Health Phys. Abstracts，Volume 120,Number 4

IdentificationofVolumeofDistributionfor239PuinRats

Madeline C.Cook, Richard R.Brey1

(1.Department of Health Physics, Idaho State University, 921 S 8th Ave, Pocatello, ID 83209)

Abstract:The work within identifies the volume of distribution(VD)of plutonium using data from studies in which rats were administered an intravenous bolus injection of239Pu4+-citrate.The research investigated two separate datasets.Data published by Durbin and colleagues in “Plutonium Deposition Kinetics in Rats” and studies conducted by Lovelace Respiratory Research Institute(LRRI)were examined.The goal of this research was to identify a value ofVDconsistent with the known biological behavior of plutonium.The identifiedVDis necessary to develop a physiologically-based pharmacokinetic(PBPK)model.The creation of a PBPK model describing the behavior of plutonium in the body enables the comparison of transfer rates to validate the biokinetic models currently in use for internal dosimetry purposes.TheVDof a substance describes the distribution between intracellular and extracellular fluid compartments, providing information such as cellular uptake and protein binding.TheVDtime profiles and values found using the Durbin data were consistent with known behavior of plutonium.TheVDvalues found using data provided by LRRI were not consistent with known behavior of plutonium; however, theVDtime profiles generated may still be of use for PBPK modeling.

Keywords:239Pu; dose assessment; dosimetry, internal; rat

Health Phys.120(4):367-377; 2021

SpectroscopyofRadiostrontiuminFuelMaterialsRetrievedfromtheChernobylNuclearPowerPlant

V.A.Zheltonozhsky1, M.V.Zheltonozhskaya2, M.D.Bondarkov3, E.B.Farfán4

(1.Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv, Ukraine;2.Lomonosov Moscow State University, Moscow, Russian Federation;3.State Scientific Research Institution “Chernobyl Center for Nuclear Safety, Radioactive Waste and Radioecology,” Slavutych, Ukraine;4.Nuclear Energy, Science and Engineering Laboratory, Kennesaw State University, Marietta, GA)

Abstract:Some basic methods of measuring radiostrontium activity by spectroscopic methods are considered in this study.These methods of assessing beta spectra and the characteristic radiation that accompanies the breakdown of radiostrontium are described.The sensitivity of these methods based on the assessments of beta spectra both after radiochemical procedures and without radiochemistry is presented.The objective of this paper is to review the spectroscopic procedures that have been developed and used to determine radiostrontium in various matrices; they are focused on modern methods.Samples of fuel particles of different origins, obtained from the Chernobyl Nuclear Power Plant Unit 4, were analyzed using the methods presented in this study.

Keywords: accidents, nuclear; accidents, power reactor; Chernobyl; detector, radiation

Health Phys.120(4):378-386; 2021

IntakeRatioof131Ito137CsDerivedfromThyroidandWhole-bodyDosestoResidentsofIwakiCityinJapan'sFukushimaPrefecture

Eunjoo Kim1, Kazuaki Yajima1, Yu Igarashi1,2, Kotaro Tani1, Shozo Hashimoto1, Takashi Nakano1, Makoto Akashi1,3, Osamu Kurihara1

(1.National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba-city, Chiba 263-8555, Japan;2.The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-city, Chiba 277-0882, Japan;3.Ryugasaki Public Health Center, 2983-1 Ryugasaki-shi, Ibaraki 301-0822, Japan)

Abstract:It is very important to determine the precise internal thyroid doses of Fukushima residents involved in the 2011 Fukushima nuclear disaster, particularly for small children.This has been challenging due to the lack of direct human measurements to identify131I, the biggest contributor to the thyroid doses.We previously used a dataset of late whole-body counter(WBC)measurements targeting134Cs and137Cs for the thyroid dose estimation in comparison with the intake ratios of131I to137Cs(or134Cs)derived from thyroid and whole-body doses individually obtained from different subject groups, assuming simultaneous acute intake via inhalation.Herein, we applied the same method to the doses of residents in Iwaki city(located south of the Fukushima Daiichi Nuclear Power Plant)with a relatively high activity ratio(131I/137Cs)for the ground deposition density.Our analyses revealed that the intake ratio(131I/137Cs)for the Iwaki residents was 4.2-4.3, which is relatively consistent with the values obtained in other studies(average 3.0-5.0).No regional difference in the intake ratios from other areas was observed, but further studies are required to determine the accurate intake ratio in the early phase of the accident, in particular focusing on the reasonable interpretation of results of the late WBC measurements to evaluate the actual Cs intake.

Keywords: accidents, nuclear; dose assessment; Fukushima Daiichi; intake, radionuclide

Health Phys.120(4):387-399; 2021

SoftwareToolsfortheEvaluationofClinicalSignsandSymptomsintheMedicalManagementofAcuteRadiationSyndrome—AFive-yearExperience

Matthias Port1, Julian Haupt1, Patrick Ostheim1, Matthäus Majewski1,2, Stephanie E.Combs3,4,5, Mike Atkinson6, Michael Abend1

(1.Bundeswehr Institute of Radiobiology affiliated to the University Ulm, Neuherbergstraße 11, 80937, Munich, Germany;2.Department of Urology, Bundeswehrkrankenhaus Ulm, 89081 Ulm, Germany;3.Department of Radiation Oncology, Technical University of Munich(TUM), Ismaninger Straße 22, 81675 Munich, Germany;4.Institute of Radiation Medicine(IRM), Department of Radiation Sciences(DRS), Helmholtz Zentrum München(HMGU), Oberschleißheim, Germany;5.Deutsches Konsortium für Translationale Krebsforschung(DKTK), Partner Site Munich, Germany;6.Department of Radiation Sciences(DRS), Institute of Radiation Biology, Helmholtz Zentrum München, Oberschleißheim, Germany)

Abstract:A suite of software tools has been developed for dose estimation(BAT, WinFRAT)and prediction of acute health effects(WinFRAT, H-Module)using clinical symptoms and/or changes in blood cell counts.We constructed a database of 191 ARS cases using the METREPOL(n= 167)and the SEARCH-database(n= 24).The cases ranged from unexposed(RC0), to mild(RC1), moderate(RC2), severe(RC3), and lethal ARS(RC4).From 2015-2019, radiobiology students and participants of two NATO meetings predicted clinical outcomes(RC, H-ARS, and hospitalization)based on clinical symptoms.We evaluated the prediction outcomes using the same input datasets with a total of 32 teams and 94 participants.We found that:(1)unexposed(RC0)and mildly exposed individuals(RC1)could not be discriminated;(2)the severity of RC2 and RC3 were systematically overestimated, but almost all lethal cases(RC4)were correctly predicted;(3)introducing a prior education component for non-physicians significantly increased the correct predictions of RC, ARS, and hospitalization by around 10%(p<0.005)with a threefold reduction in variance and a halving of the evaluation time per case;(4)correct outcome prediction was independent of the software tools used; and(5)comparing the dose estimates generated by the teams with H-ARS severity reflected known limitations of dose alone as a surrogate for H-ARS severity.We found inexperienced personnel can use software tools to make accurate diagnostic and treatment recommendations with up to 98% accuracy.Educational training improved the quality of decision making and enabled participants lacking a medical background to perform comparably to experts.

Keywords: education; exposure, radiation; health effects; radiobiology

Health Phys.120(4):400-409; 2021

TheNeutrophiltoLymphocyteRatioasaTriageToolinCriticalityAccidents

Ronald E.Goans1,2, Carol J.Iddins2

(1.MJW Corporation, Amherst, NY;2.Radiation Emergency Assistance Center/Training Site, Oak Ridge, TN)

Abstract:During triage of possibly irradiated individuals after a criticality accident or nuclear weapon event, it is necessary to decide whether a patient has experienced a clinically significant dose(> 2 Gy)that would require referral for additional evaluation and medical treatment.This is a binary decision: yes or no.The neutrophil-to-lymphocyte ratio(NLR)is an appropriate decision parameter, is simple to obtain in field operations, and is recognized in clinical medicine as an independent marker of systemic inflammation.NLR is evaluated for usefulness in triage using data from the Radiation Accident Registry at the Radiation Emergency Assistance Center/Training Site(REAC/TS).A criticality accident data set has been prepared using historic complete blood counts from 12 criticality events with 33 patients.In addition, a cohort of 125 normal controls has been assembled for comparison with the radiation accident data.In the control set, NLR is found to be 2.1 ± 0.06(mean ± SEM)and distributed consistent with a Gaussian distribution.A patient from the 1958 Y-12 criticality accident is presented as an example of the time dependence of NLR after an event.In this case, NLR is statistically elevated above controls from <4 h until ～20 d post-event, and for times >20 d post-event, NLR is less than the control value, returning to baseline > ～40 d.The latter result has been confirmed using late hematological data taken from patients at Hiroshima and Nagasaki, and this appears to be a general finding.Since triage is a binary decision, analyzing NLR with receiver operating characteristic(ROC)statistics is appropriate.Maximizing the Youden J statistic(sensitivity + specificity-1)determines an appropriate decision point.For this data set, the decision point for NLR is found to be 3.33, with area under the curve(AUC)0.865, sensitivity 0.67, specificity 0.97, positive predictive value(PPV)0.85, and negative predictive value(NPV)0.92.Therefore, when a known criticality accident or nuclear weapon event has occurred and if the patient’s NLR is greater than 3.33 early post-event, then that person should be referred for further health physics and medical evaluation.

Keywords: accident analysis; accidents, nuclear; biokinetics; kinetics

Health Phys.120(4):410-416; 2021

ReconstructionofEnrichedUraniumReleasedtoAirfromtheFormerApolloFacility,Apollo,Pennsylvania

Emily A.Caffrey1, Paul G.Voillequé2, Arthur S.Rood3, Helen A.Grogan4, H.Justin Mohler5, Kathleen R.Meyer6, John E.Till7

(1.Radian Scientific, LLC, 806 Wells Ave SE, Huntsville, AL 35801;2.MJP Risk Assessment, Inc., 7085 East Bayaud Avenue, Denver, CO 80230;3.K-Spar, Inc., 4835 W Foxtrail Lane, Idaho Falls, ID 83402;4.Cascade Scientific, Inc., 1678 NW Albany Avenue, Bend, OR 97703;5.Bridger Scientific, Inc., 125 Jackpot Lane, Belgrade, MT 59714;6.Keystone Scientific, Inc., 5009 Alder Court, Fort Collins, CO 80525;7.Risk Assessment Corporation, 417 Till Road, Neeses, SC 29107)

Abstract:The former Apollo facility converted enriched uranium hexafluoride into uranium oxide for shipment to nuclear fuel fabrication plants from 1957 to 1983.This paper describes quantification of the source term from the Apollo facility in terms of quantities of uranium released, particle size, and solubility characteristics.Releases occurred through stacks, rooftop vents, and an incinerator that operated from 1964 to 1969.Incidental and accidental releases are addressed as part of this analysis.Atmospheric releases of uranium from plant operations were estimated from stack sampling and production records.Roof vents, both filtered and unfiltered, were the major emission points from the plant.The total estimated release of uranium activity(including234U,235U, and238U)to the air was 28 GBq.Measurements by others found that the releases were primarily associated with large particles and that their solubility was variable but generally low(Class Y).The release estimates presented here and those findings were incorporated into a sophisticated atmospheric transport model to estimate atmospheric concentrations and soil contamination levels due to the releases and to reconstruct historical doses to individuals that lived in the vicinity of the former Apollo facility.

Keywords:138U; contamination, environmental; dose assessment; radiation, atmospheric

Health Phys.120(4):417-426; 2021

TrendsofAnnualWhole-bodyOccupationalRadiationExposureforIndustrialPracticesinChina(2009-2018)

Shengnan Fan1, Jun Deng1, Baojun Qiao2, Wenshan Zhou3, Tuo Wang1, Wen Guo1, Quanfu Sun1

(1.Key Laboratory of Radiological Protection and Nuclear Emergency, China CDC & National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing 100088, China;2.Liaoning Provincial Center for Disease Control and Prevention, Shenyang 110000, China;3.Hubei Provincial Center for Disease Control and Prevention, Wuhan, 430079, China)

Abstract:The national status and dose trends on the occupational exposure to ionizing radiation in industrial practices for 2009-2018 in China are presented in terms of seven occupational categories.A total of 504,538 industrial radiation workers were monitored for the period 2009-2018, with a continuous increase in the number of workers from 23,789 in 2009 to 66,017 in 2018.The annual average effective doses were 0.399, 0.425, 0.392, 0.376, 0.346, 0.355, 0.312, 0.305, 0.270, and 0.230 mSv from 2009 to 2018, respectively, which were well lower than the recommended occupational dose limit of 20 mSv y-1for radiation workers.The Mann-Kendall test result shows a statistically significant decreasing trend at a rate of 0.02 mSv y-1in average annual effective doses(p<0.001).In addition, more than 95.4% of radiation workers in industrial practices received an average annual effective dose less than the public dose limit of 1 mSv.It was also found that the average annual effective doses in industrial radiography and well logging were significantly higher than those in five other categories(p<0.001).Based on these observations, it is still necessary to control and manage the workplace and radiation workers to control occupational exposure as low as reasonably achievable, especially for the workers engaged in these two activities.

Keywords: exposure, occupational; dose assessment; dose equivalent; effective dose

Health Phys.120(4):427-432; 2021

StudyofRadiologicalAssessmentModelsforContaminatedSoil,Buildings,andOutdoorSurfaces:Overview,Comparison,SimilaritywithChemicalModels,Challenges,andLessonsLearned

Nasser A.Shubayr1,2,3

(1.Diagnostic Radiology Department, College of Applied Medical Sciences, Jazan University, Al Maarefah Rd, POB 114, Jazan, Saudi Arabia 45142;2.Medical Research Center, Jazan University, Jazan, Saudi Arabia;3.Radiation Protection Unit, Jazan University, Jazan, Saudi Arabia)

Abstract:A research project was conducted by the United States Environmental Protection Agency’s(EPA)Superfund remedial program to study radiological assessment models used for contaminated sites.Several models developed by regulatory agencies in different countries are studied to present overview and comparisons.These models are recommended by governmental agencies for radiological assessment of contaminated soil, inside buildings, and outdoor surfaces.The project also addressed the methodological consistency between the EPA and the United Kingdom Environment Agency(UK EA)for radiological and chemical assessment models.The main purpose of this project is to establish a common ground for cooperation between regulatory agencies by facilitating better understanding of each agency’s modeling approach and identifying the similarities and differences between these agencies.The project produced five reports that are published at the EPA’s website.This paper summarizes the content of each report and presents results of a survey distributed electronically following an EPA webinar about the research projects, including the familiarity of the respondents with these models.All findings were statistically analyzed.

Keywords: review paper; contamination, environmental; environmental impact; modeling, environmental

Health Phys.120(4):433-441; 2021

TechnicalDetailsoftheSigmaFactorAlarmMethodwithinAlphaCAMs

Alan Justus1

(1.Los Alamos National Laboratory, MS J573, Los Alamos, NM 87545)

Abstract:Some test must be applied to the low-level count data from alpha continuous air monitors(CAMs)to determine if the count is statistically significant(i.e., significantly above background).The method should be as sensitive as possible, automatically desensitizing when required due to radon progeny, yet in such a manner as to not exceed an acceptable false-alarm rate.The test that has been historically used within many alpha CAMs to accomplish these goals is the so-called sigma factor approach.In this paper, this approach is discussed with respect to four common CAM algorithms.These algorithms are referred to as the theoretical best possible algorithm, the 4-ROI algorithm, the tail-fitting algorithm, and the peak-fitting algorithm.Relative sensitivities are estimated for each algorithm.

Keywords: instruments; monitoring, air; plutonium; radioactivity, airborne

Health Phys.120(4):442-453; 2021

PreliminaryExperienceswiththeRexonUL-320-FDR:AnAutomatedThermoluminescentDosimeterReaderwithRemovableContactHeatingPlanchetsandanInfraredTemperatureFeedbackSystem

John R.Kuchta, Jack H.Thiesen, Jordan D.Noey, Long Kiu Chung, Kimberlee J.Kearfott1

(1.Department of Nuclear Engineering and Radiological Sciences, College of Engineering, The University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109-2104)

Abstract:The Rexon UL-320 FDR is a novel resistive-heating thermoluminescent dosimeter reader with a unique temperature measurement system and an automated dosimeter processing mechanism.The removable contact heating planchets have black-body adhesives on the back for capturing temperature information with infrared sensors.A heating cycle feedback loop ensures accurate, precise, and reproducible heating sequences.Heating rates between 0.8 and 40 ℃ s-1for up to 1,000 s are possible.Photomultiplier tube sensitivity and drift, dark current counts, and planchet glow were measured experimentally.Additionally, 25 LiF:Mg,Ti dosimeters were calibrated to demonstrate reader performance.Sensitivity was optimized at 1,200 V, which produced the highest reference light count to dark current count ratio while extending photomultiplier tube life.Dark current counts measured with typical time-temperature profiles for LiF:Mg,Ti were below 10 counts per channel but increased by up to 2.5% for more extreme heating cycles.Reader sensitivity drifts of up to 10% were observed during extended automated operations with typical time-temperature profiles.Total counts resulting from planchet glow decreased with faster heating rates.Calibrations performed with LiF:Mg,Ti dosimeters yielded results comparable to more established reader designs.Spikes were observed in ～3% of the glow curves from planchet dust and oil burning off at elevated temperatures.The use of N2gas and sensitivity drift corrections are recommended to improve dosimetry performance for the UL-320 FDR reader.

Keywords: operational topics; dosimetry; dosimetry, thermoluminescent; instrumentation

Health Phys.120(4):463-471; 2021

RelationshipBetweenTerrestrialBackgroundandRemedialCriteriaforNaturallyOccurringRadioactiveMaterialintheUnitedStates

Steven H.Brown1

(1.SHB Inc., 7505 S.Xanthia Place, Centennial, CO 80112)

Abstract:In the United States(US), Federal and State agencies have established radiological public exposure limits and remedial action(“clean up”)criteria for naturally occurring radionuclides(NORM—primarily for uranium and thorium series radionuclides).Often, these criteria are intended to control human exposure to what is referred to in the US as technologically enhanced naturally occurring radioactive material(TENORM).This can be any naturally occurring radioactive material for which the potential for human exposure has been enhanced due to anthropogenic(human activities), e.g., removal from its “place in nature,” and/or processed in some way resulting in concentration.In some cases, the values of these regulatory criteria can be similar to or even less than those levels of exposure and those concentrations of NORM that exists in nature independent of any previous human activity.The potential variability of NORM radionuclides in the soil and rocks can be significant, even over relatively short distances or depths due to factors such as geology, hydrology, and geochemistry.Given this, it is important to recognize that defining “the radiation background” for purposes of establishing and/or comparing remedial action criteria and/or exposure limits requires recognition of the specificity at the location(s)of interest, not in other geological and/or mineralogical regimes several miles away.The purpose of this paper is to demonstrate this variability for comparison to exposure levels and concentrations being defined in the US as levels above which require regulatory control and/or above which are being defined as an “unacceptable risk”.The primary background exposure component of specific interest here is the annual dose contribution from terrestrial radiation exposure, i.e., from uranium and thorium series radionuclides in the ground, excluding radon inhalation.The exposure sources being controlled by some US regulatory limits are primarily associated with the primordial radionuclides in soil.The average annual terrestrial component of background can vary by upwards of a few tenths of a mSv across the US that can be several times higher than the applicable exposure limits.This can result in “unacceptable risk” or “remedial action” concentration criteria statistically equivalent to or less than the background concentrations of these same primordial nuclides.The statistical and analytical uncertainties of distinguishing naturally occurring radionuclides(i.e., NORM)from those resulting from anthropogenic(human caused)activities(i.e., TENORM)can be quite challenging and in some cases may be technically impossible.Consideration must be given to the relationship of the amount of actual total risk avoidance achieved if any, relative to the traditional health and safety risks of construction and associated construction and waste management costs for remedial activities, so that a practical and scientifically based approach for development of these criteria can be achieved.

Keywords: operational topics; radiation, background; regulations; uranium mines

Health Phys.120(4):472-482; 2021