Health physics最新文献

Abstract: The primary purpose of this study was to report the mean glandular doses and to determine the national diagnostic reference levels for digital mammography based on data between 2016 and 2018 in China. The data from 19,076 mammograms (4,769 examinations) by random sampling from 118 digital mammography systems were compiled. Exposure factors included age, compressed breast thickness, kVp, mAs, target/filter combination, entrance surface air kerma, and mean glandular doses, which were retrospectively surveyed and recorded from the monitor. The national diagnostic reference levels (75th percentiles) in mean glandular dose were calculated across median value obtained for all included data and stratified to specific compressed breast thickness ranges. The patients' ages ranged from 22 to 88 y, with a median age of 45. The applied voltage and output medians were 28 kVp and 75.1 mAs for all exposure, respectively. The median CBTs were 45 mm and 48 mm for craniocaudal views and mediolateral oblique views, and the corresponding median mean glandular doses were 1.32 mGy and 1.40 mGy, respectively. The national diagnostic reference level at compressed breast thickness of 40-50 mm was 1.67 mGy for CC views and 1.71 mGy for MLO views. The median mean glandular doses varied significantly and increased with compressed breast thickness, demonstrating the necessity of establishing DRL according to breast thickness and optimizing the clinic's digital mammography practice in China.

Abstract: Hazardous Materials (HAZMAT) Technicians' notions of mental model, or cognitive representations of their understanding and beliefs regarding Radiological Dispersal Devices (RDDs) incidents, have not been previously explored. A prior study developed an Expected Mental Model State (EMMS) framework specific to RDD incident response for HAZMAT technicians. The work herein presents the development of a derivative of this framework, the EMMS Diagnostic Matrix, to evaluate the actual Mental Model State (MMS) of HAZMAT technicians in the context of RDD incidents. The EMMS Diagnostic Matrix was administered via a survey and simulation activity in four U.S. states representing the Northeast, West, South, and Midwest regions. Data were collected and coded using grounded theory methodology. Reflexive thematic analysis was employed to identify themes across related areas where the notions of mental model for the HAZMAT technician responders' actual MMS differed from the EMMS. The analysis of the collected data revealed four significant themes representing incomplete notions of the mental model spanning various EMMS conceptual domains: Overestimation of Radiation Dose and Health Effects, indicating misunderstandings about the health impacts of radiation exposure, Acute Radiation Syndrome (ARS), particularly in the lower range of radiation doses; Overreliance on Responder Protection [personal protective equipment (PPE)/self-contained breathing apparatus (SCBA)], highlighting gaps in understanding radiation principles and radioactive material dispersal properties from a radiological dispersal device; Misunderstanding Radiation Detection and Units, signifying confusion about radiation units and differentiation between dose rate and accumulated dose; and Incomplete Understanding of Radiation Characteristics and Dispersal Properties, outlining a limited grasp of inhalation risks from radiation and the dispersal traits of a radiological dispersal device. The interconnectedness of these technical misunderstandings can guide the development of a strategic plan to evaluate and modify existing training, aiming at these specific themes to improve the efficiency of HAZMAT technicians in emergency situations and to identify areas for further research.

Abstract: Naturally occurring uranium complicates monitoring for occupational exposures. There are several retroactive methods that can be used to monitor for occupational exposures, with benefits and drawbacks to each. Analysis of uranium in urine by mass spectrometry and alpha spectrometry is compared, and methods of determining an occupational exposure are presented. The minimum detectable concentrations from each analysis and a method for intake determination based on the analytical results are compared for various solubility types and mixtures. Mass spectrometry with radiochemical separation was found to be the most sensitive analysis for detecting occupational exposures to anthropogenic mixtures based on minimum detectable doses calculated from the proposed method for intake determination.

Abstract: US Department of Energy national laboratories can play an integral role in not only the advancement of science but also in the treatment of various medical conditions through research and development activities conducted at radioisotope production facilities. A project has been underway at Oak Ridge National Laboratory since 2016 whose mission is to produce and supply the radioisotope 227Ac, which is used in a radiopharmaceutical developed to treat certain types of prostate cancer and bone metastases. Production activities result in the environmental release of airborne radioactive emissions, which are governed by Clean Air Act regulations described in 40 CFR Part 61, Subpart H. Stack 3039, the source that emits radioactive effluents from 227Ac production, is subject to additional requirements outlined in American National Standards Institute (ANSI) N13.1-1969 due to its grandfathered status. Radioactive emissions are limited to levels below those that would cause annual compliance dose standards for members of the public to be exceeded and stack 3039 to lose its grandfathered status. To allow for maximum production of 227Ac without exceeding relevant dose limits, monthly tracking of project emissions and resulting CAP88-PC modeled effective doses to a maximally exposed individual have been implemented. Four years of tracking data were compiled and analyzed to identify additional methods that could be used to estimate project doses more frequently, potentially further optimizing 227Ac production while maintaining compliance with applicable regulations.

Abstract: The present work models plutonium (Pu) biokinetics in a female former nuclear worker. Her bioassay measurements are available at the US Transuranium and Uranium Registries. The worker was internally exposed to a plutonium-americium mixture via acute inhalation at a nuclear weapons facility. She was medically treated with injections of 1 g Ca-DTPA on days 0, 5, and 14 after the intake. Between days 0 and 20, fecal and urine samples were collected and analyzed for 239Pu and 241Am. Subsequently, she was followed up for bioassay monitoring over 14 y, with additional post-treatment urine samples collected and analyzed for 239Pu. The uniqueness of this dataset is due to the availability of: (1) both early and long-term bioassay data from a female with plutonium intake; (2) data on chelation therapy for a female; and (3) fecal measurement results. Chelation therapy with Ca- and/or Zn-salts of DTPA is known to aid in reducing the internal radiation dose by enhancing the excretion of plutonium and americium from the body. Such enhancement affects plutonium biokinetics in the human body, posing a challenge to the internal dose assessment. The current radiation dose assessment practice is to exclude the data affected by Ca-DTPA from the analysis. The present analysis is the first to explicitly model the chelation-affected bioassay data in a female by using a newly developed chelation model. Thus, the bioassay data collected during and after the Ca-DTPA administrations were used for biokinetic modeling and dose assessment. The Markov Chain Monte Carlo method was used to investigate model parameter uncertainty, based on the bioassay data and assumed prior probability distributions. A χ2/nData (number of data points) ≈ 1 was observed in this study, which indicates self-consistency of the data with the model. Results of this study show that the worker's 239Pu intake was 12 Bq, with a committed effective dose to the whole-body of 1.2 mSv and a committed equivalent dose to the bone surfaces, liver, and lungs of 37.8, 9.1, and 0.8 mSv, respectively. This study also discusses the worker's dose reduction due to chelation treatment.

Abstract: Nuclear safety and security are essential elements of radiation protection. Integration of nuclear safety and security provides a means to identify conflict and synergy points. Research has not been performed to enable integrated practices at the facility level. A tool was developed through research to help staff and regulators assess the level of integration practiced within a research reactor. This tool aims to improve the identification of synergistic and conflict points. Eight criteria of nuclear safety and security integration were used to create the integration assessment tool: access control, transportation, emergency response, proper disposal of materials, testing and maintenance, defense in depth, training and education, and culture. The tool's final score can range from 0.0375 to 1, with a score of 1 indicating complete integration. The tool was used by research reactor staff to assess practiced integrative techniques. The testing and maintenance criterion scored the highest level of integration (0.84). Training and education and culture scored the lowest levels of integration (0.50). The areas with the highest scores identified points of actively practiced integration. In contrast, those areas with lower scores indicated a lack of integrative practices. The total integration score was 0.69. This tool determined that the facility practiced an adequate level of integration. By analyzing integration levels with this tool, a measurable standard of integrative practices can be employed to achieve improved radiation protection.

Abstract: The purpose of this article is to describe the activities developed within the framework "Regional Workshop on Optimization of Protection in Pediatric Interventional Radiology in Latin American and Caribbean countries," developed between October 16th and 19th of the year 2023 in the city of San José, Costa Rica. The workshop was carried out as part of a joint work between the Pan American Health Organization (PAHO) and the World Health Organization (WHO), in cooperation with the International Atomic Energy Agency (IAEA). The main objective of the regional workshop was to gather the experiences and future work planning among participants in the Optimization of Protection in Pediatric Interventional Radiology in Latin America and the Caribbean (OPRIPALC) program. It involved professionals from 14 centers across 11 countries in the region, along with 4 experts from PAHO/WHO/IAEA. The work modalities during the workshop consisted of keynote presentations, individual presentations, group work, and general discussions. An online survey was carried out after the workshop, with the objective of knowing the opinion of the event participants and determining the impact and projection of the OPRIPALC program. During the workshop the centers had to present their experiences: the use of the DOLQA dose management system was presented and work was done on the consensus document on good practices. The activities, topics and organization of the workshop were valued positively by the participants. There is unanimity among the centers that the OPRIPALC program has had a positive impact and they wish to continue actively participating in the next biennium.

Abstract: In this particular investigation, 30 surface soil samples taken from various locations across the Middle Omara governorate in southeastern Iraq were analyzed using ICP-MS (inductively coupled plasma mass spectrometry), and several of these, as far as the researchers know, had never been analyzed previously. The results are presented and compared with those from a different study. The studied soil samples had <100 ppm of uranium, which shows they are composed of overloads and garbage rather than mineable stocks. This article describes and assesses the uranium content in the Middle Omara Governorates. Additionally, all 30 exposed earth samples had uranium below the detection threshold. The results show that the samples of surface soils under investigation have uranium concentrations below the permissible maximum (11.7 ppm) established by UNSCEAR in 1993.

Abstract: The As Low As Reasonably Achievable (ALARA) principle includes taking into account economic and societal factors. To consider these factors, decision-aiding techniques such as cost-benefit analysis were introduced by the International Commission on Radiological Protection (ICRP) 50 y ago. Over the years, developments in health economics have led to new ways of deriving the concept of a value of a statistical life (VSL), which now is influencing the monetary value assigned to a unit of collective dose for radiological protection purposes (the α value) used in cost-benefit analyses. The aim of the present study was to estimate an α value useful for occupational radiological protection within the healthcare system of Sweden. A survey based on the stated preference approach was developed and sent to staff who are exposed to ionizing radiation at their work in Region Västra Götaland (Sweden). The survey essentially contained two scenarios: the respondents' willingness to pay for measures against radon exposure at home and their willingness to accept compensation for x-ray exposure at work. Answers from 718 respondents were collected. In the sensitivity analysis of the survey, the overall median VSL based on the two scenarios was calculated to be $50 million (IQR $10 to 363 million). The corresponding α value was established to $1,600 person-mSv -1 ($2,100 person-mSv -1 if excess burden of taxes is excluded). The recommended α value is in the high end compared to other studies but within the interval of values being used by nuclear utilities today. The α value should be seen in the light of ICRP's recommendation about stakeholder involvement as an important part of the optimization process.

Abstract: At the University of Alabama at Birmingham (UAB), many diagnostic and therapeutic procedures involving radioactive materials or radiation-producing machines are performed daily. A growing number of minor but preventable incidents related to radiation safety have brought up concerns related to the effectiveness of the training program. A comprehensive literature review was performed to summarize post-COVID insights into andragogic online training practices, statistical analyses, and overall retention competencies in radiation safety. Andragogic research shows that the best method of training adult learners is controlled simulation that tests critical thinking and problem-solving capabilities, drawing upon previous knowledge or experiences. A new training curriculum based on these andragogic principles was designed and administered to a subgroup of UAB radiation workers. Scores from pre-testing and post-testing were collected and analyzed. An ANCOVA was used to account for differences in the pre-test scores between the control and experimental groups, which was found to be statistically significant (p = 0.018), suggesting that small changes in a radiation safety training program can have significant impacts in retention of key information.