Standard ILO chest radiograph of small "r" nodular opacities

This is a standard International Labour Organization (ILO) radiograph demonstrating a profusion of small, rounded opacities designated "r" for >3 to 10 mm. The ILO description of this radiograph is "r/r" meaning that all or virtually all of the opacities are size "r". However, if the opacities were of different sizes (eg, r and q), the first letter would reflect the most frequent size and the second letter the less frequent size. Thus, if most of the opacities are "r", but some are "q", the designation "r/q" would be used. The degree of profusion of the small opacities in this radiograph is designated "3/3", as the profusion is exactly consistent with a standard "3". The ILO scale for the concentration of opacities ranges from "0", meaning no opacities, to "3", meaning profuse. If the reader thought the profusion was between "3" and "2", but closest to "3", the designation "3/2" would be used for profusion.