Optical Properties of Circulating Human Blood in the Wavelength Range 400–2500 nm

Abstract

Knowledge about the optical properties μa,μs, and g of human blood plays an important role for many diagnostic and therapeutic applications in laser medicine and medical diagnostics. They strongly depend on physiological parameters such as oxygen saturation, osmolarity, flow conditions, haematocrit, etc. The integrating sphere technique and inverse Monte Carlo simulations were applied to measure μa,μs, and g of circulating human blood. At 633 nm the optical properties of human blood with a haematocrit of 10% and an oxygen saturation of 98% were found to be 0.210±0.002 mm-1 for μa,77.3±0.5 mm-1 for μs, and 0.994±0.001 for the g factor. An increase of the haematocrit up to 50% lead to a linear increase of absorption and reduced scattering. Variations in osmolarity and wall shear rate led to changes of all three parameters while variations in the oxygen saturation only led to a significant change of the absorption coefficient. A spectrum of all three parameters was measured in the wavelength range 400-2500 nm for oxygenated and deoxygenated blood, showing that blood absorption followed the absorption behavior of haemoglobin and water. The scattering coefficient decreased for wavelengths above 500 nm with approximately λ-1.7; the g factor was higher than 0.9 over the whole wavelength range. © 1999 Society of Photo-Optical Instrumentation Engineers.

Oxygen Saturation-Dependent Absorption and Scattering of Blood

“…These, however, do not change the shape of the presented curves, only their amplitude. For low H, our calculated data show good agreement with the experimental optical data of oxygenated diluted blood by Roggan et al measured using a double integrating sphere technique [25]. However, contrary to our results, variations of scattering coefficient and anisotropy with SO 2 did not reach significance.…”

“…However, an increase in g with wavelength was found. The highly forward scattering of blood, with g reported between 0.985 and 0.997 [23,[23][24][25][26][27], makes it difficult to separate scattered from nonscattered light, e.g., required in integrating sphere measurements, implying that the optical properties of whole blood are difficult to determine experimentally. Moreover, aggregation and biochemical responses, such as clotting, make it especially challenging to perform measurements of ex vivo whole blood samples under controlled physiological conditions.…”

“…Moreover, aggregation and biochemical responses, such as clotting, make it especially challenging to perform measurements of ex vivo whole blood samples under controlled physiological conditions. Extraction of optical properties from such measurements is complex, and usually requires an inverse Monte Carlo technique [25,26]. Consequently, a wide variety of experimental values have been reported [16,23,[25][26][27].…”

Gold Nanorod-assisted Optical Stimulation of Neuronal Cells

“…The stimulatory effect of the 780 nm laser diode observed during the experiments was not linked to heat generated by water absorption, as this is known to be negligible at 780 nm 36 . Previously published results have also reported stimulatory effects of 780 nm light on neuronal tissue in vivo 37,38 .…”

Detection of Human Skin in Near Infrared Hyperspectral Imagery

“…well as water in the blood are assumed to affect all aspects of the model. Blood in the skin is assumed to be made up of 85% water with no other significant absorbers or scatters in the NIR [8]. The absorption coefficients for the skin tissue layers, where n is the layer index, are shown in Eqn.…”