Introduction: Radiolanthanides 132La and 135La form a promising chemically matched theranostic pair. With a half-life of 18.95 h, 135La acts as the therapeutic isotope as it releases approximately 11 Auger electrons per decay, making it compatible with targeted Auger electron therapy (TAET), whereas 132La with half-life of 4.58 h undergoes positron emission making it compatible with imaging via positron emission tomography (PET). Methods: 132/135La were produced via irradiation of natural barium targets (99.9 %) with 12.8 MeV protons. A two-step separation scheme using extraction chromatographic resin TK200 (50-100 mu m) and cation exchange resin Dowex 50Wx4 (200-400 mesh) was designed. Inductively coupled plasma mass spectrometry (ICP-MS) was used to quantify non-radioactive impurities in each fraction of the separation method. The distribution coefficients of La3+ in HNO3 on the TK200 resin and on both Dowex 50Wx8 (200-400 mesh) and Dowex 50Wx4 resins in ammonium alpha-hydroxyisobutyrate (pH 4.8) were determined, respectively. Results: This novel separation scheme allowed for reliable separation of [132/135La]La3+ from the Ba2+ target material, resulting in a high radiochemical yield of 98.3 +/- 2.1 % (n = 3) with the final elute being directly compatible with subsequent radiolabeling due to the use of ammonium alpha-hydroxyisobutyrate to eliminate steps in the radiopharmaceutical synthetic process.

The paper introduces two reverse-tandem schemes of the 140 Ba → 140 La radionuclide generator which allow obtaining the daughter radionuclide 140 La for different applications in nuclear spectroscopy and as a tracer for radiochemical separations. The tandem generator system includes two stages: a chromatographic separation of parent and daughter radionuclides based on the main reverse column (cation-exchange column), and purification based on tandem column (extraction column). The main chromatographic separation is carried out in acetic acid media. Use of 140 La preparation with high specific activity in the perturbed angular γγ-correlation method is discussed.

Targeted Alpha Therapy (TAT) holds significant promise as a localized treatment for cancer. Encouraging clinical results from using peptides and antibodies labeled with alpha emitters to treat patients with metastatic cancers, particularly those who have not responded to other therapies, provide compelling evidence of TAT's potential. To fully realize the benefits of TAT, it is essential to carefully select appropriate radionuclides and targeting delivery systems to maximize therapeutic efficacy while minimizing nonspecific toxicity to healthy tissues. This review explores key radiochemical, radiopharmaceutical, and radiation-biological considerations for current TAT candidates, and proposes additional potential candidates, establishing a foundation and criteria for the ongoing development of TAT radiopharmaceuticals.

The SuperNEMO experiment is searching for neutrinoless double-beta-decay of Se-82, with the unique combination of a tracking detector and a segmented calorimeter. This feature allows us to detect the two electrons emitted in the decay and measure their individual energies and angular distribution. The SuperNEMO Demonstrator's calorimeter consists of 712 plastic scintillator blocks read out by large PMTs. Having constructed the calorimeter underground, we performed its first commissioning using gamma-rays from calibration sources or from the ambient radioactivity background. This article presents quality assurance tests of the SuperNEMO Demonstrator's calorimeter, and its first time and energy calibrations with gamma-rays, along with the associated methods. A time alignment of about 120 ps and a time resolution around 615 ps have been achieved. Concerning the energy, an alignment of 7.5% has been obtained. These results will be further improved when associating the tracking detector and detecting electrons from calibration sources.

44gSc presents a particular interest for application in nuclear medicine for positron emission tomography (PET) due to its favorable nuclear decay properties (t1/2 = 3.97 h, Emax = 1.47 MeV, branching ratio 94.3% β+). Its nuclear isomer 44mSc (t1/2 = 58.61 h) decays by isomeric transition (IT) into 44gSc, accompanied by ≈12% of conversion electron emission, which can cause a partial release of the daughter 44gSc from the chelate complex. A 13 MeV cyclotron at TRIUMF was used to produce both 44mSc and 44gSc via the natCa(p,n)44m,gSc reaction. A 44mSc/44gSc generator was designed by using a Strata C-18E cartridge. After several tested systems, a successful separation method was developed using DOTATOC as a chelator, a Strata C-18E cartridge as a generator column, and an elution solution of 0.1 M NH4-α-HIB. The yield of the generator with the daughter 44gSc release was equal to 9.8 ± 1.0% (or ≈80% per portion of conversion). This result shows the important role of after-effects in the design of radionuclide generators. Nuclear cross-section calculations were applied using the TALYS code to allow for the determination of the most promising alternative routes for 44mSc production, which will enable the development of a full-scale 44mSc/44gSc radionuclide generator based on after-effects.

In recent years, radiopharmaceuticals have been increasingly used for diagnostics and treatment of cancer. In addition to a biological vector, a modern radiopharmaceutical includes a chelator that binds the radionuclide, as well as a linker for connecting the vector and the chelator. The development of such an approach requires the improvement of methods for obtaining and purifying radionuclides, and the development of methods for the synthesis of radiopharmaceuticals, i.e., preparative direction. It is also necessary to search for new vectors and chelators. This implies the development of methods for analyzing the properties of radiopharmaceuticals in general, as well as their precursors, i.e., analytical direction. In this review, we describe the prerequisites for successfully solving a wide range of challenges in these two areas of nuclear medicine at the Scientific and Experimental Department of Nuclear Spectroscopy and Radiochemistry of the Laboratory of Nuclear Problems of the Joint Institute for Nuclear Research (LNP JINR). These prerequisites are due to rich experience in obtaining the widest range of radionuclides and their application for various spectrometric studies. Both the past and present works on radiopharmaceutical topics carried out in the department are described, and ways of future development are outlined.

The DANSS detector is located directly under the nuclear reactor at the Kalinin nuclear power plant. Such a position ensures about 50 m.w.e. shielding from cosmic rays in the vertical direction; as a result, the detector occupies an intermediate position between surface and underground detectors in the shielding from cosmic rays. The sensitive volume of the detector consisting of a 1-m 3 plastic scintillator is surrounded by the multilayer passive shielding and muon veto. The main aim of the DANSS experiment is to measure the antineutrino spectrum at various distances from the source. To this end, the detector is placed on a lifting platform in order to record data at three positions of 10.9, 11.9, and 12.9 m from the reactor core. The detector can reconstruct muon tracks passing through its sensitive volume. The pressure, temperature, and decay coefficients for muons in various regions of the zenith angle θ have been determined from the muon data collected during four years using the effective generation level method.

Targeted Meitner-Auger Therapy (TMAT) has potential for personalized treatment thanks to its subcellular dosimetric selectivity, which is distinct from the dosimetry of β- and α particle emission based Targeted Radionuclide Therapy (TRT). To date, most clinical and preclinical TMAT studies have used commercially available radionuclides. These studies showed promising results despite using radionuclides with theoretically suboptimal photon to electron ratios, decay kinetics, and electron emission spectra. Studies using radionuclides whose decay characteristics are considered more optimal are therefore important for evaluation of the full potential of Meitner-Auger therapy; 119Sb is among the best such candidates. In the present work, we develop radiochemical purification of 120Sb from irradiated natural tin targets for TMAT studies with 119Sb.

The geometry of dendritic spines has a major impact on signal transmission at excitatory synapses. To study it in detail we raised transgenic mice expressing an intrinsic green fluorescent protein-based plasma membrane marker that directly visualizes the cell surface of living neurons throughout the brain. Confocal imaging of developing hippocampal slices showed that as dendrites mature they switch from producing labile filopodia and polymorphic spine precursors to dendritic spines with morphologies similar to those reported from studies of adult brain. In images of live dendrites these mature spines are fundamentally stable structures, but retain morphological plasticity in the form of actin-rich lamellipodia at the tips of spine heads. In live mature dendrites up to 50% of spines had cup-shaped heads with prominent terminal lamellipodia whose motility produced constant alterations in the detailed geometry of the synaptic contact zone. The partial enveloping of presynaptic terminals by these cup-shaped spines coupled with rapid actin-driven changes in their shape may operate to fine-tune receptor distribution and neurotransmitter cross-talk at excitatory synapses.

To find a high purity flux for low background experiments is one of the most challenging problems. In this work, we report the production process of a highly purified ammonium acetate flux solution for low background experiments. A sub-distilled method has been used to purify initial precursors from contamination for the syntheses of final product. As a result, a high purity ammonium acetate solution was synthesized with a minimum content of elements which collectively represent the main source of background radiation (K  < 2.3 × 10–8 g/g, Th  < 2.6 × 10–11 g/g and U  < 1 × 10–11 g/g). An Estimation of the impurity content of the product has been performed with Instrumental neutron activation analysis, inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry.

The 9.2 keV nuclear transition in 227Th was studied in the β−-decay of 227Ac by means of the internal conversion electron spectroscopy to clarify the spin-parity assignment of the ground state and the two lowest excited states of 227Th. The transition multipolarity was proved to be of mixed character M1 + E2 and the spectroscopic admixture parameter δ2(E2/M1)=0.695±0.248 (|δ(E2/M1)|=0.834±0.149) was determined. Nonzero value of δ(E2/M1) questioned the present theoretical interpretation of low-lying levels of 227Th. Calculations performed prefer the 1/2+, 3/2+, and 3/2+ sequence instead of the adopted 1/2+, 5/2+ and 3/2+ one for the 0.0, 9.2, and 24.3 keV levels, respectively.

The 9.2 and 24.3 keV nuclear transitions in $$^{\mathrm {227}}$$ Th were studied in the $$\upbeta ^{-}$$ decay of $$^{\mathrm {227}}$$ Ac employing the internal conversion electron spectroscopy. Values of $$(9244.6 \pm 0.8)$$ and $$(24343.1 \pm 1.1)$$ eV were determined for their energies. The 24.3 keV transition was found to be of the mixed (M1 $$+$$ E2) multipolarity with the spectroscopic admixture parameter $$\delta ^{\mathrm {2}}$$ $$(E2/M1)$$ = $$(0.0116 \pm 0.0004)$$ . Energies of $$(24342.9 \pm 1.2)$$ , $$(28613.3 \pm 1.7)$$ , and $$(37860.2 \pm 2.0)$$ eV were obtained respectively for the 24.3, 28.6, and 37.8 keV transitions in $$^{\mathrm {227}}$$ Th by means of the gamma-ray spectroscopy. Natural atomic-level widths of $$(14.1 \pm 0.5)$$ , $$(11.4 \pm 0.5)$$ , $$(6.9 \pm 0.4)$$ , $$(11.4 \pm 1.4)$$ , $$(8.6\pm 1.2)$$ , and $$(6.0 \pm 0.7)$$ eV for the M $$_{\mathrm {1}}$$ -, M $$_{\mathrm {2}}$$ -, M $$_{\mathrm {3}}$$ -, N $$_{\mathrm {1}}$$ -, N $$_{\mathrm {2}}$$ -, and N $$_{\mathrm {3}}$$ -subshells of thorium, respectively, were derived from conversion electron lines. The cross checking of the energy values of the 9.2, 15.1, and 24.3 keV nuclear transitions obtained by the ICES method is also given.

Radiochemical separation and purification play an important role in the production and synthesis of radiopharmaceuticals in modern nuclear medicine. Several important criteria that need to be considered when choosing appropriate radiochemical separation methods are discussed in the present work. This review is designed to give an overview of important aspects of radiochemical separation for medical radionuclides and to bridge it with their production and chelation. Several important parameters, such as radionuclidic and radiochemical purity, specific activity are discussed. With this review, the authors would like to stress the importance of radiochemistry for radiopharmaceutical science, as it is very often underestimated.

Targeted Auger Therapy represents great potential for the therapy of diseases which require a high degree of selectivity on the cellular level (e.g. for therapy of metastatic cancers). Due to their high Linear Energy Transfer (LET), Auger emitters, combined with selective biological systems which enable delivery of radionuclides close to the DNA of the targeting cell, can be extremely selective and powerful treatment tools. There are two main aspects associated with the development of efficient radiopharmaceuticals based on Auger Emitters: a) the availability of suitable Auger-emitting radionuclides for therapy and b) the design of targeting vectors which can deliver Auger emitters into/close to the nucleus. In the present review, we address the first aspect by defining important parameters for the selection of radionuclides for application to Targeted Auger Therapy and form a categorized list of the most promising radionuclides, their possible production routes, and their use in the synthesis of radiopharmaceuticals.

A method for the production of 111 In from an antimony target irradiated with 600 MeV protons has been developed. Here, a three-stage scheme of indium purification using ion-exchange chromatography is performed. The radiochemical yield is 85%, with a decontamination factor of the target material of no less than 10 9 . The 111 In preparation produced by the present method was used in studies of perturbed angular correlations. Also, a procedure for the production and separation of 117 m Sn/ 119 m Te was developed, which is of particular interest for further studies on designing a generator to produce 119 Sb.

One of the key components of radiopharmaceuticals for targeting imaging and therapy is a stable bifunctional chelating system to attach radionuclides to selective delivery systems. After-effects of radioactive decay can cause the release of a radioactive isotope from its chelation agent. Perturbed angular correlation (PAC) of γ-rays has become a unique technique to study the behavior of complexes formed between a chelating agent and radionuclide in vivo (in real time) over a relevant range of concentrations (10-12 M). In the present work, four radionuclides, 111In, 111mCd, and 152, 154Eu, were investigated with diethylenetriaminepentaacetic acid (DTPA) at different pH values to determine the stability constants of the complexes as well as the effects of post-decay processes, which play a major role in determining the suitability of these complexes for application as radiopharmaceuticals (e.g., in vivo generators). The study provides a convenient parameter for the characterization of radionuclide-chelator systems using the PAC method. PAC is proven to be a suitable tool to study novel chelators and radiopharmaceutical precursors attached to radiometals.

The distribution coefficients for 60 elements on the anion-exchange resin Dowex 1x8 in ammonium acetate medium (0.1–5.0 M) are determined. The values of Kd are presented as a periodic table of the elements. A range of possibilities for separating the elements of this system is proposed.