We are implementing an X-ray breast Computed Tomography (CT) system on the gantry of a dedicated single photon emission tomography system for breast Tc-99 imaging. For the breast CT system we investigated the relevance of the beam hardening artifact. We studied the use of a single photon counting silicon pixel detector (0.3mm thick, 256 x 256 pixel, 55 mu m pitch, bump-bonded to the Medipix2 photon counting readout chip) as detector unit in our X-ray CT system. We evaluated the beam hardening "cupping" artifact using homogeneous PMMA slabs and phantoms up to 14cm in diameter, used as uncompressed breast tissue phantoms, imaged with a tungsten anode tube at 80 kVp with 4.2 mm Al filtration. For beam hardening evaluation we used a bimodal energy model. The CT data show a "cupping" artifact going from 4% (4-cm thick material) to 18% (14-cm thick material). This huge artifacts is influenced by the low detection efficiency and the charge sharing effect of the silicon pixel detector. (C) 2007 Published by Elsevier B.V.
|Autori:||Bisogni M; Del Guerra A; Lanconelli N; Lauria A; Mettivier G; Montesi MC; Panetta D; Pani R; Quattrocchi MG; Randaccio P; Rosso V; Russo P|
|Titolo:||Experimental study of beam hardening artifacts in photon counting breast computed tomography RID F-8402-2011|
|Anno del prodotto:||2007|
|Digital Object Identifier (DOI):||10.1016/j.nima.2007.07.036|
|Appare nelle tipologie:||1.1 Articolo in rivista|