Cyclotron production of manganese-52: a promising avenue for multimodal PET/MRI imaging.

Background: The integration of positron emission tomography (PET) and magnetic resonance imaging (MRI) holds promise for advancing diagnostic imaging capabilities. The METRICS project aims to develop cyclotron-driven production of Mn for PET/MRI imaging.

Results: Using the Cr(p,n)Mn reaction, we designed chromium metal targets via Spark Plasma Sintering and developed a separation procedure for isolating Mn.

Bifunctional octadentate pseudopeptides as Zirconium-89 chelators for immuno-PET applications.

Background: Positron emission tomography (PET) is a highly sensitive method that provides fine resolution images, useful in the field of clinical diagnostics. In this context, Zirconium-89 (Zr)-based imaging agents have represented a great challenge in molecular imaging with immuno-PET, which employs antibodies (mAbs) as biological vectors. Indeed, immuno-PET requires radionuclides that can be attached to the mAb to provide stable in vivo conjugates, and for this purpose, the radioactive element should have a decay half-life compatible with the time needed for the biodistribution of the immunoglobulin.

Development and Evaluation of the Magnetic Properties of a New Manganese (II) Complex: A Potential MRI Contrast Agent.

Magnetic resonance imaging (MRI) is a non-invasive powerful modern clinical technique that is extensively used for the high-resolution imaging of soft tissues. To obtain high-definition pictures of tissues or of the whole organism this technique is enhanced by the use of contrast agents. Gadolinium-based contrast agents have an excellent safety profile.

Highlight selection of radiochemistry and radiopharmacy developments by editorial board.

Background: The Editorial Board of EJNMMI Radiopharmacy and Chemistry releases a biannual highlight commentary to update the readership on trends in the field of radiopharmaceutical development.

Main Body: This commentary of highlights has resulted in 21 different topics selected by each coauthoring Editorial Board member addressing a variety of aspects ranging from novel radiochemistry to first in man application of novel radiopharmaceuticals.

Conclusion: Trends in radiochemistry and radiopharmacy are highlighted demonstrating the progress in the research field in various topics including new PET-labelling methods, FAPI-tracers and imaging, and radionuclide therapy being the scope of EJNMMI Radiopharmacy and Chemistry.

Target manufacturing by Spark Plasma Sintering for efficient Zr production.

Zirconium-89 (Zr) is an emerging radionuclide for positron emission tomography (PET), with nuclear properties suitable for imaging slow biological processes in cellular targets. The Y(p,n)Zr nuclear reaction is commonly exploited as the main production route with medical cyclotrons accelerating low-energy (< 20 MeV) and low-current (< 100 μA) proton beams. Usually, natural yttrium solid targets manufactured by different methods, including yttrium electrodeposition, yttrium sputtering, compressed yttrium powders, and foils, were employed.

A Universal Cassette-Based System for the Dissolution of Solid Targets.

Cyclotron-based radionuclides production by using solid targets has become important in the last years due to the growing demand of radiometals, e.g., Ga, Zr, Sc, and Mn.

Highlight selection of radiochemistry and radiopharmacy developments by editorial board.

Background: The Editorial Board of EJNMMI Radiopharmacy and Chemistry releases a biyearly highlight commentary to update the readership on trends in the field of radiopharmaceutical development.

Results: This commentary of highlights has resulted in 21 different topics selected by each member of the Editorial Board addressing a variety of aspects ranging from novel radiochemistry to first in man application of novel radiopharmaceuticals. Also the first contribution in relation to MRI-agents is included.

Coalescence of Macroscopic Flux Ropes at the Subsolar Magnetopause: Magnetospheric Multiscale Observations.

We report unambiguous in situ observation of the coalescence of macroscopic flux ropes by the magnetospheric multiscale (MMS) mission. Two coalescing flux ropes with sizes of ∼1  R_{E} were identified at the subsolar magnetopause by the occurrence of an asymmetric quadrupolar signature in the normal component of the magnetic field measured by the MMS spacecraft. An electron diffusion region (EDR) with a width of four local electron inertial lengths was embedded within the merging current sheet.

Rhenium(V) and technetium(V) nitrido complexes with mixed tridentate π-donor and monodentate π-acceptor ligands.

Mixed-ligand [M(N)(SNS)(PPh(3))] complexes (M = Tc, Re) (1, 2) were prepared by reaction of the precursor [M(N)Cl(2)(PPh(3))(2)] with ligand 2,2'-dimercaptodiethylamine [H(2)SNS = NH(CH(2)CH(2)SH)(2)] in refluxing dichloromethane/ethanol mixtures. In these compounds, 2,2'-dimercaptodiethylamine acts as a dianionic tridentate chelating ligand bound to the [M≡N](2+) group through the two π-donor deprotonated sulfur atoms and the protonated amine nitrogen atom. Triphenylphosphine completes the coordination sphere, acting as a monodentate ligand.

Labeling of fatty acid ligands with the strong electrophilic metal fragment [99mTc(N)(PNP)]2+ (PNP=diphosphane ligand).

The electrophilic metal fragment [(99m)Tc(N)(PNP)](2+) (PNP=diphosphane ligand) has been employed for the labeling of fatty acid chains of different lengths. To provide a site-specific group for the attachment of the metallic moiety, the fatty acid derivatives were functionalized by appending a bis-mercapto or, alternatively, a dithiocarbamato pi-donor chelating systems to one terminus of the carbon chain to yield both dianionic and monoanionic bifunctional ligands (L). The resulting complexes, [(99m)Tc(N)(PNP)(L)] (0/+), exhibited the usual asymmetrical structure in which a Tc(triple bond)N group was surrounded by two different bidentate chelating ligands.

From symmetrical to asymmetrical nitrido phosphino-thiol complexes: a new class of neutral mixed-ligand (99m)Tc compounds as potential brain imaging agents.

A general procedure is presented for the preparation of a new class of nitrido asymmetrical Tc-99m complexes containing two different bidentate ligands bound to the same [Tc(N)]2+ core that could be used to design either essential or target specific imaging agents. This procedure is based on the chemical properties of a new monosubstituted [Tc(N)(R2PS)Cl(PPh3)] species composed of a TcN multiple bond and an ancillary phosphine thiol ligand (R2PSH). This intermediate readily reacts with bidentate mononegative ligands (S--Y) containing soft pi-donor coordinating atoms to give neutral pentacoordinate asymmetrical complexes of the type [Tc(N)(R2PS)(S--Y)].

Synthesis, characterization, and biological evaluation of neutral nitrido technetium(V) mixed ligand complexes containing dithiolates and aminodiphosphines. A novel system for linking technetium to biomolecules.

A new biomolecule labeling method that utilizes the [(99m)Tc(N)(PNP)](2+) metal fragment is presented. Thus, a series of nitrido mixed-ligand M(V) complexes (M = (99m)Tc, (99g)Tc, Re), [M(N)(Ln)(PNP)], where Ln is the dianionic form of a dithiolate or substituted-dithiolate ligand and PNP is an aminodiphosphine, is described. (99m)Tc complexes can be prepared using either a two-step or a three-step procedure starting from generator-eluted pertechnetate through a prereduced mixture of [(99m)Tc(N)]-containing species, followed by sequential or contemporary addition of the relevant dithiolate and aminodiphosphine.

Rapid potentiometric determination of cholinesterases in plasma and red cells: application to eptastigmine monitoring.

Eptastigmine (MF 201) is a new physostigmine derivative with potent inhibitory activity on cholinesterases. Here we present a new potentiometric cholinesterase activity assay suitable for MF 201 monitoring. The analysis is performed on a differential pH system and has the following characteristics: (a) within-run precision: C.

Whole blood L-lactate assay by a new differential pH method: application to metabolic investigations.

We propose a new quantitative method for L-lactate assay in whole blood, based on the measurement of pH variation caused by specific and irreversible oxidation of L-lactate to pyruvate in the presence of an electron acceptor (hexacyanoferrate) and of the enzyme cytochrome b2 (EC 1.1.2.