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A Comparison of the Profusion and Type of Small Opacities Reported with the 1980 and 1971 ILO Classifications using Readings from the Coalworkers' X-ray Surveillance Program.

Attfield-MD; Hodous-T; Althouse-R
NIOSH 1990 Sep:207-212
A comparison study of the profusion and type of small radiographic opacities reported using the 1980 and 1971 International Labour Office (ILO) classification systems was performed. A total of 7338 chest X-ray films obtained from the Coalworkers' X-ray Surveillance Program (CWXSP) were analyzed in 1981 by B-readers using the 1971 ILO system for classifying radiographic opacities. A total of 7438 films were analyzed using the 1980 ILO system after the CWSXP switched from the 1971 to the 1980 system. The overall percentage of films showing small opacities was the same for both systems, 6.1%. The percentage of opacities read as being category 0/1 or greater was 56% when the 1971 system was used and 52% when the 1980 system was used. The difference was not statistically significant. For rounded opacities, the percentage of opacities reported as being p-type, q-type, or r-type was similar when either system was used. For irregular opacities the percentage of s-type opacities reported using the 1980 system was significantly greater than when the 1971 system was used. The percentage of t-type opacities was proportionately decreased. Most of the increase in s-type opacities occurred in films classified as 1/1 or greater. Films from miners with longer underground exposures were more likely to be classified as having rounded opacities under the 1971 system than under the 1980 system. The number of irregular opacities reported appeared to increase with time, primarily as a result of fewer p-type opacities being reported. The authors conclude that introduction of the 1980 ILO classification system has had little lasting effect on the way small opacities are reported.
NIOSH-Author; Chest-X-rays; X-ray-analysis; Lung-lesions; Coal-workers-pneumoconiosis; Coal-miners; Occupational-exposure; Surveillance-programs;
Publication Date
Document Type
Conference/Symposia Proceedings;
Fiscal Year
NTIS Accession No.
NTIS Price
Identifying No.
DHHS (NIOSH) Publication No. 90-108
Source Name
Proceedings of the VIIth International Pneumoconioses Conference