Download EE-416 Biomedical Signals, Instrumentation and Measurement

EE-416 Biomedical Signals,
Instrumentation and Measurement
Introduction
Lecturer: Murat EYÜBOĞLU
Middle East Technical University
Department of Electrical and Electronics Engineering
2017
EE 416 - Biomedical Signals, Instrumentation and Measurement
Instructor: Murat EYÜBOĞLU ([email protected]) (Office: DZ-09)
• Course Description: Fundamentals of biomedical signals,
measurement and instrumentation; biomedical transducers;
membrane biophysics, electrophysiology of excitable cells,
membrane models; theory of bioelectrical signals,
electrocardiography, electroencephalography, electromyography;
bio-potential electrodes; bio-potential amplifiers and instrumentation
techniques, electrical and patient safety; examples of monitoring,
therapeutic and prosthetic devices. Pre-requisite: EE 311.
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• Course Objectives: To introduce basic physiology of the human
body from an electrical engineering and mathematical modeling
point of view, to provide background and understanding of
biomedical signals, measurement issues, related instrumentation
and devices.
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• Text Books:
• Introduction to Biomedical Engineering (3rd. Ed.), J.D. Enderle, and
J.D. Bronzino, 2012 (ISBN: 978-0123749796)
• Medical Instrumentation – Application and design (4th. Ed.), John G.
Webster, 2010 (ISBN: 978-0471676003)
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• Reference Materials:
• Lecture Notes
• Human Physiology, Vander, Sherman, Luciano, 2001 (ISBN: 9780072516807)
• Bioelectricity - a quantitative approach, Robert Plonsey and Roger
Barr, 2007 (ISBN: 978-0387488646)
• Sensors and Signal Conditioning, Ramon Pallas-Areny and John G.
Webster, 2000 (ISBN: 978-0471332329)
• Analysis and Application of Analog Electronic Circuits to Biomedical
Instrumentation, Robert B. Nortrop, 2003 (ISBN: 978-0849321436)
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Grading:
2 Midterm Exams
each
Class performance, homeworks, attendance, etc.
Final Exam
Laboratory work
22,5%
5%
25%
25%
IMPORTANT NOTE:
To be able to eligible for the final exam, students should take all the
midterm exams, complete the laboratory work. In addition,
the minimum average score of 25 over 100 should be obtained from the
midterm exams,
the minimum score of 25 over 100 should be obtained from the laboratory
work,
more than 50% of the lectures should be attended.
Students who do not take any one of the midterm exams or the final exam
or do not complete their laboratory work will be graded with “NA”.
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• Students who are graded with “NA” will not be eligible for the RESIT EXAM.3
Biomedical Engineering
• Biomedical Engineering is a discipline which
develops and applies engineering science and
technology for the purpose of:
– gaining further understanding of life-processes,
and
– providing better health care.
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Scope of Biomedical Engineering
Biomedical Engineering has now reached a stage of
development at which several specific study areas can
be identified to be unique to Biomedical Engineering and
to define its scope.
These areas can be gathered in three groups:
• Biomedical Engineering: Basic Biomedical Engineering
which consists of the activities in academic spheres.
• Medical Engineering: Applied Biomedical Engineering
in the industrial world.
• Clinical Engineering: Applied Biomedical Engineering
in hospitals and other health care centers.
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Biomedical Engineering
• It demands new developments in methodology
and theory of engineering as it faces the more
complex and peculiar aspects of a non-manmade object of study, the living organism.
• Two important approaches of BME to study life
processes:
– systems approach
– quantitative approach
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Systems approach to biology :
• BME draws heavily from the systems approach of
engineering.
• In system science, a system is partitioned into its constituent
sub-systems. The dynamic interactions of these subsystems are then investigated using a highly developed
mathematical formalism.
• Furthermore, the environmental factors which alter the
system's behavior are also incorporated into this formalism.
• The methodology of system science is a powerful tool to
identify and conceptualize the inner-workings and the
behavior of the system under study.
• To achieve its goal, system science utilizes the empirical
evidence about the input-output or stimulus-response
behavior of the system. As such, it requires specific designs
for experimentation.
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Quantitative approach to biology
• Parallel to the development in biology, research in Life
Sciences and the delivering of Health Care is becoming
more precise and quantitative.
• It is now common practice to apply to biological data the
techniques of signal processing and statistical analysis.
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spectral analysis,
filtering,
time-series analysis,
smoothing and averaging,
establishing probability distributions and correlations,
statistical factor analysis,
statistical hypothesis testing, etc.
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What kind of activities is a BME
involved in?
• Must be able to design and conduct biological
experiments.
• Must be able to utilize numerical techniques, modeling
and simulation methods to design experiments and to
extract the desired information from the data.
• Must know the pitfalls of the techniques he uses and
must be alert and knowledgeable to alter and develop
his mathematical methods.
• Must be a researcher who understands and uses the
language of both biology and engineering.
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Medical Engineering
• Applies and develops engineering methodology and
technology for the purpose of achieving advancement in
the delivery of health care, particularly in research,
design, and development in areas such as
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biomaterials,
transducers,
monitoring and measuring devices,
diagnostic instruments,
therapeutic instruments
artificial organs and aids
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Examples
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Bio-materials: Mechanical and other properties of bio-materials and implant
materials, dentistry.
Biomedical transducers for measurement of biopotentials, pH, pCO2, pO2,
force, displacement, pressure, flow, temperature, and impedance.
Biomedical instrument systems such as
– Electrocardiography and other electrophysiological instruments (EEG, ECG, etc.)
– Cardiac emergency equipment such as heart monitors and defibrillators
– Blood instrumentation such as automated blood metabolite determiners, clotting
time measurements, etc.
– Breathing and respiratory apparatus such as the artificial ventilator, heart-lung
machine, spirometer, etc.
– Physical therapy devices such as the electrostimulators, heaters, diasthermies
and sonic therapy devices
– Diagnostic equipment such as Ultrasonography, X-ray machines, tomography,
radioisotope and nuclear medicine devices
– Artificial organs such as the heart valves, artificial blood vessels and grafts,
artificial kidney, artificial pancreas, etc.
– Orthopedic and prosthetic devices
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These areas of application necessitate knowledge in
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mechanical,
chemical engineering,
electronics,
bio-materials - to name just the more important ones.
They also require the understanding of some properties of life systems.
– non-invasive sensing and testing within human tolerances.
– design in and for living systems must be within strict safety standards and
regulations that far exceed the constraints imposed on other types of designs.
Viewed in terms of potential consequences, the margin for error is very slim.
– Concepts like "bio-compatible", "host rejection", "bio-degradable", or even "hypoallergenic" is certainly unconventional in terms of traditional design criteria.
– Thus the Biomedical Engineer is faced with an entirely different point of view
towards the design process, one that introduces a whole new set of rules.
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Medical Engineer, therefore, is a designer who knows the needs of the
medical field, realizes the constraints imposed on his designs and who
follows the up-to-date know-how of engineering technology.
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Clinical Engineering
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In clinical engineering, engineering concepts and technology are used to
improve health care delivery systems in hospitals, clinics and other units.
The goal is to achieve the technically the best, the most economical and the
safest patient care. A typical clinical or biomedical engineering department
at a hospital may be involved in the following activities:
– Equipment and health care delivery system specification, evaluation and
incoming inspection.
– Maintenance management and preventive maintenance
– Repairs and equipment control
– Equipment and facility electrical safety testing
– Interpreting, complying with and suggesting standards
– Drafting policies and procedures, conducting in-service training, collecting
equipment documentation
– Interacting with medical staff
– Consulting
– Developing ideas and software for the computerized healthcare delivery systems
such as medical records, computer archive systems, patient interviews, mass
screening, automated laboratories.
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Clinical Engineering
• The clinical engineer, in order to succeed in the above duties, must
be knowledgeable in
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health-care delivery systems,
hospital organization structure,
economics of health-care codes,
standards and regulations of the hospital world,
hospital information flow and handling, and equipment acquisition
besides the more traditional field work such as maintenance repair.
• Another field into which the clinical engineer may indulge is
rehabilitation. Rather than being an indirect technical support for the
physician and nurse, he may be involved in providing technical
support directly to the patient. In a hospital's therapy and
rehabilitation department he may be concerned with
– improving equipment usage,
– consulting in technical aspects.
This kind of work is coming to be recognized as a separate field and
named rehabilitation engineering.
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Examples of electrical engineering
contributions to problems in health care
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Electronics
Power
Communication
Control
Computers
Biomedical engineering
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(Taken from Prof. Webster’s
lecture notes)
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What can Electronics contribute to health
care?
The artificial cardiac pacemaker requires
highly miniaturized electronics
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The artificial cardiac
pacemaker uses an
accelerometer to speed up
heart rate during
movement.
If the electrode senses
normal pacing it inhibits
artificial pacing.
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What can power engineers contribute to health care?
• For those with no hearing, in a cochlear implant, a 24 electrode
probe stimulates the auditory nerve.
• A coil outside the skin transmits adequate power to a coil under
the skin.
• Each electrode stimulates nerves responding to a different
frequency.
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What can communication engineers contribute to health
care?
The cochlear implant speech processor divides signals
from a microphone into different frequency bands.
Signals then stimulate corresponding auditory nerves.
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What can Electronics contribute to health care?
The Medtronic LIFEPAK 500 Automatic External Defibrillator (AED),
measures the electrocardiogram using only 2 electrodes. It then
decides if the rhythm is normal or in ventricular fibrillation.
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What can Electronics contribute to health care?
Conventional electrocardiogram requires 3 electrodes to prevent
excessive interference from the power lines. If we could use only 2
electrodes it would save millions of electrodes.
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What can Electronics and Communication contribute to health care?
Patients with Parkinson’s disease may benefit from deep brain
stimulation. A 4-electrode probe in the brain is electrically stimulated to
release chemicals that change a patient who can hardly walk to a person
who walks normally.
What can Electronics and Communication contribute to health care?
Brain signals from patients who cannot move or speak
can control computer input so they can communicate
with the external world.
What can Microwaves contribute to health care?
• Hyperthermia is a cancer treatment that involves heating tumor cells
within the body. Elevating the temperature of tumor cells results in cell
membrane damage, which, in turn, leads to the destruction of the
cancer cells. Today hyperthermia is used as an adjunct to radiation
therapy and chemotherapy.
• Hyperthermia treatment of cancer requires directing a carefully
controlled dose of heat to the cancerous tumor and surrounding body
tissue. Cancerous tissues can be destroyed at exposure to a
temperature of about 108 °F for an hour. This high heat must be used
wisely—too little heat and the cancer will not be killed. However, if too
much heat misses the tumor target, the skin or other healthy tissues
could be burned.
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What can Microwaves contribute to health care?
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In addition to treating tumors, microwaves
show promise in detecting and locating them
by acting as a sort of radar for your body. A
breast tumor, for example, has a much
higher water content than the surrounding
healthy tissue. Working in much the same
way as a radar system, microwaves can be
bounced off potential tumors and provide
information about size and consistency. This
diagnostic tool can be used in conjunction
with more traditional x-raying techniques,
such as mammography, and may even
prove more effective at detecting tumors
earlier. While more work remains to be done,
this use of microwaves seems very
promising.
Beginning in 2001, microwaves were also
used to treat atrial fibrillation, where the
chambers of the heart beat irregularly. By
inserting a special probe through the arteries
leading to the heart, a surgeon can heat the
irregularly beating muscle, causing the heart
to return to normal beating.
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What can Communication systems contribute to health care?
A firefighter may become disabled in a burning building. Sensors in
chest band will identify heart R wave occurrences, breathing patterns,
and monitor firefighter motion. This information will be transmitted
wirelessly to an outside command center where it will be displayed.
Cessation of signals will show the firefighter to be in peril, triggering an
alarm.
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What can Communications contribute to health care?
An accelerometer can determine if a firefighter is
vertical or horizontal. Chart shows a firefighter that
would be vertical at 0 g and horizontal at  1 g.
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