A new solvent-extraction module for a local routine production of technetium-99m by medical cyclotrons

Background-aim: 99mTc is usually supplied to hospitals through a 99Mo/99mTc generator where it is generated from the decay of the parent nuclide 99Mo (t = 66 h), which is produced in nuclear reactors via neutron fission. The interruption of the global supply chain of reactor-produced 99Mo occurred in 2009–2010, has forced the scientific community to investigate alternative production routes for 99mTc. One solution was to consider cyclotron-based methods as potential replacement of reactor-based technology and the nuclear reaction 100Mo(p,2n)99mTc emerged as the most worthwhile approach.In this work we describe the evolution of a remotely controlled prototype previously developed for extraction and purification of 99mTc from an irradiated metallic 100Mo using medical cyclotrons. The new system set up was in particularly designed with the aim to process both foils configuration target and standard solid target (backing material like copper, gold, tantalum or other) compatible with conventional medical cyclotron. Methods: 100Mo metallic targets were irradiated using the 16.5 MeV GE PETtrace cyclotron at the University Hospital of Bologna, for 1.5 h with a proton beam current of 20 microA with an entrance energy of 15.7 MeV. The target was then transferred into the reactor vial of the automated module and a separation and purification procedure, based on solvent extraction with MEK was started. The use of MEK caused the selective extraction of 99mTcO4 -. To enhance the efficiency of the extraction process, vigorous bubbling was introduced by passing ahelium stream through the mixture in a special glass column, 15 cm in length and 1 cm in diameter, especially designed and handmade. Results: The overall separation process lasted for approximately 70 min and recovery of the initial activity from the target was about 93%. Radionuclidic purity of the final 99mTcO4 - was 99.7 ± 0.2%. The automated module has the possibility to fully integrate into the module the dissolution process of the irradiated Mo-100 metallic target. This option can dramatically decrease operator’s exposure to potentially huge amounts of radioactivity. Conclusions: In the perspective to stimulate a local routine production of sodium 99mTc-pertechnetate by in-house low-energy and low current medical cyclotrons, it was reported here the development of an easy-to-make and cost-effective automated module for the extraction of Tc-99m from proton-irradiated Mo-100 enriched metallic targets. According to pharmaceutical standards, the quality of the resulting 99mTcO4- was adequate for clinical applications.