What sort of particles are we talking about?  Would they be reflected only precisely at the surface or are they reflected by collisions within the tissue?  If the latter then tallying particles crossing the surface back toward the source could be considered as "reflected"

Hi

I advice you to see these documents. You will find what you need.

Best regards

http://omlc.org/software/mc/

http://www.diss.fu-berlin.de/diss/servlets/MCRFileNodeServlet/FUDISS_derivate_000000001355/05_kap4.pdf;jsessionid=0EF781B66539D13FBA58204361E50E05?hosts=

https://www.google.fr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0CEoQFjAEahUKEwiW4NKPu8TIAhWB0RoKHQdyArU&url=http%3A%2F%2Fwww.opengatecollaboration.org%2Fsites%2Fopengatecollaboration.org%2Ffiles%2FCuplov2014.pdf&usg=AFQjCNFkW6SlSU8sF21vUgoEUFfv0Ru5Hg&sig2=PJAw532Cg4X1srUtmdViKA&bvm=bv.105039540,d.d2s

Hi Ahmed,

I have already read http://omlc.org/software/mc/ and similar sources but don't fully understand as I am new to field. So looking forward a more straight forward guidance.

Thank you.

There are discrete issues. The first is the radiation transport in a detector. The second is the light that the absorption of the radiation produces. This can be rather complicated since different models are applicable to scintillators, semiconductors etc. Third is to if one employs an analytical optical model. In the latter case, coefficients are needed one of which is the one of the reflection.

If you use packages like MCML or TIM-OS for MC simulation, they have reflectance data sets as well as fluence map. you should use .mco ASCII file produced as output after simulation is done.

regards,