RESUMEN
Manual segmentation of target structures and organs at risk is a crucial step in the radiotherapy workflow. It has the disadvantages that it can require several hours of clinician time per patient and is prone to inter- and intra-observer variability. Automatic segmentation (auto-segmentation), using computer algorithms, seeks to address these issues. Advances in machine learning and computer vision have led to the development of methods for accurate and efficient auto-segmentation. This review surveys auto-segmentation techniques and applications in radiotherapy planning. It provides an overview of traditional approaches to auto-segmentation, including intensity analysis, shape modelling and atlas-based methods. The focus, though, is on uses of machine learning and deep learning, including convolutional neural networks. Finally, the future of machine-learning-driven auto-segmentation in clinical settings is considered, and the barriers that must be overcome for it to be widely accepted into routine practice are highlighted.
Asunto(s)
Aprendizaje Profundo , Órganos en Riesgo , Humanos , Procesamiento de Imagen Asistido por Computador , Aprendizaje Automático , Variaciones Dependientes del Observador , Planificación de la Radioterapia Asistida por ComputadorRESUMEN
We report three cases of intrasubstance failure of a LARS™ (Ligament Augmentation and Reconstruction System) artificial ligament used for acromioclavicular joint reconstruction. The LARS™ ligament failed within four months of the index procedure. All patients underwent a revision procedure following an unsuccessful trial of conservative management. A modified second loop technique was employed during the revision procedure for all cases using the LARS™ ligament. All three patients achieved full recovery to pre-injury level function.
Asunto(s)
Artroplastia/instrumentación , Luxaciones Articulares/cirugía , Ligamentos Articulares/cirugía , Prótesis e Implantes/efectos adversos , Falla de Prótesis/efectos adversos , Articulación Acromioclavicular/cirugía , Adulto , Anciano , Artroplastia/efectos adversos , Artroplastia/métodos , Materiales Biocompatibles/efectos adversos , Humanos , Ligamentos Articulares/lesiones , Masculino , Recurrencia , Reoperación , Resultado del TratamientoRESUMEN
Plasma HIV RNA is a useful surrogate marker for predicting HIV-1 disease progression in infected individuals but provides no information regarding the infectious viral titer. Traditional assays of infectious HIV-1 are, however, time consuming, insensitive, use non-standardized reagents and are subject to selection bias introduced by prolonged cultivation. In this pilot study infectious HIV-1 was detected directly in patient plasma using the indicator line HeLa-CD4-CCR5-LTR/beta-gal in a centrifugation-culture method. Replication competent HIV-1 was identified within 2 days of tissue culture inoculation in six (26%) of 23 plasma specimens. The capability of a new cell line, MT4-CCR5-tat, to amplify plasma HIV-1 was also tested. HIV was cultivated from ten (71%) of 14 specimens using MT4-CCR5-tat cells before titering the virus with the indicator cell assay. Using these stable cell lines in refined versions of this assay it may be feasible to develop rapid, simple methods for titering infectious plasma HIV-1 and for testing the susceptibility of the virus to antiretroviral drugs.
Asunto(s)
Sangre/virología , Infecciones por VIH/virología , VIH-1/aislamiento & purificación , VIH-1/fisiología , Antígenos CD4/metabolismo , Línea Celular , Centrifugación , Duplicado del Terminal Largo de VIH/genética , VIH-1/genética , Células HeLa , Humanos , Proyectos Piloto , ARN Viral/sangre , Receptores CCR5/metabolismo , Viremia/virología , Cultivo de Virus , beta-Galactosidasa/genética , beta-Galactosidasa/metabolismoRESUMEN
Sera from 1000 women attending antenatal clinics were screened for the presence of rubella antibody by haemagglutination inhibition (HI), single radial haemolysis (SRH), and enzyme-linked immunosorbent assay (ELISA). With 925 sera concordant results were obtained with all three tests. There were 46 false-negative HI tests due to the necessity of allowing for residual non-specific inhibitors. With SRH there was one false positive and three that were negative by SRH but HI- and ELISA-positive. By ELISA 14 sera gave a false-positive result (OD 405 nm greater than or equal to 0.2). Ten of these could be eliminated by taking an OD 405 nm of 0.5 as the threshold but then another 10 sera became false negatives.
Asunto(s)
Anticuerpos Antivirales/análisis , Tamizaje Masivo/métodos , Virus de la Rubéola/inmunología , Rubéola (Sarampión Alemán)/prevención & control , Ensayo de Inmunoadsorción Enzimática , Reacciones Falso Negativas , Reacciones Falso Positivas , Femenino , Pruebas de Inhibición de Hemaglutinación , Técnica de Placa Hemolítica , Humanos , EmbarazoRESUMEN
The spread of adenovirus type 7 in England and Wales between 1971 and 1974 and the clinical features of infections with this virus were investigated in a retrospective study of virological reports and patients' clinical records. An epidemic in 1972-74 apparently stared in the North-East and spread to the South-West. Between March 1973 and the end of October 1974 the virus was recovered in 59 of 74 specimens from 42 patients. The mean age of the patients was 9 years, which suggests that a large pool of young susceptibles was important in the dissemination of the epidemic. Sore throats, cervical lymphadenopathy, conjunctivitis, and abdominal pain were common symptoms. Meningism was present in 12 patients; 2 cases had apparent neuropsychiatric sequelae.
