FYS 4250 REPETITION PART 1

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