Bone assessment via thermal photo-acoustic measurements

Abstract

The feasibility of an innovative biomedical diagnostic technique, thermal photoacoustic (TPA) measurement, for non-ionizing and non-invasive assessment of bone health is investigated. Unlike conventional photoacoustic PA methods which are mostly focused on the measurement of absolute signal intensity, TPA targets the change in PA signal intensity as a function of the sample temperature, i.e. the temperature dependent Grueneisen parameter which is closely relevant to the chemical and molecular properties in the sample. Based on the differentiation measurement, the results from TPA technique are less susceptible to the variations associated with sample and system, and could be quantified with improved accurately. Due to the fact that the PA signal intensity from organic components such as blood changes faster than that from non-organic mineral under the same modulation of temperature, TPA measurement is able to objectively evaluate bone mineral density (BMD) and its loss as a result of osteoporosis. In an experiment on well-established rat models of bone loss and preservation, PA measurements of rat tibia bones were conducted over a temperature range from 37 °C to 44 °C. The slope of PA signal intensity verses temperature was quantified for each specimen. The comparison among three groups of specimens with different BMD shows that bones with lower BMD have higher slopes, demonstrating the potential of the proposed TPA technique in future clinical management of osteoporosis.

Impact of System Factors on the Performance of Photoacoustic Tomography Scanners

“…PAT can visualize biological samples at scales from organelles, cells, tissues, and organs to the small-animal whole body and can reveal multidimensional biological information, such as anatomical, functional, molecular, genetic, and metabolic data [1]. PAT has unique applications in a range of biomedical fields [4,5], such as cell biology [6][7][8][9], neurology [10][11][12], oncology [13,14], rheumatology [15], and ophthalmology [16,17]. Both basic sciences and clinical translations involving PAT are expected to grow in the future.…”

Characterization of bone microstructure using photoacoustic spectrum analysis

“…Photoacoustic (PA) imaging and sensing, an emerging hybrid technology involving both light and sound, has excellent sensitivity to the chemical and physiological information in biological samples and has been explored for potential application in the diagnosis of osteoporosis [8][9][10][11][12][13][14][15]. Most of the previous research on PA evaluation bone were focused on either the chemical components or ultrasound properties of bone.…”

Repositioning Clofazimine as a Macrophage-Targeting Photoacoustic Contrast Agent

“…where Γ is the Grüneisen parameter, which is a constant and Φ is the laser fluence, which was calibrated using the reference black body 56 . Clofazimine (CFZ) as a free base was obtained directly from Sigma-Aldrich (St. Louis, MO, Catalogue No.…”