UCL Discovery

Abstract

Recent studies have demonstrated that image contrast in x-ray mammography could be enhanced by making use of both the transmitted and scattered radiation. At small angles coherently scattered photons undergo interference effects which can be used as a means of tissue characterisation. Several form factor data from x-ray diffraction measurements are now available We implemented these data in the EGS4 code so as to use realistic breast tissues (both tumour and healthy tissue) fora Monte Carlo simulation. A breast imaging system which makes use of a combined scatter/transmission signal has been modelled. Results of our simulation confirmed that the contrast between healthy and tumour tissue provided by small-angle scatter radiation is greater than that of primary image for object thicknesses of mammographic interest. Analysis of beam polychromaticity effects in coherent scattering showed that material discrimination is still possible with the conventional x-ray sources currently used. In the design of a diffraction enhanced breast imaging system signal-to-noise ratio performance must be considered in order to fully assess the increase in diagnostic capability effected by this approach.