Inside of hollow
semisphere with central sphere

Outside of hollow semisphere with central sphere  
Two views of the numerical phantom  
Two views of reconstruction from four conebeam projections (tetrahedral arrangement)  
Two views of reconstruction from 18 randomdirection conebeam projections (2004: uniterated solution)  
Two views of
reconstruction from 18 randomdirection
conebeam projections (2005: solution iterated 3 more times) 