Diagnostic value of early and delayed 201Tl thyroid scintigraphy in the evaluation of cold nodules for malignancy

We performed 201Tl thyroid scintigraphy using an early and delayed scanning technique in 34 patients exhibiting cold nodules on 99mTc scans. Of the 29 benign nodules, 27 were correctly diagnosed as being negative, i.e. 93% specificity. However, two of five malignant nodules failed to concentrate activity on both the early and delayed scans. The low sensitivity (60%) of this method for detecting carcinomas limits its clinical value in the routine diagnostic work-up of patients with suspected thyroid cancer. Our findings are in contrast to previous more optimistic reports.