We describe a simple method of pentavalent technetium-99m dimercaptosuccinic acid [99mTc(V)-DMSA] preparation for the imaging of medullary carcinoma of the thyroid using commercially available kits. 99mTc(V)-DMSA is available at high pH (approximately 7.5) by adding NaHCO3 solution in the presence of a small amount of reducing agent (SnCl2). On the other hand, trivalent 99mTc-DMSA [99mTc(III)-DMSA] can be obtained at low pH (below 3) in the presence of an excess amount of reducing agent. In the clinical evaluation of a patient with a medullary carcinoma of the thyroid, only 99mTc(V)-DMSA revealed an area of intense accumulation.

BACKGROUND: The authors prospectively evaluated the correlation between technetium‐99m methoxyisobutyl isonitrile (99mTc‐MIBI) accumulation in tumors and response to induction chemotherapy in patients with nasopharyngeal carcinoma (NPC). METHODS: Eighty‐six patients with locally advanced NPC underwent single‐photon emission computed tomography 15 minutes after an intravenous injection of 740 megabecquerels (20 mCi) 99mTc‐MIBI before chemotherapy. The tumor uptake ratio (TUR) was calculated. Two weeks after the second cycle of combined chemotherapy with 5‐fluorouracil (5‐FU) and cisplatin (DDP), the tumor response rate was evaluated. The correlation between 99mTc‐MIBI accumulation in tumors and response to chemotherapy with 5‐FU/DDP was examined. RESULTS: Positive accumulation of 99mTc‐MIBI in tumors was observed in 76 patients (88.4%). The tumor response was a complete response (CR) in 8 patients, a partial response (PR) in 68 patients, stable disease (SD) in 9 patients, and progressive disease (PD) in 1 patient. The response rate (CR and PR) to 5‐FU/DDP chemotherapy in patients who had positive 99mTc‐MIBI accumulation (tumor uptake ratio [TUR] >1.1) was higher than that in patients who had negative 99mTc‐MIBI accumulation (TUR ≤1.1; 98.7% vs 10%; P < .001). CONCLUSIONS: Patients with negative 99mTc‐MIBI accumulation were resistant to 5‐FU/DDP chemotherapy. 99mTc‐MIBI imaging in patients with NPC was capable of predicting tumor response to chemotherapy with 5‐FU/DDP and can help in the selection of patients for induction chemotherapy. Cancer 2011. © 2010 American Cancer Society.