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P - Poster Session

Prince George's A&B Exhibit Hall   Monday 10:00 AM until Wednesday 10:00 AM

 
P.1  Poster Session   High radiation exposure works in Korean nuclear power plants TY Kong*, Chosun University ; SJ Kim, Chosun University; JH Son, Chosun University; CJ Song, Chosun University

Abstract: The 2007 Recommendation of the International Committee on Radiological Protection (ICRP) proposed using a dose constraint as an optimization tool to lessen the potential inequity of radiation exposure between individuals. Currently, the Korean regulatory body conducts research to implement dose constraints in all nuclear and radiation industries. According to the annual reports of occupation exposure in Korean nuclear power plants (NPPs), the annual average individual dose was 0.5 - 1.4 mSv during the years 2009-2018, which means that the average dose in Korean NPPs accounted for only 1.0 - 2.8% of the annual occupational dose limit. Although most radiation workers in Korean NPPs received very low levels of occupational exposure, some received relatively higher annual radiation doses than others. This study investigated the high radiation exposure works in Korean NPPs, using the occupational exposure records in Korean NPPs, which contribute to the potential inequity of radiation exposure. The study result showed that most of the occupational radiation exposure occurred during the maintenance period, approximately 90%, which indicated that radiation exposure under routine operation accounted for only 10%. The highest radiation exposure work in Korean NPPs was the steam generator maintenance, including the opening and closing of the manway, installment and removal of the nozzle dam, and eddy current tests. Acknowledgments This work was supported by the National Research Foundation of Korea grant funded by the Korean government (MEST) (No. RS-2022-00144506).

P.2  Poster Session   Radiation Safety Training in Switzerland - an Overview MF Keller*, Paul Scherrer Institut

Abstract: Radiation safety training requirements are regulated in a fair amount of detail in Switzerland. Besides the Radiological Protection Act (814.50) and the Radiological Protection Ordinance (814.501), both of which have an official English translation, the Strahlenschutz-Ausbildungsverordnung (radiation protection education regulation, 814.501.261) details the competences and learning objectives for five employment spheres, ranging from medicine to nuclear power plants, and over 60 individual professions. Further training details are provided in numerous guidance documents from the Federal Office of Public Health (BAG), the Swiss Federal Nuclear Safety Inspectorate (ENSI), and others. An overview of the requirements, and how some of the training courses are implemented at the PSI Education Center, is given.

P.3  Poster Session   Occupational ionizing radiation exposure monitoring in several medical departments NA Alomairy*, Diagnostic Radiography Technology Department, Faculty of Applied Medical Sciences, Jazan University, Jazan 45142, Saudi Arabia ; na alomairy

Abstract: Occupational ionizing radiation doses for medical radiation workers (MRWs) from different medical departments in a major specialized hospital in Saudi Arabia were measured and analyzed to establish a baseline for the annual mean effective dose (AMED) for MRWs. A statistical analysis of dose records was conducted on effective doses for 355 MRWs in the following medical departments. The overall AMED for all MRWs reported in this study was 1.60 mSv. The AMEDs in each medical department were 1.17 mSv in diagnostic radiology, 1.61 mSv in interventional radiology, 2.72 mSv in nuclear medicine, 1.59 mSv in radiation therapy, 1.32 mSv in operation room, 1.06 mSv in dentistry, and 1.54 mSv in others. A one-way ANOVA test indicated statistically significant differences between the departments’ workers (P = 0.001). The study reveals that the workers in the nuclear medicine department received the highest AMED among the other workers. The results reveal that no single occupational dose has exceeded the annual dose limit of 20 mSv. However, to avoid unwanted radiation exposures, it is still required to control Q1 the workplace and manage MRWs, particularly for workers in NM, who were found to get more dose than MRWs in other medical departments

P.4  Poster Session   Development of radiological triage criteria for internal contamination applied in radiological disaster KH KIM*, Korea Institute of Radiological & Medical Sciences ; JR YOO, Korea Institute of Radiological & Medical Sciences

Abstract: In a disaster, the medical supply becomes insufficient compared to increasing medical demand. Therefore, to perform rapid and effective medical response, the patient's triage criteria are prepared and limited medical resources are appropriately distributed. Thus it is required to establish the radiological triage criteria prior to radiological disaster. In this study, triage criteria for internal contamination that can be applied in a radiological disaster were developed. Two steps were performed to develop radiological triage criteria. First, the medical responses were classified by level of radiation dose. In the case of an effective dose being under 20 mSv, treatment should not be considered; 20 mSv ~ 100 mSv, treatment is subject to medical judgment; and over 100 mSv, treatment has to be considered respectively. Second, each effective dose level was expressed as radiation mesurement results based on in-vivo, in-vitro bioassay. Results were taken into account radionuclides, intake date, intake pathways, particle properties, and measurement methods. In the case of in-vivo bioassay, effective dose was converted to radioactivity retained in the human body. In the case of in-vitro bioassay, effective dose was converted to radioactivity excreted from the human body. In the case of I-131 inhalation, measured 1 day after intake, it was evaluated that the committed effective dose would be 20 mSv that the thyroid retains 2.27×105 Bq and 100 mSv that the thyroid retains 1.14×106 Bq. In the case of measured 10 day after intake, it was evaluated that the committed effective dose would be 20 mSv that the thyroid retains 1.05×105 Bq and 100 mSv that the thyroid retains 5.16×105 Bq. It is applicable to perform rapid and effective triage in a radiological disaster. This study was supported by a grant from the Korea Institute of Radiological and Medical Sciences (KIRAMS), funded by the Nuclear Safety and Security Commission (NSSC), Republic of Korea.(No.2104038)

P.5  Poster Session   Worker Exposure Scenarios during Incident-Free Overland Transportation of Radioactive Wastes MW Kwak*, Kyung Hee University ; HJ Kim, Kyung Hee University; GE Oh, Kyung Hee University; KP Kim, Kyung Hee University

Abstract: The generation of radioactive wastes is increasing in Korea. For disposal of the radioactive wastes, the demand of transportation is expected to increase. Prior to transportation, it is necessary to evaluate the radiation risk of transportation. As a preliminary study for the assessment of radioactive waste transportation risk, we analyzed scenarios of radiation exposure to the workers. Considering the characteristics of Korean situation, truck/trailers were fixed as means of transportation. Since there is no leakage of radioactive materials during incident-free transportation, only external exposure was considered. The exposure situation included truck drivers and handlers. The truck drivers were fixed at specific points during transportation, such as the driver’s seat or passenger’s seat. When assessing the risk of truck drivers, the dimension of the package, a distance between the packages and truck drivers, speed of the vehicle, the length of the transportation route, and the vehicle shielding were considered. According to the size, the handlers were divided into handlers of small and of medium/large packages. Small package was small enough to readily manipulated by a single person. When assessing the risk of handlers of small packages, we considered the dose rate of packages and the number of packages, etc. The handlers of medium/large packages were divided into remote and close workers. Remote works included crane operation, forklift operation, etc., close works included radiological inspection, the attachment/detachment of rigging equipment, etc. For the remote works, the packages were assumed a point source, while for the close works, they were assumed to be a line source. When assessing the risk of handlers of medium/large packages, the dimension of the package, we considered a distance between the packages and handlers, working time, the number of packages etc. This study results will be used as a basis for the waste transportation risk assessment. *This work was supported through the KoFONS using the financial resource granted by NSSC. (No. 2106041)

P.6  Poster Session   Development of Radiation Source Activity Prediction Algorithm for Worker Dose Assessment in Nuclear Power Plants MS KIM*, Kyung Hee University ; HJ NA, Kyung Hee University; JY KIM, Kyung Hee University; HW LEE, Kyung Hee University; KP KIM, Kyung Hee University

Abstract: Workers in nuclear power plants are exposed to radiation sources in various situations. Therefore, it is necessary to establish an optimized work plan by assessing the worker radiation dose before performing the work. However, source information can be insufficient in some situations, and analyzing the activity of major sources in all working environments is limited in terms of time and cost. Therefore, the technology that can predict the source activity and assess the radiation dose of workers based on the data must be developed. In this study, we developed a radiation source activity prediction algorithm for dose assessment of worker in nuclear power plants. The radiation source activity prediction algorithm inversely calculates the activity of the source by utilizing the position of the source and shielding information based on the measured radiation dose rates in the workplace. However, in actual workplaces, it is not possible to derive an accurate source activity corresponding to the measured data due to various uncertainties such as heterogeneity of material density, dosimeter errors, etc. Therefore, in this study, the Successive Over-Relaxation (SOR) method was used to derive the optimal source activity. Through this method, the source activity of the minimum error corresponding to the measurement data was derived, and the radiation dose of workers can be assessed based on the information. Based on the developed algorithm, we assessed the radiation dose of workers based on the measurement data in a virtual working situation, and compared and verified it through Microshield software. As a result, the source activity and the radiation dose of workers had a error rate of about 1%. The results of this study can be used as a basis for radiation worker dose assessment. * This work was supported through the National Research Foundation of Korea (NRF) using the financial resource granted by the Ministry of Science and ICT (MSIT). (No. RS-2022-00143994).

P.7  Poster Session   Analysis of Airborne Particulate Property Based on Industrial Field Information of the Refractory Industry SY Lee*, Kyung Hee University ; HJ Na, Kyung Hee University; SH Jeon, Kyung Hee University; J Kwon, Korea Institute of Nuclear Safety; KP Kim, Kyung Hee University

Abstract: Zircon is a representative NORM and used as a raw material in various industries due to its thermal and chemical stability. In consideration of the radiological impact of zircon, the IAEA included the zircon and zirconia industry in major NORM industries that need regulatory consideration. In Korea, powdered zircon is used as a raw material for manufacturing refractories. Therefore, as part of the radiological safety management, the internal radiation dose must be assessed by reflecting the particle property of the industrial field. In this study, as a preliminary study of internal radiation dose assessment, we analyzed particle properties based on industrial field information of refractory industry. Particle concentration by size, density, shape, and radioactivity concentration were selected as particle properties to be analyzed. The particle concentration by size was analyzed using cascade impactor at main process points. The density was analyzed using a pycnometer after taking a sample of the handling material. The shape was analyzed using SEM for the dust collected by the cascade impactor. The radioactivity concentration was analyzed using HPGe for Ra-226, Ra-228 contained in the main handling materials. The particle concentration ranged from 0.316~0.986 ?g/L, and the highest concentration was found around the geometric mean diameter of 3.94 ?m. The density was found to be 3.1~5.8 g/cm3. The shape was generally similar to that of a sphere in all main process points. The radioactivity concentration was 0.253~3.869 for Ra-226 and 0.168~0.993 Bq/g for Ra-228. As a result of the analysis, the particle properties of the refractory industry were found to be different depending on work types and origin of raw materials. The results of this study are expected to be used as basic data for the radiological safety assessment of workers in the domestic NORM industry. *This work was supported through the KoFONS using the financial resource granted by NSSC. (No. 2105035)

P.8  Poster Session   Development of method for assessing dose to the public applicable to long-term measures in radiation emergency response BM Lee*, Korea Institute of Radiological and Medical Sciences, Seoul ; JR Yoo, Korea Institute of Radiological and Medical Sciences, Seoul

Abstract: After the Fukushima nuclear power plant accident in Japan, concern about radiation emergency response is growing. The IAEA recommended dividing radiation emergency response into short-term phase, mid-term and long-term phase. However, compared to the short-term and mid-term, the establishment of a response plan for long-term measures was insufficient. it was because various factors such as society, economy, and stakeholders should be considered. And, in Korea, the method for assessing the dose to the public to be applied to radiation emergency response for long-term measures has not been clearly established. Therefore, in this study, a method for assessing the dose to the public that can be used for long-term measures in radiation emergency response was established. Dose assessment includes (1) definition of the source term, (2) selection of exposure scenario and intake route, (3) selection of critical groups and habit data. Source term can be selected based on the results of the environmental impact assessment conducted after the radiation accident. Exposure scenarios and intake routes should be selected in consideration of the resident age and occupation. The critical group should be selected around the point where the person's actual living area. For habit data, the representative person concept presented by ICRP Publication 101 was adopted. In the case of the highest dose contribution, the 95th percentile value was used. And the average value was used for the rest. Through the above considerations, it is possible to perform dose assessment for the public in contaminated area due to radiation accident. This method can be used for dose assessment for residents' health effects and local recovery among long-term measures in radiation emergency response.

P.9  Poster Session   Estimation of Dietary Intake of Strontium-90 in Japan after the Fukushima Daiichi Nuclear Power Plant Accident H Nabeshi*, National Institute of Health Sciences ; A Hachisuka, National Institute of Health Sciences; R Matsuda, National Institute of Health Sciences; R Teshima, National Institute of Health Sciences; H Akiyama, National Institute of Health Sciences; T Tsutsumi, National Institute of Health Sciences

Abstract: Radionuclide contamination in foods has been a public concern in Japan after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. Although the main radionuclide of concern is radioactive cesium (cesium-134 and cesium-137), strontium-90 is also a concern from the FDNPP accident due to its strong radioactive effect and relatively long physical half-life. Therefore, to estimate time and regional trends of daily intake and annual committed effective dose of strontium-90 after the accident, we analyzed market basket samples using a low background 2? gas-flow counter. Market basket samples were prepared based on regional average daily food consumption data from the National Health and Nutrition Examination Survey (male and female, ? 1 year of age) in Japan. Samples were collected from six regions (three areas of Fukushima, Tokyo, Osaka, and Nagasaki), once a year from 2013 to 2018. There was little variation in estimated daily intake and annual committed effective dose of strontium-90 across the time periods and regions. The estimated maximum annual committed effective dose of strontium-90 during the 6-year duration of the study was 0.00076 mSv/year, a value sufficiently lower than the intervention exemption level, 1 mSv/year, in foods in Japan. There was no noticeable difference between the range of estimated daily intake of strontium-90 compared with daily intake measured before the FDNPP accident. These results suggested that there was no obvious increase in dietary intake of strontium-90 after the FDNPP accident, and that effects on commercial foods from strontium-90 due to the FDNPP accident were negligible.

P.10  Poster Session   20 Years of Online Education in Master of Radiation Health Physics at Oregon State University L Ranjbar*, Oregon State University

Abstract: The School of Nuclear Science and Engineering (NSE) at Oregon State University offers a fully online Master of Radiation Health Physics program. This online graduate program was approved to be offered in the fall of 2003 primarily due to a major U.S. Department of Energy grant and today produces the most graduates of any radiation health physics program in the Nation. This paper reviews the advances made in providing high-quality online education and strategies to deliver lab courses to a wide variety of distance learners in radiation health physics. Student demographic, graduation rates, the number of degrees awarded, and initiatives to promote diversity, equity, and inclusion over the last 20 years will be reviewed. Online education challenges in radiation health physics and solutions to overcome these challenges will also be discussed.

P.11  Poster Session   Simulation of ISO standard X-ray radiation field (N-120) using Monte-Carlo code MY Lee*, Korea Institute of Nuclear Safety

Abstract: The safety of industrial facilities using radiation generators can be evaluated by measuring the leakage radiation using radiation detectors. And the radiation detectors are calibrated using the standard Narrow beam X-ray field facilities built on the basis of ISO-4037.In this study, we simulated the X-ray radiation field(N-150) based on ISO 4037, using Monte-Carlo code. We simulated the X-ray source, intrinsic filter, additional filter, and X-ray tube using MCNP code. And we calculated X-ray energy spectrum, mean energy, first HVL and second HVL. As a result, the average energy was calculated as 100.8 keV, which showed a difference of 0.8% from the average energy presented by ISO(100 keV). In addition, the first HVL and the second HVL were calculated 1.74, 1.76 mm Cu, respectively, which showed a difference of 2.0% and 0.4% respectively from the HVL by ISO. The results of this study can be used to assess the safety of industrial facilities using radiation generator using MCNP code.

P.12  Poster Session   NRC Research to Inform Protective Action Strategies TR Smith*, U.S. Nuclear Regulatory Commission

Abstract: The U.S. Nuclear Regulatory Commission's vision is to demonstrate the Principles of Good Regulation (independence, openness, efficiency, clarity, and reliability) in performing our safety and security mission. The agency puts these principles into practice consistent with our organizational values and our open, collaborative work environment. Emergency preparedness (EP) regulations have evolved to a more technology-inclusive, risk-informed, performance-based, and consequence-oriented framework. At the same time, the agency is also working on a vision and strategy for the use of technologies like artificial intelligence and digital twins in meeting our mission. Consistent with this vision, the NRC has embraced innovative approaches, new and diverse ideas, and an environment of collaboration in efforts to enhance EP. This poster presentation will provide an overview of how the NRC is collaborating with and creating opportunities for nuclear engineering students to learn about EP and Health Physics (HP) and explore the use of new technologies. The poster will highlight the valuable contribution of students in creating innovative solutions to challenging design projects related to radiological emergency preparedness and incident response.

P.13  Poster Session   NRC Research to Inform Protective Action Strategies TR Smith*, U.S. Nuclear Regulatory Commission

Abstract: Protective actions are designed to avoid or reduce dose from exposure to radioactive materials. The choice of protective action includes evacuation, sheltering, and the use of potassium iodide as a supplement to these actions. For nuclear power plant emergencies, protective action strategies are based primarily on consideration of large light water reactor technology. But as reactor technology evolves, and as our understanding of the risks and benefits of protective actions changes, our approach to protective action strategies needs to evolve as well. The NRC performs studies to ensure our regulations and guidance continue to reflect the current state of knowledge. NRC studies also provide insights and identify best practices of benefit to response agencies. These studies include: 1) a study of offsite response organization capabilities and practices in the intermediate phase of an emergency, 2) a state-of-the-art study using microscopic traffic simulation models to better understand evacuation dynamics, 3) studies to quantify the benefit of shelters and masks, and 4) consequence analysis studies that provide insight into the basis for protective action strategies. This poster will provide an overview of NRC work to support development of effective protective action strategies for public health and safety.

P.14  Poster Session   Putting Our Vision into Focus: NRC Collaboration to Enhance Emergency Preparedness TR Smith*, U.S. Nuclear Regulatory Commission

Abstract: The U.S. Nuclear Regulatory Commission's (NRC) vision is to demonstrate the Principles of Good Regulation (independence, openness, efficiency, clarity, and reliability) in performing our safety and security mission. The agency puts these principles into practice consistent with our organizational values and our open, collaborative work environment. Emergency preparedness (EP) regulations have evolved to a more technology-inclusive, risk-informed, performance-based, and consequence-oriented framework. At the same time, the agency is also working on a vision and strategy for the use of technologies like artificial intelligence and digital twins in meeting our mission. Consistent with this vision, the NRC has embraced innovative approaches, new and diverse ideas, and an environment of collaboration in efforts to enhance EP. This poster presentation will provide an overview of how the NRC is collaborating with and creating opportunities for nuclear engineering students to learn about EP and Health Physics (HP) and explore the use of new technologies. The poster will highlight the valuable contribution of students in creating innovative solutions to challenging design projects related to radiological emergency preparedness and incident response.

P.15  Poster Session   A Day in the Life of a HOO HT Crouch*, U.S. Nuclear Regulatory Commission ; TR Smith, U.S. Nuclear Regulatory Commission

Abstract: The U.S. Nuclear Regulatory Commission (NRC) responds to events involving facilities or material we license, when public health and safety could be affected. The NRC's incident response program relies on our Headquarters Operations Center (HOC) in Rockville, MD, and four Regional Incident Response Centers throughout the country. The agency's response provides expert consultation, support, and assistance to State and local public safety officials responding to the event. The NRC’s HOC is the nerve center of Headquarters radiological emergency response activities. A team of Headquarters Operations Officers (HOOs) and Headquarters Emergency Response Officers (HEROs) stand ready 24 hours a day, 7 days a week, 365 days a year to receive reactor and materials event reports from licensees and agreement states, as well as other information. The HOC further disseminates the reports received to applicable NRC Regions, partner Federal agencies, and other stakeholders as needed. An important function of the HOOs on duty is to monitor and maintain communications with licensees during events, drills, and exercises to ensure effective communication flow. This poster will provide a snapshot into a day in the life of NRC HOOs and HEROs, how the HOC operates, and the tools used to respond to real-world incidents and exercises.

P.16  Poster Session   NRC Rulemaking on Emergency Preparedness RD Fisher*, U.S. Nuclear Regulatory Commission ; TR Smith, U.S. Nuclear Regulatory Commission

Abstract: The U.S. Nuclear Regulatory Commission (NRC) is preparing for the future of nuclear power, which includes a graded approach to emergency preparedness (EP) as the final layer of a robust defense in depth strategy to protect public health and safety. As large light water reactors have begun to shut down after decades of safe operation, the NRC developed a proposed rule for power reactors transitioning to the decommissioning process including a risk-informed graded approach to EP as the radiological risks decrease over time. But even as the early generation of reactors are ending operation, the future of small modular reactors, advanced reactors, and other new technologies is here. As part of its safety and security mission, the NRC has prepared a final rule on emergency preparedness for small modular reactors and other new technologies. This draft final rule takes a transformational approach and provides an alternative performance-based, technology-inclusive, risk-informed, and consequence-oriented framework for EP. And the agency has started the work on the regulatory framework for advanced reactors and fusion technologies. But while emergency preparedness continues to evolve, the NRC's mission, values, and principles of good regulation remain the grounding forces for the agency in order to ensure that the public’s health and safety is maintained. This poster will provide updates on NRC rulemaking activities related to emergency preparedness.

P.17  Poster Session   Internal Dosimetry of Cu-64 in a Computational Tumor-Bearing Mouse Model PK Witter*, Colorado State University ; A Brandl, Colorado State University; JJ Bell, Colorado State University

Abstract: The radiopharmaceutical Copper-64 diacetyl-bis(N4-methylthiosemicarbazones) (64Cu-ATSM) has rising clinical interest as a theragnostic agent; that is, one that can be used as both a diagnostic tool and a treatment for certain forms of disease. The ATSM ligand selectively distributes to hypoxic tissues, often difficult targets for chemotherapy and radiotherapy cancer treatments. The copper radionuclide detaches from the ligand in the reducing environment, at which point the unique decay scheme of 64Cu offers multiple imaging and clinical pathways. A Monte Carlo N-Particle (MCNP) radiation transport code assessment of absorbed fractions and absorbed dose to major organs was carried out using an anatomically accurate voxelized phantom of a tumor-bearing mouse. In decay scenarios in which the organ of interest was the source organ, approximately 60% of the total energy transferred from a 64Cu decay came from the beta decay, approximately 30% from the positron decay, and approximately 1% from the Auger electrons. The contribution of each decay mechanism to the absorbed dose in organs where the decay did not take place depended on the proximity of the target organ to the source organ. These results were used in conjunction with 64Cu-ATSM biodistribution data from two published mouse studies to estimate organ and whole-body absorbed doses from administered activities. The differences in organ absorbed doses between the studies shows the mouse model variances that can impact dose and lead to variability in dose-response curves down the line. A computational model allows for a better understanding of the organ-specific doses and should be considered in the development of future studies assessing the theragnostic properties of radiopharmaceuticals in translational models.

P.18  Poster Session   Radioactivity in Selected Fertilizers and their Radiological Health Implications B Billa*, Mississippi School for Mathematics and Sciences ; M Beitollahi, University of Utah; C Nettles, Mississippi School for Math and Sciences; S Adzanu, Alcorn State University; J Adjaye, Alcorn State University

Abstract: Fertilizers are part of farming industry and they play a major role in improvement of plant growth and enhancement of crop yields. One of the essential elements, potassium, helps in root growth and drought resistance of plants. Depending on soils fertility, farmers tend to provide potassium in the form of potash fertilizer which is derived from potash rock cored from earth’s crust. Rocks derived from the earth’s crust consist of trace quantities of Naturally Occurring Radioactive Materials (NORM) and NORM concentrations significantly vary based on rock type, geographical location, and concentration of the rock. Potash is a commonly used fertilizer derived from potash rock and to increase concentration of potassium, manufacturers increase percentage of potash which can eventually enhance radioactive concentrations (specifically K-40) in fertilizers. To exactly estimate and experimentally verify the levels of radioactive K-40 in selected fertilizers (0-0-60), a study was performed on fertilizers available in local market. K- 40 was theoretically estimated by considering the half-life; molar mass; and decay constant while experimental studies were carried out by performing gamma-spectroscopy. Obtained results for radioactivity concentrations of K-40 from theoretical estimation and gamma spectroscopy are 15, 110 and 15, 162 Bq kg-1 respectively. Results suggest that both experimental and theoretical K-40 values are compatible. Further, obtained results are compared to average K-40 concentration in soils within the US. Lastly, radioactivity based radiological health hazard indicating parameters are computed. Results indicated that radiological health hazards to living organisms from potassium enhanced fertilizers considered in this study are significantly higher to the world-wide averages of health hazard indicating parameters. This study strongly suggests that it is imperative that stringent recommendations are developed in handling and usage of these radioactivity enhanced materials.

P.19  Poster Session   Radioactivity Studies on Local Catfish D Dominic*, Alcorn State University ; M Beitollahi, University of Utah; J Billa, Alcorn State University; S Adzanu, Alcorn State University; J Adjaye, Alcorn State University

Abstract: Being part of surface water based resources, fish tend to uptake various elements/pollutants (if present) that may have been naturally or artificially (due to man-made activities) present in soils and water bodies. Levels of these pollutants could be impacted by factors such as size of the fish, naturally present elements in soils and water, and more importantly presence of man-made activities in the vicinity of water bodies. In this context, fish native to lower Mississippi region – Channel catfish (Ictalurus punctatus), are collected and analyzed using a 35% efficient solid-state detector for man-made and naturally occurring isotopes. For a better understanding, 10 fish samples from local catfish farms were collected and analyzed for man-made and naturally occurring isotopes. Doses resulted from consumption of catfish (River catfish and farm catfish) are estimated considering the levels of experimental radioactivity values. Results suggested presence of trace quantities of naturally occurring radioactive materials in both sets of catfish. As there are many human/industrial activities carried out along the Mississippi river, similar studies must be performed on an ongoing basis as there may be accidental releases from these industries into the river and the fish can uptake these wastes. The overall goal is to assess the doses from consumption of local fish and compare the obtained doses to the Nuclear Regulatory Commission (NRC) recommended safety dose levels for the public.

P.20  Poster Session   Toxicological Considerations of Tungsten and Depleted Uranium Exposure using Biokinetic Models L Keifer*, Georgia Institute of Technology ; EM Mate-Kole, Georgia Institute of Technology; D Sundberg, Georgia Institute of Technology; SA Dewji, Georgia Institute of Technology

Abstract: Both pure tungsten and depleted uranium (DU) are employed extensively in military and industrial settings. When alloyed with other metals such as nickel, titanium, and cobalt, these compounds exhibit increased hardness and durability, making them optimal for incorporation in munitions and vehicle armor. Upon impact, up to 70% of heavy metal ammunition fragments aerosolize and contact the lungs of affected personnel, leading to tumorigenesis in the bone and lungs and lung fibrosis. Such pathological health changes in military and factory workers and rodent models are observed primarily following chronic exposure (upwards of 12 months), raising concerns about the toxicity of tungsten and DU compounds. Additionally, further research has confirmed toxicological dependence on chemical factors such as solubility and compound identity, citing amplified effects in the presence of soluble tungsten carbide-cobalt and uranyl ion and halide compounds. The goal of this study was to investigate contemporary knowledge surrounding absorption and toxic effects of tungsten and DU alloys in the respiratory tract and other systems as distributed via systemic circulation, demonstrating the applicability and limitations of biokinetic models from realistic heavy metal inhaled source forms. Considerations were made that discuss chemical properties of inhaled metals via a parametric sensitivity analysis of biokinetic models input, transfer rate, and excretion data. Due to limited available data, the conclusion of this analysis has conveyed the necessity for additional in vivo and observational studies that more conclusively establish a relationship between industrial heavy metal compounds and adverse health conditions. Future work will investigate the deposition profile of custom source forms via computational fluid and particle dynamics modeling to predict the deposition profile, refine biokinetic models, and evaluate correlations with fibrosis endpoints.

P.21  Poster Session   Radiation Protection Considerations for Cancer Patients with End-Stage Renal Disease Receiving 131I Treatment M Louis*, Georgia Institute of Technology ; EM Mate-Kole, Georgia Institute of Technology; L Aziz, Houston Methodist; SA Dewji, Georgia Institute of Technology

Abstract: Evaluation of the current patient release guidelines, as given in U.S. Nuclear Regulatory Commission (NRC) Regulatory Guide 8.39 Rev. 1, for end-stage renal disease (ESRD) patients receiving radioiodine (RAI) ablative therapy has yet to be addressed. In clinical practice, many clinicians have resorted to individualized RAI therapy using patient-specific dosimetry, necessitating biokinetic modeling for patient release considerations in patients with comorbidities. In this study, a biokinetic model for I-131 in ESRD patients on dialysis has been developed, improving on traditional simplified compartmental models, reflective of kinetics from multi-compartment models with updated transfer coefficients modified to reflect the different physiological functions of compartments. To determine a comparison via the NRC Reg. Guide 5 mSv criteria, effective dose rate coefficients were computed by combining updated biokinetic model with a Monte-Carlo radiation transport calculation of stylized computational hermaphroditic phantoms. The computed dose coefficients from ESRD patients were then compared to the dose rates generated for point-source models of NRC Reg Guide 8.39 Rev. 1 (and the proposed methodology in Rev. 2). From the results obtained, the baseline models of Rev. 1 and Rev. 2 depicted overestimation of the effective dose rate to an exposed individual for the time immediately post-administration, and both models overestimated the total dose to the maximally exposed individual. However, the application of various patient specific modifying factors to the Rev. 2 model resulted in an overestimation by only a factor of 1.25. Overall, the results produced with the patient-specific modifications provide improved convergence with the dose rate coefficients computed in this study for ESRD patients. The study thus demonstrates the utility and impact of incorporating realistic biokinetic models for consideration in developing patient release guidelines for radionuclide therapies.

P.22  Poster Session   Lens Dose Reduction in Image-Guided Radiation Therapy Using Cone Beam Computed Tomography T Taniguchi*, Asahi University Hospital ; K Adachi, Asahi University Hospital; S Nakaya, Asahi University Hospital; R Asahi, Asahi University Hospital; M Matsuo, Gifu University

Abstract: Cone beam computed tomography (CBCT) image navigation allows precise radiation delivery to the target area during radiotherapy using a linear accelerator. However, using CBCT during every radiation treatment increases treatment dose. Thus, increased radiation dose to the highly radiosensitive lens is a concern. Therefore, we optimized the CBCT imaging parameters of the head to reduce the lens dose. First, CBCT mounted on a linear accelerator was used to scan a head phantom with dosimeters placed in the lens area. Subsequently, the head CBCT was scanned with a rotation of 200°, and the impact on lens dosage was measured by altering the starting position of rotation. Other than changing the scanning angle, no other parameters were altered. Measurement of the lens dose showed that the highest dose reduction was achieved when scanning was performed at a 200° clockwise rotation from an imaging start angle of 70°. Consequently, the dose is reduced from the CBCT system’s default level by approximately 60%. CBCT is important for determining the imaging angle at which the direct X-ray beam enters the lens the least. Thus, our study has revealed a method of dose reduction for highly radiosensitive organs in high-precision radiotherapy of the head.

P.23  Poster Session   Test and comparison of two extremity dosimetry systems based on BeO and Al2O3 LY Chen*, Mirion Technologies ; FY Hsu, National Tsing Hua University

Abstract: Ionizing radiation is used in many industries, and the characteristics of the various operations vary widely. Personal dosimetry, which mainly monitors effective doses in the past, may not be sufficient to meet the actual needs of various industries; for example, radiologists and pharmacists who perform nuclear medicine operations will receive far more doses to their extremities than other individual organs. The eyes of physicians engaged in interventional diagnosis and treatment will also receive higher radiation doses. Therefore, in order to strengthen the monitoring of extremities and eye lens doses, and follow the reduction of the dose limit in response to ICRP-118 recommendations; this study used Al2O3 and BeO that meet the characteristics of personnel dose requirements for the design of extremity dose systems, and tests include energy dependence, Angle dependence, minimum measurable value, etc., and test with reference to ANSI/HPS N13.32. The test results showed that the Al2O3 system with double-layer design has good radiation discrimination ability, but the error caused by angular dependence was large (due to the influence of double-layer design); BeO had good results in energy dependence, but when the radiation source was unknown, the difference in response to photons and electrons can cause large errors.

P.24  Poster Session   A Novel Calibration Phantom Used with a Basic Portable GM Detector to Monitor for Internal Radiation Exposure H Datz*, Soreq Nuclear Research Center, Israel. University of Cincinnati, Cincinnati, Ohio. ; O Aviv, Soreq Nuclear Research Center, Israel.; H Spitz, University of Cincinnati, Cincinnati, Ohio.

Abstract: A novel phantom has been developed to calibrate a basic portable GM detector that can be used identify persons who have may have sustained internal exposure to a radioactive material following a radiological event. The phantom simulates the torso of a person who is bent over the probe of a GM detector placed against their abdomen. The response of the detector is evaluated using radioactive sources distributed within the phantom to simulate contamination in the respiratory and gastro-intestinal tracts. This quick-sort method would be useful following a radiological event in developing countries where resources and radiation detection equipment is limited. The response of a Ludlum Model 133 series GM detector was evaluated using the phantom containing multiple sources of 137Cs inserted at various locations in the phantom. Results suggest that it is possible using basic portable survey instruments rapidly monitor a population for internal exposure to radioactive materials.

P.25  Poster Session   Occupational Dose Reductions During FDG Administrations at Memorial Sloan Kettering Cancer Center DA Bierman*, Memorial Sloan Kettering Cancer Center ; M Williamson, Memorial Sloan Kettering Cancer Center; D Miodownik, Memorial Sloan Kettering Cancer Center; B Quinn, Memorial Sloan Kettering Cancer Center; H Schöder, Memorial Sloan Kettering Cancer Center; S Davie, Memorial Sloan Kettering Cancer Center

Abstract: Background: Cumulative staff dose at Memorial Sloan Kettering Cancer Center (MSK), an NCI-designated Comprehensive Care Center with a main campus located in New York City and multiple outpatient facilities across New York City and the surrounding metropolitan area, was increasing with the rising volume of PET/CT diagnostic procedures using F-18 fluorodeoxyglucose (FDG). Prior to 2019, these procedures utilized unit doses of approximately 12 mCi each. To counter the increase in staff dose, automatic infusion / injection systems were implemented in Quarter 4-2019 at 8 sites performing FDG administrations; one system each at sites 1 through 7 and two systems at main campus. This study examines the impact of the automatic infusion / injection systems on occupational exposure for their first two full years of operation across the MSK network. Methods: The number of PET patients and the total annual activity of FDG administered was obtained from MSK’s nuclear medicine information system (NMIS, ec2 Software Solutions, Somerset, NJ) for sites 1 through 7 and main campus from 2017-2021. Annual staff dose for this period was obtained from dosimetry records for employees administering or handling FDG (Nuclear Medicine Technologist, Nuclear Medicine Nursing, Nuclear Pharmacy, Nuclear Medicine Physician). The results for each year were converted into a rate of millirem per PET patient (mrem/PET Ptn) to account for any variances in procedure volume by site. Results: At sites 1-7, which perform FDG PET infusions, the average whole-body mrem/PET Ptn fell from 0.92 mrem/PET Ptn before the Q4-2019 intervention to 0.57 mrem/PET Ptn for 2021. Extremity results fell from 2.89 mrem/PET Ptn to 0.49 mrem/PET Ptn over the same period. The number of ALARA-1 investigations also fell from 45 to 39 and the average dose per ALARA-1 decreased by 15% to 159 mrem/ALARA-1. For Main Campus, which performs other radiopharmaceutical procedures, the average mrem/PET Ptn for Nuclear Medicine Technologists and Physicians fell from 1.5 mrem/PET Ptn in 2019 to 0.5 in 2021. For the same period the rate fell from 1.09 mrem/PET Ptn to 0.22 and 0.32 mrem/PET Ptn to 0.21 mrem/PET Ptn for Nuclear Medicine Nurses and Nuclear Pharmacy respectively. The number of ALARA-1 investigations for Main Campus Nuclear Medicine decreased from 37 to 1 for the same period with a 25% reduction for the average ALARA-1 to 162 mrem/ALARA-1. Conclusion: Automatic infusion / injection systems for FDG administrations can favorably impact occupational dose as observed at MSK and as demonstrated in the published literature.

P.26  Poster Session   Shielding Study of a Miniature Klystron Emitting 60 keV Electrons S Adadi*, Georgia Institute of Technology, Stanford Linear Accelerator Laboratory ; T Frosio, Stanford Linear Accelerator Laboratory, U.S. Department of Energy, Office of Science; M Santana, Stanford Linear Accelerator Laboratory, U.S. Department of Energy, Office of Science; B Shirley, Stanford Linear Accelerator Laboratory, U.S. Department of Energy, Office of Science; BR Weatherford, Stanford Linear Accelerator Laboratory, U.S. Department of Energy, Office of Science; SA Dewji, Georgia Institute of Technology

Abstract: This study aims at designing the shielding required to safely operate a miniature experimental klystron with a planned operation of at 60 kV, 0.055 mA at 10 Hz with a pulse length of 1 µs. Electrons will be produced from the klystron electron gun, and then proceed along a path through the copper tube before finally reaching the copper collector where the beam is terminated. A shielding analysis was performed to comply with the 10 CFR Part 835 indicating a limit of 0.05 mrem per hour at 30 cm from the source. Prior to conducting simulations, several structural weak points were determined by considering parameters such as the material composition and thickness of each region. The density and electron stopping power of all materials are substantial, suggesting that there will be no accumulation of electron dose outside of the device. However, when additionally considering low-energy secondary photons generated through processes such as bremsstrahlung and Compton effect with high current density, the material compositions and thicknesses in the device may not provide adequate shielding. Loss of electrons at any stage of the beam pathway may result in the emission of X-rays as bremsstrahlung. The Monte Carlo radiation transport code, FLUKA, was employed to simulate the klystron, with associated challenges of obtaining sufficient convergence statistics in the Monte Carlo simulations from low energy photon physics. Secondary photons exiting the klystron device were responsible for high doses when particle currents were high. Dose rates were analytically calculated for up to approximately 900 rem per hour at some of the identified weak points, which contrasted with FLUKA simulations. Therefore, the photon dose energy spectrum was scored at strategic locations representative of the worst-case scenario in the identified weak points. Energy-dependent spectra were employed as sources to compute energy-dependent attenuation laws, providing more reasonable shielding requirements. The results of this study were demonstrated to be of relevance in the design and construction of future mini klystrons and contribute to the improvement of safety protocols for similar devices. The findings can also serve as a reference for other shielding requirements for low energy / high current devices and help to advance the field of radiation safety.

P.27     Simulation study on radioactive contamination mapping for emergency responder safety J. Lee*, Korea Institute of Nuclear Safety ; Kim, Korea Institute of Nuclear Safety

Abstract: Radioactive contamination emergencies pose significant risks to public health and safety, as well as to the health and safety of emergency responders. Accurate measurement and mapping of surface radioactive contamination are essential for supporting decisions about protective measures in these situations. In this study, we used the Monte Carlo method to design and simulate various types of contamination, and applied different measurement methods and mapping algorithms to create radioactive contamination maps. We evaluated the similarity between the designed contamination and mapped contamination, and used this information to optimize measurement and mapping approaches. Our findings suggest that by creating more accurate information through optimized measurement and mapping, exposure of the public and emergency responders can be minimized. We discuss the potential for artificial intelligence learning and the creation of new mapping algorithms to further improve the accuracy of measurement and mapping in emergency situations. Our study highlights the importance of accurate measurement and mapping in supporting important decisions for protective measures in radioactive contamination emergencies.



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