The optical properties of lung as a function or respiration

J.F. Beek, H.J. Staveren, P. Posthumus, H.J.C.M. Sterenborg, M.J.C. van Gemert

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Abstract

Lung consists of alveoli enclosed by tissue and both structures contribute to volume-dependent scattering of light. It is the purpose of this paper to determine the volume-dependent optical properties of lung. In vivo interstitial fibre measurements of the effective attenuation coefficient mu eff at 632.8 nm differed during inspiration (mu eff = 2.5 +/- 0.5 cm-1) from that during expiration (mu eff = 3.2 +/- 0.6 cm-1). In vitro measurements on a piglet lung insufflated with oxygen from 50 to 150 ml showed the effective attenuation coefficient at 632.8 nm decreases as a function of oxygen volume in the lung (at 50 ml mu eff = 2.97 +/- 0.11 cm-1, at 100 ml mu eff = 1.50 +/- 0.07 cm-1, and at 150 ml mu eff = 1.36 +/- 0.15 cm-1). This was explained by combining scattering of alveoli (Mie theory) with optical properties of collapsed lung tissue using integrating sphere measurements. Theory and measured in vitro values showed good agreement (deviation < or = 15%). Combination of these data yields the absorption coefficient and scattering parameters of lung tissue as a function of lung volume. We conclude that the light fluence rate in lung tissue should be estimated using optical properties that include scattering by the alveoli
Original languageUndefined/Unknown
Pages (from-to)2263-2272
JournalPhysics in Medicine and Biology
Volume42
Issue number11
DOIs
Publication statusPublished - 1997

Keywords

  • AMC wi-eigen

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