Production of low and high specific activity 64Cu in a reactor

Evaluation of fine particulate matter on vascular endothelial function in vivo and in vitro

Ambient fine particulate matter (PM_2.5) and high-fat diet (HFD) are linked to the development of atherosclerosis. However, there is still unknown about the PM_2.5-induced atherosclerosis formation on vascular endothelial injury after co-exposed to PM_2.5 and HFD. Thus, the aim of this study was to evaluate the effects of PM_2.5 on atherogenesis in C57BL/6 mice and endothelial cells, as well as the co-exposure effect of PM_2.5 and HFD. In vivo study, C57BL/6 mice exposed to PM_2.5 and fed with standard chow diet (STD) or HFD for 1 month. PM_2.5 could increase vascular stiffness accessed by Doppler ultrasound, and more serious in co-exposure group. PM_2.5 impaired vascular endothelial layer integrity, exfoliated endothelial cells, and inflammatory cells infiltration through H&E staining. PM_2.5 reduced the expression of platelet/endothelial cell adhesion molecule-1 (PECAM-1) in vessel. Moreover, PM_2.5 could induce systemic inflammation detected by Mouse Inflammation Array. In vitro study, PM_2.5 triggered markedly mitochondrial damage by transmission electron microscope (TEM) and flow cytometer. Inflammatory cytokines were significantly increased in PM_2.5-exposed group. The cell viability and migration of endothelial cells were significantly suppressed. In addition, PM_2.5 remarkably declined the expression of vascular endothelial growth factor receptor 2 (VEGFR2) and increased the expression of somatostatin (SST) and its receptor. In conclusion, co-exposure of PM_2.5 and HFD might induce systemic inflammation and endothelial dysfunction in normal mice. Moreover, PM_2.5 could reduce vascular endothelial repair capacity through inhibiting the proliferation and migration of endothelial cells.

IAEA contribution to the development of 64Cu radiopharmaceuticals for theranostic applications

Copper-64 is a very attractive radioisotope with unique nuclear properties that allow using it as both a diagnostic and therapeutic agent, thus providing an almost ideal example of a theranostic radionuclide. A characteristic of Cu-64 stems from the intrinsic biological nature of copper ions that play a fundamental role in a large number of cellular processes. Cu-64 is a radionuclide that reflects the natural biochemical pathways of Cu-64 ions, therefore, can be exploited for the detection and therapy of certain malignancies and metabolic diseases. Beside these applications of Cu-64 ions, this radionuclide can be also used for radiolabelling bifunctional chelators carrying a variety of pharmacophores for targeting different biological substrates. These include peptide-based substrates and immunoconjugates as well as small-molecule bioactive moieties. Fueled by the growing interest of Member States (MS) belonging to the International Atomic Energy Agency (IAEA) community, a dedicated Coordinated Research Project (CRP) was initiated in 2016, which recruited thirteen participating MS from four continents. Research activities and collaborations between the participating countries allowed for collection of an impressive series of results, particularly on the production, preclinical evaluation and, in a few cases, clinical evaluation of various ⁶⁴Cu-radiopharmaceuticals that may have potential impact on future development of the field. Since this CRP was finalized at the beginning of 2020, this short review summarizes outcomes, outputs and results of this project with the purpose to propagate to other MS and to the whole scientific community, some of the most recent achievements on this novel class of theranostic ⁶⁴Cu-pharmaceuticals.

A simple and robust method for radiochemical separation of no-carrier-added 64Cu produced in a research reactor for radiopharmaceutical preparation

Copper-64 is an excellent theranostic radiometal that is gaining renewed attention of the clinical community in the recent times. In order to meet the increasing demand of this radiometal, we have demonstrated the viability of its production via ⁶⁴Zn (n,p) ⁶⁴Cu reaction in a nuclear reactor. A semi-automated radiochemical separation module based on selective extraction of ⁶⁴Cu as dithizonate complex was developed. The maximum available activity at the end of irradiation was ~ 700 MBq. The overall yield of ⁶⁴Cu after the separation process was >85% and it could be obtained with ~12 GBq/μg specific activity, >99.9% radionuclidic purity and >98% radiochemical purity. The separated ⁶⁴Cu could be utilized for preparation of a wide variety of radiopharmaceuticals.

Assessment and estimation of 65Zn production yield via neutron induced reaction on natZnO and natZnONPs

Zinc-65 has been of great interest in medical, biomedical, agricultural, and industrial applications due to its suitable half-life and decay properties. The ⁶⁵Zn was produced via neutron irradiation on natural zinc oxide and natural zinc oxide nanoparticles targets in Tehran Research Reactor (TRR) at a thermal neutron flux of 4.5 × 10¹³ n cm^-2 s^-1 for 30 min. The excitation function of ⁶⁴Zn(n,γ)⁶⁵Zn reaction was calculated via the TALYS-1.8 code. The MCNPX code was used to calculate the thermal neutron distribution. The ⁶⁵Zn theoretical production yield was estimated using calculated cross sections and the calculated thermal neutron distribution. The obtained experimental data and simulated value of production yield for ⁶⁵Zn were in reasonable agreement.

64Cu, a powerful positron emitter for immunoimaging and theranostic: Production via natZnO and natZnO-NPs

⁶⁴Cu is one of the most beneficial radionuclide that can be used as a theranostic agent in Positron Emission Tomography (PET) imaging. In this current work, ⁶⁴Cu was produced with zinc oxide nanoparticles (^natZnONPs) and zinc oxide powder (^natZnO) via the ⁶⁴Zn(n,p)⁶⁴Cu reaction in Tehran Research Reactor (TRR) and the activity values were compared with each other. The theoretical activity of ⁶⁴Cu also was calculated with MCNPX-2.6 and the cross sections of this reaction were calculated by using TALYS-1.8, EMPIRE-3.2.2 and ALICE/ASH nuclear codes and were compared with experimental values. Transmission Electronic Microscopy (TEM), Scanning Electronic Microscopy (SEM) and X-Ray Diffraction (XRD) analysis were used for samples characterizations. From these results, it's concluded that ⁶⁴Cu activity value with nanoscale target was achieved more than the bulk state target and had a good adaptation with the MCNPX result.

Production, separation and supply prospects of 67Cu with the development of fast neutron sources and photonuclear technology

Experimental investigations have been carried out on the production of a promising therapeutic radionuclide 67Cu via the 67Zn(n,p)67Cu, 68Zn(n,x)67Cu, and 68Zn(γ,p)67Cu reaction routes. Natural zinc metal foils were irradiated with 14.1 MeV neutrons and bremsstrahlung of end-point energy 15 MeV. Radioactivity levels of 67Cu and other radioisotopes co-produced were determined by the quantification of photo-peaks by off-line γ-ray spectrometry. No carrier added 67Cu was separated from the irradiated zinc by solvent extraction. Yields >90% and high levels of radionuclidic purity were achieved. These studies indicate that the growth and development of intense fast neutron sources and photonuclear technology, will possibly aid in the sustained supply of 67Cu.

Theoretical estimation of 64Cu production with neutrons emitted during 18F production with a 30MeV medical cyclotron

PURPOSE

This work presents the theoretical estimation of a combined production of ¹⁸F and ⁶⁴Cu isotopes for PET applications. ⁶⁴Cu production is induced in a secondary target by neutrons emitted during a routine ¹⁸F production with a 30MeV cyclotron: protons are used to produce ¹⁸F by means of the ¹⁸O(p,n)¹⁸F reaction on a [¹⁸O]-H₂O target (primary target) and the emitted neutrons are used to produce ⁶⁴Cu by means of the ⁶⁴Zn(n,p)⁶⁴Cu reaction on enriched zinc target (secondary target).

METHODS

Monte Carlo simulations were carried out using Monte Carlo N Particle eXtended (MCNPX) code to evaluate flux and energy spectra of neutrons produced in the primary (Be+[¹⁸O]-H₂O) target by protons and the attenuation of neutron flux in the secondary target. ⁶⁴Cu yield was estimated using an analytical approach based on both TENDL-2015 data library and experimental data selected from EXFOR database.

RESULTS

Theoretical evaluations indicate that about 3.8 MBq/μA of ⁶⁴Cu can be obtained as a secondary, 'side' production with a 30MeV cyclotron, for 2h of irradiation of a proper designed zinc target. Irradiating for 2h with a proton current of 120 μA, a yield of about 457 MBq is expected. Moreover, the most relevant contaminants result to be ^63,65Zn, which can be chemically separated from ⁶⁴Cu contrarily to what happens with proton irradiation of an enriched ⁶⁴Ni target, which provides ⁶⁴Cu mixed to other copper isotopes as contaminants.

CONCLUSIONS

The theoretical study discussed in this paper evaluates the potential of the combined production of ¹⁸F and ⁶⁴Cu for medical purposes, irradiating a properly designed target with 30MeV protons. Interesting yields of ⁶⁴Cu are obtainable and the estimation of contaminants in the irradiated zinc target is discussed.

64CuCl2 produced by direct neutron activation route as a cost-effective probe for cancer imaging: the journey has begun

Neutron activated ⁶⁴CuCl₂ is a cost-effective PET probe for non-invasive visualization of various types of cancers.

Development of radiochemistry in Pakistan – 1960 to 2010

With the inception of Pakistan Atomic Energy Commission (PAEC) in 1956, peaceful uses of atomic energy commenced for the benefit of scientific community as well as masses of Pakistan. Radiochemistry played a vital role right from the beginning. The research and development in this field accelerated soon after the criticality of the first research reactor named as Pakistan Research Reactor (PARR- 1) at the Pakistan Institute of Nuclear Science and Technology (PINSTECH), Islamabad. The first radioisotope produced at PARR-1 for application in nuclear medicine was 131I. Later on, many other radioisotopes were prepared and radiopharmaceuticals were synthesised for their use in industry and hospitals. Besides providing pure radioactive tracers for nuclear medicine, radiochemistry also enhanced the detection limit of impurities at all stages of nuclear fuel cycle for power generation. In 1983, research in the field of nuclear data measurement began. The main aim was to identify suitable conditions for the production of radionuclides for cancer diagnostics, treatment and therapy. With the establishment of a second research reactor (PARR-2) at PINSTECH, research in neutron activation analysis, radioisotope production and separation studies gained more momentum and many research articles were published. Solvent extraction, adsorption and ion-exchange were the main routes of separation in those studies. Separation of heavy metals and treatment of waste generated in a nuclear power plant are other important aspects related to environmental restoration and nuclear waste management, where radiochemistry is required. In future, work in radiochemistry will be continued on similar lines to develop novel radiopharmaceuticals, identify indigenous schemes for nuclear waste management and work out intelligent procedures for material characterization for benefit to mankind, especially the people of Pakistan.

Production of medical radioisotopes with linear accelerators

In this study, we discuss producing radioisotopes using linear electron accelerators and address production and separation issues of photoneutron (γ,n) and photoproton (γ,p) reactions. While (γ,n) reactions typically result in greater yields, separating product nuclides from the target is challenging since the chemical properties of both are the same. Yields of (γ,p) reactions are typically lower than (γ,n) ones, however they have the advantage that target and product nuclides belong to different chemical species so their separation is often not such an intricate problem. In this paper we consider two examples, (100)Mo(γ,n)(99)Mo and (68)Zn(γ,p)(67)Cu, of photonuclear reactions. Monte-Carlo simulations of the yields are benchmarked with experimental data obtained at the Idaho Accelerator Center using a 44MeV linear electron accelerator. We propose using a kinematic recoil method for photoneutron production. This technique requires (100)Mo target material to be in the form of nanoparticles coated with a catcher material. During irradiation, (99)Mo atoms recoil and get trapped in the coating layer. After irradiation, the coating is dissolved and (99)Mo is collected. At the same time, (100)Mo nanoparticles can be reused. For the photoproduction method, (67)Cu can be separated from the target nuclides, (68)Zn, using standard exchange chromatography methods. Monte-Carlo simulations were performed and the (99)Mo activity was predicted to be about 7MBq/(g(⁎)kW(⁎)h) while (67)Cu activity was predicted to be about 1MBq/(g(⁎)kW(⁎)h). Experimental data confirm the predicted activity for both cases which proves that photonuclear reactions can be used to produce radioisotopes. Lists of medical isotopes which might be obtained using photonuclear reactions have been compiled and are included as well.