Diagnostic value of Thallium-201 scintigraphy in differentiating malignant bone tumors from benign bone lesions

Objective: This retrospective study aims to evaluate the diagnostic capacity of thallium-201 (201Tl) scintigraphy for differentiating malignant bone tumors from benign bone lesions. Methods: Between January 2006 and December 2012, 279 patients with bone lesions (51 malignant and 228 benign) underwent 201Tl scintigraphy before treatment. To evaluate 201Tl uptake, we investigated tumor-to-background contrast (TBC) as well as TBC washout rate (WR). The differences of TBC on early and delayed images and WR were estimated by the Mann–Whitney U test. Receiver operating characteristic (ROC) analyses were used to determine the cut-off TBC values for differentiating malignant bone tumors from benign bone lesions. Results: There were statistically significant differences in median TBC between malignant tumors and benign lesions. These differences occurred for early imaging (1.57 vs. 0.09, p < 0.001) as well as for delayed imaging (0.83 vs. 0.07, p < 0.001). However, there was no statistical difference in WR between malignant tumors and benign lesions (44 vs. 43 %, NS). The chosen TBC cut-off value was 0.68 for early imaging and 0.38 for delayed imaging. Using these cut-off values, the prediction of malignancy had a 77 % sensitivity, 74 % specificity, and 75 % accuracy for early imaging and an 80 % sensitivity, 76 % specificity, and 77 % accuracy for delayed imaging. Conclusions: 201Tl scintigraphy may have the ability to distinguish malignant bone tumors from benign bone lesions.