Com a liberação do uso da energia nuclear para aplicações pacíficas, a Comissão Internacional de Proteção Radiológica, CIPR, fundada em 1928, criou em 1958 um sistema de proteção às doses de radiação ionizante indesejáveis causadas aos trabalhadores, indivíduos de público e meio-ambiente para viabilizar a introdução dessas aplicações. Esse sistema de proteção é adotado pelo Organismo Internacional de Energia Atômica, OIEA, que publica recomendações em séries de segurança, SS e pela Comissão Nacional de Energia Nuclear, CNEN, que publica regulamentações em normas. Essas recomendações internacionais e regulamentações nacionais passaram por adaptações e necessitam ser aplicadas dessa forma. O presente trabalho utiliza recomendações da publicação 75 da CIPR, da publicação 115 da SS e regulamentações da norma NN 3.01 da CNEN para apresentar, através de medidas de radioproteção, o controle das doses de radiação ionizante para trabalhadores em uma instalação radiativa que trabalha com pesquisa, produção, fracionamento e embalagem de fontes não-seladas para uso clínico. Dessa forma, é possível prevenir adequadamente as doses indesejáveis e confirmar as doses recebidas. / With the liberation of the use of the nuclear energy for peaceful applications, International Commission Radiological Protection, ICRP, founded in 1928, created a system of protection of the undesirable doses of ionizing radiation in 1958. This has been received by workers, members of the public and environment and hence it became possible for the introduction of these applications. This protection system is adopted by the International Agency of Energy Atomic, IAEA, that publishes recommendations in safety series, SS and by the Comissão Nacional de Energia Nuclear, CNEN, which publishes these regulations. The international recommendations and national regulations were adapted and they need to be applied in this way. The present paper uses recommendations of the publication 75 from ICRP, of the publication 115 from SS and regulations of the regulation NN 3.01 from CNEN to present, through radiological protection measures, the ionizing radiation dose control for workers in a nuclear plant that works in the research, production, division and packing of unsealed sources to be used in clinical applications. In that way it is possible to prevent appropriately the undesirable doses and to confirm the received doses.

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Medicine in Diagnostic Radiology Johannesburg 2019 / Introduction: Neonates in a neonatal ICU or high care unit are a high-risk population. Besides a vulnerability to medical and surgical conditions, which often require radiological investigation, they are also at risk from the effects of radiation used in imaging. These risks increase with radiation dose. Numerous studies have assessed the dose due to primary radiation, however few have assessed the secondary radiation dose, and none have quantified the dose over time. Aim: To quantify the secondary radiation dose in our neonatal high care unit in order to determine if additional protective measures from secondary radiation are necessary. Method: A prospective analytic study was undertaken using multiple thermoluminescent devices in a cubicle of a neonatal high care unit, and control dosimeters outside the unit. Dosimeters were deployed for a 4 week period. Simultaneously, data was collected on patient numbers, and the X-rays performed in the unit. Results were compared to reference ranges for primary and secondary radiation (2-3 mSv per annum). Results: The average secondary radiation dose was 0.108mGy (p=0.6553) over 4 weeks, less than the expected background radiation dose of 0.17 – 0.25mGy. There was a large number of patients moving through the unit during the study period (89), with an average of 14 patients in the unit at a time, however this did not result a large number of X-ray exposures. Twenty one percent of patients were in the unit for less than a day, and 49 % were admitted for less than 3 days. Sixteen patients (18%) had X-ray investigations, with a total of 21 investigations and 30 exposures. Thirty percent of primary radiation dose was due to repeat exposures. Patients receiving X-rays had an average of 2 X-ray examinations (range: 1 to 4 studies) performed, with an average Entrance Skin Dose of 196.7µSv (0.197mGy) – range 77 to 554µSv (0.077mGy to 0.554mGy). There was no statistically significant difference between weeks or zones (p=0.1060 and p=0.8237 respectively), and differences in primary radiation doses was likely due to chance. Conclusion: Additional measures to protect patients in the unit from secondary radiation are unnecessary. There was a low probability of patients having a radiological investigation in the neonatal high care unit, and secondary radiation doses were not measurably higher than background radiation. / TL (2019)

No / Radiographers and other healthcare professionals are becoming increasingly involved in radiological reporting, for instance plain radiographs, mammography and ultrasound. Systematic reviews of research evidence can help to assimilate a knowledge base by ordering and evaluating the available evidence on the reporting accuracy of different professional groups. This article reviews the biases that can undermine the results of plain ¿lm reading performance studies. These biases are subdivided into three categories. The ¿rst category refers to the selection of subjects, including both ¿lms and professionals, and covers the validity of generalizing results beyond the study population. The other two categories are concerned with study design and the interpretation both of ¿lms and of reports and the effect on study validity. An understanding of these biases is essential when designing such studies and when interpreting the results of existing studies.

It remains unlikely that a terrorist organization could produce or procure an actual nuclear weapon. However, the construction of a radiological dispersal device (RDD) from commercially produced radioactive sources and conventional explosives could inflict moderate human casualties and significant economic damage. The vast availability of radioactive sources and the nearly limitless methods of dispersing them demand an inclusive study of the acquisition pathways for an RDD. A complete network depicting the possible acquisition pathways for an RDD could be subjected to predictive modeling in order to determine the most likely pathway an adversary might take. In this work, a comprehensive network of RDD acquisition pathways was developed and analyzed utilizing the Bayesian network analysis software, Netica. The network includes variable inputs and motivations that can be adjusted to model different adversaries. Also, the inclusion of evidence nodes facilitates the integration of real-time intelligence with RDD plot predictions. A sensitivity analysis was first performed to determine which nodes had the greatest impact on successful completion of RDD acquisition. These results detail which portions of the acquisition pathways are most vulnerable to law enforcement intervention. Next, a series of case studies was analyzed that modeled specific adversarial organizations. The analysis demonstrates various features of the constructed Bayesian RDD acquisition network and provides examples of how this tool can be utilized by intelligence analysts and law enforcement agencies. Finally, extreme cases were studied in which the adversary was given the maximum and minimum amount of resources in order to determine the limitations of this model. The aggregated results show that successful RDD acquisition is mostly dependent on the adversary’s resources. Furthermore, the network suggests that securing radiological materials has the greatest effect on interdicting possible RDD plots. Limitations of this work include a heavy dependence on conditional probabilities that were derived from intuition, as opposed to actual historical data which does not exist. However, the model can be updated as attempted or successful RDD plots emerge in the future. This work presents the first probabilistic model of RDD acquisition pathways that integrates adversary motivations and resources with evidence of specific RDD threats.

In the aftermath of the nuclear accidents at Chernobyl in Russia, at the Three Mile Island reactor in the United States and the nuclear criticality accident at the Tokai-mura JCO in Japan, the need for serious attention has been directed toward response planning for nuclear emergencies. Currently Taiwan has one of the highest population densities in the world. To handle energy needs, there are three nuclear facilities. Recently the first serious electrical failure occurred at the third nuclear reactor (3A). This incident in particular brought the need for proper measures to handle accidents to the attention of the public. The main purpose of this thesis is to investigate the effectiveness of the national planning for handling nuclear emergencies under the existing laws for nuclear accident emergency response and the laws for disaster prevention at the local government level. Attention is given to the capability of the design and organizational system for handling nuclear emergencies and whether this plan can be realized in actual practice. Having reached a thorough understanding through the analysis, the paper makes suggestions about the procedures to be followed for the national government¡¦s handling of nuclear plant emergencies.

Physicians often utilize different imaging techniques to provide clear, visual information about internal parts of the patient. Since the different imaging modalities give different types of information, the combination of them serves as a powerful tool while determining the diagnosis, planning of treatment or during therapy follow-up. To simplify the interpretation of the image information, image registration is often used. The goal of the registration is to put different images in a common coordinate system. It is essential that the registration between the images is accurate. Normalized Mutual Information (NMI) is a metric that quantifies the conformity between images. Even though NMI is a robust method it is often dominated by large structures as the external contour of the patient as well as by the structures of the bones. The prostate is an organ that does not have a fixed position relative to the other organs and host small amounts of image information. The accuracy of the registration is therefore limited with respect to the prostate when using the whole image volume. This master thesis investigates the possibility to restrict the part of the image used for registration to a small volume around the prostate with goal to receive a better registration of the prostate than if full sized images are used. A registration program, utilizing NMI, was written and optimized in MatLab. Four Magnetic Resonance (MR) series and one Computed Tomographic (CT) series where taken over the pelvic area of five patients with the diagnosis prostate cancer. The prostate were delineated by a physician. By adding margin to the delineations five different sized Regions of Interest (ROI) where created.  The smallest ROI precisely covered the prostate while the largest covered the whole image. The deviation in Center of Mass (CoM) between the images and the Percentage Volume Overlap (PVO) were calculated and used as a measure of alignment. The registrations performed with sub-volumes showed an improvement compared to those that used full-volume while registering a MR image to another MR image. In one third of the cases a 2 cm margin to the prostate is preferable. A 3 cm margin is the most favorable option in another third of the cases. The use of sub-volumes to register MR images to CT series turned out to be unpredictable with poor accuracy. Full sized image registration between two MR image pairs has a high precision but, due to the motion of the prostate, poor accuracy. As a result of the high information content in the MR images both high precision as well as high accuracy can be achieved by the use of sub-volume registration. CT images do not contain the same amount of image information around the prostate and the sub-volume based registrations between MR and CT images are hence inconsistent with a low precision.  

M.Tech. (Radiography) / Systematic implementation of a quality control (QC) programme is crucial for any diagnostic radiology department if consistent optimal equipment performance, quality images, accurate diagnosis and quality services at optimum radiation dose and costs are to be assured. This highlighted the necessity for the Tanzania Atomic Energy Commission (TAEC) to establish a training programme to enable radiographers to implement a QC programme and associated QC measures in their departments. Most radiographers have been trained on the QC programme, however, the level of QC implementation by the radiographers is not established. The aim of this study was to investigate the extent to which the QC programme and associated QC measures are being implemented by radiographers in conventional diagnostic radiography units, in Tanzania. A quantitative cross-sectional study design, using a questionnaire, was conducted on a sample of radiographers who have been trained on the QC programme, and who were practicing in hospitals within Tanzania. The study found that implementation of the QC programme and associated QC measures was poor. Most QC measures were not being performed and that only a few tests were being performed but not consistently. Furthermore, there were no records and procedures available for the QC programme. The challenges identified were negligence by the radiographers, lack of standardized test tools, lack of hospital managerial support, lack of enforcement and lack of motivation and coordination. Multifactor interventions by the TAEC, Ministry of Health and Social Welfare, radiographers and the hospital management teams are needed to improve the implementation of the QC programme.

O Instituto de Pesquisas Energéticas e Nucleares, IPEN, pesquisa e produz radiofármacos que são distribuídos para todo o Brasil. Atualmente o radiofármaco com a maior quantidade de embalados expedidos por ano e com a maior atividade total é o gerador de tecnécio-99m. Com o intuito de diminuir as doses individuais dos trabalhadores envolvidos na produção de radiofármacos foi realizado um estudo de otimização da proteção radiológica no processo de expedição do gerador de tecnécio-99m, utilizando as técnicas de análise de custo-benefício diferencial, análise de custo-benefício integral, análise de prioridade com atributos múltiplos e análise com critérios múltiplos excedentes. Com alterações na configuração do embalado para despacho do gerador e com a aquisição de uma esteira transportadora foi possível estabelecer 4 opções de proteção. Os atributos considerados foram o custo da proteção, a dose coletiva, a dose individual e o esforço físico realizado pelo trabalhador para movimentar o embalado na falta da esteira. Para verificar a robustez das soluções analíticas encontradas com as técnicas utilizadas na otimização foi realizado um estudo de sensibilidade e foi constatado que a opção 3 é mais robusta que a opção 1, que deixa de ser a solução analítica com um aumento de R$ 20.000,00 no custo da proteção. / The Instituto de Pesquisas Energéticas e Nucleares, IPEN, radiopharmaceuticals research and produce that are distributed throughout Brazil, currently the radiopharmaceutical with the largest number of packaged shipped per year and with the highest total activity is the 99m technetium generator. To reduce individual doses for workers involved in the production of radiopharmaceuticals was performed a study of radiological protection optimization in the shipment process of technetium generator, using the techniques: diferencial cost-benefit analysis, integral cost-benefit analysis, multi-attribute utility analysis and multi-criteria outranking analysis. With changes in the configuration of packed for generator dispatch and with the acquirement of a mat transporter it was possible establish 4 protection options. The attributes considered were the protection cost, collective dose, individual dose and physical effort by worker to move the package without the mat. To assess the robustness of analytical solutions found with the techniques used in the optimization we performed a sensitivity study and found that option 3 is more robust than option 1, which is no longer the analytical solution with an increase of R$ 20.000,00 the cost of protection.

Introduction: Unicompartmental knee replacements (UKRs) are an alternative to total knee replacements (TKRs) for treating isolated medial compartment knee osteoarthritis. However, revision rates are consistently higher than for TKR and UKRs are commonly revised for “unexplained” pain, a possible cause of which is elevated proximal tibial bone strain. The influence of implant design on this strain has not been previously investigated. Aims: The aims of this thesis are to determine the effect of medial UKR tibial component design on proximal tibial strain and ongoing pain. Methods: A retrospective clinical cohort study was performed comparing patient reported outcome and implant survival of a metal backed mobile bearing UKR implant (n=289) and an all-polyethylene (AP) fixed bearing UKR implant (n=111) with minimum 5 year follow up. A method of digital radiological densitometry, the greyscale ratio b (GSRb), was developed, validated and applied to plain radiographs to measure changes in bone density over 5 years in both the metal backed (n=173) and all-polyethylene (n=72) UKR patients. A finite element model (FEM) was validated against previous mechanical testing data and was used to analyse the effect of metal backing and implant thickness on proximal tibial cancellous bone strain in fixed bearing UKR implants. Results: There were no significant differences in patient reported outcomes between implants throughout follow up. Ten year all cause survival was 90.2 (95%CI 86-94) for the metal backed implant and 79.9 (60.7 to 99) for the all-polyethylene. Revision for unexplained pain was significantly greater in the AP implant where revisions were performed significantly earlier. Overall, the mean GSRb reduced following medial UKR with no difference between implants. In those patients where GSRb increased, patient reported outcomes were worse with an association with ongoing pain. A finite element model was successfully validated using acoustic emission and digital image correlation data. This model confirmed that the volume of cancellous bone exposed to compressive and tensile strains in excess of 3000 (pathological overloading) and 7000 (fracture) microstrain were higher in the AP implants, as were peak tensile and compressive strains. Varying polyethylene insert thickness did not affect these strain parameters in the metal backed implant, but varying polyethylene thickness in the AP implants had significant effects at all loads with elevated strains in thinner implants. Increasing the AP thickness to 10mm did not reduce strains to the levels found under metal backed implants, and imminent cancellous bone failure was implied when AP thickness was reduced to 6mm. Conclusion: UKRs with all-polyethylene tibial components are associated with greater proximal tibial strains than metal backed implants and this is exacerbated in thinner implants. The clinical consequences of this are uncertain. Medial UKR implantation does alter proximal tibial GSRb, though this is not uniform and is independent of implant type. When GSRb increases it is associated with ongoing pain.

As doses de radiação ionizante para os trabalhadores no transporte de material radioativo devem ser tão pequenas quanto razoavelmente exequível. As doses médias dos motoristas e carregadores amostrados neste trabalho devem ser diminuídas. A demonstração do controle das doses em veículo rodoviário com material radioativo, requisitada pelo regulamento brasileiro atual, norma CNEN NE 5.01, é apresentada em formulário próprio com valores de exposição obtidos em posições de ocupação regular de indivíduos do público e de trabalhadores, mesmo quando se expede veículo sem a necessidade de uso exclusivo (∑ IT 50). Este trabalho mostra, por meio de pesquisa bibliográfica, elaboração de modelos e pesquisa de campo, que esta demonstração do controle com a obtenção dos valores de exposição nesta situação, para um método de controle melhor, deve ser realizada pela apresentação do registro do acúmulo de cargas, limitado (∑ IT 50), a fim de evitar a obtenção destas medidas, para que haja padronização com regulamentos estrangeiros e para que os custos e os tempos, importantes para expedição de radiofármacos com meia-vida curta, e também as atuais doses laborais dos técnicos de radioproteção sejam todos diminuídos. Os valores de exposição dos parâmetros utilizados com esse método são menores do que seus limites regulamentares. Para contribuir com essas finalidades devem ser apresentadas pelo regulamento brasileiro atualizado as distâncias de segregação entre as cargas e as cabines dos veículos. / The radiation doses to workers in the transport of radioactive material should be as low as reasonably achievable. The average doses of drivers and loaders, sampled in this thesis should be decreased. The demonstration of doses control in a road vehicle with radioactive material required by the current Brazilian regulation, CNEN NE 5.01 should be written in its own printed form with exposure values obtained in normally occupied positions from workers and members of the public, even when the consignment does not need \"exclusive use\" (∑ IT 50). Through bibliographic research, modeling and field research, this research work shows that this demonstration of the control should be done by writing the registration accumulation of load, limited (∑ IT 50), also in the own printed form. It is for a better control method, in order to avoid the use of measuring equipment, to build standardization with foreign regulations, to the current occupational doses of radioprotection technicians, the costs and time, (important for consignment with radiopharmaceuticals short half-life) would be all smaller. Exposure values of the parameters used with this method are smaller than regulatory limits. The segregation distances between loads and the cabins of vehicles shall be showed by Brazilian regulation updated to contribute to these aims.