A new compact three-element Extremity Ring Badge (ERB) dosemeter has been developed for extremity dose monitoring of Indian radiation workers. This three-element dosemeter is based on indigenously developed CaSO4:Dy-Tefl...A new compact three-element Extremity Ring Badge (ERB) dosemeter has been developed for extremity dose monitoring of Indian radiation workers. This three-element dosemeter is based on indigenously developed CaSO4:Dy-Teflon discs as a thermoluminescent detector placed between suitable filters in a plastic holder. The dosemeter is designed and calibrated to measure the dose equivalent in terms of operational quantity Hp(0.07) at finger location. It can measure the doses from gamma, beta, and low-energy X-ray radiations and distinguish the beam quality (photon/beta) as well. The design features and results of the experimental studies conducted towards development of ERB dosemeter are presented. The dosemeter demonstrated satisfactory performance in the European Radiation Dosimetry Group (EURADOS) interlaboratory exercise (IC2024ext). The response of all test dosemeters were well within the trumpet curve, as per IEO 14146:2018 criteria, which validates the dose evaluation algorithm used for estimation of Hp(0.07) in the IC2024ext exercise.
While fundamental radiological protection standards remain consistent for operating and decommissioning nuclear power plants (NPPs), the unique challenges of decommissioning require a specialized program. This study anal...While fundamental radiological protection standards remain consistent for operating and decommissioning nuclear power plants (NPPs), the unique challenges of decommissioning require a specialized program. This study analyzes the radiological characteristics of decommissioned NPPs and proposes a tailored protection program. Key findings indicate that although total radioactive inventory decreases, radiation dose rates in work areas can fluctuate significantly during the removal and movement of structures and components. The risk of internal exposure and alpha contamination increases due to fine aerosols generated during cutting. The proposed program includes five key elements: ALARA (As Low As Reasonably Achievable), effective access control and monitoring, high-frequency radiological surveys, contamination control, and prevention of internal exposure. This approach aims to optimize radiation exposure, prioritize the removal of high-radiation sources, expand real-time monitoring, and enhance worker training. The study's results aim to bolster safety and establish a robust radiological protection system for future Korean NPP decommissioning efforts.
Three-dimensional localization of neutron-emitting materials is crucial for minimizing personnel radiation exposure during nuclear decommissioning and nuclear safety activities. To address this challenge, this study prop...Three-dimensional localization of neutron-emitting materials is crucial for minimizing personnel radiation exposure during nuclear decommissioning and nuclear safety activities. To address this challenge, this study proposes a localization method based on double-scattering principle and a dedicated reconstruction algorithm. This study is comprised of two main parts. First, a double-layer scintillator array detector was designed. Its key parameters were optimized to achieve a balance between coincidence detection efficiency and spatial resolution. Second, a three-dimensional localization algorithm was developed. This algorithm determines the optimal imaging plane and reconstructs a heatmap, leading to three-dimensional localization. The performance of the double-scattering imaging system was evaluated via simulations. The results demonstrated that the neutron source can be localized within a defined spatial area with centimeter-level accuracy. This study provides a practical solution for the three-dimensional localization of neutron-emitting materials and demonstrates its significant application potential in the field of nuclear decommissioning.
To validate the thyroid dose assessment performed at Nagasaki University after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, the influence of 131I biodistribution on the direct in-vivo counting measurements...To validate the thyroid dose assessment performed at Nagasaki University after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, the influence of 131I biodistribution on the direct in-vivo counting measurements by a scanning whole-body counter with two NaI(Tl) detectors was evaluated by a Monte Carlo simulation. The peak efficiency for gamma rays from 131I was calculated for the Bottle-Manikin Absorption (BOMAB) phantom and International Commission on Radiological Protection voxel phantom with a uniform radionuclide distribution in the body and a localized distribution in the thyroid. The ratio of scan peak efficiencies for the BOMAB phantom with the uniform and localized distribution was 1.17 (localized/uniform), while that for the voxel phantom was 1.00. For the voxel phantom, a shielding by the head and tissues covering thyroid reduced the scan peak efficiency for the localized source, resulting in a negligible difference in peak efficiency between the source distributions. The assumption of a completely localized thyroid source is suggested to result in an underestimation within approximately 4% in residual activity assessment, considering 131I biodistribution calculated using ratios of physicochemical forms reported after the FDNPP accident, which represents a scenario with the maximum uncertainty. Consequently, the influence of 131I biodistribution on the scanning whole-body counting was negligibly small under the present conditions, partly due to the detector arrangement with two NaI(Tl) detectors positioned above and below the subject.
In this study, soil cores (0-20 cm) were collected at 45 sites located within a 30-km radius zone around the Belarusian nuclear power plant (BelNPP) in 2019 before its commissioning. Activity of gamma-emitting radionucli...In this study, soil cores (0-20 cm) were collected at 45 sites located within a 30-km radius zone around the Belarusian nuclear power plant (BelNPP) in 2019 before its commissioning. Activity of gamma-emitting radionuclides was measured in the samples using HPGe detectors. The study revealed low levels of 137Cs in the soil: the weighted average dry weight (d.w.) activity concentration (ACw) varied from 1.13 to 8.71 Bq/kg (d.w.). The ACw of natural radionuclides ranged: for 226Ra from 7.8 to 30.8 Bq/kg (d.w.), for 232Th from 10.9 to 33.0 Bq/kg (d.w.), and for 40K from 376 to 789 Bq/kg (d.w.). A good agreement between the ambient dose equivalent rate (ADER) values calculated with the soil samples and the ADER values previously measured in situ at the same sites is observed. The sites characterized here now have established pre-operational levels of 137Cs, 226Ra, 232Th, and 40K in soil thus can be surveyed again in future environmental studies.
The study introduces novel passive-adaptive exoskeleton-supported radiation protection equipment (PAESRPE) designed to overcome the limitations of conventional radiation protection equipment (RPE). The PAESRPE employs an...The study introduces novel passive-adaptive exoskeleton-supported radiation protection equipment (PAESRPE) designed to overcome the limitations of conventional radiation protection equipment (RPE). The PAESRPE employs an exoskeleton to transfer the weight of the RPE to the ground, and is supported by a modular configuration that allows for the selective integration of γ-ray or neutron shielding components, or combined protection against both radiation types. The test results demonstrated that PAESRPE achieved a γ-ray shielding ratio of 35.4 ± 1.6% (60Co), representing ~27% improvement compared with conventional RPE (60Co, with a shielding ratio of 8.3 ± 0.4%). For neutron radiation, PAESRPE achieved a neutron shielding attenuation of 50.3 ± 3.8% (252Cf), effectively addressing the challenge of high-energy neutron shielding protection for the RPE. PAESRPE achieved a maximum perceived weight reduction of over 80%. Practical trials conducted during nuclear power plant overhaul operations showed that PAESRPE reduced personnel radiation exposure by 32%, effectively enhancing on-site dose-control capabilities.
In image-guided radiation therapy (IGRT), kV imaging is routinely used for patient positioning. However, repeated imaging can result in a significant cumulative dose. Ideally, dose measurements should be performed using...In image-guided radiation therapy (IGRT), kV imaging is routinely used for patient positioning. However, repeated imaging can result in a significant cumulative dose. Ideally, dose measurements should be performed using ionization chambers calibrated for kV energies, but many facilities only have chambers calibrated for MV energies. This study investigated whether ionization chambers calibrated for MV energies could accurately measure kV doses in IGRT. Several cylindrical chambers were evaluated. Cross-calibration was performed using a kV-calibrated reference chamber. Surface doses were measured under clinical conditions and compared with nanoDot dosemeters. MV-calibrated chambers showed good agreement with the kV-calibrated reference. The quality conversion factor for the kV energy range was determined for the Farmer chambers. The obtained value was 0.931 ± 0.008 (N = 90). The surface dose with farmer-type chambers demonstrated dose deviations within ±1% compared nanodot dosemeter. Our results demonstrate the magnitude of uncertainty that arises when a Farmer-type ionization chamber, calibrated based on the water absorbed dose in a 60Co beam, is used for kV energy range surface dose measurements with an onboard imaging system of a linac without applying an energy correction factor. With appropriate cross-calibration, MV-calibrated ionization chambers can be used for kV dose measurement in IGRT. This method allows accurate and practical dosimetry, enhancing clinical efficiency and patient safety.
The ISO 4037:2019 standard is the reference standard for dosimetry laboratories who wish to realize dosimetric operational quantities for radiation protection calibrations. In implementing the ISO 4037:2019 standard, the...The ISO 4037:2019 standard is the reference standard for dosimetry laboratories who wish to realize dosimetric operational quantities for radiation protection calibrations. In implementing the ISO 4037:2019 standard, the X-ray radiation qualities need to be defined according to strict requirements on the material and thickness of the additional filtration, and according to metrologically traceable high voltage bias applied to the X-ray tube. This enables usage of standardized conversion coefficient from air kerma to operational quantities. However, the tube potential may vary as a function of tube current if a protective resistor is built into the protective tube housing, which, if not corrected, alters the energy distributions of the reference field and thus the value of the appropriate conversion coefficients. Particularly at low energies, the energy dependence of the conversion coefficients can be sharp and, depending on the specific realization of a radiation quality, the conversion coefficient from air kerma to dose equivalent can vary substantially. We have investigated the correspondence between the tube voltage measurements of a X-ray system based on calibrated voltage dividers and that of an X-ray spectrometer system based on a Cadmium Telluride (CdTe) detector in order to obtain an estimation of the resistance of the protective resistor that is usually unknown. A method based on X-ray spectrometry for calibration of the tube potential even in the presence of tube with protective resistor is presented. Finally, conversion coefficients were calculated using simulated spectra to study the influence of the protective resistor on the determination of these coefficients. The simulated spectra obtained from X-ray tube with and without a protective resistor resulted in differences in conversion coefficients mostly ˂2% but 5.6% for the radiation quality considered at the lowest energy.
Twenty-eight composite surface soil samples collected from four ecosystem types across El Kala National Park, Algeria - a United Nations Educational, Scientific and Cultural Organization (UNESCO) Biosphere Reserve. UNESC...Twenty-eight composite surface soil samples collected from four ecosystem types across El Kala National Park, Algeria - a United Nations Educational, Scientific and Cultural Organization (UNESCO) Biosphere Reserve. UNESCO Biosphere Reserve - were characterized for 40K, 137Cs, 226Ra, 228Ra, and 232Th by high-purity germanium (HPGe) gamma spectrometry. Mean activity concentrations were 178.7 ± 84.4 Bq kg-1 for 40K, 12.1 ± 9.7 Bq kg-1 for 137Cs, 112.1 ± 30.3 Bq kg-1 for 226Ra, and 25.4 ± 11.8 Bq kg-1 for 232Th-series (all uncertainties reported at coverage factor k = 2). Radium-226 concentrations exceeded the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) worldwide median of ~35 Bq kg-1 by a factor of ~3, reflecting geological enrichment within Tertiary phosphatic sedimentary formations of north-eastern Algeria. Potassium-40 and 232Th concentrations were within worldwide typical ranges; 137Cs was consistent with residual global fallout from mid-twentieth century atmospheric nuclear weapons testing. In-situ absorbed dose rates (park mean 83.8 nGy h-1) include a cosmic radiation contribution of ~35 nGy h-1 that is absent from terrestrial dose rates calculated using UNSCEAR (2000) conversion coefficients applied to site-specific data (park mean 74.8 nGy h-1. Subtracting the cosmic component yields a corrected terrestrial in-situ mean of ~49 nGy h-1 - ~35% below the calculated value - consistent with systematic overestimation by the UNSCEAR semi-infinite source geometry when applied to surface-concentrated (0-15 cm) radioactivity profiles. RESRAD-BIOTA Level 1 ecological screening, applying ICRP Publication 108 protective benchmarks of 10 mGy d-1 for terrestrial animals and 1 mGy d-1 for terrestrial plants, produced sum ratio factors (SRFs) of 0.0119 and 0.146, corresponding to safety margins of 84-fold and 6.8-fold below their respective benchmarks. Both SRF values were well below unity, confirming that Level 1 screening criteria are satisfied without requiring higher-tier assessment for terrestrial animals; a Level 2 assessment is recommended for terrestrial plants given the more constrained margin. Radium-226 dominated total biota dose (53% for animals; 75% for plants). These results establish the first systematic radiological baseline for this ecologically sensitive Mediterranean protected area and demonstrate the applicability of RESidual RADioactivity - BIOlogical Transport of Activity (RESRAD‑BIOTA) graded screening in naturally enriched geological settings.
Various methods of physical retrospective dosimetry based mainly on thermally and optically stimulated luminescence in daily-use items are employed to assess the dose after unplanned radiation exposure. The investigation...Various methods of physical retrospective dosimetry based mainly on thermally and optically stimulated luminescence in daily-use items are employed to assess the dose after unplanned radiation exposure. The investigations are usually performed in laboratory conditions, but the situation will differ in a real scenario. This was the motivation for the field test organized by European Radiation Dosimetry Group and Running the European Network of Biological and Retrospective Physical Dosimetry. The field test was arranged outdoors, where phantoms equipped with mobile phones, payment cards, pieces of dental ceramics and enamel, salty snacks and salt dosemeters, cigarettes and textile bags were irradiated. This manuscript presents doses estimated at National Radiation Protection Institute, as one of participating laboratories, using mobile phones and salt dosemeters in comparison with reference values. When using glass from the display, acceptable agreement was achieved for emergency dosimetry purposes. Resistors and salt measurements led to a more significant overestimation, in the case of resistors up to five times the reference value.
For in situ gamma-ray spectroscopy, a study was performed for characterization of a portable high-purity germanium (HPGe) detector utilizing four large-sized concrete pads, which were already used for the calibration of...For in situ gamma-ray spectroscopy, a study was performed for characterization of a portable high-purity germanium (HPGe) detector utilizing four large-sized concrete pads, which were already used for the calibration of airborne gamma-ray detectors. Each of the four concrete pads contains the known concentrations of 238U, 232Th, and 40K, including one so-called 'blank pad', which contains background activity. An efficiency transfer method has been adopted to calibrate the present HPGe detector using small-volume International Atomic Enery Agency (IAEA)-certified RGU-1, RGTh-1, and RGK-1 certified materials. To this end, each of four concrete calibration pads, having dimensions of (8 × 8 × 0.375) m, was marked by meshing into (1 × 1) m grids to enable determining activity in measurement positions. Then, the measurements were carried out in 49 positions on each calibration pad by using a 40% relative efficiency HPGe detector. The experimental efficiency values of this detector were also compared with Monte Carlo simulation results. As a result, the activity concentrations determined in this study showed good agreement with the declared activity values for 40K and 232Th contained in the calibration pads reported by MTA; however, the results for 238U exhibited a discrepancy of ~10% from the declared value. In order to demonstrate the applicability of the proposed calibration methodology in real environmental conditions, additional in situ measurements were carried out on the soil at the Sarayköy site of NÜKEN. The obtained activity concentrations were compared with those obtained from laboratory gamma spectrometric analyses for soil samples taken from the same locations. The study indicates that if large-sized calibration pads are used for the characterization of a portable in situ HPGe detector, thereby enabling accurate in situ gamma-ray spectrometric assessments.
Diagnostic reference levels (DRLs) are tools for optimizing medical exposures. We performed a retrospective analysis of 898 adult scintigraphic examinations acquired between 2018 and 2024 at a Peruvian hospital to establ...Diagnostic reference levels (DRLs) are tools for optimizing medical exposures. We performed a retrospective analysis of 898 adult scintigraphic examinations acquired between 2018 and 2024 at a Peruvian hospital to establish institutional DRLs for eight procedures. Typical values were defined as the median administered activity, and the 75th percentiles were used as institutional action levels to trigger protocol review. Median weight-normalized activities ranged from 0.1 MBq·kg-1 for 131I thyroid uptake testing to 14.5 MBq·kg-1 for three-phase bone scintigraphy; corresponding derived effective dose estimates were ~1-45 mSv and are reported only for population-level benchmarking. Comparison with international DRLs showed broad concordance; however, bone scintigraphy exceeded several reference values by >25%, indicating opportunities for optimization. These results provide the first institutional DRLs reported in Peru, identify priorities for local quality improvement, and support periodic review within an optimization cycle.
Typical values, as defined by the International Commission on Radiological Protection, support the optimization of protection in Computed Tomography (CT). They provide comparisons when new technologies are introduced, as...Typical values, as defined by the International Commission on Radiological Protection, support the optimization of protection in Computed Tomography (CT). They provide comparisons when new technologies are introduced, as well as for assessing the impact of factors such as the number of phases per examination, image-quality adjustments, and clinical-indication-based prescribing. This study assessed CT dose levels in a radiology department using a two-phase approach. Part I retrospectively assessed volume computed tomography dose index, dose length product, and size specific dose estimate values (2021-2022) across clinical indications and compared them with international Diagnostic Reference Levels. Protocol standardization, staff training, and optimization measures were implemented. Part II prospectively evaluated outcomes in 2024. Results showed that median dose values frequently exceeded international benchmarks and revealed variability in local practice. After optimization, most examinations demonstrated dose reductions of up to 61%, although some procedures remained ~20% above references. These findings highlight how multidisciplinary collaboration and staff education can strengthen radiation-protection culture and support clinically aligned imaging practice.
The exposure of the palm due to handheld wireless devices is analyzed using anatomical hand models of adults and children considering a frequency range from 900 MHz to 6000 MHz. The fingers of the hand models are articul...The exposure of the palm due to handheld wireless devices is analyzed using anatomical hand models of adults and children considering a frequency range from 900 MHz to 6000 MHz. The fingers of the hand models are articulated such that they hold the phone model in realistic positions. The antennas of the phone model are located in the microphone region, which maximizes the exposure of the palm. Approximately 140 configurations are evaluated numerically. The exposure is quantified in terms of the 10 g psSAR and compared with the psSAR calculated for a flat phantom. The results indicate that the exposure of the palm is within the extremity exposure limit of 4 W per kg in $\sim $96% of the cases for the hand models if the exposure limits are met for a flat phantom at 0 mm distance. The numerical uncertainty for the exposure evaluation is assessed as 24.7% ($k=2$).
This study aims to assess different advanced treatments modalities in terms of their toxicity NTCPs and the induced second primary cancers excess absolute risk (EARs) using in-house software "COUPOLE" in case of prostate...This study aims to assess different advanced treatments modalities in terms of their toxicity NTCPs and the induced second primary cancers excess absolute risk (EARs) using in-house software "COUPOLE" in case of prostate cancer. A total of 72 patients (GI, GII, GIII, and GIV) were treated using: VMAT1, VMAT2, HT and 3D-CRT. The treatment was planned with 6 MV using VARIAN HDX 2100C, VERSA HD Linear Accelerator, TOMOTHERAPY and ELEKTA Synergy. The prescribed dose was 76 Gy/2 Gy/F for GI and GII and 71.3 Gy/2.3 Gy/F for GIII and GIV. The Normal Tissue Complication Probability NTCPs (%) results for rectum = 9.5, 7.1, 5.18, and 22.46 for GI, GII, GIII, and GIV. The NTCP (%) for bladder = 0.05 for GI; 0.041 for GII; 0.0 and 1.67 for GIII and GIV. The EAR (/10000PY) for rectum and bladder are: 0.07(GII), 1.71(GIII), 1.60(GIV), and 6.30(GI), 0.01 (GII), 0.46(GIII), and 0.46(GIV), respectively. Minor toxicity for OARs when using HT but the risk is significant for bladder for HT and VMAT.
This study evaluates neutron and photon equivalent dose sensitivity in patient organs during prostate three-dimensional conformal radiotherapy (3DCRT) using Monte Carlo simulations. A validated Varian Clinac 2100C LINAC...This study evaluates neutron and photon equivalent dose sensitivity in patient organs during prostate three-dimensional conformal radiotherapy (3DCRT) using Monte Carlo simulations. A validated Varian Clinac 2100C LINAC model and a hybrid XCAT adult male phantom were used with an 18 MV photon beam. Component-wise sensitivity analysis showed that removal of the flattening filter caused the largest increase in neutron doses, with ratios of 1.49 in the testes, 1.39 in the bladder, and 1.38 in the colon, indicating a dominant shielding role. The primary collimator also showed significant shielding, with neutron dose ratios up to 1.29 in the rectum. Treatment room shielding contributed up to 61% of the neutron dose in the brain via room-return effects. Photon doses decreased with increasing distance from the field, highlighting spatial dependence and implications for radiological protection.
This paper presents a comprehensive safety analysis of the NuScale Small Modular Reactor, a next-generation nuclear technology. The NuScale design emphasizes enhanced safety, flexibility, and efficiency, achieved through...This paper presents a comprehensive safety analysis of the NuScale Small Modular Reactor, a next-generation nuclear technology. The NuScale design emphasizes enhanced safety, flexibility, and efficiency, achieved through a natural circulation cooling system and robust passive safety functions. The analysis is conducted using the RELAP5/SCDAPSIM3.4 system code for high-fidelity thermal-hydraulic simulations. The first part details the steady-state qualification of the reactor model, a crucial step to establish a reliable baseline for normal operation and subsequent accident analyses. The study confirms the model's accuracy against key design parameters including temperature distributions, coolant flow rates, and system pressure validating its predictive capability. Building upon this qualified model, the second part investigates a severe beyond-design-basis accident scenario. The initiating event is the inadvertent opening of one Reactor Vent Valve, leading to an inside containment Small Break Loss of Coolant Accident. This breach is compounded by the postulated total failure of both the Emergency Core Cooling System and the Decay Heat Removal System, creating a fully unmitigated scenario. The progression of this severe accident, simulated for a duration of 500 s, critically assesses the reactor's passive safety features and inherent resilience. The system's response is analyzed in detail, with key findings showing a consistent behavior comparable to the results of similar scenarios documented in the literature.
The present study focuses on the effect of the gamma irradiation dose on the adsorption kinetics of Rovamycin by composite materials. The retention of this antibiotic is closely related to this parameter. The equilibrium...The present study focuses on the effect of the gamma irradiation dose on the adsorption kinetics of Rovamycin by composite materials. The retention of this antibiotic is closely related to this parameter. The equilibrium plateau begins to appear around 270 min. The equilibrium time with the macrolitic solution for all adsorbent beads is 360 min to ensure reaching equilibrium, and the maximum adsorption capacity is 19 mg/g. In addition, the adsorption obeys the pseudo-first-order kinetics for the bioadsorbent prepared based on orange peel powder (OPP) irradiated at 4 kGy and the intra-particle diffusion model for those prepared based on OPP irradiated at 1, 2, and 3 kGy.
Radioiodine-131 (131I) is the most significant environmental contaminant during a short-term nuclear accident. When present in the atmosphere, it concentrates mainly in the thyroid gland through inhalation or ingestion....Radioiodine-131 (131I) is the most significant environmental contaminant during a short-term nuclear accident. When present in the atmosphere, it concentrates mainly in the thyroid gland through inhalation or ingestion. This can lead to partial or total destruction of thyroid cells, potentially causing hypothyroidism. It therefore negatively affects the thyroid in exposed populations. At high doses, radiation can also cause cellular mutations and increase the risk of thyroid cancer, particularly in children under five years old and those exposed during pregnancy. In such cases, nonradioactive iodine tablets are used to saturate the thyroid and block the absorption of radioactive iodine. This study aimed to quantify and compare total atmospheric emissions of 131I using the ORIGEN-JR code, and to assess the radiological impacts on the environment and humans by estimating and comparing the total effective dose (TED) and committed effective dose equivalent (CEDE) using the HOTSPOT code in the early stages following the Fukushima accident and at the TRIGA Mark-II research reactor in Bangladesh. The simulation results indicate that for the TRIGA MARK-II research reactor, the TED was approximately 379 mSv at a distance of 360 m, with a thyroid CEDE of 19 mSv. For the Fukushima reactor, the TED was approximately 875 mSv at 590 m, with a thyroid CEDE of about 63 mSv. Compared to the IAEA's annual regulatory limits, the TED and CEDE resulting from the Fukushima accident exceeded the permissible thresholds, requiring both evacuation of the population and iodine prophylaxis. Conversely, for the TRIGA MARK-II research reactor, the distribution of iodine tablets is not necessary; however, containment measures remain essential.