The successful preclinical efficacy studies prompted a Phase I clinical trial to investigate [161Tb]Tb-SibuDAB. Deeper insight into potential undesired effects on normal tissues and organs remained to be investigated. The aim of this preclinical study was, therefore, to assess and compare the tolerability of [161Tb]Tb-SibuDAB with that of [177Lu]Lu-SibuDAB, [161Tb]Tb-PSMA-I T and [177Lu]Lu-PSMA-I T. The time-dependent tissue distribution profiles of [161Tb]Tb-SibuDAB and [161Tb]Tb-PSMA-I T were assessed in immunocompetent mice for dosimetry estimations. Substructural activity distribution in kidneys was further investigated ex vivo. In Study I, [161Tb]Tb-SibuDAB, [177Lu]Lu-SibuDAB, [161Tb]Tb-PSMA-I T and [177Lu]Lu-PSMA-I T were administered at 30 MBq/mouse while in Study II, additional activities of 15 MBq and 60 MBq [161Tb]Tb-SibuDAB were applied. Blood cell counts were determined on Days 10, 28 and 56 after radioligand injection while blood and bone marrow smears, blood plasma biomarkers and selected organs were investigated at study end on Day 56. Organ uptake and absorbed doses were severalfold higher for SibuDAB than for PSMA-I T and terbium-161 delivered about 40

Ag-111 PAC spectroscopy was applied to explore the rapid dynamics of a small, inorganic probe in water/sucrose solutions with viscosity, xi, from 1 to 121 mPa center dot s at 9 degrees C or 20 degrees C. The measured characteristic timescale does not scale linearly with xi/T, as predicted by the Stokes-Einstein-Debye model for the rotational correlation time, and power-law scaling is also unsatisfactory. In contrast, a model that incorporates local probe-site dynamics on a similar to 400 ps timescale describes the data well. This is the first indication that PAC spectroscopy can resolve both rotational diffusion and picosecond local dynamics via their different xi/T scaling.

The effective electron neutrino mass can be determined by analyzing the end-point region of the ^{163}Ho electron capture spectrum, provided a measurement with high-energy resolution and high statistics using calorimetric techniques. Here, the Electron Capture in ^{163}Ho Collaboration (ECHo) presents an analysis of the most precise ^{163}Ho spectrum currently available, obtained with the ECHo-1k experiment and comprising about 200 million events. A very low background rate of b_{const}=9.1(1.3)×10^{-6} eV/pixel/day was achieved allowing for a reliable analysis of the end-point region. The derived end-point energy Q=2862(4)  eV is in excellent agreement with the one independently determined via Penning-trap mass spectrometry of Q=2863.2(6)  eV [Ch. Schweiger et al., Nat. Phys. 226, 921 (2024)NPAHAX1745-247310.1038/s41567-024-02461-9]. The upper limit of the effective electron neutrino mass is improved by almost a factor of 2 compared to the lowest current value [B. K. Alpert et al., Phys. Rev. Lett. 135, 141801 (2025)PRLTAO0031-900710.1103/s9vl-7n24], reaching m_{ν_{e}}<15  eV/c^{2} (90% credible interval).

We report on high-resolution laser spectroscopy of ^{255}Fm (T_{1/2}=20  h), one of the heaviest nuclides available from reactor breeding. The hyperfine structures in two different atomic ground-state transitions at 398.4 nm and 398.2 nm were probed by in-source laser spectroscopy at the RISIKO mass separator in Mainz, using the perpendicularly illuminated laser ion source and trap (PI-LIST) high-resolution ion source. Experimental results were combined with hyperfine fields from various atomic ab initio calculations, in particular using multiconfiguration Dirac-Hartree-Fock theory, as implemented in grasp18. In this manner, the nuclear magnetic dipole and electric quadrupole moments were derived to be μ=-0.75(5)  μ_{N} and Q_{s}=+5.84(13)  eb, respectively. The magnetic moment indicates occupation of the ν7/2[613] Nilsson orbital, while the large quadrupole moment confirms strong, stable prolate deformation consistent with systematics in the heavy actinides. Comparisons with available expectation values from nuclear theory show good agreement, providing a stringent benchmark for the used theoretical models. These results revise earlier data and establish ^{255}Fm as a reference isotope for future high-resolution studies.

The A ≈ 100 mass region is a cornerstone of contemporary nuclear structure research, defined by a dramatic structural phase transition from spherical to strongly prolate-deformed shapes (β2 ≈ 0.4) that occurs sharply between neutron numbers N = 58 and N = 60. Investigating the odd-odd nuclei in this area, specifically the Nb (Z = 41) and Tc (Z = 43) isotopic chains, is particularly complex due to the demanding requirement of correctly modeling the proton-neutron (p-n) residual interaction and coupling. A historical deficiency of reliable experimental data, coupled with Jπ assignments often based purely on theoretical models, has led to inconsistencies in the literature. To address this, we conducted specialized y-ray and y-conversion electron coincidence spectroscopy experiments utilizing the LOHENGRIN recoil mass spectrometer at the Institut Laue-Langevin. This technique is designed to determine transition multipolarities via internal conversion coefficients, providing the necessary experimental foundation for unambiguous Jπ assignments. Our systematic study, targeting 100Nb, 102Tc, and 104Nb, is aimed at challenging current theoretical understanding of deformation and p-n coupling far from stability. Preliminary analysis of 104Tc data from the initial campaign reveals new candidate y-ray transitions, confirming the need for fundamental revisions to the existing level schemes.

Neutron capture reactions provide essential nuclear physics input for modeling the synthesis of heavy elements in stars. The growing precision of stellar spectroscopy and isotopic measurements in presolar SiC grains now demands cross sections with improved accuracy over the full energy range, and access to unstable nuclei relevant to slow (s-) process branchings and the intermediate (i-) process. This article reviews recent progress in direct neutron capture measurements, focusing on time-of-flight (TOF) experiments at CERN n_TOF and complementary activation techniques. Substantial advances have been achieved for stable s-only and bottleneck isotopes, significantly improving constraints on s-process models. In parallel, the combination of high instantaneous neutron fluxes and advanced detector systems has facilitated first-time neutron capture measurements on several radioactive branching-point nuclei. Feasibility studies, however, reveal current limitations related to sample availability, background conditions, and restricted energy coverage. In this context, the complementarity between TOF and activation emerges as a central strategy. Future developments, including high-flux facilities and novel inverse kinematics experiments in ion storage rings, are expected to extend the boundaries of neutron capture measurements, overcoming current limitations and helping unlock new frontiers in our understanding of stellar nucleosynthesis.

Introduction: Terbium-149 (149Tb) is a promising radionuclide for targeted α therapy that has a non-zero branching ratio (BR) for positron decay. However, its relatively low positron branching fraction and multiple prompt γ emissions may challenge quantitative imaging. This study evaluates the imaging performance and quantitative accuracy of 149Tb using a clinical long axial field-of-view (LAFOV) PET/CT system. Methods: Quantitative accuracy of 149Tb was assessed with a NEMA IEC body phantom, which was filled with about 45MBq 149Tb and a sphere-to-background ration of 10:1. The phantom was scanned for 20min and shorter scan times and lower activities were simulated. Recovery coefficients, coefficient of variation, and lung residual error were evaluated for different reconstruction settings and compared to the EARL standard 2 for 18F. Results: High-quality PET images of 149Tb were obtained, even with a simulated total activity of 4.5MBq. The 20min and full activity scan yielded a mean recovery coefficient RCmean of 0.55, 0.69, 0.73, 0.76, 0.79, and 0.81 for the six phantom spheres. Despite the low count statistics, the coefficient of variation stays mostly below 15%. Relative scatter correction combined with prompt γ modeling provided robust quantification. Conclusion: 149Tb can be imaged using a commercial LAFOV PET/CT with a quantitative accuracy comparable to the EARL standard 2 for 18F. These findings demonstrate the feasibility of PET-based treatment verification and dosimetry for targeted α therapy with 149Tb.

Au-199 has appropriate characteristics to be used for single photon emission computed tomography (SPECT) imaging and/or targeted beta radionuclide therapy. This study focuses on production of non-carrier added Au-199 via radiochemical separation from a Pt target with natural isotopic composition, which has been irradiated in a nuclear reactor. The separation procedure for the separation of Au and Pt using commercially available TBP resin was developed first with stable Au and Pt. Then, the Pt dissolution procedure was optimized. This was followed by test irradiations of Pt targets to assess irradiation yields for Au-199 and to identify radionuclidic impurities. Irradiation yields obtainable by medium-flux and high-flux research reactors were assessed and compared. Finally, the separation procedure was applied to separate Au-199 from irradiated Pt targets. The achieved irradiation yield was up to 485 GBq/g of Pt target. The Au-199 separation efficiency for ∼11 mg Pt targets achieved was 78 % with no radionuclidic impurities, except Au-198 detected. The results indicate that the production of Au-199 activities sufficient for imaging applications is feasible by irradiation of Pt targets with natural isotopic composition in medium-flux reactors. Higher activities for therapeutic applications are more efficiently produced in high-flux reactors.

Radionuclides are widely applied in different medical techniques for diagnosis and treatment. The efficacy of the treatments, as well as the off-target dose minimisation in both diagnosis and treatment depend, among other things, on the decay characteristics of the radionuclide in use: the different particles and radiation emitted, the emission energies and the emission probabilities. These are essential for the calculation of the dose administered to the patient or to medical personnel or caretakers in medical imaging or treatment with radionuclides. In this work we present the Total Absorption Spectroscopy of 152 Tb for its relevance in medicine and whose decay properties were not well enough established.

The low-spin structure of the 206Tl nucleus was studied in the thermal neutron capture reaction 205Tl(n, gamma ) 206Tl at the Institut Laue-Langevin in Grenoble making use of the multidetector HPGe array Fission Product Prompt gamma -ray Spectrometer and gamma gamma -coincidence techniques. The information on discrete structures located below the neutron binding energy in 206Tl was extended: a total number of 99 gamma rays (75 new) were observed and 21 excited states (8 new) were located. The analysis of the angular correlations of gamma rays was used to extract information on transitions multipolarities, which helped with spin-parity assignments for the located levels. The obtained experimental results were compared to shell-model calculations involving one-proton-hole, oneneutron-hole excitations below the 208Pb core. The two-body nucleon-nucleon realistic interactions derived from CD-Bonn free nucleon-nucleon potential were used. Reasonable agreement is obtained for the excitation energies of the states which, according to calculations, have highly fragmented wave functions, particularly in the highenergy region where the density of levels increases. The observed discrepancies are interpreted as a consequence of the large uncertainties in the determination of the off-diagonal matrix elements of the realistic shell-model interaction, which are mainly responsible for the fragmentation of the wave functions.

Terbium-149 is a short-lived α-particle emitter, potentially useful for tumor-targeted therapy. The aim of this study was to investigate terbium-149 in combination with the somatostatin receptor (SSTR) agonist DOTATATE and the SSTR antagonist DOTA-LM3. The radiopeptides were evaluated to compare their therapeutic efficacy in vitro and in vivo. Terbium-149 was produced at ISOLDE/CERN and chemically purified at the Paul Scherrer Institute. Radiolabeling of somatostatin analogues with [149Tb]TbCl3 was performed under standard labeling conditions at pH 4.5. Cell viability (MTT) and survival assays (colony forming) assays were performed after 16–18 h exposure of SSTR-positive AR42J rat pancreatic tumor cells to various activity concentrations of [149Tb]Tb-DOTATATE and [149Tb]Tb-DOTA-LM3. DNA double-strand breaks were determined using immunofluorescence imaging of γ-H2A.X and 53BP1. Therapy studies were performed with AR42J tumor-bearing mice injected with 1 × 5 MBq or 2 × 5 MBq of the respective radiopeptide. The tolerability of up to 40 MBq [149Tb]Tb-DOTATATE or 40 MBq [149Tb]Tb-DOTA-LM3 was assessed with regard to undesired effects to the bone marrow and kidneys in immunocompetent mice without tumors. The radiolabeling of peptides was achieved at molar activities of up to 20 MBq/nmol at ≥ 98

Background and objective: In Boron Neutron Capture Therapy, treatment planning is based on a weighted dose in which dose components are weighted with different biological effectiveness (RBE) factors. The most important one for the tumor dose is the compound dependent biological effectiveness (CBE) factor which weighs the boron dose. This was established for brain tumors from radiobiological experiments and has been extrapolated to the more recent application of BNCT to head and neck cancers. The purpose of this work is to study the validity of this assumption. Methods: Two cell lines, CAL-33 (head and neck squamous cell carcinoma) and A172 (Glioblastoma Multiforme), were irradiated with a very pure thermal-equivalent neutron beam after BPA incubation, and the surviving fraction of cells after irradiation was determined by clonogenicity assays. Results: The Compound Biological Effectiveness of both cell lines is similar, although for head and neck carcinoma, 10% higher values are systematically found. In addition to this, radiobiological coefficients for the different dose components (photon, neutron and boron) of BNCT in both cell lines are provided.

Fission yields are one of the most used observables to describe the fission process. They are also mandatory for nuclear fuel cycle studies or nuclear reactor calculations for instance. In this paper we will show how we can extract independent fission yields and the fission product angular momentum by the combined use of γ-ray measurements and the LOHENGRIN spectrometer. In particular, the importance of nuclear structure data is presented.

Radionuclides are the essential component of radiopharmaceuticals, their production needs to consider pharmaceutical regulations and guidelines, also for clinical research applications. In this paper we reflect on the pharmaceutical regulatory landscape for radionuclide production in Europe, with a focus on Good Manufacturing Practices (GMP). The challenges for novel production pathways and the pathways for non-GMP production of radionuclides are discussed. In particular when radionuclides are used as starting materials, exemptions from GMP requirements are essential for clinical innovation and a common understanding is needed to enable the safe use of novel radionuclides for medical applications without unnecessary regulatory hurdles for the user.

Targeted Alpha Therapy has shown great promise in cancer treatment, sparking significant interest over recent decades. However, its broad adoption has been impeded by the scarcity of alpha-emitters and the complexities related to their use. The availability of these radionuclides is often constrained by the intricate production processes and purification, as well as regulatory and logistical challenges. Moreover, the high cost and technical difficulties associated with handling and applying alpha-emitting radionuclides pose additional barriers to their clinical implementation.This Alpha Atlas provides an in-depth overview of the leading alpha-particle emitting radionuclide candidates for clinical use, focusing on their production processes and supply chains. By mapping the current facilities that produce and supply these radionuclides, this atlas aims to assist researchers, clinicians, and industries in initiating or scaling up the applications of alpha-emitters. The Alpha Atlas aspires to act as a strategic guide, facilitating collaboration and driving forward the integration of these potent therapeutic agents into cancer treatment practices.

A comparative vacuum ultraviolet spectroscopy study conducted at ISOLDE-CERN of the radiative decay of the ^{229m}Th nuclear clock isomer embedded in different host materials is reported. The ratio of the number of radiative decay photons and the number of ^{229m}Th embedded are determined for single crystalline CaF_{2}, MgF_{2}, LiSrAlF_{6}, AlN, and amorphous SiO_{2}. For the latter two materials, no radiative decay signal was observed and an upper limit of the ratio is reported. The radiative decay wavelength was determined in LiSrAlF_{6} and CaF_{2}, reducing its uncertainty by a factor of 2.5 relative to our previous measurement. This value is in agreement with the recently reported improved values from laser excitation.