Introduction Textbook • Bioelectromagnetism : Principles and Application of Bioelectric and Biomagnetic Field – Jaakko Malmivuo/Robert Plonsey Jaakko Malmivuo, PhD Professor, Aalto University – Oxford University Press/1995 Department of Electronics AALTO, FINLAND • Bioelectromagnetism Portal – http://www.bem.fi/ – Textbook & Related information Robert Plonsey, Ph. D. Professor Emeritus, Duke University Biomedical Engineering Bioelectromagnetism • Discipline examining electric, electromagnetic, & magnetic phenomena in biological tissues – Behavior of excitable tissue(the sources) – Electric currents and potentials in the volume conductor – Magnetic field at and beyond the body – Response of excitable cells to electric and magnetic field stimulation – Intrinsic electric and magnetic properties of the tissue • cf: medical electronics: actual devices for this Related Disciplines • Physics & Engineering Biology & Medicine • Biophysics: biological problems with physics. • Bioelectromagnetism: biology + electromagnetic physics. • Biotechnology: microbiological process technology for agriculture, food and drug production. • Biomedical engineering: application of science and technology to biology and medicine. • Bioengineering: biomedical Eng. + biotechnology Related Disciplines • Physics & Engineering Biology & Medicine • Medical physics: science based on physical problems in clinical medicine. • Medical electronics: electronic devices and methods in medicine. • Medical engineering: engineering + medicine • Clinical engineering: applying and implementing medical technology to optimize healthcare delivery BEM & Disciplines Subdivision • Maxwell’s equation: electromagnetic connection – Bioelectric field Biomagnetic field Source Medium External Electric Electric Bioelectricity Electric Magnetic Bioelectromagnetism (Biomagnetism) Magnetic Magnetic Biomagnetism Magnetic Electric - Subdivision • Principle of Reciprocity – Measurement, Stimulation, Impedance Measurement Source Medium External Source Medium External Stimulation Measurement of Source External Medium Intrinsic Property Measurement From neural cells From neural cells From other tissues - EEG, ENG, ERG - MEG, MNG, MRG - Magnetopneumogram From muscle cells From muscle cells - Magnetohepatogram - ECG, EMG - MCG, MMG From other tissues From other tissues - EOG, ENG - MOG, MNG electronystagmography Stimulation • Electric and magnetic stimulation Transthreshold Stimulation Stimulation - CNS, - CNS, - Motor nerve/muscle - Motor nerve/muscle - Cardiac pacing - Cardiac pacing - Defibrillation - Defibrillation Therapy - Magnetotherapy Subthreshold Therapy Therapy - Electrotherapy - Electromagnetotherapy - Surgical diathermy Intrinsic Property • Electric and magnetic property measurement - with subthreshold stimulation Impedance Magnetic Magnetic susceptibility - Cardiography, measurement of - Plethysmogrpahy - Peumography electric impedance Magnetic remanence - Tomography Impedance MRI Electrodermal tomography response Chapter Organization - Measurement of Field - (A) Bioelectricity (B) Bioelectromagnetism (C) Biomagnetism Electric field from bioelectric Magnetic field from Magnetic field from source bioelectric source magnetic material 04 Active behavior of the membrane 12 Theory of biomagnetic Not discussed 05 Physiology of the synapse and brain measurements 06 Bioelectric behavior of the heart 14 Magnetoencephalography 07 Volume source and volume 20 Magnetocardiography conductor 08 Source-field models 09 Bidomain model 11 Theoretical methods 13 Electroencephalography 15 12-lead ECG 16 Vectorcardiography 17 Other ECG systems 18 Distortion in ECG 19 ECG diagnosis 28 Electric signals of the eye Chapter Organization - Stimulation and magnetization- (A) Bioelectricity (B) Bioelectromagnetism (C) Biomagnetism Electric stimulation Electric stimulation Magnetization of with electric field with magnetic field material 03 Subthreshold membrane 22 Magnetic stimulation Not discussed phenomena 21 Functional electric stimulation 23 Cardiac pacing 24 Cardiac defibrillation - Measurement of Intrinsic Properties- (A) Bioelectricity (B) Bioelectromagnetism (C) Biomagnetism Electric measurement of Magnetic measurement of Magnetic measurement electric impedance electric impedance of magnetic susceptibility 25 Impedance plethysmography 26 Magnetic measurement of Not discussed 26 Impedance tomography electric impedance 27 Electrodermal response tomography Why bioelectromagnetism? • Vital function of living organism. – Membrane potential • Life begins with a change in membrane potential – Fertilization of egg with sperm • Change in membrane potential prevent further accesses. • Easily & simply measured – Directly with electrode/magnetometer – Real-time by noninvasive methods Why bioelectromagnetism? • Signal transmission for information & control – Sensory, motor, and for regulation • Basis for electronic implementation – Diagnostic devices, implantable devices – Rapidly developing in medical diagnosis & therapy • Behavior in living tissue – Cellular, organic & subcellular level • Current through single channel: Patch clamp – Application to molecular biology • Development of pharmaceuticals History: Electric fish • 1st document & experiment 메기 – Electric sheatfish(catfish) 상형문자 • Egyptian hieroglyph: 4000BC 무덤벽화 • Sepulcher fresco: 1868 • Electric shock: 450V – 1st medical application • With torpedo fish: AD46 • Headache and gout arthritis • Unique way to get electricity until 17th century History: Amber • Amber: attract light substance – Arostotle(384-22BC), – Thales(625-547BC) – Smith(1931) • Electroscope: Gilbert(1600) – Turn toward the substance of attracting power (Electriks) the Greek name for amber – Published in “De magnete” Muscle contraction • By “animal spirit”, “nervous inflow”? water • Experiments for volume change droplet – Swammerdam(1664) • No movement of water droplet silver • No inflow of nervous fluid ! wire st copper • 1 motor nerve stimulation loop – By emf from bimetallic junction • Current flow within muscle after 1st stimulation: biological origin – Electrical or mechanical stimulation? 1st Electric Machine • Generate static electricity – Otto von Guericke(1672) : By rotation – Sphere of sulfur + Iron axle in wooden framework • Rotating glass wheel: Francis Hauksbee(1709) – Evacuating glass Brilliant light Cathode ray, x-ray, electron • Electricity has usefulness only for medicine – Johan G. Kruger(1743) Electromagnetic Stimulation • 4 different historical period – Static electricity: Benjamin Franklin(1706-1790) – Direct current: Luigi Galvani (1737-1798) – Induction coil shocks: Michael Faraday(1791-1867) – RF current: Jacques d'Arsonval (1851-1940) Metal foil on inner & outer • Leyden jar: capacitor surfaces – Kleist: 1745 – Musschenbroek: 1746 • Leyden U. Netherlands – Ramsden: 1768, 1st practical generator Benjamin Franklin • Founding Fathers of the United States, 박식가 • “The 1st American“ & Polymath: – Author, printer, political theorist, politician, scientist, postmaster, inventor, civic activist, statesman, diplomat. • Concept of +/- electricity • Atmospheric electricity – Kite experiment: 1752 • Lightning: electricity • Collecting into Leyden jar • Invention of lightning rod Portraits in US Dollars George Andrew Washington Jackson 1st President 7th President Ulysses S. Thomas Grant Jefferson 18th President 3rd President Abraham Benjamin Lincoln Franklin st 16th 1 US President Ambassador to France 1st American Alexander Hamilton 1st US Secretary of the Treasury Muscle Stimulation • Jean Jallabert: 1747 – Prof. in mathematics in Genova – Electrical stimulation to hand paralyzed patient • For 3 months & successful • Beginning of therapeutic stimulation of muscle by electricity • Lugi Galvani: Jan. 26. 1781 – Prof. in anatomy, U. of Bologna • Electrical stimulation of femoral nerve of frog • Violent muscular contraction – 1st neuromuscular electric stimulation Lugi Galvani • Study with atmospheric electricity zinc – Frog leg contraction on lightning • Study on calm weather – Iron railing in garden cooper – Brass hook inserted in spinal cord – Contraction on contacting • Stimulation by bimetallic arch – Did not understand mechanism of bimetallic voltage • Just discharging the animal bioelectricity Alessandro Volta • Physicist, Univ. of Pavia • Current not from animal – “Metallic current” • metals muscle – Electricity can be a powerful stimulus for nerves and muscles • Volta bimetallic pile – 1st battery: 1800 – “Artificial electrical organ” • In contrast to torpedo fish – Q=CV, capacitor Animal or Metal Current • Galvani vs. Volta • Giovanni Aldini – Assistant & Nephew of Galvani – Physicist, Univ. of Bologna – Strong supporter of Galvani • Series of experiment without using two metals: 1804 – Stimulation with voltatic piles – Water filled vessel as electrodes Giovanni Aldini • Muscle contraction on cadavers – By electrical stimulation – Facial contraction by brain stimulation – Not successful with heart muscle Giovanni Aldini • Mental disorder treatment: Depression – 1st brain stimulation • Reanimation(?) on drowned person – Inspired electrical stimulation in heart failure – Cardiac pacemaker & defibrillator Cardiorespiratory Resuscitation • T. Green: 1872 • Resuscitate surgical patient – Anesthetized with chloroform • depressing respiration and cardiac pulse – With battery of 300volts • Btw neck and lower rib on the left – Successful on 5~7 patients • On subject with sudden respiratory arrest, without pulse Induction Coil • High voltage of alternating current in 2nd