In vivo Optical Measurement of Bone Strength Using Raman Spectroscopy

Abstract

Although there are a variety of clinical techniques to measure bone mineralization and structure, bone mineral density alone is not fully indicative of bone strength. Raman spectroscopy is a technique that provides chemical information that cannot be measured by standard methods. In this study, transcutaneous measurements of bone were made using Raman spectroscopy. Using partial least squares regression, a model was created that uses a Raman spectrum to predict three biomechanical properties: areal bone mineral density, volumetric bone mineral density, and maximum torque. These properties were measured for each bone using dual-energy X-ray absorptiometry (DEXA), micro computerized tomography (micro-CT) imaging, and torsion testing, respectively. Recently, our group empirically found significant correlations between the Raman predicted values and the reference values for each of the three parameters. We then began to investigate how the predictive model works in order to gain a deeper understanding of the relevant chemical information and limiting factors in the prediction. We can then begin to explore possible improvements to the prediction technique in order to create a more robust method that can be used across a variety of optical systems, and potentially give insight into bone chemistry.