How can I calculate point spread function?

Hi ,
I simulated SPECT camera using Gate. I want to calculate and plot point spread function(psf) from root output (.root file) of Gate simulation. For doing this work I need .C file which calculate a psf. I need the commends ( orders) in .C file that compute the point spread function and then plot it . what are the necessary comments for computing the point spread function in .C file?
Would you please help me?

Hi,

you posted the same questions on all categories of the forum. I took the freedom to purge all but one posts: this strategy does not increase the likelihood of being better helped out.
It is hard to understand what you want to achieve from your text. Perhaps you can start from a general introduction to ROOT in order to be able to solve your particular problem. You can certainly have a look here to start: root.cern.ch/getting-started

Cheers,
D