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Generally, short-lived medical isotopes and/or their generators are produced in nuclear reactors and cyclotrons. During the last decade, the rapidly increasing number of the studies on the photonuclear method of production of these isotopes has been observed. Experimental data on the production of ten radiometals (99Mo/99mTc, 47Sc, 67Cu, 225Ac, 177Lu, 44Ti/44Sc, 111In, 105Rh, 68Ge/68Ga, 188Re) in electron accelerators is presented in this review. The advantages of the photonuclear method for several isotopes were demonstrated, its future was discussed.

Nanodiamonds (NDs) were investigated as potential carriers of 99mTc, which is widely used for the diagnosis of diseases in nuclear medicine. The sorption of 99Tc(VII), 99mTc(VII), and 99mTc(IV) by commercial NDs and their reduced, aminated, and oxidized forms was studied. The physicochemical parameters of the Langmuir and Freundlich isotherms for the sorption of 99Tc(VII) by the used ND samples were determined. The Sn(II): Tc(VII) ratio for the quantitative reduction of Tc to the oxidation state IV was optimized. It was shown that the initial (commercial) and oxidized NDs are promising carriers of 99mTc(IV) for nuclear medicine.

The sorption behavior of 89Zr on hydroxyapatite (Ca10(PO4)5(OH)2, HA) nanoparticles in an aqueous medium and 0.9% NaCl at various pH values was studied. The fast kinetics of the process was determined; the stability of the obtained conjugate in a model biological medium at 25 and 37 °C was shown. The possibility of further use of the 89Zr@HA conjugate in various radiopharmaceuticals is discussed.

A method has been developed for isolation of 228Ac from aged samples of natural 232Th. Macroscopic amounts of the thorium bulk (20 g) were separated by its extraction by a solution of di(2-ethylhexyl)phosphoric acid in toluene from 4 M HNO3 solutions, with microamounts of 228Ra and 228Ac remaining in the aqueous phase. 228Ac was selectively extracted from the resulting solution by the method of extraction chromatography on a column with RE resin sorbent, and 228Ra quantitatively remained in the 4 M HNO3 eluate. 228Ac was washed out of the column with 0.05 M HNO3, it could be used as a radioisotope for research purposes. After the accumulation of the daughter 228Ac the solution of 228Ra in 4 M HNO3 was repeatedly passed through an identical column. The resulting 228Ac was used in the study to examine its sorption on commercial and modified carbon nanomaterials (CNMs) instead of the difficultly accessible 225Ac. It is shown that the application of CNMs as carriers of actinium isotopes for nuclear medicine purposes is promising.

A new method for separation of 97Ru radionuclide from irradiated by a-particles molybdenum, which potentially could be applied in nuclear medicine, is proposed. Carrier-free ruthenium-97 was separated from macroamounts of molybdenum and trace amounts of technetium by extraction chromatography on a commercial DGA sorbent. The distribution of 97Ru in the body organs of mice was studied.

A new method of production of one of the most widely used isotopes in nuclear medicine

The behavior of group-4 homologs Zr and Hf on extraction-chromatographic sorbents LN resin and TRU resin in mixtures of HF and HNO3 is considered. Distribution coefficients of the elements in the mixtures of 5·10−4 M–1 M HF and 0.01 M–5 M HNO3 are determined. Strong retention of both elements was found on LN resin in the range of concentrations c(HF) ≤ 0.01 M for all concentrations of HNO3. Retention tends to gradually disappear while increasing c(HF) to 0.5 M. On TRU resin retention is observed only in solutions with c(HNO3) ≥ 2 M and c(HF) ≤ 0.01 M. The possibility of separating Zr(IV) and Hf(IV) on LN resin is illustrated in two different acid mixtures, whereas their separation on TRU resin under the conditions studied in this work is difficult. The results obtained can be used to isolate analytes from multicomponent mixtures during analytical tasks, as well as to separate them from each other.

Elemental and phase composition of hydroxyapatite (HA) nanoparticle surface with absorbed zirconium were studied with X-ray photoelectron spectroscopy. Zr4+ adsorption on HA nanocrystals as a function of hydrochloric solution pH was established. The mechanism of interaction of zirconium with the HA surface was discussed. The obtained results are fundamental for 89Zr-based radiopharmaceuticals with a new design.

Production of medical radionuclide 67Cu by the irradiation of Zn of natural isotopic composition by bremsstrahlung photons of maximum energy of 55 MeV was studied. Production yields of 67Cu and other activation products were determined. The yield of 67Cu is (2.34 ± 0.07) × 105 Bq/(μA h g/cm2) at EOB. The experimental data were compared with the results of other experiments and theoretical calculations based on the statistical model in the TALYS software and on the combined model of photonuclear reactions. Technique of chemical separation of 67Cu from irradiated zinc target based on extraction chromatography using CU Resin was applied. Radiochemical yield was > 95%, separation time was 1 h. The possibility of production of medical quantities was discussed.

The efficiency of tritium labeling of salts of pantothenic (HO–R–COOH), hopantenic (HO–R–CH2–COOH), and 4-D-phosphopantothenic [(HO)2P(=O)–O–R–COOH] acids [R = CH2C(CH3)2CHOH–CONH(CH2)2] with thermal activation of tritium at target temperatures of 77 and 295 K was studied. The phosphate group inhibits the isotope exchange. The tritium-labeled compounds were used for studying the adsorption of pantothenic acid derivatives from aqueous solutions and in the presence of 0.9% NaCl at 297 ± 3 K onto nanodiamonds prepared by detonation synthesis (NDs). Preparation of stable ND suspensions in advance enhances the ability of NDs to adsorb the compounds studied. The parameters of the equation describing the sorption isotherms at different ionic strengths of the solution were calculated. The strength of the adsorbate retention in contact with water, 0.9% NaCl solution, 0.01 M HCl solution, and 40 g L−1 bovine serum albumin (BSA) solution was determined. The data obtained allow two mechanisms of the adsorbate retention on the ND surface to be considered: reversible adsorption due to ionic interactions and irreversible binding due to hydrophobic interactions. The strongly bound molecules undergo slow desorption in the presence of BSA. The revealed trends confirm high potential of NDs as a drug delivery platform.

The article discusses the features of the development of shedding processes on the slopes composed of siltstones within the right bank of the Votkinsk reservoir.

The possibility of production a medical radionuclide 177Lu by irradiating natHfO2 by bremsstrahlung photons up to 55 MeV was investigated. The yields of the main nuclear reactions were measured. A procedure for one-step separation of carrier free 177Lu via extraction chromatography on the LN resin sorbent (Triskem) was developed. The radiochemical yield was 98%, separation factor was higher than 105. Isomeric ratio 177mLu/177Lu was estimated. Simulation of 177Lu production in photonuclear reactions on 178Hf, 179Hf and natHf nuclei was performed. The possibility of production of medical quantities was discussed.

In this work, the separation of 89Zr, a radionuclide promising for positron-emission tomography, from an irradiated yttrium target using different extraction-chromatographic resins (TEVA, UTEVA, TRU, and LN resins ©Triskem) was studied. Distribution coefficients of Zr(IV) onto TEVA, LN (in HCl solutions), and onto TRU (in HCl and HNO3) were determined. The optimum conditions for the separation of Zr(IV) and Y(III) using these resins were proposed. In each case, the maximum separation factor was higher than 105. The developed separation procedures allow to obtain 89Zr of high radiochemical purity for dilute mineral acids.

A method for obtaining 156, 155, 154m2, 154, 153Tb radiotracers by the irradiation of a europium oxide target of natural isotopic composition by 27 MeV α-particles is proposed. Terbium can be efficiently separated from bulk of europium by the reduction of the latter by zinc in an acidic solution and precipitation as EuSO4. The optimum Zn/Eu3+ and (NH4)2SO4/Eu3+ molar ratios are 20 and 3, respectively. Terbium is additionally purified from europium and gadolinium by extraction chromatography using LN Resin. It is demonstrated that optimum separation is attained in 0.6 M HNO3. The Tb/Eu separation coefficient was ~5·105. The yield of terbium was about 90%. Time of all steps was 1.5–2 h. The proposed procedure makes it possible to obtain no carrier added terbium radiotracers.

In this study, the possibility of application of carbon nanomaterials (CNMs) as carriers of various isotopes for nuclear medicine is investigated. The sorption of 99mTc, 207Bi (as analog for 213Bi), 90Y, and 226Ra (as analog for 223Ra) in aqueous solutions with pH 6 and 0.01 M phosphate-buffered saline with pH 7 was studied on the following CNMs samples: detonation nanodiamonds (NDs), reduced graphite oxide (rGiO), and multi-walled nanotubes (MWCNTs). Commercial, hydrogenated, and aminated ND and hydrogenated MWCNTs adsorb Tc(VII) by 40–70%; however, in physiological saline, it is readily desorbed within 0.5 h. The sorption of Tc(IV) on commercial and carboxylated ND, as well as rGiO, was 60–90%. In this case, desorption in the biological media did not exceed 5% for each sample in 5 h. The sorption of Bi(III) on all the samples studied was from 80% to 100%, and the Bi(III)@ND conjugate was the most stable, as its desorption in the model biological medium was 4% for 5 h. It was shown that the sorption and desorption for Y(III) differs significantly depending on the CNM sample used, thereby allowing for the selection of the conditions for the use of Y(III)@CNMs conjugate for specific medical tasks. It was found that Ra(II) sorption occurs only on the rGiO sample and reaches 60%; however, depending on the medium, desorption was from 35% to 70% in 30 min, thereby complicating the use of the Ra(II)@rGiO conjugate. The data regarding sorption behavior and stability in biological media of the studied isotopes on CNMs allow us to not only choose the conditions for their effective use in nuclear medicine, but also evaluate the sorption behavior of other nuclear medicine isotopes.