Post on 30-Dec-2015
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FYS4250 Fysisk institutt - Rikshospitalet
Image: Grimnes, Høgetveit. Biomedical Engineering Education & Advanced Bioengineering Learning: Interdisciplinary Concepts.
”A sensor is a mediator able to convert one or more measurands or physical variables into an equivalent signal variable of another type of quantity within a frame of a given unity”
Pallàs-Areny, Webster, Sensors 2001
What is a sensor?
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Image: Grimnes-Høgetveit. Biomedical Engineering Education & Advanced Bioengineering Learning: Interdisciplinary Concepts.
- Sensor system: ”comprises the total signal path from the measurand to the observer and includes all sensing, conditioning and real-time processing elements in the path”
- Electrode: ” An electrode is an electrochemical cell converting charge carriers from ions to electrons or vice versa. An electrode is only a half-sensor in the way that two electrodes are necessary in order to apply a current or read a potential difference in living tissue”
- Probe: A ”probe is a broader concept than a sensor. A probe is often comprising multiparameter sensors (e.g. temperature) and may be held by the operator and be equipped with switches and level adjustment facilities. Example: Ultrasound probe”
Source: Grimnes-Høgetveit. Biomedical Engineering Education & Advanced Bioengineering Learning: Interdisciplinary Concepts.
More definitions....
Pressure transducerand Wheatstone bridge
Image: Grimnes-Høgetveit. Biomedical Engineering Education & Advanced Bioengineering Learning: Interdisciplinary Concepts.
FYS4250 Fysisk institutt - Rikshospitalet
Piezoelectric
transducer
C=εA/x
FYS4250 Fysisk institutt - Rikshospitalet
Photomultipliers
Membrane potential
Nernst equation for potassium K (Nor - Kalium):
][][
][log5.61
][
][ln 10 mV
K
K
K
K
nF
RTE
i
o
i
oK
across a cell membrane with active channels pumping K ions into the cell.
Dipolesin theaxon
Neural velocity
The heart
Atrioventricular-block
Ectopic beat
Tachycardiaflutter=
increased regular
frequency
flimmer (norsk) =fibrillation (eng) =
= uregelmessig rytme
Ischemia
Metal /electrolyte
=electron /
iontransitions
Ag / AgCl Non-polarizable electrode
Electrode polarization +
skin + deeper layer
Stimulation electrodes
FYS4250 Fysisk institutt - Rikshospitalet
FYS4250 Fysisk institutt - Rikshospitalet
Einthoven triangle
FYS4250 Fysisk institutt - Rikshospitalet
Wilson central terminal
FYS4250 Fysisk institutt - Rikshospitalet
Augmented leads
FYS4250 Fysisk institutt - Rikshospitalet
”Driven right leg”
FYS4250 Fysisk institutt - Rikshospitalet
Biopotentail amplifiers
FYS4250 Fysisk institutt - Rikshospitalet
FYS4250 Fysisk institutt - Rikshospitalet
FYS4250 Fysisk institutt - Rikshospitalet
The circulatorysystem
FYS4250 Fysisk institutt - Rikshospitalet
Typical blood pressures
FYS4250 Fysisk institutt - Rikshospitalet
Invasive blood pressure measurement
FYS4250 Fysisk institutt - Rikshospitalet
Harmonic analysis, Fourier
FYS4250 Fysisk institutt - Rikshospitalet
Heart sounds
FYS4250 Fysisk institutt - Rikshospitalet
Stethoscopes, spektrogram
FYS4250 Fysisk institutt - Rikshospitalet
Non-invasive blood pressure
FYS4250 Fysisk institutt - Rikshospitalet
Ultrasound measurement
FYS4250 Fysisk institutt - Rikshospitalet
Bloodpressure, oscillometric
FYS4250 Fysisk institutt - Rikshospitalet
Non-contact tonometry
Indicator-dilution method
1
0
)(t
dttC
mF
Elektromagnetic flowmeter
BLue
Electromagnetic flowmeter waveforms
Quadrature-suppression flowm.
Plethysmography
Plethysmography curve
Figure 1 Airways with
larynx, trachea, bronchi and
alveoles
Figure 2
Lung volume parameters
Equation 1 Compliance C = ΔV / ΔP [L/Pa, L/cmH2O]
Equation 2 Poiseuille4
8
r
LR
[Pa/m3/s = pressure / flow rate]
Figure 6
Laplace cylinder model
P=T/r
Figure 10
Rebreathing circle
with one-directional valves 1 and 2
Figure 13 IR absorption spectra for some anaesthetic agent vapours.
Datex Ohmeda Division, Instrumentarium Corporation
Figure 14 Multigas spectrophotometric gas analyzer
with rotating filter wheel
pH-measurement
pCO2 (Severinghaus) electrode
pO2 (Clark) electrode
Fluorescent dye sensor
pH-sensitive dyes
Pulsoxymetry light absorption