1. An imaging system, comprising: at least one radiation source configured to move along at least one closed path; at least one x-ray radiation detector configured to receive x-ray radiation from the at least one radiation source as the at least one radiation source move along the at least one closed path to allow for generating reconstruction image data of at least a portion of a three-dimensional object; and a gantry configured to enclose the at least one radiation source within an enclosed portion of the gantry, wherein the gantry is configured so as to avoid having any exposed moving parts during an imaging process using the imaging system, and wherein the gantry is configured to enclose the at least one radiation source without fully enclosing the three-dimensional object so as to allow access to the three-dimensional object during the imaging process, wherein the at least one radiation source and the at least one x-ray radiation detector are positioned in the imaging system such that at least a portion of a three-dimensional object can be positioned in between the at least one radiation source and the at least one x-ray radiation detector to facilitate generating the reconstruction image data, wherein the at least one x-ray radiation detector is spaced apart from the at least one closed path, wherein the reconstruction image data comprises three-dimensional reconstruction image data, wherein the at least one radiation source are configured to move continuously while emitting x-ray radiation, and wherein the at least one radiation source is configured to move along the at least one closed path with respect to the at least one x-ray radiation detector, a processor configured to receive projection image data from the at least one x-ray radiation detector and apply a reconstruction algorithm to generate a reconstructed 3D image of the three-dimensional object, wherein the imaging system is configured to provide real-time or near real-time imaging by evolving a reference image of at least a portion of the three-dimensional object to form a sequence of 3D volumes as a function of time, where the reference image is a preceding reconstructed 3D image which is updated at least once over time, to generate the three-dimensional reconstruction image data; and an interface to provide the three-dimensional reconstruction image data to a user.