Journal of Radiological Protection最新文献

Radiation exposure to the fingers of clinicians carrying out radiosynoviorthesis with yttrium citrate (⁹⁰Y) can be an area of concern if equipment or practice is sub-optimal, with contact dose rates in the mSv·s^-1range around the syringe and needle neck. Syringe shields reduce potential exposure around the syringe but offer no protection around the needle neck. There are no commercially available protection products in the United Kingdom to address this deficiency. Clinical safety requires that the clinician is able to feel the position of the needle and limit the amount of needle movement at critical times. Although direct handling of the needle neck presents the easiest solution, radiation protection concerns make this unacceptable, and leave forceps the only established alternative to minimise finger doses. We present a further method to address these issues-a locally designed infection control compliant finger protection ring which has been 3D printed and used at the authors' hospital. Potential extremity doses have been measured for three methods. 1, direct finger contact with the needle neck, 2, forceps, and 3, use of a 3D printed ring. Finger dose coefficients with the first method (direct contact) have been demonstrated experimentally to be as high as 33µSv·MBq^-1, with even higher results recorded in clinical practice at 79.5µSv·MBq^-1. The second method (forceps) reduces the potential skin dose coefficient to less than 1µSv·MBq^-1. The third method (finger protection ring) achieves a similar dose coefficient to forceps. Forceps are more technically demanding for the clinician. This new finger protection ring ensures that patient safety is maintained, the procedure is technically easier for the clinician, finger doses are as low as Reasonably Practicable, and contamination risk is reduced.

Breast tissue is highly sensitive to ionising radiation, making dose management in mammography crucial to reducing the risk of radiation-induced cancer. Dose optimisation, guided by the as low as reasonably achievable principle, aims to minimise exposure while maintaining diagnostic quality. This study focuses on establishing national diagnostic reference levels (NDRLs) for digital mammography (DM) in Nepal to support dose optimisation efforts. A retrospective analysis was conducted using data from 786 patients across six hospitals equipped with DM systems. Both symptomatic and screening mammograms in cranial-caudal (CC) and mediolateral oblique (MLO) views were included for both breasts. Mean glandular dose and entrance skin dose were extracted from Digital Imaging and Communication in Medicine headers. For each mammogram view, data from a minimum of 50 patients were analysed. Technical parameters such as tube voltage (kVp), tube current (mAs), compression force (CF), and compressed breast thickness (CBT) were also documented. The established NDRLs for DM are 1.03 mGy for CC and 1.17 mGy for MLO views. The mean CBT and CF are 56 ± 13 mm and 122 ± 29 N, respectively. Comparisons with other countries highlight the potential for further dose optimisation to maintain diagnostically adequate images at lower exposure levels. Implementing such strategies can reduce patient radiation dose in DM without compromising diagnostic performance.

Boundary-representation (B-Rep) computational phantoms (CPs) offer high flexibility and anatomical accuracy, making them valuable tools in dosimetry and medical imaging simulations. However, their complexity and the need for expertise in graphic modelling limit their accessibility and adoption. Moreover, most Monte Carlo (MC) particle transport codes lack native support for B-Rep geometries, requiring complex and non-automated conversion to compatible formats, further complicating their use. To address these challenges, we developed the interactive posture program (IPP), a software platform to ease the use of B-Rep phantoms. The IPP features a real-time three-dimensional (3D) graphical interface, allowing users to easily create individualised phantoms and realistic exposure scenarios. Currently, the IPP includes three flexible phantoms-Adult Male, Adult Female, and 1-year-old Female-from the realistic anthropomorphic flexible (RAF) family, which can be extensively customised using integrated morphing tools to simulate diverse anatomical variations. Additionally, the IPP provides a comprehensive library of predefined exposure scenarios and advanced geometry creation tools, which allow the creation of accurate and individualised simulations. Finally, the IPP automatically generates simulation input files compatible with the most widely used MC transport codes, significantly simplifying the use of B-Rep phantoms within dosimetry and imaging simulations.

The International Commission of Radiological Protection (ICRP) has made a review of the system of radiological protection toward a revision of general recommendations. The management of tissue reactions, previously known as deterministic effects, has always been a core aspect of the system of radiological protection. It is directly related to the health objectives of the system, which aims to prevent such effects. Tissue reactions, currently defined as 'injury in populations of cells characterised by a threshold dose and an increase in the severity of the reaction as the dose is increased further', are, in theory, prevented when dose remains below the threshold. This has significant implications for the system, including in relation to the setting of individual dose limits. This article reviews and discusses the approach proposed by the Commission with regards to the management of tissue reactions. It is based on the review of a set of relevant ICRP Publications, with the aim of contributing to the ongoing work on the review of the system of radiological protection.

The 2022 radiation survey campaign in the Kyiv region aimed to assess radiation levels in areas previously occupied by Russian troops, focusing on territories where contamination might be suspected due to military activity in the Chornobyl exclusion zone. The planning and execution of radiation survey in areas affected by military occupation required careful consideration of numerous factors, including access restrictions, potential contamination, and the safety of personnel and residents. While some of the challenges and difficulties were overcome in the course of the radiation survey, the others could not be addressed immediately. All the lessons learned, measures taken, problems encountered and possible solutions are shared in this paper as recommendations for organisational, instrumental, personnel and communication aspects to be considered during the future surveys in further liberated territories. In cases where facilities are severely damaged, a conservative approach should be adopted, assuming the loss or damage of radiation sources unless proven otherwise. The use of robust and reliable measurement equipment is essential. Additionally, teams should be trained to handle the specific hazards of conflict zones, including mine safety, trauma care, and navigating challenging terrain. The psychological resilience of team members is crucial, as exposure to traumatic evidence of violence may impact their capabilities. The survey methodology should prioritisein situmeasurements over sample collection, given the probable logistical challenges of transporting samples to the laboratory. For food and water sampling, this should only be carried out in cases of immediate contamination risk. Finally, transparent communication with the public and relevant stakeholders is essential. The survey results should be shared openly to reduce public concerns and ensure trust in the safety measures taken. Communication campaigns should be based on reliable, fact-based information, emphasizing the credibility of survey results, and fostering cooperation between different stakeholders involved in radiation safety. The major limitation for providing recommendations on radiation surveys in the territories affected by the hostile military occupation of Ukrainian territory is a great uncertainty about when and how exactly the temporarily occupied territories of Ukraine will be liberated, and what social and economic situation will be in these territories.

This study aimed to propose and validate optimal weighting factors for weighted computed tomography dose index (CTDI_w) in dual-energy computed tomography (DECT) to improve average dose estimation in the central cross-sectional plane of a CTDI phantom. CTDI₁₀₀measurements were acquired at 13 points in a CTDI phantom with a diameter of 32 cm using five dual-energy tube voltage combinations ranging from 70/Sn150 to 100/Sn150 kV. The average doses across the cross-sectional plane were calculated by integrating the dose profiles. After calculating the average dose profiles, the weighting factors were optimised using a Python-based search algorithm to minimise the relative error to within 1%, while selecting the smallest possible integers to maintain accuracy and simplicity. The percentage difference (PD) between the average dose and the CTDI_wwas then evaluated for the proposed weighting factors and those derived from two previously reported methods. The proposed weighting factors were derived as 2/5 for the centre and 3/5 for the periphery. Applying these factors reduced the PD between the CTDI_wand the average cross-sectional dose to a maximum of 0.5%. Compared with the currently used standard weighting factors and two previously reported weighting factors, the proposed factors provided the most accurate estimation of the average dose in the CTDI phantom across all tube voltages in DECT, with a maximum deviation of only 0.5%. In contrast, previously reported factors showed deviations of up to 2.5%. These findings demonstrated that the proposed weighting factors provided a more accurate estimation of CTDI_wunder DECT compared with both the currently used and previously reported factors.

This study aims to evaluate a realistic scenario to provide deeper insight into potential future events, necessitating a well-prepared and public-supported emergency response to improve resilience against radiological threats and mitigate their impact on public health and safety. The use of a radioactive dispersal device (RDD) in urban areas in Stockholm, Sweden, was simulated using the decision support system LASAIRs (Lagrange Simulation of the Dispersion and Inhalation of Radionuclides). The findings confirm that the urban landscape will influence the distribution of radioactive materials, especially in adjacent areas where the distribution is strongly dependent on the influence of adjacent buildings and other large structures, the surface structures and the presence of strong winds in open fields. The results suggest that radiation concentrations will be dispersed over a local area, with a predicted maximum dose directly associated with the source term input.

Epidural blocks are commonly performed interventional pain procedures under C-arm fluoroscopic guidance. However, radiation exposure to the ocular lens remains a significant concern due to its high radiosensitivity and the associated risk of radiation-induced cataract formation. Therefore, this study aims to quantify ocular lens dose during cervical and lumbar epidural blocks (CEBs and LEBs), and to evaluate the shielding efficacy of 0.5 mmPb lead-free radiation-protective eyewear (R-PEW), using a quantitative, phantom-based experimental design that simulates realistic clinical scenarios based on exposure conditions derived from 150 real patients. An adult anthropomorphic phantom was used, and ocular lens doses were recorded with optically stimulated luminescence dosimeters under six experimental conditions defined based on procedure type, patient position, and eyewear status. Without shielding, the maximum lens dose was 1.90 mSv during prone CEBs, while the greatest reduction with R-PEW was 83.3% during prone LEBs. Dose asymmetry between the right and left eyes corresponded to differences in source-to-eye distance. All measured doses were substantially below the cataract threshold (0.5 Gy) and the International Commission on Radiological Protection annual public equivalent dose limit for the lens of the eye (15 mSv). Nonetheless, R-PEW consistently reduced exposure under all conditions, offering additional protection in accordance with the optimisation principle. These findings suggest that, although routine patient shielding is not warranted given the low absolute doses, R-PEW represents a simple and effective adjunct to further minimise ocular exposure during C-arm-guided epidural blocks.

The International Commission on Radiation Units and Measurements (ICRU) in the ICRU report 95 defined a new set of operational quantities for radiation protection. These quantities replace the operational quantities defined in ICRU Report 39/51 used for measuring personal and area monitoring. Since 2022, the impact has been accessed for various types of monitoring systems. For individual monitoring of whole-body doses of photons, the use of the ICRU 95 quantities, theH_P, result in an overestimation of radiation doses of up to 5 times for low energy photons, directly impacting doses measured in medical applications. Currently, it has not been demonstrated that single-element or double-element dosimeters using different filters over the sensitive elements are able to measureH_P. Therefore, this work investigates if it is feasible for a new type of all-optically stimulated luminescence (OSL) dosimetry system, composed of two OSL materials, magnesium tetraborate doped with cerium, lithium and gadolinium (MgB₄O₇:Ce,Li,Gd) and beryllium oxide (BeO), to measure ICRU 95 operational quantities for photons. The results demonstrate that the useful range for energy discrimination from the tandem curves starts at higher energies (83 keV). Therefore, the tandem method applied to doped-MgB₄O₇and BeO is limited to the identification of low/high average energy and cannot be used to correct the low energy dependence observed in the ICRU 95 operational quantities for photons.

Epidemiological studies of large groups of nuclear industry workers offer a significant opportunity to increase our understanding of the long-term effects on health of the protracted accumulation of dose received at a low dose rate from many discrete exposures to ionising radiation. The effects of such extended aggregation of doses form an important part of the everyday concerns of radiological protection against low-level exposures. For more than half a century, databases of nuclear workers have been assembled, and the numbers of workers currently included in studies, together with the numbers of deaths among them that have now occurred, are capable of generating reasonably precise risk estimates that should provide meaningful comparisons with those obtained from other studies, such as of the Japanese atomic bomb survivors. However, constructing, updating and maintaining these large databases, linking workers to occupational dose databases and to registers of deaths (and other outcomes, such as incident cancers) and their causes, and analyses of these data that endeavour to take account of other influential factors (such as smoking) are far from straightforward. A critical review of recent nuclear worker studies illustrates the difficulties in reliably interpreting reported statistical associations between rates of cancer and cumulative occupational doses because of the real possibility of distortions produced by biases, confounding and/or the interplay of radiation with other risk factors. This does not mean that studies of nuclear workers should be abandoned, far from it, but it does mean that appropriate effort needs to be expended on these studies before confident conclusions about the levels of risks from radiation exposure can be drawn from them. Unexpected findings should be examined in depth to gain a proper understanding of their origin, including the impact of doses from intakes of radionuclides upon dose-responses derived using doses from external sources of radiation.