Health Phys. Abstracts，Volume 120,Number 6

ExternalDosetoRecoveryTeamsFollowingaWide-areaNuclearorRadiologicalReleaseEvent

Michael D. Kaminski1, Keith Sanders2, Katherine Hepler1, Matthew Magnuson3, Jeremy Slagley2

(1.Strategic Security Sciences Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, IL 60439;

2.Air Force Institute of Technology, Department of Systems Engineering and Management, 2950 Hobson Way, Wright-Patterson Air Force Base, OH 45433;

3.US Environmental Protection Agency, Office of Research and Development, Center for Environmental Solutions and Emergency Response, Homeland Security & Materials and Management Division, 26 W. Martin Luther King Drive, Cincinnati, OH 45268)

Abstract:The common radionuclide137Cs is a gamma-ray source term for nuclear reactor accidents, nuclear detonations, and potential radionuclide dispersal devices. For wide-area contamination events, one remediation option integrates water washing activities with on-site treatment of water for its immediate reuse. This remediation option includes washing building and roadways via firehose, collecting the wash water, and passing the contaminated water through chemical filtration beds. The primary objective of this study was to quantify the dose incurred to workers performing a remediation recovery effort for roadways and buildings following a wide-area release event. MicroShield® was employed to calculate the dose to workers at the roadway level and to calculate total dose rates while performing washing activities. This study finds that for a realistic contamination scenario for a wide area of a large urban environment, decontamination crews would be subjected to <220 μSv per person, much less than the 50,000 μSv limit for occupational dose. By extrapolation, one decontamination team of 48 people could continue washing operations on a total of 2.8 km-2before reaching their incurred annual dose limits. Though it is unrealistic to assign one team that entire area, we can conclude external dose will not limit worker deployment given the range of contamination levels adopted in this study.

Keywords:137Cs; accidents, nuclear; dose, external; occupational safety

Health Phys. 120(6):591-599; 2021

DTPATreatmentofWoundContaminationinRatswithAmericium:EvaluationofUrinaryProfilesUsingSTATBIODISShowsImportanceofPromptAdministration

Stephanie Lamart1,2, Anne Van der Meeren1, Sylvie Coudert1, Nicolas Baglan1, Nina M. Griffiths1

(1.Laboratoire de Radio Toxicologie, CEA, Université Paris-Saclay, 91297 Arpajon, France;

2.Laboratoire d’Évaluation de la Dose Interne, Institut de Radioprotection et de Sreté Nucléaire, IRSN/PSE-SANTE/SDOS/LEDI, 31 avenue de la Division Leclerc, 92260 Fontenay-aux-Roses, France)

Abstract:In the nuclear industry, wound contamination with americium is expected to increase with decommissioning and waste management. Treatment of workers with diethylenetriaminepentaacetic acid (DTPA) requires optimization to reduce internal contamination and radiation exposure. This work aimed at evaluating and comparing different DTPA protocol efficacies after wound contamination of rats with americium. Wound contamination was simulated in rats by depositing americium nitrate in an incision in the hind limb. Different routes, times, and frequencies of DTPA administration were evaluated. Individual daily urinary americium excretion and tissue retention were analyzed using the statistical tool STATBIODIS. Urinary profiles, urinary enhancement factors, and inhibition percentages of tissue retention were calculated. A single DTPA administration the day of contamination induced a rapid increase in americium urinary excretion that decreased exponentially over 7 d, indicating that the first DTPA administration should be delivered as early as possible. DTPA treatment limited americium uptake in systemic tissues irrespective of the protocol. Liver and skeleton burdens were markedly reduced, which would drive reduction of radiation dose. Local or intravenous injections were equally effective. Inherent difficulties in wound site activity measurements did not allow identification of a significant decorporating effect at the wound site. Repeated intravenous injections of DTPA also increased americium urinary excretion, which supports the use of multiple DTPA administrations shortly after wound contamination. Results from these statistical analyses will contribute to a better understanding of americium behavior in the presence or absence of DTPA and may aid optimization of treatment for workers.

Keywords:241Am; analysis, statistical; DTPA; dose assessment

Health Phys. 120(6):600-617; 2021

ContaminationMeasurementsfromSimultaneousActivatedPotassiumBromideRadiologicalDispersalDeviceswithaCollimatedVehicularSensor

Nathanael Simerl1, Jace Beavers1, Jacob Milburn1, Miranda Dodson1, Ryan Strahler1, Richard Kroeger2, Ivan Ulloa-Garcia2, Bryan Moosman2, Terence Sin2, Jeffrey Kagan2, Kyle Nelson2, Nathan Paradis2, Amir Alexander Bahadori1, Walter McNeil1

(1.Alan Levin Department of Mechanical and Nuclear Engineering, Kansas State University, 3002 Rathbone Hall, 1701B Platt Street, Manhattan, KS 66506;

2. Naval Information Warfare Systems Command, 4301 Pacific Highway, San Diego, CA 92110-3127)

Abstract:Surface contamination was quantified over a distributed source of activated potassium bromide from three detonations of Radiological Dispersal Devices (RDDs) at the Idaho National Laboratory Radiological Response Training Range, with a maximum sampled area of 19,900 m2, to provide a baseline comparison with other rapid, remote mapping methods. Measurements were obtained with a cerium bromide sensor collimated to a field of view of 3.14 m2, using lead shielding, and towed behind a ground vehicle. Sensor response correction factors for activated potassium bromide were calculated through simulation with SWORD to obtain activity per meter-squared. Continuous maps were produced by interpolating coverage from lawnmower raster scans. Radiological data was overlaid with aerial imagery from an automated unmanned aerial vehicle flight to provide contextual geological information relative to contamination levels. The contamination distribution measurements will be compared to unmanned aerial vehicle methods in future work.

Keywords: detector, radiation; monitoring, environmental; surface contamination; surveys

Health Phys. 120(6):618-627; 2021

ExposuretoRadonandProgenyinaTouristCavern

Jeri L. Anderson, Leonard M. Zwack, Scott E. Brueck1

(1.Division of Field Studies and Engineering, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, OH 45226)

Abstract:The primary objective of this work was to characterize employee exposure to radon and progeny while performing guide/interpretation and concessions duties in a tourist cavern. Radon gas and progeny concentrations, fraction of unattached progeny, and other environmental parameters were evaluated in a popular tourist cavern in Southeastern New Mexico. Alpha-track detectors were used to measure radon gas in several cavern locations during a 9 mo period. Additionally, radon gas and attached and unattached fractions of radon progeny were measured at three primary cavern work locations during a 1 d period using a SARAD EQF 3220. Radon gas concentrations in the cavern were elevated due to extremely low air exchange rates with substantial seasonal variation. Mean measured radon concentrations ranged from 970 to 2,600 Bq m-3in the main cavern and from 5,400 to 6,000 Bq m-3in a smaller cave associated with the regional cave system. Measurements of unattached fractions (0.40-0.60) were higher than those commonly found in mines and other workplaces, leading to the potential for relatively high worker dose. Although radon gas concentrations were below the Occupational Safety and Health Administration Permissible Exposure Limit, employees working in the cavern have the potential to accrue ionizing radiation dose in excess of the annual effective dose limit recommended by the National Council on Radiation Protection and Measurements due to a high unattached fraction of radon progeny. There was a strong negative correlation between unattached fractions and equilibrium factors, but these parameters should be further evaluated for seasonal variation. Introduction of engineering controls such as ventilation could damage the cavern environment, so administrative controls, such as time management, are preferred to reduce employee dose.

Keywords: exposure, occupational; radon; radon progeny; safety standards

EvaluationofRadiationProtectionMethodsforAssistantStaffduringCTImaginginHigh-energyTrauma:LensDosimetrywithaPhantomStudy

Joji Ota1,2, Hajime Yokota3, Tatsuya Kawasaki1, Junichi Taoka1, Hideyuki Kato1, Koichi Chida2, Yoshitada Masuda1, Takashi Uno3

(1.Department of Radiology, Chiba University Hospital, 1-8-1, Inohana, Chuo-ku, Chiba City, Chiba 260-8677, Japan;

2. School of Radiological Technology, Health Sciences, Graduate School of Medicine, Tohoku University, 2-1 Seiryo, Aoba, Sendai, Miyagi, Japan;

3. Diagnostic Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba City, Chiba 260-8670, Japan)

Abstract:Staff are exposed to radiation in the scanning room when assisting with CT scans of patients requiring ventilatory support during procedures. We measured lens doses using a phantom during a high-energy trauma protocol. Dosimetry showed that the unprotected lens received 2.02 mGy on the right and 1.91 mGy on the left, which are not negligible doses. Respective exposures to the right and left lens were 53.6% and 55.1% when wearing 0.07 mm Pb protective glasses with side covers; 53.7% and 64.2% when wearing 0.7 mm Pb glasses without side covers when facing away from the patient couch; and 92.1% and 91.2% using protective shielding in the gantry. Since the face direction may change during assistance with CT imaging, it is desirable that the protective glasses have a shape with a side cover. The protective shielding had a major radiation reduction effect, although it is expensive to acquire, install, and maintain.

Keywords: computed tomography; exposure; occupational; radiation dose; radiation protection

Health Phys. 120(6):635-640; 2021

AreX-raySafetyGlassesAloneEnoughforAdequateOcularProtectioninComplexRadiologicalInterventions?

Mathias Grau1,2, Osama Eldergash1, Sandeep Sunder Amin1, Tobias Kowald1, Johannes Schnabel1, Anika Wißmann3, Sebastian Simka3, Ajay Chavan4, Christian Mathys5,6, Björn Poppe7, Bernhard Schmuck8, Rohit Philip Thomas9

(1.Institute of Diagnostic and Interventional Radiology, Klinikum Oldenburg AöR, Carl von Ossietzky University Oldenburg, Oldenburg;

2. School for Medical Technical Radiology Assistants, Klinikum Oldenburg AöR, Carl von Ossietzky University Oldenburg, Oldenburg;

3. Institute of Diagnostic and Interventional Radiology, Ammerland Klinik GmbH, Westerstede;

4. Institute of Diagnostic and Interventional Radiology, Christliches Krankenhaus Quakenbrück, Quakenbrück;

5. Institute of Radiology und Neuroradiology, Evangalisches Krankenhaus Oldenburg, Carl von Ossietzky University Oldenburg, Oldenburg;

6. Research Center Neurosensory Science, Carl von Ossietzky University Oldenburg, Oldenburg;

7. Department of Medical Radiation Physics, Pius-Hospital, Carl von Ossietzky University Oldenburg, Oldenburg;

8. Division of Radiology, Clinic for Vascular Medicine, Vascular Centre, Rotes Kreuz Krankenhaus, Bremen;

9. Department of Diagnostic and Interventional Radiology, University Hospital Marburg, Philipps University, Marburg)

Abstract:The maximum annual radiation ocular dose limit for medical staff has been reduced to 20 mSv in the current European directive 2013/59/Euratom. This multi-centric study aims at reporting the protected and unprotected eye lens doses in different fluoroscopically guided interventions and to evaluate any other factors that could influence the ocular dose. From July 2018 to July 2019, ocular radiation doses of six interventionists of four departments during complex interventions were recorded with a thermoluminescent dosimeter in front of and behind radiation protection glasses to measure the protected and unprotected doses. The position of personnel, intervention type, fluoroscopy time, total body dose and use of pre-installed protection devices like lead acrylic shields were also systematically recorded. Linear regression analysis was used to estimate the doses at 2 y and 5 y. The annual unprotected/protected ocular doses of six interventionists were 67/21, 32.7/3.3, 27.4/5.1, 7/0, 21.8/2.2, and 0/0 mSv, respectively. The unprotected dose crossed the 20 mSv annual limits for four interventionists and protected dose for one less experienced interventionist. The estimated 5 y protected ocular dose of this interventionist was 101.318 mSv (95%CI96.066-106.57), also crossing the 5 y limit. The use of a lead acrylic shield was observed to have a significant effect in reducing ocular doses. The annual unprotected and protected ocular doses for interventionists dealing with complex interventions could cross the present permitted yearly limit. The measurement of significant protected ocular dose behind the radiation protection glasses emphasizes the additional indispensable role of pre-installed radiation protection devices and training in reducing radiation doses for complex procedures.

Keywords: dose, organ; exposure, radiation; occupational safety; X-ray imaging

Health Phys. 120(6):641-647; 2021

SimulationsandExperimentalVerificationsofanAlgorithmforRadiationSourceMappingandNavigationalPathGeneration

Long Kiu Chung, Andrew J. E. Kent, Margaret A. Cooney, Jordan D. Noey, Kyle J. Liebler, Kimberlee J. Kearfott1

(1.Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI 48104)

Abstract:Accurate and efficient mapping and localization of both ionizing and non-ionizing radiation sources are important across many different fields. As such, a versatile mapping and navigational path generation algorithm, which can be applied to any point source measurements that follow an inverse-square characteristic, was developed using non-linear least squares methods. Forty thousand simulations were performed on the algorithm, which located sources successfully in a 10 m × 10 m × 10 m three-dimensional space with a success rate of over 80% across different noise functions, given a proportional constant of 10 to 1,000. The algorithm was also verified experimentally with small-scale radioactive decontamination of a 70 cm × 70 cm surface and localization of a lost Wi-Fi router in a 70 m × 70 m open field. One hundred twenty-one measurements were taken from each experiment, which were then fed into the algorithm for navigation. For the radioactive137Cs source, the estimated locations were within 7 cm × 7 cm of the answer in 79.3% of the scenarios, while the Wi-Fi router was located to within 7 m × 7 m in 57.9% of the tests. In general, the method requires much less information and data than a geographically comprehensive survey and thus shows a lot of potential for practical applications, such as lost source retrieval with unmanned aerial vehicles, small-scale decontamination, mapping undocumented Wi-Fi routers or radio towers, and radiation simulation with radio signals. Different failure modes, desirable features, and potential improvements were also identified but remain as future work.

Keywords: algorithm; detector, radiation; sampling; statistics

Health Phys. 120(6):648-660; 2021

InhalationofSolublePlutonium:53-yearFollow-upofManhattanProjectWorker

(1.United States Transuranium and Uranium Registries, Washington State University, 1845 Terminal Drive, Suite 201, Richland, WA 99354-4959)

Abstract:This whole-body tissue donor to the United States Transuranium and Uranium Registries was occupationally exposed to plutonium nitrate-dioxide mixture via chronic inhalation. This individual was involved in the Manhattan Project operations and later participated in medical follow-up studies. Soft tissues and bones collected at autopsy were analyzed for238Pu,239+240Pu, and241Am. Fifty-three years post-intake, 700±2 Bq of239+240Pu were still retained in the skeleton, 661±11 Bq in the liver, and 282±3 Bq in the respiratory tract. Bioassay measurements and organ activities at the time of death were used to estimate the intake and radiation doses using the TAURUS internal dosimetry software. For this individual, an ICRP Publication 130 Human Respiratory Tract Model with case-specific particle size of 0.3 μm, ICRP Publication 100 Human Alimentary Tract Model, and ICRP Publication 141 Plutonium Systemic Model adequately described long-term plutonium retention and excretion. The total cumulative239+240Pu intake of 31,716 Bq was estimated, of which 24,853 Bq (78.4%) were contributed by inhalation of plutonium nitrate and 6,863 Bq (21.6%) of plutonium dioxide. The committed equivalent doses to the red bone marrow, bone surface, liver, lungs, and brain were 0.71 Sv, 6.5 Sv, 8.3 Sv, 3.8 Sv, and 0.068 Sv, respectively. The committed effective dose was 1.22 Sv.

Keywords: biokinetics; human organs; inhalation; plutonium

Health Phys. 120(6):661-670; 2021

SurveillanceofDepletedUranium-exposedGulfWarVeterans:MoreEvidenceforBoneEffects

Melissa A. McDiarmid1,2, Joanna M. Gaitens1,2, Stella Hines1,2, Marianne Cloeren1,2, Richard Breyer1, Marian Condon1, Marc Oliver1,2, Tracy Roth1,2, Patricia Gucer1,2, Bruce Kaup1, Lawrence Brown1,3, Clayton H. Brown4, Moira Dux1, Danielle Glick2, Michael R. Lewin-Smith5, Frederick Strathmann5, Hanna Xu5, Maria A. Velez-Quinones5, Elizabeth Streeten2

(1.Department of Veterans Affairs Medical Center Baltimore, MD;

2. Department of Medicine, University of Maryland School of Medicine, Baltimore, MD;

3. Department of Pathology, University of Maryland School of Medicine, Baltimore, MD;

4. Biophysical Toxicology, The Joint Pathology Center, Silver Spring, MD;

5. Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, 655 W Baltimore S, Baltimore, MD 21201)

Abstract:Gulf War I veterans who were victims of depleted uranium (DU) “friendly-fire” incidents have undergone longitudinal health surveillance since 1994. During the spring of 2019, 36 members of the cohort were evaluated with a monitoring protocol including exposure assessment for total and isotopic uranium concentrations in urine and a comprehensive review of health outcomes, including measures of bone metabolism and bone mineral density (BMD) determination. Elevated urine U concentrations were observed in cohort members with retained depleted uranium (DU) shrapnel fragments. In addition, a measure of bone resorption, N-telopeptide, showed a statistically significant increase in those in the high DU subgroup, a finding consistent with a statistically significant decrease in bone mass also observed in this high DU subgroup compared to the low DU subgroup. After more than 25 y since first exposure to DU, an aging cohort of military veterans continues to show few U related health effects in known target organs of U toxicity. The new finding of impaired BMD in the high DU subgroup has now been detected in two consecutive surveillance visits. While this is a biologically plausible uranium effect, it is not reflected in other measures of bone metabolism in the full cohort, which have largely been within normal limits. However, ongoing accrual of the U burden from fragment absorption over time and the effect of aging further impairing BMD suggest the need for future surveillance assessments of this cohort.

Keywords: exposure, occupational; health effects; occupational safety; toxicology

Health Phys. 120(6):671-682; 2021

RadiationandtheSkepticalPublic:TipsandToolsforCommunicatingEffectively

Emily Caffrey1

(1.Radian Scientific, LSS, Huntsville AL 35801)

Abstract:Public communication about radiation is tricky business. Members of the public are frequently skeptical about messages from scientific sources, particularly when it comes to radiation. As radiation protection professionals, it is our job to relay scientifically sound information in a simple, clear, and concise manner. This paper discusses the Health Physics Society’s “Ask The Experts” feature, the society’s most successful public education endeavor with over one million visitors annually. The keys to effective communication of technical information are demonstrating empathy and compassion, keeping the language simple and concise, and offering sources of additional information to empower the individual to learn more on their own. The two most common categories of questions—radiation exposures from diagnostic imaging procedures and radiation exposures to the fetus—are discussed in detail, and some general information on how to respond to these types of questions is provided. A template for responding to public questions is provided, along with some examples.

Keywords: operational topics; education, health physics; public information; risk communication

Health Phys. 120(6):693-698; 2021