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- Alanentalo, Tomas, et al.
(författare)
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High-resolution three-dimensional imaging of islet-infiltrate interactions based on optical projection tomography assessments of the intact adult mouse pancreas
- 2008
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Ingår i: Journal of Biomedical Optics. - Bellingham, WA : SPIE--the International Society for Optical Engineering. - 1083-3668 .- 1560-2281. ; 13:5, s. 054070-
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Tidskriftsartikel (refereegranskat)abstract
- A predicament when assessing the mechanisms underlying the pathogenesis of type-1 diabetes (T1D) has been to maintain simultaneous global and regional information on the loss of insulin-cell mass and the progression of insulitis. We present a procedure for high-resolution 3-D analyses of regions of interest (ROIs), defined on the basis of global assessments of the 3-D distribution, size, and shape of molecularly labeled structures within the full volume of the intact mouse pancreas. We apply a refined protocol for optical projection tomography (OPT)-aided whole pancreas imaging in combination with confocal laser scanning microscopy of site-directed pancreatic microbiopsies. As such, the methodology provides a useful tool for detailed cellular and molecular assessments of the autoimmune insulitis in T1D. It is anticipated that the same approach could be applied to other areas of research where 3-D molecular distributions of both global and regional character is required.
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| 2. |
- Alerstam, Erik, et al.
(författare)
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Parallel computing with graphics processing units for high-speed Monte Carlo simulation of photon migration.
- 2008
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Ingår i: Journal of Biomedical Optics. - : SPIE-Intl Soc Optical Eng. - 1083-3668. ; 13:6
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Tidskriftsartikel (refereegranskat)abstract
- General-purpose computing on graphics processing units (GPGPU) is shown to dramatically increase the speed of Monte Carlo simulations of photon migration. In a standard simulation of time-resolved photon migration in a semi-infinite geometry, the proposed methodology executed on a low-cost graphics processing unit (GPU) is a factor 1000 faster than simulation performed on a single standard processor. In addition, we address important technical aspects of GPU-based simulations of photon migration. The technique is expected to become a standard method in Monte Carlo simulations of photon migration.
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| 3. |
- Alerstam, Erik, et al.
(författare)
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White Monte Carlo for time-resolved photon migration.
- 2008
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Ingår i: Journal of Biomedical Optics. - : SPIE-Intl Soc Optical Eng. - 1083-3668. ; 13:4
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Tidskriftsartikel (refereegranskat)abstract
- A novel scheme for fully scalable White Monte Carlo (WMC) has been developed and is used as a forward solver in the evaluation of experimental time-resolved spectroscopy. Previously reported scaling problems are avoided by storing detection events individually, turning spatial and temporal binning into post-simulation activities. The approach is suitable for modeling of both interstitial and noninvasive settings (i.e., infinite and semi-infinite geometries). Motivated by an interest in in vivo optical properties of human prostate tissue, we utilize WMC to explore the low albedo regime of time-domain photon migration--a regime where the diffusion approximation of radiative transport theory breaks down, leading to the risk of overestimating both reduced scattering (mu(s)') and absorption (mu(a)). Experimental work supports our findings and establishes the advantages of Monte Carlo-based evaluation.
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| 10. |
- Antonsson, Johan, et al.
(författare)
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Radio frequency electrode system for optical lesion size estimation in functional neurosurgery
- 2005
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Ingår i: Journal of Biomedical Optics. - : SPIE - International Society for Optical Engineering. - 1083-3668 .- 1560-2281. ; 10:3, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- Radiofrequency(RF) lesioning in the human brain is one possible surgicaltherapy for severe pain as well as movement disorders. Oneobstacle for a safer lesioning procedure is the lack ofsize monitoring. The aim of this study was to investigateif changes in laser Doppler or intensity signals could beused as markers for size estimation during experimental RF lesioning.A 2 mm in diameter monopolar RF electrode was equippedwith optical fibers and connected to a digital laser Dopplersystem. The optical RF electrode's performance was equal to astandard RF electrode with the same dimensions. An albumin solutionwith scatterers was used to evaluate the intensity and laserDoppler signal changes during lesioning at 70, 80, and 90 °C.Significant signal changes were found for these three different clotsizes, represented by the temperatures (p<0.05, n=10). The volume, width, andlength of the created coagulations were correlated to the intensitysignal changes (r=0.88, n=30, p<0.0001) and to the perfusion signalchanges (r=0.81, n=30, p<0.0001). Both static and Doppler-shifted light canbe used to follow the lesioning procedure as well asbeing used for lesion size estimation during experimental RF lesioning.
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