IMAGE QUALITY AND DOSE REQUIREMENTS OF DI GITAL IMAGE INTENSIFIER RADIOGRAPHS

In the course of a study of the advantages and disadvantages of digita l image intensifier radiography, image quality and dose requirements w ere measured, using a phantom. Spatial resolution was related to expos ure parameters, the differentiation of structural details at varying c ontrast concentrations and the phantom entry doses. Spatial resolution was approximately 1.8-2.0 line pairs/mm (lp/mm) and there was no reco gnisable effect from increasing the dose or the thickness of the phant om. Additional subsequent edge enhancement led to increased detail rec ognition up to 2.0 lp/mm. Also, phase inversion of the image (negative image) can improve detail recognition. Radiation dose can be reduced to 15 % compared with conventional imaging methods. Digital radiograph y with image intensifier techniques can therefore be recommended. Opti mal spatial and contrast resolution is obtained at 80-90 keV. However, some reduction in perception of the finest structural details must be accepted.