Role of thallium-201 in the diagnosis of solitary bone lesions.

Thallium-201 is known to accumulate in malignant tumours. In this work we are evaluating the role of thallium in differentiating benign from malignant solitary bone lesions in 28 patients with solitary bone lesions on 99Tcm-MDP bone scans. Lesions' uptake of 201Tl was evaluated using visual assessment and lesion to background ratio. We found significant uptake with a mean lesion to background ratio of 4.27 in malignant lesions and no or faint uptake with a mean lesion to background ratio of 1.37 in benign lesions.

Uptake and kinetics of Tc-99m hexakis 2-methoxy isobutyl isonitrile in benign and malignant lesions in the lungs.

Kinetics of Tc-99m MIBI uptake was studied in 19 patients with lung lesions (6 benign, 13 malignant). Two dynamic studies were acquired after the I.V. injection of 10-15mCi (370-550 MBq); the first was every second for 60 seconds, followed by a second one every minute for 30 minutes. Delayed images were acquired at two and three hours. By assigning regions of interest (ROI) over the lung lesions (TR), contralateral normal lung (NL) and the heart (Ht), time activity curves (TAC) were generated and time to peak activity was calculated as well as the ratios of TR/NL, Ht/TR and Ht/NL. The Ht/NL ratio was also assessed in five patients referred with diagnosis of ischaemic heart disease (IHD) for myocardial imaging. There was a localized increase of Tc-99m MIBI uptake in ten patients with untreated malignant tumours of the lung. No localized uptake was found in one patient with untreated poorly differentiated squamous cell carcinoma, two treated lung cancer and four patients with non-malignant lesions of the lungs. Two patients with fibrosing alveolitis showed diffuse increase lung uptake. In all positive studies peak tumour was reached within the first minute. There was no statistical difference in the ratio of Ht/NL between all groups except in patients with fibrosing alveolitis. There was no significant difference between the ratios TR/NL, Ht/TR and Ht/NL at 5-10 minutes and 25-30 minutes. The ratio of TR/NL at 25-30 minutes was 1.58 +/- 0.36 in the positive cases versus 1 +/- 0.22 in the negative ones.(ABSTRACT TRUNCATED AT 250 WORDS)

Experience with thallium-201 imaging in head and neck cancer.

TI-201 chloride was used for tumor imaging in patients with head and neck cancer. It is of value in detecting the extent of tumor involvement, the presence of residual tumor after radical courses of treatment, and the presence of local recurrence and distant metastases.