Bone Chemical Composition Assessment with Multi-Wavelength Photoacoustic Analysis

Abstract

In this study, the feasibility of assessing the chemical composition in bone using the multi-wavelength photoacoustic analysis (MWPA) method was investigated. By illuminating a bone specimen using laser light with a wavelength tunable over an optical spectrum from 680 nm to 950 nm, the optical absorption spectrum of the bone was acquired. Then, with the optical absorption spectra of all the optically absorbing chemical components in the bone known, a spectral unmixing procedure was performed to quantitatively assess the relative content of each chemical component. The experimental results from porcine rib bones demonstrated that the contents of the chemical components, including not only non-organic materials such as minerals and water but also organic materials including oxygenated hemoglobin, deoxygenated hemoglobin, lipid, and collagen, can all be assessed by MWPA. As the chemical composition in the bone is directly associated with functional and metabolic activities, the finding from this study suggests that the MWPA method could offer a new diagnostic tool for the non-invasive evaluation of bone health.

Wavelet transform-based photoacoustic time-frequency spectral analysis for bone assessment

“…Their PA-TFSs intuitively reflect the frequency spectrum distribution at each moment and the propagation attenuation of acoustic frequency over time. There are higher frequency components as the MTT decreases, which is consistent with the theory that PA signals produced from the thinner trabeculae have higher acoustic frequency components [ 26 , 45 ]. The high-frequency components in the PA-TFS of the two groups of bone samples attenuated over time.…”

“…Previous studies showed that the spectral parameter slope can quantitatively evaluate the trabecular thickness for bone health evaluation, as the thinner trabeculae can generate higher PA frequency by comparing with the thicker trabeculae [ 45 , 47 ]. Therefore, the osteoporotic bones with thinner trabecular bone have higher frequency components of PA-TFS, thus higher y-intercept and midband-fit than control bones.…”

The feasibility study of the transmission mode photoacoustic measurement of human calcaneus bone in vivo

“…The PASA in this work was conducted at 690-nm wavelength. According to our previous studies [ 37 , 55 ], both hydroxyapatite and hemoglobin contribute to the optical absorption of trabecular bone at this wavelength. Hence, PASA at 690 nm reflects the bone microarchitecture formed by both trabeculae and bone marrow.…”

Characterization of multi-biomarkers for bone health assessment based on photoacoustic physicochemical analysis method

“…Recently, our group evaluated the relative content of collagen in rabbit bone model ex vivo by performing multi-wavelength PA (MWPA) measurements at the wavelength of 1300 nm–1800 nm [25] . Feng et al also investigated the feasibility of PA assessment of human bone health in vivo by performing MWPA measurements [26] , [27] , [28] . Since the PA signals represent the spatial distribution of the optical absorption properties in biological tissue, past studies have indicated that this technique combines micrometer to centimeter morphologies and the chemical compositions of tissue specimens [29] , [30] , [31] , [32] , [33] , [34] , [35] .…”