Para as análises de imagens mamográficas, médicos radiologistas fazem uso de monitores médicos especializados, capazes de proporcionar laudos seguros, uma vez que devem oferecem resolução adequada, níveis corretos de luminância e contraste dentro do padrão DICOM - Digital Imaging and Communications in Medicine (Comunicação de Imagens Digitais na Medicina). Este trabalho teve como objetivo avaliar a qualidade dos monitores específicos para mamografia digital, através de testes propostos pelo Report N 3 da American Association of Physicists in Medicine AAPM usando medidores calibrados de luminância (fotômetro) e padrões TG18 em testes quantitativos e qualitativos. Avaliou-se as condições de luz ambiente e outros indicadores básicos de desempenho, como, distorção geométrica, ruído, resolução, reflexão, uniformidade da luminância, o cumprimento resposta contraste de luminância para padrão DICOM e padrão anatômico das mamas. Em resposta, o teste que mais apresentou não conformidade foi à variação excessiva com o padrão de resposta contraste DICOM Grayscale Standard Display Function (GSDF), apresentando não conformidade em (100%) dos monitores analisados. Nos demais testes, todos os monitores de 5MP e o de 3MP apresentaram conformidade nos parâmetros avaliados. Em uma ação corretiva para as não conformidades, indica-se a realização de calibrações e procedimentos de verificação de controle de qualidade feitas por profissionais capacitados ou orientados. / For the analysis of mammographic images, radiologists make use of specific medical monitors, able to provide insurance reports, as they offer appropriate resolution, correct levels of luminance and contrast within the standard DICOM - Digital Imaging and Communications in Medicine (Communication Images digital in Medicine). This study aims to evaluate the quality of specific monitors for digital mammography, by testing the calibrated luminance meters (photometer) and TG18 standards in quantitative and qualitative methods proposed by Report No. 3 of American Association of Physicists in Medicine AAPM. It was evaluated the ambient light conditions and other basic performance indicators, such as, the as geometric distortion, noise, resolution, reflection, luminance uniformity, contrast luminance response compliance to DICOM standard and anatomical pattern of the breasts. The results showed that non-compliance test fails when visualizing low-contrast objects (100% of monitors analyzed) in the response pattern contrast DICOM Grayscale Standard Display Function (GSDF). For the other tests, all monitors of 5 and 3MPixel presented in agreement to the evaluated parameters. For a further corrective action for instance, non-compliance, it may be indicate to perform calibrations and verification of quality control developed by trained or oriented professionals.

Nenhuma / 3-Desoxi-3-[18F]Fluor-Timidina (18FLT) é um análogo radioativo do nucleosídeo timidina usado desde 1998 em exames de tomografia por emissão de pósitrons (PET) para diagnóstico de vários tipos de tumores, como de mama, pulmonar, colorretal, cerebral, entre outros. Seu uso amplia a cobertura dos exames PET em diagnóstico de câncer, já que existem limitações da [18F]Fludesoxiglicose (18FDG), o radiofármaco PET mais usado no mundo atualmente. Para implementação da produção de 18FLT, na Unidade de Pesquisa e Produção de Radiofármacos do Centro de Desenvolvimento da Tecnologia Nuclear (UPPR/CDTN), o módulo de síntese de 18FDG foi adaptado usando-se 3 protocolos nos quais se variou a concentração de etanol (0; 8 e 10% V/V). Também foram desenvolvidos testes de Controle de Qualidade, como pH, determinação de catalisador, determinação de etanol e acetonitrila, pureza química e radioquímica, entre outros. A formulação foi avaliada in vitro quanto a sua segurança, pelos ensaios de viabilidade metabólica (MTT) e toxicidade clonogênica, e quanto a sua eficácia para a detecção de tumores pelo ensaio de interação (Binding). Os rendimentos corrigidos obtidos da síntese de 18FLT foram 6,52%; 253% e 233% para o 1, o 2 e o 3 protocolo, respectivamente. O produto do protocolo 3 (Etanol 8%) apresentou menor citotoxicidade no teste in vitro MTT do que o do segundo (Etanol 10%). Além disso, a formulação de 18FLT e as impurezas químicas presentes na mesma não afetaram a clonogenicidade das células testadas. Com base nestes resultados o protocolo 3 foi escolhido como a síntese padrão de 18FLT. A interação da 18FLT com as linhagens celulares foi saturável, com ligação específica maior que 90%, atestando a eficácia do radiofármaco na detecção de tumores. A afinidade do radiofármaco 18FLT por células de glioblastoma humano (U87MG) foi da ordem de 0,24 μmol/L (Kd). Por fim, constatou-se que quantidades adicionais de timidina e clorotimidina, duas impurezas presentes na formulação, reduziram significativamente a interação de 18FLT (IC50 ~ 1 - 34 μmol/L) com as células tumorais, o que pode reduzir sua eficácia para o diagnóstico. Assim, sugere-se que um valor máximo seja estabelecido para a concentração destas impurezas como um dos critérios de Pureza Química de 18FLT, baseando-se no ensaio de eficácia de interação. Portanto, a UPPR/CDTN está apta a fornecer rotineiramente o radiofármaco 18FLT para estudos não clínicos e clínicos, de acordo com os requisitos de Boas Práticas de Fabricação de Medicamentos exigidos pela ANVISA. / 3-Deoxy-3-[18F]Fluorothymidine (18FLT) is a Thymidine radioactive analog that is being used since 1998 for cancer diagnostics by Positron Emission Tomography (PET) for several types of cancer, as breast, lung, colorectal, brain, among others. Its use extends coverage of PET scans in diagnosis of cancers in certain organs and tissues, since there are limitations of [18F] Fludeoxyglucose (18FDG), which is the most used PET radiopharmaceutical in the world today. An 18FDG synthesis module was adapted to implement 18FLT production in Research and Production Unit of Radiopharmaceuticals from Center of Nuclear Technology Development (UPPR/CDTN). Three protocols were used varying the concentration of ethanol (0%, 8% and 10%). Quality control tests were also developed, as pH, catalyst determination, ethanol and acetonitrile determination, chemical and radiochemical purity, amongst others. The formulation was evaluated in vitro for its safety, using the metabolic viability (MTTs assay) and clonogenic toxicity assays, and for its effectiveness in tumors, using the binding test. The corrected yields were 6.52%; 253%; and 233% for the first, second and third synthesis protocols, respectively. The third protocol (Ethanol 8%) was found to be less cytotoxicity comparing to the second one (Ethanol 10%). Furthermore, 18FLT chemical impurities and the entire formulation did not affect the clonogenicity of the cells in Clonogenic Assay. Based on these results the protocol 3 was chosen as the standard 18FLT synthesis. The interaction of 18FLT with the cell lines was saturable, with specific binding higher than 81%, confirming the effectiveness of the radiopharmaceutical in tumor detection. The affinity between 18FLT and human glioblastoma cells (U87MG) was found to be 0.24 μmol/L (Kd). Finally, it was found that additional quantities of thymidine and chlorothymidine reduced significantly 18FLT interaction (IC50 ~ 1 - 34 μmol/L) with tumor cells, which can reduce its effectiveness in PET diagnosis. For this reason it is suggested that a maximum value must be set for the concentration of these impurities in the 18FLT Chemical Purity quality control test based in efficacy binding assays. Therefore, CDTN is able to routinely provide 18FLT radiopharmaceutical for clinical and non clinical studies, according to the Brazilian Good Manufacturing Practices for Radiopharmaceuticals required by ANVISA.

OBJETIVO: A imagem molecular de transportadores de dopamina (DAT) oferecer uma informação diferencial na investigação de doenças neurodegenerativas, como a Doença de Parkinson, diante de uma sólida abordagem quantitativa. Porém, são diversos o número de diferentes métodos semiquantitativos aplicados na prática clínica, que nos quais podem produzir resultados distintos quando aplicados por diferentes avaliadores ou condições de avaliação da imagem de SPECT do corpo estriado. Logo, este estudo pode avaliar a acurácia, precisão e reprodutibilidade de diferentes métodos semiquantitativos de imagens de SPECT do corpo estriado. MATERIAIS E MÉTODOS: Foram realizadas 23 aquisições de SPECT utilizando um simulador antropomórfico estriatal preenchido com diferentes concentrações de atividade de 99mTc. A preparação deste simulador estriatal foi realizada a partir de concentrações de atividades nas cavidades de interesse (núcleo caudado, putâmen e corpo estriado) proporcionalmente maiores do que a da cavidade de referência (background). As imagens foram reconstruídas utilizando parâmetros ideais já protocolados. Cinco métodos baseados em ROIs, dedicados para a quantificação de SPECT do corpo estriado foram avaliados: ROIs desenhadas sobre as imagens de SPECT - (A) Manual, ROIs com dimensões padronizadas - (B) método Twobox e (C) método Threebox; e baseado em imagens estruturais (D) MRI e (E) CT. A acurácia de cada método aplicado foi avaliada através do coeficiente de correlação de concordância (CCC), sua precisão utilizando o coeficiente de Pearson e modelos regressão linear, assim como a reprodutibilidade pode ser investigada através de análises de variabilidade intra- e interobservadores. RESULTADOS: Tanto para as cavidades avaliadas de forma individual (Caudado e Putâmen), quanto para o corpo estriado como um todo, todos os métodos aplicados apresentaram um aumento no CCC dos índices quantificados diante de uma diminuição dos valores nominais de preenchimento. Os métodos D e E apresentaram os máximos valores de CCC na avaliação do núcleo caudado _ 0,89 baixo MRI CA CCC ? e _ 0,84 baixo CT CA CCC ? ) e putâmen ( _ 0,86 baixo MRI PU CCC ? e _ 0,82 baixo CT PU CCC ? ). Entretanto, na avaliação do corpo estriado, o método B apresentou a máxima acurácia dentre os cinco aplicados ( _ 0,95 baixo TWOBOX ST CCC ? ). A significante correlação entre os métodos foi evidenciada por um elevado coeficiente de correlação (r > 0.8). Na avaliação da reprodutibilidade intra e interobservadores uma grande variabilidade foi observada na aplicação do método A, principalmente quando aplicada na semiquantificação de baixas concentrações de atividade. Conclusão: Os cinco métodos semiquantitativos de SPECT do corpo estriado, demonstraram ser eficientes na realização de leituras proporcionais dos índices de BPI mesmo quando aplicados a imagens de diferentes concentrações de atividade. Porém, diante de investigações que necessitem de um processo de quantificação mais acurado e visando avaliar putâmen e núcleo caudado de forma isolada, os métodos estruturais (MRI e CT), demonstraram uma crescente eficiência em representar acurados parâmetros semiquantitativos diante da diminuição dos índices nominais de preenchimento. Na investigação de todo o corpo estriado e carente de qualquer informação estrutural, o método TwoBox passa a ser recomendado devido sua melhor performance diante todos os métodos avaliados. / AIM: The molecular image of dopamine transporters (DAT) gives differential information in research of neurodegenerative diseases, such as Parkinson\'s, when properly approached quantitatively. Yet, each method used in clinical routine may give, or not, different results when the quantifications are applied in images of several activity levels. Hence, this study assessed the accuracy, precision and reproducibility of striatum SPECT images semi-quantification methods, based in ROIs. METHODOLOGY: Twenty-three SPECT images were acquisitions of anthropomorphic striatal phantom filled with different activity concentrations of 99mTc. For each acquisition performed, the specific chambers (caudate and putamen chambers) to large chamber (simulating nonspecific background activity) was filled with solutions activity of different specific to nonspecific ratios (10, 8, 6, 4 and 2 to 1). The images were reconstructed by iterative algorithm, corrected to attenuation effects and the extracted values were analyzed by the specific binding ratio (SBR). Five semi-quantification methods for striatum SPECT, using ROIs was assessment: (A) draw freehand ROIs on SPECT image (manual); standard size ROIs: (B) TwoBox and (C) ThreeBox Methods and VOIs using structural images: (D) MRI and (E) CT. Accuracy of methods applied was assessed by concordance correlation coefficient (CCC) and precision by Pearson\'s coefficient and linear regression. RESUlTS: The SBR quantified both to individual specific chambers and striatal chamber analyzed to all methods applied resulted in a CCC increase with decrease of the nominal values used. For lower SBR values, the D and E methods evidenced the maximum values of CCC in assessment of caudate (CCCMRI_CA = 0.89 e CCCCT_CA = 0.84) and putamen (CCCMRI_PU = 0.86 e CCCCT_PU = 0.82). However, striatal assessments the B method highlights a maximum accuracy between all methods applied (CCCTWOBOX_ST = 0.95), for low values of SBR. A high Pearson\'s coefficient was found in the correlation between the all methods, report thereby a good precision between them (r > 0.8). The high ICC and variability values, showed a high reprodutibility intra- and interobserver for B, C and D methods, white the A and E methods presented a high variability between the raters. CONCLUSION: The five semi-quantification methods of striatum SPECT reported a high precision even when applied in images with activity solutions different. Therefore, to research much accurate and need to assessment just caudate or putamen individually the structural methods - MRI and CT - demonstrated progressive improvement in its quantification to reduction nominal fill index. To assessment striatal chamber and in the absence of structural information, the TwoBox method is advisable due to its excellent agreement with all nominal values when compared to the various semi-quantitative methods investigated. Keywords:

Estima-se que o número de exames diagnósticos em Medicina Nuclear cresça a uma taxa de 5% ao ano, ocasionando aumento das exposições de pacientes, familiares e meio ambiente às radiações ionizantes. O intuito dos guias de referência em exames diagnósticos (DRL) é a padronização das técnicas e a diminuição das exposições ao mínimo possível e estritamente necessárias para a realização do exame médico, todavia, a área de Medicina Nuclear brasileira não possui este tipo de guia, favorecendo o descontrole das exposições e incremento de riscos associados. O principal objetivo deste estudo foi a elaboração de um DRL para a área de Medicina Nuclear com base nos tipos de exames, atividades administradas, técnicas adotadas e parque de equipamentos disponíveis no país. Formulários foram enviados para todos os Serviços de Medicina Nuclear do Brasil - SMNs (~430) visando obter essas informações, bem como os tipos de ajustes das atividades de acordo com a idade e o peso corpóreo dos pacientes. Os dados foram analisados e como proposta de DRL, considerou-se o valor do percentil 75 (P75) da atividade máxima administrada em cada exame. Um total de 107 SMNs, representando 14 estados brasileiros e o Distrito Federal, responderam ao questionário. Dos 64 diferentes procedimentos diagnósticos analisados, as cintilografias óssea, renal e paratireoide são disponibilizadas em mais de 85% de todos os SMNs analisados. As atividades administradas para um mesmo tipo de exame apresentaram uma alta taxa de dispersão, alcançando diferenças superiores a 20 vezes entre o menor e maior valor praticado. Exames diagnósticos envolvendo os radioisótopos 67Ga, 201Tl e 131I foram observados como os geradores de maior dose de radiação aos pacientes. O ajuste das atividades para pacientes pediátricos tem levado em consideração a regra de Webster, regra de três simples e ajustes empíricos de acordo com o peso corpóreo dos pacientes. Com a aplicação dos valores de atividade propostos como DRL na rotina clínica, pode-se alcançar uma redução mínima de 15%, máxima de 95% e média de 50% em relação às atividades atualmente aplicadas. Ao todo, foram encontrados 189 equipamentos de imagem em funcionamento, sendo principalmente de quatro fabricantes diferentes (Elscint, GE, Philips e Siemens). A variabilidade das atividades administradas para um mesmo tipo de exame, respeitando as diferenças tecnológicas, pode refletir a falta de controle das exposições à radiação e a inexistência de um guia de referência nacional para a área de Medicina Nuclear, assim como também exemplificar a diversidade de protocolos de imagem praticados no país. A adoção de um DRL para a área de Medicina Nuclear poderia contribuir consideravelmente para o controle das exposições e padronização da técnica, ofertando à população exames de alta tecnologia e de riscos controlados / It has been estimated that the number of diagnostic procedures in Nuclear Medicine has shown an annual growth rate of 5%, and consequently increasing the ionizing radiation exposition of patients, family and environment. The aim of diagnostic reference levels (DRL) is the standardization of techniques and decrease expositions to as low as possible and just compatible with the diagnostic exam under study. However, Brazilian Nuclear Medicine does not have those references, causing a decontrol of expositions and increasing the associated risks. The main objective of this study was the DRL development to Nuclear Medicine on the basis of diagnostic procedures, administered activities, adopted techniques, and the available equipments in the country. Forms were sent to all the Brazilian Nuclear Medicine Services -NMS (~430) aiming to obtain those information, as well as the rules applied to adjust the administered activities according to patient\'s age and body mass. All data were analyzed, and the percentile 75 (P75) of the maximum activity applied in each diagnostic exam was considered as the DRL. A total of 107 NMS have answered the form, representing 14 Brazilian states and Federal District. From the 64 diagnostic procedures studied, bone, kidney and parathyroid scintigraphy were found to be used in more than 85% of all the NMS analyzed. There was a large disparity among the activities administered, when applying the same procedure, reaching, in some cases, more than 20 times between the lowest and highest. Diagnostic exams based on 67Ga, 201Tl, and 131I radioisotopes proved to be de major exams administering radiation doses to patients. The activities adjustment to pediatric patients has used different rules, including Webster rule, rule of three and empirical adjustments according to the patient\'s body weight. On introducing the DRL activity values into clinical routine, the minimum reduction in radiation doses received by patients was about 15%, the maximum was 95%, and the average was 50% compared with the previously reported administered activities. There were found 189 image equipments working, with mainly 4 different brands (Elscint, GE, Philips e Siemens). The variability in the administered activities to the same diagnostic procedure, respecting the existing differences in technology, may reflect the lack of radiation exposition control and the non-existence of a national reference guide to Nuclear Medicine, as well as exemplify the variability in the image protocols practiced in the country. The establishment of DRL to a Nuclear Medicine could considerably contribute toward the control and reduction of radiation exposure, thereby offering to the public high-technology exams with controlled risks

OBJETIVO: A imagem molecular de transportadores de dopamina (DAT) oferecer uma informação diferencial na investigação de doenças neurodegenerativas, como a Doença de Parkinson, diante de uma sólida abordagem quantitativa. Porém, são diversos o número de diferentes métodos semiquantitativos aplicados na prática clínica, que nos quais podem produzir resultados distintos quando aplicados por diferentes avaliadores ou condições de avaliação da imagem de SPECT do corpo estriado. Logo, este estudo pode avaliar a acurácia, precisão e reprodutibilidade de diferentes métodos semiquantitativos de imagens de SPECT do corpo estriado. MATERIAIS E MÉTODOS: Foram realizadas 23 aquisições de SPECT utilizando um simulador antropomórfico estriatal preenchido com diferentes concentrações de atividade de 99mTc. A preparação deste simulador estriatal foi realizada a partir de concentrações de atividades nas cavidades de interesse (núcleo caudado, putâmen e corpo estriado) proporcionalmente maiores do que a da cavidade de referência (background). As imagens foram reconstruídas utilizando parâmetros ideais já protocolados. Cinco métodos baseados em ROIs, dedicados para a quantificação de SPECT do corpo estriado foram avaliados: ROIs desenhadas sobre as imagens de SPECT - (A) Manual, ROIs com dimensões padronizadas - (B) método Twobox e (C) método Threebox; e baseado em imagens estruturais (D) MRI e (E) CT. A acurácia de cada método aplicado foi avaliada através do coeficiente de correlação de concordância (CCC), sua precisão utilizando o coeficiente de Pearson e modelos regressão linear, assim como a reprodutibilidade pode ser investigada através de análises de variabilidade intra- e interobservadores. RESULTADOS: Tanto para as cavidades avaliadas de forma individual (Caudado e Putâmen), quanto para o corpo estriado como um todo, todos os métodos aplicados apresentaram um aumento no CCC dos índices quantificados diante de uma diminuição dos valores nominais de preenchimento. Os métodos D e E apresentaram os máximos valores de CCC na avaliação do núcleo caudado _ 0,89 baixo MRI CA CCC ? e _ 0,84 baixo CT CA CCC ? ) e putâmen ( _ 0,86 baixo MRI PU CCC ? e _ 0,82 baixo CT PU CCC ? ). Entretanto, na avaliação do corpo estriado, o método B apresentou a máxima acurácia dentre os cinco aplicados ( _ 0,95 baixo TWOBOX ST CCC ? ). A significante correlação entre os métodos foi evidenciada por um elevado coeficiente de correlação (r > 0.8). Na avaliação da reprodutibilidade intra e interobservadores uma grande variabilidade foi observada na aplicação do método A, principalmente quando aplicada na semiquantificação de baixas concentrações de atividade. Conclusão: Os cinco métodos semiquantitativos de SPECT do corpo estriado, demonstraram ser eficientes na realização de leituras proporcionais dos índices de BPI mesmo quando aplicados a imagens de diferentes concentrações de atividade. Porém, diante de investigações que necessitem de um processo de quantificação mais acurado e visando avaliar putâmen e núcleo caudado de forma isolada, os métodos estruturais (MRI e CT), demonstraram uma crescente eficiência em representar acurados parâmetros semiquantitativos diante da diminuição dos índices nominais de preenchimento. Na investigação de todo o corpo estriado e carente de qualquer informação estrutural, o método TwoBox passa a ser recomendado devido sua melhor performance diante todos os métodos avaliados. / AIM: The molecular image of dopamine transporters (DAT) gives differential information in research of neurodegenerative diseases, such as Parkinson\'s, when properly approached quantitatively. Yet, each method used in clinical routine may give, or not, different results when the quantifications are applied in images of several activity levels. Hence, this study assessed the accuracy, precision and reproducibility of striatum SPECT images semi-quantification methods, based in ROIs. METHODOLOGY: Twenty-three SPECT images were acquisitions of anthropomorphic striatal phantom filled with different activity concentrations of 99mTc. For each acquisition performed, the specific chambers (caudate and putamen chambers) to large chamber (simulating nonspecific background activity) was filled with solutions activity of different specific to nonspecific ratios (10, 8, 6, 4 and 2 to 1). The images were reconstructed by iterative algorithm, corrected to attenuation effects and the extracted values were analyzed by the specific binding ratio (SBR). Five semi-quantification methods for striatum SPECT, using ROIs was assessment: (A) draw freehand ROIs on SPECT image (manual); standard size ROIs: (B) TwoBox and (C) ThreeBox Methods and VOIs using structural images: (D) MRI and (E) CT. Accuracy of methods applied was assessed by concordance correlation coefficient (CCC) and precision by Pearson\'s coefficient and linear regression. RESUlTS: The SBR quantified both to individual specific chambers and striatal chamber analyzed to all methods applied resulted in a CCC increase with decrease of the nominal values used. For lower SBR values, the D and E methods evidenced the maximum values of CCC in assessment of caudate (CCCMRI_CA = 0.89 e CCCCT_CA = 0.84) and putamen (CCCMRI_PU = 0.86 e CCCCT_PU = 0.82). However, striatal assessments the B method highlights a maximum accuracy between all methods applied (CCCTWOBOX_ST = 0.95), for low values of SBR. A high Pearson\'s coefficient was found in the correlation between the all methods, report thereby a good precision between them (r > 0.8). The high ICC and variability values, showed a high reprodutibility intra- and interobserver for B, C and D methods, white the A and E methods presented a high variability between the raters. CONCLUSION: The five semi-quantification methods of striatum SPECT reported a high precision even when applied in images with activity solutions different. Therefore, to research much accurate and need to assessment just caudate or putamen individually the structural methods - MRI and CT - demonstrated progressive improvement in its quantification to reduction nominal fill index. To assessment striatal chamber and in the absence of structural information, the TwoBox method is advisable due to its excellent agreement with all nominal values when compared to the various semi-quantitative methods investigated. Keywords:

Os distúrbios da articulação temporomandibulares (DTM) apresentam um impacto negativo na qualidade de vida de seus portadores. A diversidade de sinais e sintomas apresentados pelos pacientes, como dores musculares, cefaléias (difusa ou localizada), dores na região da articulação temporomandibular (ATM), limitações ou excessos de abertura da boca e ruídos articulares dificultam o diagnóstico clínico. Para isso, há necessidade de uma investigação clínica minuciosa e de exames complementares. Os exames radiográficos convencionais e tomografias mostram a anatomia da região sem demonstrar alterações funcionais locais. A técnica de imagens tomográficas em Medicina Nuclear, SPECT (Single Photon Emission Computed Tomography) com 99m Tc-MDP (radiofármaco composto de Tecnécio 99 metaestável e Metileno Difosfonato), demonstra o metabolismo da região, e associada à fusão de imagens co-registradas com a tomografia computadorizada (CT), permite a localização anatômica das alterações ósseas funcionais existentes nas estruturas envolvidas. É um exame com baixa dose de radiação que possibilita a observação conjunta estrutural anatômica e metabólica. Neste trabalho avaliamos, retrospectivamente, exames SPECT/CT de 33 pacientes realizados no Setor de Medicina Nuclear do Departamento de Imagem do Centro de Tratamento e Pesquisa - Hospital do Câncer A. C. Camargo, que apresentavam sinais e sintomas de provável DTM. Os resultados dos exames foram relacionados aos dados existentes nos prontuários dos pacientes, como sexo, idade, anamnese e exame clínico. Por meio de análise descritiva, utilizando as freqüências e porcentagens das variáveis de interesse, pudemos avaliar a confiabilidade do exame. Concluímos que o SPECT/CT, quando aplicado em pacientes portadores de sinais e sintomas de DTM, apresentou alta sensibilidade (100%), especificidade (90,9%) e acurácia (96,9%), demonstrando que é um método de diagnóstico por imagem de relevância, útil e de grande valia, podendo ser um dos métodos de escolha indicados para diagnóstico de DTM. / Temporomandibular joint dysfunction play a negative role on patient life quality standard. A diversity of signs and symptoms such us muscular pain, headaches (focal or diffuse), temporomandibular joint localized pain, limitation or excessive mandibular opening and joint noise may lead to difficulties of correct diagnosis. Clinical investigation and complementary exams are necessary in these cases. Conventional radiographic and tomographic exams exactilly indicates local anatomy but do not demonstrate functional metabolic changes. Tomographic images on Nuclear Medicine, SPECT (Single Photon Emission Computed Tomography) with 99m Tc-MDP (methylene diphosphonate) a radiopharmaceutical labeled with Technetium 99m demonstrate regional metabolism changes. The association to co-registered computed tomography (CT) and image fusion allows the anatomic placement of bone functional alteration into the involved structures. SPECT/CT is a low dose radiation procedure that makes simultaneous anatomic and metabolic observation possible. This assignment was retrospectively analyzed, SPECT/CT of 33 patients from the Nuclear Medicine Sector of the Image Department of the Research and Treatment Center of the Cancer Hospital A. C. Camargo, that presented sings and symptoms of probable temporomandibular joint dysfunction. The results of the exams were related with the patient data that were on their file like sex, age, anamnesis and clinical exam. The assessment of the reliability of the exam was evaluated by descriptive analysis using frequencies and percentages of the interest variables. We conclude that SPEC/CT showed high sensitivity (100%), specificity (90,9%) and accuracy (96,9%); demonstrating that it is an important and useful diagnostic method, that may be an exam of choice to the diagnostic features of temporomandibular joint disfunction.

Os distúrbios da articulação temporomandibulares (DTM) apresentam um impacto negativo na qualidade de vida de seus portadores. A diversidade de sinais e sintomas apresentados pelos pacientes, como dores musculares, cefaléias (difusa ou localizada), dores na região da articulação temporomandibular (ATM), limitações ou excessos de abertura da boca e ruídos articulares dificultam o diagnóstico clínico. Para isso, há necessidade de uma investigação clínica minuciosa e de exames complementares. Os exames radiográficos convencionais e tomografias mostram a anatomia da região sem demonstrar alterações funcionais locais. A técnica de imagens tomográficas em Medicina Nuclear, SPECT (Single Photon Emission Computed Tomography) com 99m Tc-MDP (radiofármaco composto de Tecnécio 99 metaestável e Metileno Difosfonato), demonstra o metabolismo da região, e associada à fusão de imagens co-registradas com a tomografia computadorizada (CT), permite a localização anatômica das alterações ósseas funcionais existentes nas estruturas envolvidas. É um exame com baixa dose de radiação que possibilita a observação conjunta estrutural anatômica e metabólica. Neste trabalho avaliamos, retrospectivamente, exames SPECT/CT de 33 pacientes realizados no Setor de Medicina Nuclear do Departamento de Imagem do Centro de Tratamento e Pesquisa - Hospital do Câncer A. C. Camargo, que apresentavam sinais e sintomas de provável DTM. Os resultados dos exames foram relacionados aos dados existentes nos prontuários dos pacientes, como sexo, idade, anamnese e exame clínico. Por meio de análise descritiva, utilizando as freqüências e porcentagens das variáveis de interesse, pudemos avaliar a confiabilidade do exame. Concluímos que o SPECT/CT, quando aplicado em pacientes portadores de sinais e sintomas de DTM, apresentou alta sensibilidade (100%), especificidade (90,9%) e acurácia (96,9%), demonstrando que é um método de diagnóstico por imagem de relevância, útil e de grande valia, podendo ser um dos métodos de escolha indicados para diagnóstico de DTM. / Temporomandibular joint dysfunction play a negative role on patient life quality standard. A diversity of signs and symptoms such us muscular pain, headaches (focal or diffuse), temporomandibular joint localized pain, limitation or excessive mandibular opening and joint noise may lead to difficulties of correct diagnosis. Clinical investigation and complementary exams are necessary in these cases. Conventional radiographic and tomographic exams exactilly indicates local anatomy but do not demonstrate functional metabolic changes. Tomographic images on Nuclear Medicine, SPECT (Single Photon Emission Computed Tomography) with 99m Tc-MDP (methylene diphosphonate) a radiopharmaceutical labeled with Technetium 99m demonstrate regional metabolism changes. The association to co-registered computed tomography (CT) and image fusion allows the anatomic placement of bone functional alteration into the involved structures. SPECT/CT is a low dose radiation procedure that makes simultaneous anatomic and metabolic observation possible. This assignment was retrospectively analyzed, SPECT/CT of 33 patients from the Nuclear Medicine Sector of the Image Department of the Research and Treatment Center of the Cancer Hospital A. C. Camargo, that presented sings and symptoms of probable temporomandibular joint dysfunction. The results of the exams were related with the patient data that were on their file like sex, age, anamnesis and clinical exam. The assessment of the reliability of the exam was evaluated by descriptive analysis using frequencies and percentages of the interest variables. We conclude that SPEC/CT showed high sensitivity (100%), specificity (90,9%) and accuracy (96,9%); demonstrating that it is an important and useful diagnostic method, that may be an exam of choice to the diagnostic features of temporomandibular joint disfunction.

Background: Single photon emission computed tomography (SPECT) with dopamine transporter (DAT) and dopamine D2 receptor (D2R) ligands can visualise the integrity of the nigrostriatal dopamine system. Parkinson’s disease (PD) and the atypical parkinsonian diseases (APD), progressive supranuclear palsy (PSP) and multiple system atrophy (MSA), have similar symptoms and dopamine depletion, but differ in pharmacological response and prognosis. Clinical differentiation between PD and APD is often difficult in the early stages. The aims of the thesis were to evaluate the differential diagnostic and prognostic value of SPECT in early PD, MSA and PSP, to map the pattern of progression with dopamine SPECT, and map the pattern of dopamine SPECT in non-affected elderly volunteers with a prospective approach. Also, we evaluated the methodological aspects of dopamine SPECT with respect to image evaluation tools, reconstruction parameters and gamma cameras. Methods: 172 patients, included in an on-going clinical prospective study on idiopathic parkinsonism, participated in the SPECT study. Also, 31 age-matched healthy controls (HC) were followed within this study. SPECT was done with 123I-FP-Cit (DAT SPECT) and 123I-IBZM (D2R SPECT). Regions of interest (ROI) were used as a standard method for semi-quantitative image analysis. Results: SPECT uptake ratios from different gamma cameras could be equalised through correction equations derived from images of a brain-like phantom, provided that attenuation correction was applied. The ROI method had high reproducibility. SPECT uptake  in HC, measured with the ROI method and a volume based (VOI) method rendered similar trends, but gender and age differences in SPECT uptake were more marked with the VOI method, and less pronounced in DAT SPECT compared to D2R SPECT with both methods. The DAT SPECT uptake was significantly reduced in very early disease stage of PD and APD compared to HC. DATSPECT uptake was more reduced in PD with postural and gait disturbance (PIGD) compared to tremor-dominant PD. Decline in DAT SPECT uptake during the first year was more pronounced in PD and PSP compared to HC. D2R SPECT uptake overlapped between untreated PD and APD. After initiated treatment, the D2R SPECT uptake was significantly higher in MSA patients compared to PD, PSP and HC. Decline in D2R SPECT uptake during the first year was not significantly different between patients or compared to HC. Conclusions: 123I-FP-Cit SPECT is a valuable and sensitive method to detect early stage idiopathic parkinsonism. A different level of uptake between PIGD-PD compared to TD-PD indicates a prognostic potential. It is not possible to differ between PD, MSA and PSP in early stage with 123I-FP-Cit SPECT and no differential diagnostic value was found using 123I-IBZM SPECT in the early, untreated stage of PD, MSA and PSP. A different pattern of uptake of this ligand in MSA compared to PD and PSP during the first years of L-dopa treatment may, however, indicate a diagnostic value during the follow-up period.

The aim of this study is to optimise the acquisition and reconstruction for SPECT with 111In- pentetrotide with the iterative reconstruction software OSEMS. For 111In-pentetrotide SPECT, the uptake in the tumour is usually high compared to uptake in normal tissue. It may, however, be difficult to detect small tumours with the SPECT method because of high noise levels and the low spatial resolution. The liver is a common region for somatostatin-positive metastases, and to visually detect small tumours in the liver, as early as possible, is important for an effective treatment of the cancer disease. The study concentrates on the acquired number of projections, the subset size in the OSEM reconstruction and evaluates contrast as a function of noise for a range of OSEM iterations. The raw-data projections are produced using Monte Carlo simulations of an anthropomorphic phantom, including tumours in the liver. Two General Electric (GE) collimators are evaluated, the extended low-energy general-purpose (ELEGP) and the medium energy general-purpose (MEGP) collimator. Three main areas of reconstruction are investigated. First the reconstructions are performed for so called full time scans with the acquisition time used clinically. Also the effect of performing the examination in half-time or with half the injected activity is evaluated with the most optimal settings gained from the full time scans for both collimators. In addition images reconstructed without model-based compensation are also included for comparison. This study is a continuation of a previous study on 111In-pentetrotide SPECT where collimator choice and model-based compensation were evaluated for a cylindrical phantom representing small tumours in liver background. As in the previous study, ELEGP proved to be the better collimator. For ELEGP, the most optimal setting was 30 projection angles and a subset size of 6 projections in the OSEM reconstruction, and for MEGP optimal setting was 60 projections and 4 subsets. The difference between the different collimator settings were, however, rather small but proven significant. For both collimators the half-time scan including model-based compensation was better compared to the full-time reconstructions without model-based compensation.

The aim of this study is the development of a statistical denoising method, to reduce noise in scintigraphic images, preserving image quality characteristics such as contrast, and resolution. The method is based on principal component analysis (PCA) reduces the volume of image data, preserving a large amount of useful information, by considering that a small number of independent image components contain useful information (signal), whereas a large number of independent components contain statistical noise. Therefore, applying PCA and discarding the image components, which correspond to noise, noise reduction can be achieved. PCA is a multivariate correlation analysis technique which explains algebraically a variance-covariance structure of observed data sets with a few linear combinations of original variables [28-30]. The motivation behind PCA is to find a direction, or a few directions, that explain as much of the variability as possible. This is achieved because each direction is associated with a linear sum of the variables, which are linear sums of the initial variables. Thus, the first principal component is the linear sum corresponding to the direction of greatest variability. The search for the second principal component is restricted to variables that are uncorrelated with the first principal component. To assess the performance of the proposed denoising method was compared to four conventional noise reduction methods, employing quantitative image quality characteristics (noise and spatial resolution characteristics). Specifically, the linear filter (smooth 3x3 and smooth 5x5), and the non-linear filter (median 3x3 and median 5x5) were used. Additionally to demonstrate the applicability of the proposed method, it was applied to clinical planar scintigraphic images. / Ο όρος Πυρηνική Ιατρική περιγράφει τις διαγνωστικές και θεραπευτικές διαδικασίες, που απαιτούν την εισαγωγή ραδιοφαρμάκων στον οργανισμό. Οι απεικονιστικές τεχνικές της πυρηνικής ιατρικής αξιοποιούν το γεγονός ότι η ακτινοβολία των ραδιενεργών νουκλιδίων μπορεί να διαπεράσει τους ιστούς και να ανιχνευθεί εξωτερικά, καθιστώντας δυνατή τη μελέτη φυσιολογικών και βιοχημικών διαδικασιών εν εξελίξει σε ζωντανούς οργανισμούς. Η απεικόνιση πυρηνικής ιατρικής χρησιμοποιείται ευρέως στην κλινική πράξη. Σε σύγκριση με άλλες απεικονιστικές τεχνικές έχει το πλεονέκτημα ότι μπορεί να δώσει ταυτόχρονα ανατομικές και λειτουργικές πληροφορίες. Το μειονέκτημα όμως των εικόνων πυρηνικής ιατρικής είναι ο πολύ χαμηλός λόγος σήματος-προς-θόρυβο (signal-to-noise ratio-SNR) σε σχέση με εικόνες άλλων απεικονιστικών τεχνικών. Η εικόνα στην πυρηνική ιατρική αντιστοιχεί στην κατανομή ραδιενεργού υλικού μέσα στο σώμα του ασθενούς. Η τιμή κάθε pixel της εικόνας σχετίζεται με τον αριθμό των γ-φωτονίων που ανιχνεύονται σε μια περίοδο χρόνου. Οι τιμές αυτές ακολουθούν μια στατιστική κατανομή (κατανομή Poisson), λόγω της τυχαίας φύσης της διάσπασης του χορηγούμενου ραδιενεργού υλικού. Η διακύμανση μιας τυχαίας Poisson μεταβλητής ισούται με τη μέση τιμή της και συνεπώς για να μειωθεί η επίδραση του Poisson θορύβου, ο αριθμός των φωτονίων που ανιχνεύονται πρέπει να αυξηθεί. Αυτό μπορεί να επιτευχθεί με τρεις τρόπους. Πρώτον, με αύξηση του χρόνου καταγραφής, που συνεπάγεται όμως αυξημένο κίνδυνο μετακίνησης του ασθενή. Δεύτερον, με αύξηση της δόσης ραδιενεργού υλικού, που δίνεται στον ασθενή, κάτι που προφανώς είναι ανεπιθύμητο. Η τελευταία λύση είναι η χρήση γ-κάμερας με πολλαπλούς ανιχνευτές ή με πολύ ευαίσθητο ανιχνευτή, που συνεπάγεται αυξημένο κόστος και πολυπλοκότητα. Για το λόγο αυτό, τεχνικές ψηφιακής επεξεργασίας για μείωση θορύβου εικόνας μπορούν να συνεισφέρουν σημαντικά στη βελτίωση της εικόνας στην πυρηνική ιατρική. Οι κλασικές τεχνικές μείωσης θορύβου κάνουν χρήση γραμμικών φίλτρων εξομάλυνσης (smoothing filters) για την αντικατάσταση της τιμής κάθε εικονοστοιχείου (pixel) με μια μέση τιμή ,η οποία προκύπτει από τη γειτονιά του. Τα φίλτρα αυτά όμως έχουν το μειονέκτημα ότι μειώνουν την αντίθεση και τη διακριτική ικανότητα της εικόνας. Μη γραμμικά φίλτρα, όπως το median φίλτρο, διατηρούν σε πολλές περιπτώσεις την αντίθεση των δομών, αλλά επίσης υποβαθμίζουν την ποιότητα εικόνας. Ένας από τους λόγους, που οι συμβατικές τεχνικές δεν έχουν ικανοποιητικά αποτελέσματα είναι ότι δεν αντιμετωπίζουν το γεγονός ότι ο θόρυβος σε κάθε pixel εξαρτάται από την ένταση του σήματος (signal dependent noise). Για το λόγο αυτό έχουν προταθεί πρασαρμοζόμενα (adaptive) φίλτρα μείωσης θορύβου. Η κατηγορία των φίλτρων αυτών χρησιμοποιεί στατιστικά κριτήρια για την επιλογή των γειτονικών pixels, που χρησιμοποιούνται για τον υπολογισμό της τιμής του κεντρικού pixel. Στη συγκεκριμένη διπλωματική εργασία υλοποιήθηκε μέθοδος μείωσης θορύβου, που βασίζεται στη Ανάλυση Κύριων Συνιστωσών (Principal Components Analysis, PCA), προσαρμοσμένη σε εικόνες πυρηνικής ιατρικής. Η μέθοδος αυτή στοχεύει στη μείωση του κβαντικού θορύβου Poisson κατανομής, που εμπεριέχεται σε εικόνες πυρηνικής ιατρικής. Η PCA είναι μια στατιστική τεχνική, που εξετάζει τις σχέσεις που διέπουν τις μεταβλητές ενός συνόλου δεδομένων και βρίσκει ένα υποσύνολο από τις πιο σημαντικές μεταβλητές. Οι νέες μεταβλητές περιγράφονται σαν γραμμικός συνδυασμός των αρχικών μεταβλητών και κατατάσσονται σε σειρά σημαντικότητας σε σχέση με τη διακύμανση των δεδομένων που η κάθε μια εκφράζει. Η πρώτη σημαντική συνιστώσα (principal component) είναι η μεταβλητή που εκφράζει το μέγιστο ποσό διακύμανσης. Η δεύτερη σημαντική συνιστώσα εκφράζει το επόμενο μεγαλύτερο ποσό διακύμανσης και είναι ανεξάρτητη από της πρώτης κ.ο.κ.. Ουσιαστικά, το σύνολο των αρχικών σχετιζόμενων μεταβλητών μετασχηματίζεται σε ένα σύνολο ασυσχέτιστων μεταβλητών, όπου οι λιγότερο σημαντικές μεταβλητές μπορούν να απομακρυνθούν χωρίς ουσιαστική απώλεια πληροφορίας. Η κύρια χρήση της PCA είναι να μειωθεί ο όγκος ενός συνόλου δεδομένων και να οδηγηθούμε σε μια βέλτιστη περιγραφή τους. Στην περίπτωση των εικόνων πυρηνικής ιατρικής μπορούμε να θεωρήσουμε ότι λόγω του στατιστικού χαρακτήρα του θορύβου η χρήσιμη πληροφορία περιέχεται σε μικρό αριθμό συνιστωσών, ενώ ο θόρυβος σε ένα μεγάλο αριθμό μη-σημαντικών συνιστωσών. Εφαρμόζοντας συνεπώς την PCA και αφαιρώντας τις συνιστώσες που αντιστοιχούν στον θόρυβο μπορούμε να επιτύχουμε σημαντική μείωση του. Επίσης πραγματοποιήθηκε συγκριτική αξιολόγηση μεταξύ της προτεινόμενης μεθόδου και άλλων μεθόδων μείωσης θορύβου σε εικόνες πυρηνικής ιατρικής. Συγκεκριμένα, η μέθοδος που βασίζεται στη PCA συγκρίθηκε με το φίλτρο εξομάλυνσης (smooth 3x3 και smooth 5x5) και το μη-γραμμικό φίλτρο (median 3x3 και median 5x5). Όλες οι μέθοδοι εφαρμόστηκαν σε πρότυπες εικόνες πυρηνικής ιατρικής, που αποκτήθηκαν με τη βοήθεια δυο ομοιωμάτων, ενός ομοιώματος με μικρές θερμές περιοχές (hot spots phantom) και ενός ομοιώματος μέτρησης διακριτικής ικανότητας (bar phantom) σε διαφορετικούς χρόνους. Στις επεξεργασμένες εικόνες μετρήθηκαν ο θόρυβος, η αντίθεση, ο λόγος αντίθεσης-προς-θόρυβο (Contrast-to-Noise-ratio, CNR) και το εύρος στο ήμισυ της μέγιστης τιμής (Full-Width-of-Half-Maximum, FWHM). Τα αποτελέσματα της σύγκρισης έδειξαν ότι η μέθοδος που βασίζεται στη PCA μειώνει σημαντικά το θόρυβο, ενώ ταυτόχρονα αυξάνει το λόγο αντίθεσης-προς-θόρυβο. Τέλος, πραγματοποιήθηκε πιλοτική μελέτη προτίμησης από δυο πυρηνικούς ιατρούς μεταξύ των μεθόδων μείωσης θορύβου σε δείγμα κλινικών εικόνων συγκεκριμένων εξετάσεων στατικών λήψεων (οστών, πνευμόνων, θυρεοειδούς, παραθυρεοειδούς και νεφρών). Η μελέτη αυτή έδειξε ότι η PCA μειώνει σημαντικά το θόρυβο, ενώ ταυτόχρονα βελτιώνει οπτικά τις ανατομικές δομές των εικόνων.