Technetium-99m tetrofosmin single photon emission computed tomography in the evaluation of suspected lung cancer

Technetium-99m-tetrofosmin is a radiopharmaceutical employed for myocardial imaging, which has recently emerged as useful in the visualization of tumo urs. In this study technetium-99m-tetrofosmin was evaluated for its accurac y in differentiating malignant from benign pulmonary lesions, and in detect ing mediastinal node metastasis due to lung cancer. Eighty-one patients wit h a solitary lung lesion on the chest radiograph and/or CT scan were submit ted to chest single photon emission computed tomography after technetium-99 m-tetrofosmin injection (740 MBq i.v). The scintigraphic findings were corr elated to the final histopathological diagnosis, demonstrating abnormal tra cer accumulation in 51 of 54 malignant lesions (sensitivity 94% and in 4 ou t of 27 benign conditions (specificity 85%, yielding an accuracy of 91 % Me diastinal lymph-node involvement was evaluated in 35 patients with non smal l cell lung cancer who underwent mediastinoscopy and/or surgery. Tetrofosmi n accuracy (89% was significantly higher than that of CT (69%, p < 0.05); t he false negative scintigraphic results were in nodes sized less than 1 cm. In conclusion technetium-99m-tetrofosmin imaging is useful in distinguishi ng malignant om benign pulmonary lesions, and in non-invasively assessing m ediastinal node metastases from non small cell lung cancer, especially in p atients with enlarged nodes by CT scan.