  A multi-prism lens (MPL) is a refractive x-ray lens with one-dimensional
focusing properties. If used as a pre-object collimator in a scanning system
for medical x-ray imaging, it reduces the divergence of the radiation and
improves on photon economy compared to a slit collimator. Potential advantages
include shorter acquisition times, a reduced tube loading, or improved
resolution. We present the first images acquired with an MPL in a prototype for
a scanning mammography system. The lens showed a gain of flux of 1.32 compared
to a slit collimator at equal resolution, or a gain in resolution of 1.31-1.44
at equal flux. We expect the gain of flux in a clinical set-up with an
optimized MPL and a custom-made absorption filter to reach 1.67, or 1.45-1.54
gain in resolution.
