Research Of Reconstruction Algorithm In Helical Cone-beam CT

Since the birth of the first CT (computed tomography) scanner in1972, CT has been widely used in not just Radiological Imaging but Industry. The wide uses of CT also generate great impetus for CT research. Several big changes have taken placed during the past30years. These changes mainly involve in two aspects, one is faster in scanning and reconstruction, the other is better quality of the reconstructed image.This thesis was finished in BMIE’s laboratory of Northeastern University, focus on the simulating helical cone-beam CT projected data and the FDK reconstruction algorithm.The structure of helical cone-beam CT is different from the circle cone-beam CT, it moves in Z axes in every projection, this thesis give the formula of the projection, means can ignore the noise from the machine or electro circuit, fit to evaluate the quality of the reconstructed result. In the process of researching the helical cone-beam reconstruction algorithm, deduce the projection formula of the parallel-scan, fan-scan and helical-scan.The thesis uses the FDK algorithm in helical cone-beam reconstruction, with the detailed deduction for FDK algorithm, the simulation experiment results are showed.In process of the researching the helical cone-beam reconstruction algorithm, the thesis deduct the reconstruction formula of the parallel-beam and fan-beam, the simulation experiment result are also showed. And compared the rebining and half-pixel staggerd algorithm, get the result that combine the rebining and half-pixel staggerd algorithm can restrain the noise.