title: Determination of visible near-IR absorption coefficients of mammalian fat using time- and spatially resolved diffuse reflectance and transmission spectroscopy.
abstract: In-vivo optical spectroscopy and the determination of tissue absorption and scattering properties have a central role in the development of novel optical diagnostic and therapeutic modalities in medicine. A number of techniques are available for the optical characterization of tissue in the visible near-IR region of the spectrum. An important consideration for many of these techniques is the reliability of the absorption spectrum of the various constituents of tissue. The availability of accurate absorption spectra in the range 600 to 1100 nm may allow for the determination of the concentration of key tissue constituents such as oxy- and deoxy-hemoglobin, water, and lipids. The objective of the current study is the determination of a reliable absorption spectrum of lipid(s) that can be used for component analysis of in-vivo spectra. We report the absorption spectrum of a clear purified oil obtained from pig lard. In the liquid phase above 36 degrees C, the oil is transparent and thus suitable for collimated transmission measurements. At room temperature, the oil is a solid grease that is highly scattering. The absorption and scattering properties in this solid phase are measured using time- and spatially resolved diffuse reflectance spectroscopy. Using these three independent measurement techniques, we have determined an accurate estimate for the absorption spectrum of mammalian fat.
authors.affiliation: Erasmus Medical Center Rotterdam, Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Westzeedijk 118, 3008 CA, The Netherlands.
authors.forename: R L P
authors.initials: RL
authors.lastname: van Veen
authors.forename: H J C M
authors.initials: HJ
authors.lastname: Sterenborg
authors.forename: A
authors.initials: A
authors.lastname: Pifferi
authors.forename: A
authors.initials: A
authors.lastname: Torricelli
authors.forename: E
authors.initials: E
authors.lastname: Chikoidze
authors.forename: R
authors.initials: R
authors.lastname: Cubeddu
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry*; D000818:Animals; D004041:Dietary Fats / Q000032:analysis*; D009821:Oils / Q000032:analysis*; D012031:Refractometry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013055:Spectrophotometry, Infrared / Q000379:methods*; D013552:Swine
chemical_list: D004041:Dietary Fats; D009821:Oils; C029310:lard