A detector response adaptive helical reconstruction algorithm

With the recent introduction of multislice computed tomography (MCT) by many CT manufacturers, research on the subject of multislice helical reconstruction has gained significant interest. These algorithms take advantage of the available conjugate samples in the multislice configuration and estimate a set of projections at the predefined plane of reconstruction (POR). In many clinical applications, a submillimeter 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 has a minimum cell pitch of 1 mm, submillimeter slice thickness is very difficult to achieve. In this paper, we 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 prepatient collimator, submillimeter slice thickness is obtained. Observing the fact that the X-ray flux profile on the detectors is unsymmetrical, we propose a helical reconstruction algorithm that is adaptive to the detector response. Phantom experiments have been conducted to evaluate the performance of our reconstruction algorithm.