1. A method of tomographical imaging of an object, the method comprising: providing a snapshot image data obtained in an X-ray projection to the object from a first relative location that is at a first distance from a point on the object and at a first orientation to the point on the object, wherein the snapshot image data comprises image information representing an interested portion of the object and at least one outside portion located outside the interested portion; providing a tomographical image data obtained in an X-ray scan comprising a plurality of X-ray projections to the object from locations surrounding the object; simulating an X-ray projection to the object from the first relative location using the tomographical image data, thereby generating a simulated snapshot image data comprising image information which represents another outside portion that is neither the interested portion nor the at least one outside portion; and constructing another tomographical image data of the interested portion using the snapshot image data and the simulated snapshot image data.