[First clinical experiences with a new large frame intensifier in thoracic diagnosis].

In 350 patients with 870 pathologic findings comparative blind analysis of conventional chest films and biplane 100 mm photofluorographic images taken with the large-field image intensifier revealed high accuracy in the evaluation of coin lesions, hilar and pleural pathology, pulmonary vasculature and the right paratracheal stripe. Moderate central interstitial edema, more subtle interstitial changes particularly in the lung periphery including Kerley's B-lines, and calcifications in the hilum or the aortic arch are not visible in all cases for the evaluation of lesions of the ribs special films continue to be mandatory. Lateral views are of good quality. The spatial resolution of the large-field image intensifier was measured to be 4.5-5.2 LP/mm at the output phosphor, the spatial resolution of the 100 mm intensified images ranges from 2.6-3.8 LP/mm in the center. Mean skin dose was found to be 6.3 mrd in the p.a. projection which is less than 5% of the values registered in non-intensified photofluorography and even by factor 5 lower than in conventional chest x-ray using rare earth screens.