Abstract
This paper discribes a comparative study of measurement methods of modulation transfer functions ( MTF ) of X-ray CT-images. They are 1) a contrast method which uses the response to a square wave chart of Lucite in water phantom,2) an edge method which uses the response to an interface of Lucite and water, and 3) a wire method which uses the response to a thin metal wire inserted perpendicularly to a tomographic slice. An experiment with Pfizer AS&E CT model-0450 showed that three methods gave practically the same MTFs for the same scan conditions. But because the contrast method ( method 1) ) showed the smallest measurement error and did not need the additional software which was necessary for the other methods, it was the most practical for measuring MTF of X-ray CT-images.
