The objective of this project was to develop a simple MCNPX model of the human eye to approximate dose delivered from proton therapy. The calculated dose included that due to proton interactions and secondary interactions, which included multiple coulombic energy scattering, elastic and inelastic scattering, and non-elastic nuclear reactions (i.e., the production of secondary particles). After benchmarking MCNPX with a known proton simulation, the proton therapy beam used at Laboratori Nazionali del Sud-INFN was modeled for simulation. A virtual water phantom was used and energy tallies were found to correspond with the direct measurements from the therapy beam in Italy. A simple eye model was constructed and combined with the proton beam to measure dose distributions. Two treatment simulations were considered. The first simulation was a typical treatment scenario-where dose was maximized to a tumor volume and minimized elsewhere. The second case was a worst case scenario to simulate a patient gazing directly into the treatment beam during therapy. Dose distributions for the typical treatment yielded what was expected, but the worst case scenario showed the bulk of dose deposited in the cornea and lens region. The study concluded that MCNPX is a capable platform for patient planning but laborious for programming multiple simulation configurations.

Naturally occurring radioactive material (NORM) exists in connate waters and, under the right conditions during oil drilling, can plate out on the interior surfaces of oil and gas industry equipment. Once deposited, this material is commonly referred to as ??scale.?? This thesis is concerned with the presence of 226Ra in scale deposited on the inner surfaces of oil drilling pipes and the internal dose consequences of inhalation of that scale once released. In the process of normal operation, barium sulfate scale with a radium component adheres to the inside of downhole tubulars in oil fields. When crude flow is diminished below acceptable operational requirements, the pipe is sent to a descaling operation to be cleaned, most likely by a method known as rattling. The rattling process generates dust. This research investigated the chemical composition of that aerosol and measured the solubility of pipe scale from three oilfield formations. Using standard in-vitro dissolution experimental equipment and methods, pipe scale is introduced into simulated lung fluid over a two-week period. These samples are analyzed using quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS), known for very low detection limits. Analysis reveals virtually no 226Ra present in the lung fluid exposed to pipe scale. Sample measurements were compared against background measurements using Student??s t test, which revealed that nearly all the samples were statistically insignificant in comparison to the lung fluid blanks. This statistical test proves within a 95% confidence interval that there is no 226Ra present in the lung fluid samples. These results indicate that inhaled NORM pipe scale should be classified as Class S and serve to further confirm the extreme insolubility of petroleum pipe scale. For dose calculations, the S classification means that the lung is the main organ of concern. Radium-226 from petroleum pipe scale does not solubilize in the interstitial lung fluid, and does not, therefore, enter the bloodstream via respiratory pathways. Since there is no removal by dissolution, the 500 day biological half-life implied by the S classification is based solely on the mechanical transport of 226Ra out of the lungs by phagocytosis or the mucociliary escalator.

No description available.

The aim of this doctoral dissertation is to assess the probable impact of ionizing radiation on the public health and the environment (including fauna and flora) in the vicinity of nuclear power engineering objects (in case of the Maišiagala near-surface radioactive waste repository – by evaluating the possible impact on the human health, while in case of the Ignalina NPP cooling basin, Lake Drūkšiai – by evaluating the possible impact on the freshwater ecosystem biota) by applying probabilistic methods as well as to determine whether this activity after assessment of its character and impact on the environment meets the standards valid in the Republic of Lithuania or in the European Union and is permissible at a selected site at present or in the future. In the work two main programs, RESRAD-OFFSITE and ERICA, using scattering of site-specific parameter values and probabilistic (correlation, regressive, sensitivity, etc.) analysis, have been applied. It has been determined that in the environment of the Maišiagala repository after installation of additional protective barriers the annual effective human exposure dose is significantly lower as compared to the limited dose and 95th percentile dose not exceed the exposure of 1 mSv per year regulated in the hygiene standards. The exposure dose rate of standardized organisms of Lake Drūkšiai, the Ignalina NPP cooler, freshwater ecosystem biota due to the INPP discharges and waterway radionuclide migration from a hypothetic... [to full text] / Šios daktaro disertacijos tikslas - įvertinti galimą jonizuojančiosios spinduliuotės poveikį visuomenės sveikatai ir aplinkai (tame tarpe gyvūnijai ir augalijai) branduolinės energetikos objektų aplinkoje (Maišiagalos radioaktyviųjų atliekų saugyklos atveju - vertinant galimą poveikį žmogui, ir IAE aušintuvo Drūkšių ežero atveju - vertinant galimą poveikį gėlavandenės ekosistemos biotai), taikant tikimybinius metodus; nustatyti, ar ši veikla, įvertinus jos pobūdi ir poveikį aplinkai, atitinka Lietuvos Respublikoje arba Europos Sąjungoje galiojančius standartus, yra leistina pasirinktoje vietoje dabartiniu laikotarpiu arba ateityje. Darbe buvo taikomos 2 pagrindinės programos: RESRAD-OFFSITE ir ERICA., naudojant vietines sąlygas atitinkančius parametrų verčių išbarstymą, taikant tikimybinę (koreliacinę, regresinę, jautrio ir kt.) analizę. Nustatyta, kad, įrengus papildomus apsauginius barjerus, Maišiagalos saugyklos aplinkoje metinė efektinė gyventojų apšvitos dozė yra ženkliai mažesnė lyginant su apribotosios dozės dydžiu, 95 procentilė nesiekia higienos normose patvirtintos 1mSv per metus ribinės dozės dydžio. Ignalinos AE aušintuvo Drūkšių ežero gėlavandenės ekosistemos biotos standartizuotųjų organizmų apšvitos dozės galia dėl IAE nuotekų ir radionuklidų sklaidos vandens keliu iš hipotetinio Stabatiškės radioaktyviųjų atliekų kapinyno rodo, kad apšvitos dozės galia dėl antropogeninės kilmės radionuklidų jonizuojančiosios spinduliuotės poveikio neviršija Europos Sąjungoje... [toliau žr. visą tekstą]

Šios daktaro disertacijos tikslas - įvertinti galimą jonizuojančiosios spinduliuotės poveikį visuomenės sveikatai ir aplinkai (tame tarpe gyvūnijai ir augalijai) branduolinės energetikos objektų aplinkoje (Maišiagalos radioaktyviųjų atliekų saugyklos atveju - vertinant galimą poveikį žmogui, ir IAE aušintuvo Drūkšių ežero atveju - vertinant galimą poveikį gėlavandenės ekosistemos biotai), taikant tikimybinius metodus; nustatyti, ar ši veikla, įvertinus jos pobūdi ir poveikį aplinkai, atitinka Lietuvos Respublikoje arba Europos Sąjungoje galiojančius standartus, yra leistina pasirinktoje vietoje dabartiniu laikotarpiu arba ateityje. Darbe buvo taikomos 2 pagrindinės programos: RESRAD-OFFSITE ir ERICA., naudojant vietines sąlygas atitinkančius parametrų verčių išbarstymą, taikant tikimybinę (koreliacinę, regresinę, jautrio ir kt.) analizę. Nustatyta, kad, įrengus papildomus apsauginius barjerus, Maišiagalos saugyklos aplinkoje metinė efektinė gyventojų apšvitos dozė yra ženkliai mažesnė lyginant su apribotosios dozės dydžiu, 95 procentilė nesiekia higienos normose patvirtintos 1mSv per metus ribinės dozės dydžio. Ignalinos AE aušintuvo Drūkšių ežero gėlavandenės ekosistemos biotos standartizuotųjų organizmų apšvitos dozės galia dėl IAE nuotekų ir radionuklidų sklaidos vandens keliu iš hipotetinio Stabatiškės radioaktyviųjų atliekų kapinyno rodo, kad apšvitos dozės galia dėl antropogeninės kilmės radionuklidų jonizuojančiosios spinduliuotės poveikio neviršija Europos Sąjungoje... [toliau žr. visą tekstą] / The aim of this doctoral dissertation is to assess the probable impact of ionizing radiation on the public health and the environment (including fauna and flora) in the vicinity of nuclear power engineering objects (in case of the Maišiagala near-surface radioactive waste repository – by evaluating the possible impact on the human health, while in case of the Ignalina NPP cooling basin, Lake Drūkšiai – by evaluating the possible impact on the freshwater ecosystem biota) by applying probabilistic methods as well as to determine whether this activity after assessment of its character and impact on the environment meets the standards valid in the Republic of Lithuania or in the European Union and is permissible at a selected site at present or in the future. In the work two main programs, RESRAD-OFFSITE and ERICA, using scattering of site-specific parameter values and probabilistic (correlation, regressive, sensitivity, etc.) analysis, have been applied. It has been determined that in the environment of the Maišiagala repository after installation of additional protective barriers the annual effective human exposure dose is significantly lower as compared to the limited dose and 95th percentile dose not exceed the exposure of 1 mSv per year regulated in the hygiene standards. The exposure dose rate of standardized organisms of Lake Drūkšiai, the Ignalina NPP cooler, freshwater ecosystem biota due to the INPP discharges and waterway radionuclide migration from a hypothetic... [to full text]