How Accurate are Therapeutic Ultrasound Machines?

Low-Cost Thermochromic Quality Assurance Phantom for Therapeutic Ultrasound Devices: A Proof of Concept

High-intensity focused ultrasound (HIFU) transducer acoustic output can vary over time as a result of an inconsistent power supply, damage to the transducer or deterioration over time. Therefore, easy implementation of a daily quality assurance (DQA) method is of great importance for pre-clinical research and clinical applications. We present here a thermochromic material-based phantom validated by thermal simulations and found to provide repeatable visual power output assessments in fewer than 15 s that are accurate to within 10%. Whereas current available methods such as radiation force balance measurements provide an estimate of the total acoustic power, we explain here that the thermochromic phantom is sensitive to the shape of the acoustic field at focus by changing the aperture of a multi-element transducer with a fixed acoustic power. The proposed phantom allows the end user to visually assess the transducer's functionality without resorting to expensive, time-consuming hydrophone measurements or image analysis.

Efeitos adversos da eletrotermofototerapia em clínicas da cidade de Cascavel - PR

RESUMO Esta pesquisa teve como objetivo identificar os principais efeitos adversos observados por fisioterapeutas com o uso de aparelhos de eletrotermofototerapia em clínicas da cidade de Cascavel, Paraná. A amostra contou com 35 clínicas e destas, 25 foram alvo de coleta após triagem, cujos dados foram obtidos por questionários em forma de entrevista semiestruturada. Nestes se questionava aos responsáveis pelo serviço de eletrotermofototerapia sobre a ocorrência de efeitos adversos experienciados durante atividades laborais na clínica. Observou-se que a Neuroestimulação Elétrica Transcutânea (TENS) apresentou problemas em 64% dos casos, com 36% devido a irritações cutâneas e 28% a dor. O aparelho de ondas curtas apresentou efeitos adversos em 60%, em que 40% foram queixas de dor e 20% causaram queimaduras leves. Já acerca do ultrassom terapêutico foram relatados efeitos adversos em 52%, sendo 32% de quadros de dor e 20% de casos com náuseas. A laserterapia de baixa potência demonstrou efeito adverso em 36%, com relatos de aumento da sensibilidade local. Por fim, os aparelhos de média frequência apresentaram efeitos adversos em apenas 20% dos casos, de queixas de náuseas. A quantidade de tais efeitos encontrados foi importante, porém sua gravidade não causou grande preocupação.

Thermochromic Phantom and Measurement Protocol for Qualitative Analysis of Ultrasound Physiotherapy Systems

Thermochromic test bodies are promising tools for qualitatively evaluating the acoustic output of ultrasound physiotherapy systems. Here, a novel phantom, made of silicone mixed with thermochromic powder material, was developed. Additionally, a procedure was developed to evaluate the stability and homogeneity of the phantom in a metrologic and statistical base. Twelve phantoms were divided into three groups. Each group was insonated by a different transducer. An effective intensity of 1.0 W/cm(2) was applied to each phantom; two operators performed the procedure three times in all phantoms. The heated area was measured after image processing. No statistical difference was observed in the heated areas for different samples or in the results for different operators. The heated areas obtained using each transducer were statistically different, indicating that the thermochromic phantom samples had sufficient sensitivity to represent the heated areas of different ultrasonic transducers. Combined with the evaluation procedure, the phantom provides an approach not previously described in the literature. The proposed approach can be used to quickly assess changes in ultrasonic beam cross-sectional shape during the lifetime of ultrasound physiotherapy systems.