Dynamic scintigraphy with thallium-201 chloride (Tl-201) for the diagnosisof tumors of the head and neck

Objective. The purpose of this study was to differentiate between malignant tumors and benign tumors of the head and neck by means of thallium-201 chl oride scintigraphy. Study design. Thallium-201 chloride (Tl-201) scintigraphy and Ga-67 citrate (Ga-67) scintigraphy were performed in 10 patients with a benign tumor and in 90 patients with a malignant tumor. The blood flow index and the tumor retention index were obtained by means of Tl-201 scintigraphy. The blood fl ow index = the count of tumor/the count of control in the early dynamic sca n from 30 to 120 seconds after injection, and the tumor retention index = ( the count of tumor/the count of control in the delayed dynamic scan 2.5 hou rs after injection)/(the count of tumor/the count of control in the early d ynamic scan from 4 to 5 minutes after injection). Results. The early and delayed scans with Tl-201 demonstrated a very high c orrelation with the blood flow index. The tumor retention index had a tende ncy to increase in malignant tumors, especially in the poorly differentiate d tumors and the severely invasive tumors. Likewise, the tumor retention in dex decreased in benign tumors. These results proved to be statistically si gnificant, and in turn Tl-201 scintigraphy was deemed superior to Ga-67 sci ntigraphy. TI-201 scintigraphy was also useful in detecting small-size tumo rs. Conclusion. The tumor retention index of Tl-201 was useful for the differen tiation of malignant tumors of the head and neck from benign tumors of the same areas.