Clinical mammography at the SYRMEP beam line: Toward the digital detection system

From the very beginning, the Synchrotron Radiation (SR) for Medical Physics (SYRMEP) collaboration has studied possibilities of improving image quality in mammography, by optimizing source and detector devices. Preliminary studies on test objects and 'in vitro' breast tissue samples have been carried out at a dedicated bending magnet beam line built at the ELETTRA SR facility. Exploiting the characteristics of SR beams, it has been possible to investigate several phase-sensitive imaging techniques. After the approval of the concerned authorities, clinical examinations have been started with encouraging results. In a first step, screen film systems are used as detection device, but the use of digital detectors is presently under investigation. As custom solution, silicon microstrip sensors of 50 μm pitch, designed by INFN Trieste and manufactured by Hamamatsu, have been directly bonded to the Mythen single-photon counting read out electronics developed at the Swiss Light Source for SR diffraction experiments. The new version of the read-out ASIC has been tested at the SYRMEP beam line and proved to be able to operate with low noise and high counting rates also for imaging applications, where the cross-talk between the channels is extremely critical