To see the other types of publications on this topic, follow the link: Effectice dose.
Dissertations / Theses on the topic 'Effectice dose'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Effectice dose.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Li, Zezheng. "Estimating Minimum Effective Dose in Dose Response Studies." Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/pdf/LiZ2009.pdf.
Full text
2
Vu, Hung Thi Hong. "Testing the individual effective dose hypothesis." Connect to this title online, 2009. http://etd.lib.clemson.edu/documents/1247508549/.
Full text
3
Veinot, Kenneth Guy. "An angular dependent neutron effective-dose-equivalent dosimeter." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/17595.
Full text
4
Huang, Yangxin. "Interval estimation of effective doses and optimal designs for quantal response experiments." Thesis, Liverpool John Moores University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313104.
Full text
5
Koyama, Shuji, Takahiko Aoyama, Nobuhiro Oda, and Chiyo Yamauchi-Kawaura. "Radiation dose evaluation in tomosynthesis and C-arm cone-beam CT examinations with an anthropomorphic phantom." American Institute of Physics, 2009. http://hdl.handle.net/2237/14184.
Full text
6
Islam, Mohammad Mafijul. "Dose-Response Analysis for Time-Dependent Efficacy." Bowling Green State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1467295354.
Full text
7
Wang, Yinna. "Efficient Stepwise Procedures for Minimum Effective Dose Under Heteroscedasticity." Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1339037272.
Full text
8
Pritz, Jakub. "Biological Effective Dose (BED) Distribution Matching for Obtaining Brachytherapy Prescription Doses & Dosimetric Optimization for Hybrid Seed Brachytherapy." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3298.
Full textAbstract:
Radioactive seed implant brachytherapy is a common radiotherapy treatment method for prostate cancer. In current clinical practice, a seed consists of a single isotope, such as 125I or 103Pd. A seed containing a mixture of two isotopes has been proposed for prostate cancer treatment. This study investigates a method for defining a prescription dose for new seed compositions based on matching the biological equivalent dose (BED) of a reference plan.
Ten prostate cancer cases previously treated using single isotope seeds (5 using 125I seeds and 5 using 103Pd seeds) were selected for this study. Verification of the method was done by calculating prescription doses for 103Pd and 125I seeds. A prescription dose for a 50/50 hybrid seed was calculated. Number and location of seeds remained invariant within each case. The BED distributions for hybrid and single isotope seed plans were generated and matched to the BED distribution generated off of the optimized plans.
For the 125I isotopes, the dose necessary to cover 90% of the prostate with a BED of 110 Gy is 145 Gy. For the same BED coverage, the dose for 103Pd and 50/50 hybrid seed is 120 Gy and 137 Gy respectively.
A method is introduced for obtaining prescription doses for new brachytherapy sources. The method was verified by obtaining doses for 125I and 103Pd isotopes which match clinical prescription doses. The method developed is robust enough to calculate prescription doses in any region of interest, for any seed type, and for any isotope as long as the BED coverage remains invariant with respect to the treatment plan.
Numerical calculations were performed to derive analytical conversions of total dose to BED for 50/50, 75/25 and 25/75 hybrid seeds. These analytical conversions are faster than the original numerical methods employed allowing for real-time BED optimization for hybrid seeds.
Varying seed distribution was seen not to influence the analytical conversions. It was observed that when total dose remained invariant while individual isotope contributions varied, the value of BED varied. The BED variance was seen to be the smaller at larger BED values (~2% at 100 Gy).
Using the conversions derived in this paper, BED based optimization for hybrid seeds are now performable. However, these conversions should only be used in high dose regions due to high uncertainty in the low regime.
9
Henriksson, Katja. "Strålskydd för nuklearmedicinsk personal som jobbar med Tc-99m: vikten av att använda blyförkläde, sprutskydd och distansverktyg." Thesis, Malmö universitet, Fakulteten för hälsa och samhälle (HS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-25533.
Full textAbstract:
Inom nuklearmedicin exponeras personal dagligen för joniserande strålning. Det kan vara både i form av en öppen strålkälla vid uppdrag av radiofarmaka och vid bildtagning där personalen hjälper och ger stöd till patienten som blivit injicerad. Vid uppdrag av radiofarmaka används strålskydd i form av sprutskydd och distansverktyg medan blyförkläde används vid kontakt med patienter. Dessa skydd är till för att minska skador som kan uppstå vid exponering. Den svenska strålsäkerhetsmyndigheten (SSM) har föreskrivit dosgränser som inte får överskridas för att minska risken för skador. Teknetium-99m (99mTc) är den vanligaste radionukliden inom den nuklearmedicinska verksamheten. Syftet med denna studie var att kartlägga strålningsexponeringen för personal som jobbar med 99mTc och på så sätt visa behovet av olika typer av strålskydd för att reducera stråldosen. I denna studie utfördes fingerdosmätningar vid uppdrag av 99mTc med hjälp av termoluminiscenta dosimetrar som placerades på de tre mest utsatta fingrarna, digitus I-III, bilateralt. Mätningarna genomfördes vid uppdrag utan strålskydd, med en pincett och med fullt strålskydd (sprutskydd samt två pincetter). Studien innefattar även stråldosmätningar med och utan blyförkläde för myokardscintigrafi, skelettscintigrafi och lungscintigrafi. Dessa mätningar utfördes med en direktavläsande personal electronic dosimeter (PED) där den effektiva dosen registrerades. Resultaten för fingerdosmätningarna visar en signifikant skillnad i stråldos beroende på om och vilket strålskydd som används. Högst dos fick de som drog upp helt utan strålskydd och vänster långfinger fick den högsta ekvivalenta dosen. För stråldosmätningarna med och utan blyförkläde utfördes ett Mann-Whitney U-test som visade ett p-värde på <0,05 vilket tyder på att det finns en statistisk signifikant skillnad. Högst effektiv dos uppmättes vid lungscintigrafi för personal som inte använde blyförkläde.Personnel working with radiopharmaceuticals in the nuclear medicine department are exposed to radiation on the daily basis. The source of radiation can both be open as in the withdrawal procedure and external as when the patient has been injected and ready for imaging. There are different types of radiation protection depending on which task that is performed. Syringe shielding and distance tools are used during the withdrawal and lead aprons are used when positioning the patient under the camera. The Swedish radiation safety authority (SSM) prescribe dose limits to reduce any risk of injury connected to radiation. These limits must not be exceeded. Technetium-99m (99mTc) is the most common radiopharmaceutical in the nuclear medicine department. The purpose of this study was to study the radiation exposure to personnel working with 99mTc and evaluate the need for radiation protection to reduce the radiation dose. This study includes measurement of the equivalent dose to the three most exposed fingers, digitus I-III bilateral, during the withdrawal of 99mTc. Thermoluminiscent dosimeters was used to detect radiation and was placed on top of the finger. The measurements were performed without radiation shielding, with only one tweezer as distance tool and with full radiation shielding (syringe shielding and two tweezers as distance tools). It also includes measurement of the effective dose during myocardial scintigraphy, bone scan and lung scintigraphy with or without lead apron. For these measurements a personal electronic dosimeter was used to detect radiation. The result of the finger doses showed a significant difference in radiation dose depending on which protection was used. The highest dose was recovered from not using any protection at all and the highest equivalent dose was obtained by left middle finger. For the measurement regarding the effective dose with or without lead apron a Mann-Whitney U-test was performed and showed a p-value of <0,05 which indicates a statistical significant difference. The highest effective dose was recovered from lung scintigraphy when the personnel was not wearing a lead apron.
10
Long, D., H. Friedrich-Nel, L. Goedhals, and G. Joubert. "High dose-rate brachytherapy in the radical treatment of cervical cancer. An analysis of dose effectiveness and incidence of late radiation complications." Journal for New Generation Sciences, Vol 9, Issue 1: Central University of Technology, Free State, Bloemfontein, 2011. http://hdl.handle.net/11462/580.
Full textAbstract:
Published ArticleWorldwide, uterine cervical cancer is one of the most frequently occurring cancers in women, with more than 80% of these cases occurring in developing countries. The South African screening policy and screening program, implemented in 2001, attempt to reduce this incidence of cervical cancer in South Africa. It is essential to treat these women with the best modalities available. This retrospective study focused specifically on the curative potential of radiotherapy administered to patients at the Oncology Department, Bloemfontein, since a new modality of high dose-rate intracavitary brachytherapy was implemented in 1994. Late radiation complications were also investigated.
11
Hann, Robert Mark. "Estimation of the median effective dose in quantal response biological assay." Thesis, Liverpool John Moores University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299065.
Full text
12
Silva, Paula Perrucho Nou. "Análise dos níveis de radiação nas dependências dos Aceleradores Cíclotron do IPEN." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-07112012-073100/.
Full textAbstract:
O objetivo principal deste estudo foi analisar, na Gerência de Aceleradores Cíclotron do IPEN, o controle das doses de radiação ionizante e sua distribuição, comparando seus valores com as exigências regulamentares. A análise do controle das taxas de dose por meio do monitoramento de área foi realizada a partir de dados obtidos durante as produções de Flúor-18 no período de janeiro de 2010 a dezembro de 2011, totalizando 1011 medidas em cada ponto monitorado. A análise das doses provenientes de exposições ocupacionais foi realizada por meio de consulta aos históricos de dose individual. Durante os anos de 2007 a 2011 foram analisados os registros individuais das doses efetivas, totalizando 91 registros e de 2009 a 2011 foram analisados os registros de dose equivalente (nas mãos), totalizando 49 registros. Os indivíduos ocupacionalmente expostos envolvidos no estudo foram classificados, de acordo com a tarefa, em três grupos: alvos, radioproteção e operação e manutenção. Os resultados obtidos dos níveis de exposição ocupacional da radiação foram analisados e comparados com os limites estabelecidos pela autoridade regulatória nacional e com as recomendações internacionais. Com base nos resultados registrados do monitoramento de área e das doses recebidas, os procedimentos de radioproteção aplicados na instalação durante o período estudado foram averiguados e sugestões de melhorias foram dadas sob o ponto de vista da proteção radiológica.The main purpose of this study was to analyze, at the Gerência de Aceleradores Cíclotron (Management of Cyclotron Accelerators) at IPEN, the control of ionizing radiation doses and their distribution by comparing their values with regulatory requirements. The analysis of the dose rate for the area monitoring was carried out from the data obtained during the production of Fluorine-18 from January 2010 to December 2011, totalizing 1011 measurements at each monitored spot. The doses analysis was performed through consultation of the individual dose records. During the years 2007 to 2011 the records of individual effective doses were analyzed, adding up to 91 records; from 2009 to 2011 the records of equivalent dose (hands) were analyzed, totalizing 49 records. The occupationally exposed individuals involved in the study were classified in three groups according to their task: targets, radioprotection and operation and maintenance. The results of occupational exposure levels of radiation were analyzed and compared with values established in national standards and international recommendations. Based on the results of the area monitoring and the doses received and recorded, radiation protection procedures implemented at the facility during the study period were checked and suggestions for improvements were given from the point of view of radiological protection.
13
Reilly, Amanda. "Effective Allocation of Reactive Cholera Vaccines: A One or Two Dose Campaign?" Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:17417579.
Full textAbstract:
Every year for the past five years, over 100,000 cases of cholera have been reported to the World Health Organization (WHO). Though cholera is by no means a new disease, its containment in low-income countries has proved impossible with traditional measures such as WASH interventions. To supplement these far-reaching interventions, the WHO has proposed and begun to amass a reactive vaccine stockpile. As outbreaks are reported, the WHO intends to evaluate them and determine if a reactive vaccination supplement is appropriate. Understanding how to optimally allocate reactive vaccines is essential to the WHO’s evaluation of a country’s need for vaccines. The primary focus of this paper is to determine which conditions are appropriate for one or two dose reactive vaccination campaigns over a variety of parameter values. Though a range of parameter values are examined, the results indicate that the incremental benefit of the second dose is relatively small.Applied Mathematics
14
Toyinbo, Peter A. "On Effective and Efficient Experimental Designs for Neurobehavioral Screening Tests: The Choice of a Testing Time for Estimating the Time of Peak Effects." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000393.
Full text
15
Kicken, Peter Joseph Hubert. "Radiation dosimetry in vascular radiology organ and effective dose to patients and staff /." [Maastricht : Maastricht : Universitaire Pers Maastricht] ; University Library, Maastricht University [Host], 1996. http://arno.unimaas.nl/show.cgi?fid=7390.
Full text
16
Schinwald, Anja. "Toxicology of high aspect ratio nanomaterials : how shape determines the biologically effective dose." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8797.
Full textAbstract:
Nanotechnologies are the fastest growing industry sector ever recorded. The US budget for nanotechnology is predicted to reach the 1 trillion dollar threshold in 2015, meaning that nanotechnologies will indeed be larger than all other technologies combined. High aspect ratio nanomaterials (HARN) become increasingly important in the nanotechnology industries, and show great promise, offering many advantages and improvements to a significant range of products. The main feature of HARN is the ratio of the width of a nanomaterial to its height which can be up to 1000, making the material fibre or platelet- shaped. However, this feature leads to comparison between HARN and other high aspect ratio materials including fibre shaped materials, such as asbestos fibres. Due to the structural similarities between fibrous HARN and asbestos the question arises- do HARN pose the same risk as asbestos? This project aimed to assess the potential of a range of HARN to cause similar pathological effects as asbestos fibres. In order to address this aim a panel of HARN was tested against the fibre pathogenicity paradigm in vivo by examining the pulmonary and pleural responses as well as in vitro to reveal the mechanism of cell/HARN interaction. The first part of the study focused on fibre-shaped HARN, including a panel of distinct length classes of silver nanowires (AgNW) which were injected directly into the pleural space, a target tissue for asbestos related diseases. Injection of high aspect ratio AgNW into the pleural space of mice revealed a length dependent inflammatory response in line with the fibre pathogenicity paradigm which explains fibre pathogenicity. AgNW from 5 μm in length and above led to a significant increase in granulocytes in the pleural space which is similar to that seen after treatment with long amosite asbestos. The use of additional HARN with different compositions allowed us to identify a threshold length for fibre-induced pleural inflammation, which is 5 μm. Frustrated phagocytosis has been stated as an important factor in the initiation of an inflammatory response after fibre exposure. A novel technique, backscatter scanning electron microscopy (BSEM), was used to study frustrated phagocytosis since it provides high-contrast detection of nanowires, allowing clear discrimination between the nanofibres and other cellular features. Using this technique we showed that the onset of inflammation does not correlate with the onset of frustrated phagocytosis, with a fibre length of ≥5 μm and ≥10 μm, respectively, leading to the conclusion that intermediate length fibres fully enclosed within macrophages as well as frustrated phagocytosis are associated with a proinflammatory state in the pleural space. We further showed that fibres compartmentalise in the mesothelial cells at the parietal pleura as well as in inflammatory cells in the pleural space. To investigate the mechanism of the lengthdependent inflammation caused by AgNW, the NALP3 inflammasome activation pathway was studied in vitro, however no clear correlation could be identified. We further aimed to investigate the threshold length of fibre-induced inflammation in the lung and the effect of fibre length on macrophage locomotion in an in vitro macrophage migration assay. Pharyngeal aspiration of AgNW resulted in a length dependent inflammatory response in the lungs with threshold at a fibre length of 14 μm. Shorter fibres including 3, 5 and 10 μm elicited no significant inflammation. This identified threshold length differs from that in the pleural space which may be explained by differences in clearance mechanism of deposited fibres from the airspaces compared to the pleural space. Particle clearance from the lung is partly performed by migration of particle-laden macrophages to the mucociliary escalator. We investigated if uptake of longer fibres leads to restricted mobility and showed that exposure to AgNW in the length of ≥ 5 μm resulted in impaired motility of macrophages in the wound closure assay. The second part of the study focused on HARN in the form of nanoplatelet-shaped particles since nanoplatelets may pose an unusual risk to the lungs and the pleural space because of their aerodynamic properties. We first derived the respirability of graphene nanoplatelets (GP) from the basic principles of the aerodynamic behaviour of plate-shaped particles which allowed us to calculate their aerodynamic diameter. This showed that the nanoplatelets, which were up to 25 μm in diameter, were respirable and so would deposit beyond the ciliated airways following inhalation. We therefore utilized models of pharyngeal aspiration and direct intrapleural installation of GP, as well as an in vitro model, to assess their inflammatory potential. These large but respirable GP were inflammogenic in both the lung and the pleural space at an acute timepoint although they decreased in their inflammatory potential over a 6 weeks period. Oxidation of GP in the lung tissue was investigated in order to identify if GP degraded over the 6 week period in the lung tissue and therefore showed reduced inflammogenicity. Raman spectroscopy was used to measure the oxidation state and revealed that no change occurred over the observed timeframe. The mechanism underlying acute GP inflammation was studied in THP-1 macrophages exposed to GP. These investigations showed that GP exposure led to significant expression of IL-1β, which could be blocked via a number of inhibitors related to the NALP3 inflammasome activation. This study highlights the importance of shape/length of HARN as a driver for in vivo and in vitro inflammogenicity by virtue of their respirable aerodynamic diameter, despite a considerable 2-dimensional size which leads to an inflammatory response when deposited in the distal lungs and the pleural space. The identification of the threshold length for nanofibre-induced pathogenicity in the pleura and the lung has important implications for the understanding of the structure–toxicity relationship for asbestos-induced mesothelioma. It also contributes to risk assessment by offering a template for production of safer synthetic nanofibres by the adoption of a benign-bydesign approach. The results of this work highlight the importance of testing new HARN to protect workers in nanotechnology industries and the public.
17
MENDONÇA, Keyla Mary Cavalheiro. "Avaliação dosimétrica de familiares e ambiente domiciliar de pacientes com hipertireoidismo submetidos à radioiodoterapia ambulatorial." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/20275.
Full textAbstract:
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-08-07T14:15:11Z
No. of bitstreams: 2
license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5)
Tese doutorado Keyla Mendonça.pdf: 1892604 bytes, checksum: 11d46f4a20b26b6f0556122ab34f0316 (MD5)Made available in DSpace on 2017-08-07T14:15:12Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Tese doutorado Keyla Mendonça.pdf: 1892604 bytes, checksum: 11d46f4a20b26b6f0556122ab34f0316 (MD5) Previous issue date: 2016-08-05
CNPQ
A radioiodoterapia (RIT) para hipertireoidismo é feita ambulatorialmente há cerca de 70 anos, com poucas restrições quanto à segurança radiológica dos familiares de convívio domiciliar. Diante disso, o objetivo do estudo foi avaliar o impacto radiológico da RIT para hipertireoidismo por meio de levantamento das exposições no ambiente domiciliar destes pacientes nos primeiros seis dias pós-tratamento, para servir como um parâmetro real na tomada de decisões relacionadas com a conduta terapêutica e estabelecimento de novas recomendações práticas e seguras desta terapia. Dosímetros termoluminescentes TLD-100 foram colocados nos acompanhantes e nos ambientes domiciliares de 25 pacientes hipertireóideos tratados com atividades de 555 MBq (n=9), 740 MBq (n=7) e 1110 MBq (n=9). Além disso, foram verificadas as contaminações superficiais de objetos e materiais desses pacientes. As doses efetivas obtidas por meio dos TLDs-100 foram de 0,9 mSv, 0,6 mSv e 0,2 mSv, para atividades administradas de 555 MBq, 740 MBq e 1110 MBq, respectivamente. Os valores médios de equivalente de dose ambiental dos locais mais frequentados dos pacientes, como quarto, cozinha, banheiro e sala foram de: 2,11; 0,15; 0,20 e 0,44 mSv, respectivamente. A monitoração de objetos e materiais de âmbito domiciliar para cada grupo de atividade 555, 740 e 1110 MBq variaram de valores indetectáveis até próximos a 150 Bq.cm-2. No Brasil, a norma 3.05 da Comissão Nacional de Energia Nuclear estabelece que pacientes tratados com 131I possam realizar terapia com atividades até 1850 MBq, em regime ambulatorial, sem nenhuma restrição de isolamento. Além disso, a norma 3.01da Comissão nacional de energia Nuclear estabelece os limites de dose efetiva para indivíduos do público e acompanhantes/voluntários, como sendo de 1 mSv e 5 mSv por ano, respectivamente. Comparando a população estudada com a norma vigente, apenas duas acompanhantes de pacientes ultrapassaram o limite estabelecido. Pressupõe-se que o contato físico próximo e constante delas aos pacientes, em consequência da exiguidade do espaço domiciliar, resultou nessas doses efetivas. Conclui-se que o tratamento do hipertireoidismo em regime ambulatorial com atividades de até 1.110 MBq, foi realizado de forma segura e forneceu informações úteis sobre a proteção e exposição dos familiares e acompanhantes de pacientes.
The radioiodine therapy (RIT) for hyperthyroidism is done on an outpatient basis for about 70 years, with few restrictions on radiological safety of household living family. Thus, the objective of the study was to evaluate the radiological impact of RIT for hyperthyroidism through survey of exposures in the home environment of these patients in the first six days after treatment, to serve as an actual parameter in making decisions related to the therapeutic approach and establishment of new practices and safe recommendations of this therapy. TLD-100 thermoluminescent dosimeters were placed in the accompanying domestic environments and 25 hyperthyroid patients treated with 555 MBq Activity (n = 9), 740 MBq (n = 7) and 1110 MBq (n = 9). Furthermore, the surface contamination of objects and materials of these patients were checked. The effective doses obtained through the TLDs-100 were 0.9 mSv 0.6 mSv and 0.2 mSv for administered activity of 555 MBq 740 MBq and 1110 MBq, respectively. The average values of ambient dose equivalent of the busiest places of the patients, such as bedroom, kitchen, bathroom and living room were: 2,11; 0.15; 0.20 and 0.44 mSv, respectively. Monitoring objects and home environment of materials for each activity group 555, 740 and 1110 MBq ranged from undetectable to near 150 Bq.cm-2. In Brazil, the standard 3:05 of the National Nuclear Energy Commission established that patients treated with 131I can perform therapy activities up to 1850 MBq, in an outpatient setting, without any isolation restriction. In addition, the standard 3.01da National Nuclear Energy Commission shall establish the effective dose limits for individuals from the public and chaperones / volunteers, as of 1 mSv to 5 mSv per year, respectively. Comparing the study population with the current regulations, only two companions of patients exceeded the limit. It is assumed that the close physical contact and constant them to patients as a result of the paucity of home space, resulted in these effective doses. We conclude that treatment of hyperthyroidism on an outpatient basis with up to 1,110 MBq activities was carried out safely and provided useful information on the protection and exposure of family members and patients companions.
18
Ezzo, Issa. "Determination of the conversion factor for the estimation of effective dose in lungs, urography and cardiac procedures." Thesis, Stockholm University, Medical Radiation Physics (together with KI), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8520.
Full textAbstract:
Patient dose in diagnostic radiology is usually expressed in terms of organ dose and effective dose. The latter is used as a measure of the stochastic risk. Determinations of these doses are obtained by measurements (Thermoluminescent dosemeters) or by calculations (Monte Carlo simulation).
Conversion factors for the calculation of effective dose from dose-area product (DAP) values are commonly used to determine radiation dose in conventional x-ray imaging to realize radiation risks for different investigations, and for different ages. The exposure can easily be estimated by converting the DAP into an effective dose.
The aim of this study is to determine the conversion factor in procedures by computing the ratio between effective dose and DAP for fluoroscopic cardiac procedures in adults and for conventional lung and urography examinations in children.
Thermoluminescent dosemeters (TLD) were placed in an anthropomorphic phantom (Alderson Rando phantom) and child phantom (one year old) in order to measure the organ dose and compute the effective dose. A DAP meter was used to measure dose-area product.
MC calculations of radiation transport in mathematical anthropomorphic phantoms were used to obtain the effective dose for the same conditions with DAP as input data.
The deviation between the measured and calculated data was less than 10 %. The conversion factor for cardiac procedures varies between 0.19 mSvGy-1 cm-2 and 0.18 mSvGy-1 cm-2, for TLD respective MC. For paediatric simulation of a one year old phantom the average conversion factor for urography was 1.34 mSvGy-1 cm-2 and 1,48 mSvGy-1cm-2 for TLD respective MC. This conversion factor will decrease to 1.07 mSvGy-1 cm-2 using the TLD method, if the new ICRP (ICRP Publication 103) weighting factors were used to calculate the effective dose.
For lung investigations, the conversion factor for children was 1.75 mSvGy-1 cm-2 using TLD, while this value was 1.62 mSvGy-1 cm-2 using MC simulation. The conversion value increased to 2.02 mSvGy-1 cm-2 using ICRP’s new recommendation for tissue weighting factors and child phantom.
19
Oehme, Liane. "Einflussgrößen der Nephrotoxizität eines Radiotracers am Beispiel der Radioimmuntherapie mit 188Re-anti-CD66." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1235575020375-20209.
Full textAbstract:
Die Nephrotoxizität ist die wichtigste Nebenwirkung bei Applikation von Radioimmunkonjugaten zur Konditionierung des Knochenmarks bei der Leukämiebehandlung. Die Auswirkungen der Unsicherheiten bei der Dosisbestimmung der Niere, insbesondere durch individuelle Nierenmasse und regionale Aktivitätsunterschiede, wurden untersucht. Die biologische Strahlenwirkung wurde als Biologisch Effektive Dosis unter Berücksichtigung des Zeitverlaufs der Dosisapplikation quantifiziert. Berechnungen wurden neben 188Rhenium auch für andere therapierelevante Radionuklide durchgeführt.
20
Benhalim, M. R. "Impact of acquisition protocol variations on effective dose and risk for CT head examinations." Thesis, University of Salford, 2018. http://usir.salford.ac.uk/46782/.
Full textAbstract:
PURPOSE: To propose a method for estimating the effective lifetime risk of radiation-induced cancer from different brain CT scan protocols in both paediatrics and adults and to develop a prospective method for estimating the number of cancer cases for patients undergoing CT brain scans when using different scanning parameters. MATERIALS AND METHODS: A series of CT dosimetry experiments were conducted at the University of Salford. Both adult and paediatric ATOM phantoms were imaged using standard CT head protocols across a wide range of protocol variations. Dose measurements were made using metal oxide semiconductor field effect transducers (MOSFETs). Effective doses and lifetime attributable cancer risks were calculated from MOSFETs organ and tissue absorbed dose measurements in both phantoms. The method for lifetime cancer risk prospective estimation allowed the production of prospective risk data (Excel spreadsheet). This can predict attributable lifetime cancer risk, before undertaking a CT scan, and is of critical importance in order to predict more accurately the radiation risks from CT. Whilst such a tool has benefits for all patient ages, it would have particularly value for children - due to their increased radio-sensitivity. Using such a tool, dose optimisation can then occur on a more informed basis, by adjusting protocol parameters with a view to minimising organ and eye dose. Together with advanced image quality preserving techniques, like ACTM, the tool would allow for more informed clinical decisions to be taken to balance image quality and radiation dose on a patient by patient basis. RESULTS: The brain, thyroid, thymus, lung, salivary glands, oral mucosa, extrathoracic region and bone marrow all receive more than 0.03 mSv during CT brain scanning. The range in effective dose across a range of CT brain protocols were 0.27 to 1.13 mSv and 0.34 to 1.55 mSv for adult sequential and helical protocols, respectively. For paediatric helical protocols, the effective dose ranged from 0.30 to 2.06 mSv. In addition to scan parameters, differences in risk are also attributed to patient age at the time of scanning and gender. As an example, the lifetime attributable cancer risk for a 30-year-old patient when undertaking either an adult sequential or helical CT brain scan were 8 females and 6 males per 106 and 16 females and 9 males per 106, respectively. By contrast, for the two paediatric helical CT brains protocols the effective risk (using 3 months to 3 years CT protocol) were 71 females and 36 males per 106 at birth and for the 3 years to 5 years protocol this decreases to 69 females and 35 males per 106 when aged 5. Using the risk data, a novel interactive spreadsheet has been developed and is reported within this thesis, which allows the proactive/prospective estimation of radiation risk for CT head examinations. CONCLUSION: Data collected within this thesis has identified that the most dominant factors effecting absorbed dose are tube current, tube rotation time, detector configuration and helical pitch. When these factors increase the absorbed dose to body organs and tissues increases as well. The only effect of gantry angle is in decreasing the dose to the lens of the eye, this quantity does not factor into effective dose estimates due to the nature of the lens tissue. This thesis proposes a novel method to estimate effective lifetime risk of radiation-induced cancer from CT brain examinations in order to compare different brain CT protocols (acquisition parameters). Absorbed dose measurements when considered in relation to the age and gender of the patient can help provide estimations of effective risk, a potentially more useful indicator of the possible effects of radiation exposure from CT head examinations. This risk estimation method can be used to compare different CT brain protocol parameters immediately prior to imaging. Risk should be prospectively taken into account when planning a CT brain examination, especially for young ages and those undergoing serial imaging. Using the prospective risk data (spreadsheet) provided in this thesis can help to estimate the probability of cancer induction from specific CT brain protocols and can be considered by practitioners and manufacturers when developing CT examinations in the future.
21
Pinder, Emma Muriel. "Does GM-CSF restore effective neutrophil function in critically ill patients?" Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3943.
Full textAbstract:
Nosocomial infection is an increasing problem worldwide associated with significant morbidity and mortality in addition to heightened healthcare costs. The problem is even greater on the intensive care unit (ICU) where up to 20 of patients develop a secondary infection during their admission. In an era of increasing antibiotic resistance alternative strategies to prevent nosocomial infection must be sought. The intensive care population are recognised to be at high risk of developing immune dysfunction during their critical illness and this has been shown to be associated with an increased risk of the development of ICU acquired infection (ICUAI). The neutrophil, in particular, is key in terms of the host response to bacterial and fungal infections and impairments in neutrophil function have been demonstrated in critically ill patients. Granulocyte-macrophage colony-stimulating factor has been shown to improve the phagocytic function of impaired neutrophils ex-vivo and has previously been demonstrated to restore immune competent levels of monocyte HLA-DR expression in critically ill patients. If GM-CSF were demonstrated to restore neutrophil phagocytic function in critically ill patients in whom its known to be impaired it may have a role in preventing the development of ICUAI. Our initial study sought to validate neutrophil CD88 expression as a surrogate marker for phagocytic function. The dose finding study which followed aimed to determine the optimum dose and duration of GM-CSF to be carried forward to a randomised controlled trial. Finally, the randomised controlled trial sought to investigate the hypothesis that GM-CSF could restore effective neutrophil function in critically ill patients. While no significant difference was seen in our primary endpoint of neutrophil phagocytic capacity, on day 2 following administration of GM-CSF, we believe a small but true biological effect was observed suggesting further study is warranted to investigate whether GM-CSF could reduce the risk of ICUAI.
22
Costa, Lucas José Pereira da. "Estudo da exalação de radônio em placas e tijolos de fosfogesso de diferentes procedências." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-03042012-135433/.
Full textAbstract:
O fosfogesso é um resíduo da indústria de fertilizantes fosfatados que concentra radionuclídeos naturais. Neste trabalho foi estudada a taxa de exalação de 222Rn em placas e tijolos de fosfogesso, visando sua utilização na construção de residências. Para tanto, foram determinadas a taxa de exalação de 222Rn por meio da técnica da câmara de acumulação com detectores sólidos de traços nucleares (SSNTD) inseridos em uma câmara de difusão e a dose efetiva para um indivíduo habitando uma residência construída com esses materiais. A título de comparação foi também determinada a taxa de exalação teórica, por meio do modelo proposto pela UNSCEAR, a partir da concentração de 226Ra nas placas e tijolos de fosfogesso. A contribuição do revestimento na superfície dos materiais para a diminuição da taxa de exalação de radônio foi também avaliada. Foram estudados placas e tijolos fabricados com fosfogesso das empresas Bunge Fertilizantes, Ultrafertil e Fosfertil e tijolos fabricados com gesso comum. Os valores médios obtidos foram 0,19 0,06 Bq m-2 h-1, 1,3 0,3 Bq m-2 h-1 e 0,41 0,07 Bq m-2 h-1 para as placas fabricadas com fosfogesso proveniente das empresas Bunge, Ultrafertil e Fosfertil, respectivamente. Já para os tijolos de fosfogesso, os valores foram 0,11 0,01 Bq m-2 h-1, 1,2 0,6 Bq m-2 h-1, 0,47 0,15 Bq m-2 h-1, para o fosfogesso da Bunge, Ultrafertil e Fosfertil. O tijolo fabricado com gesso comum apresentou valor médio de 0,18 0,08 Bq m-2 h-1. As doses efetivas anuais para um indivíduo habitando uma residência construída como os tijolos ou placas de fosfogesso de qualquer uma das procedências ficaram abaixo do limite de dose efetiva para indivíduos do público de 1 mSva-1 estabelecido pela Comissão Internacional de Proteção Radiológica.Phosphogypsum is a waste of the fertilizer industry that concentrates radionuclides. In this work, the 222Rn exhalation rate from phosphogypsum paltes and blocks from different origins used at dwellings construction was studied. The 222Rn exhalation rate was determined through the accumulation chamber technique with solid state nuclear track detectors (SSNTD). The effective dose for an individual living in a residence built with phosphogypsum based materials was evaluated. It also was calculated the 222Rn exhalation rate through the UNSCEAR model, from the 226Ra concentration in the materials, in order to compare the experimental results. It was evaluated the contribution of building component (paint) to the reduction of 222Rn exhalation rate. The plates and blocks were manufactured with phosphogypsum from Bunge Fertilizantes, Ultrafertil and Fosfertil. Blocks manufactured with ordinary gypsum was also evaluated. The average results obtained were 0.19 ± 0.06 Bq m-2 h-1, 1.3 ± 0.3 Bq m-2 h-1 and 0.41 ± 0.07 Bq m-2 h-1for plates manufactured with phosphogypsum from Bunge Fertilizer, Ultrafertil and Fosfertil, respectively. For the phosphogypsum blocks the values were 0.11 ± 0.01 Bq m-2 h-1, 1.2 ± 0.6 Bq m-2 h-1, 0.47 ± 0.15 Bq m-2 h-1, for Bunge, Ultrafertil and Fosfertil. The blocks manufactured with ordinary gypsum presented average value of 0.18 ± 0.08 Bq m-2 h-1. All phosphogypsum plates and blocks evaluated in this study presented effective dose for radon inhalation lower than the recommended value of 1mSv y1, the annual effective dose limit for public exposure by International Commission on Radiological Protection.
23
Adamus-Górka, Magdalena. "Improved dose response modeling for normal tissue damage and therapy optimization." Doctoral thesis, Stockholm University, Medical Radiation Physics (together with KI), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-7433.
Full textAbstract:
The present thesis is focused on the development and application of dose response models for radiation therapy. Radiobiological models of tissue response to radiation are an integral part of the radiotherapeutic process and a powerful tool to optimize tumor control and minimize damage to healthy tissues for use in clinical trials. Ideally, the models could work as a historical control arm of a clinical trial eliminating the need to randomize patents to suboptimal therapies. In the thesis overview part, some of the basic properties of the dose response relation are reviewed and the most common radiobiological dose-response models are compared with regard to their ability to describe experimental dose response data for rat spinal cord using the maximum likelihood method. For vascular damage the relative seriality model was clearly superior to the other models, whereas for white matter necrosis all models were quite good except possibly the inverse tumor and critical element models. The radiation sensitivity, seriality and steepness of the dose-response relation of the spinal cord is found to vary considerably along its length. The cervical region is more radiation sensitive, more parallel, expressing much steeper dose-response relation and more volume dependent probability of inducing radiation myelitis than the thoracic part. The higher number of functional subunits (FSUs) consistent with a higher amount of white matter close to the brain may be responsible for these phenomena. With strongly heterogeneous dose delivery and due to the random location of FSUs, the effective size of the FSU and the mean dose deposited in it are of key importance and the radiation sensitivity distribution of the FSU may be an even better descriptor for the response of the organ. An individual optimization of a radiation treatment has the potential to increase the therapeutic window and improve cure for a subgroup of patients.
24
Antonio, Graziella Colato. "Avaliação do efeito dos pre-tratamentos de desidratação osmotica e secagem HTST na obtenção desnacks de batata doce (Ipomoea Batatas Lam)." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/322492.
Full textAbstract:
Orientador: Fernanda Elizabeth Xidieh MurrTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-08T04:46:19Z (GMT). No. of bitstreams: 1 Antonio_GraziellaColato_D.pdf: 42506769 bytes, checksum: 5f92bccd2127615161debdd246e72ec7 (MD5) Previous issue date: 2006
Doutorado
Doutor em Engenharia de Alimentos
25
Campos, Carlos Austerlitz. "Choice of personnel dosimeter location to assess the effective dose equivalent for various photon irradiations." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/12916.
Full text
26
Marina, Zdraveska Kochovska. "Effective dose estimation and risk assessment in patients treated with iodine 131I using Monte Carlo simulation." Phd thesis, Univerzitet u Novom Sadu, Asocijacija centara za interdisciplinarne i multidisciplinarne studije i istraživanja, 2014. http://www.cris.uns.ac.rs/record.jsf?recordId=90158&source=NDLTD&language=en.
Full textAbstract:
The most frequently used radiopharmaceutical for treatment of thyroid diseases such as Thyroid Cancer and Hyperthyroidism is radioactive iodine 131I. It has a very high success rate in treatment of patients with thyroid diseases and also it has been proven to be safe and relatively inexpensive treatment modality. Whenever radiation is used in the treatment of the benign or cancer diseases dosimetry is essential. The main aim of this study is to perform external measurements of dose rate after administered activity and to simulate dosimetry of internal organs and risk assessment using MCNP 4b code, either for thyroid cancer and Hyperthyroid patients. To search safety optimization in this kind of therapy, it was recognized the necessity of more accurate knowledge of dose levels received by stomach and other organs. Of great importance is to know the effective dose that will be reached in gastric and other surrounding organs such as liver, lung, bladder etc. Additional aim was to provide information to be used in the improvement of radiation therapy, radiation safety practices and improvement of the fundamentals of radiation protection as defined by ICRP: justification, optimization and application of dose limits. The significance of this research is that the doses to internal organs can be determined and it worth to mention that such internal dosimetry calculation has been performed rare in the field of nuclear medicine. In accordance with the calculations carried out during this study and reference available in the literature that the therapy with radioiodine will be improved at the Institute of pathophysiology and nuclear medicine. Designed quality programs will be useful also for regulatory and accreditation bodies in the process of accreditation and radiation protection strategy. This work is divided into interconnected chapters. Chapter 2 to 4 contains the literature review and theoretical background of the study. Chapter 3 covers material and methods and aspect of Monte Carlo transport code focused on MCNP 4b code. Chapter 4 provides the results and discussion of the findings. Conclusions and recommendations are discussed in Chapter 5. Chapter 6 contains references used in this work.Cilj terapije sa radiaoktivnim jodom 131I kod pacijenata koji boluju od nekih tipova tiroidnih carcinoma i hipertiroidizma je isporuka doze i apsorpcija doze u tiroidnoj žlezdi. Terapija sa radioaktivnim jodom sprovodi se u obliku rastvora Na131I (natrijum jodida) u tečnoj formi ili aplicira se u formi kapsule. Efektivna doza je rezultat apsorbovane doze u tiroidnom tkivu, ali i ostali unutrašnji organi prime izvesnu dozu. Kapsule koje sadrže natrijum jodid ostaju u stomaku oko 15 minuta pre nego što započne apsorpcija, vreme dovoljno dugo za rizično izlaganje. Ova činjenica je jedan od ciljeva doktorske teze, odrediti efektivnu dozu u stomaku i nekoliko unutrašnjih okolnih organa modelovanje transporta i interakcije gama zračenja i beta čestica emitovanih iz radionuklida 131I je korišćen Monte Karlo kod (MCNP4b). Radiojod je modelovan kao tačkasti izvor na dnu stomaka. Proračunavana je apsorbovana energija po jedinici transformacije u stomaku i okolnim organima. Ekvivalentna doza u tim organima je izračunata da bi se odredila efektivna doza primenom odgovarajućih težinskih faktora. Dobijeni rezultati imaju značaja za zaštitu od zračenja, ali su važni i za ustanovljavanje novih kalibracionih procedura kao deo sigurnosne kontrole i kontrole kvaliteta u proizvodnji i kontroli radiofarmaceutika kao i procedure administriranja radiofarmaceutika i primene bolnčikih puteva. Smatramo da če rezultati ovog istraživanja poboljšati bezbednosnu kulturu u našem sistemu zdravstvene zaštite kao i u državnim organima koji kreiraju i donose regulative.
27
Jones, Paul. "WHAT DOES AN EFFECTIVE REENTRY PROGRAM LOOK LIKE AT A UNIVERSITY CAMPUS?" CSUSB ScholarWorks, 2018. https://scholarworks.lib.csusb.edu/etd/724.
Full textAbstract:
In 2016, University X was awarded a grant to pilot Project Rebound. Project Rebound assist people who are formerly incarcerated navigate the admissions process and graduate from University X with bachelors or master’s degrees. The purpose of this research is to investigate the difficulty that the formerly incarcerated face when assimilating into a new environment far removed from the confines of prison. The current study will answer the questions: what does an effective reentry program look like at University X, and what interventions are most correlated with success? University X’s Project Rebound uses risk assessment instruments and focuses on behavioral outcomes. Using self-administered anonymous surveys, we will identify which interventions or programs are needed to develop a successful college reentry program for formerly incarcerated individuals. Our students require multiple services, which suggests a need for collaboration across other campus programs and county agencies.
28
Peters, Nazlea Behardien. "Determination of effective dose and entrance skin dose from dose area product values for barium studies in adult patients at a large tertiary hospital in the Western Cape." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2627.
Full textAbstract:
Thesis (MSc (Radiography))--Cape Peninsula University of Technology, 2018.Background and objectives The issue of patient doses received during fluoroscopy procedures, raised concerns for the researcher, as there may have been probable past skin injuries or deterministic injuries that may not have been documented. Amongst the radiology staff, there was very little understanding of what the actual dose area product (DAP) value means in real terms of effective dose and entrance skin dose. The aims of the study were to: i) Measure the radiation doses received by the patient and determine a simple means of defining the DAP value to the radiographer in terms of the dose received by the patient. ii) Determine the effective dose, entrance skin dose and the relationship with the DAP value to assist with developing a conversion co-efficient for dose indicators. Method Direct radiation dose measurements can be obtained through DAP meters attached to the diagnostic equipment, but the DAP value is not an direct indication of the effective dose received by the patient. The DAP values captured from the DICOM header information for barium fluoroscopic procedures at a large tertiary was analysed and Diagnostic Reference levels (DRL) were determined for barium swallow, meal and enema procedures. The effective and skin doses were calculated by means of the Monte Carlo program. The results were compared to published values. The relationship between the entrance skin dose and the DAP value was determined and conversion factors were calculated. Results Correlation between the DAP and entrance skin dose and comparative 75th percentile threshold values were determined for barium swallow (BaS), barium meal (BaM) and barium enema (BaE) procedures. Effective to DAP conversation factors for BaS, BaM and BaE are 0.19, 0.26 and 0.60 respectively and 0.15, 0.11 and 0.14 for entrance skin to DAP. Conclusion The the research showed the relationship between the effective dose, entrance skin dose and DAP value and a simple, practical and applicable explanation of the DAP value by means of conversion factors.
29
Yum, Man-Yu. "Statistical methods to estimate the relative contribution of individual effective dose and stochastic models in toxicology." [Ames, Iowa : Iowa State University], 2010. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3403846.
Full text
30
Oehme, Liane. "Einflussgrößen der Nephrotoxizität eines Radiotracers am Beispiel der Radioimmuntherapie mit 188Re-anti-CD66." Doctoral thesis, Technische Universität Dresden, 2008. https://tud.qucosa.de/id/qucosa%3A23918.
Full textAbstract:
Die Nephrotoxizität ist die wichtigste Nebenwirkung bei Applikation von Radioimmunkonjugaten zur Konditionierung des Knochenmarks bei der Leukämiebehandlung. Die Auswirkungen der Unsicherheiten bei der Dosisbestimmung der Niere, insbesondere durch individuelle Nierenmasse und regionale Aktivitätsunterschiede, wurden untersucht. Die biologische Strahlenwirkung wurde als Biologisch Effektive Dosis unter Berücksichtigung des Zeitverlaufs der Dosisapplikation quantifiziert. Berechnungen wurden neben 188Rhenium auch für andere therapierelevante Radionuklide durchgeführt.
31
Manninen, A. L. (Anna-Leena). "Clinical applications of radiophotoluminescence (RPL) dosimetry in evaluation of patient radiation exposure in radiology:determination of absorbed and effective dose." Doctoral thesis, Oulun yliopisto, 2014. http://urn.fi/urn:isbn:9789526206240.
Full textAbstract:
Abstract Computed tomography (CT) and interventional procedures cause relatively high patient doses compared with other imaging modalities in radiology. The optimization of the imaging equipment and procedures is important and necessary due to the known risks caused by ionization radiation. The different irradiation geometries and dose units between imaging techniques complicate the comparison of patients’ radiation exposure. Absorbed doses (D) of organs predict the tissue reactions of the procedures, while effective dose (E) is a useful means of comparing the stochastic effects of the different imaging procedures. A and E can be estimated from dosimetric measurements in a phantom. In vivo measurements are used during a radiological examination. In the present thesis, various properties of radiophotoluminescence dosimeters (RPLD) were investigated to verify the applicability of RPL dosimetry in radiology. The absorbed dose was determined in vaginal fornix of seven pregnant women, in the area near the head of the fetus during prophylactic catheterization before uterine artery embolization (UAE). The evaluation of the radiation exposure of digital subtraction angiography (DSA) and computed tomography angiography (CTA) was performed using an anthropomorphic phantom. Absorbed doses of organs and effective dose were determined for a typical four-vessel angiography of the cerebral area, including intracranial vessels, and for the cervicocerebral area, including both cervical and intracranial vessels. RPLD shows excellent dose linearity and minimal fading. The low dose detection threshold was determined to be 20 µGy with a coefficient of variation (CV) of 12.2%. The methodology is independent of photon energy in the energy range used in radiology. For seven patients studied, the mean value of D in vaginal fornix was 11.2 mGy (range 2.2–28.7) being low dose study when pulsed fluoroscopy with an optimized protocol is used without angiography exposures. In the assessment of cerebral vessels, the effective dose for CTA was approximately one-fifth of the dose compared with DSA. The dose for cervicocerebral vessels CTA was approximately one third higher compared with DSA. Conversion factors from the DAP and the DLP to the effective dose were calculated for the specific angiographic protocols. RPL dosimetry shows sufficient reliability in measuring radiation doses in radiologyTiivistelmä Tietokonetomografiakuvauksissa ja toimenpideradiologisissa tutkimuksissa potilaan säteilyaltistus on suhteellisesti korkeampi verrattuna muihin radiologisiin kuvausmenetelmiin. Kuvauslaitteiden erilaiset kuvausgeometriat ja annosyksiköt hankaloittavat potilaan säteilyaltistuksen vertailua eri tutkimusmenetelmien välillä. Kudokseen absorboituneen annoksen (D) avulla arvioidaan ionisoivan säteilyn suoraa haittavaikutusta kudokselle, kun taas efektiivisen annoksen (E) määrittämisellä arvioidaan säteilyn satunnaista haittaa. D ja E voidaan mitata annosmittarilla käyttäen potilasvastinetta. In vivo mittauksella saadaan annostietoa tutkimuksen aikana suoraan potilaasta. Radiofotoluminesenssiannosmittarin (RPLD) soveltuvuus radiologisiin annosmittauksiin varmistettiin tutkimalla mittarin eri fysikaalisia ominaisuuksia. RPLD:a käytettiin intravaginaalisen annoksen mittauksessa seitsemällä raskaana olevalla naisella. Potilaille tehtiin massiivisen verenvuodon ehkäisemiseksi kohdun valtimosuonten katetrointi läpivalaisuohjattuna ennen kohtuvaltimoiden tukkimishoitoa (UAE). Mittaustulokset antavat tietoa kudokseen absorboituneesta annoksesta lähellä syntymätöntä lasta. Tietokonetomografia-angiografia (TTA) ja digitaalinen subtraktioangiografia (DSA) tutkimusten annosmittaukset tehtiin potilasvastineessa käyttäen RPLD:a. Elinannoksista laskettiin efektiivinen annos aivovaltimoiden ja aivokaulavaltimoiden angiografiatutkimuksille. RPL -annosmittausmenetelmän havaittiin olevan lineaarinen ja annoksen häviäminen mittarista on vähäistä. Matalan annoksen mittausraja oli 20 µGy 12.2% toistettavuudella. RPLD on riippumaton säteilyenergiasta radiologiassa käytettävällä energia-alueella. Seitsemän potilaan keskimääräinen absorboitunut annos oli 11.2 mGy (vaihteluväli 2.2–28.7 mGy) emättimen pohjukasta mitattuna. Annostaso osoittaa, että katetrointitoimenpide on matala-annostutkimus, kun toimenpide tehdään läpivalaisuohjauksessa, eikä angiografisia kuvia käytetä. Aivovaltimoiden TTA:n efektiivinen annos oli viidesosa DSA menetelmän annoksesta. Aivokaulavaltimoiden TTA:n efektiivinen annos oli arviolta 35% korkeampi kuin DSA menetelmän annos. Konversiokertoimet DAP ja DLP yksiköistä efektiivisen annoksen laskemiseksi määritettiin tutkimuksessa käytetyille kuvausohjelmille. RPL -menetelmä osoitti riittävää luotettavuutta radiologisten säteilyannosten mittauksessa
32
Wang, Gang. "What role does leaders' emotional labor play in effective leadership? An empirical examination." Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/1275.
Full textAbstract:
An increasing stream of research has shown that leaders' emotions have substantial impact on followers' attitudes and performance. However, this line of research has not explored the psychological process leaders use to generate and express their emotions. This is an important gap in the leadership literature because theoretical and empirical work suggests that leaders do manage their feelings and / or expressions of emotions in leader-follower interactions. Therefore, to fill this critical gap, this dissertation examined the role of leaders' emotional labor on followers' attitudes and performance and on leaders' attitudes and well-being.
A longitudinal survey design was employed to test study hypotheses. Data were collected from supervisors and their direct reports in three business organizations in the Midwest. Results show that leaders' surface acting was significantly negatively associated with followers' transformational leadership perceptions, which were positively related to follower job satisfaction, organizational identification, task performance, and organizational citizenship behavior directed toward the organization (OCB-O). Leaders' deep acting and display of genuine emotions were positively related to followers' emotional engagement, which was positively related to job satisfaction, organizational identification, and OCB-O. In addition, the mean level of leaders' expressed positive emotions moderated the relationship between leaders' display of genuine emotions and followers' positive emotional reactions, such that leaders' display of genuine emotions had the most positive effect when followers perceived that the mean level of leaders' expressed emotions was highly positive. Consistent with my arguments, transformational leadership and positive emotional reactions were positively related to emotional engagement, whereas negative emotional reactions were negatively related to emotional engagement. Positive emotional reactions were positively correlated with job satisfaction, organizational identification, organizational citizenship behavior directed toward other individuals (OCB-I), and OCBO. Unlike positive emotional reactions, negative emotional reactions had negative relationships with the above outcome variables. Contrary to my expectations, leaders' surface acting was negatively associated with leaders' emotional exhaustion and leaders' emotional labor was not significantly associated with leaders' job satisfaction. Additional analyses revealed several unexpected but important findings. Theoretical contributions, managerial implications, limitations of the study, and suggestions for future research are discussed.
33
Oliveira, Aline Sebastiane Gonçales Ramos de. "Radioatividade natural, elementos maiores e traços determinados em produtos nacionais derivados da Nicotiana tabacum L." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-13122017-105430/.
Full textAbstract:
O consumo de tabaco é uma das principais causas de doenças e morte prematuras no mundo; é a segunda droga mais consumida entre os adolescentes brasileiros, sendo considerado uma importante porta de entrada para o uso de drogas ilícitas. O Brasil é o segundo produtor mundial de tabaco e desde de 1993 destaca-se como o maior exportador. Os radionuclídeos naturais das séries do 232Th e 238U são encontrados no tabaco em baixas concentrações absorvidos diretamente do solo ou por deposição foliar. No ato de fumar ocorre a transferência desses radionuclídeos através da queima do tabaco para os tecidos e órgãos humanos podendo gerar lesões cancerígenas, sendo o mais relevante o câncer de pulmão. Existem poucos dados sobre a caracterização radiológica e elementar dos derivados do tabaco brasileiros, o que torna relevante o presente estudo que teve como objetivos a determinação da radioatividade natural e da concentração de elementos maiores e traços em derivados de tabaco produzidos e comercializados no Brasil. As técnicas analíticas empregadas foram alfa e beta total após separação radioquímica para os radionuclídeos 226Ra, 228Ra e 210Pb com determinação em detector proporcional de fluxo gasoso e baixa radiação de fundo, espectrometria alfa após separação radioquímica para o radionuclídeo 210Po, análise por ativação com nêutrons instrumental (INAA) e fluorescência por dispersão de raios X (EDXRF) para determinação de 238U, 232Th, elementos maiores e traços. Foram analisados produtos derivados da Nicotina tabacum L. de diferentes marcas adquiridas em tabacarias: cigarro não aromatizados, cigarro aromatizado, charuto, rapé, cigarro de palha e fumo de corda. Pela técnica de INAA foi possível determinar a concentração de 19 elementos e pela técnica de EDXRF de 31 elementos o que possibilitou uma ampla caracterização multielementar e as técnicas analíticas empregadas se mostraram complementares. Os elementos que apresentaram maiores valores de concentração foram o Ca e o K entre todas as amostras amostragem e entre todos os radionuclídeos naturais determinados o 228Ra apresentou maiores valores de concentração de atividade. A partir da concentração de atividade determinada foram calculadas a dose anual estimada e a dose anual efetiva para os radionuclídeos 210Pb e 210Po, levando-se em consideração um consumo anual de 3,65 kg de tabaco por ano. A dose anual efetiva variou de 69,5 μSv ano-1 à 121 μSv ano-1. Os produtos que apresentaram maiores valores de concentração e consequentemente maiores valores de dose anual efetiva, para a maioria dos radionuclídeos analisados, foram os cigarros de palha e fumos de corda.Tobacco use is one of the leading causes of premature illness and death in the world; is the second most consumed drug among Brazilian adolescents, being considered an important gateway to the use of illicit drugs. Brazil is the second largest tobacco producer in the world and since 1993 it has been the largest exporter. The natural radionuclides from the 232Th and 238U series are found in tobacco at low concentrations absorbed directly from the soil or by foliar deposition. In the act of smoking occurs the transference of these radionuclides through the burning of the tobacco to the human tissues and organs and they can generate carcinogenic lesions, being the lung cancer the most relevant. There are few data on the elemental and radiological characterization of Brazilian tobacco products, which makes relevant the present study that had as objectives the determination of the natural radioactivity and the concentration of major and trace elements in tobacco products produced and marketed in Brazil. The analytical techniques employed were gross alpha and beta, after radiochemical separation for the radionuclides 226Ra, 228Ra and 210Pb with determination in a gaseous flow proportional detector of low background radiation, alpha spectrometry after radiochemical separation for the radionuclide 210Po, instrumental neutron activation analysis (INAA) and X-ray scattering fluorescence (EDXRF) for determination of 238U, 232Th, major and trace elements. Nicotine tabacum L. products from different brands acquired in cigar stores were analyzed: non-flavored cigarettes, flavored cigarettes, cigar, snuff, straw cigarettes and rope smoke. Using the INAA technique, it was possible to determine the concentration of 19 elements and with the EDXRF technique 31 elements, which enabled a wide multielementar characterization; the analytical techniques employed were complementary. The elements that presented the highest concentration values were Ca and K among all the samples and among all the natural radionuclides determined the 228Ra presented higher values of activity concentration. The estimated annual dose and annual effective dose for the 210Pb and 210Po radionuclides were calculated from the determined activity concentration, taking into account an annual consumption of 3.65 kg of tobacco per year. The effective annual dose ranged from 69.5 μSv y-1 to 121 μSv y-1. The products with the highest concentration values and hence the highest annual effective dose for the majority of the radionuclides analyzed were straw cigarettes and rope smoke.
34
Salas, Daniela. "Does a participatory sharing and learning approach make an effective HIV provider training program?" restricted, 2007. http://etd.gsu.edu/theses/available/etd-07172007-161836/.
Full textAbstract:
Thesis (M.P.H.)--Georgia State University, 2007.Title from file title page. Michael Eriksen, committee chair; Betty Apt, Marshall Kreuter, committee members. Electronic text (121 p. : ill. (some col.), col. maps)) : digital, PDF file. Description based on contents viewed Oct. 25, 2007. Includes bibliographical references (p. 109-115).
35
AQBI, HUSSEIN F. "Preconditioning of the tumor microenvironment by means of low dose chemotherapies for an effective immunotherapy of breast cancer." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/6025.
Full textAbstract:
Breast cancer mortality is mainly due to distant recurrence of the disease arising from dormant tumor cells established by cancer therapies. Patients who initially respond to cancer therapies often succumb to distant recurrence of the disease. It is not clear why people with the same type of breast cancer respond to treatments differently; some escape from dormancy and relapse earlier than others. In addition, some tumor clones respond to immunotherapy while others do not. We investigated how autophagy plays a role in accelerating or delaying recurrence of neu overexpressing mouse mammary carcinoma (MMC) following adriamycin (ADR) treatment, and in affecting response to immunotherapy. We explored two strategies: 1) transient blockade of autophagy with chloroquine (CQ), which blocks fusion of autophagosomes and lysosomes during ADR treatment, and 2) permanent inhibition of autophagy by a stable knockdown of ATG5 (ATG5KD), which inhibits the formation of autophagosomes in MMC during and after ADR treatment. We found that while CQ prolonged tumor dormancy, but that stable knockdown of autophagy resulted in early escape from dormancy and recurrence. Interestingly, ATG5KD MMC contained an increased frequency of ADR-induced polyploid-like cells and rendered MMC resistant to immunotherapy. On the other hand, a transient blockade of autophagy did not affect the sensitivity of MMC to immunotherapy. Our observations suggest that while chemotherapy-induced autophagy may facilitate tumor relapse, cell-intrinsic autophagy delays tumor relapse, in part, by inhibiting the formation of polyploid-like tumor dormancy.
Although immunotherapy of breast cancer by means of anti-HER2 antibodies prolongs survival of breast cancer patients, disease recurrence remains a major challenge. On the other hand administration of human vaccines against infectious disease in a preventive setting or during latency/dormancy has been successful in offering a cure. Here, we sought to use adoptive immunotherapy (AIT) at the time of tumor dormancy in order to prevent progression of breast cancer. We used a low dose immunogenic chemotherapy by means of 5-FU, Adriamycin, and Cyclophosphamide (FAC) in order to stabilize tumor progression prior to AIT using autologous tumor-reactive lymphocytes. Low dose FAC established local tumor dormancy, inhibited distant tumor dormancy occurring long before distant metastasis, and induced predominate a Ki67- quiescent type of tumor dormancy, which is less susceptible to tumor immunoediting. Dormant tumor cells expressed the cell survival pathways, including the endothelin receptor/ligand (ETRA, ETRB and ET-1) and PD-L1, thereby protecting them from elimination by AIT. In addition, tumor-reactive CD8+ T cells also produced ET-1 as a survival ligand for ETRA positive tumor cells. A combination of AIT with the blockade of tumor cell survival pathways resulted in a significant improvement of AIT against tumor dormancy. We also showed that the inhibition Bcl-xL downstream of the tumor cell survival pathways is specifically effective against dormant tumor cells, suggesting a combination of AIT with small molecules inhibitors of Bcl-xL. Altogether, we showed that distant tumor dormancy is established long before distant recurrence of breast cancer, and that the expression of several tumor cell survival pathways in dormant cells protects them from immunotherapy. Our results suggest that immunotherapeutic targeting of tumor dormancy combined with the blockade of a common downstream cell survival pathway could prevent tumor progression and recurrence of the disease.
36
Nilsson, Johan. "Accurate description of heterogeneous tumors for biologically optimized radiation therapy." Doctoral thesis, Stockholm : Division of medical radiation physics, Department of oncology-pathology, Stockholm University and Karolinska Institutet, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-311.
Full text
37
lida, Takao, Naureen Mahbub Rahman, Akihiro Matsui, Hiromi Yamazawa, and Jun Moriizumi. "The Measurement of Size Distribution of Indoor Natural Radioactive Aerosols by Imaging Plate Technique." American Institite of Physics, 2008. http://hdl.handle.net/2237/12043.
Full text
38
Keinan, Sara, and Elma Zaklan. "Kartläggning av hjärnundersökningar med PET/CT på svenska universitetssjukhus : Redovisning av modalitetsuppbyggnad, undersökningsmetod och rekonstruktionsmetod samt stråldosjämförelse mellan PET och SPECT." Thesis, Hälsohögskolan, Högskolan i Jönköping, HHJ, Avd. för naturvetenskap och biomedicin, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-44453.
Full textAbstract:
Positron emission tomography/computed tomography (PET/CT) is a method that quantitatively visualizes physiological processes. The most common indications for PET brain are early diagnosis of various dementia types with 18F-Fludeoxyglucose (18F-FDG). The hospital in Jonkoping installed a new PET/CT and brain examinations have not yet been performed. The aim of the study was to map how hospitals in Sweden performed seven selected brain examinations with PET/CT focusing on modality structure, examination method and reconstruction method, with a comparison of radiation dose between PET/CT and single photon emission computed tomography/CT (SPECT)/CT. Out of the nine university hospitals selected, two were excluded. The method was prospective with quantitative approach and data was collected through a protocol. Compilation was made on Excel and the statistics were processed using the Wilcoxon Signed Ranks Test. The result showed similarities, for example reconstruction method and differences, for example fasting time. Effective dose was higher on SPECT than PET in examination of Parkinson's disease, however no significant difference (p = 0,059) was detected. Higher effective doses on SPECT was due to longer half-lives and greater dosages of Ioflupane (123I-Datscan) than 18F-FDG. For further studies, more hospitals and parameters in the protocol can be included.
39
Makola, Monwabisi F. "The Long Term Effects of Radiation Therapy on White Matter Integrity and Information Processing Speed: A Diffusion Tensor Imaging Study in Pediatric Brain Tumor Patients." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1504878431395029.
Full text
40
Campbell, Beth A. "Using Protective Orders To Combat Intimate Partner Violence: Are They Effective And Does Race Matter?" University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1530220497771792.
Full text
41
Ithisuphalap, Jaruda. "Does Endorsing Mistaken Belief Prior to Its Retraction Render the Correction More or Less Effective?" Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent1563877708913629.
Full text
42
Winer, Shawn. "Peptide dose, MHC affinity, and target self-antigen expression are critical for effective immunotherapy of nonobese diabetic mouse prediabetes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58826.pdf.
Full text
43
Mohd, Radzi Juliana Binti [Verfasser], and Frederik [Akademischer Betreuer] Wenz. "Treatment plan optimization based on biologically effective dose in Gamma Knife radiotherapy / Juliana Binti Mohd Radzi ; Betreuer: Frederik Wenz." Heidelberg : Universitätsbibliothek Heidelberg, 2021. http://d-nb.info/1225558077/34.
Full text
44
Eyden, Alison C. "The application of a semiconductor detector in the estimation of the effective dose in radiographic examination of the extremities." Thesis, University of Kent, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365250.
Full text
45
Tomlinson, Hayley. "Fear and anxiety in pregnancy and childbirth : how does it develop and what interventions are effective?" Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/9001/.
Full text
46
Soares, Maria Rosangela. "Avaliação dosimétrica de protocolos de exame de tomografia computadorizada de feixe cônico." Universidade Federal de Sergipe, 2016. https://ri.ufs.br/handle/riufs/5242.
Full textAbstract:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESThis PhD thesis, addresses the issue of evaluation of cone beam computed tomography, CBCT, scanning protocols, was introduced in dental radiology at the end of the 1990s, and it quickly became a fundamental examination for various procedures. Its main characteristic, the difference of medical CT is the beam shape. This study aimed to calculate the absorbed dose in eight tissues / organs of the head and neck, and to estimate the effective dose in 13 protocols and two techniques (stitched FOV e single FOV) of 5 equipment of different manufacturers of cone beam CT. For that purpose, a female anthropomorphic phantom was used, representing a default woman, in which were inserted thermoluminescent dosimeters at several points, representing organs / tissues with weighting values presented in the standard ICRP 103. The results were evaluated by comparing the dose according to the purpose of the tomographic image. Among the results, there is a difference up to 325% in the effective dose in relation to protocols with the same image goal. In relation to the image acquisition technique, the stitched FOV technique resulted in an effective dose of 5.3 times greater than the single FOV technique for protocols with the same image goal. In the individual contribution, the salivary glands are responsible for 31% of the effective dose in CT exams. The remaining tissues have also a significant contribution, 36%. The results drew attention to the need of estimating the effective dose in different equipment and protocols of the market, besides the knowledge of the radiation parameters and equipment manufacturing engineering to obtain the image.
Na presente tese de doutoramento foi abordada a temática da avaliação de protocolos de exame de tomografia computadorizada de feixe cônico - TCFC, que foi iniciada na radiologia odontológica no fim da década de 1990 e rapidamente tornou-se um exame fundamental para diversos procedimentos. Sua principal característica, que a diferencia da tomografia computadorizada médica, é a forma do feixe. Assim, este estudo objetivou calcular a dose absorvida em 8 tecidos/órgãos da cabeça e pescoço e estimar a dose efetiva em 13 protocolos e duas técnicas (stitched FOV e single FOV) de 5 equipamentos diferentes fabricantes de tomografia computadorizada de feixe cônico. Para isto, foi utilizado um simulador antropomórfico feminino, representando uma mulher padrão, onde foram inseridos dosímetros termoluminescentes em diversos pontos, representando órgãos e tecidos com valores de ponderação apresentados na norma ICRP 103. Os resultados foram avaliados, comparando-se a dose de acordo com o objetivo da imagem tomográfica. Dentre os resultados, observou-se uma diferença de até 325 % de dose efetiva em relação a protocolos com o mesmo objetivo de imagem. Em relação à técnica de obtenção de imagem, a técnica stitched FOV resultou em uma dose efetiva até 5,3 vezes maior que a single FOV para protocolos com o mesmo objetivo de imagem. Na contribuição individual, as glândulas salivares são responsáveis por 31% da dose efetiva, nos exames tomográficos. Os tecidos restantes também apresentaram uma contribuição significativa, 36 %. Os resultados apontam a necessidade de se estimar a dose efetiva nos diversos equipamentos e protocolos presentes no mercado, além de conhecer os parâmetros de radiação e a engenharia de fabricação dos equipamentos para a obtenção da imagem.
47
Bacchim, Neto Fernando Antonio. "Caracterização das exposições ocupacionais e eficiência da dosimetria pessoal em radiologia intervencionista vascular." Botucatu, 2017. http://hdl.handle.net/11449/190996.
Full textAbstract:
Orientador: Diana Rodrigues PinaResumo: A Radiologia Intervencionista (RI) é a área da medicina que proporciona as maiores exposições ocupacionais. Os valores de dose aos quais os intervencionistas são expostos são difíceis de padronizar. Nesta pesquisa apresentamos uma avaliação completa das exposições ocupacionais e determinamos a eficiência de distintos métodos de dosimetria pessoal utilizados na RI. Essa pesquisa foi abordada em 2 etapas, conforme descrito a seguir: A primeira etapa se baseou em caracterizar as exposições ocupacionais em diferentes modalidades de procedimentos de RI vascular para duas categorias de profissionais e estimar o número de procedimentos anuais que cada profissional pode realizar sem exceder os limites de dose. Foi avaliada a exposição ocupacional, através de dosimetria termoluminescente, em diferentes partes do corpo (cristalino, tireoide, tórax, abdômen, pés e mãos) de duas categorias de intervencionistas (principais e assistentes) em três modalidades diferentes de procedimentos de RI vascular. As maiores doses equivalentes foram encontradas para as mão de ambos os profissionais, podendo chegar a aproximadamente 9 mSv em um único procedimento. Algumas regiões dos profissionais em alguns procedimentos podem receber, durante o ano, níveis de doses perigosamente perto dos limites anuais. Dosímetros posicionados no tórax podem subestimar as doses para outras regiões do corpo, especialmente abdômen, extremidades e cristalinos. Na segunda etapa foram avaliadas as eficiências de 6 diferent... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Interventional Radiology (IR) is the area of medicine that provides the largest occupational exposures. The dose values to which interventionists are exposed are difficult to standardize. In this research we present a complete evaluation of occupational exposures and determine the efficiency of different personal dosimetry methods used in IR. This research was performed in 2 stages, as described below: The first step was to characterize the occupational exposures in different modalities of vascular IR procedures for two categories of professionals. We also estimated the number of annual procedures that each professional can perform without exceeding the dose limits. Occupational exposures were evaluated in different body parts (crystalline, thyroid, thorax, abdomen, feet and hands) by two interventional categories (primary and assistants) in three different modalities of vascular IR procedures. The highest equivalent doses were found for the hands of both professionals, reaching approximately 9 mSv in a single procedure. Some regions of professionals in some procedures may receive dose levels during the year dangerously close to annual limits. Dosimeters positioned in the chest may underestimate the doses to other regions of the body, especially the abdomen, extremities and crystalline. The second stage, we evaluated the efficiencies of 6 different personal dosimetry methodologies used internationally to estimate the effective dose received by interventional professionals. An... (Complete abstract click electronic access below)
Mestre
48
Musiza, Charlene Tsitsi. "Does the growth of ICT in Zimbabwe present an opportunity for effective use of intellectual property rights?" Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/16711.
Full textAbstract:
Includes bibliographical referencesIn 2005 the Government of Zimbabwe adopted a National Information and Communications Technology (ICT) Policy to spur growth in the ICT sector. The idea was to transform Zimbabwe into a knowledge - based economy by 2020. This saw some synergies between stakeholders in improving ICT infrastructure. In the last decade Zimbabwe has seen growth in ICT albeit with numerous challenges. There have been innovation s in ICT which raise possible intellectual property issues. The thesis seeks to assess whether there is scope for the utilisation of intellectual property rights in some of the innovations. An exploration of the various policies that have a bearing on ICT will inform the discussion on ICT growth. The thesis will also lay out the intellectual property framework and identify rights which can be appropriated to innovations. It will identify some areas where tailoring is required to suit the system to the development needs of the country and the innovation environment. Some recommendations will be made derived from the experiences of other countries and from the survey conducted as part of the research.
49
Gasser, Estelle. "Spectrométrie gamma au laboratoire et in situ : développements et applications environnementales." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAE007/document.
Full textAbstract:
La spectrométrie γ dose en une seule mesure tous les émetteurs γ dans un échantillon. L’auto-absorption des rayonnements γ dans des échantillons se manifeste par des pertes ou des gains d'impulsions. Pour caractériser une nouvelle géométrie de comptage, des améliorations du dispositif existant ont été apportées par des simulations MCNPX. Avec ce nouveau dispositif nous avons pu spécifier les doses absorbées et efficaces annuelles ainsi que les facteurs de conversion de dose des radioisotopes naturels pour des matériaux de construction et des prélèvements de sols. Des simulations ont montré l’influence des seuils de détection des rayonnements γ donc sur les facteurs de conversion de dose et la nécessité d’une mise à jour de ces facteurs. L’analyse par spectrométrie γ in situ du sol fait appel à des efficacités de détection simulées par MCNPX pour une source aux dimensions semi-infinies. Une application a été réalisée autour d’une centrale nucléaire et une autre pour une sociétéΓ-ray spectrometry enables determining all γ-ray emitters in a sample with a single measurement. Self-absorption of γ-rays in samples is manifest by a loss or a gain of pulses that results in a poor estimation of the counting efficiency. To characterize a new counting geometry improvements of the existing set-up were made with MCNPX simulations. With the new geometry we could specify absorbed and annual effective doses as well as dose conversion factors for the natural radioisotopes of several building materials and soil samples. Simulations show the influence of detection limits of γ-radiation on dose conversion factors and the need for updating these factors. γ-ray measurements of soil in situ require different counting efficiencies simulated by MCNPX for a semi-infinite source. Two in-situ soil analyses were made, one around a nuclear power and the other for a private company
50
Saukko, E. (Ekaterina). "Medical use of radiation in gastroenterology:optimising patient radiation exposure during endoscopic retrograde cholangiopancreatography (ERCP)." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526221083.
Full textAbstract:
Abstract Fluoroscopically guided procedures are currently an area of special concern in relation to radiation protection, as they may produce a high radiation dose to patients and increase the risk of skin injury. ERCP is a gastrointestinal procedure used as a gold standard in the treatment of pancreatobiliary disorders. It is performed under endoscopic and fluoroscopic guidance. Recently, both the number and the complexity with associated increased technical difficulty of therapeutic ERCP procedures have significantly increased. The present study aimed to assess the medical use of radiation in ERCP, with special emphasis on optimisation of radiation protection of patients. For this purpose, the level of patient radiation exposure during ERCP was evaluated by registering the radiation dose indices in Finnish hospitals. The entrance surface dose was measured by thermoluminescent dosimeters and the effective dose was estimated using conversion coefficients. For dose optimisation and for quality assurance, the local diagnostic reference levels (DRL) for ERCP were established and reviewed after five years. A single centre prospective analysis was conducted to identify patient-, procedure- and operator-related factors affecting dose area product (DAP) and fluoroscopy time (FT). The results showed a large variation of dose indices in overall, as among participating hospitals due to differences in patient characteristics, operator, equipment and procedural complexity. The risk of radiation-induced skin injury and the lifetime cancer risk seems to be reasonably low, indicating ERCP to be a low-dose study. Local DRL is an effective tool in the optimisation process, as a certain degree of dose reduction was achieved during the years. Multiple factors were found to affect DAP and FT in ERCP. The awareness of these factors may help to predict possible prolonged procedures that cause a higher radiation dose to the patient and thus facilitate the use of appropriate precautionsTiivistelmä Säteilysuojelun näkökulmasta läpivalaisuohjauksessa tehtävät toimenpiteet ovat erityisen huolen aiheena, koska ne voivat aiheuttaa potilaille suuria säteilyannoksia ja siten lisätä ihovaurion riskiä. ERCP on ruoansulatuskanavan endoskopiatoimenpide, jota käytetään haima- ja sappitiesairauksien hoidossa kultaisena standardina. ERCP suoritetaan duodenoskoopilla läpivalaisukontrollissa. Viime vuosina ERCP toimenpiteiden määrät ja toimenpiteiden monimutkaisuus ovat kasvaneet merkittävästi lisääntyneen teknisen haastavuuden vuoksi. Tutkimuksen tarkoituksena oli arvioida säteilyn lääketieteellistä käyttöä ERCP:ssa, kiinnittäen eritystä huomiota potilaan säteilysuojelun optimointiin. Potilaan säteilyaltistuksen tasoa ERCP:ssa arvioitiin keräämällä potilasannoksia suomalaisista sairaaloista, pinta-annokset mitattiin termoloistedosimetreilla ja efektiivinen annos laskettiin muuntokertoimilla. Säteilyaltistuksen optimointi- ja laadunvalvonnan työkaluksi ERCP:lle asetettiin paikalliset vertailutasot ja ne tarkistettiin 5 vuoden kuluttua. Potilaaseen, toimenpiteeseen ja toimenpiteen suorittajaan liittyvät tekijät, jotka vaikuttavat annoksen ja pinta-alan tuloon (DAP) sekä läpivalaisuaikaan, selvitettiin retrospektiivisesti yhdessä sairaalassa. Tutkimuksen tulokset osoittivat, että potilaan säteilyannoksissa oli suurta vaihtelua niin yleisesti, kuin osallistuvien sairaaloiden välillä. Vaihtelu johtui potilaan ominaisuuksista, erilaisista läpivalaisulaitteista, toimenpiteen suorittajista ja ERCP toimenpiteiden vaikeusasteesta. Säteilyn aiheuttaman ihovaurion riski ja elinikäinen syöpäriski näyttäisi tulosten perusteella olevan kohtuullisen alhainen, mikä osoittaa, että ERCP on matala-annostutkimus. Paikallinen vertailutaso osoittautui tehokkaaksi optimointityökaluksi, sillä annostason lasku ERCP:ssa saavutettiin vuosien kuluessa. Useiden tekijöiden todettiin vaikuttavan DAP:n ja läpivalaisuaikaan ERCP:ssa. Näiden tekijöiden tiedostaminen voi auttaa tunnistamaan etukäteen ne haastavat ERCP toimenpiteet, jotka voivat aiheuttaa suuria säteilyannoksia potilaille, ja siten mahdollistaa niihin varautumisen