[The importance of thoracic radiology for public health since 1896].

Without imaging procedures a variety of chest diseases cannot be diagnosed sufficiently. Examples are acute and chronic pneumonia, toxic effects on the bronchial and alveolar system, immunologic and malignant changes and cardiovascular disease involving the lung. Especially important are the types of disease that attack large sections of a population, because a path of infection may be hidden or because of short- or long-term exposure to relevant concentrations of toxic or allergic agents--not necessarily recognized as such--at work, in the general environment or associated with certain types of behaviour or illness. All this may have effects on biostatistical and socioeconomic data. Considering available epidemiologic data on morbidity and mortality, then pulmonary tuberculosis, unspecific pneumonias, drug-induced and AIDS-associated lung disease, pneumoconioses (silicosis and asbestosis) and primary and secondary chest malignancies have to be included in this category. Conventional chest radiography with high-kV technique and modern film-screen combinations continues to be the imaging modality for initial evaluation of chest disease worldwide. Low radiation exposure, low cost and overall availability are major advantages. Conventional tomography, however, has nowadays been largely replaced by CT, though a few special indications remain. High-resolution CT (HRCT) and the spiral technique bring additional benefits. Periodic radiographic mass screening of populations with certain disease prevalence still seems feasible, taking risk assessment, cost effectiveness and radiation exposure into account.(ABSTRACT TRUNCATED AT 250 WORDS)