External beam radiation therapy (EBRT) is widely used for uveal melanoma to preserve the eye and achieve effective tumor control. However, late side effects remain a concern, reinforcing the need for dose reduction to mitigate long-term toxicity. This study aims to validate a 3D-printed ocular tissue-equivalent anthropomorphic phantom, with enhanced anatomical accuracy based on the Alderson Radiation Therapy Phantom, through end-to-end dosimetric analysis using radiochromic film and thermoluminescent dosimeters (TLDs) for research and quality assurance (QA) applications in EBRT. Gafchromic EBT3 films and LiF:Mg,Ti microcube TLDs were used for dose assessment in target volume and organs at risk (OAR). Calibration and irradiation were performed using a Varian Clinac iX and a TrueBeam linear accelerator with a 6 MV photon beam. Film dosimetry, with films positioned in axial and oblique planes, was processed using the Film2Dose software and compared to the Varian Eclipse® treatment planning system (TPS) via gamma analysis. For TLD analysis, lower limit of detection verification, reproducibility tests, individual calibration, and cone beam computed tomography (CBCT) dosimetry were made prior to the treatment dosimetry to ensure accuracy. For treatment dosimetry, TLD samples were placed in regions of interest (i.e. lens, eye fundus, PTV, and optic nerve) for point dose verification and compatibility analysis against the TPS. In the film analysis, maximum dose uncertainties of up to 16% were observed in low-dose regions (<10% of prescribed dose). Gamma analysis yielded a mean passing rate of 100% for 2%/2 mm/10% threshold criterion. All TLDdose measurements demonstrate statistical compatibility with TPS predictions using Z-score-based compatibility analysis. Uncertainties below 5% were found in experimental measurements and TPS point dose assessment. These results indicate the robustness of the dosimetric methods employed and support the validation of the developed 3D-printed, tissue-equivalent anthropomorphic ocular phantom for research and quality assurance applications in EBRT.

Accurate and reliable mass measurement of special nuclear materials (SNMs) is of vital importance for nuclear safeguards. Although the point model assumption simplifies the derivation of the neutron multiplicity counting (NMC) equation, it limits the quantitative analysis capability for SNMs with large masses. Given the high cost and widespread deployment of thermal neutron multiplicity counters, improving their performance in safeguard supervision is of practical significance. Therefore, in this work, the bias induced by the point model assumption was quantified using the one-speed neutron transport equation and Monte Carlo simulations. Furthermore, artificial neural network (ANN) models were employed to replace some of the mathematical relations in the NMC equation, to enhance the measurement capability of the NMC method for larger-mass SNMs. By comparing the calculation results of the transport equation and the Geant4 toolkit for the leakage multiplication factor and factorial moments, it is found that the point model systematically underestimates the process of neutron multiplication within the material. The degree of underestimation is directly proportional to the mass and volume of SNM, and has a certain correlation with the geometric shape of the material. By integrating the ANN algorithm into the NMC equation, the verification results show that the ANN model can significantly reduce the measurement bias of SNM mass for the NMC equation. Specifically, for the plutonium scrap multiplicity counter, the application of the ANN model can reduce the measurement deviation of [240]Pu mass from 19.22% to 1.79%, and can also predict the mass of [239]Pu in SNM.

In order to realize broad-range search in optimization problems of material selection and their arrangement in the design of Beam Shaping Assembly (BSA), a new method combining the generalized perturbation theory (GPT) to the hill climbing algorithm is proposed. In this method, all possible candidate solutions neighboring a current solution are thoroughly considered, and difference of each of these candidates from the current one in the objective function and the constraints is rapidly estimated by GPT. To examine the proposed method, a one-dimensional slab problem is treated with the diffusion equation. The proposed method with 13 different initial conditions is tested, and the solution satisfying all criteria is obtained in 9 cases. It is also demonstrated that the final material arrangement is not significantly dependent on the initial conditions. Through the present work, it is confirmed that our proposed algorithm has a potential to find excellent solution in the optimization problem of material arrangement in BSA.

The choice of an optimum energy fluorescence source for in vivo x-ray fluorescence (XRF) can be challenging. This article describes a Monte Carlo study that systematically investigates possible sources for the in vivo XRF measurement of strontium in bone, with the ultimate goal of improving current measurement systems. A benchmarked EGS5 model was used to test source energies ranging from 17.2 keV to 21.7 keV to determine which source energies maximized the strontium XRF signal. A systematic search was then conducted to find potential radioisotope sources in the optimal energy range and simulations were performed of each source. The overall conclusion is that [103]Pd is a promising alternative to the [109]Cd and [125]I radioisotope sources used in prior systems. Monte Carlo studies suggest, however, that best performance could be obtained using a portable XRF gun with a rhodium target, although this would deliver a higher radiation dose.

The requirement to distinguish between depleted metallic uranium (DU) and natural metallic uranium (NU) is essential in nuclear forensics, regulatory enforcement, nuclear fuel fabrication and environmental monitoring. Traditional laboratory-based methods offer high accuracy but are impractical for on-site measurement. This research develops a portable gamma spectrometry-based methodology for identifying DU and NU in real-time, non-destructively. The study utilizes a NaI(Tl) based gamma spectrometer to measure characteristic emissions from uranium isotopes and its daughter products. Key gamma peaks, particularly those at 92 keV ([234]Th) and 186 keV ([235]U), were analysed to derive isotopic ratios indicative of the material type. Emphasis was given on choosing right gamma peak and adjustment for x-ray contribution in 92 keV peak. Estimated activity ratio of [235]U to [234]Th of five natural uranium samples was greater than or equal to 0.046 and the activity ratio of five depleted uranium sample found to be less than 0.046, which validated the methodology. The results demonstrate that, with proper calibration, and spectral analysis, portable gamma spectrometry can serve as an effective tool for real-time uranium isotope identification in applications ranging from nuclear safeguards and non-proliferation to environmental monitoring and emergency response.

High-energy (10 MeV) electron beam (e-beam) irradiation was investigated as a non-thermal intervention for vacuum-packaged frozen sliced squid (Loligo spp.). Absorbed doses ranged from 1 to 5 kGy, with storage at -18 °C for eight weeks. A core challenge was dosimetry mapping within deep-frozen bulk geometries, since standard B3 thin-film dosimeters lose chemical validity below their glass transition temperature. This was addressed using the Electron Gamma Shower version 5 (EGS5) Monte Carlo code. A dual-beam configuration achieved a Dose Uniformity Ratio (DUR) of 1.18, confirmed via B3 dosimetry in a density-matched phantom, with agreement within 1.7%. Sensitivity analysis showed a 10% fluctuation in phantom density did not raise the DUR beyond 1.28, confirming robustness against packaging variation. Using a high-bioburden challenge model with an initial Total Viable Count (TVC) of 6.8 log CFU/g, the 2 kGy treatment reduced TVC to 2.6 log CFU/g, a 4.2-log reduction, remaining below the 6.0 log CFU/g threshold throughout storage. Lipid oxidation, tracked via Peroxide Value (PV) and Thiobarbituric Acid Reactive Substances (TBARS), followed zero-order kinetics; the 2 kGy treatment yielded a final TBARS concentration of 0.68 mg MDA/kg, below the 1.0 mg MDA/kg sensory rejection threshold. Total color difference (ΔE*) and Warner-Bratzler shear force changes remained within commercially acceptable limits. A discriminative Triangle Test (ISO 4120:2021) detected no statistically significant organoleptic difference, though post-hoc power analysis indicated limited power for strict equivalence. These results support 2 kGy dual-beam e-beam processing as a technologically sound, quantitatively validated intervention for frozen cephalopod safety and quality assurance.

This report details a 55-year-old male with liver metastases from Adenoid Cystic Carcinoma (ACC), enrolled in a study on Boron Neutron Capture Therapy (BNCT) utilizing Boronophenylalanine (BPA) as a carrier. The patient underwent two BNCT sessions. Within three months of the first BNCT, the tumor area remained stable, and pre-existing telangiectasia completely disappeared. No irreversible adverse effects of BNCT were observed. Despite ongoing dose exploration, this study highlights BNCT's therapeutic potential for ACC-related liver lesions.

The activity concentrations of primordial radionuclides Radium-226 ([226]Ra), Thorium-232 ([232]Th) and Potassium-40 ([40]K) in soil and fertilizer samples from tobacco-growing areas in Karnataka state were determined by Gamma-ray spectrometry using a NaI(Tl) detector. The average activity concentrations of [226]Ra, [232]Th and [40]K in soil samples were found to be 33.44 ± 2.3, 93.79 ± 3.4 and 663.4 ± 6.2 Bq.kg[-1] respectively. The physicochemical parameters of the soil were determined by standard methods and analyzed systematically in this paper. The correlation between these parameters and natural radionuclides was examined using Pearson's correlation co-efficient. The results showed that the fertilizers and physicochemical parameters affect the natural radionuclides in soil. The data related to forest soil shows slightly lesser activity of radionuclides than in the cultivated soil for the same type of rock distribution. Notably, some parameters showed positive correlation coefficients with radionuclides, while others showed negative correlations. This phenomenon is discussed in detail within the paper. It was found that physical parameters, such as sand, silt, and clay, have a significant impact on the natural radionuclides. Similarly, the effects of Potential of Hydrogen (pH), Soil Organic Carbon (SOC), Moisture Content (MC), and Electrical Conductivity (EC) on the natural radionuclides are explored thoroughly in this study. Additionally, the local geology plays a crucial role in the variation of natural radionuclide levels. The measured activity concentrations of these radionuclides found in soil, and the calculated radiological hazard indices, were assessed against internationally accepted values.

Radon ([222]Rn), Thoron ([220]Rn) and their progeny activity concentration is measured to estimate the inhalation dose. These measurements are important in indoor as well as in the occupational environments like Uranium mines and Thorium processing industries. Inhalation dose is estimated from the measured activity concentration of Radon, Radon progeny (EECR: Equilibrium equivalent Radon concentration), Thoron concentration, Thoron progeny concentration (EECT: Equilibrium equivalent Thoron concentration). For quick assessment of high Radon/Thoron activity areas, especially for mitigation purpose, active methods are generally used, but for inhalation dose assessment time integrated measurements using passive SSNTDs (Solid state nuclear track detectors) is the most reliable technique. Passive detectors have their extensive suitability for long-term and large-scale monitoring. LR-115 and CR-39 are the most extensively used SSNTDs in the field of radon and neutron dosimetry. In the present work, comparison between LR-115 and CR-39 based Radon, Thoron and Progeny dosimeters is carried out and the experimental results were compared with theoretical calculations.

This study investigates unsteady magnetohydrodynamic (MHD) boundary-layer flow and bioconvection of a Casson nanofluid over a revolving paraboloid with varying thermophysical properties. We formulated a mathematical model to analyze heat and mass transport under the influence of thermal radiation, viscous dissipation, chemical reaction with activation energy, and motile microorganisms, based on coupled nonlinear partial differential equations (PDEs). The governing PDEs were transformed to a system of nonlinear ordinary differential equations (ODEs) with appropriate similarity transformations and then numerically solved by the bvp4c algorithm in MATLAB. The Casson parameter, magnetic field, curvature, and mixed convection parameters have a strong influence on velocity profiles. With the increase of radiation, more heat generation, and thermophoresis, the temperature profile rises while the fluid concentration lowers with increasing Damköhler number and activation energy. In addition, it is observed that the density of the bioconvective microorganisms decreases as the Peclet and bioconvection Lewis numbers increase. Also, it is seen that with the increase of Peclet and bioconvection Lewis numbers, the density of the bioconvective microorganisms decreases. The results reveal that the radiative and bioconvective transport has a significant influence in the non-Newtonian fluid flow regimes and these findings can be used for predicting the optimization of thermal management in biomedical devices, bioreactor design, and crude oil extraction processes.

Breast cancer is the second most common malignant neoplasm among women worldwide. Computed tomography (CT) plays an important role in diagnosis, staging, follow-up, and metastatic assessment. This study aimed to evaluate the role of chest CT in patients with breast neoplasms at a public hospital and to compare dosimetric parameters with Diagnostic Reference Levels (DRLs), based on CTDIvol and dose-length product (DLP). Related malignancies (ovarian and cervical) were included for preliminary analysis. A retrospective study of 334 elective outpatient chest CT examinations performed in 2025 was conducted. All patients were female, with a mean age of 59.04 ± 12.57 years, and most (65.40%) were within the recommended screening age range (50-74 years), while 15.19% were aged 40-49 years. DICOM data were obtained from two 64-slice CT scanners: Philips Incisive (CT A) and Canon Aquilion (CT B). CTDIvol and DLP values for CT A were stratified by clinical indication. Percentile analysis (P25-P75) showed lower CTDIvol values for CT A (4.06-5.82 mGy) compared with CT B (4.99-8.83 mGy), while DLP values were higher in CT A (146.97-201.45 mGy cm) than in CT B (94.51-201.49 mGy cm). Median CTDIvol values were 4.70 and 7.65 mGy, and DLP values were 169.42 and 141.36 mGy cm for CT A and CT B, respectively. The P75 values remained below international DRLs for adult chest CT and CT for radiotherapy planning. These findings highlight the importance of continuous dosimetric assessment to optimize CT protocols and ensure radiation protection in patients undergoing treatment.

Low-energy gamma-ray attenuation measurements are strongly influenced by coherent (Rayleigh) scattering and geometrical effects, particularly under non-ideal broad-beam experimental conditions. In this work, a Monte Carlo-based correction methodology using the MCNP6 code was developed to improve the accuracy of mass attenuation coefficient measurements in 3D-printed polymeric materials. Experimental measurements were performed for acrylonitrile butadiene styrene (ABS), polyethylene terephthalate glycol (PETG), and polylactic acid (PLA) using [241]Am and [137]Cs gamma-ray sources in combination with a 2 × 2″ NaI(Tl) scintillation detector. Monte Carlo simulations were conducted to reproduce both the experimental measurement geometry and an idealized narrow-beam configuration, enabling the determination of correction factors for low-energy attenuation measurements affected by scattering effects. Additional simulations were performed within the 40-100 keV energy range to develop mathematical fitting functions capable of estimating scattering and geometrical corrections as a function of photon energy. Aluminum samples were also analyzed as a reference material to validate both the experimental methodology and the MCNP6 simulations. The obtained attenuation coefficients were compared with NIST XCOM reference data, showing maximum deviations of 4.94% for the [137]Cs measurements (aluminum) and 9.50% for the corrected [241]Am measurements (PLA). Results demonstrated that the proposed correction methodology significantly improved agreement between experimental and reference attenuation coefficients, particularly for low-energy photons strongly affected by Rayleigh scattering and geometrical effects. The proposed approach enables reliable attenuation measurements to be performed even under non-ideal experimental conditions, particularly in laboratories without access to highly collimated measurement systems or high-intensity radioactive sources. This methodology contributes to the assessment of 3D-printed polymers as alternative materials for radiation shielding and nuclear technology applications.

Accurate quantification of condensate film thickness in large-diameter wet gas transmission pipelines represents one of the more challenging problems in nuclear measurement technology. In misty flow, liquid is distributed as fine aerosol droplets across the full cross-section of the pipe, making conventional gamma densitometry unreliable. A preconditioner system - consisting of a static helical impeller and a circular nozzle - converts this misty regime into a quasi-annular configuration in which the liquid coalesces as a continuous film on the inner pipe wall, making the geometry tractable for circumferential gamma scanning. This paper presents a Geant4/GATE Monte Carlo radiation transport study of a 360-detector circumferential scanning array designed for a full-scale 32-inch (DN-800, Schedule 40) steel pipe with an outer diameter of 813 mm, inner diameter of 778.04 mm, and wall thickness of 17.48 mm. A [137]Cs source of 40 mCi activity, positioned at the geometric centre of the pipe, was modelled with an axial lead collimator reproducing the laboratory pencil beam. Three condensate-equivalent calibration phantom sectors - 15 mm, 20 mm, and 27 mm thick, wood, density 750 kg/m[3], angular opening 67° - were placed against the inner wall at angular separations of 20°, 51°, and 88°. The model was implemented in two campaigns: the original thesis configuration, and a fully-documented reconstruction (Geant4 11.0.0/GATE 9.2) incorporating explicit lead collimation, a 7% detector energy-resolution model, and 1.92×10[9] primary histories. The reconstructed run gives sector relative count rates of 0.9255 ± 0.0011, 0.9021 ± 0.0011 and 0.8696 ± 0.0011 for the 15, 20 and 27 mm phantoms, referenced to the condensate-free gas region at a no-film baseline of 13144 cps per detector element. Weighted regression yields an effective linear attenuation coefficient of μ=0.00517±0.00003mm[-1] for the wood phantom at 0.750 g/cm[3], and inverting this calibration recovers the three film thicknesses to within 0.06 mm of nominal. Angular detection errors across six measurement zones range from 0.42% to 2.06%, with a total circuit error of only 0.04% for the complete 360° rotation. Agreement between the legacy and reconstructed campaigns is 2.1% in normalised RMSE across the sampled regions. The central-source configuration yields a baseline count rate approximately seven times higher than an equivalent external-source arrangement, owing to the halving of steel wall traversal. To the authors' knowledge, this is the first reported Monte Carlo optimisation study of a circumferential gamma scanning array at DN-800 scale, providing a validated computational framework for annular film profiling in large-bore wet gas infrastructure.

Radon-222 is odorless and colorless and is highly soluble in water. Radon-222 cannot be detected by other means except measurements. When taken internally or inhaled through volatilization of water, it may lead to internal irradiation which targets the lungs and gastro-intestinal tract. The current study seeks to find out the radon-222 concentrations in 50 water samples collected from Lagos State University campus, Nigeria in November 14, 2024, using passive LR-115 Type II solid state nuclear track detectors. The results indicated concentrations in the range 3.7 ± 0.3 to 40.7 ± 8.3 Bq/L with an average concentration of 18.4 ± 3.5 Bq/L exceeding the NESREA recommended level of 11.1 Bq/L by 74%. Although the surface geology of the Ojo area is dominated by sedimentary formations of the Dahomey Basin, elevated radon concentrations can still occur due to upward migration of radon from deeper uranium-bearing basement rocks through fractures and faults, as well as from radium adsorbed on clay minerals and organic matter within the sedimentary sequence. The concentrations are up to 3.7 times the standard value. The average annual effective dose is 0.07 mSv/y for adults, 0.03 mSv/y for children and 0.02 mSv/y for infants, below WHO's 0.1 mSv/y standard value. The average lifetime excess cancer risk is 0.193 × 10[-3], which exceeds USEPA's risk limit of 10[-4] in 94% of the samples, signifying high risk of cancer. The risk categorization indicates 26% low risk (≤11.1 Bq/L), 50% medium risk (11.1-22.2 Bq/L) and 24% high-concentration sources (>22.2 Bq/L). It is below WHO's standard value of 100 Bq/L but exceeds the standard in some cases and thus has real health implication on consumers of untreated water in the university campus.