A beam-filter-based low-dose imaging for multi-detector-row helical CT

Abstract

Low-dose CT has been investigated and employed in various forms for clinical practices. One of the viable options for low-dose imaging is using a multi-slit beam collimator to achieve a sparse sampling. We have earlier demonstrated the feasibility of such technique, and extended the method for dual-energy imaging from a single scan using a multi-slit beam-filter in the circular CBCT system. Multi-detector-row helical CT is indeed in wide use in the clinics. In this work, we continue to explore the beam-filter based imaging technique in the multi-row helical CT scans. We conducted a simulation study by applying a virtual filter to the real data acquired from a helical CT scanner. We separated the sinograms of each row from the multi-row helical CT data, and removed the streaks using a notch filter in the Fourier domain of each sinogram. We then reconstructed the image by use of the filtered-backprojection algorithm and reduced the image noise by applying l0-norm based smoothing.