Flat-panel-detector-based cone beam volume CT imaging: detector evaluation

Recent development of large area flat panel solid state detector arrays indicates that flat panel image sensors have some common potential advantages: compactness, absence of geometric distortion and veiling glare with the benefits of high resolution, high DQE, high frame rate and high dynamic range, small image lag (less than 1%) and excellent linearity (approximately 1%). The advantages of the new flat-panel detector make it a promising candidate for cone beam volume CT imaging. The purpose of this study is to characterize an amorphous silicon thin film transistor (STFT) flat panel detector-based imaging system for cone beam volume CT applications. A prototype STFT detector-based cone beam volume CT imaging system has been designed and constructed based on the modification of a GE 8800 CT scanner. This system is evaluated using two phantoms: a low contrast phantom, and a GE CT quality assurance phantom. The results indicate that the flat panel detector-based volume cone beam can achieve a better spatial resolution than that of a standard fan beam CT and a low contrast resolution approaching that of a standard fan beam CT. The results also suggest that to use a flat panel detector for cone beam Volume CT, the design and construction of the detector should be optimized for tomographic acquisition and reconstruction.