Radiation protection from natural radionuclides

Greetings experts
I am new to Geant4 and am interested in simulation of deposited energy in water cylinder at center of a room with walls having high levels of natural radionuclides Ra-226, Th-232 and K-40 for purposes of determining gamma absorbed dose to human in the same room. What would be the relevant Geant4examples that would relate to this work. Thank you.

extended/radioactivedecay is a good place to start

Thank you so much for the guidance