Influence of optical properties and fiber separation on laser doppler flowmetry

Larsson, Marcus; Steenbergen, Wiendelt; Strömberg, Tomas

doi:10.1117/1.1463049

Cited by 66 publications

(73 citation statements)

References 17 publications

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“…The most popular methods use different wavelengths (Koelink, De Mul et al 1994;Tulevski, Ubbink et al 1999) or different source-detector separations (Larsson, Steenbergen et al 2002). This study does not only show that changing the wavelength and/or source-detector separation has a major impact on the measurement depth, but also that changing tissue properties within relevant intervals has an effect on the measurement depth that is comparable with changing the system setup.…”

Section: (18)supporting

confidence: 57%

“…Previous studies have demonstrated a high correlation between Monte Carlo based simulations and LDF measurements (de Mul, Koelink et al 1995;Kienle, Patterson et al 1996;Larsson, Steenbergen et al 2002;Fredriksson, Larsson et al 2006;Larsson and Strömberg 2006). In this study, an in-house Monte Carlo software (Fredriksson, Larsson et al 2006;2008a;2008b) that tracks and stores information about each and every photon, including individual Doppler shifts, scattering positions, and photon weights, was used.…”

Section: Monte Carlo Simulationsmentioning

confidence: 99%

“…However, as they also state, that does not imply that 90 % of the perfusion value originates from the superficial plexus as the average velocity is higher for the inferior plexus. Larsson, Steenbergen et al (2002) investigated the effects on the optical path length and the sampling depth caused by the optical properties and the source-detector separation, using a sophisticated tissue phantom. It should be noted that the polystyrene spheres used as moving scatterers in that study scatters light much more diffusely than RBC:s, though.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Measurement depth and volume in laser Doppler flowmetry

Fredriksson

Larsson

Strömberg

2009

Microvascular Research

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Abstract:A new method for estimating the measurement depth and volume in laser Doppler flowmetry (LDF) is presented. The method is based on Monte Carlo simulations of light propagation in tissue. The contribution from each individual Doppler shift is calculated and thereby multiple Doppler shifts are handled correctly. Different LDF setups for both probe based (0.0, 0.25, 0.5, and 1.2 mm source-detector separation) and imaging systems (0.5 and 2.0 mm beam diameter) are considered, at the wavelengths 453 nm, 633 nm, and 780 nm. Non-linear speckle pattern effects are accounted for in the imaging system setups. The effects of tissue optical properties, blood concentration, and blood oxygen saturation are evaluated using both homogeneous tissue models and a layered skin model. The results show that the effect on the measurement depth of changing tissue properties is comparable to the effect of changing the system setup, e.g. sourcedetector separation and wavelength. Skin pigmentation was found to have a negligible effect on the measurement depth. Examples of measurement depths are (values are given for a probe based system with 0.25 mm source-detector separation and an imaging system with a 0.5 mm beam diameter, respectively, both operating at 780 nm): muscle -0.55/0.79 mm; liver -0.40/0.53 mm; gray matter -0.48/0.68 mm; white matter -0.20/0.20 mm; index finger pulp -0.41/0.53 mm; forearm skin -0.53/0.56 mm; heat provoked forearm skin -0.66/0.67 mm.

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Section: (18)supporting

confidence: 57%

Section: Monte Carlo Simulationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Measurement depth and volume in laser Doppler flowmetry

Fredriksson

Larsson

Strömberg

2009

Microvascular Research

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140

128

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“…The advantage of this approach is the absolute predictability of the results with Monte Carlo simulations. Larsson et al [70] used this system to assess the influence of tissue optical properties on the depth sensitivity and mean sampling depth of a laser Doppler perfusion monitor. All the above-mentioned models are more useful as research tools than as calibration devices for simple dayto-day use with the laser Doppler instrument.…”

Section: Calibration Standardsmentioning

confidence: 99%

Review of methodological developments in laser Doppler flowmetry

et al. 2008

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“…In general, the light interaction with tissue, and thus the measurement depth, is affected by several aspects such as probe design, light source and the tissue's scattering and absorption characteristics. Experimental investigations and Monte Carlo simulations show that the optical sampling depth in brain tissue is less than 1 mm [59,71,101]. Qian and colleagues [101] studied the "look ahead distance" in brain matter by means of Monte Carlo simulation and found that in the near infrared region and for small fiber separation, grey matter is expected to have a slightly increased "look ahead distance" than white matter.…”

Section: Optical Intracerebral Measurementsmentioning

confidence: 99%

Stereotactic implantation of deep brain stimulation electrodes: a review of technical systems, methods and emerging tools

Hemm¹,

Wårdell²

2010

Med Biol Eng Comput

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Deep brain stimulation (DBS) has become increasingly important for the treatment and relieve of neurological disorders such as Parkinson's disease, tremor, dystonia and psychiatric illness. As DBS implantations, and any other stereotactic and functional surgical procedure, require accurate, precise and safe targeting of the brain structure, the technical aids for preoperative planning, intervention and postoperative follow up have become increasingly important. The aim of this paper is to give an overview, from a biomedical engineering perspective, of a typical implantation procedure and current supporting techniques.Furthermore emerging technical aids not yet clinically established are presented. This includes the state-of-the-art of patient specific simulation of DBS electric field, optical methods for intracerebral guidance, movement pattern analysis, new stimulation devices and trends related to neuroimaging, visualization and navigation. As DBS surgery already today is an information technology intensive domain an "intuitive visualization" interface for improving management of these data in relation to surgery is suggested.

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Influence of optical properties and fiber separation on laser doppler flowmetry

Cited by 66 publications

References 17 publications

Measurement depth and volume in laser Doppler flowmetry

Measurement depth and volume in laser Doppler flowmetry

Review of methodological developments in laser Doppler flowmetry

Stereotactic implantation of deep brain stimulation electrodes: a review of technical systems, methods and emerging tools

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