Development of <sup>99</sup>Mo/<sup>99m</sup>Tc Generator System for Production of Medical Radionuclide <sup>99m</sup>Tc using a Neutron-activated <sup>99</sup>Mo and Zirconium Based Material (ZBM) as its Adsorbent

Abstract

Molybdenum produced from fission of U-235 is the most desirable precursor for 99 Mo/ 99m Tc generator system as it is non-carrier added and has high specific activity. However, in the last decade there has been short supply of 99 Mo due to several constrains. Therefore, there have been many works performed for development of 99 Mo/ 99m Tc generator system using 99 Mo which is not produced from either LEU or HEU. This report deals with development of 99 Mo/ 99m Tc generator system where zirconium-based material (ZBM) is used as adsorbent of neutron-activated 99 Mo. The system was prepared by firstly irradiating natural Mo in the G. A. Siwabessy reactor to produce neutron-activated 99 Mo. The target was dissolved in NaOH 4N and then neutralized with 12 M HCl. The 99Mo solution was then mixed with a certain amount of ZBM followed by heating at 90°C for three hours to allow the 99Mo adsorbed on ZBM. The 99Mo-ZBM (9.36 GBq of 99 Mo was Mo/ 4.2 g ZBM) was packed on a fritz-glass column. This column was then fitted serially with an alumina column for trapping 99 Mo breakthrough. The columns were then eluted daily with saline solution for up to one week. The yield of 99m Tc was found to be between 53.7 – 74% (n= 5). All 99m Tc eluates were clear solutions with pH of 5. Breakthrough of 99 Mo in 99m Tc eluates was found to be 0.031 ± 0.019 μCi 99 Mo/ mCi 99m Tc (n= 5) which was less than the maximum activity of 99 Mo allowed in 99m Tc solution (< 1 µCi 99 Mo/mCi 99m Tc). Aluminum breakthrough in 99m Tc eluates was found to be less than 10 ppm. The radiochemical purity of 99m Tc in form of Na 99m TcO 4 was > 99%. Radiolabeling of this 99m Tc towards methylene diphosphonate (MDP) kit gave a radiolabelling efficiency of 99%. In summary, a new 99 Mo/ 99m Tc generator system that used neutron-activated 99 Mo and ZBM as its adsorbent has been successfully prepared. The 99m Tc produced from this new 99 Mo/ 99m Tc generator system attained the quality of 99m Tc required for medical purposes. Received: 23 Februari 2016; Revised: 13 July 2016; Accepted: 17 July 2016