Gallium-67 scanning for carcinoma of the lung

Gallium-67 citrate scanning was prospectively evaluated in 55 patients who had lung lesions suspected to be primary carcinoma on chest x-ray films and in whom subsequent histologic diagnosis was obtained. Of 47 patients with histologically proved carcinoma of the lung, 44 (94 per cent) had a positive 67Ga scan. No patient with a positive scan had a benign lesion, so that the positive scan accuracy rate was 100 per cent. All 8 patients with a benign lesion and 3 patients with a malignant lesion had negative scans, for a negative scan accurary rate of 72 per cent for benign lesions. These results give statistical validity for the usefulness of the 67Ga scan in diagnosing carcinoma of the lung (p less than 0.001). Tumor cell type had little effect on the sensitivity of 67Ga scan. The 67Ga scan was equally useful in the evaluation of peripheral and central lesions. There was little difference amount T1, T2, and T3 classified lesions in their ability to take up 67Ga. The 67Ga scan was competitive with mediastinoscopy in assessing mediastinal lymph node metastases and provides a noninvasive method of assessing hilar lymph node metastases. There was a good correlation between the clinical staging of patients with lung cancer based on a chest x-ray film and 67Ga scanning and the staging after surgical treatment based on the histology of the resected specimens.