||Improvement of the Modulation Transfer Function of CsI(Tl)-scintillator Mammography Detectors
|| CsI(Tl)-scintillator indirect detector; Detective quantum efficiency; Mammography detector; Modulation transfer function; Radiography detector
||Modulation transfer function (MTF) performance of indirect detectors based on the cesium iodine doping thallium (CsI(Tl)) scintillator is commonly worse than that of a direct detector that is based on the amorphous selenium (a-Se) photoconductor because of light-photon scattering in the scintillator layer. In this paper, the MTF performance of an indirect mammography detector was improved from an image restoration technique based on the Wiener filter maintaining the performance of the detective quantum efficiency. In order to adaptively conduct Wiener filtering depending on object powers, we adaptively calculate an object variance to obtain a simplified spectrum ratio. Using a columnar CsI(Tl)-scintillator mammography detector, we acquired x-ray breast images and could adaptively improve the MTF performance of x-ray images from the proposed algorithm without calculating complicated power spectral densities.