Application of NEMA protocols to verify GATE models based on the Digital Biograph Vision and the Biograph Vision Quadra scanners.

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 (∼38%) 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.

Humoral and cellular immune responses to Pfizer-BioNTech BNT162b2 SARS-CoV-2 vaccine in adolescents with liver transplantation: Single center experience.

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.

An Intensive Lifestyle Intervention Is an Effective Treatment of Morbid Obesity: The TRAMOMTANA Study-A Two-Year Randomized Controlled Clinical Trial.

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.

One year weight loss in the TRAMOMTANA study. A randomized controlled trial.

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.

Puntos clave en la puesta en marcha y desarrollo de un Ensayo Clínico. De la pregunta a la realidad de un Ensayo Clínico investigador iniciado (I) / Key points in the start and conduct of a clinical trial. From question to reality in an investigator-initiated clinical trial (I)

La práctica clínica basada en la evidencia requiere la integración de la experiencia profesional individual con los mejores datos objetivos para tomar la mejor decisión terapéutica. Los datos científicos de mejor grado de evidencia derivan de ensayos clínicos controlados y aleatorizados e investigaciones de vigilancia farmacológica poscomercialización y metaanálisis. En muchas ocasiones durante nuestras actividades clínicas buscamos sin éxito el ensayo clínico que conteste a nuestras preguntas científicas. Es en estos momentos cuando en ocasiones nos planteamos la puesta en marcha de un ensayo clínico. Si usted como investigador clínico tiene una pregunta científica (relevante), que potencialmente requeriría la realización de un Ensayo Clínico para alcanzar una respuesta y carece del respaldo de una Compañía Farmacéutica para llevarlo a cabo, quizá encuentre de utilidad la lectura de este artículo, en el que intentamos presentar de forma breve y clarificadora la normativa regulatoria para planificar un Ensayo Clínico, con la humilde intención de que se convierta en una herramienta útil para cualquier investigador independiente (AU)

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 researche (AU)

TRAMOMTANA (Tratamiento Multidisciplinar de la Obesidad Mórbida: Medicamentos, Terapia de comportamiento, Apoyo Nutricional y Actividad física). De la pregunta a la realidad de un ensayo clínico investigador iniciado (II) / TRAMOMTANA (Multidisciplinary treatment of morbid obesity: Medication, behavioral therapy, nutritional support, and physical activity). From question to reality in an investigator-initiated clinical trial (II)

Comunicamos la puesta en marcha de un programa intensivo y multidisciplinar de pérdida de peso en pacientes con obesidad mórbida (OM). Este ensayo clínico se basa en la educación para la salud, el apoyo en el proceso de cambio, los medicamentos y las sesiones de terapia de grupo. Nuestra intención es demostrar que los resultados obtenidos con este programa de pérdida de peso a 2 años son, cuando menos, comparables a los resultados que se obtienen con la cirugía bariátrica en estos pacientes con OM. Es nuestra intención igualmente (..) (AU)

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 (AU)

[TRAMOMTANA (Multidisciplinary treatment of morbid obesity: medication, behavioral therapy, nutritional support, and physical activity). From question to reality in an investigator-initiated clinical trial (II)]. / TRAMOMTANA (Tratamiento Multidisciplinar de la Obesidad Mórbida: Medicamentos, Terapia de comportamiento, Apoyo Nutricional y Actividad física). De la pregunta a la realidad de un ensayo clínico investigador iniciado (II).

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.

[Key points in the start and conduct of a clinical trial. From question to reality in an investigator-initiated clinical trial (I)]. / Puntos clave en la puesta en marcha y desarrollo de un Ensayo Clínico. De la pregunta a la realidad de un Ensayo Clínico investigador iniciado (I).

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.

Diagnóstico en hospitalización y análisis de la efectividad del Servicio de Cirugía del Hospital "Dr. Luis Salazar Domínguez" / Hospitalization diagnosis and analysis of the effectiveness of Service of Surgery the Hospital \"Dr. Luis Salazar Dominguez\"

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

Pólipo duodenal solitario: presentación de un caso y revisión de la literatura / Isolated duodenal polyp: a case report and review of the literature

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

Seudoquiste esplénico: presentación de un caso y revisión de la literatura / Splenic pseudocysts: report of a case an review of the literature

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