Welcome to BMEN 321 Biomedical Electronics Prof' Ken Meissner Zachry 335O 4580180

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Welcome to BMEN 321Biomedical
ElectronicsProf. Ken MeissnerZachry
335O458-0180
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Course Info

• Meet 1110am - 1225pm in Jack E. Brown
  Building, Room 108 (apparently you know this
  since you are here)
• Office Hours
• Tuesday/Thursday 130pm 230pm
• You are welcome to come in whenever the door is
  open

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Grading

• Three Exams 25 each
• Quizzes 15 (you will drop one quiz)
• Homework 10
• There are no pre-defined letter grade boundaries.
  Letter grades will be assigned at the end of the
  semester based on the distribution of the total
  scores.

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Schedule/Class

• See handout for detailed schedule
• Each class will consist of 50-60 minutes of
  lectureI get tired after that long
• I will bring in some demos that relate to the
  material presented in class

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Course Objectives

• Learn
• Basic Circuit Analysis (review)
• Biopotentials and Transducers
• Computer Interface for Instrumentation
• Operational Amplifiers
• Op-Amp Circuits
• Basic Filters
• Op-Amp Filters
• Basic electronic components
• Diodes, Transistors
• Lockin Detection
• At the end of the course you should be able to
  design and build basic electronic instrumentation
  for Medical use.

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What is a Medical Instrument?

• Definition Device including instrument, tool,
  machine or implant for monitoring or sensing,
  diagnostics, or therapeutics or surgery

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Types of Instruments Sensing/Monitoring

• A device that measures physiological parameter(s)
  such as pressure, flow, pulse, analyte
  concentration, or temperature
• Examples
• Thermometer
• Blood Pressure
• Pulse Oximeter
• Glucose Monitor

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Types of Instruments Diagnostic

• A device that gathers information leading to the
  identification of a disease or disorder
• Examples
• Imaging (X-Ray, CT, MRI, PET)
• Chemical Analyzers (Clinical Chemistry)
• Optical Diagnostics DNA MicroArrays

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Types of Instruments Therapeutic

• A device that is used to treat a disease or
  disorder.
• Examples include
• Simple crutch
• Drug delivery
• Surgical Tools (scalpel, laser)
• Orthopedic implants
• Soft tissue implants
• Pacemakers

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Basic Generic Instrument
Sensing/ Monitoring
Biological System
Transducer
Signal Processor
Diagnosis
Therapeutics/ Surgery
Feedback
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Transducer

• Sensor plus pre-processing/ amplifier
• Transform physiological signal into a form that
  the signal processor can read
• Must have good sensitivity and accuracy
• Should have low noise and sufficient dynamic
  range
• Must be effective and stable across entire
  physiological range
• Sensor can range from nanoscale structures to
  room-sized devices

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Signal Processor

• Can be as simple as driving a needle meter or a
  level on a scale OR as complex as a computer
  reconstructing a three dimensional image from
  thousands of pictures
• The use of electronic signal processors has
  enabled numerous advances in the past four
  decades
• Heavy duty mathematical processing is becoming
  the norm

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Feedback

• Traditionally involved a physician or therapist
  observing the patient
• More recently feedback occurs in a closed loop
  with sensor(s) and/or monitor(s)
• FDA is very careful to maintain human involvement
  in important decision processes

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Bottom Line

• The fundamental purpose of a medical instrument
  is to enhance the capabilities of human beings to
  help themselves and each other.

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Historical Perspective Use of Senses

• Touch/Hearing used to quantify temperature, pulse
  rate, and heart beat as well as therapy
• Stethoscope invented in 1819 to enhance sounds
  (shown Cammann Stethoscope circa 1880)
• Current research on use of acoustic transducer
  for stenosis diagnostics

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Historical Perspective Use of Senses

• Sight used on both the inside
• and outside of the body
• Candles and magnifiers used
• Ophthalmoscope used to probe
• ears, eyes and nose
• Endoscope probes deeper in
• body where there is no light
• Current developments include
• the use of light outside the
• visible spectrum for imaging

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Historical Perspective Use of Senses

• Taste and Smell have been
• used to diagnose body fluids
• and wounds
• Urine of diabetics tastes sweet
• Clinical chemistry labs provide
• sample analysis in hospitals
• Current developments include
• electronic nose/taste sensors
• with arrays of individual sensors

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Historical Perspective 20th Century

• 1903 ECG heart diagnostic
• 1924 EEG brain waves
• 1928 ESU cauterizing scalpel
• 1928 Iron Lung respiration assist
• 1936 Nuclear Medicine
• 1956 Defibrillation
• 1957 Pacemaker (1960 implantable)

• 1957 Ultrasound Imaging (anatomical imaging)
• 1970 CT Scanner (anatomical imaging)
• 1975 Inter aortic balloon pump
• 1982 MRI (anatomical imaging)
• 1984 Artificial Heart
• 1990s PET - use radio isotopes (physiological
  imaging)

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Cambridge Electrocardiograph 1912
Torture or early medical Device?????
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Case Study Smart Bed

• The Smart Bed Concept was Developed in Response
  to the Need for Non-Intrusive Automated
  Monitoring of Patient Movement and Vital Signs
• A long gauge length integrating fiber optic
  sensor is integrated into a standard patient bed
  beneath the mattress.
• Patient physical movement and movement due to
  respiration and heartbeat perturb the fiber.
• Modulation of the optical signal due to the
  integrated mechanical perturbation of the fiber
  is processed to provide the required information.

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Sedentary Elderly Become Vulnerable to Extremely
Painful Conditions Due to Lack of Mobility
Sedentary patients in nursing homes require
assisted movement to prevent the occurrence of
pressure induced ulcers (bed sores). If patient
movement can be remotely monitored, optimum
schedules for assisted movement can be
devised. The potential market for such a
capability is in the multi-B range.
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W.B. Spillman et al, Statistical mode sensor for
fiber optic vibration sensing applications,
Applied Optics 28, No. 15, pp. 3166-3176, 1989.
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P.R. Herczfeld et al, An embedded fiber optic
sensor utilizing the modal power distribution
technique, J. Opt. Lett. 15, No. 21, pp.
1242-1244, 1990.
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Rested Students.Happy Students
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The STM Sensor Demonstrated the Ability to Detect
Patient Movement and Respiration Rate
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The HOME Sensor Demonstrated the Ability to
Detect Patient Movement, Respiration Rate and
Heart Rate
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The System Uses Cost Effective Off-the-Shelf
Hardware
nurse wearing RF ID tag
STM sensor
data is processed and activity is logged by a
central computer at the nurses station
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Minimal Engineering Development was Required to
Create the Wireless System
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Homework

• Due Tuesday 9/5
• Chapter 1 2, 8, 23, 25
• Use the web to investigate the history of a
  medical instrument. BRIEFLY summarize the
  history.