Standard chest ILO radiograph of small "t" irregular opacities

This is a standard International Labour Organization (ILO) radiograph demonstrating small irregular opacities of the profusion and type, "3/3 t/t", typical for asbestosis. The degree of profusion of the irregular opacities in this radiograph is designated "3/3", using the ILO scale for the concentration of opacities that ranges from "0", meaning no opacities, to "3", meaning profuse. The "t" designation refers to irregular opacities with a width of 1.6 to 3 mm. The ILO description of "t/t" means that all or virtually all of the opacities are size "t". In contrast, if most of the opacities were "t", but some were "s", then the designation "t/s" would be used.