Optical properties of tissue, experimental results (Or: The influence of lung volume on the optical properties of in vitro piglet lung at 632.8 nm)

The effectivc attenuation coefficient of piglet lung was measured in vitro at 632.8 nm. Interstial fibres with isotropic tips were used to measure the fluence rate as a function of the distance from an isotropic light source. In vitro measurements at 632.8 nm on a lung that was insufflated with oxygen from 50 to 150 ml showed that the cffcctivc attenuation coefficient decreases as a function of the volume of air in the lung (at 50 ml [1 - - 0.297 ±0.011 mm-1, at 100 ml μeff= 0.150 ± 0.007 mm-1, and at 150 ml μeff= 0.136 +. 0.015 mm-1). A single in vitro measurement at 790 nm at an insufflated lung volume of 100 ml gave a comparable result (μeff = 0.175 +. 0.004 mm-1). A decrease in effective attenuation coefficient with an increase in lung volume was explained by Mie-theory. The effective attenuation coefficient, calculated with μs and g from Mie-theory, showed a deviation < 22% from the measured in vitro values.

• View at Publisher
• View at Scopus