Patent ID: 8724889

Claim:
A method for CT image reconstruction, comprising: selecting projection data of a same height on a curve whose curvature is approximate to that of a scanning circular orbit; implementing, by a computer processor, weighting processing on the selected projection data; filtering, by the processor, the weighting processed projection data along a horizontal direction; and implementing, by the processor, three-dimensional back projection on the filtered projection data along a direction of a ray; wherein: the selecting of the projection data includes selecting projection data according to the formula P C - FDK ⁡ ( θ , t , c ) = P ⁡ ( θ - arcsin ⁢ t R , tR R 2 - t 2 , c · R 2 2 ⁢ ( R 2 - t 2 ) - R ⁢ R 2 - t 2 ) ; P C-FDK (θt,c) indicates the selected projection data; θ indicates a projection direction; t indicates a distance between parallel fan beams; c indicates an angular sampling interval in a Z axis direction; and R indicates a radius of the circular orbit.