Phantom equivalent thicknesses in diagnostic radiology

Some measurements in diagnostic radiology must be done with phantoms. The most frequently used phantoms are water, plexiglass, aluminium and copper. It is interesting to know the equivalent thicknesses between these phantoms in order to be able to relate these values to real anatomical organs of known thicknesses. The use of antiscatter grids, the choice of intensifier screens, the beam size and in general the scattering parameters considerably change the equivalent thicknesses. Many situations have been simulated by the Monte Carlo method and equivalent thicknesses are presented.