Currently, there are about 60 to 70 000 individuals on the surveillance program per year out of >500 000 registered asbestos exposed persons, 240 000 of them get an offer for medical examination, lung function and a chest X-ray every 3 years. Ca. 90% of the data (results of examination, lung function and conventional ILO-coding sheet) are transferred online.
Approximately 10% of the examined candidates gets a Low Dose Volume-HRCT. Lung cancer screening examinations in a high risk group have been started. Depending on the knowledge using the ILO International Classification of Radiographs of Pneumoconioses as universal standard for screening and health surveillance of individuals occupationally exposed to dusts, a standardised coding system has been demanded as obligatory not only for epidemiological purposes, but also as diagnostic criteria for occupational diseases.
The ILO classification is a standard surveillance tool, in use for more than 50 years in Germany. In 2005, a monograph ‘International Classification of HRCT for Occupational and Environmental Respiratory Diseases – ICOERD’ has been published. The work represented a consensus of international experts from Belgium, Finland, France, Germany, Great Britain, Japan and United States on a principal coding system along with reference films and imaging parameters. The reference films include examples with 5 and 1 mm slice thickness (incremental CT) for typical pleural and parenchymal findings.
Experienced radiologists will make the classification, or a CD-ROM with subjects’ images will be sent to a B-Reader for classification. For coding purposes the reference-films are part of the classification. The reading results will be stored online at the Online-Portal-GVS-Server, which is provided by GVS – Health Prophylaxis – a joint facility of the German Statutory Accident Insurance.
ILO-criteria for diagnosing asbestos related diseases are as follows: s, t, u irregular densities, more or equal 1/1 without and 1/0 with inspiratory crackles or impairment of vital capacity, pleural thickening (plaque also unilateral at least 3 mm thickness, length 2 cm, diffuse pleural thickening 2a both middle and lower field). ICOERD criteria for diagnosing asbestos related diseases are as follows: irregular and/or linear opacities in both lower and/or middle fields, sum profusion of at least 4, any visible pleural thickening, visceral or pleural at least 1a, with or without calcification, after exclusion of other causes. Similar criteria for silicosis will be presented.