Fiber Bragg grating sensor for monitoring bone decalcification

Introduction: Estimation of decalcification is a vital tool to discern bone health. Different techniques are used for its quantitative measurement, e. g. DEXA, QCT & QUS. All these techniques, although noninvasive, suffer from limitations such as radiation exposure and inaccurate values. Recently, fiber optic techniques are fast emerging for medical applications owing to their various attractive features like immunity to EMI/RFI, geometric versatility, chemical inertness, etc. Material and methods: The effect of decalcification on strain response of a goat tibia was investigated in vitro using fiber Bragg grating (FBG) sensing technique. The bone was strained by using three-point bending technique and corresponding Bragg wavelength shifts were recorded. Two similar bone samples from the same animal were taken and one was partially decalcified. Strain response of decalcified and untreated bone was taken concurrently to monitor the effects of calcium loss and that of degradation with time. Results and conclusion: The strain generated for same stress increased with greater degree of decalcification and a steep increase occurred after 2 g calcium loss, indicating the onset of damage. The strain response, therefore gives a direct indication of the degree of calcium present in the bone. Level of evidence: Level III. (c) 2010 Elsevier Masson SAS. All rights reserved.