[Radiographic and xeroradiographic case finding in asbestosis]

Statistical researches were carried out on subject samples exposed to asbestosis risk with the aim of investigating the advantages of xeroradiographic methods when applied to the early diagnosis of this occupational disease. In the initial phase of the research, the aim was to quantify the statistical incidence of minimum asbestosis. Thus the frequency of initial forms was compared with developed forms in 750 subjects working with amianthus cement. These subjects had been homogeneously exposed to asbestosis risk (as research on the environment in the factory confirmed), and over a period of 10 years had been checked radiographically at the Clinica del Lavoro of the University of Pavia. This first phase of the research confirmed the remarkable incidence of the disease. In the subsequent phase, the radiographs of 200 subjects with asbestosis were studied. The aim was to quantify the frequency of the different radiological symptoms of the disease. In the final phase of the research, both traditional radiographs and xeroradiographs were obtained on 51 subjects exposed to asbestosis risk with pulmonary alterations, although with no (or not significant) radiographic techniques in the early diagnosis of asbestosis would thus become clear. For protective reasons, the use of xeroradiography is proposed not for mass screening but only for controlled investigations. Xeroradiography can evidence plaques or pleural fibrous alterations, which would not be shown on traditional radiographs. It also allows more satisfactory examination of the small fibrous parenchymal opacities at the base of the lungs. On the other hand, additional controlled examinations of the same subjects, even when use was made of projections for pleural backgrounds and lordotic projections for the parietal pleurae, reduced earlier favorable statistics by half. However, the wide range of xeroradiography can evidence nearly all radiographic symptoms in a single xeroradiograph. This greatly facilitates routine examination while providing more satisfactory iconographic data for subsequent medico-legal discussion.