*****   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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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.




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                                                       



·         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!



·        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)



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


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



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


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




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)




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


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




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)




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


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




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


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




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


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




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)




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


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



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


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




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


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