EDXRS modelling for in vivo trace element analysis by using the SHAPE code

The validity of the SHAPE code, a computer package able to simulate EDXRS spectra, was tested to model the in vivo XRF determination of cadmium concentrations in the kidney by choosing the best source–measurement geometry combination. Accurate measurements were performed in order to validate the results of this code in the energy interval involved in in vivo XRF analysis. In addition, a comparison was made with Monte Carlo results including thrid-order contributions and polarization. Very good agreement was found with the experimental and Monte Carlo results. In spite of the fact that, at present, this code does not include higher order multiple scattering, modelling results using the SHAPE code agree very well with the expensive Monte Carlo solutions and the empirical values recently predicted for this technique.