New strategies for a sustainable 99mTc supply to meet increasing medical demands: Promising solutions for current problems

The continuing rapid expansion of ^99mTc diagnostic agents always calls for scaling up ^99mTc production to cover increasing clinical demand. Nevertheless, ^99mTc availability depends mainly on the fission-produced ⁹⁹Mo supply. This supply is seriously influenced during renewed emergency periods, such as the past ⁹⁹Mo production crisis or the current COVID-19 pandemic. Consequently, these interruptions have promoted the need for ^99mTc production through alternative strategies capable of providing clinical-grade ^99mTc with high purity. In the light of this context, this review illustrates diverse production routes that either have commercially been used or new strategies that offer potential solutions to promote a rapid production growth of ^99mTc. These techniques have been selected, highlighted, and evaluated to imply their impact on developing ^99mTc production. Furthermore, their advantages and limitations, current situation, and long-term perspective were also discussed. It appears that, on the one hand, careful attention needs to be devoted to enhancing the ⁹⁹Mo economy. It can be achieved by utilizing ⁹⁸Mo neutron activation in commercial nuclear power reactors and using accelerator-based ⁹⁹Mo production, especially the photonuclear transmutation strategy. On the other hand, more research efforts should be devoted to widening the utility of ⁹⁹Mo/^99mTc generators, which incorporate nanomaterial-based sorbents and promote their development, validation, and full automization in the near future. These strategies are expected to play a vital role in providing sufficient clinical-grade ^99mTc, resulting in a reasonable cost per patient dose.

Sorption Profile of Low Specific Activity 99Mo on Nanoceria-Based Sorbents for the Development of 99mTc Generators: Kinetics, Equilibrium, and Thermodynamic Studies

⁹⁹Mo/^99mTc generators play a significant role in supplying ^99mTc for diagnostic interventions in nuclear medicine. However, the applicability of using low specific activity (LSA) ⁹⁹Mo asks for sorbents with high sorption capacity. Herein, this study aims to evaluate the sorption behavior of LSA ⁹⁹Mo towards several CeO₂ nano-sorbents developed in our laboratory. These nanomaterials were prepared by wet chemical precipitation (CP) and hydrothermal (HT) approaches. Then, they were characterized using XRD, BET, FE-SEM, and zeta potential measurements. Additionally, we evaluated the sorption profile of carrier-added (CA) ⁹⁹Mo onto each material under different experimental parameters. These parameters include pH, initial concentration of molybdate solution, contact time, and temperature. Furthermore, the maximum sorption capacities were evaluated. The results reveal that out of the synthesized CeO₂ nanoparticles (NPs) materials, the sorption capacity of HT-1 and CP-2 reach 192 ± 10 and 184 ± 12 mg Mo·g^–1, respectively. For both materials, the sorption kinetics and isotherm data agree with the Elovich and Freundlich models, respectively. Moreover, the diffusion study demonstrates that the sorption processes can be described by pore diffusion (for HT-synthesis route 1) and film diffusion (for CP-synthesis route 2). Furthermore, the thermodynamic parameters indicate that the Mo sorption onto both materials is a spontaneous and endothermic process. Consequently, it appears that HT-1 and CP-2 have favorable sorption profiles and high sorption capacities for CA-⁹⁹Mo. Therefore, they are potential candidates for producing a ⁹⁹Mo/^99mTc radionuclide generator by using LSA ⁹⁹Mo.

99Mo/99mTc radioisotope generator based on adsorption of 99Mo (VI) on cerium (IV) molybdate column matrix

Based on neutron activated 99Mo, a procedure for preparation of 99Mo/99mTc radioisotope generator was developed. Batch equilibration method was used to investigate the sorption behavior of Mo (VI) (10−4 M) in chloride and nitrate solutions on cerium (IV) molybdate gel matrix using 99Mo radiotracer. The breakthrough sorption capacity of cerium molybdate gel matrix for 99Mo (VI) (3×10−2 M) were found to be 0.54 mmol/g of the sorbent [1 g column (0.6 cm i.d.)]. Elution performance of the generated 99mTc from cerium molybdate-99Mo chromatographic column was investigated as a function of inside diameter of the column, amount of the bed matrix and flow rate of the eluent. Based on the obtained results, 99Mo/99mTc radioisotope generator was prepared based on adsorption of neutron activated 99Mo (VI) of low specific activity onto chromatographic columns packed with 5 g cerium molybdate gel matrix. The radioactivity of 99mTc is periodically eluted with 10 mL 0.9% NaCl solution at a flow rate of 1 mL/min. Elution yield of 78±5% was obtained with high chemical, radionuclidic (99Mo breakthrough 1×10−3±0.3×10−3%) and radiochemical purity (97±2%).

Synthesis and characterization of a ZnMn2O4nanostructure as a chemical nanosensor: a facile and new approach for colorimetric determination of omeprazole and lansoprazole drugs

ZnMn₂O₄nanostructure was preparedviaan auto-combustion method using different fuels, and it was used as a chemical sensor for determination of omeprazole and lansoprazole drugs.

Tunable auto-combustion preparation of TiO2nanostructures as efficient adsorbents for the removal of an anionic textile dye

We have developed a new route for the synthesis of pure TiO₂nanostructuresviaa facile auto-combustion method followed by heat treatment.

A facile Pechini sol–gel synthesis of TiO2/Zn2TiO2/ZnO/C nanocomposite: an efficient catalyst for the photocatalytic degradation of Orange G textile dye

We have developed an efficient route for the synthesis of TiO₂/Zn₂TiO₂/ZnO/C nanocomposites through a Pechini sol–gel method followed by heat treatment at 550 °C for 30 min.

Preparation of diethylenetriamine-modified magnetic chitosan nanoparticles for adsorption of rare-earth metal ions

The development of a sustainable method to conveniently separate rare-earth metal ions remains a challenge waiting for breakthrough in numerous of advanced technologies.

n-Capric acid-anchored silanized silica gel: its application to sample clean-up of Th(iv) sorbed as a dinuclear species in quantified H-bonded dimeric metal-trapping cores

nCA anchored to SSG surface generates 121 μM g⁻¹ H-bonded metal-trapping cores with 10-fold increase in surface area for selective uptake of {Th₂(OH)₂(H₂O)₂}⁶⁺.