<title>An evaluation of sharpness in different image displays used for medical imaging</title>

X-ray film systems have been widely used for a diagnosis of various diseases since a long time ago. In recent years, many kinds of displays and recording systems for X-ray medical images have been used including inkjet printer, silver halide film, CRT and LCD, by the development of the digital X-ray image capturing systems. In this paper, image quality of X-ray images displayed onto high accurate monochrome CRT and LCD monitors are analyzed and compared. Images recorded on the exclusive film and coated paper by inkjet printer and the wet type and dry type photo printers using a silver halide material are also analyzed and compared. The modified Gan's method is introduced to calculate the MTF (Modulation Transfer Function) from the knife ESF (edge spread function). The results show that the MTFs of the inkjet image on the transparency and the wet type silver halide film image have fairly similar and good response in comparison with the inkjet image on the coated paper and the dry type silver halide film. It is also shown that the CRT has the worse response over the spatial frequency range. It was well correlated between the MTF and observer rating value. From here, we consider the proposed method is effective.