First preclinical SPECT/CT imaging and biodistribution of [Er]ErCl and [Er]Er-PSMA-617.

Background: Er (t = 10.4 h, E = 47.1 keV (59.

Development of thiacrown ligands for encapsulation of mercury-197m/g into radiopharmaceuticals.

The theranostic pair mercury-197m and mercury-197g (Hg, = 23.8 h/64.14 h), through their γ rays and Meitner-Auger electron emissions, have potential use as constituents in radiopharmaceuticals to treat small metastatic tumours.

Preclinical Evaluation of Ac as a Theranostic Agent: Imaging, Dosimetry, and Therapy.

Ac (t = 29.37 h) has been proposed as a theranostic radioisotope leveraging both its diagnostic γ-emissions and therapeutic α-emissions. Ac emits 158 and 230 keV γ-photons ideal for quantitative SPECT imaging and acts as an in vivo generator of 4 high-energy α-particles.

Quantitative SPECT imaging of Tb and Tb for preclinical theranostic radiopharmaceutical development.

Background: Element-equivalent matched theranostic pairs facilitate quantitative in vivo imaging to establish pharmacokinetics and dosimetry estimates in the development of preclinical radiopharmaceuticals. Terbium radionuclides have significant potential as matched theranostic pairs for multipurpose applications in nuclear medicine. In particular, Tb (t = 5.

Chemistry of Antimony in Radiopharmaceutical Development: Unlocking the Theranostic Potential of Sb Isotopes.

Antimony-119 (Sb) holds promise for radiopharmaceutical therapy (RPT), emitting short-range Auger and conversion electrons that can deliver cytotoxic radiation on a cellular level. While it has high promise theoretically, experimental validation is necessary for Sb in vivo applications. Current Sb production and separation methods face robustness and compatibility challenges in radiopharmaceutical synthesis.

Capturing Mercury-197m/g for Auger Electron Therapy and Cancer Theranostic with Sulfur-Containing Cyclen-Based Macrocycles.

The interest in mercury radioisotopes, Hg ( = 23.8 h) and Hg ( = 64.14 h), has recently been reignited by the dual diagnostic and therapeutic nature of their nuclear decays.

quantitative SPECT imaging of actinium-226: feasibility and proof-of-concept.

.Ac radiopharmaceuticals have tremendous potential for targeted alpha therapy, however,Ac (= 9.9 d) lacks direct gamma emissions forimaging.

Preclinical evaluation of MC1R targeting theranostic pair [Tb]Tb-crown-αMSH and [Tb]Tb-crown-αMSH.

Background: Targeted radionuclide therapy is established as a highly effective strategy for the treatment of metastatic tumors; however, the co-development of suitable imaging companions to therapy remains significant challenge. Theranostic isotopes of terbium (Tb, Tb, Tb, Tb) have the potential to provide chemically identical radionuclidic pairs, which collectively encompass all modes of nuclear decay relevant to nuclear medicine. Herein, we report the first radiochemistry and preclinical studies involving Tb- and Tb-labeled crown-αMSH, a small peptide-based bioconjugate suitable for targeting melanoma.

Exploration of commercial cyclen-based chelators for mercury-197 m/g incorporation into theranostic radiopharmaceuticals.

A comprehensive investigation of the Hg coordination chemistry and Hg radiolabeling capabilities of cyclen-based commercial chelators, namely, DOTA and DOTAM (aka TCMC), along with their bifunctional counterparts, -SCN-Bn-DOTA and -SCN-Bn-TCMC, was conducted to assess the suitability of these frameworks as bifunctional chelators for the Hg theranostic pair. Radiolabeling studies revealed that TCMC and DOTA exhibited low radiochemical yields (0%-6%), even when subjected to harsh conditions (80°C) and high ligand concentrations (10 M). In contrast, -SCN-Bn-TCMC and -SCN-Bn-DOTA demonstrated significantly higher Hg radiochemical yields (100% ± 0.

High Separation Factor, High Molar Activity, and Inexpensive Purification Method for the Production of Pure Er.

: Auger electron-emitting radionuclides with low (0.001-1 keV) energy, short-range (2-500 nm), and high linear energy transfer (4-26 keV/μm) can play an important role in the targeted radionuclide therapy (TRT) of cancer. Er is a pure Auger electron-emitting radionuclide, making it a useful tool for the fundamental studies of the biological effects of Auger electrons.

Implementing Ac-225 labelled radiopharmaceuticals: practical considerations and (pre-)clinical perspectives.

Background: In the past years, there has been a notable increase in interest regarding targeted alpha therapy using Ac-225, driven by the observed promising clinical anti-tumor effects. As the production and technology has advanced, the availability of Ac-225 is expected to increase in the near future, making the treatment available to patients worldwide.

Main Body: Ac-225 can be labelled to different biological vectors, whereby the success of developing a radiopharmaceutical depends heavily on the labelling conditions, purity of the radionuclide source, chelator, and type of quenchers used to avoid radiolysis.

The new annotated checklist of the wild bees of Europe (Hymenoptera: Anthophila).

At a time when nature conservation has become essential to ensure the long-term sustainability of our environment, it is widely acknowledged that conservation actions must be implemented within a solid taxonomic framework. In preparation for the upcoming update of the IUCN Red List, we here update the European checklist of the wild bees (sensu the IUCN geographical framework). The original checklist, published in 2014, was revised for the first time in 2017.

The relationship between structural changes in paraspinal muscles and intervertebral disc and facet joint degeneration in the lumbar spine of rats.

Background: Degenerative spine disease is one of the largest causes of disability worldwide and has a multifactorial aetiology. Determining the leading causes of this multifactorial disease could help create new treatment approaches.

Purpose: Study the impact of degenerative changes in the paraspinal muscles caused by local (prolonged compression) or systemic (high-fat diet) factors on the structure of the intervertebral discs (IVDs) and facet joints of the lumbar spine in rats.

Rearmed Bifunctional Chelating Ligand for Ac/Tb Precision-Guided Theranostic Radiopharmaceuticals─HnoneunpaX.

Superior bifunctional chelating ligands, which can sequester both α-emitting radionuclides (Ac, Bi) and their diagnostic companions (Tb, In), remain a formidable challenge to translating targeted alpha therapy, with complementary diagnostic imaging, to the clinic. HnoneupaX, a chelating ligand with an unusual diametrically opposed arrangement of pendant donor groups, has been developed to this end. HnoneunpaX preferentially complexes Ln and An ions, forming thermodynamically stable (pLa = 17.

Separation of Sc/Sc Nuclear Isomers Based on After-Effects.

Sc presents a particular interest for application in nuclear medicine for positron emission tomography (PET) due to its favorable nuclear decay properties ( = 3.97 h, = 1.47 MeV, branching ratio 94.

Marshalling the Potential of Auger Electron Radiopharmaceutical Therapy.

Auger electron (AE) radiopharmaceutical therapy (RPT) may have the same therapeutic efficacy as α-particles for oncologic small disease, with lower risks of normal-tissue toxicity. The seeds of using AE emitters for RPT were planted several decades ago. Much knowledge has been gathered about the potency of the biologic effects caused by the intense shower of these low-energy AEs.

Production and radiochemistry of antimony-120m: Efforts toward Auger electron therapy with Sb.

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.

Preclinical Evaluation of [Tb]Tb-Crown-TATE-A Novel SPECT Imaging Theranostic Agent Targeting Neuroendocrine Tumours.

Terbium radioisotopes (Tb, Tb, Tb, Tb) offer a unique class of radionuclides which encompass all four medicinally relevant nuclear decay modalities (α, , γ, /e), and show high potential for the development of element-matched theranostic radiopharmaceuticals. The goal of this study was to design, synthesise, and evaluate the suitability of crown-TATE as a new peptide-conjugate for radiolabelling of [Tb]Tb and [Tb]Tb, and to assess the imaging and pharmacokinetic properties of each radiotracer in tumour-bearing mice. [Tb]Tb-crown-TATE and [Tb]Tb-crown-TATE were prepared efficiently under mild conditions, and exhibited excellent stability in human serum (>99.

A new bee species of the genus Dasypoda Latreille (Hymenoptera, Apoidea) from Northwest Africa with comparative remarks on the subgenus Microdasypoda Michez.

North Africa, with its vast array of ecosystems and reliefs, constitutes a remarkable place to explore and describe the diversity of wild bees. In this paper, a new bee species of the genus Dasypoda Latreille (Hymenoptera, Apoidea, Melittidae), D. schwarzi Radchenko et Michez sp.

Production of Co-58m in a siphon-style liquid target on a medical cyclotron.

We present the production of Co on a small, 13 MeV medical cyclotron utilizing a siphon style liquid target system. Different concentrated iron(III)-nitrate solutions of natural isotopic distribution were irradiated at varying initial pressures and subsequently separated by solid phase extraction chromatography. The radio cobalt (Co and Co) was successfully produced with saturation activities of (0.

Engineering a modular Ti/Sc generator: eluate evaluation in preclinical models and estimation of human radiation dosimetry.

Background: Sc/Sc is an attractive theranostic pair for targeted in vivo positron emission tomographic (PET) imaging and beta-particle treatment of cancer. The Ti/Sc generator allows daily onsite production of this diagnostic isotope, which may provide an attractive alternative for PET facilities that lack in-house irradiation capabilities. Early animal and patient studies have demonstrated the utility of Sc.

Cyclotron production of Pd using a liquid target.

Introduction: In this work, we present the first feasibility study on the production of the medically important radionuclide Pd via the Rh(p,n)Pd reaction by cyclotron irradiation of a liquid target. Using a liquid target removes the time consuming and complex dissolution process of rhodium post-irradiation due to its chemically inactive nature and thereby will improve the accessibility of this radioisotope.

Methods: Liquid targets made from Rh(NO)·×HO salt dissolved in de-ionized water were irradiated using a 12 MeV beam at the TR13 cyclotron at TRIUMF, Vancouver.

Selective Chelation of the Exotic Meitner-Auger Emitter Mercury-197 m/g with Sulfur-Rich Macrocyclic Ligands: Towards the Future of Theranostic Radiopharmaceuticals.

Mercury-197 m/g are a promising pair of radioactive isomers for incorporation into a theranostic as they can be used as a diagnostic agent using SPECT imaging and a therapeutic via Meitner-Auger electron emissions. However, the current absence of ligands able to stably coordinate Hg to a tumour-targeting vector precludes their use in vivo. To address this, we report herein a series of sulfur-rich chelators capable of incorporating Hg into a radiopharmaceutical.

Comparative Study of a Decadentate Acyclic Chelate, HOPO-O, and Its Octadentate Analogue, HOPO-O, for Radiopharmaceutical Applications.

Radiolanthanides and actinides are aptly suited for the diagnosis and treatment of cancer via nuclear medicine because they possess unique chemical and physical properties (e.g., radioactive decay emissions).

Determination of distribution coefficients of mercury and gold on selected extraction chromatographic resins - towards an improved separation method of mercury-197 from proton-irradiated gold targets.

Radioisotope mercury-197g (Hg, half-life: 64.14 h) along with its metastable isomer (Hg, half-life: 23.8 h) are potential candidates for targeted Meitner-Auger electron therapy due to their suitable decay properties.