<title>Design and performance of a high-quality cardiac flat detector</title>

Abstract

A dynamic flat detector with optimized overall system design has been developed by Trixell together with its partners. This detector enables the application of flat detector technology in cardiac procedures, including difficult applications like low-dose fluoroscopy, and later extending to digital subtraction angiography and high-speed bi-plane. The key parameters for the optimized design are the high DQE over a large dose range, the excellent linearity and the temporal behavior of the detector. High DQE performance could be realized best by using a thick CsI layer for high absorption. This guarantees a salient MTF of 65 percent at 1 lp/mm and 37 percent at 2 lp/mm even for thick layers because the detrimental effects of the dead layer are avoided. The well known temporal artifacts problems associated with a:Si-CsI technology have been solved using flashes of light in combination with a reset sequence at the beginning of every frame, which keeps the traps in the a-Si photodiodes constantly filled. Switching dose levels therefore leads only to a marginal change in the trap occupation, resulting in a low temporal cross-talk. Experimental data for the mentioned applications are demonstrated.