Physical measurements have been made to determine image quality performance of an x-ray unit designed for conventional nonmagnification and magnation mammography using screen-film and xeroradiographic image recording systems. The unit has 2 focal spots: one for nonmagnification mammography and a microfocus spot for the magnification technique. The measurements include the geometric resolution at the extremes of focal spot-to-object distances of the breast for 1.5x magnification and for the nonmagnification technique. Unsharpness due to the image receptor and due to motion will be discussed relative to the geometric resolution. Half value layer and radiation dose measurements using both the nonmagnification and magnification techniques are presented for various kVp and filtration combinations. The effect of reciprocity law failure when screen-film systems are used for the magnification technique is also described. The tradeoff between radiation output and adequate "beam hardening" to maintain low patient exposure, an especially important consideration for this unit, is discussed. Conventional nonmagnification and magnification xeroradiegraphs are shown.

Date Published: 15 November 1978
PDF: 9 pages
Proc. SPIE 0152, Recent and Future Developments in Medical Imaging I, (15 November 1978); doi: 10.1117/12.938178

Published in SPIE Proceedings Vol. 0152:
Recent and Future Developments in Medical Imaging I
Norman A. Baily, Editor(s)