MPM-E - Special Topics in Health Physics Baltimore 3 14:30 - 17:30
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| Chair(s): Daniel Strom
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MPM-E.1
14:30 Spectroscopic Particulate, Iodine, and Noble Gas Monitor with Continuous Unattended Operation and Analysis JK Zickefoose*, Mirion Technologies (Canberra) Inc
; F Bronson, Mirion Technologies (Canberra) Inc; E Dang, Mirion Technologies (Canberra) Inc; B Huckins, Mirion Technologies (Canberra) Inc
Abstract: A spectroscopic air monitoring system for continuous measurement of particulates, iodines, and noble gasses has been designed and constructed. The design is based on a series of filter paper and charcoal absorbers placed in close proximity to an HPGe detector that is then surrounded by an anulus shaped gas chamber. Continuous acquisition is accomplished with novel software/hardware, the Mirion Data Analyst, which allows for unattended acquisition, analysis, and storage of data over multiple workflow definitions. Each workflow definition may be configured for separate averaging intervals, such as 1 minute or 60 minutes, where different analysis settings or even analysis algorithms may be chosen for a single data stream. Since multiple averaging times are allowed for a single data stream, it is possible to attain both swift reaction times as well as low minimum detectable concentrations. The Data Analyst also stores and applies energy, shape, and efficiency calibrations such that analysis results are provided in either activity concentration or activity release rate. The system stores all analysis results as well as the acquired spectra on a host computer, where current or historical data may be reviewed. Derived quantities such as the differential activity deposited on one of the filters is computed from the comparison of two consecutive measurements. This process is also handled by the data analyst. The hardware/software aspects, system performance, and calibration methodology will be discussed.
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MPM-E.2
14:45 Aerospray: What Covid-19 Research Teaches HPs about Managing Intakes DJ Strom*, Washington State University
Abstract: Airborne viruses are mostly not aerosols but are “aerospray,” droplets that are sprayed into one’s breathing zone that don’t travel far or remain suspended for long. Droplets can be generated by turbulent air flow and bubbles bursting on air-fluid surfaces and emitted from the human respiratory tract by coughing, sneezing, singing, talking, and breathing. Unlike airborne radioactive materials, virus aerospray almost always originates from human respiratory fluids. Airborne radioactive materials can be solid, liquid or gas/vapor, but active viruses are only found in moist environments and are inactivated when dry. Surgical masks are first and foremost emission controls, not PPE, so the most important mask is the one on the other guy! When everybody correctly wears masks, everybody’s protection increases because emissions are dramatically reduced. Healthcare facilities require you to wear a mask because they regard you as the source. Universal precautions adopted by healthcare workers are used not to protect against 1- or 5-um AMAD aerosols, but from patients emitting AIDS, hepatitis or other aerosprays. The probability of finding 1 or more virus particles in a droplet is a function of droplet diameter and virus titer (# virions per mL); except for rare, extremely high titers, 1- and 5-um aerosol droplets generally contain zero virions. Sigmoid or Weibull dose-response relationships for viruses are characterized by a median infectious dose (1440 virions for the original 2019 SARS-CoV-2 variant). Masking and distancing, as well as holding one’s breath and staying upwind when possible, make risk ALARA by reducing the probability of becoming infected. Exposures to aerospray are reduced by covering or aiming one’s cough/sneeze, as well as by increased distance from the aerospray source. When engineered controls on the source are not adequate, masks are used as PPE, where protection from smaller particles decreases with less effective designs: PAPR > N-95 > KN-95 > surgical mask > bandana. New variants have lower infectious doses because of enhanced ability to evade the immune system; this makes ALARA more important than ever. False things HPs and IHs say include “cigar smoke goes right through a surgical mask, so it does no good;” this speaker doesn’t understand importance of particle size both on inhalation and exhalation and ignores the fact tiny droplets rarely contain any virions at all. Complaints that there is no fit testing show that the speaker doesn’t understand a mask as emission control for aerospray.
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MPM-E.3
15:00 Review of Efforts in the Validation of the TRDS for the Location of Metlino M Hiller*, CheMin GmbH
; C Woda, bfs; B Napier, PNNL
Abstract: In the years 1949–1956, the Mayak plutonium facility in the Southern Urals, Russia, discharged radioactive effluent into the nearby the Techa River. Consequently, residents of villages along the Techa River were exposed to significant levels of radiation and elevated levels of cancer in follow-up studies. To be able to relate the excess cases to a radiation risk, a dosimetry system called Techa River Dosimetry System (TRDS) is used. For a precise relation between dose and risk, a precise and valid dosimetry system is of importance.
Validation of the models underlying the TRDS with independent experimental methods is an important task. One possibility is to use ceramic building materials such as bricks as a dose archive in settlements, which can be readout with luminescence techniques to determine the absorbed dose in brick due to the environmental radioactive contamination. Over the past 10+ years, the authors made large efforts made to validate the TRDS for the location of the former village of Metlino, only 7 km downstream from the release site.
This presentation reviews previous validation efforts made during the SOLO and SOUL projects funded by the European Union and the JCCRER project funded by US DOE. It will be shown how the dose reconstruction studies allowed to describe the dose distribution in Metlino. Work on validation was still ongoing, yet, the project came to halt in 2022 and funding ceased. Missing pieces in the puzzle of the reconstruction and the efforts that would be needed to get a final picture will be discussed.
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MPM-E.4
15:15 Dose Assessments from Multiple Tritium Release Scenarios During the Tritium Systems Demolition and Disposal Project at the Princeton Plasma Physics Laboratory G Ascione*, Princeton Plasma Physics Laboratory
; JL Malo, Princeton Plasma Physics Laboratory; CR Ferguson, Longenecker & Associates, Inc.; RS Sheneman, Princeton Plasma Physics Laboratory
Abstract: The Princeton Plasma Physics Tokamak Fusion Test Reactor (TFTR) operated for 15 years, from 1982 to 1997. From November 1993 to April 1997 over a million curies of tritium was used to fuel Deuterium Tritium (D-T) experiments, leaving the reactor and tritium systems in an activated and contaminated state. In 2002 PPPL completed a successful D&D project focusing on the TFTR reactor removal, leaving the tritium storage and delivery systems in place for future use. In 2021 PPPL initiated the Tritium Systems Demolition and Disposal (TSDD) project to remove all the remaining tritium systems from the facility. An inventory of more than 18,000 Curies of tritium was largely deposited on three molecular sieve beds. In preparation for the removal and disposal of the tritium systems dose calculations were performed simulating worst case atmospheric and ground releases scenarios of the full inventory of tritium on-site. The data was used to support a graded approach in assigning several DOE approved credited controls during the TSDD project. The results of four separate accidental releases of tritium will be presented.
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MPM-E.6
16:00 Dose and Risk Assessment for Faculty and Students Studying in a CS-137 Contaminated Building. TC Chao*, Chang Gung University
; NC Tien, National Tsing Hua University; TK Yeh, National Tsing Hua University; CY Lin, Chang Gung Memorial Hospital
Abstract: The purpose of this study is to assess dose and risk for faculties and students in a Cs-137 contaminated building. These results will be evaluated by peers and field experts to recommend whether further detailed epidemiological studies should be conducted. National Tsinghua University's Biotechnology Building was contaminated with Cs-137 when it was built in 1978. In 2012, NTHU carried out a contamination detection in the whole building, and measured some point and average dose rates in each space. As for the exposure to faculties and students, it is urgent to use statistical methods to verify if these doses could cause statistically significant cancers. The purpose of this study is to explore the feasibility of using "a detail epidemiological method to investigate the risk of radiation to exposed teachers and students". Due to the many uncertainties in risk assessment, similar studies require tens of thousands to millions of people exposed, and there are only about 600 people exposed in this NTHU accident, no mention that the measured dose is relatively low. Whether it can provide statistically significant conclusions is the focus of the feasibility study. This preliminary study is to evaluation the pros and cons of conducting a detail epidemiological study, and serve as a reference for the next step. The research approaches are quantitative which uses the nominal risk coefficient and the prevalence of cancer in Taiwan to assess the absolute risk of the exposed population, and compare it with the prevalence of cancer in Taiwan. Different tests will be implemented to find significant differences, or finally to estimate the number of cases required to achieve a significant difference.
The exposure doses received by the teachers and students of the NTHU are very low. Taking the advanced dose reconstruction as an example, the average cumulative dose is .478 mSv, and the maximum value is 4.205 mSv, because the exposed people have stayed in the center for 2-17 years, it can be seen that There is little difference between the annual dose and the background value. The calculated ERR takes the maximum value as an example, which is ERR=0.0003607 for male lung cancer, because the incidence rate of male lung cancer in 2018 is only 81.2 per 100,000 people, and the risk after exposure increase only 4/1000, still at 81.2.
In order to achieve 80% power ( 1-β=0.8) and using two-sided 0.05-level test (α=0.05) to detect the risk of exposure to the maximum ERR (ERR=0. 0003607), the exposure group required The sample size is 81.6 billion people, and the non-exposed sample size is 816.2 billion people. However, there are only 636 people exposed in this case, and the population of Taiwan is only 23 million. Under such a low dose, it is not enough to produce statistics significant results.
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MPM-E.7
16:15 ISOE ALARA Global Program Accomplishments & Future HP Studies D. Miller*, North American Technical Center
; Da Miller
Abstract: The USA operating nuclear reactors play an important role in providing carbon-free electric generation to the public. Since 1993, the North American Technical Center has conducted annual occupational dose studies for US, Canadian, and Mexican RP management and ALARA staff to support safe and efficient operations and refueling outages.
The presentation discusses 30 years of radiological engineering studies to analyze source term reduction, radiation instrumentation, AI, robotics, and ALARA OE lessons learned. The Information System on Occupational Exposure (ISOE) was established by OECD Nuclear Energy Agency (Paris) and later IAEA (Vienna). ISOE has four Technical Centers including European (Paris), IAEA (Vienna) and Asian (Tokyo), and North American (University of Illinois). The North American Center annually collects and inputs ALARA dose data from PWR, BWR, and CANDU outages into the global ISOE database. HP and NE undergraduate and graduate students participated in performing the radiological engineering analysis of dose trends in North America and provide reports to Station ALARA Committees. Over 24 NATC analysts have completed NATC assignments and 80% are engaged in professional employment at nuclear plants or regulatory agencies.
The presentation discusses recent NATC studies including drone entry to BWR Drywell at power to locate steam leaks, removal of colloids from coolant systems to achieve industry-low outage doses, Big Data analysis of 1000s of RWPs and work orders from 20 refueling outages to identify optimum performances as a future refueling ALARA planning aid.
NATC conducts an annual ALARA Symposium to share solutions to RP problems and highlight good practices. The Symposia showcases the annual World Class ALARA Performance, RP Professional of the Year, and Outstanding ALARA Innovation Awards based on selection by peer RP managers. The awards are used for global ISOE information sharing and to mentor young health physicists in good RP practices and the use of new technology. The US NRC Commissioner and the CNSC VP and Chief Scientist provided plenary addresses at the January 2023 NATC ALARA Symposium: The 30th Anniversary of the ISOE Program.
This presentation summarizes some of the latest new RP ALARA applications including pixelated, 3D CZT new technology at nuclear plants mapping, medical 3D imaging, homeland security surveillance, and decommissioning site isotopic characterization. The CZT detection system provides GPS location and digital camera color-coding of individual isotopic identification.
The CZT system was developed by the University of Michigan over 22 years of extensive research. NATC beta-tested the new technology in 2014 at the D. C. Cook Nuclear Station. Seventy CZT monitors have been employed at nuclear plants globally. The North American Technical Center’s ALARA network program has provided information on new applications and lessons learned with the new technology. The CZT system has been successfully used to verify the adequacy of temporary shielding installed for refueling outages, contamination control, PWR CRUD burst isotopic mapping, and radwaste shipment surveys.
The system allows room-temperature applications for process lines to accurately measure isotopic characterization without the delay of sample line collection and chemistry laboratory analysis. The use of the new spectra CZT system at Palisades is discussed including the new discovery of significant Ag-110m coolant line contamination.
The IAEA has selected the pixelated, 3D CZT system for the IAEA safeguard inspectors based on comparisons of available similar isotopic characterization instrumentation. Position-sensitive, 3-dimensional CZT semiconductor gamma-ray spectrometers and imagers have been designed and are now in university medical research laboratories for applications for PET and radionuclide patient isotopic imaging including 100 CZT detector systems. The CZT spectra detectors are being evaluated to use as contamination surveillance monitors on SMRs for the University of Illinois micro-reactor.
Finally, a discussion of lessons learned on the replacement of plant-wide radiation monitoring systems is provided. This NATC initiative supports the continued operation of US BWRs and PWRs for an additional 20 to 40 years. (Details of the NATC ALARA new technology will be available on the NATC Website.)
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MPM-E.8
16:30 Identification of novel biomarkers of radiation exposure using four different species M Sproull*, NIH/NCI/ROB
; D Nishita, SRI; P Chang, SRI; M Moroni, AFRRI; D Citrin, NIH/NCI/ROB; U Shankavaram, NIH/NCI/ROB; K Camphausen, NIH/NCI/ROB
Abstract: Purpose: There is a need to identify biomarkers of radiation exposure for use in development of blood diagnostic biodosimetry assays for radiological accidents and for clinical use as markers of radiation injury. Most research approaches for biomarker discovery rely on a single animal model. The current study sought to take advantage of a novel aptamer-based proteomic assay which has been validated for use in many species to characterize changes to the blood proteome after total body radiation exposure across four different mammalian species including humans.
Methods: Plasma was collected from C57BL6 mice, Sinclair minipigs, and Rhesus non-human primates (NHPs) receiving a single TBI exposure between 3.3 Gy to 4.22 Gy at 24 hrs post exposure and from human patients receiving a single 2 Gy TBI dose 6 hours post exposure. Plasma was screened using the Somalogic SOMAscan assay to evaluate changes in the expression of 1,310 protein analytes. Confirmatory analysis of biomarker HIST1H1C expression was completed using plasma from C57BL6 mice receiving a 2, 3.5 or 8 Gy TBI dose collected days 1, 3, and 7 post exposure by singleplex ELISA. Summary of key pathways with altered expression following radiation exposure across all four mammalian species was determined using Ingenuity Pathway Analysis (IPA).
Results: Detectable values were obtained for all 1,310 proteins in all samples included in the SOMAscan assay and a subset panel of proteins demonstrating significant (p < 0.05) changes in expression of at least 1.3 fold following radiation exposure were characterized for each species. IPA of significantly altered proteins yielded a variety of top disease and biofunction pathways across species with the organismal injury and abnormalities pathway held in common for all four species. The HIST1H1C protein was shown to be radiation responsive within the human, NHP and murine species within the SOMAscan dataset and demonstrated dose dependent upregulation at 2, 3.5 and 8 Gy at 24 hours post irradiation in a separate murine cohort by ELISA.
Conclusion: The SOMAscan proteomics platform is a useful screening tool to evaluate changes in biomarker expression across multiple mammalian species. In our study, we were able to identify a novel biomarker of radiation exposure, HIST1H1C, and characterize panels of radiation responsive proteins and functional proteomic pathways altered by radiation exposure across murine, minipig, NHP and human species. Our study demonstrates the efficacy of using a multispecies approach for biomarker discovery.
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MPM-E.9
16:45 RETROSPECTIVE EVALUATION OF CYTOGENETIC EFFECTS INDUCED BY INTERNAL RADIOIODINE EXPOSURE: A 27-YEAR FOLLOW-UP STUDY GK Livingston, REACTS CBL, ORISE
; TL Ryan, REACTS CBL, ORISE; MB Escalona, REACTS CBL, ORISE; AS Balajee*, REACTS CBL, ORISE
Abstract: Radioiodine (131I) is widely used in the treatment of hyperthyroidism and as an effective ablative therapy for thyroid cancer constituting 90% of the currently used therapies in the field of nuclear medicine. Increasing use of radioiodine in nuclear medicine warrants a detailed investigation on radioiodine induced biological effects either prospectively or retrospectively so that appropriate countermeasures can be taken to minimize the off-target effects. Here, we report the cytogenetic findings of a long-term follow up study of 27 years on a male patient who received two rounds of radioiodine treatment in 1992 and 1994 within a span of 26 months for his papillary thyroid cancer. Various cytogenetic endpoints such as Cytokinesis Blocked Micronucleus (CBMN) assay, Dicentric Chromosome Assay (DCA), genome wide translocations and inversions were assessed for the retrospective analysis. Frequencies of unstable and stable aberrations observed in the radioiodine patient were several folds higher than that of normal healthy individuals. In addition to balanced and complex chromosome translocations, clonal translocation involving chromosomes 14p;15q was also observed in the patient. Results of our 27-year retrospective study indicate that the past radioiodine exposure results in long lasting chromosome damage and that the persistence of translocations can be useful for both retrospective biodosimetry and for monitoring chromosome instability in the hematopoietic system of radioiodine exposed individuals.
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MPM-E.10
17:00 Time Dependence of the Neutrophil-Lymphocyte Ratio in the 1958 Y-12 Criticality Accident RE Goans*, MJW Corporation and REAC/TS
Abstract: During triage after a criticality accident or nuclear weapon event, it is important to decide whether each patient has a clinically significant dose (> 2 Gy) that would require referral for additional detailed evaluation and medical treatment. This is a binary decision, yes or no. The neutrophil to lymphocyte ratio (NLR) is such a decision parameter, is simple to obtain in field operations and is recognized in clinical medicine as an independent marker of systemic inflammation. A radiation accident database (12 criticality accidents with 29 patients; 23 gamma accidents with 32 patients) has been developed along with 125 normal controls. The decision threshold for NLR, optimizing both sensitivity and specificity, has been calculated using receiver operating characteristic analysis. This analysis has been applied to the 16 June 1958 liquid criticality event at the Y-12 facility in Oak Ridge. In this accident, eight individuals received mixed-field radiation doses of 0.29-4.61 Gy-Eq. Five patients experienced moderate to severe neutropenia and thrombocytopenia, consistent with the hematopoietic component of the acute radiation syndrome (ARS-H). All patients recovered with supportive care that was appropriate for 1958. Typically, the patients are divided into a high dose group (2.98-4.61 Gy-Eq) and a low dose group (0.29-0.86 Gy-Eq). The high dose group (3.9 ± 0.3 Gy-Eq; mean ± SEM ) can be considered as a model group for triage in a nuclear event where medical countermeasures would be considered. In this group, NLR is elevated above threshold for ~ 6 d, verifying its usefulness in the first week post-event as a triage instrument. However, considerable individual variation in NLR is noted.
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MPM-E.11
17:15 Long-term response of leukocyte counts in Rhesus Macaques with whole body irradiation Y Chino*, Colorado State University
; JD Olson, Wake Forest School of Medicine; JM Cline, Wake Forest School of Medicine; TE Johnson, Colorado State University
Abstract: The hematopoietic system is the most sensitive to radiation exposure. After acute ionizing radiation exposure, Leukocyte counts reach a nadir in a few days to several weeks post irradiation followed by recovery which takes from 4-8 weeks to a year. Accumulating evidence from A-bomb survivor, radiation therapy patient, and astronaut studies suggests ionizing radiation influences the hematopoietic system for more than a decade after the exposure. Compared to acute hematopoietic response, studies of long-term response and the mechanisms are limited. We analyzed the archival data of WBC differentials obtained from 8-17 year old Rhesus Macaques (Macaca mulatta). Nine animals had whole-body irradiation of 7.2-8.2 Gy at 3-4 years old. Twelve animals were age-matched controls with no radiation exposure. A CBC dataset was obtained during regular health checkups every 2-6 months during the study period. Linear mixed models for leukocyte, neutrophil, lymphocyte, and monocyte counts and their percentages were developed using R studio with R (ver. 4.2.2). Estimated marginal means calculated based on the models demonstrated statistically significant elevation in leukocyte and neutrophil counts and neutrophil% in irradiated animals compared to the controls. Lymphocyte% was significantly depleted in irradiated animals. Longitudinal trends for both control and irradiated animals were consistent with the trend of aging in hematopoiesis, which is described as skewed production of myeloid lineage cells such as neutrophils and monocytes than lymphoid cells. Longitudinal trends from irradiated animals suggested age-related increase in neutrophils and decrease in lymphocytes were stronger than in the controls, although the difference was not statistically supported. The mechanism of the long-term effects in hematopoietic system was not investigated in this study, but the result suggests ionizing radiation causes long-term effects to some of the factors that cause aging in hematopoietic system (i.e. aging in hematopoietic stem cell, elevated reactive oxygen species, and altered microenvironment of bone marrow), possibly induces early-onset or acceleration of aging in hematopoietic system. Extended analysis with observations including before and beyond the follow-up period in this study will be beneficial to understand the timeline and features of the long-term response.
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MPM-E.12
17:30 Radiation Protection Careers Initiative MB Lee*, Los Alamos National Laboratory
; J Billa, Alcorn State University; M Bonds, Universal Training and Testing Academy of America; S Adzanu, Alcorn State University
Abstract: Radiation Protection professionals are essential for radiological work and their positions are mission critical to the weapons programs at National Laboratories as well as maintaining the health and safety of workers, the public, and the environment. Radiation Protection professionals are in high demand due to extensive use and applications of radioactive materials and x-ray devices in other industries. Hiring managers at the National Laboratories and other related industries have struggled to fill available positions in Radiation Protection due to the stiff competition. In addition, it is recognized that there is a shortage of qualified professionals due to an aging workforce, the lack of awareness of career opportunities in Radiation Protection and the lack of training opportunities in Radiation Protection. This presentation discusses the development of the Radiation Protection Career Initiative and its accomplishments over the last five years.
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