Assessment of near-infrared path length in fibrous phantom and muscle tissue.
The first derivative of the pseudo-absorption spectrum of a water-loaded cotton wool (water-CW) phantom, which mimics muscle tissues, was used to determine the light path length in the near-infrared (NIR) region. The light path length increased as the density of the turbid medium decreased. It is independent of both water content in the range of 75-85% (by weight) and the diffuse reflecting reference used to determine the pseudo-absorbance. The path length determination procedure was verified by measurements of diffuse reflectance in chicken breast tissue for which the path length of 1.8 mm (differential path length factor, DPF = 2.1) was found to be similar to the path length of NIR light of 1.5-2.2 mm (DPF = 1.8-2.6) in a water-CW phantom of density similar to chicken breast. We conclude that the NIR light path length can serve as a characteristic of muscle tissue density.
Gussakovsky
Eugene
E
Institute for Biodiagnostics, National Research Council Canada, Winnipeg, Canada.
Kupriyanov
Valery
V
D000818:Animals; D018482:Muscle, Skeletal / Q000737:chemistry*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017550:Spectroscopy, Fourier Transform Infrared / Q000295:instrumentation* / Q000379:methods*; D014935:Wool / Q000737:chemistry*