The Threshold Visibility of Pulmonary Shadows

摘要: What should a radiologist be expected to see on chest film? is the size, shape, and contrast of least perceptible shadow? Yerushalmy (1950) found that 32 per cent suspicion-worthy pulmonary shadows are missed by “competent” film readers. Birkelo (1947) has shown 35-mm. photofluorograms as efficient at detecting lesions full-sized double-screen technic. A tumor 6 mm. in diameter may close invisible. How then can vessels from 1 3 produce obvious lacework fields? lung full tubercles 1.5 present an appearance quite easy diagnose, yet single 1.5-mm. shadow below threshold. number researches fundamentals roentgen visibility have been published. Burger (1949) showed mutual dependence size needed make visible, pointed out inferiority fluoroscopy photofluorography, but he worked with sizes much smaller than most pulmonary...