99Tcm tetrofosmin uptake in mediastinal tumours.

We present our experience in visualizing mediastinal tumours using 99Tcm tetrofosmin. Three patients with thymic tumours and two patients with a mediastinal tumour (seminoma and small cell carcinoma) were found to have anterior mediastinal masses on chest radiographs, and subsequently underwent computed tomography and magnetic resonance imaging. In addition, the patients underwent single photon emission computed tomography (SPECT) with 99Tcm tetrofosmin and 201Tl. Intense uptake was seen on early 99Tcm tetrofosmin images in three patients with thymoma, invasive thymoma and mediastinal tumour (small cell carcinoma). In the remaining two patients with thymic carcinoma and mediastinal seminoma, there was intense 99Tcm tetrofosmin uptake on early images which reduced on delayed images. 201Tl uptake was intense on both early and delayed images. These findings suggest that different 99Tcm tetrofosmin uptake in early and delayed imaging may offer new information on these mediastinal tumours.