Health physics最新文献

End-of-life (EOL) management of high-activity radioactive sources is made uniquely challenging by the inherent risks associated with storage and transportation of these sources, the complex logistics involved, and the strict requirements for regulatory compliance. Traditional methods lack comprehensive tools for accurate site assessments and precision planning for the transportation of radioactive sources. They also frequently fail to provide the adaptability required to consider diverse operational environments, resulting in inefficiencies and potential safety concerns. This paper introduces a novel software solution developed to address these issues by integrating advanced technologies such as light detection and ranging (LiDAR)-based 3D environment modeling, smart dynamic route planning, and customizable measurement functionalities. This software enables detailed terrain visualizations, facilitating thorough environmental assessments and enabling users to virtually navigate, analyze, and plan site-specific operations. Among the key features are a user-centric interface for virtual navigation, precise site measurement tools for site evaluations, interactive visualizations that highlight potential operational hazards, dynamic route planning capabilities, and real-time collision detection to promote safe workflows. By demonstrating the effectiveness of this tool through real-world application, the present work underscores the tool's potential to revolutionize radioactive source EOL management by improving operational efficiencies, minimizing risk, and advancing the state of practice to achieve suitable and secure radioactive material handling.

This study establishes a robust and clinically applicable calibration protocol for optically stimulated luminescence dosimeters (OSLDs) in diagnostic radiology, with the aim of improving the accuracy of patient dose assessment. A total of 144 OSLDs were systematically irradiated under controlled conditions to assess their dosimetric response across a wide range of tube voltages (40-150 kVp) and square field sizes (10 × 10 cm² to 30 × 30 cm²). The dosimeters exhibited a sensitivity variation of ±6.6%, with an average background dose of 0.0185 mGy. The experimental data revealed a high dependence of OSLD response on photon energy, with dose values increasing by a factor of 11.5, from 0.1393 mGy at 40 kVp to 1.6072 mGy at 150 kVp for a constant field size of 10 × 10 cm². A pronounced non-linear dose escalation was observed in the mid-kVp range (70-100 kVp), where dose measurements increased by 72-90% as field size expanded. Energy and geometry-specific correction factors were derived, showing significant variation with field size, reaching maximum values of 9.81 for the 30 × 30 cm² field at 150 kVp and 7.43 for the 10 × 10 cm² field under the same conditions. Additionally, notable discrepancies were observed between experimentally derived effective beam energies and reference values reported by the International Atomic Energy Agency (IAEA), highlighting the need for localized calibration standards. These findings contribute to the standardization of OSLD calibration protocols in diagnostic radiology and support their implementation for accurate patient dose monitoring in clinical settings.

The anticipated increase in nuclear decommissioning in the coming decades requires innovative approaches to maintain worker exposure as low as reasonably achievable. Occupational dose, an important component of cost-benefit analysis and work planning in decommissioning, can be estimated using radiation transport codes. Monte Carlo N-Particle (MCNP) is a robust, well-established code that has been used to model a breadth of geometries and source terms. Attila4MC offers a graphical user interface for users to build and run MCNP simulations and create an unstructured mesh of computer-aided design (CAD) models with tunable meshing parameters, including element edge length bounds and curvature refinement features. To understand how these parameters might be optimized for a large-scale model for dose estimation, a building containing gloveboxes, a hot cell, ventilation, robotic characterization tools, and operators was modeled in a CAD program. Source terms from available literature were applied to the equipment, and the operator dose was tracked for several exposure geometries. Mesh parameters, including maximum edge length (MEL) bounds, curvature refinement part selection, d/h ratio, and minimum edge length, were varied, and the resulting dose estimates were compared. The upper MEL bound had little effect on the estimated dose rate, but the varying the lower bound resulted in a 40% change in dose rate compared to the default case. Curvature refinement increased the MCNP figure of merit very slightly, about 2.6% when applied globally, but increased by over 31% when applied to only selected parts within the model. Both minimum edge length and d/h ratio showed a maximum change in dose rate of 10% compared to the default case for the values investigated in this study. Finally, the dose rate results suggest that the use of robotic or remote characterization methods may reduce occupational dose to workers by several orders of magnitude for the modeled scenario.

The Moroccan radiopharmaceutical industry is currently under development. The country has two operational cyclotrons capable of producing fluorine-18-labeled radiopharmaceuticals (RPs), primarily for PET imaging, while all other therapeutic and SPECT-dedicated RPs are imported. Importation processes are administratively complex and subject to fluctuations in global supply chains. The RP industry also faces additional challenges, including a stringent regulatory framework, limited accessibility, reimbursement barriers, and a scarcity of trained professionals in radiopharmacy and nuclear medicine more broadly. Furthermore, limited education and awareness among referring clinicians hinder the integration of some nuclear medicine procedures into routine clinical practice. Despite these challenges, Morocco has significant potential for localized RP production. Strategic investment and partnerships with key international agencies could enhance radiopharmacy infrastructure, streamline regulatory pathways for local manufacturing, and foster the development of new training programs for professionals in Morocco and other African countries.

In radiation safety programs, particularly in large healthcare systems, personal dosimetry is often issued conservatively, leading to unnecessary monitoring of individuals with minimal exposure risk. This study describes a structured approach implemented at Mayo Clinic to evaluate the necessity and exchange frequency of dosimeters using two years of retrospective radiation dose data. Personnel were grouped based on job type and workplace conditions, then dosimetry data was analyzed at the 50th percentile, 95th percentile, and maximum levels against conservative thresholds. Regulatory requirements and managerial input were incorporated throughout the decision-making process. From 2020 to 2024, this method resulted in the reduction of dosimeter frequency for 82 individuals and complete removal for 1,067: reducing dosimeter issuance by 4,912 each year. The approach enabled a more efficient use of resources, allowing radiation safety efforts to be directed toward higher-risk groups and activities without compromising compliance or worker protection. This model provides a conservative, scalable framework for optimizing dosimetry programs in healthcare and potentially other radiation-using industries.

According to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) publications, contributions of terrestrial gamma doses are mainly from the presence of 40K, and of 238U and 232Th together with their progeny in various rocks and soils. A survey of soil distributions of radionuclides 40K, 238U, and 232Th was performed at the Nevada National Security Site (NNSS) using in situ gamma-ray spectrometry with a high-purity germanium (HPGe) detector. The average activity concentrations of 40K, 238U, and 232Th in natural soils at the NNSS are 867 Bq kg-1 (range from 150 ± 8 to 1297 ± 56 Bq kg-1), 50 Bq kg-1 (range from 29 ± 3 to 74 ± 8 Bq kg-1), and 56 Bq kg-1 (range from 11 ± 2 to 96 ± 10 Bq kg-1), respectively. The concentration at each location is significantly associated with its geological lithology. The terrestrial gamma dose rates around the NNSS were estimated from 26 to 144 nSv h-1 with mean value of 93 nSv h-1. Our results provide useful information about the natural background radiation and radiological effects of naturally occurring radionuclides at the NNSS.

Substitute materials that accurately reproduce the radiological properties of human tissues are required for direct in vivo measurement of internally deposited radioactive materials to estimate associated health risk, especially for the respiratory tract. The Livermore torso phantom, the de facto standard for calibrating detector systems that measure radioactive materials deposited in the lungs, liver, and thoracic lymph nodes, was designed with tissue substitute materials that match the density and attenuation coefficient exhibited by natural human tissue when exposed to single low-energy x rays associated with the decay of plutonium. In this study, we evaluated the radiometric tissue equivalence of new tissue substitutes for muscle, rib, sternum, lung, and cartilage that are suitable for a continuous low photon energy spectrum from approximately 30 to 120 keV. The formulation for each of the tissue substitutes was developed using a novel method that determines the optimized quantity of base material and additives to produce a material that best matches the density and photon transmission exhibited by the natural human tissue present in the thoracic cavity. Measurements of the mass attenuation coefficient (i.e., ) from approximately 30 keV up to 120 keV for each substitute tissue were within 8% or better to expected values calculated using the photon cross section database XCOM from the National Institute for Standards and Technology.

Due to the widespread use of ionizing radiation in diagnosis and therapy and its associated risks, this study seeks to evaluate the radiation knowledge of pre-interns and residents and find key factors in this regard. This research was conducted at an educational hospital involving 56 pre-interns and 42 radiotherapy and radiology residents. The questionnaire contained fifteen questions about radiobiology, radiation knowledge basics, and ionizing radiation protection principles. The findings revealed that pre-interns had a mean score of 60.48 ± 11.69, whereas radiology and radiotherapy residents had mean scores of 55.75 ± 9.11 and 82.00 ± 13.06, respectively. The knowledge level of radiotherapy residents was significantly higher than other groups in every section (P-value<0.0001), with no significant difference found based on gender. The mean level of knowledge varies by academic degree. Pre-interns scored significantly lower than residents (P-value<0.05). The higher level of radiation knowledge within the cohort of radiotherapy residents underscores the pivotal role of continuous learning through objective experience. Given their professional focus on the use of ionizing radiation, this group is objectively in ongoing training.

Radiation exposure in the catheterization laboratory poses a significant occupational hazard for primary operators. This single-center, open-label, randomized controlled trial conducted at Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, evaluated scattered radiation exposure to the primary operator during procedures via radial, femoral, and pectoral vascular access sites and the effectiveness of radiation protection drapes in reducing this exposure. A total of 216 patients (72 in each vascular access group) were randomized using coin flipping to receive either standard radiation protection or additional shielding with a radiation protection drape. The primary operator's scattered radiation dose was assessed in comparison to the radiation emitted during the procedure, with normalization to procedural radiation parameters including air kerma (AK), dose area product (DAP), and cine-adjusted screen time (CAST). Pectoral access was associated with the highest operator exposure (96.75 µSv) compared to femoral (45.72 µSv) and radial (49.06 µSv) access, despite lower AK values. Radiation protection drapes significantly reduced operator exposure across all access sites, with radial access showing reductions of 51% (DAP), 48% (AK), and 53% (CAST); femoral access showing reductions of 82% (DAP), 74% (AK), and 63% (CAST); and pectoral access showing reductions of 62% (DAP), 49% (AK), and 52% (CAST), all statistically significant (P < 0.05). No adverse events were reported. The findings provide strong support for the routine use of radiation protection drapes to minimize primary operator radiation exposure during catheterization procedures, especially when using the pectoral access site.

The principle of justification is intended to ensure the net benefit of a proposed activity that would alter radiation exposure. While the concept is simple and easy to understand, its application, including the basis for judgments and the process for reaching a decision, is not straightforward. It has been demonstrated in the last decades that the decision-making process in radiological protection and safety requires not only scientific and technical rationality but also consideration of stakeholder views to appropriately reflect societal and ethical values. In view of these emerging challenges, the International Commission on Radiological Protection created Task Group 124 for the purpose of revisiting and modernizing the principle of justification. The Task Group collected various views and opinions of radiation protection experts through an online workshop and an international conference. They were examined to identify areas that need further clarification and to extract ideas that were not given sufficient consideration in the past. The Task Group is working to compile a report that identifies essential elements and key perspectives in the decision-making process for justification. It aims to clarify what "do more good than harm" means in society today and on what basis the judgment should be made.