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Quality control tests are mandatory and essential to monitor Magnetic Resonance Imaging equipment. These assist in determining improper functioning or parameters below established reference levels. The objective of this study was to perform quality control tests in magnetic resonance imaging equipment and to compare their methodology with both FLUKE and KONEX phantoms. Different protocols were used for their evaluation, including the American Association of Physics in Medicine, the American College of Radiologists, and the Brazilian National Health Surveillance Agency. In this study, we demonstrated the results for the most critical tests: slice thickness accuracy, slice position accuracy, high-contrast spatial resolution, low-contrast resolution, magnetic field, and slice thickness uniformity. The results are that, although both phantom objects are efficient for carrying out the tests required in Brazilian regulations, the KONEX phantom consumes less time, as it requires less to image all its structures. The FLUKE phantoms need a longer acquisition time to obtain all test structures and object images. Nevertheless, the results obtained in both are within limits required by Brazilian regulations and limits suggested by the manufacturers' manuals. This work is expected to be a basis for other physicians and services using similar phantoms.

Uma das maneiras de promover a otimização em proteção radiológica é implementando o conceito de Nível de Referência de Dose (DRL). Diversas são as formas de estimar a dose de radiação, dentre elas a estimativa do produto área-dose (DAP). Neste estudo, foi estimada a dose efetiva em exames radiológicos com o objetivo de determinar o DRL local. Para isso, os dados de DAP foram coletados e filtrados para o modelo de paciente padrão. Todos os procedimentos avaliados foram realizados em equipamentos de radiologia convencional com medidor de DAP embutido e devidamente calibrado, dentre eles: tórax anteroposterior (AP), tórax lateral (LAT) e tórax póstero-anterior (PA), abdômen AP, pelve AP e coluna lombar AP e LAT. O software PCXMC 2.0 foi empregado na simulação computacional de exames radiográficos para simular a dose efetiva no paciente para as incidências utilizadas. No total, após verificação dos dados, foram selecionados 167 valores de DAP e o número de incidências realizadas variou de 7 a 51 para diferentes projeções. A maior quantidade de incidências foi coletada para tórax LAT e a menor quantidade para coluna lombar LAT. Foram analisados 1º quartil, mediana e 3º quartil, bem como DAP mínimo e máximo e o valor interquartil (IQV) para cada conjunto de dados. As simulações computacionais resultaram em valores de dose efetiva compatíveis com a literatura. Por se tratar de um trabalho inicial, alguns pontos devem ser levados em consideração, como: o serviço faz parte de um hospital escola com profissionais em formação; existem cartas de técnicas disponíveis, porém os equipamentos digitais foram recém instalados; o estudo deve ser aprofundado, com número maior de incidências, para que os protocolos sejam bem estabelecidos no serviço. Este estudo serve de referência para outros serviços que desejam realizar o levantamento do nível de referência de diagnóstico para protocolos de radiologia convencional.

Made available in DSpace on 2022-04-29T08:31:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Introduction: Ionizing radiation-producing equipment is used in surgical centers to guide invasive procedures. Technological advances have enabled improvements in image quality, which may be accompanied by increased radiation doses in the surgical team. Correct use of personal protective equipment and monitoring of radiation levels are required to a safe practice. Objectives: To evaluate radiation exposure conditions in occupationally exposed persons working at the Surgical Center at Hospital das Clínicas da Faculdade de Medicina de Botucatu for implementation of radiation protection measures. Methods: Three different types of fluoroscopy equipment were used: C-arms, a dosimetric system with ionization chambers, and optically stimulated dosimeters. A three-stage evaluation was conducted, consisting of a first stage for observation, a second stage for estimation of kerma rate simulating exposure conditions, and a final stage for dosimetry to estimate the effective dose in workers. Results: The most frequent procedures and the disposition for each team member were determined. Kerma values were estimated for both the principal physician and the assistant physician. The maximum number of annual procedures was also estimated so that the dose limits are not exceeded. Conclusions: Dosimetry for the surgical team is indicated as an approach to monitor occupational dose levels. The dose rates and effective dose found in this study are low but not negligible. Thus, proper use of equipment and periodic training for workers are still the best options for radiation protection. Laboratório de Física Aplicada ao Radiodiagnóstico Faculdade de Medicina de Botucatu Universidade Estadual Paulista Núcleo de Física Médica e Radioproteção Hospital das Clínicas Faculdade de Medicina de Botucatu Universidade Estadual Paulista Serviço de Dosimetria Individual Sapra Landauer Departamento de Cirurgia e Ortopedia Hospital das Clínicas Faculdade de Medicina de Botucatu Universidade Estadual Paulista Hospital das Clínicas Faculdade de Medicina de Botucatu Universidade Estadual Paulista Setor Técnico de Medicina Nuclear Faculdade de Medicina de Botucatu Universidade Estadual Paulista Departamento de Infectologia Dermatologia Diagnóstico por Imagem e Radioterapia Faculdade de Medicina de Botucatu Universidade Estadual Paulista Laboratório de Física Aplicada ao Radiodiagnóstico Faculdade de Medicina de Botucatu Universidade Estadual Paulista Núcleo de Física Médica e Radioproteção Hospital das Clínicas Faculdade de Medicina de Botucatu Universidade Estadual Paulista Departamento de Cirurgia e Ortopedia Hospital das Clínicas Faculdade de Medicina de Botucatu Universidade Estadual Paulista Hospital das Clínicas Faculdade de Medicina de Botucatu Universidade Estadual Paulista Setor Técnico de Medicina Nuclear Faculdade de Medicina de Botucatu Universidade Estadual Paulista Departamento de Infectologia Dermatologia Diagnóstico por Imagem e Radioterapia Faculdade de Medicina de Botucatu Universidade Estadual Paulista

Made available in DSpace on 2022-04-29T08:29:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-06-01 In this work, we aimed to develop an automatic algorithm for the quantification of total volume and lung impairments in four different diseases. The quantification was completely automatic based upon high resolution computed tomography exams. The algorithm was capable of measuring volume and differentiating pulmonary involvement including inflammatory process and fibrosis, emphysema, and ground-glass opacities. The algorithm classifies the percentage of each pulmonary involvement when compared to the entire lung volume. Our algorithm was applied to four different patients groups: no lung disease patients, patients diagnosed with SARS-CoV-2, patients with chronic obstructive pulmonary disease, and patients with paracoccidioidomycosis. The quantification results were compared with a semi-automatic algorithm previously validated. Results confirmed that the automatic approach has a good agreement with the semi-automatic. Bland-Altman (B&A) demonstrated a low dispersion when comparing total lung volume, and also when comparing each lung impairment individually. Linear regression adjustment achieved an R value of 0.81 when comparing total lung volume between both methods. Our approach provides a reliable quantification process for physicians, thus impairments measurements contributes to support prognostic decisions in important lung diseases including the infection of SARS-CoV-2. Botucatu Medical School Clinics Hospital Medical Physics and Radioprotection Nucleus Institute of Bioscience Sao Paulo State University Julio de Mesquita Filho Radiology and Medical Imaging State University of Campinas Medical School Sao Paulo State University Julio de Mesquita Filho Botucatu Medical School Clinics Hospital Medical Physics and Radioprotection Nucleus Institute of Bioscience Sao Paulo State University Julio de Mesquita Filho Medical School Sao Paulo State University Julio de Mesquita Filho

Made available in DSpace on 2021-06-26T06:17:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-28 computed tomography service in Botucatu Medical School National Council for Scientific and Technological Development Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Background Platelet-rich plasma (PRP) has been used to favor anterior cruciate ligament (ACL) healing after reconstruction surgeries. However, clinical data are still inconclusive and subjective about PRP. Thus, we propose a quantitative method to demonstrate that PRP produced morphological structure changes. Methods Thirty-four patients undergoing ACL reconstruction surgery were evaluated and divided into control group (sixteen patients) without PRP application and experiment group (eighteen patients) with intraoperative application of PRP. Magnetic resonance imaging (MRI) scans were performed 3 months after surgery. We used Matlab (R) and machine learning (ML) in Orange Canvas (R) to texture analysis (TA) features extraction. Experienced radiologists delimited the regions of interest (RoIs) in the T2-weighted images. Sixty-two texture parameters were extracted, including gray-level co-occurrence matrix and gray level run length. We used the algorithms logistic regression (LR), naive Bayes (NB), and stochastic gradient descent (SGD). Results The accuracy of the classification with NB, LR, and SGD was 83.3%, 75%, 75%, respectively. For the area under the curve, NB, LR, and SGD presented values of 91.7%, 94.4%, 75%, respectively. In clinical evaluations, the groups show similar responses in terms of improvement in pain and increase in the IKDC index (International Knee Documentation Committee) and Lysholm score indices differing only in the assessment of flexion, which presents a significant difference for the group treated with PRP. Conclusions Here, we demonstrated quantitatively that patients who received PRP presented texture changes when compared to the control group. Thus, our findings suggest that PRP interferes with morphological parameters of the ACL. Sao Paulo State Univ Julio de Mesquita Filho, Med Sch, Av Prof Mario Rubens Guimaraes Montenegro S-N, BR-18618687 Botucatu, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Inst Biosci, R Prof Dr Antonio Celso Wagner Zanin 250, BR-18618687 Botucatu, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Med Sch, Av Prof Mario Rubens Guimaraes Montenegro S-N, BR-18618687 Botucatu, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Inst Biosci, R Prof Dr Antonio Celso Wagner Zanin 250, BR-18618687 Botucatu, SP, Brazil computed tomography service in Botucatu Medical School National Council for Scientific and Technological Development: PQ/CNPq 303509/2019-8 FAPESP: FAPESP 2020/05539-9

O objetivo deste trabalho foi desenvolver um indicador de dose eletrônico para a otimização da proteção radiológica no setor de Tomografia Computadorizada do Hospital das Clínicas de Botucatu. Foram estimadas doses efetivas utilizando o parâmetro DLP (do inglês Dose-Length Product). Estas doses efetivas foram comparadas com valores da literatura. O indicador de dose foi inserido no sistema de gestão hospitalar e contribuiu com o princípio da justificativa e proteção radiológica.Os valores de doses efetiva, para os protocolos da instituição são semelhantes aos referenciados na literatura, a maior diferença encontrada foi de 3,2%. O indicador de dose, carrega informações, sobre: a) dose acumulada pelo paciente em todos os exames de TC, b) O risco benefício de exames que envolvem radiação ionizante e c) Um termo que representa a ciência do solicitante quanto à dose acumulada e o risco-benefício.Este estudo vem corroborar com o princípio da justificação junto ao solicitante do exame. Essa ferramenta, contribui para orientação da equipe médica sobre a indicação excessiva de um exame considerado com alta taxa de dose. Essa metodologia pode ser implementada em qualquer serviço que realiza exames, envolvendo radiações ionizantes promovendo a melhor relação risco-benefício para o paciente custo-benefício para a instituição.

Made available in DSpace on 2021-06-25T10:35:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01. Added 1 bitstream(s) on 2021-07-15T15:22:47Z : No. of bitstreams: 1 S1678-91992020000100328.pdf: 2012220 bytes, checksum: 16ebe6eacc222cb008a8d097b95a7aa1 (MD5) American Federation for Aging Research Background: Neuroimaging strategies are essential to locate, to elucidate the etiology, and to the follow up of brain disease patients. Magnetic resonance imaging (MRI) provides good cerebral soft-tissue contrast detection and diagnostic sensitivity. Inflammatory lesions and tumors are common brain diseases that may present a similar pattern of a cerebral ring enhancing lesion on MRI, and non-enhancing core (which may reflect cystic components or necrosis) leading to misdiagnosis. Texture analysis (TA) and machine learning approaches are computer-aided diagnostic tools that can be used to assist radiologists in such decisions. Methods: In this study, we combined texture features with machine learning (ML) methods aiming to differentiate brain tumors from inflammatory lesions in magnetic resonance imaging. Retrospective examination of 67 patients, with a pattern of a cerebral ring enhancing lesion, 30 with inflammatory, and 37 with tumoral lesions were selected. Three different MRI sequences and textural features were extracted using gray level co-occurrence matrix and gray level run length. All diagnoses were confirmed by histopathology, laboratorial analysis or MRI. Results: The features extracted were processed for the application of ML methods that performed the classification. T1-weighted images proved to be the best sequence for classification, in which the differentiation between inflammatory and tumoral lesions presented high accuracy (0.827), area under ROC curve (0.906), precision (0.837), and recall (0.912). Conclusion: The algorithm obtained textures capable of differentiating brain tumors from inflammatory lesions, on T1-weghted images without contrast medium using the Random Forest machine learning classifier. Department of Physics and Biophysics Botucatu Biosciences Institute São Paulo State University (UNESP) Department of Radiology School of Medical Sciences University of Campinas (Unicamp) Department of Tropical Disease and Imaging Diagnosis Botucatu Medical School São Paulo State University (UNESP) Department of Physics and Biophysics Botucatu Biosciences Institute São Paulo State University (UNESP) Department of Tropical Disease and Imaging Diagnosis Botucatu Medical School São Paulo State University (UNESP)

Made available in DSpace on 2021-06-25T11:54:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-17 Evaluate whether texture analysis associated with machine learning approaches could differentiate between malignant and benign lymph nodes. A total 18 patients with lung cancer were selected, with 39 lymph nodes, being 15 malignant and 24 benign. Retrospective computed tomography scans were utilized both with and without contrast medium. The great differential of this work was the use of 15 textures from mediastinal lymph nodes, with five different physicians as operators. First and second order statistical textures such as gray level run length and co-occurrence matrix were extracted and applied to three different machine learning classifiers. The best machine learning classifier demonstrated a variability of less than 5% among operators. The support vector machine (SVM) classifier presented 95% of the area under the ROC curve (AUC) and 89% of sensitivity for sequences without contrast medium. SVM classifier presented 93% of AUC and 86% of sensitivity for sequences with contrast medium. Texture analysis and machine learning may be helpful in the differentiation between malign and benign lymph nodes. This study can aid the physician in diagnosis and staging of lymph nodes and potentially reduce the number of invasive analysis to histopathological confirmation. Sao Paulo State Univ Julio de Mesquita Filho, Med Sch, Aracatuba, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Inst Biosci, Aracatuba, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Med Sch, Aracatuba, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Inst Biosci, Aracatuba, Brazil

Made available in DSpace on 2018-12-11T17:19:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-09-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Objectives: In order to enable less experienced physicians to reliably detect early signs of stroke, A novel approach was proposed to enhance the visual perception of ischemic stroke in non-enhanced CT. Methods: A set of 39 retrospective CT scans were used, divided into 23 cases of acute ischemic stroke and 16 normal patients. Stroke cases were obtained within 4.5 h of symptom onset and with a mean NIHSS of 12.9±7.4. After selection of adjunct slices from the CT exam, image averaging was performed to reduce the noise and redundant information. This was followed by a variational decomposition model to keep the relevant component of the image. The expectation maximization method was applied to generate enhanced images. Results: We determined a test to evaluate the performance of observers in a clinical environment with and without the aid of enhanced images. The overall sensitivity of the observer’s analysis was 64.5 % and increased to 89.6 % and specificity was 83.3 % and increased to 91.7 %. Conclusion: These results show the importance of a computational tool to assist neuroradiology decisions, especially in critical situations such as the diagnosis of ischemic stroke. Key Points: • Diagnosing patients with stroke requires high efficiency to avoid irreversible cerebral damage. • A computational algorithm was proposed to enhance the visual perception of stroke. • Observers’ performance was increased with the aid of enhanced images. Instituto de Biociências de Botucatu Departamento de Física e Biofísica UNESP—Universidade Estadual Paulista, P.O. BOX 510, Distrito de Rubião Junior S/N Laboratory I3MTO – University of Orleans, 5 Rue de Chartres, BP 6744 Departamento de Neurologia Psicologia e Psiquiatria Faculdade de Medicina de Botucatu UNESP—Universidade Estadual Paulista, Distrito de Rubião Junior S/N Departamento de Diagnóstico por Imagem Escola Paulista de Medicina – UNIFESP, Rua Napoleão de Barros, 800 Departamento de Doenças Tropicais e Diagnóstico por Imagem Faculdade de Medicina de Botucatu UNESP—Universidade Estadual Paulista, Distrito de Rubião Junior S/N Instituto de Biociências de Botucatu Departamento de Física e Biofísica UNESP—Universidade Estadual Paulista, P.O. BOX 510, Distrito de Rubião Junior S/N Departamento de Neurologia Psicologia e Psiquiatria Faculdade de Medicina de Botucatu UNESP—Universidade Estadual Paulista, Distrito de Rubião Junior S/N Departamento de Doenças Tropicais e Diagnóstico por Imagem Faculdade de Medicina de Botucatu UNESP—Universidade Estadual Paulista, Distrito de Rubião Junior S/N FAPESP: 2014/22296-1

Este trabalho fez uso de revisão bibliográfica de guias, normas e legislação, nacionais e internacionais, para identificar as principais atribuições de especialistas em física médica e/ou supervisores de proteção radiológica que atuam em Serviços de Medicina Nuclear no Brasil. A partir do encontrado, foram propostos quatro eixos principais de atuação destes profissionais: Programa de Controle de Qualidade da Instrumentação, Programa de Monitoração Individual e Dosimetria, Gerência de Fontes, Materiais e Rejeitos Radioativos e Programa de Treinamento e Educação Continuada em Proteção Radiológica. Além disso, foram sinalizadas, também, atividades práticas pertinentes a cada eixo. Conclui-se que a atuação de físicos quando assumem a função de Supervisores de Proteção Radiológica na medicina nuclear vai muito além de testes de controle de qualidade de instrumentação. Estes profissionais devem estar inseridos em diversos fluxos, para que possam agir de maneira direta na manutenção de níveis elevados de segurança, eficiência e confiabilidade das práticas conduzidas, contribuindo para implementação de um Programa de Garantia de Qualidade abrangente e eficaz.

Background: The purpose of the present study was to evaluate differences in lung damage in patients with paracoccidioidomycosis (PCM) in two endemic regions of Brazil (Botucatu, SP, in the southeastern region and Campo Grande, MS, in the west central region). Methods: The study sought to objectively quantify fibrosis and emphysema treated patients using high-resolution computed tomography (HRCT) that was performed according to an established and validated computational method. The analysis was based on clinical data that were associated with objective quantifications of pulmonary sequelae. We performed a retrospective analysis of HRCT exams from 32 successfully treated patients with the chronic form of PCM. The two groups had similar characteristics with regard to age, symptom duration, smoking history, and titers on a diagnostic serologic test. Results: The statistical analysis revealed more severe cases and a higher percentage of emphysema in the Campo Grande group. The mean percentages of emphysema were 40.2% and 13.6% in the Campo Grande and Botucatu groups, respectively. The percentage of fibrosis was significantly higher in the Botucatu group (11.3%) than in the Campo Grande group (2.3%). Conclusions: The present results may reflect differences in cryptic species of P. brasiliensis in these two geographic regions of Brazil. Further studies should be done to clarify the differences observed herein. Such findings may help unveil differences among cryptic species in terms of the pulmonary consequences that are caused by this disease, which would be highly beneficial to PCM patients.

Made available in DSpace on 2019-10-06T16:42:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-07-01 Computed tomography (CT) has a high level of sensitivity and specificity for the diagnosis and follow-up of pathologies of the abdomen-pelvis region. Some features, such as automatic tube current modulation (ATCM), permits the acquisition of quality images with low radiation doses. This study evaluated the image quality and radiation dose of abdomen-pelvis CT protocols with ATCM technique. Were performed five CT protocols using 16-slice and 64-slice scanners, an anthropomorphic phantom for dosimetric measurements, an analytical phantom and retrospective examinations for image quality analysis. Were found significant reduction in effective dose. The highest absorbed doses were found in the stomach and spleen (56.1 and 47.2 mGy, respectively). Objective parameters as noise, low contrast and spatial resolution did not significantly differ between the protocols (p > 0.05). All protocols received the range of 'Optimum/Acceptable' in patient's image quality analysis. This methodology can be reproduced in any clinical routine to optimize CT protocols. São Paulo State University (UNESP) Instituto de Biociências de Botucatu Departamento de Física e Biofísica São Paulo State University (UNESP) Faculdade de Medicina de Botucatu Departamento de Doenças Tropicais e Diagnóstico Por Imagem Sapra Landauer, Rua Cid Silva César, 600 Universidade de São Paulo (USP) Faculdade de Filosofia Ciências e Letras de Ribeirão Preto Centro de Instrumentação Dosimetria e Radioproteção (CIDRA), Av. Bandeirantes, 3900 Bairro Monte Alegre São Paulo State University (UNESP) Instituto de Biociências de Botucatu Departamento de Física e Biofísica São Paulo State University (UNESP) Faculdade de Medicina de Botucatu Departamento de Doenças Tropicais e Diagnóstico Por Imagem

Made available in DSpace on 2019-10-04T12:35:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-02-14. Added 1 bitstream(s) on 2019-10-09T18:33:54Z : No. of bitstreams: 1 S1678-91992019000100302.pdf: 453940 bytes, checksum: cee89221ccadbf78dc3349dd3025432e (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) INCT-FNA Background: Tuberculosis (TB) is an infectious lung disease with high worldwide incidence that severely compromises the quality of life in affected individuals. Clinical tests are currently employed to monitor pulmonary status and treatment progression. The present study aimed to apply a three-dimensional (3D) reconstruction method based on chest radiography to quantify lung-involvement volume of TB acute-phase patients before and after treatment. In addition, these results were compared with indices from conventional clinical exams to show the coincidence level. Methods: A 3D lung reconstruction method using patient chest radiography was applied to quantify lung-involvement volume using retrospective examinations of 50 patients who were diagnosed with pulmonary TB and treated with two different drugs schemes. Twenty-five patients were treated with Scheme I (rifampicin, isoniazid, and pyrazinamide), whereas twenty-five patients were treated with Scheme II (rifampicin, isoniazid, pyrazinamide, and ethambutol). Acute-phase reaction: Serum exams included C-reactive protein levels, erythrocyte sedimentation rate, and albumin levels. Pulmonary function was tested posttreatment. Results: We found strong agreement between lung involvement and serum indices pre- and posttreatment. Comparison of the functional severity degree with lung involvement based on 3D image quantification for both treatment schemes found a high correlation. Conclusions: The present 3D reconstruction method produced a satisfactory agreement with the acute-phase reaction, most notably a higher significance level with the C-reactive protein. We also found a quite reasonable coincidence between the 3D reconstruction method and the degree of functional lung impairment posttreatment. The performance of the quantification method was satisfactory when comparing the two treatment schemes. Thus, the 3D reconstruction quantification method may be useful tools for monitoring TB treatment. The association with serum indices are not only inexpensive and sensitive but also may be incorporated into the assessment of patients during TB treatment. Univ Estadual Paulista, Inst Biociencias Botucatu, Dept Fis & Biofis, Botucatu, SP, Brazil Ctr Brasileiro Pesquisas Fis, Dept Altas Energias, Rio De Janeiro, RJ, Brazil Univ Estadual Paulista, Fac Med Botucatu, Dept Doencas Tropicais & Diagnost Imagem, Botucatu, SP, Brazil Univ Estadual Paulista, Inst Biociencias Botucatu, Dept Fis & Biofis, Botucatu, SP, Brazil Univ Estadual Paulista, Fac Med Botucatu, Dept Doencas Tropicais & Diagnost Imagem, Botucatu, SP, Brazil FAPESP: 2015/01948-3 CAPES: 3/2016 CAPES: 0722/2017 CAPES: 88881.142062/2017-01 CNPq: 18/2018 CNPq: 404770/2018-5

Made available in DSpace on 2018-12-11T17:06:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-08-01 Purpose To perform a complete evaluation on radiation doses, received by primary and assistant medical staff, while performing different vascular interventional radiology procedures. Materials and methods We evaluated dose received in different body regions during three categories of vascular procedures: lower limb angiography (Angiography), lower limb percutaneous transluminal angioplasty (Angioplasty) and stent graft placement for abdominal aortic aneurysm treatment (A. A. A. Treatment). We positioned the dosimeters near the eye lens, thyroid, chest, abdomen, hands, and feet of the interventional physicians. Equivalent dose was compared with annual dose limits for workers in order to determine the maximum number of procedures per year that each physician could perform. We assessed 90 procedures. Results We found the highest equivalent doses in the A. A. A. Treatment, in which 90% of the evaluations indicated at least one region receiving more than 1 mSv per procedure. Angioplasty was the only procedural modality that provided statistically different doses for different professionals, which is an important aspect on regards to radiological protection strategies. In comparison with the dose limits, the most critical region in all procedures was the eye lens. Conclusions Since each body region of the interventionist is exposed to different radiation levels, dose distribution measurements are essential for radiological protection strategies. These results indicate that dosimeters placed in abdomen instead of chest may represent more accurately the whole body doses received by the medical staff. Additional dosimeters and a stationary shield for the eye lens are strongly recommended. Instituto de Biociências de Botucatu Departamento de Física e Biofísica UNESP — Universidade Estadual Paulista, Distrito de Rubião Junior S/N Sapra Landauer, Rua Cid Silva César, 600 CIDRA – Centro de Instrumentação Dosimetria e Radioproteção Faculdade de Filosofia Ciências e Letras de Ribeirão Preto USP — Universidade de São Paulo, Av. Bandeirantes, 3900 Bairro Monte Alegre, Ribeirão Preto Departamento de Doenças Tropicais e Diagnóstico por Imagem Faculdade de Medicina de Botucatu UNESP — Universidade Estadual Paulista, Distrito de Rubião Junior S/N Instituto de Biociências de Botucatu Departamento de Física e Biofísica UNESP — Universidade Estadual Paulista, Distrito de Rubião Junior S/N Departamento de Doenças Tropicais e Diagnóstico por Imagem Faculdade de Medicina de Botucatu UNESP — Universidade Estadual Paulista, Distrito de Rubião Junior S/N

The objective of the present study was to optimize a radiographic technique for hand examinations using a computed radiography (CR) system and demonstrate the potential for dose reductions compared with clinically established technique. An exposure index was generated from the optimized technique to guide operators when imaging hands. Homogeneous and anthropomorphic phantoms that simulated a patient's hand were imaged using a CR system at various tube voltages and current settings (40–55 kVp, 1.25–2.8 mAs), including those used in clinical routines (50 kVp, 2.0 mAs) to obtain an optimized chart. The homogeneous phantom was used to assess objective parameters that are associated with image quality, including the signal difference-to-noise ratio (SdNR), which is used to define a figure of merit (FOM) in the optimization process. The anthropomorphic phantom was used to subjectively evaluate image quality using Visual Grading Analysis (VGA) that was performed by three experienced radiologists. The technique that had the best VGA score and highest FOM was considered the gold standard (GS) in the present study. Image quality, dose and the exposure index that are currently used in the clinical routine for hand examinations in our institution were compared with the GS technique. The effective dose reduction was 67.0%. Good image quality was obtained for both techniques, although the exposure indices were 1.60 and 2.39 for the GS and clinical routine, respectively.

Stroke is a cardio-vascular disease that currently ranks in the fifth position among all causes of death worldwide. Computed tomography is the first radiologic examination performed in emergency decisions to diagnose stroke. The earliest signs of ischemic stroke are quite subtle in CT, thus image-processing tools can be used to enhance ischemic areas and to aid physicians during diagnosis. This study aimed to enhance the ischemic stroke visual perception in computed tomography examinations. A cohort of 45 exams were used during this study, with 28 patients previously diagnosed with ischemic stroke and 17 control patients. Stroke cases were obtained within 4.5 h of symptom onset and with mean NIHSS of 13.6 ± 5.5. The complete series of non-enhanced images were obtained in DICOM format and all processing was performed in Matlab software R2017a. The main steps of the computed algorithm were as follows: an image averaging was performed to reduce the noise and redundant information within each slice; then a variational decomposition model was applied to keep the relevant component for our analysis; then three different segmentation methods were used to enhance the ischemic stroke area. The segmentation methods used were expectation maximization method, K-means and mean-shift. We determined a test to evaluate the performance of six observers (physicians) in a clinical environment with and without the aid of enhanced images. According to the opinion of the observers who participated in this study the enhanced images were particularly useful when displayed together with the original images. The overall sensitivity of the observer’s analysis changed after the evaluation of the enhanced images with the expectation maximization method. The overall specificity also increased. The improvement was even more remarkable for the three least experienced physicians.

Mammography is a worldwide image modality used to diagnose breast cancer and can be used to measure breast density (BD). In clinical routine, radiologist perform image evaluations through BIRADS assessment. However, this method has inter and intraindividual variability. An automatic method to measure BD could relieve radiologist’s workload by providing a first aid opinion. However, pectoral muscle (PM) is a high density tissue, with the same imaging characteristics as fibroglandular tissues, which makes its automatic detection a challenging task. The aim of this work is to develop an automatic algorithm to segment and extract PM in digital mammograms. A hybrid methodology has been developed using Hough transform, to find the edge of the PM, and active contour, to segment PM muscle. Seed of active contour is applied automatically in the edge of PM found by Hough transform. An experienced radiologist manually performed the PM segmentation. Manual and automatic methods were compared using the Jaccard index and Bland-Altman statistics. The comparison between methods presented a Jaccard similarity coefficient greater than 90% for all analyzed images. The Bland-Altman statistics compared the segmented PM area and showed agreement between both methods within 95% confidence interval. The method proved to be accurate and robust, segmenting rapid and free of intra and inter-observer variability.

Volumetric breast density has been shown to be one of the strongest risk factor for breast cancer diagnosis. This metric can be estimated using digital mammograms. During mammography acquisition, breast is compressed and part of it loses contact with the paddle, resulting in an uncompressed region in periphery with thickness variation. Therefore, reliable density estimation in the breast periphery region is a problem, which affects the accuracy of volumetric breast density measurement. The aim of this study was to enhance breast periphery to solve the problem of thickness variation. Herein, we present an automatic algorithm to correct breast periphery thickness without changing pixel value from internal breast region. The correction pixel values from periphery was based on mean values over iso-distance lines from the breast skin-line using only adipose tissue information. The algorithm detects automatically the periphery region where thickness should be corrected. A correction factor was applied in breast periphery image to enhance the region. We also compare our contribution with two other algorithms from state-of-the-art, and we show its accuracy by means of different quality measures. Experienced radiologists subjectively evaluated resulting images from the tree methods in relation to original mammogram. The mean pixel value, skewness and kurtosis from histogram of the three methods were used as comparison metric. As a result, the methodology presented herein showed to be a good approach to be performed before calculating volumetric breast density.

Objective: The objective of this study was to develop and validate a computational tool to assist radiological decisions on necrotizing enterocolitis. Methodology: Patients that exhibited clinical signs and radiographic evidence of Bell's stage 2 or higher were included in the study, resulting in 64 exams. The tool was used to classify localized bowel wall thickening and intestinal pneumatosis using full‐width at half‐maximum measurements and texture analyses based on wavelet energy decomposition. Radiological findings of suspicious bowel wall thickening and intestinal pneumatosis loops were confirmed by both patient surgery and histopathological analysis. Two experienced radiologists selected an involved bowel and a normal bowel in the same radiography. The full‐width at half‐maximum and wavelet‐based texture feature were then calculated and compared using the Mann–Whitney U test. Specificity, sensibility, positive and negative predictive values were calculated. Results: The full‐width at half‐maximum results were significantly different between normal and distended loops (median of 10.30 and 15.13, respectively). Horizontal, vertical, and diagonal wavelet energy measurements were evaluated at eight levels of decomposition. Levels 7 and 8 in the horizontal direction presented significant differences. For level 7, median was 0.034 and 0.088 for normal and intestinal pneumatosis groups, respectively, and for level 8 median was 0.19 and 0.34, respectively. Conclusions: The developed tool could detect differences in radiographic findings of bowel wall thickening and IP that are difficult to diagnose, demonstrating the its potential in clinical routine. The tool that was developed in the present study may help physicians to investigate suspicious bowel loops, thereby considerably improving diagnosis and clinical decisions. Resumo: Objetivo: O objetivo deste estudo foi desenvolver e validar uma ferramenta computacional para auxiliar as decisões radiológicas na enterocolite necrotizante. Metodologia: Pacientes que exibiam sinais clínicos e evidências radiográficas do estágio 2 ou superior de Bell foram incluídos no estudo, que resultou em 64 exames. A ferramenta foi usada para classificar o aumento localizado da espessura da parede intestinal e a pneumatose intestinal com medidas de largura total a meia altura e análises de textura baseadas na decomposição da energia wavelet. Os achados radiológicos de aumento suspeito da espessura da parede intestinal e das alças na pneumatose intestinal foram confirmados pela cirurgia e análise histopatológica do paciente. Dois radiologistas experientes selecionaram um intestino afetado e um intestino normal na mesma radiografia. A largura total a meia altura e a característica da textura baseada em wavelet foram então calculadas e comparadas com o uso do teste U de Mann‐Whitney. Foram calculados a especificidade, sensibilidade, valores preditivos positivos e negativos. Resultados: Os resultados da largura total a meia altura foram significativamente diferentes entre a alça normal e a distendida (mediana de 10,30 e 15,13, respectivamente). Medidas de energia wavelet horizontal, vertical e diagonal foram avaliadas em oito níveis de decomposição. Os níveis 7 e 8 na direção horizontal apresentaram diferenças significativas. Para o nível 7, as medianas foram 0,034 e 0,088 para os grupos normal e com pneumatose intestinal, respectivamente, e para o nível 8, as medianas foram 0,19 e 0,34, respectivamente. Conclusões: A ferramenta desenvolvida pode detectar diferenças nos achados radiográficos do aumento da espessura da parede intestinal e PI de difícil diagnóstico, demonstra seu potencial na rotina clínica. A ferramenta desenvolvida no presente estudo pode ajudar os médicos a investigar alças intestinais suspeitas e melhorar consideravelmente o diagnóstico e as decisões clínicas. Keywords: Necrotizing enterocolitis, Abdominal radiography, Image processing, Texture analyses, wavelet, Palavras‐chave: Enterocolite necrotizante, Radiografia abdominal, Processamento de imagem, Análises de textura, wavelet

Made available in DSpace on 2018-12-11T16:52:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 Background and objectives: Imaging exams play a key role in cochlear implants with regard to both planning implantation before surgery and quality control after surgery. The ability to visualize the three-dimensional location of implanted electrodes is useful in clinical routines for assessing patient outcome. The aim of this study was to evaluate linear and angular insertion depth measurements of cochlear implants based on conventional computed tomography. Methods: Tools for linear and angular measurements of cochlear implants were used in computed tomography exams. The tools realized the insertion measurements in an image reconstruction of the CIs, based on image processing techniques. We comprehensively characterized two cochlear implant models while obviating possible changes that can be caused by different cochlea sizes by using the same human temporal bones to evaluate the implant models. Results: The tools used herein were able to differentiate the insertion measurements between two cochlear implant models widely used in clinical practice. We observed significant differences between both insertion measurements because of their different design and construction characteristics (p = 0.004 and 0.003 for linear and angular measurements, respectively; t-test). The presented methodology showed to be a good tool to calculate insertion depth measurements, since it is easy to perform, produces high-resolution images, and is able to depict all the landmarks, thus enabling measurement of the angular and linear insertion depth of the most apical electrode contacts. Conclusion: The present study demonstrates practical and useful tools for evaluating cochlear implant electrodes in clinical practice. Further studies should measure preoperative and postoperative benefits in terms of speech recognition and evaluate the preservation of residual hearing in the implanted ear. Such studies can also determine correlations between surgical factors, electrode positions, and performance. In addition to refined surgical techniques, the precise evaluation of cochlear length and correct choice of cochlear implant characteristics can play an important role in postoperative outcomes. Instituto de Biociências de Botucatu Universidade Estadual Paulista (IBB-UNESP) Hospital de Clínicas Universidade Estadual de Campinas (HC-UNICAMP) Faculdade de Medicina de Botucatu Universidade Estadual Paulista (FMB-UNESP) Instituto de Biociências de Botucatu Universidade Estadual Paulista (IBB-UNESP) Faculdade de Medicina de Botucatu Universidade Estadual Paulista (FMB-UNESP)

This paper presents a novel framework devoted to the detection of HCC (Hepato-Cellular Carcinoma) within hepatic DCE-MRI (Dynamic Contrast-Enhanced MRI) sequences, by a deep learning approach. In clinical routine, radiologists usually consider different phases during contrast injection (before injection; arterial phase; portal phase for instance) for HCC diagnosis. By employing a U-Net architecture, we are able to identify such tumors with a very high accuracy (98.5% of classification rate at best) for a small cohort of patients, which should be confirmed in future works by considering larger groups. We also show in this paper the influence of patch size for this machine learning process, and the positive impact of employing all phases available in DCE-MRI sequences, compared to use only one.

Made available in DSpace on 2018-11-26T17:40:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-08-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Background: Mammography is a wordwild image modality used to diagnose breast cancer, even for asymptomatic women. Due to its large availability, mammograms can be used to measure breast density and to predict cancer development. Methods: We developed a methodology to estimate breast density using post-processed digital mammogram. Our automatic approach utilizes an optimized Fuzzy C-Means with variable compactness algorithm to classify and quantify fibroglandular tissue in mammograms. Results: Fibroglandular tissue percentage estimation by our method has been compared with BI-RADS assessment from radiologist and achieved 67.8% of correct classification, with Spearman's correlation coefficient of p = 0.618, for p < 0.001. Furthermore, a Bland Altman statistics showed no significant differences (bias of -0.20 +/- 1.52) between both methods, indicating that the assessment widely used in clinical routine is consistent with the results generated by the algorithms. Cohen's kappa coefficient comparing the performance of the algorithm with the visual assessment for the different BI-RADS scores was 0.47 suggesting a moderate agreement. Conclusion: Then, our methodology showed to be robust and accurate when compared with visual assessment. Furthermore, our methodology is fully automatic and reproducible, avoiding inter and intra observers variation, which has a potential to be implemented in clinical routine. (C) 2017 AGBM. Published by Elsevier Masson SAS. All rights reserved. Sao Paulo State Univ, Biosci Inst Botucatu, Dept Phys & Biophys, BR-18618000 Botucatu, SP, Brazil Univ Clermont Auvergne, Inst Pascal, CNRS, UMR 6602,SIGMA, F-63171 Aubiere, France Sao Paulo State Univ, Botucatu Med Sch, Dept Trop Dis & Diagnost Imaging, BR-18618000 Botucatu, SP, Brazil Sao Paulo State Univ, Biosci Inst Botucatu, Dept Phys & Biophys, BR-18618000 Botucatu, SP, Brazil Sao Paulo State Univ, Botucatu Med Sch, Dept Trop Dis & Diagnost Imaging, BR-18618000 Botucatu, SP, Brazil CAPES: 88881.132793/2016-01

Made available in DSpace on 2018-12-11T17:11:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01 Purpose The aim of the present study was to determine the efficiency of six methods for calculate the effective dose (E) that is received by health professionals during vascular interventional procedures. Methods We evaluated the efficiency of six methods that are currently used to estimate professionals’ E, based on national and international recommendations for interventional radiology. Equivalent doses on the head, neck, chest, abdomen, feet, and hands of seven professionals were monitored during 50 vascular interventional radiology procedures. Professionals’ E was calculated for each procedure according to six methods that are commonly employed internationally. To determine the best method, a more efficient E calculation method was used to determine the reference value (reference E) for comparison. Results The highest equivalent dose were found for the hands (0.34 ± 0.93 mSv). The two methods that are described by Brazilian regulations overestimated E by approximately 100% and 200%. The more efficient method was the one that is recommended by the United States National Council on Radiological Protection and Measurements (NCRP). The mean and median differences of this method relative to reference E were close to 0%, and its standard deviation was the lowest among the six methods. Conclusions The present study showed that the most precise method was the one that is recommended by the NCRP, which uses two dosimeters (one over and one under protective aprons). The use of methods that employ at least two dosimeters are more efficient and provide better information regarding estimates of E and doses for shielded and unshielded regions. São Paulo State University (UNESP) Instituto de Biociências de Botucatu Departamento de Física e Biofísica Sapra Landauer, Rua Cid Silva César, 600 Universidade de São Paulo (USP) Faculdade de Filosofia Ciências e Letras de Ribeirão Preto Centro de Instrumentação Dosimetria e Radioproteção (CIDRA), Av. Bandeirantes, 3900 Bairro Monte Alegre São Paulo State University (UNESP) Faculdade de Medicina de Botucatu Departamento de Neurologia, Psicologia e Psiquiatria Consult, Rua Sinharinha Frota, 1064 São Paulo State University (UNESP) Faculdade de Medicina de Botucatu Departamento de Doenças Tropicais e Diagnóstico por Imagem São Paulo State University (UNESP) Instituto de Biociências de Botucatu Departamento de Física e Biofísica São Paulo State University (UNESP) Faculdade de Medicina de Botucatu Departamento de Neurologia, Psicologia e Psiquiatria São Paulo State University (UNESP) Faculdade de Medicina de Botucatu Departamento de Doenças Tropicais e Diagnóstico por Imagem

Made available in DSpace on 2018-11-26T17:34:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) We describe the development of a joint in vivo/ex vivo protocol to monitor magnetic nanoparticles in animal models. Alternating current biosusceptometry (ACB) enables the assessment of magnetic nanoparticle accumulation, followed by quantitative analysis of concentrations in organs of interest. We present a study of real-time liver accumulation, followed by the assessment of sequential biodistribution using the same technique. For quantification, we validated our results by comparing all of the data with electron spin resonance (ESR). The ACB had viable temporal resolution and accuracy to differentiate temporal parameters of liver accumulation, caused by vasculature extravasation and macrophages action. The biodistribution experiment showed different uptake profiles for different doses and injection protocols. Comparisons with the ESR system indicated a correlation index of 0.993. We present the ACB system as an accessible and versatile tool to monitor magnetic nanoparticles, allowing in vivo and real-time evaluations of distribution and quantitative assessments of particle concentrations. (C) 2017 Elsevier Inc. All rights reserved. Univ Estadual Paulista, Dept Fis & Biofis, Lab Biomagnetismo, IBB, Botucatu, SP, Brazil Univ Fed Goias, Inst Fis, Goiania, Go, Brazil Univ Texas MD Anderson Canc Ctr, Dept Expt Radiat Oncol, Houston, TX 77030 USA Univ Estadual Paulista, Fac Med Botucatu, Dept Doencas Trop & Diagnost Imagem, Botucatu, SP, Brazil Univ Sao Paulo, Fac Med Ribeirao Preto, Ribeirao Preto, SP, Brazil Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Fis, Ribeirao Preto, SP, Brazil Univ Estadual Paulista, Dept Fis & Biofis, Lab Biomagnetismo, IBB, Botucatu, SP, Brazil Univ Estadual Paulista, Fac Med Botucatu, Dept Doencas Trop & Diagnost Imagem, Botucatu, SP, Brazil FAPESP: 2010/07639-9 FAPESP: 2011/18696-6 FAPESP: 2013/20842-6 FAPESP: 2015/14914-0

Made available in DSpace on 2018-11-26T16:19:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Purpose: The purpose of this study was to develop a methodology to optimize computed radiographic techniques to image the skull, chest, and pelvis of a standard patient. Methods: Optimization was performed by varying exposure levels with different tube voltages to generate images of an anthropomorphic phantom. Image quality was evaluated using visual grading analysis and measuring objective parameters such as the effective detective quantum efficiency and the contrast-to-noise ratio. Objective and subjective evaluations were compared to obtain an optimized technique for each anatomic region. Results: Gold standard techniques provided a significant reduction in X-ray doses compared to the techniques used in our radiology service, without compromising diagnostic accuracy. They were chosen as follows 102 kVp/1.6 mAs for skull; 81 kVp/4.5 mAs for pelvis and 90 kVp/3.2 mAs for chest. Conclusion: There is a range of acceptable techniques that produce adequate images for diagnosis in computed radiography systems. This aspect allows the optimization process to be focused on the patient dose without compromising diagnostic capabilities. This process should be performed through association of quantitative and qualitative parameters, such as effective detective quantum efficiency, contrast-to-noise ratio, and visual grading analysis. (C) 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved. Sao Paulo State Univ, Biosci Inst Botucatu, Dept Phys & Biophys, Dist Rubiao Jr S-N, BR-18618000 Botucatu, SP, Brazil Sao Paulo State Univ, Botucatu Med Sch, Dept Trop Dis & Diagnost Imaging, Distrito Rubiao Jr S-N, BR-18618000 Botucatu, SP, Brazil Brazilian Ctr Phys Res CBPF MCT, Dr Xavier Sigaud 150, BR-22290180 Rio De Janeiro, Brazil Sao Paulo State Univ, Biosci Inst Botucatu, Dept Phys & Biophys, Dist Rubiao Jr S-N, BR-18618000 Botucatu, SP, Brazil Sao Paulo State Univ, Botucatu Med Sch, Dept Trop Dis & Diagnost Imaging, Distrito Rubiao Jr S-N, BR-18618000 Botucatu, SP, Brazil

The main goal of this work was to develop a methodology for the computed analysis of American College of Radiology (ACR) mammographic phantom images, to be used in a quality control (QC) program of mammographic services. Discrete wavelet transform processing was applied to enhance the quality of images from the ACR mammographic phantom and to allow a lower dose for automatic evaluations of equipment performance in a QC program. Regions of interest (ROIs) containing phantom test objects (e.g., masses, fibers and specks) were focalized for appropriate wavelet processing, which highlighted the characteristics of structures present in each ROI. To minimize false-positive detection, each ROI in the image was submitted to pattern recognition tests, which identified structural details of the focalized test objects. Geometric and morphologic parameters of the processed test object images were used to quantify the final level of image quality. The final purpose of this work was to establish the main computational procedures for algorithms of quality evaluation of ACR phantom images. These procedures were implemented, and satisfactory agreement was obtained when the algorithm scores for image quality were compared with the results of assessments by three experienced radiologists. An exploratory study of a potential dose reduction was performed based on the radiologist scores and on the algorithm evaluation of images treated by wavelet processing. The results were comparable with both methods, although the algorithm had a tendency to provide a lower dose reduction than the evaluation by observers. Nevertheless, the objective and more precise criteria used by the algorithm to score image quality gave the computational result a higher degree of confidence. The developed algorithm demonstrates the potential use of the wavelet image processing approach for objectively evaluating the mammographic image quality level in routine QC tests. The implemented computational procedures could also enable the performance of advanced analyses to study potential dose reduction in a routine service.

Purpose: The main purpose of the present study was to determine the amounts of different tissues in the chest of the newborn patient (age {

OBJETIVO: Avaliação de condições dos equipamentos e dosimetria em setores de tomografia computadorizada utilizando protocolos de cabeça, abdome e coluna lombar em pacientes adultos (em três equipamentos distintos) e pediátricos com até um ano e meio de vida (em um dos equipamentos avaliados). MATERIAIS E MÉTODOS: Foram estimados o índice de dose em tomografia computadorizada e a dose média em cortes múltiplos, em exames com pacientes adultos, em três distintos equipamentos. Ainda foram estimadas as doses na superfície de entrada e as doses absorvidas em exame de cabeça para pacientes adultos e pediátricos em um dos equipamentos avaliados. RESULTADOS: Foram realizados testes de controle de qualidade, mecânicos, demonstrando que os equipamentos satisfazem as especificações de uso estabelecidas pelas normas vigentes. Os resultados da dosimetria mostraram que valores de dose média em cortes múltiplos excederam em até 109,0% os valores de níveis de referência, apresentando consideráveis variações entre os equipamentos avaliados neste estudo. As doses absorvidas obtidas com protocolos pediátricos são inferiores aos de pacientes adultos, apresentando redução de até 51,0% na tireoide. CONCLUSÃO: Neste estudo foram avaliadas as condições de operação de três equipamentos tomográficos, estabelecendo quais parâmetros devem ser trabalhados para a implantação de um programa de controle de qualidade nas instituições onde esta pesquisa foi desenvolvida.OBJECTIVE: Evaluation of equipment conditions and dosimetry in computed tomography services utilizing protocols for head, abdomen, and lumbar spine in adult patients (in three different units) and pediatric patients up to 18 months of age (in one of the units evaluated). MATERIALS AND METHODS: Computed tomography dose index and multiple-scan average dose were estimated in studies of adult patients with three different units. Additionally, entrance surface doses as well as absorbed dose were estimated in head studies for both adult and pediatric patients in a single computed tomography unit. RESULTS: Mechanical quality control tests were performed, demonstrating that computed tomography units comply with the equipment-use specifications established by the current standards. Dosimetry results have demonstrated that the multiple-scan average dose values were in excess of up to 109.0% the reference levels, presenting considerable variation amongst the computed tomography units evaluated in the present study. Absorbed doses obtained with pediatric protocols are lower than those with adult patients, presenting a reduction of up to 51.0% in the thyroid gland. CONCLUSION: The present study has analyzed the operational conditions of three computed tomography units, establishing which parameters should be set for the deployment of a quality control program in the institutions where this study was developed.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:48:20Z No. of bitstreams: 1 S0100-39842009000300010.pdf: 222417 bytes, checksum: 291c73f277f9c0544f35f2e041a7ebac (MD5) Made available in DSpace on 2013-08-22T18:48:20Z (GMT). No. of bitstreams: 1 S0100-39842009000300010.pdf: 222417 bytes, checksum: 291c73f277f9c0544f35f2e041a7ebac (MD5) Previous issue date: 2009-06-01 Made available in DSpace on 2013-09-30T18:17:30Z (GMT). No. of bitstreams: 2 S0100-39842009000300010.pdf: 222417 bytes, checksum: 291c73f277f9c0544f35f2e041a7ebac (MD5) S0100-39842009000300010.pdf.txt: 32147 bytes, checksum: eebfdbf7a7e13ebd7bf3ee7534f71d31 (MD5) Previous issue date: 2009-06-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:33:34Z No. of bitstreams: 2 S0100-39842009000300010.pdf: 222417 bytes, checksum: 291c73f277f9c0544f35f2e041a7ebac (MD5) S0100-39842009000300010.pdf.txt: 32147 bytes, checksum: eebfdbf7a7e13ebd7bf3ee7534f71d31 (MD5) Made available in DSpace on 2014-05-20T13:33:34Z (GMT). No. of bitstreams: 2 S0100-39842009000300010.pdf: 222417 bytes, checksum: 291c73f277f9c0544f35f2e041a7ebac (MD5) S0100-39842009000300010.pdf.txt: 32147 bytes, checksum: eebfdbf7a7e13ebd7bf3ee7534f71d31 (MD5) Previous issue date: 2009-06-01 OBJETIVO: Avaliação de condições dos equipamentos e dosimetria em setores de tomografia computadorizada utilizando protocolos de cabeça, abdome e coluna lombar em pacientes adultos (em três equipamentos distintos) e pediátricos com até um ano e meio de vida (em um dos equipamentos avaliados). MATERIAIS E MÉTODOS: Foram estimados o índice de dose em tomografia computadorizada e a dose média em cortes múltiplos, em exames com pacientes adultos, em três distintos equipamentos. Ainda foram estimadas as doses na superfície de entrada e as doses absorvidas em exame de cabeça para pacientes adultos e pediátricos em um dos equipamentos avaliados. RESULTADOS: Foram realizados testes de controle de qualidade, mecânicos, demonstrando que os equipamentos satisfazem as especificações de uso estabelecidas pelas normas vigentes. Os resultados da dosimetria mostraram que valores de dose média em cortes múltiplos excederam em até 109,0% os valores de níveis de referência, apresentando consideráveis variações entre os equipamentos avaliados neste estudo. As doses absorvidas obtidas com protocolos pediátricos são inferiores aos de pacientes adultos, apresentando redução de até 51,0% na tireoide. CONCLUSÃO: Neste estudo foram avaliadas as condições de operação de três equipamentos tomográficos, estabelecendo quais parâmetros devem ser trabalhados para a implantação de um programa de controle de qualidade nas instituições onde esta pesquisa foi desenvolvida. OBJECTIVE: Evaluation of equipment conditions and dosimetry in computed tomography services utilizing protocols for head, abdomen, and lumbar spine in adult patients (in three different units) and pediatric patients up to 18 months of age (in one of the units evaluated). MATERIALS and METHODS: Computed tomography dose index and multiple-scan average dose were estimated in studies of adult patients with three different units. Additionally, entrance surface doses as well as absorbed dose were estimated in head studies for both adult and pediatric patients in a single computed tomography unit. RESULTS: Mechanical quality control tests were performed, demonstrating that computed tomography units comply with the equipment-use specifications established by the current standards. Dosimetry results have demonstrated that the multiple-scan average dose values were in excess of up to 109.0% the reference levels, presenting considerable variation amongst the computed tomography units evaluated in the present study. Absorbed doses obtained with pediatric protocols are lower than those with adult patients, presenting a reduction of up to 51.0% in the thyroid gland. CONCLUSION: The present study has analyzed the operational conditions of three computed tomography units, establishing which parameters should be set for the deployment of a quality control program in the institutions where this study was developed. Universidade Estadual Paulista Faculdade de Medicina de Botucatu Centro Brasileiro e Pesquisas Físicas Universidade de São Paulo Faculdade de Medicina de Ribeirão Preto Hospital das Clínicas Universidade Estadual Paulista Faculdade de Medicina de Botucatu Hospital das Clínicas Universidade Estadual Paulista Instituto de Biociências de Botucatu Universidade Estadual Paulista Faculdade de Medicina de Botucatu Universidade Estadual Paulista Faculdade de Medicina de Botucatu Hospital das Clínicas Universidade Estadual Paulista Instituto de Biociências de Botucatu

Background This study proposes an experimental model to assess the consequences of gastric surgeries on gastric motility. We investigated the effects of proximal gastrectomy (PG) using a non-invasive technique (alternate current biosusceptometry [ACB]) on gastric contractility (GC), gastric emptying (GE), and orocecal transit (OCT) after the ingestion of liquids and solids in rats. Methods Twenty-four male rats were subjected to gastric motility assessment before and after the PG procedure. The GE and OCT results are expressed as the mean time of gastric emptying (MGET) and cecum arrival (MCAT). The GC recordings are presented as the frequency and amplitude of contractions. Key Results Mean time of gastric emptying after solid meals were significantly different (p

Pediatric patients are more radiosensitivity and have a longer life expectancy than adults, thus exposing them to a greater risk of developing cancer. The most appropriate radiographic technique for pediatric radiology involves the best relationship between radiological protection and the appropriate exposure in imaging detector. The aim of this study was to optimize pediatric radiographic techniques for skull and chest in the Agfa CR85-X system. The homogeneous pediatric phantoms, IC (infant chest) and IS (infant skull), were used to evaluate physical quantities such as effective detective quantum efficiency (eDQE). The choice of Gold Standard techniques was based upon comparison with a previous work, in which the optimization of adult techniques was realized. All Gold Standard techniques are according to the ALARA principle in which a sufficient image quality is associated with the lowest entrance skin dose possible.

This study presents the development of a homog-enous hand patient equivalent phantom (hPEP) to be used in an optimization process in computed radiography systems. Lucite and aluminum plates were used for hPEP construction and their thickness were determined by the equivalence of tissues from anthropomorphic phantom (2.5 cm and 0.2 cm respectively). This phantom was used in x-ray beam calibra-tion to obtain the test-techniques of the optimization process with Agfa® exposure index values between 1.8 and 2.0. These test-techniques were applied to an anthropomorphic phantom to the image quality optimization process. In this process the obtained images were assessed by three experienced radiolo-gists through visual grading analysis, and a gold standard (GS) technique was selected on the basis of image quality and As Low As Reasonable Achievable (ALARA) dose. Compared to the previously adopted technique for the clinical routine of the HCFMB-UNESP, the GS technique provided optimal image quality, with reductions in dose and tube load of 41.3% and 33.2%, respectively. The images generated by using GS tech-nique has satisfactory quality for a safe diagnosis, decreasing the radiation risk to the patient and increasing the lifetime of the x-ray tube.

Interventional Radiology is the radiology modality that provides the highest dose values to medical staff. Recent researches show that personal dosimeters may underestimate dose values in interventional physicians, especially in extremities and eye lens. The aim of this work was to study radiation exposure levels of medical staff in different hemodynamics interventional radiology procedures. Dosimeters were positioned in different body regions of the interventional physician. Dose values were compared with annual dose limits for workers thus finding the maximum number of annual procedures that each physician could perform. As each body region of the interventionist is subject to different levels of exposure, dose distribution in each region provides a better approach to what actions are necessary to ensure the radiological protection of medical staff.

Tuberculosis, caused by Mycobacterium tubercu-losis, is an infectious disease which remains a global health problem. The chest radiography is the common method employed to assess the tuberculosis evolution. Despite the tuberculosis diagnosis be normally realized by chest radiography analyses, the objective quantification of pulmonary diseases has been devel-oped with high resolution computed tomography scans. This quantification is important to assess evolution, treatment and comparison of different tuberculosis treatments. The aim of this work is to develop a methodology for pulmonary fibrosis quanti-fication caused by tuberculosis using chest radiographs. An algorithm was developed in Matlab® for computational pro-cessing of exams, which creates a lungs’ 3D representation with fibrosis regions. The developed method was performed with a group of 14 patients diagnosed with pulmonary Tuberculosis. For the same patients, the data were compared with quantifica-tion method of high resolution computed tomography scans, previously described in the literature. Statistical analysis was performed by linear regression and Bland-Altman plot. The results showed an average variation of 11.32% between the two quantification methods. The results suggest the effectiveness and applicability of the developed method, providing better risk-benefit to the patient and cost-benefit ratio for the institution.

OBJETIVO: Este trabalho tem como objetivo a otimização de imagens mamográficas, com consideráveis reduções de doses. MATERIAIS E MÉTODOS: Neste estudo o feixe de raios-X foi calibrado para cada tensão (kVp), de modo a determinar a melhor combinação de kVp e mAs que irá proporcionar uma densidade ótica (DO) em torno de 1.0 acima da base mais véu do filme utilizado. RESULTADOS: Serão discutidas questões sobre os métodos empregados para a seleção de parâmetros de exposição do feixe de raios-X, seleção da melhor imagem utilizando o método de avaliação gradativa visual, comparações entre as doses e carga do tubo (kVp × mAs) proporcionadas pelas técnicas determinadas neste estudo e pelas utilizadas na rotina clínica do Serviço de Diagnóstico por Imagem do Hospital das Clínicas da Faculdade de Medicina de Botucatu. Neste estudo foram obtidas imagens radiográficas de mama de excelente qualidade, com redução de dose e carga de tubo, respectivamente, de 36,8% e 46,2%, quando comparadas com a técnica utilizada pela rotina clínica da instituição. CONCLUSÃO: Esta pesquisa vem contribuir com a otimização da relação risco-benefício para o paciente e custo-benefício para a instituição.OBJECTIVE: The aim of this study is the optimization of mammographic images with a considerable radiation dose reduction. MATERIALS AND METHODS: In the present study the X-ray beam was calibrated for each tension (kVp), aiming at determining the best combination between kVp and mAs, resulting in optical densities of about 1.0 above the base-plus-fog density. RESULTS: This study will bring into question the methods for X-ray beam calibration, the choice of the best image by means of visual grading analysis, comparisons between doses and tube load (kVp × mAs) delivered by the techniques described in this study and by those adopted in the clinical routine at Service of Diagnostic Imaging of Faculdade de Medicina de Botucatu Clinics Hospital, Botucatu, SP, Brazil. Excellent breast radiographic images have been obtained with doses and tube loads reduction of respectively 36.8% and 46.2% in comparison to those employed in our institutions' clinical routine. CONCLUSION: This study is a contribution to the optimization of the risk-benefit ratio for patients and cost-benefit ratio for the institution.

Introduction Rhinosinusitis (RS) is an extremely common condition. It causes significant physical symptoms, negatively affects quality of life, and can substantially impair daily functioning. The RS incidence of in the maxillary sinus (MS) is comparatively high. Therefore, computed tomography (CT) of the sinuses is recommended for diagnostic and management purposes. Volume values for MS can be helpful in evaluating the RS, treatment planning and evaluation of the outcome. However, this is not always possible in the clinical routine, and if possible, it involves much effort and/or time. Purpose The aim of this study was to develop an automatic tool to quantity the volume of MS and MS free air in CT exams of patients with rhinosinusitis. Materials and methods The research involved 30 patients. The tool for automatic MS quantification, developed in Matlab, uses a hybrid method, combining watershed and region growing techniques. Our results were compared with radiologist manual segmentation. Results From the comparison, the linear regression showed a strong association and low dispersion. The Bland–Altman analyses showed no significant differences (95% confidence interval). The mean percentage difference between both methods was 9.2% and 10.4% for MS and MS free-air volumes, respectively. Conclusion In conclusion, the developed tool to quantify MS volume proved to be robust, fast and efficient, when compared with manual segmentation. Furthermore, it avoids the intra and inter-observer variations caused by manual and semi-automatic methods. Thus, it may be useful in the diagnosis and treatment determination of RS, providing additional information to physician. Disclosure The authors declare that there is no conflict of interest.