Gallium-67 scintigraphy in lung diseases.

There is some disagreement in the literature about the tumour affinity and tumour specificity of gallium-67 (6VGa). The present investigation showed good uptake of 67Ga in most cases of bronchial carcinoma, but some uptake of 67Ga was also found in 30% of those with non-malignant lung lesions. There was no relationship between the uptake of 17Ga and the histo-logical type of bronchial carcinoma. After radiotherapy, a transient uptake of 67Ga in the irradiated field was seen. In five patients who were studied again two months after the end of radiation treatment, uptake of 67Ga was no longer demonstrable at the original site of the tumour. 67Ga appears to be an isotope with a high affinity for bronchial carcinoma but it is not tumour specific. However, our experience indicates that a negative 67Ga scintigram of the lung in a case of suspected malignancy calls for reconsideration of the clinical diagnosis. Edwards and Hayes (1971) reported that gallium-67 (67Ga) was taken up by bronchial carcinoma but that this uptake was much more striking in cases of squamous-cell carcinoma than in other histological types. We have studied the tumour specificity of 7Ga citrate in lung lesions, the influence of radiotherapy, and the uptake of 17Ga in relation to the histological type of carcinoma. METHODS Our scans were taken two to three days after the intravenous administration of 2 mCi "Ga (as carrier-free gallium citrate) when normally a high activity was found over the liver. We used a Picker Magna-scanner V with a spectrometer window setting of 160 to 320 KeV and an 85-hole collimator. The maximum count rate was 4,000-6,000 counts/min, the ratemeter range 6 K, the count range differential 40%, and the scanning speed about 40 cm/min. We graded the uptake in the lung lesions by comparing the 67Ga count rate over the lesion with that over the liver and with the corresponding area of supposedly normal contralateral lung. We graded ++ when the count rate over the lung lesion was as high as or higher than that over the liver (Figs. 1 and 2), + when the count rate over the lesion was lower than that over the liver, and-when there was no uptake seen in the lesion. MATERIAL 67Ga scintigraphy was performed in 79 patients with lung diseases. In 53 cases the clinical diagnosis was bronchial carcinoma, confirmed by either histological or cytological methods in 41 cases (Table I). RESULTS …