^99mTc Gel Generators Based on Zirconium Molybdate-⁹⁹Mo: I. Process Standardisation for Production

Abstract

m Tc gel generators / Zirconium molybdate / Hot air drying / Process standardisation / Small scale production SummaryThe production of " m Tc gel generators based on zirconium molybdate-"Mo (Zr"Mo, ZrMo) presents a formidable challenge on account of the complex steps involved in gel processing. The critical step of drying the Zr"Mo cake was simplified using a regulated flow of air heated in a controlled manner to render the process amenable for remote handling. The success in thus drying the zirconium molybdate cake (about 30 g) led to the standardisation of a process for production of 5-10 gel columns per batch in a lead shielded plant adapting simple, ingenious techniques and using a prototype generator assembly developed for this purpose.

Experimental cross section evaluation for innovative 99Mo production via the (α,n) reaction on 96Zr target

“…The threshold energies of 100 Mo(p,p7n) and 96 Zr(a,7n) reactions are respectively 56.4 and 54.9 MeV [13]. However, in case of proton-induced reactions on 100 Mo targets, the 99 Mo separation from 100 Mo is not possible by chemistry, which results to low-SA product, forcing the use of alternative generator systems, such as gel generators [18][19][20][21], nanocrystalline column matrix generators [22] and large centralized generator facilities [23]. A 99m Tc concentration technique has also been proposed for large elution volume from low-SA generators [24].…”

Preparation of 99Mo from the 100Mo(γ, n) reaction and chemical separation of 99mTc

“…The 99m Tc-elution performance of the gel is assessed based on the following important factors: the 99m Tc elution efficiency, the 99 Mo breakthrough in the 99m Tc eluate, the gel synthesis conditions such as the molar ratios of zirconium to molybdenum, the drying conditions i.e. time, temperature, and atmosphere of the gel [40][41][42][43][44]. Variation of the photon energy could cause the formation of other radionuclides as impurities from the isotopes of zirconium and thus the shielding would have to be designed accordingly.…”

High radioactive concentration of 99mTc from a zirconium [99Mo]molybdate gel generator using an acidic alumina column for purification and concentration

“…Preparation of the zirconium [ 99 Mo]molybdate gel generator (n,g) 99 Mo was converted to an insoluble Zr 99 Mo matrix as reported previously [7,8], with the exception that the mole ratio of reactant Mo:Zr was 1:1.25 and the pH of the precipitate was adjusted to 4-5 with 4 N NaOH. The dried gel was disintegrated with normal saline, re-dried to free-flowing gel granules by passing hot air (B701C) and transferred to a glass column (35 Â 13 mm).…”

“…The column effluents were checked for the absence of chloride ions by using the AgNO 3 test. The 99 Mo breakthrough was tested by using the lead screen attenuation method [7,8,12].…”

“…The development of a user-friendly, column-type 99m Tc generator based on the conversion of (n,g) 99 Mo as a zirconium [ 99 Mo]molybdate (Zr 99 Mo) matrix and subsequent elution of 99m Tc from the Zr 99 Mo gel column with normal saline is a well explored attractive alternative [7][8][9][10][11]. We have demonstrated the good performance and applicability of such generators for hospital radiopharmacies [12].…”