Nico Lanconelli PhD, Abstract Co-Author: Nothing to Disclose

Stefano Rivetti MPH, Presenter: Research Consultant, FMSI

Marco Bertolini, Abstract Co-Author: Nothing to Disclose

Gianni Borasi, Abstract Co-Author: Nothing to Disclose

Paola Golinelli, Abstract Co-Author: Nothing to Disclose

Andrea Nitrosi PhD, Presenter: Nothing to Disclose

Ennio Gallo, Abstract Co-Author: Nothing to Disclose

Bruno Donini, Abstract Co-Author: Nothing to Disclose

Tiziana Costi, Abstract Co-Author: Nothing to Disclose

Luca Nocetti PhD, Abstract Co-Author: Nothing to Disclose

00030490-DMT et al, Abstract Co-Author: Nothing to Disclose

A novel clinical system for digital mammography based on a direct conversion detector and an optical readout has recently been introduced in the market. This unit, named AMULET and manufactured by FUJIFILM, is based on a dual layer of amorphous Selenium which acts both as converter of X-rays (first layer) and optical switch for the readout of signals (second layer), by means of line light source. The optical readout is supposed to improve the noise characteristics of the detector. In fact, the combination of the optical switching technology and the direct conversion with amorphous Selenium should be able to provide high resolution images with low noise. Here, we are presenting a characterization of an AMULET system, in terms of physical figures (MTF, NNPS, DQE) and contrast-detail analysis.

The physical and psychophysical characterization of the clinical unit was obtained at different exposures for two beams: 28 kV Mo/Mo (namely RQA-M2) and 28 kV W/Rh (namely W/Rh). The presampling MTF was measured by using the edge technique. We also achieved the contrast-detail investigation by using the CDMAM 3.4 phantom.

The system presents MTF values slightly worse than other flat panels based on direct-conversion and comparable with indirect flat panels: the MTF of the AMULET system is about 45% at 5 lp/mm. AMULET demonstrates NNPS results considerably better (up to 2-3 times lower) than those obtained with direct-conversion flat panels and also better than flat panels based on scintillation phosphors. The good spatial resolution and the excellent noise properties allow the achievement of DQE of about 70% and nearly 80% for the RQA-M2 and W/Rh beams, respectively. Also the contrast detail analysis accomplished with human observers shows a better behavior of the AMULET system, with respect to published values for many other systems for full-field digital mammography.

The novel clinical system presented very interesting results, both in terms of physical characterization, and in contrast-detail analysis. In particular, the direct-conversion provides good MTF, and the novel system presented excellent noise characteristics, thanks to the optical reading . This combination allows achieving a DQE better to those published for clinical FFDM systems. The psychophysical analysis basically confirmed the excellent behavior of the AMULET unit.

 

Lanconelli, N, Rivetti, S, Bertolini, M, Borasi, G, Golinelli, P, Nitrosi, A, Gallo, E, Donini, B, Costi, T, Nocetti, L, et al, 0, Characterization of a Novel Clinical Unit for Full-field Digital Mammography Based on Amorphous Selenium and Optical Switching.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8002362.html