Utilização de magnetorresistores no desenvolvimento de novas técnicas para aplicações em gastroenterologia

• Autor(a) principal: Paixão, Fabiano Carlos [UNESP]
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/110776
• topic: Fisica medica; Gastroenterologia - Diagnóstico - Técnicas; Biomagnetismo; Enteral feeding tube

Biomagnetic techniques have been employed successfully to study gastrointestinal (GI) tract. They are enable to measure the magnetic field of magnetized markers, the markers and tracers responses to applied magnetic field excitation, and the magnetic field occurred by GI electrical activity. This work presents some instrumentation developed to evaluate different parameters of GI tract. The equipment built uses anisotropic magnetoresistive (AMR) sensor to measure magnetic field and true rms-to-dc voltage converter in order to reduce the cost of techniques that employ alternate (AC) magnetic excitation. In this work were developed: a magnetic method for localization of enteral feeding tube, a solution to replace lock-in amplifier for true rms converter, an instrumentation using AMR sensor (one axis-sensing) to evaluate the pharyngeal transit time, another instrumentation using AMR sensor (three axis-sensing) to evaluate esophageal transit time and finally, a equipment consisted of 36 AMR sensors to evaluate the gastric motor activity from rats and in order to obtain magnetic images from different kinds of phantoms. All equipments were tested and showed sensitivity to be employed in GI studies. The equipments developed are low cost, radiation free, portable and enable to applications in gastroenterology, pharmacology, pharmaceutical and medical clinic.