[Image quality evaluation and dosage requirements of digital image intensifier radiography]

In the course of a study of the advantages and disadvantages of digital image intensifier radiography, image quality and dose requirements were measured, using a phantom. Spatial resolution was related to exposure parameters, the differentiation of structural details at varying contrast concentrations and the phantom entry doses. Spatial resolution was approximately 1.8-2.0 line pairs/mm (lp/mm) and there was no recognisable effect from increasing the dose or the thickness of the phantom. Additional subsequent edge enhancement led to increased detail recognition 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 radiography with image intensifier techniques can therefore be recommended. Optimal spatial and contrast resolution is obtained at 80-90 keV. However, some reduction in perception of the finest structural details must be accepted.