An X-ray imaging apparatus is disclosed. The apparatus includes a radiator housing, an X-ray tube, a source of X-rays and at least one filtration material disposed on the X-ray tube. The X-ray tube is rotatable about a longitudinal axis and is disposed at least partially within the radiator housing. The source of X-rays emits at least one X-ray beam at least partially through the X-ray tube. The X-ray beam exits the X-ray tube at an annular X-ray window. The filtration material at least partially covers a portion of the annular X-ray window. Rotation of the X-ray tube causes the X-ray beam to pass through a plurality of locations in the annular X-ray window and at least a portion of the X-ray beam is filtered by the filtration material.