Search Results (2,439)

This study is carried out to investigate the radiological characteristics and mineralogical controls of natural radioisotopes (²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K) in granitic pegmatites from Abu Zawal Area (AZA) in the Eastern Desert of Egypt. The analyzed pegmatites, containing thorite, zircon, monazite, ferrocolumbite, and fergusonite, exhibit exceptionally high radioactivity concentrations of ²³⁸U ≤ 568; ²³²Th ≤ 674; ²²⁶Ra ≤ 170 (Bq kg⁻¹), significantly exceeding the world average permissible limits (35, 30, 30, and 400 Bq kg⁻¹ for ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K, respectively). Comprehensive radiological assessment reveals severely elevated radiological impact associated with Ra_eq ≤ 1243 (Bq kg⁻¹) and hazard indices (H_ex≤ 3.36; ELCR ≤ 12.2 × 10⁻³) surpassing international safety thresholds (H_ex ≤ 1; ELCR ≤ 1 × 10⁻³). The observed disequilibrium between ²³⁸U and ²²⁶Ra (with ²²⁶Ra activities approximately half those of ²³⁸U) is attributed to the geochemical mobility of radium and potential selective leaching during late-stage hydrothermal alteration, while the overall enrichment of the uranium series over the thorium series is linked to the predominance of uranium-bearing minerals like zircon and fergusonite in these pegmatites. Mineralogical analysis demonstrates distinct radiation patterns: thorite and monazite dominate Th-derived gamma radiation and radon/thoron exhalation, while zircon and fergusonite control U enrichment and decay chain disequilibrium. Notably, nominally low-activity minerals like ferrocolumbite contribute to localized radiation hotspots through U/Th co-concentrations. The calculated absorbed dose rates ranged from 182 to 978 (nGy h⁻¹) and annual effective doses show extreme spatial variability correlated with Th-rich mineral assemblages. Full article

Thyroid cancer is the most common type of endocrine cancer. Most cases are called differentiated thyroid cancer (DTC), which includes papillary, follicular, and hurthle cell types. DTC usually grows slowly and has a good prognosis, especially when found early and treated with surgery, radioactive iodine, and thyroid hormone therapy. However, cancer can come back sometimes even years after treatment. This recurrence can appear as abnormal blood tests or as lumps in the neck or other parts of the body. Being able to predict and detect these recurrences early is important for improving patient care and planning follow-up treatment. In this view, this research explores different machine learning algorithms and neural networks to effectively predict DTC recurrence. A total of 17 classifiers were utilized for the experiment, namely, logistic regression, random forest, k-nearest neighbours, Gaussian naïve Bayes, multi-layered perceptron, extreme gradient boosting, adaptive boosting, gradient boosting classifier, extra tree classifier (ETC), light gradient boosting machine, categorical boosting, Bernoulli naïve Bayes, complement naïve Bayes, multinomial naïve Bayes, histogram-based gradient boosting, and nearest centroid, followed by building an artificial neural network. Among the classifiers, ETC performed best with 95.3% accuracy, 95.1% precision, 87.92% recall, 98.18% specificity, 91.21% F1-score, 98.84% AUROC and 97.66% AUPRC on the first dataset, and 99.47% accuracy, 94.83% precision, 98.62% sensitivity, 99.54% specificity, 96.65% F1-score, 99.95% AUROC, and 99.37% AUPRC on the second dataset. To improve model interpretability, Shapley Additive Explanations (SHAP) was also used to explain the contribution of each clinical feature to the model’s predictions, allowing for transparent, patient-specific insights into which factors were most important for predicting recurrence, thereby supporting the proposed model’s clinical relevance. Full article

Long-term monitoring of radon (²²²Rn) and thoron (²²⁰Rn) radioactive gases has been used in earthquake forecasting. Seismic activity before earthquakes raises the levels of these gases, causing abnormalities in the baseline values of radon and thoron time series (RTTS) data. This study reports applications of kernel density estimation (KDE) and wavelet-based density estimation (WBDE) to detect anomalies in radon, thoron, and meteorological time-series data. Anomalies appearing in the RTTS data have been assessed for their potential correlation with seismic events. Using KDE and WBDE, radon anomalies were observed on 12 March, 15 August, 17 September, in the year 2017, and 19 January 2018. Thoron anomalies were recorded on 12 March, 15 August, 17 September 2017, and 28 February 2018. Irregularities in RTTS were observed several days before seismic events. Anomalies in RTTS, detected using KDE, successfully correlated five out of nine seismic events while WBDE identified four anomalies in RTTS which were successfully correlated with the corresponding seismic events. The wavelet transform has been used to reduce noise at higher decomposition levels in radon and thoron time series. Findings of the study reveal the potential of radon and thoron time series that can be used as precursors for earthquake forecasting. Full article

Higher olefins are a class of alkenes widely used as intermediates in the production of essential consumer and industrial products. This radiolabel disposition and partial mass balance study investigated the distribution and excretion of four ¹⁴C-radiolabelled alpha higher olefins (i.e., 1-octene, 1-decene, 1-hexadecene, and 1-eicosene) in male Wistar rats following a single oral dose (100 mg/kg). Blood, liver, kidney, adipose tissue, urine, and faeces were collected and analysed for total ¹⁴C-derived radioactivity. Urinary elimination was rapid, with approximately 70% and 90% of total radioactivity recovered in urinary excreted within 24 and 48 h, respectively. Excretion patterns showed a clear chain-length-dependent trend: shorter-chain olefins (C8, C10) exhibited higher urinary excretion, indicating greater systemic absorption, while longer-chain olefins (C16, C20) were primarily eliminated via faeces, suggesting limited intestinal uptake. Tissue distribution was minimal in blood, liver, and kidney, but adipose tissue retention increased with chain length. Total recovery of administered radioactivity in the analysed matrices was low, ranging from 17% to 60%. Importantly, because exhaled ¹⁴CO₂ and volatile parent compounds were not captured, the missing fraction cannot be quantified and the balance cannot be considered closed. All in all, the current study describes the partial disposition of higher olefins and highlights the influence of molecular size and lipophilicity on the biological fat, though further studies are required to fully characterise their metabolic profile and total elimination kinetics. Full article

Differentiated thyroid carcinoma (DTC) is the most common malignant endocrine tumor, with a generally favorable prognosis. Imaging, including iodine radioactive isotope scintigraphy (IRIS), is crucial for diagnosis and follow-up. While ¹³¹I has long been used for both therapeutic and diagnostic purposes, ¹²³I is reserved for diagnostic imaging due to its shorter half-life and γ emissions. This review highlights the utility of ¹²³I scintigraphy, especially in pre-treatment assessment and dosimetry for DTC. It is particularly valuable before radioiodine (RAI) ablation, providing accurate imaging in patients with iodine-refractory (IR) or biochemically incomplete response (BIR) DTC. When compared to post-therapeutic ¹³¹I scans, ¹²³I scintigraphy appears to have a lower sensitivity for detecting metastatic lesions, particularly in lymph nodes and lungs. However, its diagnostic performance compared to low-dose diagnostic ¹³¹I is more variable, with some studies suggesting superiority due to the absence of stunning. Further research is needed to standardize its use and optimize its role in guiding DTC management. Full article

Objectives: This study aimed to assess whether low-iodine diet (LID) adherence is associated with therapeutic response in papillary thyroid carcinoma (PTC), specifically in relation to post-therapeutic thyroglobulin (Tg) release as a surrogate marker for the acute radiation-induced response following radioactive iodine (RAI) therapy. Methods: This retrospective study included 895 patients with PTC treated with RAI. LID adherence was assessed using the urine iodine-to-creatinine (I/Cr) ratio, with <66.2 μg/g Cr defined as good adherence. The Tg ratio (ratioTg), calculated by dividing post-RAI Tg (measured 7 days after RAI) by pre-RAI Tg, was used to reflect the magnitude of the radiation-induced Tg release. Patients were stratified by ratioTg (≤1 vs. >1), and associations between LID adherence and therapeutic response were analyzed within each group. Results: Well-adherent patients exhibited significantly higher ratioTg compared to poorly adherent patients (15.7 ± 2.2 vs. 8.9 ± 1.3, p = 0.007). Among patients with ratioTg > 1 (n = 630), LID adherence was independently associated with improved therapeutic response (OR, 2.004; 95% CI, 1.270–3.162; p = 0.003). No such association was observed in patients with ratioTg ≤ 1 (n = 265; p = 0.546). Conclusions: The clinical benefit of LID appears to depend on the presence of a certain magnitude of radiation-induced Tg release. RatioTg may serve as a useful marker for identifying patients likely to benefit from LID. Full article

Uranium production tailing ponds in Kamyanske (Ukraine) are objects of increased radioecological danger. Violation of the stability and integrity of containment dams threatens the uncontrolled spread of radionuclides. The purpose of this study is to comprehensively assess the factors affecting the technical condition and environmental safety of the Sukhachivske tailing dam. The study included a visual inspection and detailed geophysical work using the natural pulse electromagnetic field of the Earth (NPEMFE) method. This method was chosen to identify hidden filtration paths and stress zones in the body of the earth dam. An analysis of the spatial distribution of waterlogging, filtration, and fissuring in the hydraulic structure was performed. Based on the results of the NPEMFE survey, six zones with varying degrees of waterlogging and stress–strain states of the structure were identified. The presence of externally unmanifested filtration paths and suffusion areas was established, and a tectonic scheme of fracture development in the dam body was compiled. A correlation was found between the dominant azimuths of crack extension (70–79° and 350–359°) and the directions of regional tectonic lineament zones, at the intersection of which the tailing pond is located. It has been established that modern tectonic movements along fault zones create zones of permeability, which serve as primary pathways for water filtration and further development of suffusion. This conclusion introduces a new tectonic feature for risk diagnosis and monitoring of similar hydraulic structures. Full article

Prostate cancer is the third-leading cause of cancer death in men. Prostate-specific membrane antigen (PSMA) is a robust biomarker that is expressed in approximately 80% of patients diagnosed with prostate cancer; several theranostic strategies have emerged based upon targeting this biomarker. This report describes a dimeric aptamer complex (DAC) which is selective for PSMA⁺ cancer cells and is amenable to derivatization with additional diagnostic and therapeutic molecules. Confocal microscopy confirmed the selective nature of the DAC for PSMA⁺ LNCAP tumor cells. In addition, the affinity of the DAC for the PSMA protein was determined to be 2.16 ± 0.15 nM using biolayer interferometry (BLI). In proof-of-principle studies, this DAC was biotinylated (BioDAC; A10), complexed with streptavidin (SA), and radiolabeled with the positron-emitting radioisotope zirconium-89 (⁸⁹Zr: t_½ = 78.4 h, β⁺: 22.8%) to form the radiopharmaceutical [⁸⁹Zr]Zr-Df-SA-BioDAC ([⁸⁹Zr]Zr-A12). Acute biodistribution studies revealed elevated levels of radioactivity in PSMA⁺ tumors when compared to PSMA^- tumors. Radioactivity retention in the kidney was high due to the presence of streptavidin, while radioactivity retention in the liver was comparable with that of other radiolabeled aptamer complexes. Accordingly, the data suggests that the radiopharmaceutical will need to be redesigned using a strategy that is not reliant on a biotin–streptavidin paradigm before additional preclinical assessments are made and clinical translation can be attempted. Full article

Mining activities generate vast quantities of waste each year, including mine tailings, bauxite residue, waste rock, and various metallurgical slags. Although these materials have traditionally been regarded as environmental liabilities, many possess physical and chemical properties that make them promising candidates for use in construction. This review synthesizes recent research on the utilization of major mining waste streams, with particular emphasis on pavement applications and other construction materials. The findings indicate that bauxite residue exhibits both pozzolanic and filler characteristics, demonstrating potential in asphalt mastics, asphalt mixtures, and other construction products. Nonetheless, its widespread adoption is constrained by issues such as high alkalinity, leaching risks, and concerns related to naturally occurring radioactivity. Mine tailings can be a substitute for fine aggregates and cement in a range of mixtures, though challenges, including pronounced material variability and environmental risks, persist. Waste rock offers favorable geotechnical properties for use in road bases and embankments, while metallurgical slags (e.g., copper, nickel, and lithium slags) provide functional pozzolanic activity and suitable aggregate qualities. Across all waste types, their incorporation into construction materials can conserve natural resources, reduce material costs, and support circular-economy and low-carbon development objectives. However, progress remains contingent upon advancements in material standards, pretreatment technologies, environmental protection measures, and large-scale field validation. Overall, this review underscores both the significant potential and the practical challenges associated with transforming mining waste into valuable and sustainable construction resources. Full article

We report on the study of the immobilization process of non-radioactive rhenium (Re), a chemical analogue of technetium-99 (⁹⁹Tc), in compounds based on magnesium potassium phosphate (MKP), as well as the possibility of enhancing their properties with iron-bearing additives/fillers. Powdered Re₂O₇ was used as the initial Re-containing source. Because of the solubility and high leachability of Tc (VII), which is also volatile at high temperatures, its immobilization for long-term storage and disposal poses a serious challenge to researchers. Taking this into account, low-temperature stabilization technology based on MKP, a cementitious material, is currently considered promising. We prepared experimental specimens based on Re-incorporated MKP matrices and analyzed their microstructure in detail using analytical methods of X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Considering that iron-bearing substances can reduce Tc (VII) to the lower-valence form Tc (IV), which is more stable, attention was also paid to evaluate the effect of fillers (Fe₂O₃, Fe₃O₄, Fe, FeS and blast furnace slag (BFS)) on strength, oxidation state, and water resistance (expressed as leaching cumulative concentration). The addition of fillers ensures the formation of denser compounds based on MKP after 28 days of curing under ambient conditions and increases their mechanical strength. The oxidation state of Re and the reduction from Re (VII) to Re (IV) was estimated using X-ray-absorption near-edge structure (XANES) analysis. Considering the Re leaching concentrations from tests using the ANS-16.1 standard in water, enhanced leachability indices (LI) for Re from MKP matrices were determined with the addition of iron-bearing fillers. Overall, the average LI values were greater than the minimum limit, indicating their acceptance for disposal recommended by the U.S. Nuclear Regulatory Commission. Full article

Background: Papillary thyroid cancer (PTC) incidence is rising, particularly among Adolescents and Young Adults (AYA, 15–39 years). However, data on PTC characteristics in the AYA population, especially from the Middle East, remain limited. This study aims to describe the clinicopathological features of PTC in AYA patients treated at a large tertiary center in Qatar. Methods: A retrospective chart review was conducted for AYA patients diagnosed with PTC between May 2015 and December 2020 at Hamad General Hospital, Qatar. Data on demographics, tumor characteristics, histopathology, staging, risk stratification, and treatment were extracted and analyzed. We stratified the cohort based on sex. Results: We studied 326 AYA patients (mean age 33.0 ± 5.2 years); the majority were females (72.7%) and were mostly of Asian origin (51.5%). Most patients underwent total thyroidectomy (77.6%), while 22.4% underwent partial thyroidectomy. Histologically, classic PTC was most common (83.38%), followed by the follicular variant (16.00%). Capsule invasion occurred in 21.04%, vascular invasion in 11.76%, and lymphatic invasion in 14.38%. Most patients were at low ATA risk (68.61%), with intermediate (20.06%) and high risk (11.33%) less common. Distant metastases were rare (0.3%), and 59.1% received Radioactive iodine (RAI). Compared to females, males had larger tumors (mean 2.65 cm vs. 2.01 cm, p = 0.0009), higher rates of vascular invasion (22.4% vs. 7.7%, p < 0.001), affected lymph nodes (mean 4.2 vs. 2.4, p = 0.0223), and ATA high-risk proportions (23.5% vs. 7.0%, p < 0.001). Conclusions: This study provides the first detailed characterization of PTC in AYA patients from Qatar. While confirming female predominance, males exhibited more aggressive features (larger tumors, higher LN involvement, and ATA risk). These findings emphasize the need to consider gender-specific differences in managing PTC within the AYA population. Full article

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, with limited treatment options for patients with locally advanced or metastatic disease. Endoscopic ultrasound (EUS)-guided intra-tumoral radioactive implantation has emerged as a minimally invasive approach to enhance local tumor control while minimizing systemic toxicity. Among the available isotopes, phosphorus-32 (³²P) microparticle brachytherapy has demonstrated promising outcomes, including significant tumor regression, reductions in CA 19-9, and higher rates of tumor downstaging and surgical conversion when combined with systemic chemotherapy. Compared with stereotactic body radiotherapy (SBRT), ³²P delivers higher intratumoral radiation doses, spares adjacent healthy tissues, and can be administered during ongoing chemotherapy without treatment interruption. Additionally, preliminary evidence suggests that ³²P may modulate the tumor microenvironment, improving vascularity and enhancing chemotherapy efficacy. The procedure shows high technical success and a favorable safety profile, with minimal serious adverse events. Future directions include prospective randomized trials to validate its impact on survival, optimize dosing, and establish treatment protocols. EUS-guided intra-tumoral ³²P brachytherapy holds potential as a key component of multimodal therapy, bridging local tumor control and systemic disease management in PDAC. Full article

Thorium carbide (${\mathrm{ThC}}_{2\pm x}$) nano-structured thin disc-like pellets were produced from thoria nanoparticles (${\mathrm{ThO}}_2$-NP) and multi-walled carbon nanotubes (MWCNT). These composites are to be studied as a target material candidate for radioactive ion beam (RIB) production via nuclear reactions upon impact with high-energy proton beams on a stack of solid pellets. The ${\mathrm{ThO}}_2$-NP precursor was produced via precipitation of thorium oxalate from a thorium nitrate solution with oxalic acid and subsequent hydrothermal oxidation of the oxalate, creating the thoria nanoparticles. The ${\mathrm{ThO}}_2$-NP were then mixed with MWCNT in isopropyl alcohol and sonicated by two different methods to create a nanoparticle dispersion. This dispersion was then heated under medium vacuum to evaporate the solvent; the resulting powder was pressed into pellets and taken to an inert-atmosphere oven, where it was heated to 1650 °C and carbothermally reduced to ${\mathrm{ThC}}_{2\pm x}$. The resulting pellets were characterized via XRD, SEM-EDS, and Raman spectroscopy. The resulting thorium pellets exhibited, at most, trace levels of the oxide precursor. Furthermore, the nanotube structures were still present in the final product and are expected to contribute positively towards faster radioisotope release times by lowering isotope diffusion times, which is required for the efficient extraction of the shortest-lived (<1 s half-life) radioisotopes. Full article

The article presents a comprehensive comparative performance evaluation and validation of composite adsorbents based on the Se-derivative of 4-amino-N′-hydroxy-1,2,5-oxadiazole-3-carboximidamide for U (VI) recovery from complex multicomponent aqueous media. Our results indicate the composite materials to be comparable to, and in some cases to surpass, existing adsorbents in recovery efficiency. Under static sorption conditions for trace U (VI) from real multicomponent solutions (tap, river, and sea water), the sorption efficiency reached 80–98%, while the distribution coefficients ranged from 10⁴ to 10⁶ cm³ g⁻¹. The sorption-selectivity properties of the materials were evaluated in the presence of competing ions (EDTA and oxalate ions), which possess a high chelating capacity and a strong tendency to form complexes with uranium. The dependence of sorption efficiency on the concentration of these ions and the solution pH was investigated. The possibility of reusing the materials over multiple sorption-desorption cycles was assessed. An optimal regenerating eluent agent was identified (NaHCO₃/NH₄NO₃), providing a desorption efficiency of >95% without degrading the material’s sorption properties over repeated cycles. Using a combination of physicochemical methods, including sorption techniques, the mechanism of uranium sorption and its dependence on the material structure were determined. The efficiency of uranium recovery from multicomponent natural waters was also investigated under dynamic conditions over repeated sorption-desorption cycles. The results demonstrate through comparative analysis that the developed composites exhibit a high sorption capacity and possess a high practical potential for the concentration and recovery of uranium from high-salinity solutions with complex composition. Full article

Background: Accurate localisation of non-palpable breast lesions is essential for the optimization of breast-conserving surgery (BCS) outcomes. While wire-guided localisation (WGL) remains widely used, radioguided techniques—including Radioguided Occult Lesion Localisation (ROLL) and Radioactive Seed Localisation (RSL)—have been proposed to improve margin clearance, reduce reoperations, and enhance patient outcomes. This umbrella review aimed to critically appraise and synthesize evidence from systematic reviews and meta-analyses on radioguided localisation techniques for non-palpable breast lesions, with a primary focus on comparison with wire-guided localisation (WGL). Methods: A comprehensive literature search was conducted using PubMed/Medline and the Cochrane Library databases for eligible systematic reviews/meta-analyses published until 2024, focusing on outcomes such as relative efficacy, safety, margin positivity, re-excision rates, operative efficiency, and patient-related outcomes. Results: In total, 35 records were retrieved, but only 10 evidence-based articles were selected. Radioguided approaches achieved high localisation success (often exceeding 95%) and fewer positive margins compared to WGL, while reoperation findings were mixed. Operative/localisation times were generally shorter for radioguided methods, with comparable specimen volume/weight and favourable safety profiles. Conclusions: Radioguided localisation methods provide superior or at least equivalent outcomes compared with WGL and can improve workflow; Sentinel Node and Occult Lesion Localisation (SNOLL) may support combined lesion localisation and sentinel node evaluation. Further high-quality, standardized comparative studies are needed to define the optimal resection ratio, protocol standardization and cost of the radioguided techniques and other newer probe-guided methods. Full article