Gallium-67 as a diagnostic tool in the evaluation of peripheral pulmonary lesions.

, , 355-358. While Gallium-67 shows a high affinity for primary pulmonary tumours, benign pulmonary lesions also concentrate the isotope. In 50 consecutive patients in whom the diagnosis of pulmonary carcinoma was not achieved by other means, the exhibition of Ga showed a positive scan in 36, of whom three, on histological evidence, certainly did not have a pulmonary carcinoma, and in three others radiographic diminution in the extent of the peripheral pulmonary lesion makes most unlikely the diagnosis of carcinoma. In seven of 14 patients in whom the scan was negative it was judged necessary to undertake surgical management. Scanning with Ga may modify the extent of surgical resection in some with a negative scan but does not establish the diagnosis of carcinoma in those with a positive scan, is unsafe as a screening test on which to base the decision on the need for referral to a thoracic surgeon, and in particular does not distinguish between the three common causes of `chronic lung abscess'—chronic destructive pneumonia, cavitated carcinoma, and tuberculosis with cavitation and without tubercle bacilli in the sputum.