201Tl scintigraphy in the staging of lung cancer, breast cancer and lymphoma.

To evaluate 201Tl in the detection of the primary tumour, lymph node involvement and mediastinal spread we have studied a total of 188 patients with histologically proven lung cancer, breast cancer or malignant lymphoma. Ten patients with benign lung disease were also examined. Static images were performed 20 min after intravenous injection of 75 MBq of thallous (201Tl) chloride. The results were compared with those of standard staging procedures including CT scanning and mediastinal exploration. Thallium-201 imaging was highly sensitive in detecting the primary tumour (lung cancer 86%, breast carcinoma 100%, lymphoma 85%), but showed low sensitivity in detecting mediastinal spread or lymph node involvement. Thallium-201 uptake was also observed in active sarcoidosis (one case) and active TB (two cases). We conclude that 201Tl imaging is unlikely to have a clinically useful role in the diagnosis or staging of lung cancer, breast cancer or lymphoma.