Cyclotron production of technetium radionuclides using a natural metallic molybdenum thick target and consequent preparation of [Tc]-BRIDA as a radio-labelled kit sample

Numerous studies have focused on the use of accelerators for production of 99mTc, but all of these investigations have been performed at low-level currents. In this research, for the first time, we have constructed a high power level natural Mo target for production of 99mTc radioisotope using cyclotrons. A high purity natural molybdenum target (130 mg/cm2), suitable for proton beam power level of several kilowatts, has been constructed using a thermal spray coating method. The target was irradiated in a Cyclone30 accelerator using 160 mi A of 25 MeV proton beam energy for 1000 mi A-h. The activity of produced 99mTc was measured as 2.75 Ci. The technetium radionuclides produced were extracted using an MEK organic phase, followed by preparation of Tc-BRIDA as a radio-labelled kit sample. Animal biodistribution studies have been performed in rats. After administration of the radio-labelled Tc-BRIDA in rats, we observed most of the radioactivity accumulated in intestine as expected for IDA derivatives. The results of measurements show a successful production of Tc radionuclides (including 99mTc) in the bombarded target and subsequent labelling of the kit with Tc. It is anticipated that the developed coating method for the production of high power Mo targets using enriched 100Mo and a proton beam of about 1 mA is capable of producing about 100 Ci of 99mTc per irradiated target. The developed high power Mo target, if constructed using enriched 100Mo, could be a practical method for a large-scale production of 99mTc for local applications near cyclotron facilities.