¹³⁵ La has favorable nuclear and chemical properties for Auger-based targeted internal radiotherapy. Here we present detailed investigations of the production, emissions, and dosimetry related to ¹³⁵ La therapy. ¹³⁵ La was produced by 16.5 MeV proton irradiation of metallic ^nat Ba on a medical cyclotron, and was isolated and purified by trap-and-release on weak cation-exchange resin. The average production rate was 407 ± 19 MBq µ A ⁻¹ (saturation activity), and the radionuclidic purity was 98% at 20 h post irradiation. Chemical separation recovered > 98 % of the ¹³⁵ La with an effective molar activity of 70 ± 20 GBq µ mol ⁻¹ . To better assess cellular and organ dosimetry of this nuclide, we have calculated the x-ray and Auger emission spectra using a Monte Carlo model accounting for effects of multiple vacancies during the Auger cascade. The generated Auger spectrum was used to calculate cellular S -factors. ¹³⁵ La was produced with high specific activity, reactivity, radionuclidic purity, and yield. The emission spectrum and the dosimetry are favorable for internal radionuclide therapy.

⁶⁴Cu radiolabelled nanodiscs based on the 11 α-helix MSP1E3D1 protein and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine lipids were, for the first time, followed in vivo by positron emission tomography for evaluating the biodistribution of nanodiscs. A cancer tumor bearing mouse model was used for the investigations, and it was found that the approximately 13 nm nanodiscs, due to their size, permeate deeply into cancer tissue. This makes them promising candidates for both drug delivery purposes and as advanced imaging agents. For the radiolabelling, a simple approach for ⁶⁴Cu radiolabelling of proteins via a chelating agent, DOTA, was developed. The reaction was performed at sufficiently mild conditions to be compatible with labelling of the protein part of a lipid-protein particle while fully conserving the particle structure including the amphipathic protein fold.

Background: In order to support the ongoing research across Europe to facilitate access to novel radionuclides, the PRISMAP consortium (European medical radionuclides programme) was established to offer the broadest catalog of non-conventional radionuclides for medical and translational research. The aim of this article is to introduce readers with current status of novel radionuclides in Europe. Main body: A consortium questionnaire was disseminated through the PRISMAP consortium and user community, professional associations and preclinical/clinical end users in Europe and the current status of clinical end-users in nuclear medicine were identified. A total of 40 preclinical/clinical users institutions took part in the survey. Clinical end users currently use the following radionuclides in their studies: ¹⁷⁷Lu, ⁶⁸ Ga, ¹¹¹In, ⁹⁰Y, other alpha emitters, ²²⁵Ac, ⁶⁴Cu and Terbium isotopes. Radionuclides that would be of interest for users within the next 2–5 years are ⁶⁴Cu, Terbium radionuclide “family” and alpha emitters, such as ²²⁵Ac. Conclusions: Thanks to a questionnaire distributed by the PRISMAP consortium, the current status and needs of clinical end-users in nuclear medicine were identified.

In the field of medical and scientific research, radionuclides are used to investigate various physiological and pathological processes. PRISMAP - the European medical radionuclide programme was created to bring together production facilities including intense neutron sources, an isotope mass separation facility, high-power accelerators, biomedical research institutes, and hospitals to support medical research. The aim of this article is to introduce readers with the current status of innovative radionuclides in Europe. A survey was created targeting the latest trends mainly focused on the demand, the production and the distribution of non-routinely used medical radionuclides for use in research, and for pre-clinical and clinical trials. This survey has been disseminated through the PRISMAP community. 16 of 104 respondents were working in the field of radionuclide production. The data found common aspects from all producer-facility respondents: the biggest challenge for the producers is the availability of target materials, which goes hand-in-hand with their purity/enrichment grade. The results show that there are sufficient national or international distribution routes and methods established, although having reported challenges due to legislation constraints, especially for novel radionuclides. Thanks to a questionnaire distributed by the PRISMAP consortium, the current status in radionuclides production was identified. Understanding the current status of radionuclide production is essential for assessing the continent’s capabilities and addressing the burgeoning demands for cutting-edge medical radionuclides.

Knowledge about zinc availability from human diets is limited due to methodological difficulties. Recently developed stable isotope techniques for estimating dietary zinc absorption were compared with radioisotope techniques in five men and three women. Stable and radioactive zinc isotopes were simultaneously administered. Fecal excretion of the isotopes as well as whole-body retention of the radioactive zinc isotope was monitored. Concentration of stable zinc isotope label in fecal samples was determined by inductively coupled plasma mass spectrometry by fully quantitative measurements and from inductively coupled plasma mass spectrometry isotope ratios combined with analysis of total zinc content using atomic absorption spectrometry. Zinc absorption estimated from whole-body retention was 27 +/- 6% (mean +/- SD), estimated zinc absorption obtained by fecal monitoring of radioisotope was 26 +/- 9%, and the two stable zinc measurements resulted in values of 29 +/- 12 and 33 +/- 12%, respectively. There was no significant difference in zinc absorption estimated from whole-body retention and with the fecal monitoring methods. Recovered stable zinc isotope label was significantly lower than recovered radioisotope. For individual fecal samples, systematic differences of 16% and 12%, respectively (P < 0.05), between the radioisotope recovery and the recovery of stable isotopes with the two methods for measurement was observed. The stable zinc isotope technique for measurement of zinc absorption resulted in mean results similar to those of the radioisotope technique, but with a larger variation in the measurements.

Selectivity for monovalent metal ions is an important facet of the function of the metalloregulatory protein CueR. ¹¹¹Ag perturbed angular correlation of γ‐rays (PAC) spectroscopy probes the metal site structure and the relaxation accompanying the instantaneous change from Ag^I to Cd^II upon ¹¹¹Ag radioactive decay. That is, a change from Ag^I, which activates transcription, to Cd^II, which does not. In the frozen state (−196 °C) two nuclear quadrupole interactions (NQIs) are observed; one (NQI₁) agrees well with two coordinating thiolates and an additional longer contact to the S77 backbone carbonyl, and the other (NQI₂) reflects that Cd^II has attracted additional ligand(s). At 1 °C only NQI₂ is observed, demonstrating that relaxation to this structure occurs within ≈10 ns of the decay of ¹¹¹Ag. Thus, transformation from Ag^I to Cd^II rapidly disrupts the functional linear bis(thiolato)Ag^I metal site structure. This inherent metal site flexibility may be central to CueR function, leading to remodelling into a non‐functional structure upon binding of non‐cognate metal ions. In a broader perspective, ¹¹¹Ag PAC spectroscopy may be applied to probe the flexibility of protein metal sites.