John G. Webster Professor Emeritus Address/E-mail Program Affiliations Courses Education Fields of Interest Publications Summary Files and Links

Contact Information

2148 Engineering Centers Building 1550 Engineering Drive Madison, WI 53706

Tel: 608/263-1574 Fax: 608/265-9239 E-mail: webster@engr.wisc.edu

Program Affiliations

• Biomedical Engineering

• Biomedical Engineering Center for Translational Research

Courses

• BME 200: Biomedical Engineering Design
• BME 310: Introduction to Biomedical Instrumentation
• BME 462: Medical Instrumentation
• BME 515: Therapeutic Medical Devices
• BME 762: Biomedical Instrumentation

Education

• PhD 1967, University of Rochester

Fields of Interest

• medical instrumentation
• radio-frequency and microwave hepatic ablation
• safety of less-lethal electromuscular incapacitation device (EMD): stun guns and Tasers
• biopotential amplifiers and interference
• bioelectrodes

Publications

• View publications on file with the National Library of Medicine.

Summary

My graduate students and I are involved in the following research.

Probe design for liver ablation

We are performing finite element method (FEM) computer models and tests on swine to improve RF ablation, microwave ablation, and cryoablation to cure hepatic cancer. We develop complex finite element method (FEM) models and perform experimental tests to optimize the design of ablation probes capable of producing large lesions. This research includes creation of maps of electrical and thermal properties of the liver, for the range of voltages, current densities and temperatures applicable to RF ablation. We use these data to create realistic and complex FEM models for electrical-thermal FEM analyses. Computer simulations find the optimal probe design. These simulations determine: (a) optimal probe geometry; (b) optimal placement of inner temperature sensors for the purpose of efficient temperature-controlled ablation; (c) optimal power application and ablation procedure duration. These findings clarify the electrical-thermal response of the probe-tissue system during ablation. Experimental tests on anesthetized swine validate temperature and electric field distributions predicted by the computer FEM models.

For more information see: Medical ablation technology group web site below.

Modeling electric current flow through the human body

We will model on a computer the flow of electric current through the human body as the result of the application of an electromuscular incapacitation device, experimentally validate the model on anesthetized swine, who will feel no pain, and determine safety margins related to potential cardiac fibrillation in humans See Electromuscular incapacitating devices below.

Miniature sternal skin-attached hot flash recorder

Hot flashes cause loss of sleep and workplace disruptions in some menopausal women. In testing potential therapies, subjective diaries are unreliable. Present objective recorders of skin conductance changes are bulky. We will develop a miniature recorder to collect objective data. See hot flash below.

Files and Links of Interest

• A miniature monitor automatically detects number of hot flashes for a week on ambulatory subjects: 2007 Annual Meeting North American Menopause Society
• A miniature skin-attached hot flash recorder: IFMBE Proc., 15, 1-4, 2006
• A miniature sternal skin-attached hot flash recorder: IFMBE Proc. 2006 14:577-580.
• Analog signal processing
• Bioinstrumentation
• Calendar: times not available
• Can Tasers directly cause ventricular fibrillation?: IFMBE Proc, 2006, 14: 3307-3310.
• Community of Science profile
• Dart-to-heart distance when Taser causes ventricular fibrillation in pigs: IFMBE Proc., 15, 578-583, 2006.
• Design for Biomedical Engineers: Chapters of a book I am developing
• Electrical measurement, signal processing, and displays
• Electromuscular incapacitating device VF: Will et al. (2006) 2006 Experimental Biology Meeting. Abstract #327
• Electromuscular incapacitating device safety: IFMBE Proc. 2005 11(1)
• Electromuscular incapacitating devices: IFMBE Proc. 2005:9
• Encyclopedia of medical devices and instrumentation, 2nd edition
• Encyclopedia of medical devices and instrumentation, 2nd edition: Table of contents
• Finding employment in medical device companies
• ISI Highly Cited: Search on Webster
• Medical ablation technology group
• Medical instrumentation: application and design, 3rd ed.
• Minimally invasive medical technology
• Resume
• Sensors and signal conditioning, 2nd ed
• Taser Braidwood Inquiry: for Webster view presenter, view transcript
• Taser blunt probe dart-to-heart distance causing ventricular fibrillation in pigs: IEEE Trans. Biomed. Eng., in press
• Taser thesis: Hongyu Sun
• The Measurement, Instrumentation, and Sensors Handbook
• Wiley encyclopedia of electrical and electronics engineering: 24 volumes

Copyright 2008 The Board of Regents of the University of Wisconsin System Date last modified: 05-Sep-2008 Content by: webster@engr.wisc.edu Accessibility Web services UPDATE PROFILE