A reflection scanning acoustic microscope for bone and bone‐biomaterials interface studies

Abstract
A relatively simple scanning acoustic microscope (SAM) that operates in the reflection mode has been constructed. The system uses a 20 MHz spherically focused transducer, acting both as transmitter and as detector, to obtain acoustic impedance information on a thin surface layer at a maximum resolution of approximately 100 μm. The specimen is mounted on an X-Y driving system (precision, 5 μm) under computer control in order to scan a grid of 256 × 256 points across areas ranging from 6.5 to 1300 mm2. An algorithm is used to reference the data against standards; specially developed software provides for pseudo-color mapping, three-dimensional images, zooming to 16X magnification, contouring, and single line profiles of the data. The system has been used to determine inhomogeneities in surface acoustic properties of mineralized tissues and implant materials, in many cases as a complement to using ultrasonic wave propagation techniques to measure the bulk anisotropic properties.