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Effect of probe geometry on transsceral diffuse optical spectroscopy

Svenmarker, Pontus LU ; Xu, Can LU ; Andersson-Engels, Stefan LU and Krohn, Jørgen (2011) In Biomedical Optics Express 2(11). p.3058-3071
Abstract
The purpose of this study was to investigate how the geometry of a fiber optic probe affects the transmission and reflection of light through the scleral eye wall. Two geometrical parameters of the fiber probe were investigated: the source-detector distance and the fiber protrusion, i.e. the length of the fiber extending from the flat surface of the fiber probe. For optimization of the fiber optic probe geometry, fluorescence stained choroidal tumor phantoms in ex vivo porcine eyes were measured with both diffuse reflectance- and laser-induced fluorescence spectroscopy. The strength of the fluorescence signal compared to the excitation signal was used as a measure for optimization. Intraocular pressure (IOP) and temperature were monitored... (More)
The purpose of this study was to investigate how the geometry of a fiber optic probe affects the transmission and reflection of light through the scleral eye wall. Two geometrical parameters of the fiber probe were investigated: the source-detector distance and the fiber protrusion, i.e. the length of the fiber extending from the flat surface of the fiber probe. For optimization of the fiber optic probe geometry, fluorescence stained choroidal tumor phantoms in ex vivo porcine eyes were measured with both diffuse reflectance- and laser-induced fluorescence spectroscopy. The strength of the fluorescence signal compared to the excitation signal was used as a measure for optimization. Intraocular pressure (IOP) and temperature were monitored to assess the impact of the probe on the eye. For visualizing any possible damage caused by the probe, the scleral surface was imaged with scanning electron microscopy after completion of the spectroscopic measurements. A source-detector distance of 5 mm with zero fiber protrusion was considered optimal in terms of spectroscopic contrast, however, a slight fiber protrusion of 0.5 mm is argued to be advantageous for clinical measurements. The study further indicates that transscleral spectroscopy can be safely performed in human eyes under in vivo conditions, without leading to an unacceptable IOP elevation, a significant rise in tissue temperature, or any visible damage to the scleral surface. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
diffusion, Scattering, fluorescence and luminescence, tissue diagnostics, Spectroscopy, Medical optics instrumentation, visible
in
Biomedical Optics Express
volume
2
issue
11
pages
3058 - 3071
publisher
Optical Society of America
ISSN
2156-7085
language
English
LU publication?
yes
id
c29b212b-9603-4394-8b33-9980dcaa1ac7 (old id 2172702)
date added to LUP
2011-10-11 14:44:54
date last changed
2016-04-16 08:46:25
@article{c29b212b-9603-4394-8b33-9980dcaa1ac7,
  abstract     = {The purpose of this study was to investigate how the geometry of a fiber optic probe affects the transmission and reflection of light through the scleral eye wall. Two geometrical parameters of the fiber probe were investigated: the source-detector distance and the fiber protrusion, i.e. the length of the fiber extending from the flat surface of the fiber probe. For optimization of the fiber optic probe geometry, fluorescence stained choroidal tumor phantoms in ex vivo porcine eyes were measured with both diffuse reflectance- and laser-induced fluorescence spectroscopy. The strength of the fluorescence signal compared to the excitation signal was used as a measure for optimization. Intraocular pressure (IOP) and temperature were monitored to assess the impact of the probe on the eye. For visualizing any possible damage caused by the probe, the scleral surface was imaged with scanning electron microscopy after completion of the spectroscopic measurements. A source-detector distance of 5 mm with zero fiber protrusion was considered optimal in terms of spectroscopic contrast, however, a slight fiber protrusion of 0.5 mm is argued to be advantageous for clinical measurements. The study further indicates that transscleral spectroscopy can be safely performed in human eyes under in vivo conditions, without leading to an unacceptable IOP elevation, a significant rise in tissue temperature, or any visible damage to the scleral surface.},
  author       = {Svenmarker, Pontus and Xu, Can and Andersson-Engels, Stefan and Krohn, Jørgen},
  issn         = {2156-7085},
  keyword      = {diffusion,Scattering,fluorescence and luminescence,tissue diagnostics,Spectroscopy,Medical optics instrumentation,visible},
  language     = {eng},
  number       = {11},
  pages        = {3058--3071},
  publisher    = {Optical Society of America},
  series       = {Biomedical Optics Express},
  title        = {Effect of probe geometry on transsceral diffuse optical spectroscopy},
  volume       = {2},
  year         = {2011},
}