LightSpread is a tool based on a Monte Carlo simulation of photon transport in turbid medium. Within the limits of the assumption of uniform medium around the light source, results returned by LightSpread are a reasonable estimation of how the light emitted by a flat-cleaved or a tapered fiber propagates in the brain tissue.

LightSpread photons propagation engine derives from MCML software (L. Wang et al., Computer Methods and Programs in Biomedicine 47(2), 131 (1995), https://omlc.org/software/mc/mcml/index.html) and from the work by J. M. Stujenske et al., Cell Reports 12(3), 525 (2015).

Other references were I. Lux, L. Koblinger, Monte Carlo Particle Transport Methods: Neutron and Photon Calculations. Boca Raton, CRC Press (1991); D. W. O. Rogers, A. F. Bielajew. Monte Carlo Techniques of Electron and Photon Transport for Radiation Dosimetry. In "The Dosimetry of Ionizing Radiation" Volume III, edited by K. R. Kase, B. E. Bjärngard, F. H. Attix, Academic Press (1990).

Default optical parameters for wavelengths 405nm, 473nm, 561nm, and 635nm are extrapolated from data reported in J. D. Johansson, Journal of Biomedical Optics 15(5), 057005 (2010) and J. Binding et al., Optics Express 19(6), 4833-4847 (2011).

Please contact OptogeniX at info@optogenix.com for more information regarding LightSpread.


----- Minimum requirements -----
Operating system: Windows 10 x64
Memory: 8GB RAM
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----- Tips -----
1. Wavelength selection allow to use a preset of tissue scattering parameters. If these parameters are selected by the user, the wavelength value will not affect the simulation.

2. Launching 10 packets of 100000 photons each is usually a reasonable tradeoff between running time and accuracy of the results.

3. A gaussian smoothing can be applied to the results by checking the LPF checkbox; the filter order can be specified with an odd integer number.

4. When the Log scale checkbox is checked, results will be visualized with a logarithmic colorbar.

5. The zoom tool can be used to select a portion of the colormap.

6. At the end of the simulation LightSpread shows the average power density emitted by the fiber. This value correspond to the total emitted power divided by the area of the emitter (i.e. the lateral surface of the cone for tapered fibers or the circle surface for flat fibers).
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