osteoporosis, characterized by the loss of bone mass leading to non-traumatic fractures, poses a major health concern in the elderly population. The current gold standard for osteoporosis diagnosis is dual-energy X-ray absorptiometry (DXA), which measures bone mineral content (BMC) or bone mineral density (BMD). However, DXA has limitations, including radiation exposure, high device cost, and restricted availability to large medical facilities. Furthermore, osteoporosis is not solely the result of reduced bone mass; bone quality parameters such as strength also contribute significantly to fracture risk.
As an alternative, ultrasound has emerged over the past two decades as a promising modality for assessing bone properties. Ultrasound propagation is a mechanical process influenced by the physical properties of the medium, including density and Young’s modulus. In clinical practice, commercial ultrasound devices are already used as preliminary screening tools for osteoporosis. These devices typically measure acoustic properties at the calcaneus, but this single-point measurement provides limited information about the distribution of bone properties, such as density, throughout the bone.
To address this limitation, acoustic scanning techniques have been developed to generate raster-based images analogous to X-rays. Our lab designed and built an acoustic scanning device capable of producing detailed ultrasound images of the human calcaneus. The system consists of a two-dimensional moving stage controlled by an embedded motion-control system, a coaxial ultrasound transmitter and receiver, and a desktop computer. The computer manages the scanning process, acquires ultrasound signals, and performs data analysis. The system software, developed in C++, operates on the Windows XP platform. The device generates three types of ultrasound images: ultrasound attenuation, broadband ultrasound attenuation, and ultrasound velocity.
This system has been successfully deployed in both clinical testing and NASA’s bed rest study, demonstrating its potential as a research and diagnostic tool for bone health assessment.