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PURPOSE: The Monte Carlo method is an effective tool to simulate and verify PET systems. Furthermore, it can help in the design and optimization of new medical imaging devices and algorithms. In this framework, the goal of this work is to verify the GATE toolkit performance when applied to simulate two Siemens Healthineers PET scanners: a standard axial field-of-view Biograph Vision scanner and the new long axial field-of-view Biograph Vision Quadra scanner. METHODS: The simulation toolkit GATE is based on GEANT4, comprising its main functionalities and a set of domain-specific features in the field of medical physics. To accomplish our purpose, the guidelines described in the NEMA NU 2-2018 protocol are reproduced. Then the simulated results are compared to experimental data available in the literature for both PET scanners. The assessment of the models includes different studies of sensitivity, count rate performances, spatial resolution and image quality. These tests are intended to evaluate the image quality of PET devices. RESULTS: In the spatial resolution test, relative errors lower than 8% are obtained between the experiments and GATE models. The sensitivity is 17.2 cps/kBq (Vision) and 175.9 cps/kBq (Quadra), representing relative differences with the experiment of 6% and 0.3%, respectively. Deviations from peak NECR are less than 9%. In the Image Quality test, the contrast recovery coefficient for hot spheres, with 8 iterations and 5 subsets, ranges between 57-83% for Vision and 54-86% for Quadra. These values represent a maximum deviation between the simulations and the experiments of 10% for the Quadra scanner. In the case of the Vision scanner, the highest difference is observed for the 10 mm sphere (â¼38%) due to the higher contrast recovery of the experiment caused by the Gibbs artifact from the use of PSF reconstruction. CONCLUSIONS: The results of the simulations have provided evidence of a good agreement between the experimental data and the results obtained with GATE. Thus, this work supports the capability of this MC toolkit to accurately simulate the models of the Vision and Quadra scanners. This study has laid the basis for further research in this field and has identified several areas that could be explored.
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Background: Immune responses to vaccines against severe acute respiratory syndrome (SARS)-coronavirus (CoV)-2 are variable. In the absence of disease, youngsters are expected to better react to vaccines than adults. Nevertheless, chronic immunosuppression in transplant recipients may impair their capability to generate protection. We aim to explore immune responses after BNT162b2 SARS-CoV-2 vaccination in our cohort of young liver-transplanted patients. Methods: A prospective study of adolescent liver-transplanted patients (n=33) in the long-term follow-up was performed. Immune responses after receiving Pfizer-BioNTech BNT162b2 vaccine were analyzed at two time-points: baseline and 30 days after the second dose. Humoral responses were measured by fluoroenzyme-immunoassay and T-cell responses by interferon-γ-release assay. Post-vaccine coronavirus disease (COVID-19) events were recorded by a survey. Results: Pre-vaccine SARS-CoV-2-specific antibodies were undetectable in 27/32 (84.4%), negative/indeterminate in 3/32 (9.4%) and positive in 2/32 (6.3%) patients. Cellular responses at baseline were negative in 12/18 (66.6%), positive in 3/18 (16.6%) and indeterminate in 3/18 (16.6%) recipients. None of the baseline positives recalled any symptoms. Post-vaccine antibodies were detected in all patients and 92.6% showed levels >816 BAU/mL. Twenty (71.4%) recipients had positive T-cell responses. Regarding post-vaccine SARS-Cov-2 infection, 10 (30.3%) patients reported COVID-19 without hospitalization and 21 (63.6%) did not notify any infection. Negative and positive cell-response groups after vaccination showed statistically significant differences regarding COVID-19 cases (62.5% vs 22.2%, respectively; p=0.046). Conclusions: Adolescents and young adults with liver transplantation responded to SARS-Cov-2 vaccine, generating both humoral and cellular responses. Recipients developing cellular responses after vaccination had a lower incidence of COVID-19.
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COVID-19 , Transplante de Fígado , Vacinas , Adolescente , Adulto Jovem , Humanos , SARS-CoV-2 , Vacinas contra COVID-19 , Vacina BNT162 , Transplante de Fígado/efeitos adversos , Estudos Prospectivos , COVID-19/prevenção & controle , Anticorpos Antivirais , Imunidade CelularRESUMO
Bariatric surgery is currently the most effective therapy to induce weight loss in morbidly obese patients. Objective. This controlled, clinical trial with a two-year intervention was aimed at comparing the efficacy of two nonsurgical approaches versus bariatric surgery, on body weight changes and metabolic parameters in morbidly obese patients. Methods. Patients were randomized to an Intensive Lifestyle Intervention (ILI) (n = 60) or Conventional Obesity Therapy (COT) (n = 46). The ILI group received behavioral therapy and nutritional counseling. The COT group received standard medical treatment. They were compared with a third group, Surgical Obesity Group (SOG) (n = 37). Results. Patients who received ILI had a greater percentage of weight loss than patients receiving COT (-11.3% versus -1.6%; p < 0.0044). Interestingly 31.4% of patients included in the ILI group were no longer morbidly obese after just six months of intervention, increasing to 44.4% after 24 months of intervention. The percentage weight loss in SOG was -29.6% after that same period of time. Conclusions. ILI was associated with significant weight loss when compared to COT, in a group of patients with obesity. An ILI approach could be an alternative therapy to patients with obesity, who are not candidates to undergo bariatric surgery. This trial is registered with EudraCT 2009-013737-24.
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BACKGROUND: Morbid obesity is a major health problem and bariatric surgery is currently the most effective therapy available to induce weight loss in these patients. This report describes 1-year changes in weight and metabolic parameters, in a trial designed to examine the effects of a nonsurgical approach, Intensive Life style Intervention (ILI) on the therapy of morbid obesity. METHODS: The primary outcome was change in body weight. Patients were randomized to ILI (n = 60) or conventional obesity therapy (COT) (n = 46). The ILI group received behavioural therapy and nutritional/physical activity counselling. The COT group received the standard medical treatment available for these patients. A third group consisted of the patients already included in our bariatric surgery waiting list (n = 37). FINDINGS: We present here 1-year data showing that patients who received ILI with no restrictions in calorie intake had a greater percentage of weight loss than patients receiving COT (-11·58% vs -0·4%; P < 0·001). Importantly, 31·4% of patients included in the ILI group were not morbidly obese after 6 months of intervention. This number increased to 42·8% after 12 months of intervention. INTERPRETATION: ILI was associated with significant weight loss compared with COT in a group of morbidly obese patients. The weight loss effect was already obtained after 6 months of ILI intervention. These results seriously question the efficacy of the COT approach to morbid obesity. Furthermore, they underscore the use of ILI programmes in the hospital setting to effectively treat morbidly obese patients and might help to reduce the number of candidate patients for bariatric surgery.
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Estilo de Vida , Obesidade Mórbida/terapia , Redução de Peso , Adulto , Cirurgia Bariátrica , Terapia Comportamental , Glicemia/metabolismo , Pressão Sanguínea , Aconselhamento , Feminino , Hemoglobinas Glicadas/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Atividade Motora , Avaliação Nutricional , Obesidade Mórbida/patologia , Obesidade Mórbida/cirurgia , Resultado do TratamentoRESUMO
Implementation of an intensive, multidisciplinary weight loss program in patients with morbid obesity is reported. This program is based on behavioral changes, lifestyle intervention, medication, and group therapy sessions. Our objective is to show that the results achieved with this two-year weight loss program will be at least similar to those achieved with bariatric surgery in patients with morbid obesity. We also intend to show that this multidisciplinary treatment induces an improvement in the comorbidity rate associated to smaller costs for our national health system.
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Obesidade Mórbida/terapia , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Adolescente , Adulto , Idoso , Cirurgia Bariátrica/economia , Terapia Comportamental/economia , Terapia Combinada/economia , Comorbidade , Dieta Redutora/economia , Terapia por Exercício/economia , Feminino , Custos de Cuidados de Saúde , Humanos , Masculino , Medicina , Pessoa de Meia-Idade , Apoio Nutricional/economia , Obesidade Mórbida/sangue , Obesidade Mórbida/economia , Obesidade Mórbida/epidemiologia , Obesidade Mórbida/cirurgia , Equipe de Assistência ao Paciente , Seleção de Pacientes , Projetos de Pesquisa , Espanha/epidemiologia , Resultado do Tratamento , Adulto JovemRESUMO
Evidence-based clinical practice requires integration of individual professional experience with the best objective data to make the best therapeutic decision. The best degree of scientific evidence derives from controlled, randomized clinical trials and post-marketing drug surveillance studies and meta-analyses. During our clinical activities, we often search unsuccessfully for a clinical trial which answers our scientific questions. It is at those times that we may sometimes consider the conduct of a clinical trial. If you, as a clinical investigator, have a (relevant) scientific question that could potentially require the conduct of a clinical trial to achieve a response and have no support from a pharmaceutical company to perform it, you may find it useful to read this article, in which an attempt has been made to briefly and clearly explain the applicable regulations for planning a clinical trial. Our humble intention is that this publication becomes a useful tool for any independent researcher.
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Ensaios Clínicos como Assunto/métodos , Ensaios Clínicos como Assunto/economia , Ensaios Clínicos como Assunto/ética , Ensaios Clínicos como Assunto/legislação & jurisprudência , Coleta de Dados , Documentação , Órgãos Governamentais , Humanos , Avaliação de Resultados em Cuidados de Saúde , Projetos de Pesquisa , Pesquisadores , Relatório de Pesquisa , Apoio à Pesquisa como Assunto , Sociedades Médicas , EspanhaRESUMO
Para la realización del presente trabajo fueron obtenidos los datos de los archivos de historias médicas del Hospital "Dr. Luis Salazar" I.V.S.S. (Guarenas; Edo. Miranda). En el lapso comprendido desde abril de 1988 hasta diciembre 1990. Nuestro objetino fue determinar la frecuencia de el diagnóstico en hospitalización y evaluar la eficacia del servicio de cirugía; el cual inició sus actividades desde de 1988 y compararlo con las estadísticas de los distintos hospitales a nivel nacional. Obtuvimos un total de 558 pacientes tanto en emergencia como en forma electiva. Analizamos la incidencia de las patologías más frecuentes, en el grupo etario y su distribución por sexo
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Centro Cirúrgico Hospitalar/organização & administraçãoRESUMO
Se presenta el caso de un paciente con un pólipo pediculado único ubicado en la tercera porción del duodeno cuyo diagnóstico histopatológico correspondió a una lesión inflamatoria y fibrosa, es decir, benigna. Se describieron detalladamente la etiología, patología, clínica, diagnóstico y tratamiento de los pólipos y otros tumores benignos del intestino delgado
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Pessoa de Meia-Idade , Humanos , Masculino , Pólipos Intestinais/cirurgia , Duodeno/patologia , Duodeno/cirurgiaRESUMO
Se presenta el caso de una paciente con un pseudoquiste esplénico sintomático, que con toda seguridad se originó como consecuencia de un traumatismo torácico antiguo (20 años antes), el cual fue diagnosticado con el empleo del ultrasonido y la tomografía axial computarizada y tratado exitosamente con la esplenectomía. Se describen detalladamente la historia, incidencia, etiopatogenia, clínica, diagnóstico y tratamiento de los quistes esplénicos. Se revisaron los índices bibliográficos nacional y latinoamericanos hasta diciembre de 1986 y no se encontró ningún reporte sobre los seudoquistes del bazo