Prof. John G. Webster, USA
Back to the list of Invited Speakers
 | Prof. John G. Webster, USA
Professor Emeritus of Biomedical Engineering |
| Short CV | John G. Webster received the B.E.E. degree from Cornell University, Ithaca, NY, USA in 1953, and the M.S.E.E. and Ph.D. degrees from the University of Rochester, Rochester, NY, USA in 1965 and 1967, respectively. He is Professor Emeritus of Biomedical Engineering at the University of Wisconsin-Madison, USA. In the field of medical instrumentation he teaches undergraduate and graduate courses in bioinstrumentation and design. He does research on improving electrodes for ablating liver to cure cancer. He does research on safety of electromuscular incapacitating devices. He is the editor of the most-used text in biomedical engineering: Medical instrumentation: application and design, Third Edition New York, John Wiley & Sons, 1998, and has developed 22 other books including the Encyclopedia of medical devices and instrumentation, New York: John Wiley & Sons, 1988 and 180 research papers. Dr. Webster is a fellow of the Institute of Electrical and Electronics Engineers, Instrument Society of America, American Institute of Medical and Biological Engineering, and Institute of Physics. He has been a member of the IEEE-EMBS Administrative Committee and the NIH Surgery and Bioengineering Study Section. He is the recipient of the 2001 IEEE-EMBS Career Achievement Award. |
| Title: | Tissue ablation: devices and procedures |
| Abstract | Ablation is a method of delivering physical, chemical, or energy treatment to tissue for the purpose of removing, altering, creating scar tissue or causing aposis (cell death). Cardiac accessory pathways permit ventricular excitation to escape to the atria and cause ventricular tachycardia. Catheters permit mapping the location of the accessory pathways. 2.6 mm diameter catheter electrodes pass 450 kHz power of about 20 W for about 20 s to heat the pathway above 50 C to kill the pathway tissue. To kill hepatic cancer, the radiologist inserts a probe percutaneously, expands an umbrella-like array and applies power for about 8 min. Alternatively in an open procedure the surgeon can heat using a variety of probes or freeze using cryo-ablation. To avoid exceeding 100 C, which causes charring, steam and popping, saline may circulate through the probe interior or perfuse into the tissue. Microwave ablation provides quicker heating to prevent hepatic vessels from carrying heat away during ablation. Finite element method electrical-thermal models help to develop new methods including bipolar, multiple, phased array, noncontact and needle electrodes. Applications include ablation of prostate, brain, gastrointestinal tract, capsule, breast, varicose veins, blood clots, skin wrinkles, cornea, teeth, and bone. |
