1. A computed tomography (CT) apparatus, comprising: processing circuitry configured to obtain projection data representing an irradiance of radiation detected at a plurality of detectors and corresponding to a plurality of projection angles of a radiation source; obtain a gate signal; select a subset of the projection data to be gated projection data corresponding to gated projection angles indicated by the gate signal; determine weighting-and-feathering coefficients according to the gated projections angles; reconstruct a tomographic image from the gated projection data using an iterative reconstruction method including a regularization term and using the weighting-and-feathering coefficients.