A detector response adaptive helical reconstruction algorithm

With the recent introduction of multi-slice CT (MCT) by many CT manufactures, research on the subject of multi-slice helical reconstruction has gained significant interests. These algorithms take advantage of the available conjugate samples in the multi-slice configuration and estimate a set of projections at the predefined plane-of-reconstruction (POR). In many clinical applications, sub-mm slice thickness is desirable. Unlike the case of a single-slice scanner, the slice thickness of a MCT is determined by the detector cell pitch. For a detector design that a minimum cell pitch of 1 mm, sub-mm slice thickness is very difficult to achieve. Here, the authors propose a thin-twin scheme in which the X-ray flux is collimated to illuminate only a portion of the center two detector rows. Because the slice thickness in this scheme is determined by the pre-patient collimator, sub-mm slice thickness is obtained. Observing the fact that the X-ray flux profile on the detectors is unsymmetrical, the authors propose a helical reconstruction algorithm that is adaptive to the detector response. Phantom experiments have been conducted to evaluate the performance of the authors reconstruction algorithm.