A pocket-sized dosimeter/spectrometer with 1-cm3 cerium-doped gadolinium aluminum gallium garnet, GAGG(Ce), scintillation crystal was evaluated for its application in radioactivity measurements. The device was used (1) for the measurement of in situ ambient gamma dose rates, (2) as a car-borne dosimeter to measure dose rates along the roads, and (3) for recording the energy spectra from different environmental samples by placing it inside the lead shield. The dosimeter showed relative uncertainties better than 10% for dose-rate measurements of about 30 nSv h-1 and higher when measurements were performed for 30 min or longer. As a spectrometer, it revealed the typical features of environmental gamma-ray spectra. Energy spectra from radon charcoal canisters exposed to different indoor radon concentrations demonstrated the capability of the device to study variations in radon progeny gamma-ray spectra.
Medical linear accelerators (LINACs) operating above 8-10 MV produce induced radioactivity in machine components and treatment vault structures through photonuclear reactions and subsequent neutron capture. As the global installed base of LINACs exceeds 14,000 units and demand continues to grow, an increasing number of machines are reaching end-of-life, making the safe disposal of radioactivated components a pressing practical concern for healthcare institutions. This review covers the radioactivation process in medical LINACs, beginning with the physics of photonuclear interactions and neutron capture, including the giant dipole resonance and electronuclear reactions. The principal radionuclides identified in LINAC components and treatment room concrete are compiled from published measurements and Monte Carlo simulations across multiple vendors (Varian, Elekta, Siemens). The current regulatory frameworks governing the disposal of activated materials are compared, covering the International Atomic Energy Agency (IAEA) standards (GSR Part 3, GSG-17, GSG-18), the U.S. Nuclear Regulatory Commission (NRC) regulations (10 CFR Parts 20 and 61), the European Union Basic Safety Standards (Directive 2013/59/Euratom), and South Korea's Nuclear Safety and Security Commission (NSSC) Notice No. 2025-11, which establishes nuclide-specific clearance levels for self-disposal (the Korean regulatory equivalent of the IAEA concept of clearance) aligned with the IAEA's 10 µSv y-1 dose criterion. A practical step-by-step protocol for the disposal of radioactivated LINAC components is proposed to assist hospitals in achieving safe, compliant, and cost-effective waste management.
A number of communities in Ukwuani Local Government Area of Delta State are known to host several crude oil companies with exploration activities ongoing and may be responsible for the presence of high radon levels in drinking water. Radon (222Rn) has emerged as a major health concern due to its radiotoxic effects and radiation dose to internal organs. Therefore, this work aimed to measure radon levels in borehole water and assess the radiological risk. Thirty water samples were collected from borehole sources in the sampled area into containers. Analysis was done using a RAD7 device for radon measurement. After analysis, radon levels in the samples ranged from 1.373 Bq L-1 to 11.974 Bq L-1 with a mean value of 5.886 Bq L-1. The average radon value obtained here is below the US Environmental Protection Agency (US EPA) reference level of 11.1 Bq L-1. The World Health Organization (WHO) recommended limit is also above the mean radon value recorded in this study. This implies that borehole water in Ukwuani LGA is within radon safe limit with no significant threat to human health. These findings provide data to inform policy implementation and support interventions for safe drinking water resources and to serve as reference data for further studies on radon monitoring of other water sources within southern Nigeria.
To characterize routine kV cone-beam CT (CBCT) imaging dose in image-guided radiotherapy (IGRT) and to derive indication-specific local benchmark values using and DLP for clinical protocol optimization. This retrospective single-center audit included 300 CBCT examinations acquired on a Versa HD linear accelerator (Elekta AB, Stockholm, Sweden) using XVI v5.0.4. Examinations were grouped into 10 clinical indication workflows. For each CBCT, acquisition descriptors (CTDI phantom, kVp, total mAs, scan arc, FOV, bowtie, scan length) and dose indices were extracted. (mGy) was analyzed as recorded (reference value). DLP (mGy cm-1) was derived/verified as × scan length. Indication-stratified distributions were summarized using mean ± SD and 95% CI, with examination-level visualisation. An optional parameter-based estimation model () was evaluated as a quality-control layer using Bland-Altman analysis. Across all examinations, was 3.25 ± 3.06 mGy (range 0.123-10.109) with median 1.44 mGy (IQR 0.84-5.96). DLP was 80.27 ± 75.66 mGy cm-1 (range 2.21-255.81) with median 34.36 mGy cm-1 (IQR 18.55-150.38). Dose indices differed markedly by indication (≈49-fold between lowest and highest mean ). The highest mean occurred for Prostate IGRT (7.69 ± 1.95 mGy) and Pelvic nodes (7.21 ± 1.83 mGy), whereas Extremity setup (0.156 ± 0.027 mGy) and Brain SRS/SRT (0.263 ± 0.062 mGy) were the lowest. DLP was highest for Pelvic nodes (187.6 ± 47.5 mGy cm-1) and Prostate IGRT (169.1 ± 42.9 mGy cm-1). The estimation model showed minimal bias (Bland-Altman bias 0.007 mGy; 95% limits of agreement -0.321 to 0.335 mGy). Routine IGRT CBCT dose on Versa HD/XVI shows strong indication dependence, driven by protocol selection and scan extent. The reported indication-resolved /DLP distributions provide a practical basis for local reference levels and targeted optimization of high-dose workflows (pelvic/abdominal) while preserving low-dose protocols for cranial/extremity indications.
Radionuclide 131I is of vital importance in radiation protection and nuclear medicine. Its internal dose is mainly concentrated in the thyroid. The S value is a key parameter in the calculation of internal dose. It represents the radiation-weighted energy deposition per unit mass of the target organ when the radionuclide undergoes a single decay of the source organ. As the thyroid is both the source organ and the target organ, its mass and shape may affect the S value. Therefore, this paper studies the influence of thyroid mass and shape on the S value. In this study, based on the thyroid model of the ICRP adult mesh-type reference computational phantoms (MRCPs), a series of thyroids with different masses were generated by proportionally scaling the thyroid volume while maintaining its original shape. The influence of mass on the S value (thyroid←thyroid) is then systematically analyzed using the Geant4 Monte Carlo simulation platform. To further explore the influence of shape, this paper reviews the S values (thyroid←thyroid) simulated by other researchers using thyroid models of different shapes and compares them with the research results of this paper. The research results show that the S value has a good inversely proportional relationship with thyroid mass. It can be precisely fitted as a linear function of the reciprocal of mass, with a correlation coefficient (R2) of 0.9999. The result of this formula has a deviation of within 5.67% compared with the results in the literature. This study demonstrates that the difference in thyroid shape has a relatively weak influence on the S value, and the empirical formula fitted in this paper may have good universality and reliability.
Nuclear energy is widely regarded as a critical part of the pathway toward a secure, low-carbon electricity grid, yet long-term management of used nuclear fuel remains a persistent challenge. Although technically viable options for interim and consolidated storage exist, public concern and community opposition - rooted in historical distrust and risk perception - continue to complicate siting decisions. In response, recent federal efforts have emphasized collaboration-based approaches and community engagement, though empirical evidence on the effectiveness of different engagement strategies remains limited. This study examines how the structure and delivery of community engagement influence changes in public attitudes toward hosting interim used nuclear fuel storage facilities. Using survey data from 13 educational workshops around the United States, we evaluate: (1) the inclusion of trust-building content prior to technical content, and (2) engagement format, comparing online and in-person workshops. Analyses focus on participant changes in perceptions of safety, risk, and support for hosting, using the Wilcoxon rank-sum test and other non-parametric hypothesis tests on surveys conducted before and after workshops. Results indicate that workshop participation is associated with some measurable attitude changes, with significant (p < 0.05) differences in response variability for some questions across workshop formats. In particular, when comparing nuclear energy to other clean energy sources, in-person workshop participants are substantially more likely to gain a more favorable opinion of nuclear energy than online participants. These findings contribute empirical evidence on how trust-building and delivery mode shape outcomes in public engagement on complex and contested energy policy issues such as storage of used nuclear fuel.
Permanently implanted iodine-125 ( 125 I) brachytherapy sources are a radiological technique used to treat localized cancers. The TG-43U1 group of the AAPM emphasizes the importance of calculating the dose distribution around brachytherapy seeds before their clinical use or approval for therapeutic purposes. In this work, we examined the dosimetric properties of the BEBIG iodine-125 IsoSeed I25.S06 source for LDR brachytherapy, based on the TG-43U1 guidelines. Dose calculations were carried out using Monte Carlo simulations with Python. The results are interesting. The analysis aimed to determine several dosimetric parameters, such as the radial dose function g L (r), the anisotropy function F(r,θ), and the dose rate constant Λ were determined. Furthermore, Comparison with previous studies reveals a good level of agreement. The Python code appears to provide results in good agreement with expected values for the dosimetry parameters.
On 2 May 2019, a recovery operation involving a 137 Cs source in a research irradiator resulted in the breach of a source capsule containing approximately 77.1 TBq. Following this incident, the dispersal characteristics of the radioactive material were evaluated in the context of emergency response. The results showed that the dispersal behavior with the building ventilation system was consistent with previous recommendations for response to a radiological dispersal device in guidance first proposed in 2006. The 2006 guidelines stated that for most modern large buildings, intervention via ventilation systems is not likely to be an effective countermeasure.
Spent-fuel dissolution produces multi-nuclide, high-activity aerosols. Gross α/β CAMs are prone to interference and slow response, limiting timely dose assessment and alarms. We developed an integrated multiparameter synchronous detection system to simultaneously measure activity concentration, spectra, and particle size. The instrument integrates sampling and optical sizing (0.1-10 μm) with a silicon barrier (α), thin-window proportional (β), and 2 × 2 NaI (Tl) (γ) detectors. Signals are digitized (14-bit/100 MS s-1) for pulse-shape discrimination and 8,192-channel spectrometry. Performance followed ISO 11929/Currie. Standard sources and mixed-nuclide aerosols were used for calibration, linearity, response, and misclassification tests; stability was assessed over 720 h (50 L min-1, 60 s integration). Detection efficiencies were 26.3% (241Am α), 42.5% (90Sr/90Y β), and 31.2% (137Cs γ). Minimum detectable activities were 8.5 × 10-7 Bq cm-3 (241Am), 9.2 × 10-7 Bq cm-3 (239Pu), and 3.1 × 10-6 Bq cm-1 (90Sr/90Y). Dynamic tests gave T90 = 17.5 s and T95 = 22.3 s; α/β misclassification <5%; linearity across five orders (R2 = 0.9987). Compared with a representative CAM, spectral resolving power improved ≈5-fold and response time shortened 10-20 times. Energy and efficiency drift over 720 h were ≤±2% and ≤±3%. Multi-parameter acquisition reduces dose-assessment bias from nuclide misidentification and size assumptions and shortens alarm latency to <30 s in high-background, multi-nuclide environments, supporting ALARA and process control during spent-fuel dissolution.
To evaluate the relationship between specialized radiation safety training and the effectiveness of interdepartmental coordination among a multidisciplinary cohort of healthcare professionals. This cross-sectional, mixed-methods study surveyed 173 healthcare professionals from a tertiary care hospital in Saudi Arabia (69 nurses, 52 medical doctors, 52 medical technologists) using a validated questionnaire. Training adequacy and coordination effectiveness were measured via Likert scale items, while open-ended questions identified barriers and areas for improvement. Data were analyzed using Kruskal-Wallis tests for professional role comparisons and Spearman's rank correlation to assess the link between training and coordination. Across the three professional groups, training scores ranged from 2.89 to 3.67, with medical technologists reporting significantly higher scores (3.67 ± 0.55) compared to nurses (3.11 ± 0.67) and doctors (2.89 ± 0.67). Similarly, coordination scores ranged from 2.83 to 3.15, with medical technologists reporting significantly higher scores (3.15 ± 0.62) compared to nurses (2.91 ± 0.61) and doctors (2.83 ± 0.73) (H = 32.651, p < 0.0001). Spearman's correlation revealed no significant relationship between training levels and coordination effectiveness (ρ = -0.038, p = 0.6157). Qualitative analysis identified limited access to radiation safety resources (10.4%, n = 18), unclear role definitions and responsibilities (6.9%, n = 12), heavy workload and staff shortages (6.9%, n = 12), and insufficient awareness of radiation risks (6.9%, n = 12) as primary barriers. Individualized radiation safety training may be insufficient to guarantee effective interdepartmental collaboration. To establish a sustainable safety culture, healthcare organizations must move beyond didactic education toward systemic solutions, including standardized protocols, clear role definitions, and resource-integrated workflows.
Air gaps in multi-well cell culture plates can disrupt electronic equilibrium and introduce uncertainties in delivered dose during in vitro irradiation experiments. This study evaluated the impact of different bottom-up irradiation setups on short-term cell viability using an RW3 solid water phantom system. MCF-7 cells were irradiated with 6-MV photons (200-cGy) under four experimental configurations. One-way ANOVA demonstrated no statistically significant differences among setups [F(3,8)=0.503, p=0.691]. Tukey HSD post-hoc analysis confirmed the absence of significant pairwise differences (p>0.05). A subsequent power analysis (η 2 =0.159; Cohen’s f=0.434) revealed an observed power of 0.15. These findings indicate that additional bolus or RW3 configurations do not significantly affect short-term cell viability when bottom-up geometry and appropriate buildup conditions are maintained.
The illegal trade of rhinoceros horns continues to threaten wildlife populations and undermine conservation efforts worldwide. This study explores the feasibility of using existing radiation portal monitors to detect rhinoceros horns implanted with radioactive sources during international sea transportation. By leveraging the Gamma Detector Response and Analysis Software, a series of simulated pass-bys were conducted under controlled variables, including fill capacities, material densities, and 60Co source strengths. The models incorporated a 6.10-m (20-ft) shipping container with a keratin horn configuration, simulating realistic concealment scenarios. Background environments were modeled after Denver, CO, to reflect elevated natural radiation conditions. Detection performance was assessed using theoretical probability of detection, incorporating International Atomic Energy Agency Nuclear Security Series No. 1 standards for operational consistency. Results show that increased cargo capacity and denser shielding materials, such as aluminum and stainless steel, reduce probability of detection, though such solid-block shielding is unlikely in real-world cargo. Shadow shielding from empty or lightly filled containers enhanced detection capability by reducing background noise. Furthermore, modeling scenarios with multiple horns improved probability of detection, aligning with seizure patterns observed in sea transport trafficking cases. While the study does not determine the minimum detectable activity due to law enforcement sensitivities, it demonstrates the plausibility of radiation portal monitor systems identifying radiologically tagged horns under realistic shipping conditions. The findings support the concept of radiation tagging as a cost-effective, scalable strategy to deter trafficking, increase seizure rates, and reinforce international conservation efforts without disrupting trade flow or requiring infrastructure overhauls.
VARSKIN is becoming more commonplace in nuclear medicine departments to calculate skin dose from droplet or surface contamination due to its accessibility and ease of use. VARSKIN uses simplified dose kernels, which give dose estimates quickly; however, the disadvantage is that some accuracy may be compromised. The aim of this article was to independently compare the VARSKIN (v2.1) skin dose module against Geant4 for typical skin contamination scenarios. Realistic skin contamination scenarios were modeled in Geant4 including droplet and surface contamination. Three droplet volumes (10, 30, and 50 μL) were considered as well as an infinitely thin disk source (A = 1 cm2) to model surface contamination. Four basal depths (70, 140, 220, and 370 µm) were considered in combination with two glove layers defined by 0.1 mm and 0.2 mm of natural rubber (ρ = 0.92 g cm-3) as well as an absent glove layer. The Geant4 models were then replicated as closely as possible using VARSKIN (v2.1) skin dose module. Forty-four (44) radionuclides were considered giving a total of 2,112 direct comparisons of instantaneous skin dose rates between VARSKIN (v2.1) and Geant4. Most data (86%) were within ±50% (relative) difference between VARSKIN and Geant4 with a median difference of only +4.0% for all data. However, the 95% confidence interval was wide at -29% to +210%, showing a large positive skew. This skewness is predominantly caused by large relative differences observed for photon emitting radionuclides including 57Co, 51Cr, 67Ga, 123I, 125I, 129I and 111In. However, the differences were low in absolute terms for these radionuclides. Despite large relative differences between VARSKIN and Geant4 for certain radionuclides and geometries, the differences were low in absolute terms. Overall, we conclude that VARSKIN (v2.1) is a reliable tool for skin dose assessment for the radionuclides and geometries studied in this article.
The concentration of uranium in 51 samples of groundwater from the Chengalpattu District of Tamil Nadu was measured with an LED fluorimeter. The uranium concentration exhibited a range of 0.02 µg L-1 to2.814 µg L-1, with a mean value of 0.347 µg L-1. The uranium concentrations in this study are significantly below the recommended limits set by various agencies of 30 µg L-1 (WHO 2011) and 60 µg L-1 (AERB 2004). Lifetime average daily dose and hazard quotient were calculated to assess the chemical toxicity, and excess cancer risk was calculated to assess the radioactive risk. The parameter was compared with the limits of safety specified by different agencies. The carcinogenic and non-carcinogenic risk due to water consumption was much less than the permissible limits for both children and adults. From the analysis, it is found that water can be considered to be safe for use.
Virtual reality holds promise as a tool for recruiting new individuals into the health physics profession and for providing realistic experiences for both junior and senior radiation protection professionals. Virtual environments are constructed using models of objects, also known as assets. This work presents a collection of radiological assets unavailable elsewhere, which could be immediately applied in fully immersive three-dimensional environments as well as used for more standard two-dimensional applications. Radioactive sources, shields, nuclear electronics, and radiation detectors are included. Strategies for producing realistic but performance-optimized assets are included. A fully immersive virtual reality game about radiation protection incorporating the assets presented in this paper is currently being designed by the authors to interest students in nuclear science and engineering at high schools and colleges. The resulting realistic assets are further available upon request to any interested individuals for incorporation into not-for-profit outreach or professional-level training using virtual reality experiences.
Virtual reality (VR) technology has been increasingly explored for creating immersive visual and interactive experiences in education and outreach, including applications related to radiation. A video game project named DoseBusters was created by a team of primarily undergraduate students as a method of outreach to attract interest in nuclear sciences while teaching fundamental radiological science and radiation protection principles. DoseBusters employs instructional dialog, experiments, and puzzle-like gameplay scenarios to engage students and the public. The Unity game engine was selected for building and deploying the game application, with Blender used for creating three-dimensional models of game assets. The Meta Quest line of headsets was used for testing. DoseBusters employs simple point-source gamma radiation assumptions for its real-time dose rate calculations. It implements shielding calculations that exclude buildup and scatter. Real-world measured data are used to accurately model detector sensitivities and spectroscopic measurements. A tutorial room environment uses a series of experiments to teach players about radiation physics, also serving to validate certain elements of the radiation physics simulation. Further minigames can be played to provide more depth and experience relating to source surveying and shielding principles. As part of the project's development, numerous realistic radiation and environmental three-dimensional models were created, enhancing player immersion. Future work will involve using newly created environments for gameplay scenarios. Testing of all game play will ultimately be conducted with user feedback surveyed afterwards. Improvements to the game's radiation simulation are also planned, including the addition of alpha and beta radiation.
Activity concentrations of 226Ra, 232Th, and 40K radionuclides were determined in various brands of bottled drinking water commonly available in the local markets of Greater Dhaka City; additionally, the annual effective dose following the ingestion pathway was assessed. Radioactivity of 226Ra in the bottled water (purified, mineral, and drinking) samples varied from 0.61 ± 0.27 Bq L-1 to 10.64 ± 1.34 Bq L-1 with a mean value of 4.73 ± 1.02 Bq L-1. For 232Th, the concentration ranged between 0.35 ± 0.27 Bq L-1 and 5.71 ± 3.37 Bq L-1 with a mean of 2.97 ± 1.61 Bq L-1; for 40K, it ranged from 3.48 ± 2.92 Bq L-1 to 93.58 ± 26.74 Bq L-1 with a mean of 36.31 ± 10.63 Bq L-1. Purified bottled water exhibited the highest activity concentrations of 226Ra and 40K, whereas drinking water showed the highest 232Th concentration compared to purified and mineral bottled water samples. Infants received higher annual ingestion doses compared to children and adults. The average value of the threshold consumption rate remained below the limit. The 226Ra shows statistical significance, whereas 232Th and 40K are the opposite; 226Ra shows greater heterogeneity.
Neonatal radiography is essential in neonatal intensive care units (NICUs) for diagnosing and monitoring critical conditions. However, the use of ionizing radiation in fragile neonates - particularly in repeated chest and abdominal x rays - raises concerns about cumulative radiation exposure and its potential long-term health effects. This study aimed to quantitatively assess the entrance surface dose (ESD) received by neonates during chest and abdominal radiography in two NICUs in Saudi Arabia and to compare with the international diagnostic reference levels (DRLs). A prospective, quantitative study of 100 neonates (50 in each hospital) on clinically justified chest and abdominal radiographs with mobile digital x-ray units was conducted. ESD was estimated from technical exposure parameters [tube voltage (kVp), milliampere-seconds (mAs), and focus-to-skin distance (FSD)] using the NRPB-recommended method. Correlation analyses and multiple linear regression were conducted to find the dose variation predictors. The average ESD was 0.48 ± 0.18 mGy in Hospital A and 0.49 ± 0.08 mGy in Hospital B with no statistically significant difference between the two hospitals. These results are well over ~5-10 times the international neonatal DRLs. ESD was significantly correlated with mAs (r=0.67) and patient thickness (r=0.76), and with kVp (r=0.54) in a moderate level of association; however, kVp and mAs were only weakly correlated (r=0.11). Regression analysis showed that patient thickness, mAs, and kVp were significant independent predictors of ESD (adjusted R2 = 0.65, p < 0.001). Neonatal radiation doses were found to be significantly elevated compared with the international reference levels, highlighting the need for immediate optimization. Dose reduction techniques like protocol standardization, elevated kVp at low mAs setting, beam collimation, and filtration must be used. These findings provide baseline data for establishing regional neonatal DRLs in Saudi Arabia and support future optimization studies using anthropomorphic phantoms.
Early detection and effective monitoring of gastrointestinal injury are needed for efficient medical management of the radiation-exposed victims. This study evaluated fatty acid-binding proteins (FABP1, FABP2, and FABP6) in combination to accurately predict and monitor radiation-induced gastrointestinal injury in C57Bl/6 mice. The response of FABPs was checked upon exposure to a range (2.5 Gy-20 Gy) of gamma radiation doses and their availability in serum from 2 h to 7 d. These alterations were correlated with structural changes in the intestine and the expression of genes encoding tight junction proteins, Zona occludens-1 and Occludin. Tissue-specific expression was also checked. FABP2 expression was found abundant and specific to the intestine, where it co-localized with FABP1 and FABP6. An increase in serum FABPs was noted in a dose- and time-specific manner, which correlated with radiation-mediated intestinal injury and downregulation of Zona occludens-1 and Occludin. FABP1, FABP2, and FABP6 were found to be upregulated at 9 Gy and above and were available in serum within 24 h of exposure. FABP1 and FABP2 were detected in serum between 24 h and 72 h, whereas FABP6 had a prolonged time window (24 h to 5 d). In serum, FABP1, FABP2, and FABP6 peaked at 24 h, 48 h and 72 h, respectively, suggesting that the three FABPs in combination can detect GI injury as early as 24 h. These proteins displayed reliable specificity based on ROC curve construction. Together, FABP1, FABP2, and FABP6 could detect and assess the progression of radiation-induced gastrointestinal injury rapidly, which may facilitate in managing exposed individuals following radiological emergencies.
The Fukushima Daiichi Nuclear Power Plant accident in 2011 released substantial amounts of radiocesium (137Cs, 134Cs) and smaller amounts of radiostrontium (90Sr) into the environment. Despite extensive remediation, consumer hesitancy to consume agricultural products from the region persists. This study presents a radioanalytical assessment for a selection of wines and ciders produced in the Fukushima Prefecture. Measurements of 137Cs and 90Sr were performed to allow comparison with national and international food safety regulations and to support efforts aimed at revitalizing local agriculture and public confidence. Results indicate that radionuclide levels in all tested beverages were well below applicable regulatory limits, indicating a correspondingly low potential radiological risk associated with their consumption.
