Linked Life Data

11954713

Source:http://linkedlifedata.com/resource/pubmed/id/11954713

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2002-4-16
pubmed:abstractText
Laser Doppler perfusion monitoring and imaging technologies generate time traces and two-dimensional flow maps of the microcirculation. With the goal of reaching different tissue depths, these technologies are equipped with lasers operating at different wavelengths lambda. The fact that the average scattering angle, at a single scattering event, between a photon and a red blood cell increases with lambda is compensated for by a 1/lambda effect in the scattering vector, rendering the average frequency shift virtually independent of the choice of wavelength. Monte Carlo simulations showed that the corresponding spectral signature of the Doppler signals for lambda = 632.8 nm and 780 nm were close to identical. The theoretical predictions were verified by calculating the centre-of-gravity (COG) frequency of the laser Doppler power spectral density for the two wavelengths from forearm and finger skin, representing a low and high perfusion area, respectively (forearm COG= 123 against 121 Hz, finger COG = 220 against 212 Hz). When the wavelength changes from 632.8 nm to 780 nm, the heterodyne efficiency of the detector and, thereby, the inherent system amplification increase. For tissues with identical microvascular flow conditions, the output signal therefore tends to increase in magnitude when shifting to longer wavelengths.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0140-0118
pubmed:author
pubmed:issnType
Print
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
85-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Spectral signature and heterodyne efficiency for different wavelengths in laser Doppler flowmetry.
pubmed:affiliation
Department of Biomedical Engineering, Linköping Universitet, Sweden.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't