RESUMO
Purpose: Test objects for High Intensity Focused Ultrasound (HIFU) are required for the standardization and definition of treatment, Quality Assurance (QA), comparison of results between centers and calibration of devices. This study describes a HIFU test object which provides temperature measurement as a function of time, in a reference material compatible with Magnetic Resonance (MR) and ultrasound.Materials and methods: T-Type fine wire thermocouples were used as sensors and 5 correction methods for viscous heating artifacts were assessed. The phantom was tested in a MR-HIFU Philips Sonalleve device over a period of 12 months, demonstrating stability and validity to evaluate the performance of the device.Results: The study furnished useful information regarding the MR-HIFU sessions and highlighted potential limitations of the existing QA and monitoring methods. The importance of temperature monitoring along the whole acoustic path was demonstrated as MR Thermometry readings differed in the three MR plane views (coronal, sagittal, transverse), in particular when the focus was near a soft-tissue/bone interface, where there can be an MR signal loss with significant temperature and thermal dose underestimation (138% variation between the three plane views).Conclusions: The test object was easy to use and has potential as a valid tool for training, QA, research and development for MR guided HIFU and potentially ultrasound guided devices.
Assuntos
Ablação por Ultrassom Focalizado de Alta Intensidade , Termometria , Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Imageamento por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética , Imagens de Fantasmas , Termometria/métodosAssuntos
Infecções por Coronavirus/prevenção & controle , Transmissão de Doença Infecciosa do Paciente para o Profissional/prevenção & controle , Transmissão de Doença Infecciosa do Profissional para o Paciente/prevenção & controle , Pandemias/prevenção & controle , Equipamento de Proteção Individual , Pneumonia Viral/prevenção & controle , Ultrassonografia Pré-Natal/métodos , COVID-19 , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/transmissão , Contaminação de Equipamentos/prevenção & controle , Dispositivos de Proteção dos Olhos , Feminino , Luvas Protetoras , Ginecologia , Higiene das Mãos , Pessoal de Saúde , Humanos , Máscaras , Programas de Rastreamento , Obstetrícia , Pneumonia Viral/diagnóstico , Pneumonia Viral/transmissão , Gravidez , Dispositivos de Proteção Respiratória , Triagem , Ultrassonografia/métodos , VentilaçãoAssuntos
Betacoronavirus , Infecções por Coronavirus , Técnicas de Diagnóstico Obstétrico e Ginecológico , Segurança de Equipamentos/normas , Higiene , Pandemias , Pneumonia Viral , COVID-19 , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/transmissão , Técnicas de Diagnóstico Obstétrico e Ginecológico/normas , Feminino , Doenças dos Genitais Femininos/diagnóstico , Humanos , Higiene/normas , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Pneumonia Viral/transmissão , Gravidez , SARS-CoV-2 , Sociedades MédicasRESUMO
PURPOSE: In this work we provide measurements of speed of sound (SoS) and acoustic impedance (Z) of some doped/non-doped rubber-based materials dedicated to the development of ultrasound phantoms. These data are expected to be useful for speeding-up the preparation of multi-organ phantoms which show similar echogenicity to real tissues. METHODS: Different silicones (Ecoflex, Dragon-Skin Medium) and polyurethane rubbers with different liquid (glycerol, commercial detergent, N-propanol) and solid (aluminum oxide, graphene, steel, silicon powder) inclusions were prepared. SoS of materials under investigation was measured in an experimental setup and Z was obtained by multiplying the density and the SoS of each material. Finally, an anatomically realistic liver phantom has been fabricated selecting some of the tested materials. RESULTS: SoS and Z evaluation for different rubber materials and formulations are reported. The presence of liquid additives appears to increase the SoS, while solid inclusions generally reduce the SoS. The ultrasound images of realized custom fabricated heterogeneous liver phantom and a real liver show remarkable similarities. CONCLUSIONS: The development of new materials' formulations and the knowledge of acoustic properties, such as speed of sound and acoustic impedance, could improve and speed-up the development of phantoms for simulations of ultrasound medical procedures.