*****   MONTCARL  *****

Monte-Carlo simulations of light transport in transparent or turbid media, like tissue,

with Scattering, Absorption, Fluorescence, Raman, Laser-Doppler and Photo-acoustics,

with layers and objects like spheres, tubes, cones, mirrors, lenses, pupils, diaphragms.

 

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Keywords:

 

MC transport-002Light  scattering and transport, with:

·         Events: scattering, absorption, reflection, refraction, transmission, absorption, cross sections and coefficients

·         Scattering functions: Mie, dipolar, Rayleigh, Gans, Henyey-Greenstein, Gegenbauer, or Isotropic, fluorescence, Raman-scattering,

·         Layers and objects: tubes, spheres, blocks, torusses, cones, mirrors

·         Ray tracking and Imaging through transparent and turbid lenses, pupils, diaphragms, mirrors….

·         Extra’s: frequency modulation, Doppler frequency, Laser-Doppler flowmetry, skin tissue, path tracking, flight tracking, Photo-Acoustic signal production.

·         Table of suggested optical properties in tissue.

 

MOVIES

 

randombollen1_2_000000317See MOVIES:                 (click left to play, or right to download, try VLC-player)

1. Full description of the program:  video : youtube movie  

2. Light scattering by particles, theoretical models and derivations:  pdf-file

          I. Light scattering theories and models:               video:  part I

          II. Derivations of dipolar and general scattering expressions:        video:  part II

3. The transport process of photons in the medium: video formats: MOV, MP4

System: 2 layers with scatterers, with random spheres in the 2nd layer.   See Figs 11...14 below.

               Solid (blue/green) tracks : in layers;     Dashed (red) tracks: in spheres.

General objective:

 

·         The program calculates Monte-Carlo simulations of LIGHT TRANSPORT IN TRANSPARENT OR TURBID MEDIA, WITH SCATTERING and/or ABSORPTION (optional: followed by FLUORESCENCE or RAMAN-scattering, or
PHOTOACOUSTICS) in turbid media, like tissue.

·         The SAMPLE may consist of a single or more LAYERS, each with its own absorption and scattering data, in the form of concentrations of scattering particles embedded in a medium.
In order to register DOPPLER spectra, to each type of scattering particle a certain velocity vector can be associated..
In each layer a number of separately defined structures (called "OBJECTS": with rectangular, cylindrical, spherical or conical shape) may be present, with similar characteristics as the layers. Option: spheres may be randomly distributed in a layer.
With those objects e.g. blood vessels can be mimicked. Also
transparent and turbid lenses and pupils /diaphragms….

·         Also an oblique mirror plane can be inserted.
Furthermore, the layers may be subdivided into sublayers (depth pixels, see below).

·         There are a number of options: internal light sources and external beams, internal and external detection, plots of distributions of various variables (photon positions, path length distributions, photon tracking, layer+object structure plots, frequency modulation by Fourier transformations, angular distributions, photo-acoustic response plots, ray tracking in lenses systems, ….

More information:

 

·         Description of the program options                                       

·         The physical mathematics behind the calculations                 

·         See also: List of publications                                                       

Options:

 

·         Download the full version of the program and work for yourself.

·         Let us do the simulations for you (first try-out free; contact us); this will save you a lot of work and time!

DOWNLOADS

 

·        For the full version (your first download):  Download montcarl.zzz here to a new or suitable folder.

·        After download: (1) change *.zzz -> *.zip, (2) unzip *.zip into that folder,

·        then (3) read “READ ME FIRST”  and (4) run MC_Install.exe. That program will install all necessary files.

 

·        For updates: Download montcarl_update.zzz from here to your MONTCARL\PROG-folder;

·        then: (1) change *.zzz -> *.zip; (2) unpack *.zip into that folder; (3) change *.fff -> *.exe and (4) run *.exe-file..

 

Examples of screens in the program:

All screen outputs with results also have print and file output in table format, compatible with Excel-like programs.

 

Fig. 1. Begin screen of the program (choice of screen size and color)

Fig. 2. Menu screen (with Tabs)

MC-menu2

 

Fig. 3. Overview about how to input settings and to run simulations

 

Fig. 4. Creation of scattering functions (called: *.MIE-files)

MC-overview

 

Fig.5. A scattering pattern (combination: Mie + Henyey-Greenstein-functions)

 

↓ Fig.6. Selection of scattering functions for use in layers and objects

MC-scatplot

MC-scatt2

 

Fig.7. Input of data for the light source (e.g. laser data)

 

Fig. 8. Input of data for layers (more than 1 layer possible)

MC-laser2

MC-layers

 

Fig. 9. Input of data for objects (spheres, tubes, mirrors, cones, blocks…)

 

Fig. 10. Detection, calculation mode, flight and path tracking and output

MC-objects

MC-detout2

 

Fig. 11. Structure of the layer system with 1 layer and 1 tube in Y-direction

 

Fig. 12. Simulation of the structure of Fig. 11. View // Y-axis (XZ-plane)

MC-struct-tube

MC-run-tube

 

Fig. 13. Structure of a single layer with random spheres

 

Fig.14. Simulation of the structure of Fig. 13. View // Z-axis (XY-plane)

MC-struct-randbol

MC-run-randbol

 

Fig. 15. Path tracking for selected points of emergence. Single layer

 

Fig. 16. Path tracking of Fig. 15: crossings with predefined planes; 1 layer.

MC-paths

MC-crossings

 

↓Fig. 17. Plot options: choice of axes (“intensity” if vert.axis = none)

 

↓ Fig.18. Plot  options: settings for an intensity plot

MC-plot1

MC-plot2

 

Fig. 19. Intensity plot, with model fitting. Plots of >1 runs optional (with shifts).

 

Fig. 20. Scatter plot of results. Plots of >1 runs optional (with vert./hor. shifts)

MC-res-intens-plot

MC-res-scatt-plot

 

Fig. 21. 2D-plot of results: total number of re-emerging photons.

 

Fig.22. 2D-plot of results: average scattering depth of all photons.

MC-2d-averdep

 

Fig. 23. Photo-acoustic response of absorbed photons: settings

 

Fig. 24. Photo-acoustic response in 10x10–detector array of 1 tube (Fig.11)

MC-pats1

MC-plot2

 

Fig. 25. Extra: frequency modulation of GHz-signals in tissue layers.

 

↓ Fig. 26. Imaging through a thick convex-concave lens with a few scatterers

MC-freqmod