Purpose: In past few years,the inverse geometry computed tomography(IGCT)system has been developed to overcome shortcomings of a conventional computed tomography(CT)system such as scatter problem induced from large detector size and cone-beam artifact.In this study,we intend to present a concept of a four-dimensional(4D)IGCT system that has positive aspects above all with temporal resolution for dynamic studies and reduction of motion artifact.Methods: Contrary to conventional CT system,projection data at a certain angle in IGCT was a group of fractionated narrow cone-beam projection data,projection group(PG),acquired from multi-source array which have extremely short time gap of sequential operation between each of sources.At this,for 4D IGCT imaging,time-related data acquisition parameters were determined by combining multi-source scanning time for collecting one PG with conventional 4D CBCT data acquisition sequence.Over a gantry rotation,acquired PGs from multi-source array were tagged time and angle for 4D image reconstruction.Acquired PGs were sorted into 10 phase and image reconstructions were independently performed at each phase.Image reconstruction algorithm based upon filtered-backprojection was used in this study.Results: The 4D IGCT had uniform image without cone-beam artifact on the contrary to 4D CBCT image.In addition,the 4D IGCT images of each phase had no significant artifact induced from motion compared with 3D CT.Conclusions: The 4D IGCT image seems to give relatively accurate dynamic information of patient anatomy based on the results were more endurable than 3D CT about motion artifact.From this,it will be useful for dynamic study and respiratory-correlated radiation therapy.