Pulmonary Uptake of Gallium-67 in Asbestos-exposed Humans and Sheep1,2

Abstract

To evaluate the ⁶⁷Ga lung uptake as an indicator of inflammatory activity in asbestosis, we obtained ⁶⁷Ga lung scans in 58 long-term asbestos workers. The ⁶⁷Ga localized excessively in the lungs of 17 of the 21 workers with asbestosis. Among workers without sufficient criteria for the diagnosis of asbestosis, the ⁶⁷Ga scan index was significantly increased in 43% (16 of 37). Among the 16 with positive ⁶⁷Ga scan, abnormal pressure-volume curve and/or gas ex-change data were found in 87%, whereas in the 21 workers with negative ⁶⁷Ga scan, similar abnormalities were found in only 29%. In the sheep model of the disease, bronchoalveolar analysis after ⁶⁷Ga scan demonstrated that the excessive uptake of ⁶⁷Ga in asbestosis is caused by enhanced serum protein leakage and macrophage accumulation in the lung. Thus, ⁶⁷Ga scanning in asbestos workers may be a useful indicator of early lung damage.