Health Phys. Abstracts，Volume 121,Number 2

StudyonthePerformanceofanAlphaEnergySpectrumRadonMeasuringInstrumentBasedonCdZnTeDetector

Songsong Li,Jian Shan,Songbo Tan1

(1.School of Nuclear Science and Technology,University of South China,Hengyang,Hunan,421001,China)

Abstract:To realize a fast and reliable approach for continuous radon measurements,a CdZnTe (CZT)detector based on the electrostatic collection method was developed.The experimental results show that when the external temperature varies from 5 ℃ to 30 ℃,the maximum drifts of the characteristic peak positions of218Po and214Po are only 8 and 6.Furthermore,the measurement error associated with the constant radon concentration is less than 5.5%.As the temperature increases or decreases,the measurement error becomes larger,with the maximum error being 43.1%.The response of the proposed instrument for constant radon concentration is better than that of the RAD7 radon measurement instrument.At 25 ℃,the value measured using the NRL-II radon meter with the PIPS detector is in good agreement with the actual value.The new radon measurement instrument exhibits a good compliance from the third measurement cycle (measurement deviation 0.53%-3.95%),while RAD7 has good compliance from the fourth measurement cycle (measurement deviation of 1.17%-4.88%).The theoretical and practical values of the iterative correction factor (influence of the previous measurement on the current measurement)of the radon measurement instrument are in good agreement.The iterative correction factor can be used for performing continuous radon measurements independently,with the aim of achieving a rapid response to environmental radon concentrations.

Keywords:222Rn;detector;alpha-track;instrumentation;radon

Health Phys.121(2):87-91;2021

BiomarkersofAtheroscleroticVascularDiseaseinWorkersChronicallyExposedtoIonizingRadiation

Darya Oslina,Valentina Rybkina,Galina Adamova,Galina Zhuntova,Maria Bannikova,Tamara Azizova1

(1.Federal State Unitary Enterprise “Southern Urals Biophysics Institute”at the Federal Medical Biological Agency of the Russian Federation,Ozyorskoe shosse 19,Ozyorsk Chelyabinsk Region,456780 Russia)

Abstract:It is well established that cohorts of individuals exposed to ionizing radiation demonstrate increased risks of cardio-and cerebrovascular diseases.However,mechanisms of these radiation-induced diseases developing in individuals exposed to ionizing radiation remain unclear.To identify biomarkers of the atherosclerotic vessel damage in workers chronically exposed to ionizing radiation,this study considered 49 workers of the Russian nuclear production facility—the Mayak Production Association (mean age of 68.73 ± 6.92 years)—and 38 unexposed individuals (mean age of 68.84 ± 6.20 y)who had never been exposed to ionizing radiation (control).All workers were chronically exposed to combined radiation (external gamma rays and internal alpha particles).The mean cumulative liver absorbed dose from external gamma-ray exposure was 0.18 ± 0.12 Gy;the mean cumulative liver absorbed dose from internal alpha-particles was 0.14 ± 0.21 Gy.Levels of biomarkers in blood serum of the study participants were measured using the ELISA method.Elevated levels of apolipoprotein B,superoxide dismutase,monocyte chemoattractant protein 1,vascular cell adhesion protein 1,and a decreased level of endothelin-1 were observed in blood serum of Mayak PA workers chronically exposed to combined radiation compared to control individuals.A significant positive correlation was demonstrated between the vascular cell adhesion protein 1 level and cumulative liver absorbed doses from external gamma radiation and internal alpha radiation.Findings of the study suggest that molecular changes in blood of individuals occupationally exposed to ionizing radiation (combined internal exposure to alpha particles and external exposure to gamma rays)may indicate dyslipidemia,oxidative stress,inflammation,and endothelial dysfunction involved in atherosclerosis development.

Keywords:exposure;occupational;health effects;radiation;alpha;radiation;gamma

Health Phys.121(2):92-101;2021

EvaluationofTriageMethodsforCriticalityAccidents

K.G.Veinot1,B.T.Gose2

(1.Y-12 National Security Complex,P.O.Box 2009,M.S.8105,Oak Ridge,TN 37831-8105;2.Indepdendent Researcher,Knoxville,TN)

Abstract:Studies indicate that early identification of persons involved in and receiving high doses of radiation in accidents is key to providing life-saving medical treatment.Although the risk of criticality accidents is low,the potential impact to workers is significant.For facilities that employ large numbers of workers,a key element in the response to a radiological emergency is identifying personnel that received significant and potentially harmful doses.Also important is having the ability to screen large numbers of workers to identify persons who did not receive significant exposure so as to reduce the impact on emergency response efforts.At the Y-12 National Security Complex,the focus on criticality accident response is the rapid triage of personnel in order to identify persons exposed to large radiation doses and to prioritize those persons receiving the highest exposures.Once identified,personnel are transported to local medical facilities,including the Radiation Emergency Assistance Center/Training Site (REAC/TS),for medical evaluation and treatment.The Y-12 external dosimetry program uses a number of techniques to identify and prioritize workers,and these methods were evaluated at a criticality dosimetry intercomparison exercise.The methods used were shown to perform as intended,and other sites may consider incorporating these methods into their accident dosimetry response procedures.

Keywords:accidents;nuclear;dose;emergencies;radiological;health effects

Health Phys.121(2):102-110;2021

TheAnthropogenicImpactonIndoorRadonConcentrationsforSecunda,MpumalangaProvince,SouthAfrica

Rikus le Roux1,Jacques Bezuidenhout1,Hennie Smit1,Richard Newman2

(1.Faculty of Military Science,Stellenbosch University,Stellenbosch,South Africa;2.Department of Physics,Stellenbosch University,Stellenbosch,South Africa)

Abstract:Secunda is a town built amid the coalfields of the Mpumalanga province of South Africa.Surrounding the town are 11 coal-fired plants (CFPs)contributing around 59% of the country’s energy needs.It is also home to Sasol Synfuels,which produces synthetic gas through coal gasification and natural gas reforming.Coal,like most materials found in nature,contains trace elements of the naturally occurring primordial radionuclides40K,238U,232Th,and their decay products.The milling and combustion of coal in a CFP increases the mass concentration of these trace elements,and the residuals end up on ash heaps as fly ash,bottom ash,and boiler slag.A small percentage of fly ash also ends up in the atmosphere.This paper sets out to determine the anthropogenic impact of the industrial activity on indoor radon in the town of Secunda in the Mpumalanga region of South Africa.Measurements were done in 37 homes during July when higher indoor radon levels are expected due to homes typically being closed due to the low temperatures.The average indoor radon concentration was found to be 76.4 Bq m-3.This indicates that the fallout from the industrial activity surrounding Secunda does not enhance the emanation of radon.This may be due to the type of activity or the climate and prevailing winds mitigating its indoor build-up.Measurements during the warmer months and in neighboring towns with different industrial activities are required to confirm the trends established by this research.

Keywords:fly ash;mining,coal;power plant;coal burning;radon

Health Phys.121(2):111-116;2021

RadonConcentrationsinaNuclearReactorCenterinBrazil

Paulo Sergio Cardoso da Silva1,Marcia Pires de Campos1,Thammiris Mohamad El Hajj2,Guilherme de Lima Reis1

(1.Instituto de Pesquisas Energéticas e Nucleares (IPEN /CNEN-SP),Av.Professor Lineu Prestes 2242,05508-000 São Paulo,SP,Brazil;2.Universidade Federal de Alfenas (UNIFAL-MG),Rodovia José Aurélio Vilela,11999,37715-400 Poços de Caldas,MG,Brazil)

Abstract:Radiation workers are normally exposed to doses resulting from their day-to-day activities.Besides that,background radiation,such as radon,can contribute to the exposure rates.The radionuclide222Rn is a noble gas belonging to the uranium series,and its indoor concentration in the air depends on the exhalation from surrounding soil and the exhalation from building materials.Radon exhaling from porous building materials containing high uranium concentrations can become a significant exposure factor in areas with limited ventilation.The objective of this study was to evaluate the222Rn concentrations in the radiochemistry and radiometric laboratories in the nuclear reactor building of the Nuclear Reactor Center (CERPq)located in the Institute of Nuclear and Energy Research (IPEN),São Paulo,Brazil.Measurements were done using a Radon Gas Monitor,model RAD7,equipped with a solid-state alpha detector.A passive method (SSNTD)was also used,consisting of square pieces of CR-39 foils (2.5 cm × 2.5 cm)placed within small diffusion chambers.The CR-39 detectors were etched in KOH 30% solution at 80 ℃ for 5.5 h in a constant-temperature bath.After etching,the detectors were washed,dried,and scanned using a microscope to obtain the track density measurements.The activity concentrations measured with both techniques varied from 52 to 103 Bq m-3in the studied areas of the CERPq.These values may be compared to the reference level of 100 Bq m-3established by the World Health Organization to ensure safety environments.

Keywords:222Rn;exposure;occupational;nuclear reactor

Health Phys.121(2):117-123;2021

PreliminaryThermoluminescentDosimeterGlowCurveAnalysiswithAutomatedGlowPeakIdentificationforLiF:Mg,Ti

Jack H.Thiesen,Jeremy M.Hepker,Wenjin Yu,Keegan D.Pombier,Kimberlee J.Kearfott1

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

Abstract:When appropriately analyzed,thermoluminescent dosimeter glow curve analysis allows for improved quantification of thermoluminescent material behavior while flagging abnormalities.The mathematical separation of a glow curve into contributions from energetically unique trap states,or glow curve analysis,may be used to remove undesired effects of signal fading for complex materials.A generalized glow curve analysis software for the separation of glow curves is presented in this paper.Written in C++,the software uses the first-order kinetics model with automatic peak identification.The automatic identification of peaks is achieved through a unique peak-finding algorithm.The program was performance tested using experimental glow curve data from LiF:Mg,Ti,and comparative results are presented.

Keywords:analysis;statistical;dosimetry,thermoluminescent;kinetics;quality assurance

Health Phys.121(2):124-132;2021

EstimationoftheEarlyCs-137IntakeofEvacueesfromAreasAffectedbythe2011FukushimaDaiichiNuclearPowerPlantAccidentBasedonPersonalBehavioralDataandtheLatestAtmosphericTransportandDispersionModelSimulation

Eunjoo Kim1,Yu Igarashi1,2,Shozo Hashimoto1,Kotaro Tani1,Tetsuo Ishikawa3,Munehiko Kowatari1,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)

Abstract:More than 9 y have passed since the 2011 nuclear disaster in Fukushima Prefecture,Japan.During this period,much effort has been spent on the dose reconstruction for Fukushima residents;however,the estimation of the internal dose due to the potential intake of the short-lived radionuclides (mainly iodine-131)has been challenging because of the lack of direct human measurements at the early phase of the accident.Our previous study revealed that the residual cesium body contents observed in delayed whole-body counter (WBC)measurements of residents from Namie-town,one of the most affected municipalities,varied greatly with the timepoint of their evacuations on 12 March 2011 when the first explosive event occurred at the accident site;i.e.,the late evacuees had much higher residual cesium body contents compared to the prompt evacuees.The present study thus aimed to clarify this finding by reproducing the exposure situation based on the evacuees' personal behavioral data in combination with the latest atmospheric transport and dispersion model (ATDM)simulation for 356 selected subjects in adult and 15 y (13-17 y)age groups.The results demonstrated that the ATDM simulation-based method could reasonably reproduce the subjects’exposure situation,supporting the previous finding.However,the residual Cs-137 body contents calculated by this method were only 10%-20% of those in the subjects’WBC measurements.This large discrepancy was considered to be caused by both the present method’s underestimation and the overestimation of the subjects’early intake in the WBC measurements due to a conservative intake scenario not assuming potential additional intake.Additional studies are needed to further clarify the reasons for the discrepancy and to evaluate the magnitude of the inhalation dose in the accident.

Keywords:137Cs;dosimetry;internal;Fukushima Daiichi;radiation;atmospheric

Health Phys.121(2):133-149;2021

AnisotropyoftheRadiationFieldFollowingCanineSn-117mTreatment

Matthew G.Arno1,Jaime Simon2,Nigel Stevenson3,John Donecker3

(1.Foxfire Scientific,Arlington,TX;2.IsoTherapeutics Group,LLC,Angleton,TX;3.Exubrion Therapeutics,Buford,GA)

Abstract:Tin-117m (117mSn)is used to treated dogs with osteoarthritic joints by radiosynoviorthesis.The internal conversion and Auger electrons emitted by the117mSn provide the therapeutic effect.Sn-117m also emits gamma rays,of which the most significant is 158.6 keV.The external radiation field around a treated dog is of interest to limit the dose to the owners/caretakers of the dog.The dog’s torso attenuates the radiation being emitted toward the opposite side of the dog’s body.This leads to a radiation field that is significantly non-isotropic.This study characterizes the anisotropy of this field to permit maximum dose rate measurements to be used to calculate the dose to individuals in the vicinity of the dog.Measurements were made in nine directions and at two distances,0.3 and 1.0 m,to characterize common distances and spatial orientations for human-dog interactions.From these measurements,the percent reduction in the average dose rate compared to the maximum dose rate was determined.From a radiation safety perspective,the important factor is the minimum amount of shielding effectiveness or percent reduction that can be expected.A reasonable measure for this value is the fifth percentile of the shielding effectiveness distribution.The fifth percentile shielding effectiveness measures are 27% and 21% at 0.3 and 1.0 m,respectively.

Keywords:dose assessment;radiation protection;radiation therapy;radioisotope

Health Phys.121(2):150-155;2021

PatientReleaseandInstructionsforLutetiumDotatateRadiopharmaceuticalTherapy

James Underwood1,2,Glenn Sturchio3,Susan Arnold2

(1.Mayo Clinic,200 First Street S.W.,Rochester,MN 55905;2.Division of Environmental Health Sciences School of Public Health,University of Minnesota MMC 807,Room 1239 Mayo,420 Delaware Street SE Minneapolis,MN 55455;3.Mayo Clinic,4500 San Pablo Road,Jacksonville,FL 32224)

Abstract:Lutetium Dotatate radiopharmaceutical therapy (Lutathera)was approved by the United States Food and Drug Administration in 2018 and is used to treat somatostatin receptor positive neuroendocrine tumors.With all new radiopharmaceutical therapies,the radiation exposure to members of the public from the patient who received the therapy must be within regulatory limits and safe.If the patient will expose members of the public to too much radiation,the therapy must be performed on an inpatient basis.This paper shows that the administration of Lutathera can be done on an outpatient basis and provides safety and travel restrictions that should be communicated to the patient prior to leaving.The guidance presented herein serves as a basis for medical institutions looking to use Lutathera to treat patients.

Keywords:operational topics;nuclear medicine;radiation protection;radiopharmaceuticals

Health Phys.121(2):160-165;2021

Students’andQualifiedRadiographers’PerspectivesandUnderstandingonOccupationalDoseMonitoringandPreventionStrategies

Chandra R.Makanjee,Erin Lipscombe,Adrianna Niza Haniz,Yun Sook Cho1

(1.Department of Medical Radiation Sciences,Faculty of Health,University of Canberra,Australian Capital Territory,Australia)

Abstract:Effective implementation and ongoing monitoring of occupational radiation safety and protection is key for radiographers as prolonged exposure to ionizing radiation can increase the risk of long-term ill health effects.It is important that radiographers are aware of what is required of them to remain within the permitted dose limit.Topics and training on dose monitoring and occupational practice safety and practice are embedded in both undergraduate and postgraduate courses and ongoing as part of continuous professional development.However,whether these are accurately,effectively implemented and adhered too in practice needs to be monitored.This study aimed to investigate students and radiographers’awareness,observations,and understandings of their compliance to occupational radiation safety and protection and monitoring thereof in the clinical setting.A cross sectional survey design with a questionnaire consisting of closed and open-ended items were used.The data were analysed with the use of SPSS statistical software tool.The response rates for student radiographers were 62% and qualified radiographers 23.19%.Most participants indicated that they were knowledgeable on best practice methods regarding radiation protection and safety.However,regarding the importance of personal monitoring devices,the responses varied and there were some inconsistencies.The perspectives of participants on rotating through different imaging examination types revealed that of least importance was the occupational exposure.Students were focused as part of their training on acquiring the necessary skills to conduct imaging examinations.Qualified radiographers focused on upkeeping their skills when it came to their rotation between the general and specialized imaging examinations.To overcome some of these inconsistencies it is recommended that standardized practice guidelines be reviewed by both the academic institution and the clinical training sites enforcing the importance of dose monitoring and radiation safety and best practice principles.

Keywords:occupational topics;dosimetry;personnel;imaging;radiation protection

Health Phys.121(2):166-173;2021