Table 3.

Classification of pneumoconiosis chest radiograph: Japanese vs. ILO/ICRP

Japanese classification of pneumoconiosis chest radiograph				ILO/ICRP
Radiographic appearances of pneumoconiosis		Category
ILO/ICRP=The ILO International Classification of Radiographs of Pneumoconioses developed by International Labour Organization Note: In Japan, chest radiographs of pneumoconiosis are recorded and reported as PR categories. The ILO/ICRP system classifies small rounded opacities as 'p', 'q', or 'r', and irregular opacities as 's', 't', or 'u' with increasing size of small opacities. Japanese system classifies small rounded opacities as 'p', 'q', or 'r'; however it has no specification for irregular opacities. Where the size of 'p' or 's' is up to 1.5 mm, 'q' or 't' is 1.5 mm - 3 mm, and 'r' or 'u' is 3 mm -10 mm. This table presented only the classification of small and large opacities.
No radiographic abnormalities due to pneumoconiosis in both lung fields		PR0 (0/–, 0/0, 0/1)		Category 0 (0/–, 0/0, 0/1)
Small opacities profusion in 12-points scale	Small number of rounded or irregular opacities in both lung fields and no large opacities	PR1 (1/0, 1/1, 1/2)		Category 1 (1/0, 1/1, 1/2)
	Large number of rounded or irregular opacities in both lung fields and no large opacities	PR2 (2/1, 2/2, 2/3)		Category 2 (2/1, 2/2, 2/3)
	Very large number of rounded or irregular opacities in both lung fields and no large opacities	PR3 (3/2, 3/3, 3/+)		Category 3 (3/2, 3/3, 3/+)
Large opacities	Largest diameter of 1-5 cm	PR4	A	A
	5cm<Largest diameter<1/3 of one side of lung field (upper 1/3 of right lung field)		B	B
	Size of large opacity or opacities greater than 1/3 of one side of lung field (upper 1/3 of right lung field)		C	C