High-performance Dual-energy Imaging with a Flat-panel Detector

Mounting evidence suggests that the superposition of anatomical clutter in x-ray chest radiography poses a major impediment to the detectability of subtle lung nodules. Through decomposition of projections acquired using different x-ray energy spectra, dual-energy (DE) imaging offers to dramatically improve lung nodule conspicuity. The development of a high-performance DE chest imaging system is reported, with design and implementation guided by fundamental imaging performance metrics. Analytical and experimental studies of imaging performance guided the optimization of key acquisition technique parameters, including x-ray filtration, allocation of dose between low- and high-energy projections, and peak-kilovoltage selection. To minimize anatomical misregistration between images, a cardiac gating system was designed and implemented to direct x-ray exposures to within the quiescent period of the heart cycle. The instrumentation and optimal imaging techniques have been incorporated in a DE imaging prototype system now deployed in a clinical study to evaluate the diagnostic performance of DE imaging.MAS