Radiation protection dosimetry最新文献

In this paper, neutron shields based on hydraulic lime-based brick samples were fabricated by adding various mass additive materials in proportions such as lime (CaCO3), titanium oxide (TiO2), hematite (Fe2O3), aluminum oxide (Al2O3), calcium sulfate (CaSO4), silicon dioxide (SiO2), and boron carbide (B4C). Neutron attenuation factors such as neutron transmission factor, half-value layer, effective removal cross-section ΣR (cm-1), mean free path, and neutron flux were determined theoretically using Monte Carlo simulation GEANT4 and Fluka codes. Fast neutron absorption dose rate experiments were performed using a 241Am-Be source and a BF3 gaseous proportional detector. In addition, the absorbed dose values were theoretically determined using the Fluka code. All the obtained data were compared with the results of the examined reference samples (conventional concrete, some heavy concretes, and paraffin). All new brick materials were detected to have superior shielding capacities compared to the reference material. The proposed brick samples can be used as an alternative radiation protection material for regular shielding materials.

Radiation exposure risk to the lens of the eye varies based on where technologists assist during chest X-rays. In this study five radiologic technologists participated in the training for lens exposure reduction methods proposed in previous studies, and the personal dose equivalent at a depth of 3 mm [Hp(3)] near the eyes were evaluated. Data were collected before and after the training. After the training, three radiologic technologists had 3%-27% decreases in Hp(3) at the measurement points, and the proportion of selecting the assistance position with the lowest Hp(3) increased. However, one technologist with extensive experience in chest X-ray examinations showed no significant differences in Hp(3) before and after the training. This suggests that the training is specifically effective for technologists with less experience in radiation-related work because the radiation protection education brought about behavioral changes in the radiologic technologists, leading to a reduction in their Hp(3).

Evaluation of radiological dose rate to aquatic non-human biota available at Kakrapar Atomic Power Station site, Gujarat, India has been carried out using Environmental Risks from Ionizing Contaminants: Assessment and Management tool. Radiological dose rate to five different varieties, each of fresh water weed and fish, were studied. Radiological dose rate (μGy.h-1) for aquatic weed and fish was found to be in the range of 5.2E-05 to 1.9E-03 and 1.1E-05 to 1.6E-03, respectively. Radiological dose rate for aquatic weed and fresh water fish available at Kakrapar Gujarat site was compared with worldwide reported values. The total dose rate for each organism is well within the screening dose rate criteria of 10 μGy.h-1. The Risk Quotients are calculated and found to be less than unity in all the cases. This indicates that the radiation exposure levels in the area are low and that the non-human biota at Kakrapar Gujarat site, India are not exposed to any statistically significant reactor released radionuclides.

This study evaluates the occupational equivalent doses to selected organs and tissues received by veterinary staff at the Veterinary Clinical Hospital of the University of Extremadura, where $sim $7000 diagnostic imaging procedures (X-ray and computed tomography scans) are performed annually on patients of various sizes. Experiments were conducted with dosemeters positioned to simulate typical locations of veterinary operators during radiographic procedures under clinical conditions. Canine cadavers and equine anatomical specimens were used as animal patients, and scattered radiation exposure was measured at operator-relevant sites-including the hands, thorax, gonads, and eyes-both with and without protective equipment. The findings confirm that, with proper radioprotection measures, doses remain well below the legal limit (500, 50 and 20 mSv y$^{-1}$ for hands, eye lens and other tissues, respectively), even in worst-case scenarios-particularly during portable equine radiography exposure. However, it highlights the need for strict adherence to radiation safety protocols.

The present study focuses on the measurements of specific activity levels of 14C in the atmospheric CO2 using the passive sampling technique coupled with benzene synthesis method. The purity of benzene, synthesized from atmospheric CO2 was measured using the gas chromatography technique, and it was found that the purity of benzene was 99%. The Liquid scintillation counter was calibrated with a benzene sample synthesized from the NIST Oxalic acid standard, and the efficiency of the system is found to be 70.2% ± 0.8%. The passive sampling method was used to sample the atmospheric CO2. The atmospheric CO2 absorbed in 2N sodium hydroxide (NaOH) solution. The average amount of carbon absorbed in 2N NaOH solution is 5.27 ± 0.20 g for the sampling duration of 7 days. The measured specific activity 14C levels in the atmospheric CO2 varied from 240.9 to 250.0 Bq/kg C with an average specific activity of 246.3 ± 2.5 Bq/kg C.

This study investigates the contamination of sweet potatoes by 137Cs following a hypothetical radiological dispersion event, assessing its implications for food safety and public health. Given the increasing concerns about nuclear energy expansion, this research is particularly relevant to agricultural systems, which are crucial to food security. Using HotSpot Health Physics Codes (v3.1.2), we simulated the radionuclide dispersion in a sweet potato farming area, considering environmental factors like atmospheric stability and soil properties. The model assesses the transfer of radioactive material to crops and the potential health risks to consumers. The evaluation links 137Cs exposure to an increased risk of leukemia, represented by the excess risk of its fatal occurrence over a lifetime, emphasizing the need for post-radiological incident monitoring. The results of the simulations suggest, for example, that the concentration of activity of 137Cs in the root of the sweet potato can vary by up to 3 orders of magnitude for the same location, depending on variations in the local atmospheric stability classes. Such sensitivity was also observed for the risk of developing radiation-induced leukemia, whose average values for the adopted radionuclide-to-plant Transfer Factors models may differ by up to 2 orders of magnitude depending on the same variables. Through computational modeling, this study offers insights into the threat posed by radiological contaminants in food chains and underscores the importance of surveillance measures in protecting public health.

This study investigates and analyzes the abnormal results of personal dose monitoring among radiation workers in Chongqing from 2021 to 2024, aiming to provide a scientific basis for occupational health management and radiation protection practices. The Registration Form for Investigation of Occupational External Exposure Individual Monitoring Doses was issued to individuals whose single monitoring results exceeded the investigation level. Detailed investigations were conducted to identify the causes of abnormal doses, including on-site radiation protection testing when necessary. From 2021 to 2024, a total of 1043 abnormal personal doses were recorded among 182 014 monitoring instances, yielding an abnormal rate of 0.57%. Diagnostic radiology and interventional radiology workers accounted for the majority of cases, at 64.43% and 22.53%, respectively. Most abnormal doses were below 5 mSv (72.48%). The primary causes included improper dosemeter usage (75.74%), increased workload (14.29%), and unidentified reasons (9.97%). The actual exposure rate was significantly higher among interventional radiology workers (47.66%) and those in tertiary hospitals (28.67%). Strengthening radiation protection training, improving dosemeter usage compliance, and optimizing workload management are essential to reduce abnormal doses. Special attention should be given to interventional radiology workers and tertiary hospital staff to mitigate occupational radiation risks.

Volumetric modulated arc therapy for pediatric medulloblastoma improves target precision but increases low-dose exposure to healthy tissues, elevating secondary cancer risks. This study evaluates treatment planning system (TPS) accuracy for out-of-field dose (OOFD) predictions by performing measurements with optically stimulated luminescence dosemeters (OSLDs) in an anthropomorphic phantom. TPS predictions were accurate near the field (<3% at 5.5 cm) but significantly underestimated doses at larger distances, with discrepancies ranging from 16% (thyroid) to 64% (heart). These findings highlight TPS limitations in modeling peripheral leakage and scatter and underscore the critical role of OSLD-based monitoring for pediatric patients. Accurate OOFD verification is essential for risk assessment and long-term safety. Future work should focus on refining TPS algorithms and integrating direct dosimetry into clinical practice for this vulnerable population.

This study provides an evaluation of public health and economic impacts following a hypothetical nuclear accident. Using the Pasquill-Gifford (PG) atmospheric stability classification, simulations were conducted with HotSpot Health Physics to determine the total effective dose equivalent (TEDE) and associated excess relative risk (ERR) for radiation-induced leukemia. Risk estimates were obtained through the biological effects of ionizing radiation V and VII radioepidemiological models, considering age- and sex-specific vulnerability across various exposure zones. The Geographic Information Systems (GISs), combined with demographic data, enabled stratified analysis. The results reveal differences in exposure and risk patterns that are influenced by environmental conditions, demography, and atmospheric stability. Furthermore, this study introduces a cost-assessment approach based on ERR-adjusted radiation dose distributions, offering a conservative perspective on the economic impact of radiological health effects. The work also emphasizes the significance of demographic sensitivity and conservative latency assumptions in fostering resilient medium-term public health strategies.