Volume 112, Issue 9

Radioactive radium (Ra) mainly comes from the mining and milling of uranium and other metal or non-metal mines, phosphate production and fertilizer use, production of oil and gas, coal combustion, wastewater treatment, and various wastes from the above activities, which is ubiquitous in the environment. Phytoremediation is a green and cheap remediation technology for metal/radionuclide-contaminated sites. Radium is often of particular interest and there are many literatures on parameters of Ra concentration in plants and transfer factors from soil to plant from a radiological impact assessment point of view. However, review articles on phytoremediation of Ra-polluted soil are relatively few. This review focused on radium-polluted soil phytoremediation, involving two main strategies of phytoextraction and phytostabilization, which covered the potential (hyper)accumulators for Ra, characteristics of Ra uptake from soil by plants, influencing factors, and phytostabilization application. In future research works, more attention should be paid to the deep insights and mechanism researches of Ra uptake/immobilization by plants. This review will deepen the understanding of the relationship of radium-soil-plants, and to enhance the potential application of phytoremediation as an alternative treatment technology for remediation of Ra-polluted soil site.

An important challenge in utilizing particle morphology in nuclear forensic or fuel fabrication applications is understanding why differences in morphologies are observed following varying processing conditions. This is often due to competition and interplay between thermodynamic and kinetic influences. To that end, some of the kinetic influences in the uranyl peroxide precipitation reaction were evaluated and compared to thermodynamic influences studied previously. Metastudtite (UO 2 O 2 ·2H 2 O) was synthesized from solutions of uranyl nitrate or chloride, and the reaction time was varied from 100 s to 230 min enabling an evaluation of kinetic and thermodynamic influences. The metastudtite was then calcined to U 3 O 8 , and all materials were analyzed by powder X-ray diffraction ( p -XRD) and scanning electron microscopy (SEM). Analysis by p -XRD confirmed the sample purity of metastudtite and U 3 O 8 . SEM images were analyzed using the Morphological Analysis for Materials (MAMA) software to measure the size and shape of the nanoparticles for a statistical comparison between materials. Metastudtite produced at shorter reaction times exhibited a kinetically controlled shape by forming smaller and rounder particles than metastudtite produced at longer reaction times. Metastudtite produced at the longer reaction times exhibited differences between the uranyl nitrate and uranyl chloride routes with the nitrate exhibiting a more angular and faceted morphology than the chloride. Overall, the control of the supersaturation ratio ( S ) played a significant role in determining the morphology of the metastudtite. Morphological differences between the U 3 O 8 confirmed the role of nanoparticle agglomeration in forming larger sintered particles. The results help demonstrate the importance of understanding particle formation mechanisms in the long-term development of morphology in nuclear forensics or in developing advanced fuels with specific characteristics.

In this study, the composite materials based on the incorporation of diatomite of graphene oxide (GO)/reduced graphene oxide (rGO/diatomite) were developed and characterized by different techniques (SEM, XRD, FTIR and BET). Developed composites were used for the first time in the removal of uranium ions from aqueous solutions. In adsorption studies, parameters affecting the adsorption efficiency such as solution pH, temperature, contact time and initial U(VI) concentration were investigated using full factorial experimental design (FFED). ANOVA (analysis of variance) analysis within the 95 % confidence interval of the model applied to control the compatibility of the model and the experimental findings was examined. Langmuir, Freundlich and Temkin isotherms were used to determine the adsorption model and related parameters were calculated. In addition, adsorption thermodynamic parameters such as enthalpy, Gibbs free energy change and entropy were calculated. The uranium removal behaviour on GO/diatomite and rGO/diatomite was better characterized by the pseudo-second order and Langmuir models, indicating that uranium ions were chemically adsorbed onto composite materials. Additionally, it was observed that higher temperatures promoted the uranium removal on GO/diatomite and rGO/diatomite, suggesting that the removal process was a spontaneous endothermic and exothermic reaction, respectively. In addition, the adsorption of U(VI) with GO/diatomite and rGO/diatomite was investigated using density functional theory (DFT) study. Configuration and adsorption energy were determined. The GO/diatomite composite materials can be a promising candidate as an adsorbent for the removal of uranium from aqueous solutions.

The application of Phalaris seed peel (PSP) for the production of biochar involves the pyrolysis process in an N 2 environment, resulting in the creation of a cost-effective sorbent. Two distinct modifications were conducted on the existing biochar (BC), employing just silicate (BC/SiO 2 ) and in combination with iron-silicate (BC/SiO 2 /Fe). Several analytical methods were used to look at the modified biochar’s physical and chemical properties. These included scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis-differential thermal analysis (TGA-DTA), and surface area analysis. Based on the initial investigations, it has been revealed that the use of silica and iron as the second modification is a more suitable approach for effectively retaining 133 Ba from liquid radioactive waste streams. The investigation of sorption kinetics and isotherms was conducted to enhance our understanding of the process. The Langmuir isotherm model demonstrates the most optimal correlation for sorption, yielding a maximum sorption capacity ( Q max ) of 31 mg/g. Furthermore, an evaluation was performed on the BC/SiO 2 /Fe sorbent material by subjecting it to a mixture of simulated radioactive liquid waste, which included 133 Ba, 60 Co, and 137 Cs.The experimental results indicate that BC/SiO 2 /Fe exhibits a comparatively higher sorption capacity for 133 Ba when compared to 60 Co and 137 Cs as competing ions.

Patient specific treatments for different cancers are currently being actively addressed through nuclear medicine. More recently, the identification of biomarker namely; prostate-specific membrane antigen (PSMA) expressed on the prostate cancer cell surface has been considered as a turning point in prostate cancer management using radiopharmaceuticals. In this treatment method, apart from radionuclide, organic ligands that target PSMA constitute an essential component. PSMA-11 and PSMA-617 are two important ligands that form the radiopharmaceuticals, [ 68 Ga]Ga-PSMA-11, [ 177 Lu]Lu-PSMA-617, which are currently powering the prostate cancer management, especially metastatic castration resistant prostate cancer (mCRPC) in most part of the world. Identification of efficient synthetic routes towards these highly expensive ligands is an important prerequisite to make this treatment modality more popular. In this account, the synthetic challenges that we circumvent during the solution phase synthesis of PSMA-11 and PSMA-617, through different chemical synthetic routes are demonstrated. Post-synthesis, both the ligands, PSMA-11 and PSMA-617 were successfully radiolabelled using 68 Ga, and 177 Lu, respectively, to generate corresponding labelled products [ 68 Ga]Ga-PSMA-11, and [ 177 Lu]Lu-PSMA-617, in good radiochemical purity.

In this study, a new nano-structure, N,P-doped graphene quantum dots (N,P-GQDs), were synthesized as multipurpose imaging agent for performing scintigraphy and magnetic resonance imaging (MRI). Some standard characterization methods were used to identify the nano-structure. In vitro cytotoxicity evaluation using MTT assay revealed that N,P-GQDs nanoparticles had no significant cytotoxicity after 24 and 48 h against normal (MCF-10A) and cancerous (MCF 7) human breast cell line in concentration up to 200 μg/mL. The N,P-GQDs were radiolabeled with Technetium-99m as 99m Tc-(N,P-GQDs) and the radiochemical purity was assayed by ITLC concluding RCP ≥ 95 %. The passing of 99m Tc-(N,P-GQDs) through 0.1 µm filter demonstrated that 70.8 % of particles were <0.1 µm. In order to perform scintigraphy, the 99m Tc-(N,P-GQDs) were injected to female healthy Wistar rats. The results showed that the radio-complex was captured and eliminated just by kidneys. Moreover, in vitro T 1 -weighted phantom MRI imaging showed that the N,P-GQDs have proper relaxivity in comparison to Dotarem ® as a clinically available contrast agent. The results showed that the N,P-GQDs have potential to be considered as a novel and encouraging agent for both molecular MRI and nuclear medicine imagings.

Using gamma and alpha spectrometers, the radioactive isotopes 226 Ra, 210 Pb, 232 Th, and 40 K were determined in three sediment cores from the Tam Giang-Cau Hai (TG), Thi Nai (TN), and Nai (DN) lagoons, and radiation risk indices were computed. The radioactivity concentrations of 210 Pb, 40 K, 232 Th, and 226 Ra were 55.46 Bq/kg, 675.78 Bq/kg, 67.22 Bq/kg, and 34.15 Bq/kg, respectively. The Ra eq , ADR, AEDE, I γr , AUI, Hex, and AGDE indices were 182.31 Bq/kg, 84.46 nGy/h, 0.10 mSV/y, 1.35, 1, 18, 0.49, and 598.71 µSV/y, respectively; the values of 40 K, 232 Th, AEDE, ADR, I γr , and AGDE were greater than the global average and UNSCEAR values. The radioactivity and radiation risk indices decreased in the order DN > TN > TG.

In proton therapy, the protons are used to destroy the cancer cells efficiently at the Bragg peak without much damage to normal cells. The protons can also produce neutrons, protons, and high-energy gamma rays through nuclear reactions with cancerous and healthy tissues as well as with beamline components. The effective observed dose in the therapy is enhanced due to the interaction of nuclear particles with cancerous tissues. Such nuclear particles can have several effects on drugs used in immunotherapy, such as immunotherapy in combination with proton therapy, which has been used to treat cancer. In the present investigations, the gamma, neutron, and protons interaction parameters of some immunotherapy drugs, such as dostarlimab, atezolizumab, ipilimumab, nivolumab, and pembrolizumab, are determined by using EpiXs, NGCal, and PSTAR software. It is found that the EBF and EABF for all selected immunotherapy drugs increase with increasing penetration depth, peaking at 100 keV. The peaking is more symmetric at a higher penetration depth of 40 mfp than at a lower one of 1 mfp. At lower energies of gamma photons, the EBF values increase exponentially, and at higher energies, they increase linearly with increasing penetration depth for all selected drugs. Mass attenuation factors are slightly higher for thermal neutrons than for fast neutrons for selected immunotherapeutic drugs, indicating that thermal neutrons more actively participate in these drugs than fast neutrons. The mass attenuation factor for both fast and thermal neutrons increases with increasing weight percentages of hydrogen and is found to be higher for thermal neutrons. This is the first study in the literature to investigate the radiation interaction parameters for immunotherapy drugs, and it is helpful in radiation therapy and dosimetry.

The demonstrations impact of CeO 2 on the radiation shielding properties of SiO 2 –B 2 O 3 –BaO–Li 2 O glasses has been investigated. The observed trend in density ρ ranged from 3.127 to 4.022 g/cm³, whereas the molar volume V m of these glasses decreased. The half-value layers (HVL), and mean free paths (MFP) of CL glasses reinforce the notion that the presence of Ce ions, particularly in CL 2 , enhances the ability of glasses’ to attenuate gamma rays. The effective electron density ( N eff ) increases with the addition of CeO 2 , suggesting a correlation between the enhancement of radiation shielding properties and the amount of CeO 2 incorporated into the glasses.