Publications [#132812] of G. Allan Johnson

Papers Published
  1. GA Johnson, F O'Foghludha, Simulation of mammographic x-ray spectra., Medical physics, UNITED STATES, vol. 7 no. 3 , pp. 189-95 .

    Attempts to simulate Mo-anode spectra for film mammography by using Mo filters with W-anode tubes have been reported by several workers, and others have generated W-like continua for xeromammographic purposes by heavy Al filtration of Mo-anode tubes. In the present work the success of these simulations was tested by Si(Li) spectrometric methods that measured the spectral shapes and the exposure levels. Comparisons of Mo-anode/Al-filter with W-anode/Al-filter combinations were made, and also of W-anode/M-filter with Mo-anode/Mo-folter combinations. In certain circumstance the spectral shape is moderately well simulated but in all cases the useful output is less in the simulations than in the original spectra. The general conclusion is that simulation is always less attractive than direct use of the desired anode.