Health Phys. Abstracts，Volume 119,Number 6

DoseAssessmentFollowinga238Pu-contaminatedWoundCasewithChelationandExcision

Deepesh Poudel, John A. Klumpp, Luiz Bertelli, Sara Dumit, Tom L. Waters

Abstract:The urinary excretion and wound retention data collected after a238Pu-contaminated wound were analyzed using Markov Chain Monte Carlo (MCMC) to obtain the posterior distribution of the intakes and doses. An empirical approach was used to model the effects of medical treatments (chelation and excision) on the reduction of doses. It was calculated that DTPA enhanced the urinary excretion, on average, by a factor of 17. The empirical analysis also allowed calculation of the efficacies of the medical treatments—excision and chelation averted approximately 76% and 5.5%, respectively, of the doses that would have been if there were no medical treatment. All bioassay data are provided in the appendix for independent analysis and to facilitate the compartmental modeling approaches being developed by the health physics community.

Keywords:238Pu; bioassay; dosimetry, internal; modeling, dose assessment

Health Phys. 119(6):690-703; 2020

ResponsetoaSkinPunctureContaminatedwith238PuatLosAlamosNationalLaboratory

John Klumpp, Luiz Bertelli, Sara Dumit, Milan Gadd, Deepesh Poudel, Tom L. Waters1

(1. Los Alamos National Laboratory, Radiation Protection Division, MS G761, Los Alamos, NM 87545)

Abstract:The three principal pathways for intakes of plutonium are ingestion, inhalation, and contaminated wounds. In August 2018, a glovebox worker at Los Alamos National Laboratory (LANL) sustained a puncture from a thread of a braided steel cable contaminated with238Pu. The puncture produced no pain, no blood, and little or no visible mark. As a result, the potential for a contaminated wound was not immediately recognized, and a wound count was not conducted until elevated urine bioassay results were received 12 d after the incident. This paper discusses the circumstances of the incident, along with the medical response and dose assessment, and a discussion of the risks and benefits of the medical interventions.

Keywords: accidents, nuclear; alpha particles; bioassay; wound

Health Phys. 119(6):704-714; 2020

DevelopmentofaNewChelationModel:BioassayDataInterpretationandDoseAssessmentafterPlutoniumIntakeViaWoundandTreatmentwithDTPA

Sara Dumit1, Guthrie Miller2, John A. Klumpp1, Deepesh Poudel1, Luiz Bertelli1, Tom L. Waters1

(1.Los Alamos National Laboratory Los Alamos, NM;2. Los Alamos National Laboratory, Radiation Protection Division, MS G761, Los Alamos, NM 87545)

Abstract:The administration of chelation therapy to treat significant intakes of actinides, such as plutonium, affects the actinide’s normal biokinetics. In particular, it enhances the actinide’s rate of excretion, such that the standard biokinetic models cannot be applied directly to the chelation-affected bioassay data in order to estimate the intake and assess the radiation dose. The present study proposes a new chelation model that can be applied to the chelation-affected bioassay data after plutonium intake via wound and treatment with DTPA. In the proposed model, chelation is assumed to occur in the blood, liver, and parts of the skeleton. Ten datasets, consisting of measurements of14C-DTPA,238Pu, and239Pu involving humans given radiolabeled DTPA and humans occupationally exposed to plutonium via wound and treated with chelation therapy, were used for model development. The combined dataset consisted of daily and cumulative excretion (urine and feces), wound counts, measurements of excised tissue, blood, and post-mortem tissue analyses of liver and skeleton. The combined data were simultaneously fit using the chelation model linked with a plutonium systemic model, which was linked to an ad hoc wound model. The proposed chelation model was used for dose assessment of the wound cases used in this study.

Keywords: chelation; dosimetry, internal; DTPA; wound

Health Phys. 119(6):715-732; 2020

DifferenceintheCesiumBodyContentsofAffectedAreaResidentsDependingontheEvacuationTimepointFollowingthe2011FukushimaNuclearDisaster

Yu Igarashi1,2, Eunjoo Kim1, Shozo Hashimoto1, Kotaro Tani1, Kazuaki Yajima1, Takeshi Iimoto1,2, Tetsuo Ishikawa3, Makoto Akashi1,4, Osamu Kurihara1

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

Abstract:Estimating the internal thyroid dose received by residents involved in the 2011 Fukushima Daiichi Nuclear Power Plant (FDNPP) accident has been a challenging task because of the shortage of direct human measurements related to the largest contributing radioisotope to the dose,131I. In a previous dose estimation, we used the results of whole-body counter (WBC) measurements targeting134Cs and137Cs, based on the assumption that these radioisotopes were incorporated at the same time as131I in the early phase of the accident. The main purpose of this study was to clarify whether the trace of the early intake remained in the WBC measurements that were started several months after the accident. In the present work, WBC data of 1,639 persons from Namie town, one of the heavily contaminated municipalities, were analyzed together with their evacuation behavior data. The results demonstrated that the cesium detection rate in the WBC results was several times higher in the late evacuees [who evacuated outside the 20 km radius of the FDNPP at 3:00 p.m. (Japanese Local Time) on 12 March or later] compared to the prompt evacuees (who evacuated before 3:00 p.m. on 12 March). Among the adults, the cesium detection rates (and the 90th percentile values of the137Cs intake) of the prompt and late evacuees were about 20% (5.4×103Bq) and 60% (1.6×104Bq), respectively. Approximately 20% of the individuals analyzed were categorized as late evacuees. These differences in cesium would be caused by exposure to the radioactive plume in the afternoon on 12 March, which was likely to influence the late evacuees. On the other hand, the intake on 15 March, when the largest release event occurred, was expected to be relatively small for Namie town's residents. In conclusion, the trace of the early intake remained in the WBC measurements, although this would not necessarily be true for all subjects. The results obtained from this study would provide useful information for the reconstruction of the early internal thyroid doses from radioiodine in the future.

Keywords: accidents, nuclear; cesium; dose, internal; Fukushima

Health Phys. 119(6):733-745; 2020

Effectof3,3’-DiindolylmethaneonPulmonaryInjuryFollowingThoracicIrradiationinCBAMice

Evagelia C. Laiakis1,2, Elizabeth A. McCart3, Annabella Deziel1, W. Bradley Rittase3, Roxane M. Bouten3, Jyoti Jha4, W. Louis Wilkins5, Regina M. Day3, Albert J. Fornace Jr1,2

(1.Department of Oncology, Georgetown University, Washington, DC 20057;2. Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC 20057;3. Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814;4. Current address: Rise Therapeutics, Rockville, MD 20850;5. Department of Laboratory Animal Research, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA)

Abstract:The molecule 3,3’-diindolylmethane (DIM) is small, a major bioactive metabolite of indole-3 carbinol (13C), and a phytochemical compound from cruciferous vegetables released upon exposure to the gut acid environment. DIM is a proposed anti-cancer agent and was previously demonstrated to prevent radiation damage in the bone marrow and the gastrointestinal tract. Here we investigated the effect of DIM on radiation-induced injury to the lung in a murine model through untargeted metabolomics and gene expression studies of select genes. CBA mice were exposed to thoracic irradiation (17.5 Gy). Mice were treated with vehicle or DIM (250 mg kg-1, subcutaneous injection) on days-1pre-irradiation through +14 post-irradiation. DIM induced a significant improvement in survival by day 150 post-irradiation. Fibrosis-related gene expression and metabolomics were examined using lung tissue from days 15, 45, 60, 90, and 120 post-irradiation. Our qRT-PCR experiments showed that DIM treatment reduced radiation-induced late expression of collagen Iα and the cell cycle checkpoint proteins p21/waf1 (CDKN1A) and p16ink (CDKN2A). Metabolomic studies of lung tissue demonstrated a significant dampening of radiation-induced changes following DIM treatment. Metabolites associated with pro-inflammatory responses and increased oxidative stress, such as fatty acids, were suppressed by DIM treatment compared to irradiated samples. Together these data suggest that DIM reduces radiation-induced sequelae in the lung.

Keywords: pulmonary injury; ionizing radiation; radioprotectors, cancer; long term responses

Health Phys. 119(6):746-757; 2020

ASolutionforIterativeDeterminationofPatientReleaseInstructionsforFractionatedRadionuclide

Therapy

Garrett Otis1

(1. Yale New Haven Hospital, Radiation Safety Office, 20 York Street, Winchester Building, Room WW-229, New Haven, CT 06504)

Abstract:For fractionated radionuclide therapy protocols that involve large activities administered within short periods of time, there is a lack of guidance concerning how patient release calculations should be performed.Objectives:Present a solution for estimating the effective dose of individuals exposed to a patient undergoing fractionated radionuclide therapy; this is intended to be used for iterative determination of patient release instructions.Methods: The effective dose of an individual in the vicinity of a patient is described by a piecewise function that is integrated over periods of time that are defined by several variables relevant to clinical planning of fractionated radionuclide therapy protocols. This solution is compared to a simpler calculation that treats all administrations as identical events.Results:For the two compared methodologies, their equivalence for estimating effective dose depends on several variables. However, for protocols where the elimination time of the radionuclide is far smaller than the time between administrations, both methodologies produce essentially equal results.Conclusion:The author recommends using the presented solution for iterative determination of patient release instructions if a simpler approach generates release instructions that are overly restrictive. Doing so will allow for less strict release instructions because the dose mitigation from repeated adherence to release instructions after each fraction, in addition to potential inpatient time after each fraction, will be taken into account. Lastly, a spreadsheet that incorporates the presented solution has been made freely available for download.

Keywords: operational topics; effective dose; nuclear medicine; radiopharmaceuticals

Health Phys. 119(6):766-771; 2020

GuidanceNeededforContinuedEmploymentofLong-termContaminatedIndividuals

Lara R. Paciello1, Julian J. Owoc II2

(1.Beaver Valley Power Station, Route 168 Shippingport, PA 15077;2.Private Company [Confidential] Wampum, PA)

Abstract:Operational practices in nuclear power utilities often restrict job assignments for workers with internal contamination due to the difficulty of monitoring for new intakes and strict radioactive material controls. However, restriction of job assignments for an extended period (i.e., months to years) may be too conservative. An industry consensus on guidance in these conditions would be helpful for Radiation Safety Officers (RSOs) to allow long term contaminated workers to have less work restrictions.

Keywords: operational topics;60Co; dosimetry, internal dosimetry; inhalation

Health Phys. 119(6):772-775; 2020

AttenuationofGammaRadiationUsingClearViewRadiationShieldingTMinNuclearPowerPlants,HospitalsandRadiopharmacies

Jayeesh Bakshi, Bae P. Chu1

(1. Radium Incorporated, 463 Dinwiddie Avenue, Waynesboro, VA 22980)

Abstract:Radiation protection materials, such as lead (Pb), water, concrete, steel, and aluminum, have been successfully used for decades. Although they are effective shields, these materials do have limitations. For example, lead is heavy and toxic, and water and concrete must be thick to provide significant shielding, all of which renders these materials prohibitive for certain applications. For example, the half-value layer for water to shield against60Co is 30.48 cm (12″), which makes it an extremely bulky material. The development of ClearView Radiation ShieldingTMaddresses some of the limitations that are faced by traditional radiation protection shields. The product is a transparent liquid gamma radiation shield that can be fabricated in custom sizes and thicknesses. Here, we describe applications of ClearView Radiation Shielding in nuclear plants and hospitals. ClearView Radiation Shielding is used to shield nuclear power plant workers from60Co in critical path and high dose in refueling outages to observe automated operations inside the containment, and operations such as cylindrical frisking stations and benchtop sampling. ClearView Radiation Shielding is designed as rolling shields and radionuclide containments in hospitals to protect staff and families during unsealed radionuclide treatment such as MIBG and Lutetium therapies. For successful implementation in hospitals, the product was tested against various radioisotopes, also described in this work. Operational uses of ClearView Radiation Shielding in commercial nuclear and medical industries allows staff working in radioactive environments visibility, better communication and similar levels of radiation protection compared with traditional shielding materials. The product helps improve workflows and reduced total dose received by workers. Additionally, attenuation measurements using ClearView Radiation Shielding against multiple isotopes was performed. With 1.25 cm (0.5″) ClearView Radiation Shielding thickness, the shield attenuated 1) 65% of the effective dose from131I, 2) 35.15% of the effective dose from137Cs, and 3) 22.5% of the effective dose from60Co. Isotopes in the range of 35 keV to 1 899 keV. 3.81 were attenuated greater than 90% with a ClearView Radiation Shielding shield thickness of 7.62 cm (3″). The half-value layer for60Co with a ClearView Radiation Shielding thickness of 3.81 cm (1.5″) attenuated the effective dose of18F gammas by 85.59%. With a density of 2.3 g cm-3, ClearView Radiation Shielding was measured to be half the weight of lead for equal shielding. ClearView Radiation Shielding is transparent, lightweight, and an alternative material to conventional radiation shields to reduce radiation exposure.

Keywords: operational topics; exposure, occupational; nuclear medicine; waste management

Health Phys. 119(6):776-785; 2020