Experimental evaluation of a simple algorithm to enhance the spatial resolution in scanned radiographic systems

In order to ensure an early diagnosis of breast cancer, an imaging system m ust fulfil extremely stringent requirements in terms of dynamic range, cont rast resolution and spatial resolution. Furthermore, in order to reduce the dose delivered to the patient, a high efficiency of the detector device sh ould be provided. In this paper the SYRMEP/FRONTRAD (SYnchrotron Radiation for MEdical Physics/FRONTier RADiology) mammography project, based on synch roton radiation and a novel solid state pixel detector, is briefly describe d. Particular relevance is given to the fact that the radiographic image is obtained by means of a scanning technique, which allows the possibility of utilizing a scanning step smaller than the pixel size. With this procedure , a convolution between the real image and the detector point spread functi on (PSF) is actually acquired: by carefully measuring the detector PSF, it is possible to apply a post-processing procedure (filtered deconvolution), which reconstructs images with enhanced spatial resolution. The image acqui sition modality and the deconvolution algorithm are herein described, and s ome test object images, with spatial resolution enhanced by means of the fi ltered deconvolution procedure, are presented. As discussed in detail in th is paper, this procedure allows us to obtain a spatial resolution determine d by the scanning step, rather than by the pixel size. (C) 2000 American As sociation of Physicists in Medicine. [S0094-2405(00)00811-7].