The International Commission on Radiation Units and Measurements (ICRU), in collaboration with the International Commission on Radiological Protection (ICRP), has introduced new operational quantities in ICRU Report 95....The International Commission on Radiation Units and Measurements (ICRU), in collaboration with the International Commission on Radiological Protection (ICRP), has introduced new operational quantities in ICRU Report 95. Among these, the personal dose Hp addresses the significant limitations of the currently used Hp (10), which can overestimate the effective dose by up to a factor of 5.5 at photon energies below 70 keV. These changes necessitate a re-estimation of dosemeter response to evaluate potential modifications in dose algorithms and detector design. In this study, the performance of CaSO4:Dy thermoluminescent dosemeter (TLD) badges was investigated for the new operational quantity Hp and compared with the existing Hp (10). The badge response was simulated over photon energy range 12.3-1250 keV using the Monte Carlo Simulation code FLUKA and benchmarked against experimental validation. To correct for energy-dependent overestimation at lower photon energies, a new dose evaluation algorithm for Hp was developed based on disc dose ratio (R12). The disc dose ratio (R12) refers to the ratio of absorbed doses measured in CaSO₄:Dy TL discs D1 and D2 positioned under different filtration conditions within the badge and serves as an energy-sensitive parameter for correcting the over-response of the dosemeter in terms of Hp. The proposed algorithm demonstrated strong compliance with IEC 62387:2020 performance criteria (acceptance range 0.71-1.67), with 95% of estimated Hp values lying within 0.9-1.3 of the delivered dose. These results confirm that CaSO4:Dy TLD badges, when combined with the improved algorithm, are fully compatible with the new operational quantities recommended in ICRU Report 95, ensuring reliable application in personnel dosimetry.
A method for the determination of gross alpha and beta activity concentrations in drinking water samples was established using liquid scintillation counting (LSC) through a series of batch experiments on water samples sp...A method for the determination of gross alpha and beta activity concentrations in drinking water samples was established using liquid scintillation counting (LSC) through a series of batch experiments on water samples spiked with 241Am and 90Sr/90Y. Counting windows were set to cover the full energy spectrum. α/β discrimination was investigated considering the use of calibration sources, spillover, and additional factors (e.g. scintillation cocktail type, acidic media, pH, sample-to-cocktail volume ratio) and was optimized. The optimized Pulse Shape Analysis value was set to 120 (τα + τβ = 5.511%). The impact of the total dissolved solids and sample-to-scintillation liquid volume ratio on counting efficiency was investigated. After optimization, the gross alpha and beta counting efficiencies were 26.6% and 37.6%, respectively. The measurement results demonstrated good agreement between the values obtained by LSC and the solid scintillation counting.
This study presents a comprehensive assessment of occupational exposure to ionizing radiation in diagnostic radiology in Côte d'Ivoire over the period 2018-2024. Based on spatial, collective, and individual dosimetric in...This study presents a comprehensive assessment of occupational exposure to ionizing radiation in diagnostic radiology in Côte d'Ivoire over the period 2018-2024. Based on spatial, collective, and individual dosimetric indicators, this analysis aims to quantify exposure levels and evaluate the effectiveness of radiological protection measures implemented nationally. A total of 78 facilities were monitored, over 90% of which were located in urban areas, particularly in Abidjan, the economic capital, which alone accounted for nearly 70% of the distributed thermoluminescent dosemeters (TLDs). This uneven distribution highlights disparities in access to dosimetric surveillance across the country. The annual collective dose (S) showed a significant increase from 94.54 man·mSv in 2018 to 1075.19 man·mSv in 2024 an increase of 1037.3%. The number of monitored workers rose from 187 to 595 over the same period, indicating expanded surveillance coverage. The average annual individual effective dose increased from 0.47 mSv in 2018 to 1.54 mSv in 2021 (a relative increase of 227.6%), before declining to 0.93 mSv in 2024 (a 39.6% decrease), reflecting the impact of corrective measures recommended by the national regulatory authority. Between 2018 and 2021, the proportion of workers exposed to doses exceeding 1 mSv/y rose sharply from 7.5% to over 90%, and continued to increase slightly, reaching 93.29% in 2024. These findings underscore the critical importance of maintaining regular monitoring and continuously improving radiological protection strategies. The study provides essential data to inform national policy and strengthen radiation safety in the medical sector.
PURPOSE: In radiotherapy, the primary goal is to eliminate cancer cells while minimizing damage to healthy cells. The low-energy electrons generated by radiation beams interact with deoxyribonucleic acid (DNA), causing d...PURPOSE: In radiotherapy, the primary goal is to eliminate cancer cells while minimizing damage to healthy cells. The low-energy electrons generated by radiation beams interact with deoxyribonucleic acid (DNA), causing double-strand breaks that are challenging to repair, ultimately leading to tumor cell death, since the radiation provokes a clustered damage and the tumor cells have defective or dysregulated DNA repair pathways. METHODS: We performed Monte Carlo simulations using standard GEANT4 classes, employing an atomistic model of DNA composed of 1122 base pairs, with each atom represented by a sphere corresponding to its van der Waals radius. DNA samples were exposed to mono-energetic electrons between 1 and 30 eV. The simulations incorporated the cross-sections of DNA strands and bases, and we ran 10 million electrons for each simulation. Three types of electron interactions with their positions x, y, z within the DNA volume were recorded: dissociative electron attachment (DEA), excitation, and ionization. Using the number and type of interactions at the atomic level caused by primary and secondary electrons, the number of single (SSB) and double (DSB) strand breaks in DNA was determined based on energy-deposition thresholds. RESULTS: We found that at energies <10 eV, DEA plays a more dominant role in DNA strand breaks than excitation and ionization, which are effective only when the deposited energy exceeds 8.22 eV for excitation and 17.5 eV for ionization. We observed that the DNA side exposed to the incident electrons was more subject to electron interactions. CONCLUSION: Our results show good agreement with experimental results in its global SSB and DSB, and our simulation accurately distinguished the breaks based on the type of interactions and the energy of the incident electrons. However, the absolute yields and the relative contribution of the different interaction types remain dependent on the modeled DNA geometry and irradiation conditions. Such a simulation reports DNA radiosensitivity at the atomic level and significantly contributes to the selection of radiopharmaceuticals targeting tumor cell nuclei such as those incorporating Auger electron emitters which are more effective than alpha and beta emitters.
OBJECTIVE: To compare photon-counting detector CT (PCCT) and energy-integrating detector CT (EID-CT) for abdominopelvic imaging regarding radiation dose and image quality. METHODS: This prospective study enrolled 94 adul...OBJECTIVE: To compare photon-counting detector CT (PCCT) and energy-integrating detector CT (EID-CT) for abdominopelvic imaging regarding radiation dose and image quality. METHODS: This prospective study enrolled 94 adults undergoing abdominopelvic CT. Objective image quality was assessed by measuring hepatic noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). Two blinded radiologists independently scored subjective image quality using a 5-point Likert scale. Radiation exposure was evaluated via CTDIvol, dose-length product (DLP), and scan length-normalized DLP (nDLP). RESULTS: PCCT significantly reduced radiation dose: CTDIvol by 57%, DLP by 62%, and nDLP by 57% (all P < .001). Concurrently, image quality improved:hepatic noise decreasing by 31% (P < .001), and SNR increased by 40-70% (P < .001); CNR increased 22-45% (P < .05). CONCLUSION: PCCT achieves substantial radiation dose reduction while improving objective image quality compared with EID-CT in abdominopelvic imaging. These findings support PCCT as a valuable tool for dose-optimised abdominal protocols.
Historical thorium bioassay data collected from Australian mine workers in the 1990s, including in vivo lung counting and thoron-in-breath (TIB) measurements, were re-evaluated using current dosimetric and biokinetic mod...Historical thorium bioassay data collected from Australian mine workers in the 1990s, including in vivo lung counting and thoron-in-breath (TIB) measurements, were re-evaluated using current dosimetric and biokinetic models. Revised daily thorium intakes from bioassay were compared with previous estimates to assess changes in the dose profile and potential implications for contemporary operations. Reanalysis revealed lower estimates of annual dose, including the number of workers assessed as exceeding 20 mSv. However, it was found that intakes derived from industry personal air sampling (PAS) underestimated intake by up to three-fold. This study determined that sensitive bioassay techniques, such as TIB using an electrostatic collection chamber, are feasible for detecting low thorium lung burdens in longer-term workers at current mineral processing operations involving naturally occurring radioactive materials (NORM). This study improves the accuracy of historical exposures and highlights that PAS protocols require improvement to enhance radiation protection practices in industries handling NORM.
The aim of the study was to model the dynamics of the peripheral blood count (platelets) in Russian nuclear workers chronically exposed to external gamma rays. Workers were divided in three groups depending on the total...The aim of the study was to model the dynamics of the peripheral blood count (platelets) in Russian nuclear workers chronically exposed to external gamma rays. Workers were divided in three groups depending on the total dose absorbed in bone marrow: <1.0 Gy, 1.0 to 2.0 Gy, ≥2.0 Gy. Factors such as the total dose, dose rate and duration of employment were considered as determinants of the platelet count dynamics. A dynamic regression model revealed statistically significant dose-response relationship in all study groups, while, in contrast, the analytical model fitted the data well only in the third group. The proposed method allows for the quantitative assessment of the time-dependent changes in the parameters of the peripheral blood relative to the individual initial level. This is critically important in case of chronic occupational exposure when cumulative dose increases with the increase in the duration of work with the ionizing radiation sources.
Two chamber types were used to investigate tritiated hydrogen (HT) deposition velocity in pasture soils in Rokkasho Village, Japan. A three-year experiment using an aerated chamber with atmospheric HT was conducted. The...Two chamber types were used to investigate tritiated hydrogen (HT) deposition velocity in pasture soils in Rokkasho Village, Japan. A three-year experiment using an aerated chamber with atmospheric HT was conducted. The HT deposition velocity correlated with soil temperature (r = 0.87), which peaked in summer when the soil temperature was high, with a maximum of 0.28 mm s-1. Changes in the aboveground plant biomass caused by harvesting three times in summer did not influence the velocity, and interannual increases in root biomass also did not correlate with the velocity. Experiments using a closed chamber with D2 gas injection were conducted in five pastures. The hydrogen deposition velocity correlated negatively with the volumetric water content. In addition, the soil temperature, soil moisture, and hydrogen deposition velocity obtained from the two experiments were fitted to an equation expressing soil conductance. It was suggested that the hydrogen deposition rate exhibits seasonal variation.
BACKGROUND: Establishing typical values is vital for radiation safety in paediatric fluoroscopically guided cardiac procedures (FGCP). AIM: To publish the first typical values for FGCP in a Mexican tertiary hospital. MET...BACKGROUND: Establishing typical values is vital for radiation safety in paediatric fluoroscopically guided cardiac procedures (FGCP). AIM: To publish the first typical values for FGCP in a Mexican tertiary hospital. METHODS: We retrospectively analyzed 136 procedures (2018-2024), stratified by procedure type, weight, and age. Kerma-area product (Pka) and cumulative air kerma (Ka,r) were collected. RESULTS: Typical values (median Pka) ranged from: <5 kg (2.84 Gy·cm2) up to 50-<80 kg (30.54 Gy·cm2). By age group <1 year (3.28 Gy·cm2) up to 10-15 years (20.63 Gy·cm2). No statistical difference was found between diagnostic and therapeutic procedures. CONCLUSIONS: Weight-stratified institutional typical values revealed critical disparities, notably a five-fold higher dose for therapeutic procedures in infants <5 kg (4.07 vs 0.80 Gy·cm2). While weight predicts diagnostic dose, complexity drives therapeutic exposure. These benchmarks enable local optimization and support future National DRL development.
Human exposure to naturally occurring radionuclides through food consumption contributes to the radiation dose. Radionuclides in the soil are transferred to foodstuffs through plant nutrient uptake. This study measured t...Human exposure to naturally occurring radionuclides through food consumption contributes to the radiation dose. Radionuclides in the soil are transferred to foodstuffs through plant nutrient uptake. This study measured the activity concentrations of 40K, 228Ra, and 226Ra in 37 mushroom samples from 15 species commonly consumed. Samples were analyzed using gamma-ray spectrometry employing a NaI(Tl) detector. The activity concentration (fresh mass) ranged from 10 to 252 Bq kg-1 for 40K, 0.6 to 6.0 Bq kg-1 for 228Ra, and 1.2 to 8.2 Bq kg-1 for 226Ra. The committed effective dose due to 1 y consumption of the mushrooms ranged from 1.2 to 1162 μSv y-1 across age groups 1, 5, 10, and 15 y and adults.
The present study is aimed at investigating dose homogeneity in a reference beta radiation field established for calibration of protection level devices and beta irradiation purposes as well as angular dose responses of...The present study is aimed at investigating dose homogeneity in a reference beta radiation field established for calibration of protection level devices and beta irradiation purposes as well as angular dose responses of the detectors on ISO rod and pillar phantoms. To this end, an automatic electromechanic system for beta irradiation and calibration (BIKS) was designed and manufactured with precise automatic control of the source shutter, stepper motors, detector rotation, and distance using microcontrollers. BIKS system enables to measure angular beta personal dose equivalents for skin-extremity Hp(0.07) and the lens of the eye Hp (3), including the corrections to standard reference conditions by using a multi-sensor. In beta radiation field, 2D spatial dose distributions were measured at 11 cm using radiochromic film dosimetry. Dose homogeneity is obtained better than ~91 ± 5%, on the average. Field uniformity was expanded using filters such as Hostaphan® PET films recommended by ISO 6980-1:2023 and other custom-designed filters. Angular dose responses of the detectors were measured over 0° to ±60° angle on ISO rod and pillar phantoms at 11, 20, and 30 cm. The measured differences in Hp(0.07) are <3% for all angles. BIKS system was also modelled using MC-based RayXpert® software. The estimated results are good agreement with those experimental ones.
Sikapizye E, Hayumbu P, Mumba N
… +4 more, Jacobs PJ, Pérez IA, García MÁ, Rathebe PC
Radiat Prot Dosimetry
· 2026 May · PMID 41904676
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Radon, a carcinogen for lung cancer is chemically inert, colourless, odourless, and a radioactive gas that originates from uranium and thorium radioelements. This review article presents radon concentrations and annual e...Radon, a carcinogen for lung cancer is chemically inert, colourless, odourless, and a radioactive gas that originates from uranium and thorium radioelements. This review article presents radon concentrations and annual effective dose (Ey) amongst workers in copper mines, as well as examining factors influencing radon levels. Findings indicate varying radon concentration levels ranging from acceptable values to those exceeding the occupational exposure limit of 1000 Bq.m-3. For instance, mean radon concentrations ranged from 6.6 Bq.m-3 to 2400 Bq.m-3 under mechanical ventilation, increasing by a factor of eight under nonmechanical ventilation. Similarly, Ey values ranged from 0.80 mSv.y-1 to above the 20 mSv.y-1 threshold, reaching as high as 34 mSv.y-1. Ventilation emerged as the prominent factor influencing radon concentration, alongside temperature, seasonal changes, and mining activities. The study recommends adequate ventilation and routine radon monitoring to improve air quality and protect workers.
This study explores the effectiveness of multi-purpose shelters using materials such as water (W), compacted waste, and polyester composites (C) containing lithium-boron compounds for shielding against solar particle eve...This study explores the effectiveness of multi-purpose shelters using materials such as water (W), compacted waste, and polyester composites (C) containing lithium-boron compounds for shielding against solar particle events (SPEs). Using Geant4 Monte Carlo simulations, the research evaluated different layer arrangements (C-W, W-C, W-C-W) to mitigate radiation doses from the two distinct February 1956 and October 1989 SPEs. Results showed that placing the composite layer on the exterior (C-W configuration) minimized secondary neutron production, achieving equivalent dose reductions of 82.9%-83.1% for protons and 72 3%-73.1% for neutrons in the October 1989 SPE, and 55 9%-56.5% and 33 2%-35.7% in the February 1956 SPE, respectively. Water outperformed other materials in the reduction of total equivalent dose in the phantom and remains the most practical choice due to the shelter's mass constraints and the ready availability. Using LiCO3-loaded composite instead of B4C-loaded composite slightly enhances the shielding performance up to 1.71%. By evaluating secondary particle fluences, particularly neutrons, in the proposed shelter under different layer arrangements and SPE conditions, the configuration-dependent equivalent dose differences were demonstrated. This study reveals how shielding performance can be optimized based on both material type and the energy spectrum of SPEs. Additionally, this study accounts for real-world volume constraints, offering practical guidance for spacecraft-compatible shield design.
INTRODUCTION: Dose audit and diagnostic reference levels should promote continuing optimization and patient protection. The objective of this work is to extend the diagnostic reference level concept by formulating benchm...INTRODUCTION: Dose audit and diagnostic reference levels should promote continuing optimization and patient protection. The objective of this work is to extend the diagnostic reference level concept by formulating benchmarks stratified by breast thickness and system type, and to make these benchmarks readily available to facilitate ongoing real-time audit. MATERIALS AND METHOD: After comparing the Facility diagnostic reference levels with the National one, the data set was divided into groups based on compressed breast thickness and system type. Benchmarks were established at the 95th percentile for individual categories, each combining a compressed breast thickness range with a system-type. RESULTS: A Dose Management System was used to compare the median values of each individual system against the relevant benchmark. This enabled ongoing, pertinent comparisons of data in real-time. CONCLUSION: Comparison to the relevant benchmark helps to quickly identify systems requiring investigation and possible optimization. This transforms dose auditing into a proactive tool rather than a retrospective one.
This study investigated the use of JavaScript (JS) to develop and test an open-access method, provided as a research resource, for predicting the decay and cumulative activity of iodine-131 (131I). A client-side JS engin...This study investigated the use of JavaScript (JS) to develop and test an open-access method, provided as a research resource, for predicting the decay and cumulative activity of iodine-131 (131I). A client-side JS engine was implemented to simulate decay using mono-exponential and piecewise multi-segmented models. Built-in JS functions were used to perform logarithmic and exponential operations. The tool's performance was validated against ion-chamber measurements from a thyroid phantom containing a pre-calibrated 131I capsule; moreover, measurement reliability was assessed. The phantom test showed a mean absolute error of 0.010 μSv/h for the mono-exponential model and 0.008 μSv/h for the multi-segmented model. The intraclass correlation coefficient (ICC) demonstrated excellent inter-observer agreement (ICC range: 0.998-0.999), while the mean intra-observer difference was 0.3% (SD = 0.2%; range: 0.1%-0.6%). By quantifying instrument-related error in advance, future studies may more confidently isolate biological variability, thereby supporting the robustness of patient-level interpretation and dose-prediction models.
This study evaluates radionuclide contamination and radiological exposure in terrestrial biota within the Lake Oubeïra ecosystem, El Kala National Park, Algeria. The soil core sample was analysed using gamma spectrometry...This study evaluates radionuclide contamination and radiological exposure in terrestrial biota within the Lake Oubeïra ecosystem, El Kala National Park, Algeria. The soil core sample was analysed using gamma spectrometry to quantify both natural and anthropogenic radionuclides. Using the ERICA Tier 2 assessment tool, total dose rates (TDRs) and risk quotients (RQs) were estimated for representative taxa including lichens, bryophytes, invertebrates, amphibians, and mammals. Results show that lichens and bryophytes experienced the highest exposures (TDR = 21.4 μGy h-1; RQ = 2.1), exceeding international ecological screening levels. Other taxa exhibited lower but non-negligible dose rates, indicating potential long-term ecological effects. The findings demonstrate that non-vascular plants serve as effective bioindicators of radiological stress and highlight the need for continued monitoring to preserve the ecological integrity of Lake Oubeïra.
Clearance levels, which are estimated by the International Atomic Energy Agency as the activity concentration corresponding to an effective dose of 10 μSv per year, are widely used; however, it has been pointed out that...Clearance levels, which are estimated by the International Atomic Energy Agency as the activity concentration corresponding to an effective dose of 10 μSv per year, are widely used; however, it has been pointed out that there is a large conservatism in their estimation. In the present study, we have attempted to examine the conservatism included in the derivation of clearance levels by selecting major radionuclides, considering the "factor of conservatism" included in the parameter settings and applying data on the latest statistical information from Japan. As a result, the factor of conservatism for activity concentration corresponding to an effective dose of 10 μSv per year was evaluated to be approximately 2-17 for major radionuclides. It is useful to take into account the fact that such conservatism is presented in the treatment of uncertainty in conformity assessment or in discussions on the stability of regulatory standards.
Magnetic Resonance Imaging (MRI) exposes patients to radiofrequency energy measured by the specific absorption rate (SAR), a key safety metric. This study aimed to compare SAR values in brain MRI scans performed at 1.5 T...Magnetic Resonance Imaging (MRI) exposes patients to radiofrequency energy measured by the specific absorption rate (SAR), a key safety metric. This study aimed to compare SAR values in brain MRI scans performed at 1.5 Tesla (T) and 3 T to inform safer imaging practices. A retrospective analysis of 200 adult brain MRI scans (100 at 1.5 T and 100 at 3 T) from King Khalid University Hospital was conducted. Data included SAR, demographics, scan parameters, and contrast use. Statistical tests assessed differences (P < .05). Brain SAR was significantly higher in 1.5 T scans (mean = 3.01 W/kg) than in 3 T (mean = 1.37 W/kg). Higher SAR values were noted in females and younger patients. Factors like image type, sequence, weight, flip angle, and contrast use significantly impacted SAR. SAR is more influenced by imaging parameters and patient characteristics than MRI magnetic field strength. Personalized MRI protocols and SAR monitoring are essential for patient safety.