1. A method of generating a synthesized digital projection image, the method executed at least in part by a computer, the method comprising: a) acquiring a plurality of x-ray projection images, wherein each of the x-ray projection images has a corresponding acquisition angle; b) reconstructing a first volume image using the plurality of acquired x-ray projection images; c) performing a forward projection using the first reconstructed volume image that generates at least the following: (i) a preceding forward projection image that corresponds to a first acquired x-ray projection image at a first acquisition angle; (ii) a following forward projection image that corresponds to a second acquired x-ray projection image at a second acquisition angle that is adjacent the first acquisition angle; and (iii) an intermediate forward projection image that corresponds to an intermediate angle that lies between the first acquisition angle and second acquisition angle; d) forming the synthesized projection image by a repeated sequence of: (i) identifying a candidate patch of pixels from within the intermediate forward projection image; (ii) identifying a first patch of pixels from the preceding forward projection image that closely matches the candidate patch of pixels and identifying a first acquired patch of pixels from the first acquired x-ray projection image that corresponds to the first patch of pixels from the preceding forward projection image; (iii) identifying a second patch of pixels from the following forward projection image that closely matches the candidate patch of pixels and identifying a second acquired patch of pixels from the second acquired x-ray projection image that corresponds to the second patch of pixels from the following forward projection image; and (iv) combining the first acquired patch of pixels identified from step d)(ii) and the second acquired patch of pixels identified from step d)(iii) to form a replacement patch of pixels and replacing the candidate patch of pixels from within the intermediate forward projection image with the replacement patch of pixels; e) repeating step c) to generate a first set of a plurality of intermediate forward projection images, wherein each member of the first set is at an angle between two adjacent acquisition angles of the plurality of acquired x-ray projection images; f) repeating step d) to generate each member of a second set of a plurality of synthesized projection images from the first set of intermediate forward projection images; g) reconstructing a second volume image using the plurality of acquired x-ray projection images and the second set of synthesized projection images; and h) generating and displaying a rendered 2-D image from the reconstructed second volume image.