Health Phys. Abstracts，Volume 122,Number 4

ARiskComparisonbetweenLifestyle,SocioeconomicStatus,andRadiation:ACohortStudyofCancerMortalityamongJapaneseNuclearWorkers(J-EPISODE)

Shin’ichi Kudo1, Akemi Nishide1,2, Hiroshige Furuta1, Noboru Ishizawa1, Shin Saigusa1

(1.Institute of Radiation Epidemiology, Radiation Effects Association;2.College of Life Sciences, Ibaraki Christian University, Ibaraki, Japan)

Abstract:The health effects of low-dose radiation exposure have been a source of controversy. One possible reason is that epidemiological studies that compare radiation risk with other factors, such as lifestyle or socioeconomic status, have been limited. The aim of this study is to conduct a comparison of the cancer risk of mortality between radiation, lifestyle habits (such as smoking), and socioeconomic status (such as years of education) among Japanese nuclear workers. We assembled a cohort of 41,742 male nuclear workers in Japan who answered a lifestyle questionnaire survey conducted during 2003-2004. To exclude systematic errors caused by missing values, we used multiple imputation and Poisson regression to estimate relative risks and confidence intervals for lifestyle habits, socioeconomic status, and radiation. The total person-y from 2005 to 2010 were 215,000. The mean age and cumulative dose were 54.9 y and 24.8 mSv (10-y lagged dose), respectively. Significantly high relative risks were determined for smoking, alcohol consumption, frequency of medical examination, breakfast intake, sleep, and body mass index. Further, significantly high relative risks of radiation were shown for lung cancer and smoking-related cancers. Since the simultaneous inclusion of radiation and non-radiation variables in the model for relative risk (RR) calculation means that the calculated radiationRRis the result of adjustment by other variables, the risk of cancer from low-dose radiation, if any, is less than smoking and probably less than other lifestyle factors.

Keywords: cancer; epidemiology; radiation; low-level; risk estimates

Health Phys. 122(4):469-479; 2022

RetrievalandCharacterizationofaPlutonium-berylliumSourceattheUniversityofUtah

Codey Olson, William Bates, Edward Cazalas1

(1.Nuclear Engineering Program, Department of Civil and Environmental Engineering, University of Utah, 201 Presidents’ Circle, Salt Lake City, UT 84112)

Abstract:A shielded neutron irradiation facility has been constructed to contain a 74 GBq plutonium-beryllium neutron source at the University of Utah. Due to lack of information and recent use, the GEANT4 Monte Carlo Toolkit was used to perform dose assessments and validation of the designed shield and beam port for storage and operational geometries where the source was to be placed. Borated polyethylene was used as the primary shielding material with a lead-lined beam port to collimate neutrons and reduce gamma rays within the active beam profile. The lead lining was found to reduce the gamma-to-neutron ratio within the profile to 0.259±0.001 and maintain an average neutron flux of 4,633.7±10.2 cm-2s-1. The measured dose rate of the source at 30 cm from its constructed storage configuration was found to be 22.3±1.1 μSv h-1and in good agreement with simulated values. This was also close to the target rate of 20 μSv h-1, the public limit for whole-body dose accumulation, imposed on the design. Measurements of the source during its retrieval and placement into the shield show good agreement with the simulated results and provide a strong validation for the future use of the source in experiments at the University of Utah.

Keywords: Monte Carlo; neutrons; plutonium; shielding

Health Phys. 122(4):480-487; 2022

TheEffectoftheCoalIndustryonIndoorRadonConcentrationsineMalahleni,MpumalangaProvinceofSouthAfrica

Rikus le Roux1

(1.Stellenbosch University Saldanha, Western Cape, South Africa)

Abstract:South Africa has rich coal deposits concentrated in the northeast of the country, and as a result, most of the country’s coal mining is located in this region. Two of the principal coalfields exploited are the Witbank and Highveld coalfields, located in the Mpumalanga province. Coal contains trace quantities of the naturally occurring radionuclides whose mass concentration can be enhanced by anthropogenic activity. The radioactive fallout from these activities could lead to elevated radon concentrations indoors. Two towns, Secunda and eMalahleni, were identified due to their proximity to coal-based industries. A previous study investigated whether these industries caused elevated radon levels in Secunda homes but found a lower-than-expected average concentration of 76.4±7.6 Bq m-3. This was attributed to either the prevailing wind depositing the radioactive fallout to neighboring towns, such as eMalahleni, or the type of industrial activity. This paper builds on this study by investigating whether elevated radon levels are found in homes in eMalahleni. Measurements were performed in 22 homes during December 2019, and the average indoor radon concentration was calculated as 122.1±8.5 Bq m-3. The cause of these elevated levels was then investigated, and it was found that even though the coal industry contributes to elevated radon levels, the town’s underlying geology seems to be the primary contributor.

Keywords:222Rn; indoor; electrets; mining; coal; power plant; coal-burning

Health Phys. 122(4):488-494; 2022

AssessmentofOccupationalExposureinMedicalPracticeintheRegionofHohhot,China,forthePeriod2004-2020

Xiao Xu1, Shengnan Fan2, Xiaohao Tang3, Mengxue Li2, Xiang Liu4, Ziyang Zhang2, Shuai Zhang1, Zhichao Sun1, Jun Deng2

(1.Center for Comprehensive Disease Control and Prevention of Inner Mongolia Autonomous Region, Hohhot 010031;2. National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing 100088, China;3. China Institute of Atomic Energy, Beijing 102413, China;4. Hohhot Center for Disease Control and Prevention, Hohhot 010040)

Abstract:Individual monitoring is of great significance in efforts to protect the health of radiation workers and improve the level of radiation protection and management. This paper presents a retrospective analysis of occupational exposure to ionizing radiation from medical practice in the region of Hohhot, China, from 2004 to 2020. Results show that the average annual effective dose of occupationally exposed workers in medical practice significantly declined from 1.44 mSv in 2005 to 0.29 mSv in 2020 (Z=-5.23,P<0.05). The number of medical radiation workers increased by 181%, the composition of radiation workers whose average annual effective dose exceeded 1 mSv decreased, and the number of radiation workers whose average annual effective dose was less than or equal to the minimum detection level (MDL) increased yearly over the 17-y study period. It was found that the dose of 1.106 mSv received by workers in interventional radiology is significantly higher than the doses of 0.52 mSv in dental radiology, 0.47 mSv in radiotherapy, and 0.33 mSv in all other medical uses (Z= 3.71, 9.13, 5.93, respectively;P< 0.05). The distribution ratios of workers in nuclear medicine and interventional radiology whose annual individual effective dose exceeded 5 mSv were 0.040 and 0.043, respectively, which are significantly higher than those in other occupational categories (χ2= 307.11,P< 0.05). It was also shown that the average annual effective dose of 0.67 mSv in interventional radiology is significantly higher than that of 0.17 mSv in radiotherapy (Z= 3.39,P< 0.05) in 2020. According to these observations, the exposure of radiation workers in medical practice in Hohhot meets the requirements of the China standard. This study shows that the status of radiation workers in medical practice has obviously improved during the period 2004-2020. However, it is still necessary to focus on the protection of groups with high occupational exposure risk, and the continuous improvement of protection measures, monitoring means, and radiation workers’ training, especially for the workers in the fields of interventional radiology and nuclear medicine.

Keywords: dose assessment; effective dose; exposure; occupational; medical radiation

Health Phys. 122(4):495-501; 2022

InvestigationofRadionuclideMigrationatSitesAdjacenttothe30kmExclusionZoneoftheChernobylNuclearPowerPlant

V. A. Zheltonozhskyi1, M. V. Zheltonozhskaya2, D. E. Myznikov1, 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. Center for Nuclear Studies-Nuclear Energy, Science and Engineering Laboratory, Kennesaw State University, Marietta, GA)

Abstract:This paper reports the study of the vertical migration of radionuclides in soils at test sites adjacent to the 30 km Chernobyl Exclusion Zone. The results of this effort demonstrate that the migration processes for studied pollution occur similarly to the fuel fallout behavior at the vicinity of the Chernobyl Nuclear Power Plant (ChNPP) Unit 4. It was also observed that the main fallout component,137Cs, originated from aerosol fallout and was bound in the surface layer. The authors determined a significant increase of60Co,94Nb, and241Am radionuclide concentrations in soils near the ChNPP Unit 4 and suggested their appearance due to the installation of the New Safe Confinement. Niobium-94 activity is proposed as a marker for monitoring the “fresh” fallout in the Chernobyl Exclusion Zone.

Keywords:137Cs; Chernobyl; contamination; environmental; fallout

Health Phys. 122(4):502-507; 2022

Ramsar,Iran,asaNaturalRadiobiologicalSurrogateforMars

James S. Welsh, Joseph J. Bevelacqua, S.M.J. Mortazavi1

(1.Department of Radiation Oncology, Loyola University Chicago Stritch School of Medicine and Edward Hines Jr. VA Medical Center, 5000 S 5th Ave., Hines, IL)

Abstract:Terrestrial experiments involving acute exposures of low-LET radiation on inbred lab animals are quick, simple, and inexpensive but are relatively uninformative about the real radiobiological hazards of planned manned space missions. A more predictive model could involve human beings chronically exposed to “space-like” high-LET radiation. Such radiation exposure has been ongoing for thousands of years in Ramsar, Iran, and some other high-LET high background radiation regions on Earth. Examining the health of Ramsar residents can be illuminating and potentially relevant to space missions.

Keywords: health effects; radiation, background; radiation; low-level; radiation protection

Health Phys. 122(4):508-512; 2022

RadiopharmaceuticalExtravasation:PragmaticRadiationProtection

Darrell R. Fisher1, Misty Liverett2

(1.Versant Medical Physics and Radiation Safety 229 Saint Street Richland, WA 99354;2. Versant Medical Physics and Radiation Safety)

Abstract:Inadvertent injection of a radiopharmaceutical agent into a patient’s arm tissue instead of into the appropriate blood vessel can cause the injection to infiltrate underlying tissue and produce a potentially substantial, localized irradiation to the patient's arm and skin tissue. When this type of misadministration occurs, called an extravasation, it should be recognized, mitigated, and monitored for patient health and safety. Immediate symptoms of radiopharmaceutical extravasation may include swelling, edema, pain, or numbness in the vicinity of the extravasation site; inflammation; and drainage from the site. Some infiltrations may go unnoticed until later. Pragmatic elements of radiation safety include imaging to assess the geometry, volume, and anatomic distribution of activity, collection of tissue count-rate data over retention times, calibration against known activity levels, and dosimetry to help clinicians determine whether an extravasation is severe and whether the patient should be followed for adverse tissue reactions.

Keywords: radiopharmaceutical extravasation; event characterization; dose assessment; radioactivity; radiation protection; external measurements

Health Phys. 122(4):537-539; 2022

RadiationDosetoVeterinariansandVeterinaryTechniciansDuringRadioiodineTreatmentofFelisCatus

Meghan M. Dieffenthaller, Thomas E. Johnson1

(1.Colorado State University, Department of Environmental and Radiological Health Sciences Fort Collins, CO 80523)

Abstract:The uptake of radioiodine in veterinarians or veterinary staff when131I is administered via injection to domesticated cats (Feliscatus) with hyperthyroidism has not been well studied. Veterinarians and staff undergo specific training for the handling of radioiodine injection of cats to minimize and prevent an inhalation intake. An in-vivo bioassay is performed post cat injection to determine if131I was inhaled or absorbed. The frequency of in-vivo bioassays requires dedicated time of the veterinarians and those who must perform the bioassay. Bioassay data from veterinarians and staff at the Colorado State University Veterinary Teaching Hospital administering131I from the past 20 years were analyzed (n=168) to ascertain if there is a correlation between the amount of time elapsed between the131I administration, the bioassay, and the net counts resulting from the bioassay. The amount of131I administration and the bioassay net counts were also analyzed to determine if there was a correlation. No correlations were found, and out of 168131I administrations over 20 years, only 3 bioassays resulted in measurable doses of131I with a committed dose equivalent (CDE) of 0.19 mSv, 0.77 mSv, and 1.6 mSv. The current precautions taken to prevent the inhalation intake of131I appear sufficient to consider changing the requirements for veterinary bioassay after routine administration of131I to cats.

Keywords: bioassay; radiation dose; radiation； medical; thyroid

Health Phys. 122(4):544-547; 2022

Dose-TrackingSoftware:ARetrospectiveAnalysisofDosimetricDatainCTProcedures

Mauro Buono1, Tiziana Capussela2, Filomena Loffredo3, Maria Antonella Di Pasquale2, Marcello Serra1, Maria Quarto3

(1.School of Specialization in Medical Physics, University of Naples Federico II, Naples;2. U.O.S.D. Health Physics, AORN Cardarelli Hospital, Naples;3. Advanced Biomedical Science Department, University of Naples Federico II, Naples, Italy)

Abstract:The increasing use of ionizing radiation in healthcare is causing growing alarm about radiation protection of patients and the doses they receive during procedures. Radiation dose assessment for patients in radiodiagnostic procedures is the subject of interest in view of the recent Italian D.Lgs 31 July 2020, n. 101 (Decreto Legislativo 31 luglio 2020, n. 101) and one of its most important focuses is the prescription to provide patient exposure information as an integral part of the examination report. Dose monitoring systems are therefore essential for the collection of the dosimetric data. In order to analyse potential and critical issues of these software, different systems, adopted at the Antonio Cardarelli Hospital in Naples, were employed. Data extracted from the DoseWatch software (GE Healthcare) and Gray Detector (EL.CO. S.r.l. Healthcare Solutions, Italy) and relating to several protocols adopted for computed tomography (CT), were retrospectively analysed for the purpose of identifying critical issues in the data acquisition and recording phase, comparing with Italian nationwide diagnostic reference levels (DRLs), as provided for in regulatory provisions for radiation safety. Multiphase examinations were also included in this study. Once the distributions of volumetric CT Dose Index (CTDIvol) and dose-length product (DLP) were determined for each acquisition phase and totalDLP(DLPtot) for each examination, the 25th, 50thand 75thpercentiles were calculated for each distribution and then compared with the relevant Italian nationwideDRLs. In addition, to improve protocol optimization and dose reduction the magnitude of the CT acquisition settings chosen in each procedure was evaluated. In conclusion, these systems allow accurate analysis of radiation dose according to equipment and protocol over time. For the application of optimization measures, a constant use of the dose tracking software is required, which can be translated into actions on scan parameters and prospective data analysis.

Keywords: nuclear medicine; bioassay;131I; thyroid

Health Phys. 122(4):548-555; 2022