Journal of Radiological Protection最新文献

Combined chest and abdomen computed tomography (CT) in paediatric trauma patients is rare and typically reserved for severely injured patients due to concerns about the potential radiation risks associated with CT in children. This study aims to analyse the radiation exposure of chest and abdomen CT in paediatric patients following trauma resuscitation. A retrospective single-centre study was conducted on patients aged 0-<15 years who underwent CT in the trauma resuscitation unit between 04/2020 and 08/2023. Patients were categorised into three age groups (AGs) (I: 0-<5years, II: 5-<10 years, III: 10-<15 years) and radiation exposure parameters were analysed age-stratified. Effective dose (ED) was calculated using conversion factors and organ doses were determined through Monte Carlo simulations. Out of 212 paediatric patients, 62.7% (133/212) received a CT scan, with 60.2% (80/133) undergoing combined chest and abdomen CT. In 70.0% (56/80), the standard protocol was applied, complete dose data available, and these were included in the dose calculation (median age: 6.2 years; IQR: 3.9-10.5 years; 37.5% female). Radiation exposure was as follows (median [IQR] CTDIvol, DLP, ED): chest: I: 0.7 mGy (0.5-0.8), 13 mGycm (10-16), 2.1 mSv (1.6-2.4); II: 1.4 mGy (1.1-1.9), 35 mGycm (25-49), 3.7 mSv (2.7-5.2); III: 2.7 mGy (2.2-3.2), 76 mGycm (66-95), 4.3 mSv (3.7-5.3); abdomen: I: 0.8 mGy (0.6-0.9), 24 mGycm (20-29), 2.0 mSv (1.6-2.5); II: 1.6 mGy (1.1-1.9), 60 mGycm (41-77), 3.2 mSv (2.2-4.2); III: 3.1 mGy (2.4-3.9), 143 mGycm (101-179), 4.3 mSv (3.0-5.4). In the organ dose analysis, the genital organs were particularly affected by increased radiation exposure. 16.1% (9/56) of patients were not scanned using age-adapted protocols. Chest and abdomen CT in paediatric trauma patients can be performed with moderate radiation exposure. Nonetheless, non-adherence to age-adapted protocols highlights the need for improved compliance to ensure optimal radiation safety in paediatric trauma imaging.

Software to fit complex models using big data sets is needed to answer persistent and emerging questions in radiation epidemiology. The open-source R package Colossus was developed to meet this need. Colossus was designed to take advantage of the input and graphing flexibility of R scripts, employ multi-core systems to run analyses faster, and permit the straightforward addition of future capabilities. Incorporating methods to propagate covariate uncertainty into model parameter uncertainty is the next major focus area. Through guidance from NCRP Commentary 34, methods of analysing multiple realisations of exposure were implemented in Colossus. Frequentist model averaging and Monte Carlo maximum likelihood programs were added to Colossus to provide different methods of applying complex risk models to datasets with intricate exposure uncertainties.

The article presents a targeted remediation system for 71 rural settlements in five southwestern districts of the Bryansk region, Russia, affected by the Chernobyl accident. The most effective technologies for reducing radiation doses for residents of rural settlements are considered. Remediation strategies have been developed by assessing the current radiation levels, demographic conditions, and economic land use, while optimising the use of seven technologies. This process relies on computer geographic information systems for decision support, specifically ReSCA and GIDSS. Two approaches to restoring rural settlements are presented, focusing on either economic costs or social acceptability. For each settlement, we identified the most effective targeted remediation measures by considering radiological indicators, associated costs, and the social acceptability of the technologies involved. The estimated cost of implementing remediation technologies to reduce radiation exposure of the population is between €12.3 million and €13.3 million. The implemented remediation strategies could reduce the collective radiation dose to the population by 79-88 man-Sv, with an average cost of 151-156 thousand €/man-Sv. Over the last 15-20 years, the expenses associated with settlement remediation have surged by 4.7 times, while the potential savings in collective radiation exposure for residents have decreased by 35%. Research indicates that the most impactful strategies involve utilising ferrocene for livestock and the surface improvement of grassland in inhabited areas. The radiological and economic efficiency of the radical improvement of hayfields and pastures has sharply decreased compared to the early 2000s due to high costs of its implementation. In 16 settlements, using all effective remediation technologies will not decrease the population's total radiation dose below 1 mSv a^-1. At the same time, the reduction factor for the total radiation dose experienced by residents in the most vulnerable settlements is expected to range from 1.7 to 2.2 times.

This study presents the development and field validation of a UAV-based airborne gamma-ray spectrometry system (MARK-M1), designed by the Korea Atomic Energy Research Institute for rapid radiological assessment in post-accident scenarios. The MARK-M1 integrates two LaBr₃(Ce) detectors, global positioning system, and a laser altimeter, with data transmission ensured via Bluetooth communication. Field surveys were conducted in collaboration with the Japan Atomic Energy Agency around the Fukushima Daiichi Nuclear Power Plant. An attenuation correction factor was derived from hovering flights at multiple altitudes and applied to convert aerial measurements to dose rates at 1 m above ground level. The results showed that flight speed had little effect on dose rate estimation when appropriate detector sensitivity and flight line spacing were ensured. However, in low-lying areas with sloped terrain, significant discrepancies were observed between airborne and ground-based measurements, indicating the limitations of flat-ground assumptions in attenuation models. Incorporating terrain data such as digital elevation models is suggested to improve estimation accuracy in complex topographies. These findings demonstrate both the practical utility and necessary refinements for UAV-based gamma-ray surveys in real-world emergency response applications.

The goal of this research is to create a computational dosimetry system to monitor the dose received by nuclear medicine workers on their extremities. The system creates multiple Monte Carlo simulations to assess the dose received in different sections of the hands. Each simulation is created based on depth camera images of the manipulation of radioactive sources, using digital twins to represent the hands of the worker and the radiation source. The position of the hands and the source is constantly recalculated using computer vision algorithms. In this paper, we explain the different components of the computational system, assessing the possible sources of uncertainty introduced by each component. As a proof of concept, we compared the dose estimated by the computational system with real dosimeter measurements for two different scenarios. The simulated dose was, on average, 51% of the measured dose.

The accurate reconstruction of external photon doses is essential for credible radiation epidemiology. This article presents the methodology used to derive dose estimates for 37 012 Hanford Site workers included in the Million Person Study. The approach employs historical dose records from the Hanford Radiation Exposure database and a previous epidemiology study. Bias correction factors specific to dosimeter type and period of use were applied and missing annual doses were estimated using a hierarchical nearby method to estimate deep dose equivalent for each worker. For early years with limited detection sensitivity, missed doses were quantified based on expected time-period-specific, low-dose statistical distributions. The revised dose estimates resulted in lower median and mean career doses than unadjusted data, while increasing the number of person-years with nonzero dose. Sensitivity analyses assessed the influence of bias in dosimetry measurements, missed doses and gap years on dose estimates. Differences in cumulative dose estimates between unadjusted and revised annual estimates are most prominent in the early operational years due to the highest bias during that time period.

Monte Carlo (MC) simulations are considered the gold standard for calculating radiation dose in complex radiation fields. However, these simulations often require substantial computational resources. Based on our team's existing graphics processing unit (GPU) modules for photons and electrons/positrons, this research developed neutron GPU physics modules including elastic scattering, inelastic scattering, radiative capture, and fission. These were integrated into the Neudep (GPU-based NEUtron-photon-electron/positron coupled Dose Estimation Program). This program enables coupled multi-particle transport of neutrons, photons, and electrons/positrons across broad energy ranges and incorporates comprehensive physics for all particle interactions. During neutron interactions, photons and secondary neutrons are produced. These photons undergo various physical processes: the photoelectric effect, Compton scattering, and pair production, generating photoelectrons, Compton electrons, and recoil electron-positron pairs, respectively. The associated electron interactions include bremsstrahlung, ionisation, and multiple scattering. Bremsstrahlung, in particular, gives rise to secondary photons. Additionally, positron annihilation results in the production of secondary photons. All these secondary particles are stored in a memory stack and are transported only after the primary neutron transport process is completed. The Neudep program was validated for accuracy and tested for computational efficiency using both a homogeneous Water Phantom and the Chinese adult male voxel model (CRAM). The results indicate that the energy deposition discrepancies between Neudep and the reference MC code are less than 2%, with neutron incident energies of 3 MeV showing deviations of less than 0.5%. Organ dose differences generally remain within 5%. While maintaining computational accuracy, the Neudep program efficiently simulates 1 million neutrons in just 2 s. Additionally, the transport time for 10 million neutrons through a complex human model can be reduced to under 1 min. Neudep can reduce computation times by 78-5000 times compared to traditional central processing unit-based MC software. This tool demonstrates tremendous potential for rapid and accurate dose calculations.

As highlighted in the Ukrainian Regulatory Threat Assessment Report for 2017, a strong physical protection regime ensuring the state regulation of physical protection in Ukraine has been established. However, significant gaps in nuclear security regulations still exist and pose a substantial threat. Therefore, the international technical assistance project intended to identify areas to improve the regulatory framework for nuclear security was implemented and resulted in a list of primary nuclear security regulations to be developed. The successful implementation of the project for the development of the first priority item on this list-General Nuclear Security Provisions-enables the implementation of the International Atomic Energy Agency nuclear security fundamentals into Ukrainian practices and opens the way for the development of subsequent nuclear security regulations. However, the Russian invasion, especially the seizure of the Chornobyl and Zaporizhzhia nuclear power plants, revealed new threats and requirements for nuclear security, which are also addressed in this article.