Technetium-99m-glucoheptonate lung imaging; has it a role in the diagnosis of bronchial carcinoma?

It has been shown by Vorne et al. and Passamonte et al. that technetium-99m-glucoheptonate (Tc-GH) concentrates in bronchial carcinomas. The two studies reported similar sensitivities (88 and 91%, respectively) but discordant specificities (88 and 10%, respectively). In order to assess the uptake of Tc-GH in bronchial carcinomas we performed lung imaging on patients with an abnormal chest radiograph who were undergoing routine investigations for bronchial carcinoma. 108 patients (85 carcinoma, 23 non-carcinoma) were given 555 MBq (15 mCi) Tc-GH intravenously and scanned 5 h later. Images were assessed by one investigator (J.A.L.) without knowledge of the patient's clinical details or other results. Localized uptake of Tc-GH was seen in 71 out of 85 patients who proved to have bronchial carcinoma. Uptake was also seen in 16 out of 23 patients with a variety of non-malignant lung conditions. Sensitivity for bronchial carcinoma was 84%, and specificity 30%. Uptake did not vary significantly with histology. Eleven out of 12 patients with proven tuberculosis had increased uptake of Tc-GH; two of those patients also had inactive lesions which did not concentrate the tracer. In conclusion, Tc-GH is of limited value in the diagnosis of bronchial carcinoma, because of its low specificity. A possible role in the diagnosis of active tuberculosis may exist, following further assessment.