In the event of a radioactive dispersal device (RDD), the assessment of the internal contamination level of victims is necessary to determine if immediate medical follow-up is necessary. Thermo Scientific's TPM-903B Portal Monitor was investigated to determine if it is a suitable first cut screening tool for internal contamination assessment of victims. A portal monitor was chosen for this study because they are readily accessible, transportable, easy to assemble, and provide whole body count rates due to the detector size. The TPM-903B was modeled in Monte Carlo N-Particles Transport Code Version 5 (MCNP). This computational model was validated against the portal monitor's response to a series of measurements made with four point sources in a polymethyl methacrylate (PMMA) slab box. Using the validated MCNP5 model and models of the MIRD male and female anthropomorphic phantoms, the response of the portal monitor was simulated for the inhalation and ingestion radionuclides from an RDD. Six representative phantoms were considered: Reference Male, Reference Female, Adipose Male, Adipose Female, Post-Menopausal Adipose Female, and 10-Year-Old Child. The biokinetics via Dose and Risk Calculation Software (DCAL) was implemented using both the inhalation and ingestion pathways to determine the radionuclide concentrations in the organs of the body which were then used to determine the count rate of the portal monitor as a function of time. Dose coefficients were employed to determine the count rate of the detector associated with specific dose limits. These count rates were then compiled into procedure sheets to be used by first responders during the triaging of victims following an RDD.

A ce jour, l’évaluation des risques associés à l’incorporation de radionucléides et l’élaboration des normes de radioprotection en résultant sont principalement basées sur les résultats du suivi épidémiologique de populations exposées aux rayonnements ionisants par voie externe. Les analogies et extrapolations employées dans cette démarche sont entourées d’incertitudes. Afin de pouvoir évaluer la validité des hypothèses retenues dans ce cadre par la Commission Internationale de Protection Radiologique, il est nécessaire de réaliser de nouvelles études épidémiologiques au sein de populations exposées à des émetteurs internes. C’est notamment le cas pour ce qui concerne les expositions à l’uranium, dont les effets sanitaires potentiels demeurent mal caractérisés. Par ailleurs, alors que les effets cancérigènes des radiations ionisantes sont établis et de mieux en mieux caractérisés, l’hypothèse d’un effet de faibles doses de rayonnements ionisants sur le développement de maladies de l’appareil circulatoire a été émise récemment, et demande à être évaluée de manière approfondie.L’objectif de cette thèse est de contribuer à améliorer la connaissance des effets sanitaires des expositions chroniques à de faibles doses de rayonnements ionisants, en particulier du fait de contamination internes par l’uranium, en support à l’évaluation et si nécessaire à la consolidation des normes internationales de radioprotection.La thèse s’articule autour de trois axes:- L’analyse de la mortalité dans une cohorte de 1300 travailleurs d’usines de traitement du minerai d’uranium (F-MILLERS), par comparaison avec la mortalité de la population générale française par calcul de rapports de mortalité standardisés.- L’analyse de l’association entre la dose (interne et externe) et la mortalité par cancers et maladies cardiovasculaires dans une cohorte de 4000 travailleurs de l’uranium: Analyse statistique classique (fréquentiste) incluant une exploration détaillée de l’impact de potentiels facteurs confondants individuels rarement disponibles dans d’autres cohortes de travailleurs du nucléaire (ex: obésité, tabagisme, tension artérielle).- Le développement d’une approche hiérarchique bayésienne permettant de tenir compte des incertitudes engendrées par l’estimation de la dose interne à partir de mesures radiotoxicologiques fortement censurées à gauche (i.e., inférieures à un seuil) dans l’estimation de risques sanitaires radio-induits, basée sur cette dose. / Nowadays, the assessment of the risks associated with the incorporation of radionuclides and the resulting development of radiological protection standards are mainly based on the results of the epidemiological monitoring of populations exposed to external ionizing radiation. The analogies and extrapolations used in this process are surrounded by uncertainties. In order to be able to evaluate the validity of the assumptions adopted in this context by the International Commission on Radiological Protection (ICRP), it is necessary to conduct new epidemiological studies in populations exposed to internal emitters. This is particularly the case for uranium exposures, whose potential health effects remain poorly characterized. Moreover, while the carcinogenic effects of ionizing radiation are established and increasingly well characterized, the hypothesis of an effect of low doses of ionizing radiation on the development of diseases of the circulatory system has been suggested recently, and requires to be evaluated thoroughly.The aim of this PhD thesis project is to improve the knowledge of the health effects of chronic internal exposure to low doses of ionizing radiation, particularly due to internal contamination by uranium, in support of the evaluation and if necessary to the consolidation of international radiation protection standards.The PhD thesis project includes three axes:- Analysis of mortality in a new cohort of 1,300 workers employed by uranium-milling companies, by comparison with the mortality of general French population by computing standardized mortality ratios.- Analysis of the association between dose (internal and external) and mortality from cancer and cardiovascular diseases in a cohort of 4,000 uranium workers: classical statistical analysis (frequentist) included detailed exploration of the impact of potential confounding factors rarely available in other cohorts of nuclear workers (e.g.: obesity, smoking, blood pressure)- Development of a Bayesian hierarchical approach allowing to account for uncertainties induced by the estimation of internal dose from radiotoxicological measurement that are strongly left-censored (i.e., lower than a threshold) in radiation-induced risk estimates, based on this dose.

In the event of a nuclear power plant accident, fission products could be released into the atmosphere potentially affecting the health of local citizens. In order to triage the possibly large number of people impacted, a detection device is needed that can acquire data quickly and that is sensitive to internal contamination. The portal monitor TPM-903B was investigated for use in the event of a fission product release. A list of fission products released from a Pressurized Water Reactor (PWR) was generated and separated into two groups--Group 1 (gamma- and beta-emitting fission products) and Group 2 (strictly beta-emitting fission products.) Group one fission products were used in the previously validated Monte Carlo N-Particle Transport Code (MCNP) model of the portal monitor. Two MIRD anthropomorphic phantom types were implemented in the MCNP model--the Adipose Male and Child phantoms. Dose and Risk Calculation software (DCAL) provided inhalation biokinetic data that were applied to the output of the MCNP modeling to determine the radionuclide concentrations in each organ as a function of time. For each phantom type, these data were used to determine the total body counts associated with each individual gamma-emitting fission product. Corresponding adult and child dose coefficients were implemented to determine the total body counts per 250 mSv. A weighted sum of all of the isotopes involved was performed. The ratio of dose associated with gamma-emitting fission products to the total of all fission products was determined based on corresponding dose coefficients and relative abundance. This ratio was used to project the total body counts corresponding to 250mSv for the entire fission product release inhalation--including all types of radiation. The developed procedure sheets will be used by first response personnel in the event of a fission product release.

This study is engaged in express emergency methods to monitor internal contamination of people in the event of the radiological emergency.

I nuklearmedicinska verksamheten utsätts personal för strålning på olika vis. Huvudsakligen genom administrering av radiofarmaka som injicering eller avfallshantering men även genom att befinna sig nära patient efter injektion av radiofarmaka. Med strålning finns risker för skador som förekommer i cellnivå. Två typer av effekter förekommer vid bestrålning av vävnaden, deterministiska och stokastiska skador. För att minska risken för skador har strålsäkerhets-myndigheten (SSM) föreskrivit dosgränser som inte får överskridas. Syftet med studien var att kartlägga stråldoser till personal inom nukleamedicinska verksam-het. I studien kontrollerades fingerdoser för personal inom PET/CT, där små termoluminiscenta dosimetrar (TLD) placerades på sex fingertoppar hos personal-en. Stråldoserna mättes vid tre arbetstillfällen; uppackning av 18F, injicering med automatisk injektor samt manuellt uppdrag och injicering av 18F märkt läkemedel. För att fastfälla risken för internkontamination av personal vid ventilationsunder-sökningar med 99mTc-aresol, placerades personalen under en gammakamera och antalet pulser som fastställdes översattes till aktivitet genom en fantommätning. Dessutom mättes doshastigheten hos patienter injicerade med 18flour märkta läke-medel. Ett dosratinstrument (Ram GENE mark iii) användes för att mäta dos-hastigheten vid sju olika mätpunkter och tre olika avstånd. Enligt resultaten upp-nådde ingen SSM’s dosgränser. Skillnad mellan injicering manuellt och med auto-matisk injektor visade en stor variation vid erhållna resultat. Dosratmätningarna visade en mycket tydlig sänkning för varje gångavstånd ökade. Mätningarna för internkontamination visade att personalen inte utsattes för höga stråldoser med avseende på internkontamination. Den minsta detekterbara aktivitet var 0,0008 MBq. Det som konstateras utifrån studien är att hantering 18F ger högre stråldoser än 99mTc (200 keV), då den har en mycket högre fotonenergi (511 keV). / Working staff in nuclear medicine are exposed for radiation in different ways. Mainly by the administration of radiopharmaceuticals, such as injection or dis-posal, even by being close to the patient after injection of radiopharmaceuticals. With radiation there are risks of damage occurring at the cellular level. Two types of effects are found in the irradiation of tissues, deterministic and stochastic injuries. To reduce the risk of injury, the Swedish radiation safety authority (SSM) has prescribed dose limits that cannot be exceeded. Among other doses, there are limits for the fingers per year. The purpose of the study was to control radiation doses to personnel working in nuclear medicine. In the study finger doses were controlled for personnel within PET / CT, where thermoluminescent dosimeters (TLDs) were placed at six fingertips. Radiation doses were measured at three moments; unpacking of 18F, injection with automatic injector and manual injection of 18F labeled drug. To determine the risk of internal contamination of personnel that performs ventilation studies with 99mTc aresol, staff were placed under a gamma camera and the number of pulses detected were translated into activity through measurement of a radiation source (cylinder filled with known activity). In addition, the dose rate was measured around patients injected with 18flour-labeled drugs. A dose rate detector (Ram GENE mark iii) was used to measure the dose rate at seven different measuring points and three different distances. Difference between injection manually and with automatic injector showed a large variation in results obtained and SSM’s dose limits weren’t reached. The dose rate measurements showed a very clear reduction for each time the distance increased. Internal contamination measurements showed that staff were not exposed to high radiation doses regarding internal contamination and the least detectable activity was 0.0008 MBq. The study showed that handling 18F produces higher radiation doses than 99mTc (200 keV), as it has a much higher photon energy (511 keV).