The cone beam scanning configuration is widely used in many imaging techniques due to its technically simple configuration to implement. Recently, grating based imaging modality has been extended for the cone geometry. One challenge in this field is demonstrating the discrete representation of the physical model which is crucial for implementing iterative reconstruction schemes for the sample discovering. The aim of this project is using the B-spline functions to discretize the forward model and designing iterative methods for image reconstruction. The potential impact of such work could be quite significant; in case of success, it would be immediately incorporated in the data processing pipeline of the TOMCAT beamline at the Swiss Light Source (Paul Scherrer Institute).