Edge Phantom Measures Sharpness of X-Ray Detectors

Digital radiography makes use of Xray detectors that yield a radiographic image of the object or patient between the X-ray source and the detector. Tools have been developed to assess the image quality characteristics of radiation images. One tool is an edge phantom, placed between source and detector, to assess the sharpness of the radiation image obtained. The edge-like, spatial step-response of the system resulting from a sudden change in irradiation level, invoked by the phantom, can be used to calculate the modulation transfer function (MTF) in a particular direction. In this way, the sharpness of the detector can be assessed.