1. A system for medical imaging comprising: an acquisition unit comprising a radiation source configured to emit X-rays and an X-ray detector configured to receive X-rays having passed through an object to be imaged and produce numerical values representative of the received X-rays, the acquisition unit movable about the object to be imaged to acquire a plurality of projection images, each at a different angle relative to the object to be imaged; and an image processor that receives an input of a focal point for a synthetic projection image, selects a first projection image and a second projection image adjacent to the focal point from the plurality of projection images, and for each pixel of the synthetic projection image: identifies a first set of object locations in the first projection image and a second set of object locations in the second projection image that contribute to a pixel of the synthetic projection image; and calculates a value for the pixel of the synthetic projection image from pixels of the first set of object locations and the second set of object locations; wherein the image processor creates a synthetic projection image from the calculated values of each pixel of the synthetic projection image.