Download Measurement errors

Version 08/2009
A short orientation about the course
FYS 4250
Biomedical Instrumentation
Timetable p.2
Topics p.3
Required reading p.4-5
Course structure p.6
Terminology, p.7
Problems, p.8-15
Project work p.16-17
Measurement errors p.18
Fra BBB:
Migration and diffusion p.28-30
Electrical safety p.398-409
Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
1
Timetable FYS 4250
Tuesday
Thursday
Tuesday
Thursday
Tuesday
Thursday
Tuesday
Thursday
Tuesday
Thursday
Tuesday
Thursday
Tuesday
Thursday
Tuesday
Thursday
Tuesday
Thursday
Tuesday
Thursday
Tuesday
Thursday
Tuesday
Thursday
Tuesday
Thursday
Tuesday
Thursday
23. August
25.
30.
1. September.
6.
8.
13.
15.
20.
22.
27.
29.
4. October
6.
11.
13.
18.
20.
25.
27.
1. November
3.
8.
10.
15.
17.
22.
24.
Exam date
Friday
2.dec
Jan Olav Høgetveit Utskrift: 18.06.17
Autumn 2011
Chapter
1
2-3
3-4
4
5
6
7
8
9
10
11
12 Rad
12 Nukl
12 MR
12 UL
13 Card
13 Anest
13 Sur
14
Imp. top
rep
Loc
Fys
Fys
Fys
Fys
Fys
Fys
Fys
Fys
Fys
Fys
Fys
Fys
Fys
Fys
Fys
RH
RH
Fys
Fys
Fys
Fys
14:30, 3h
?
FYS 4250 Orientation 2011
Project work
Project subjects
Subject selection
Handing in
Last day
EXAMINATION
2
COURSE DESCRIPTION
FYS 4250 Biomedical instrumentation
10 study points
Contents: Instrumentation principles, regulation systems, sensors, amplifiers,
digital signal processing. Diagnostic and therapeutic equipment.
Electrophysiological methods like ECG, EEG, EMG, defibrillators and
pacemakers. Measuring methods for pressure, flow, ventilation and circulation,
monitoring. Microbiology and sterilization of equipment. Clinical chemical
analyzing principles. Imaging techniques, x-ray, nuclear medical, ultrasound,
magnetic resonance. Digital pictures, supporting equipment like dialysis
machines, heart-lung machines, anesthesia workstations, surgical
instrumentation with cryo, diathermia and laser. Medical information, patient
safety.
Goals: That the students should have a good knowledge of modern medical
instrumentation and the physical and medical principles basis for this
instrumentation.
Preferred basis knowledge: FYS1120 – Electromagnetism and FYS1210
Elementary electronics with project works.
Lectures: 4 hours each week in one semester (autumn).
Exam: Written or oral. One has to pass one project work.
Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
3
Version: 01/2010
REQUIRED READING
FYS4250 BIOMEDICAL INSTRUMENTATION
JOHN WEBSTER:
EDITION (2009)
MEDICAL
INSTRUMENTATION,
FOURTH
SVERRE GRIMNES, ØRJAN MARTINSEN: BIOIMPEDANCE AND
BIOELECTRICITY BASICS (2008).
Chapter 2.4.2: Migration and diffusion
Chapter 9.17: Electrical Safety, Hazards.
My e-mail address: [email protected]
Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
4
COURSE STRUCTURE:
FYS 4250 Biomedical instrumentation
There are principally two different approaches to biomedical instrumentation:
1)
A scientific starting point and classification. Different physical principles and
technologies are used as a basis for medical instruments.
2)
A medical starting point and classification. The human body and medical situation
with a need of diagnosis, therapy and supportive treatment is used as a starting point
for medical instrumentation with the necessary physical and technological principles.
This course has previously been based on Bertil Jacobsons book "Medicin och teknik" which
uses method number 2. However, this book was available in Swedish only, and was
withdrawn from the market in 2005, which has led to Websters ”Medical Instrumentation”
book which the course is now based on.
However, I am aiming at a basis in the middle between the medical and the scientific fields of
interest. My basic intention is first of all to make the student able to understand the concepts
of medical instrumentation, not the details. (The details may be learned when the concepts are
understood).
Jan Olav Høgetveit
Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
ver. 01/2011
5
ver. 01/2010
Terminology
Physics - Technology
Is scientific subject areas. The physics in this course is focused on how to use the physical
principles to design medical instruments.
Biophysics
Is the part of physics studying the life processes.
Medical instrumentation - (clinical engineering)
Is about instrumentation in human medicine, especially the hospital based instrumentation.
The main focus is the very special demands for this type of instruments
Medical technology
Is the science of how to design, produce and market medical equipment.
Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
6
PROBLEMS CHAPTER 1
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What is the difference between modifying and interfering inputs? 2
examples on each type.
What is a 1.order instrument? What characterize it?
Draw a most simplified servo diagram equivalent to eq.(1.1)
What is the normal measuring range of venous blood pressure? Should
small negative values be included?
What is FDA? What is the 510(k) process?
PROBLEMS CHAPTER 2
What is a strain gage? How is eq(2.1) used?
What is a plethysmograph?
Capacitive displacement transducer, how is eq(2.8) relevant? What could
be an interfering input?
Advantages and disadvantages of thermocouple temperature measuring
method.
A black body emitter at 37 oC, at which wavelength in the infrared
spectrum is the peak emmittance?
PROBLEMS CHAPTER 3
How many input terminals have a differential input port?
What is the input resistance of an inverting amplifier? And a noninverting?
Is the complete circuit of fig.3.5 an instrumentation amplifier? What is a
common mode input signal for such an amplifier system?
What is a phase sensitive demodulator and why are they so important in
measuring systems?
PROBLEMS CHAPTER 4
A few words about the Nernst equation and the cell membrane and its
permeability.
What is an action potential?
What is saltatory conduction?
What is an H-wave?
Describe the heart dipole and the surface potentials
What is a 1.degree heart block?
What is the cortex?
Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
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What are delta-waves?
PROBLEMS CHAPTER 5
Define an electrode. Is it a sensor?
What is a half-cell potential?
What is polarization? And electrode polarization impedance?
What is a polarizable electrode?
Fig.5.8 shows a series coupled model of a skin surface electrode system.
Which of the components are usually the dominant parts of the total
impedance?
How could a sterile wire be invasively positioned in tissue?
How could an intracellular microelectrode be made?
PROBLEMS CHAPTER 6
Does the book define the cardiac vector as a current dipole?
What is a lead?
What is a lead vector?
What is an unipolar lead?
What is Wilson’s central terminal?
If there is no difference in electrode/skin impedance Z1 and Z2, do we
have zero noise voltage according to eq.6.5? Explain.
What is the purpose of the driven-right-leg circuit of fig.6.15?
What is the purpose of the 1uF capacitor in fig.6.18?
PROBLEMS CHAPTER 7
Is the systolic blood pressure larger in the left ventricle than the right?
Do the Fourier harmonic components shown on fig.7.6 have the same
phase relationships?
What is compliance?
What can be done to increase the natural frequency of a catheter
measuring system?
To test a catheter blood pressure measuring system, how can a step
response be measured?
What is the Korotkoff system? What is the oscillometric system?
Indicate some source of measurement errors in the non-invasive system
shown on fig.7.20
Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
8
PROBLEMS CHAPTER 8
1.
2.
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The most important blood flow measuring principles?
Does the electromagnetic flowmeter measure maximum or mean laminar
blood velocity?
Can the transit time ultrasound flowmeter be used in saline, or must it be
blood?
Write down the Doppler shift equation.
What is the effect of the arterial occlusion cuff in fig.8.15?
What are the problems with the two electrode impedance
plethysmography?
PROBLEMS CHAPTER 9
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Does air contain any noble gas?
What is tidal volume?
What is the relationship between pressure drop, gas flow and flow
resistance?
How many mol is 66g CO2 ?
Can oxygen be a liquid at room temperature?
What is the difference between mainstream and side stream sampling?
Can oxygen gas concentration be measured spectrophotometrically?
Further questions at page 48 in the compendium.
1.
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PROBLEMS CHAPTER 10
What is the oxygen dissociation curve?
What is the sensitive membrane in a usual pH-electrode?
What is a Severinghaus electrode?
What is a Clark electrode?
Why is not a pulse oximeter influenced by venous oxygen content?
1.
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PROBLEMS CHAPTER 11
What is the difference between a flame emission and flame absorption
instruments??
What is a fluorometer?
What is a gas chromatograph?
What is a Coulter counter?
Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
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PROBLEMS CHAPTER 12 (X-ray)
What is the difference between a raster image and pixel image?
Why is the MTF of interest for characterizing an image?
What is radiography?
What is bremsstrahlung in an x-ray tube?
What is secondary radiation and why is it of interest in x-ray imaging?
PROBLEMS CHAPTER 12 (CT)
What is tomography?
Does the CT use ordinary x-rays?
How is the x-ray source and detector arranged in a CT according to the
generations?
How is the Hounsfield unit defined?
What are the two main mathematical algorithms used for image
reconstruction?
What is back projection?
5.
PROBLEMS CHAPTER 12 (MRI)
Which parameters are measured and used for image reconstruction?
Does the MRI use ordinary x-rays?
Which are the three magnetic fields used?
What is the hydrogen resonance frequency in a magnetic field of 1,5
tesla?
How can T1 be measured?
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PROBLEMS CHAPTER 12 (Nuclear medicine)
Is the basic gamma-camera tomographic?
Does the gamma camera use ordinary x-rays?
What is a collimator?
What is SPECT?
What is PET?
Indicate some basic differences between SPECT and PET techniques
1.
PROBLEMS CHAPTER 12 (Ultrasound, US)
Does the US use ordinary x-rays?
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Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
10
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Is it measuring absorption or reflection?
What is A-mode scan?
What are the main scan head technologies?
Is Doppler techniques used in imaging?
PROBLEMS CHAPTER 13
What are the medical indications for using a pacemaker?
Where are the electrodes positioned for a unipolar pacemaker?
What is TENS?
What function has the inductance in fig.13.9?
What are the advantages of the roller pump technology in a Heart-Lung
machine (Pump oxygenator)?
Mention some safety devices in a hemodialysis machine?
Can the lithotripter be used with success on all sorts of kidney stones?
Why do electrosurgery technology use high frequency currents?
Why are pulsed waveforms better for coagulation?
What are the wavelengths and power used for laser surgery?
PROBLEMS CHAPTER 14
What is let-go current level?
What are risk factors when using electricity?
What is microshock?
What is ground?
What are the main differences between European and US power line
systems
What is galvanic insulation of the patient?
What is CE-marking? Is it used by FDA?
Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
11
ver. 08/2008
FYS 4250 PROJECT WORK
Content (max 5 pages including images and references):
A specified medical equipment or technology and its medical
field of application.
Topics:
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

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Physical/technological description
The intended use of the device
Interface device/operator/patient
Sources of error and hazards
Speed of technology development (stable - unstable)
Who are you writing for?
Your fellow students participating in this course.
References:
You may write with your own words, but it is important to declare the basis of
your information and images. You have to put quotation marks around
quotations including a link to the source. Quotations without quotation marks
and source reference are a theft.
CHOOSE A TOPIC OF YOUR OWN INTEREST!
This is a list of proposals in order to give you some ideas!
1. The temperature regulation of the body with a reference to servo systems. The temperature
balance, measuring body temperature, sources of error.
2. Blood gases, measurement, sources of error
3. Henderson-Hasselbachs equation
4. Bernoulli (or Stoke or Poiseuille or Pascal) equations in medicine.
5. Medical equipment between the doctor and the patient.
6. Catheterization, hazards.
7. Measurement of blood pressure
8. Measurement of blood flow
9. Gamma-cameras
10.ECG-leads
11.Vectorcardiography
Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
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12.Bioamplifiers for electrophysical signals
13.Defibrillators
14.Resuscitations (gjenopplivning)
15.Pacemakers
16.EEG
17.EMG
18.Electrodes, biosensors
19.Positron camera
20.Blood analysis methods
21.Immunologic measurement methods
22.Flowcytometers
23.Electrical bioimpedance
24.Micro-organisms and sterilization of equipment
25.Contrast in X-ray pictures
26.Sources of X-ray radiation
27.Digital medical images
28.Tomography
29.Bone mineral scanners
30.CT
31.Ultrasound imaging
32.MR
33. Anesthesia workstations
34. Electrosurgery
35.Lasers and their medical applications
36.Cryosurgery
37.Lithotripter (nyrestensknuser)
38.Endoscopy
39.Passive implants, biocompatibility
40.Stenting
41.Electrical safety and equipment in the patient surroundings
42.Hearing aid, implants
43.Ventilators
44.Medical gases and gas monitoring
45.Heart-lung machine
46.Artificial hearts
47.Dialysis
48.Pulseoxymeters
49.Infusion pumps
Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
13
ver. 08/2008
MEASUREMENT ERRORS
Example: Non-invasive measurement of blood pressure:
In a medical measurement situation, a number of measurement errors may occur. Some of
them are listed in one of the four categories below:
1. Technical parameters
 Communication line without errors
 Scale (like . temp.dependency)
 Scale in vertical position
 Zero
2. Tissue factors
 Width of the cuff
 Clothes under the cuff
 Pressure propagation
 Compressibility
3. Metrology-parameters
 Speed of pressure release
 Digit preferences
 Hearing/training
4. Physiological parameters
 Roomtemperature/clothing
 Efforts/previous history
 Body position
 Point of measurement
 Stress/anxiety/fatigue
 Closure time cuff
Jan Olav Høgetveit Utskrift: 18.06.17
FYS 4250 Orientation 2011
14