Changes in Optical Properties of Human Whole Blood in vitro Due to Slow Heating

Optical properties of human whole blood were investigated in vitro at 633 nm using a double integrating sphere set‐up. The blood flow was maintained at a constant rate through a flow cell while continuously heating the blood at 0.2–1.lC/min from approximately 25 to 55°C in a heat exchanger. A small, but rather abrupt decrease in the scattering asymmetry factor (g‐factor) of 1.7 ± 0.6% and a similar increase in the scattering coefficient of 2.9 ± 0.6% were observed at approximately 45–46°C yielding an increase in the reduced scattering coefficient of 40 ± 10%. Furthermore, a continuous, manifest increase in the absorption coefficient was seen with increasing temperature, on average 80 ± 70% from 25 to 50°C. The effect of the heating on the blood cells was also studied under a white‐light transmission microscope. A sudden change in the shape of the red blood cells, from discshaped to spherical, was observed at approximately the same temperature at which the distinct changes in g‐factor and scattering coefficient were observed, i.e. at 45–46°C. The results indicate that this shape transformation could explain the sudden change in scattering properties.

[1]  H. Karle,et al.  Effect on Red Cells of a Small Rise in Temperature: in Vitro Studies , 1969, British journal of haematology.

[2]  S Andersson-Engels,et al.  Effects of optical constants on time-gated transillumination of tissue and tissue-like media. , 1992, Journal of photochemistry and photobiology. B, Biology.

[3]  A. Welch,et al.  A review of the optical properties of biological tissues , 1990 .

[4]  B. Wilson,et al.  Frequency-domain reflectance for the determination of the scattering and absorption properties of tissue. , 1991, Applied optics.

[5]  G. Murphy,et al.  Ultrastructural changes in red blood cells following pulsed irradiation in vitro. , 1989, The Journal of investigative dermatology.

[6]  W Verkruysse,et al.  Modelling light distributions of homogeneous versus discrete absorbers in light irradiated turbid media. , 1997, Physics in medicine and biology.

[7]  S B Shohet,et al.  Effects of heat and metabolic depletion on erythrocyte deformability, spectrin extractability and phosphorylation. , 1978, Progress in clinical and biological research.

[8]  D E Green,et al.  Membrane structure. , 1971, Science.

[9]  A H Gandjbakhche,et al.  Light-scattering technique for the study of orientation and deformation of red blood cells in a concentrated suspension. , 1994, Applied optics.

[10]  Hoffman Jf.  On the mechanism and measurement of shape transformations of constant volume of human red blood cells. , 1987 .

[11]  J W Pickering,et al.  Changes in the optical properties (at 632.8 nm) of slowly heated myocardium. , 1993, Applied optics.

[12]  P. Ake Oberg,et al.  Optical properties of blood in motion , 1992, Photonics West - Lasers and Applications in Science and Engineering.

[13]  S. Thomsen.  PATHOLOGIC ANALYSIS OF PHOTOTHERMAL AND PHOTOMECHANICAL EFFECTS OF LASER–TISSUE INTERACTIONS , 1991, Photochemistry and photobiology.

[14]  A. P. Shepherd,et al.  Comparison of Mie theory and the light scattering of red blood cells. , 1988, Applied optics.

[15]  Lothar Lilge,et al.  Temperature-dependent changes in the optical absorption and scattering spectra of tissues: correlation with ultrastructure , 1993, Photonics West - Lasers and Applications in Science and Engineering.

[16]  R.R. Anderson,et al.  Selective photothermolysis: precise microsurgery by selective absorption of pulsed radiation. , 1983, Science.

[17]  H. Ducoff,et al.  Effects of hyperthermia on avian red blood cells. , 1993, International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group.

[18]  B. Wilson,et al.  A diffusion theory model of spatially resolved, steady-state diffuse reflectance for the noninvasive determination of tissue optical properties in vivo. , 1992, Medical physics.

[19]  J. Pickering,et al.  Double-integrating-sphere system for measuring the optical properties of tissue. , 1993, Applied optics.

[20]  W Verkruysse,et al.  Light distributions in a port wine stain model containing multiple cylindrical and curved blood vessels , 1996, Lasers in surgery and medicine.

[21]  Lihong V. Wang,et al.  Monte Carlo Modeling of Light Transport in Multi-layered Tissues in Standard C , 1992 .

[22]  A. Welch,et al.  Determining the optical properties of turbid mediaby using the adding-doubling method. , 1993, Applied optics.

[23]  T. Kitai,et al.  Contribution of the mitochondrial compartment to the optical properties of the rat liver: a theoretical and practical approach. , 1994, Biophysical journal.

[24]  M. Frojmovic,et al.  Blood cell structure-function studies: light transmission and attenuation coefficients of suspensions of blood cells and model particles at rest and with stirring. , 1975, The Journal of laboratory and clinical medicine.

[25]  S Andersson-Engels,et al.  A mathematical model for predicting the temperature distribution in laser-induced hyperthermia. Experimental evaluation and applications. , 1995, Physics in medicine and biology.

[26]  O'Neill Barrett,et al.  Living Blood Cells and Their Ultrastructure , 1975 .