technetium-tc-99m-depreotide and thallium-chloride

To compare (99m)Tc-depreotide and (201)Tl chloride SPET in the characterization of pulmonary lesions.. Fifty-seven pulmonary lesions from 33 patients suspected of malignancy in computed tomography, were assessed by (99m)Tc-depreotide and (201)Tl early and delayed SPET imaging. Images were visually assessed and the tumour-to-normal (T/N) lung activity ratio for early (ER) and delayed (DR) scans and the retention index (RI), were calculated in every lesion. A final diagnosis was reached for all lesions, based either on histology or prolonged clinical and radiological follow-up.. Twenty-three lesions were characterized as malignant and 34 benign. In visual analysis, all malignant lesions accumulated both tracers resulting in sensitivity and negative predictive values of 100%. However, false positive interpretations resulted in a specificity of 64.7% and 67.6% for (99m)Tc-depreotide and (201)Tl, respectively. ER and DR of both agents and the RI of (99m)Tc-depreotide were significantly higher in malignant, compared to benign lesions. In defining thresholds of abnormality from ROC analysis, a significant increase in specificity was observed for both tracers in both scan phases (91.2% for all), as compared to visual analysis (P<0.01). There was no significant difference in the diagnostic performance between (99m)Tc-depreotide DR and (201)Tl DR, although the former provided the highest T/N ratio.. This study demonstrates that (99m)Tc-depreotide and (201)Tl SPET are equally effective and may be useful in the non-invasive determination of lung malignancy. The specificity of both techniques is significantly improved by quantifying radiopharmaceutical accumulation in pulmonary lesions.

Topics: Adult; Aged; Aged, 80 and over; Female; Humans; Lung Neoplasms; Male; Middle Aged; Organotechnetium Compounds; Positron-Emission Tomography; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity; Solitary Pulmonary Nodule; Somatostatin; Thallium; Tomography, Emission-Computed, Single-Photon

Topics: Biopsy, Needle; Carcinoma, Bronchogenic; Carcinoma, Squamous Cell; False Negative Reactions; Humans; Lung Neoplasms; Male; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Radiography; Radiopharmaceuticals; Somatostatin; Thallium; Tomography, Emission-Computed, Single-Photon