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Proceedings Paper

Picosecond time-gated Raman spectroscopy for transcutaneous evaluation of bone composition
Author(s): Michael D. Morris; Edward R. C. Draper; Allen E. Goodship; Pavel Matousek; Michael Towrie; Anthony W. Parker; Nancy P. Camacho
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Paper Abstract

For efficacious transcutaneous monitoring of bone mineralization and matrix quality a spatially averaged measurement is needed, often over a large area. This precludes the use of confocal microscopy. We use picosecond pulsed laser excitation and Kerr-gated time-resolved data collection techniques to obtain marker bands of bone condition whilst rejecting interfering Raman scatter from skin, tendon and other overlying tissue. Alternatively, the methodology can be used to collect signals only from these overlying tissues. In all these experiments the 1 ps pulsed laser beam is focused to approximately 1 mm diameter. Raman light is then collected at specific times following the arrival of the pulse at time delays typically from 0 to 10 ps by opening an ultrafast optical shutter based on a Kerr cell that is driven by a second synchronized laser pulse. This permits specific probing of different layers of tissue. Individual delayed spectra are co-added and the resulting correction signal is subtracted from the ungated composite spectrum or from late-arriving time-resolved spectra. We have validated this methodology using tissue from the metacarpus and radius of several strains of laboratory mice. Overlying skin, flesh and tendon was removed from metacarpus and radius of one foreleg of a mouse and the tissue used as a control. The other foreleg served as the test specimen and was prepared by shaving the hair from the tissue, leaving the skin intact. Transcutaneous time-gated Raman spectra were measured on these specimens. With an 800 nm laser spatially resolved spectroscopy with depth penetration to greater than 1 mm was easily achieved. Normal and defective bone tissue were readily distinguished.

Paper Details

Date Published: 28 April 2005
PDF: 7 pages
Proc. SPIE 5693, Optical Tomography and Spectroscopy of Tissue VI, (28 April 2005); doi: 10.1117/12.585457
Show Author Affiliations
Michael D. Morris, Univ. of Michigan (United States)
Edward R. C. Draper, Royal Veterinary College (United Kingdom)
Allen E. Goodship, Royal Veterinary College (United Kingdom)
Pavel Matousek, Rutherford Appleton Lab. (United Kingdom)
Michael Towrie, Rutherford Appleton Lab. (United Kingdom)
Anthony W. Parker, Rutherford Appleton Lab. (United Kingdom)
Nancy P. Camacho, Hospital for Special Surgery (United States)


Published in SPIE Proceedings Vol. 5693:
Optical Tomography and Spectroscopy of Tissue VI
Britton Chance; Robert R. Alfano; Bruce J. Tromberg; Mamoru Tamura; Eva M. Sevick-Muraca, Editor(s)

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