Technetium-99M-Tetrofosmin Uptake in Malignant Lung-Tumors

Abstract

Technetium-99m-tetrofosmin is a new myocardial imaging agent which has yielded promising results compared to thallium-201. The tumour-seeking properties of the routinely used cardiac radiopharmaceuticals (TI)-T-201 and Tc-99m-methoxyisobutylisonitrile are well known. Here we report the results of a pilot study demonstrating Tc-99m-tetrofosmin uptake in malignant lung tumours. Five patients with bronchial carcinoma, each in different stages of chemo- or radiotherapy, were imaged, Dynamic and static acquisitions were performed to evaluate the uptake and kinetics of Tc-99m-tetrofosmin in the lesions, In four of the five patients localized tumour uptake of Tc-99m-tetrofosmin was observed. Time to peak tumour activity and tracer washout in the tumour, myocardium and contralateral normal lung at 30 min post injection (p.i.) were determined. Tumour/normal lung, heart/tumour and heart/contralateral normal lung ratios were calculated for 5-10, 25-30 and 85-90 min p.i. The peak concentration in all tumours was reached at the end of the first minute, The mean tumour and contralateral normal lung washout rates of Tc-99m-tetrofosmin at 30 min p.i. were 18.3%+/-9.2% and 19.5%+/-5.85% respectively, The tumour/contralateral normal lung ratio remained higher than 1.25 until 90 min p.i. in all four patients. It is concluded that Tc-99m-tetrofosmin seems to be of value in lung tumour imaging, although larger studies are necessary to ascertain its sensitivity, specificity and usefulness in clinical practice.