RESUMO
In large multi-center studies it is important to quantify data variations due to differences between sites and over time. Here we investigate inter-site variability in signal to noise ratio (SNR), percent integral uniformity (PIU), width and height using the American College of Radiology (ACR) phantom scans from the NIHPD project. Longitudinal variations are also analyzed. All measurements are fully automated. Our results show that the mean SNR, PIU and the 2 metric values were statistically different across sites. The maximum mean difference in diameter across sites was 2 mm (1.1%), and the maximum mean difference in height was 2.5 mm (1.7%). Over time, an average drift of 0.4 mm per year was observed for the diameter while a drift of 0.5 mm per year was observed for the height. Trends observed over time often depended not only on site, but also on modality and scanner manufacturer.
Assuntos
Encéfalo/anatomia & histologia , Interpretação de Imagem Assistida por Computador/métodos , Interpretação de Imagem Assistida por Computador/normas , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/instrumentação , Imageamento por Ressonância Magnética/normas , Imagens de Fantasmas/normas , Inteligência Artificial , Criança , Análise de Falha de Equipamento , Humanos , National Institutes of Health (U.S.) , Reconhecimento Automatizado de Padrão/métodos , Reconhecimento Automatizado de Padrão/normas , Garantia da Qualidade dos Cuidados de Saúde/métodos , Garantia da Qualidade dos Cuidados de Saúde/normas , Valores de Referência , Estados UnidosRESUMO
In contemporary brachytherapy procedures, needle placement at the desired target is challenging due to a variety of reasons. A robot-assisted brachytherapy system can improve the needle placement and seed delivery resulting in enhanced patient care. In this paper we present a 16 DOF (degrees-of-freedom) robotic system (9DOF positioning module and 7 DOF surgery module) developed and fabricated for prostate brachytherapy. Techniques to reduce needle deflection and target movement have been incorporated after verifying with extensive experiments. Provisions for needle motion and force feedback have been included into the system for improving the robot control and seed delivery. Preliminary experimental results reveal that the prototype system is quite accurate (sub-millimeter) in placing brachytherapy needles.