Objective comparison of image quality and dose between conventional and synchrotron radiation mammography

The shape of the energy spectrum produced by an x-ray tube has a great impo rtance in mammography. Many anode-filtration combinations have been propose d to obtain the most effective spectrum shape for the image quality-dose re lationship. On the other hand, third generation synchrotrons such as the Eu ropean Synchrotron Radiation Facility in Grenoble are able to produce a hig h flux of monoenergetic radiation. It is thus a powerful tool to study the effect of beam energy on image quality and dose in mammography. An objective method was used to evaluate image quality and dose in mammogra phy with synchrotron radiation and to compare them to standard conventional units. It was performed systematically in the energy range of interest for mammography through the evaluation of a global image quality index and thr ough the measurement of the mean glandular dose. Compared to conventional m ammography units, synchrotron radiation shows a great improvement of the im age quality-dose relationship, which is due to the beam monochromaticity an d to the high intrinsic collimation of the beam, which allows the use of a slit instead of an anti-scatter grid for scatter rejection.