Differentiation between malignant and benign solitary thyroid nodules by fluorescent scanning.

A quantitative fluorescent technique has been developed for making in vivo iodine content determinations of the total thyroid gland or of selected parts. In solitary thyroid nodules "cold" to radionuclide studies, the ratio of iodine content in the nodule to that in a corresponding area of the contralateral lobe has proven to be a good indicator of malignancy. In a preliminary study of 42 surgical patients, an iodine content ratio (ICR) below 0.60 (chosen a posteriori) proved to be an excellent indication of malignancy with a sensitivity of 100%, a specificity (predictive value) of 79%, and an overall accuracy of 90%. Further definitive studies are needed to verify these preliminary observations.