Health physics最新文献

Abstract: This research evaluates the effectiveness of a large specialized cardiac catheterization laboratory shielding device (SCCLSD) placed perpendicular to the patient compared to traditional shielding methods in reducing occupational exposure to scattered x rays, contributing to the ongoing enhancement of radiation safety in the cardiac catheterization laboratory (CCL) setting. An experimental setup involving an anthropomorphic phantom on the catheterization table simulated radiation scatter from a patient. Measurements were taken systematically at various grid points and heights in the CCL using a Fluke 451P ion chamber while mimicking a real interventional scenario. In-air peak exposure rates were analyzed at head, chest, and waist heights in the anteroposterior (AP) position. Results demonstrated that the SCCLSD provided a superior radiation shadow and effective whole-body radiation exposure reduction compared to conventional shielding devices. Considering that conventional shielding requires staff to wear lead aprons, an effective dose equivalent correction factor was applied for exposure measurements without the SCCLSD. Even after the correction factor, the SCCLSD continued outperforming lead aprons and offered whole-body protection, including the head and arms, which is typically neglected with conventional shielding. The SCCLSD also reduces exposure to the eyes, aligning with lower occupational exposure recommendations from ICRP and NCRP. However, proper CCL staff positioning is important in maximizing the effectiveness of the SCCLSD. Future research avenues may explore exposure rates at different C-arm angles to more completely assess the SCCLSD's impact on occupational exposure.

Abstract: In medical physics, rigorous quality assurance and quality control protocols are vital for precise dose delivery applications. In many health physics applications, the allowable uncertainty for various processes is often greater than that of medical physics due to looser safety ties. This results in less demand for quality control and uncertainty analyses, since these may not be needed. However, certain applications can benefit from a comprehensive quality control program, as it may yield important insights, such as air kerma monitoring in dosimetry calibrations for environmental and low-dose applications. By implementing a thorough quality control program tailored to specific contexts and needs, uncertainties associated with dose measurements can be quantified with greater accuracy and reliability. This proactive approach not only ensures the integrity of data collected but also enhances understanding of the measured doses. For these reasons, a comprehensive quality control initiative was implemented following documented failures in a 137 Cs dosimetry calibration irradiator. This involved systematic charge collection using NIST-traceable ion chambers to observe long-term changes. A Phase I quality control protocol was previously implemented, which employed Shewhart control charts and Nelson's rules to analyze various datasets subgrouped under different conditions. This study addresses the development of a Phase II protocol, which focuses more on uncertainty quantification of systematic errors and irradiator changes, and air kerma precision for dosimetry calibrations. A designed experiment was performed to identify how much systematic errors influence the air kerma. Emphasis was placed on stricter quality assurance protocols, continuous data collection, and additional control charts to monitor short-term changes, such as exponentially weighted moving average control charts. A pre-irradiation control process was implemented to verify that the total air kerma met the measurement quality objective and to show how various uncertainties were applied before calibration. This study indicates how uncertainty is applied given observed air kerma measurements from the irradiator. Ongoing efforts aim to streamline the quality control procedure, ensure consistent data collection, and assess its impact on dosimetry applications.

Abstract: Affordable, accurate, and robust temporal measurement devices are desirable for screening and assessment of radon levels in private homes and workplaces. This research expands upon prior research, using the RadonFTlab RadonEye device through a comparison of multiple samples of this instrument with a laboratory-grade instrument, the Saphymo AlphaGUARD, over a more extensive period than reported previously. Data were collected over 291 d in a poorly ventilated basement space in an occupied building. Environmental conditions varied naturally, changing both the radon source term and radon entry into the space approximating typically deployed conditions. The R-squared linear regression correlation coefficient and relative sensitivities of each RadonEye with the AlphaGUARD were computed. Overall temporal and diurnal variations were also studied. The sensitivities of all RadonEyes and the AlphaGUARD agreed to within 22% throughout the entire deployment period.

Abstract: A comprehensive radiological study was conducted in the surrounding public zones of the Nevada National Security Site to identify traces of resuspended radioactivity and heavy elemental contamination that might have resulted from various activities. The study used passive and active nuclear methods, specifically gamma spectrometry and instrumental neutron activation analysis, respectively. Passive gamma spectra analysis of air filter papers from various Community Environmental Monitoring Program stations conclusively verified the presence of radionuclides exclusively originating from the natural decay series of 238 U and 232 Th. Furthermore, gamma spectrometry and instrumental neutron activation analysis of plant samples from surrounding areas of the Nevada National Security Site revealed the absence of any unusual elemental contamination in the environment. These results demonstrated that there was no measurable radiological impact on the public zones surrounding the site resulting from the spread of radioactive materials or toxic heavy metals associated with previous or ongoing activities at Nevada National Security Site. Therefore, the safety of public zones concerning retained radioactivity and harmful elemental contamination arising from Nevada National Security Site operations is negligible. The significance of this study is further pronounced in the current geopolitical context, as it establishes the baseline elemental composition for various desert plants for future reference.

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: 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.

Abstract: Radiation protection contains the key elements of nuclear safety and security. Despite the overlap between nuclear safety and security, their objectives differ fundamentally, focusing on unintentional accidents and intentional malicious events, respectively. As such, the Potential Facility Risk Index (PFRI), originally created for security purposes, has evolved into an approach that combines conventional probabilistic risk assessment (PRA), which is a widely employed method to evaluate the safety risks of nuclear facilities. This research has developed a risk assessment model within the PFRI framework to calculate the probability of nuclear terrorism. Three essential components of the model are integrated: an analysis of historical nuclear terrorism data to determine an initial threat frequency; the target-specific factor using analytical hierarchy process (AHP) target attractiveness analysis; and the adversary motivation factor based on site-specific social influences from the Profiles of Individual Radicalization in the United States (PIRUS) dataset. Applied to a hypothetical nuclear facility, the model produces a nuclear terrorism probability of 8.97 × 10 -3 y - 1 . The systematic methodology proposed in the study enables the derivation of nuclear terrorism probability with results in the same risk unit as safety risk assessment. This method allows decision makers to seamlessly incorporate nuclear safety and security risk assessments, offering a comprehensive perspective. Consequently, it enriches comprehension of nuclear facility risks and establishes the groundwork for future advancements.

Abstract: In the last 30 y, observational as well as experimental studies have addressed possible health effects of exposure to radiofrequency electromagnetic fields (EMF) and investigated potential interaction mechanisms. The main goal of ICNIRP is to protect people and the environment from detrimental exposure to all forms of non-ionizing radiation (NIR), providing advice and guidance by developing and disseminating exposure guidelines based on the available scientific research on specific parts of the electromagnetic spectrum. During the development of International Commission on Non-Ionizing Radiation Protection's (ICNIRP's) 2020 radiofrequency EMF guidelines some gaps in the available data were identified. To encourage further research into knowledge gaps in research that would, if addressed, assist ICNIRP in further developing guidelines and setting revised recommendations on limiting exposure, data gaps that were identified during the development of the 2020 radiofrequency EMF guidelines, in conjunction with subsequent consideration of the literature, are described in this Statement. Note that this process and resultant recommendations were not intended to duplicate more traditional research agendas, whose focus is on extending knowledge in this area more generally but was tightly focused on identifying the highest data gap priorities for guidelines development more specifically. The result of this distinction is that the present data gap recommendations do not include some gaps in the literature that in principle could be relevant to radiofrequency EMF health, but which were excluded because either the link between exposure and endpoint, or the link between endpoint and health, was not supported sufficiently by the literature. The evaluation of these research areas identified the following data gaps: (1) Issues concerning relations between radiofrequency EMF exposure and heat-induced pain; (2) Clarification of the relation between whole-body exposure and core temperature rise from 100 kHz to 300 GHz, as a function of exposure duration and combined EMF exposures; (3) Adverse effect thresholds and thermal dosimetry for a range of ocular structures; (4) Pain thresholds for contact currents under a range of exposure scenarios, including associated dosimetry; and (5) A range of additional dosimetry studies to both support future research, and also to improve the application of radiofrequency EMF exposure restrictions in future guidelines.Health Phys. 128(0):000-000; 2025.

Abstract: Three topics related to ANSI/HPS Standard N13.56, Sampling and Monitoring Releases of Airborne Radioactivity in the Workplace, are discussed. First, due to the omission of consideration of the activity's half-life in the standard's continuous particulate air monitor (CPAM) quantitative method, it is possible for concentration estimates produced by that calculation to be underestimated. Second, the concentration estimate found in air grab sampling, as discussed in the standard, is not, as claimed, an average unless the activity is "long-lived" (negligible decay during sampling). It is nonetheless possible for this calculation to produce a concentration estimate that is not significantly different from the average, depending on both the half-life of the activity and the sampling time. Third, the issue of when to change the filter for the CPAM method is addressed.

Abstract: The roles and responsibilities of radiation safety officers (RSO), medical health physicists (MHP) and diagnostic medical physicists (DMP) have evolved significantly over the past 20 years. With the availability of enterprise software systems and aggregated data platforms for various radiologic healthcare systems, the roles of these professions are expanding beyond their original scopes in managing the Radioactive Materials License (RSO, MHP) and Machine Specific Physics Testing (DMP). Workers in medical radiation safety are transitioning from siloed workers working within their specific disciplines as new emerging technology and clinical care require these roles to evolve. This paper aims to demonstrate the value in embracing the change in these roles to better serve the patients and occupational workers RSOs, MHPs, and DMPs serve. As medical physics enterprise solutions evolve, so will the relationships between these valuable stakeholders.