PT - JOURNAL ARTICLE AU - Zhang, Zhuangyu AU - Lipszyc, Helena AU - Zaretsky, Victor AU - Knesaurek, Karin AU - Machac, Josef TI - A fast kit preparation of <sup>123/131</sup>I-MIBG by microwave heating DP - 2006 May 01 TA - Journal of Nuclear Medicine PG - 522P--522P VI - 47 IP - suppl 1 4099 - http://jnm.snmjournals.org/content/47/suppl_1/522P.2.short 4100 - http://jnm.snmjournals.org/content/47/suppl_1/522P.2.full SO - J Nucl Med2006 May 01; 47 AB - 1899 Objectives: 123/131I-MIBG can be synthesized by the following nucleophilic exchange reactions: Cu2+ catalyzed reactions in aqueous medium, (NH4)2SO4 solid state transfer catalyst method, reaction in the pseudo melt phase in absence of any catalyst, and a Cu+ assisted reaction. Most of these reactions use high reaction temperature and long heating time. Under these reaction conditions, both radiochemical purity and labeling efficiency are reduced. The Cu+ assisted nucleophilic exchange reaction is the mildest one; we have used it to prepare 123I-MIBG. When heated at 100°C for 30-40 min, the radiochemical yield is &gt; 99%. Microwave heating has been used to accelerate chemical reactions. We hypothesized that microwave heating may be used for rapid preparation of radioiodinated MIBG. We set out to prepare 123/131I-MIBG using the Cu+ assisted kit method and microwave heating. Methods: To a septum closed v-vial containing 1 mg cold MIBG, 25 μg CuSO4.5H2O and an excess of reducing agents (0.4 mg SnSO4, 5 mg gentisic acid) in 0.5 ml oxygen-free water, was added 0.1-0.5 ml of oxygen free 123/131I NaI solution (MDS Nordion, ON, Canada, or Mallickrodt, MO, USA) containing the required activity. The vial was heated in a domestic microwave oven (Kenmore, Model 565,8824581, 2450MHz, 1580W) for 3 min. The labeling efficiency and radiochemical purity were determined by HPLC using μBondPak C18 3.9×300 mm column (Waters Corporation, MA, USA), 0.1%H3PO4/EtOH (80:20) as the mobile phase, and monitoring by UV and radiation detectors. Results: When the reaction vial was heated in the domestic microwave oven for 3 min, the labeling efficiency was ~100%, and the radiochemical purity was ~100%. Due to the shorter heating time, the microwave heating method significantly reduces radiochemical and chemical impurities. Conclusions: 123/131I-MIBG can be quickly prepared in 3 min using microwave-assisted heating with very high radiochemical purity and very high labeling efficiency. Microwave-assisted heating is expected to extend to the preparation of other 123/125/131I radiopharmaceuticals using the Cu+ assisted kit method.