Comparison of Basic Imaging Properties for Digital Radiographic Systems Based on a Direct Conversion Type of Flat Panel Detector

Abstract

The purpose of this study was to evaluate the basic imaging properties of the two latest digital radiographic X-ray systems, namely, the DynaDirect Winscope 6000 (abbr. as System A, Toshiba Medical Systems) and the Sonialvision Safire Multi (abbr. as System B, Shimadzu Corp.). These systems were based on a direct-conversion flat panel detector (FPD) of amorphous selenium. The basic imaging properties of the two systems were evaluated by measuring characteristic curves, presampled modulation transfer functions (MTFs), and noise power spectra (NPS) using DICOM images to which no resampling was performed with a matrix size of 2048x2048. In addition, noise equivalent quanta (NEQ) and detective quantum efficiency (DQE) calculated from the result of the basic imaging properties were evaluated. The characteristic curves of the two systems showed quite high linearity. The MTFs of the two systems indicated high-resolution properties, as is well known to be an advantage of the direct conversion FPD system. However, the NPS of System A showed better performance than System B under the same exposures. Therefore, the DQE of System A was higher than that of System B at all spatial frequencies.

A feasibility study on reduction of the entrance-surface dose to neonates by use of a new digital mobile X-ray system

“…Because around 0.8 mAs is frequently used as a typical X-ray-imaging condition in the NICU[8], we did not evaluate the linearity for far lower current-time product (mAs) and corresponding pixel value. The linearity in the lower exposure dose region has been shown in some previous studies[9,10,11], including previous models in the CXDI flat-panel detector series.…”