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Biomedical imaging and sensing > Biomedical imaging and sensing > Flashcards

Biomedical imaging and sensing Flashcards

1
Q

when was the first x-ray taken and by who? What award did he get and when?

A

1895 by Wilhelm Conard Roentgent and he was awarded a noble prize in 1901 for doing so.

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2
Q

what is the relationship between energy and wavelength?

A

as wavelength increases, energy decreases.

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3
Q

arrange the main rays from lowest to highest energy.

A

radiowaves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma rays.

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4
Q

what is the definition of an image?

A

is the sum of the attenuation coefficient of the materials present in the body along the x-ray path

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5
Q

what is the oldest and most widely imaging used?

A

2D projection imaging

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6
Q

what are the ingredients included for x-ray production

A

-a source of electrons (tungsten), - a means of accelerating the electrons at high speed, - target material (tungsten)

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7
Q

what happens when x-rays interact with materials?

A

Transmission where x-rays penetrate through material.
Scattering where x-rays get deflected from their original direction.
Absorption where x-rays get absorbed by material.

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8
Q

when does contrast in x-rays happen?

A

when x-rays interact with different types of tissues in the body.

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9
Q

what is the difference between the direct and indirect conversion of x-rays?

A

direct conversion: the x-ray energy is captured and turned into an electrical charge by the same component. indirect conversion: a specific material captures x-rays and turns them into a different form of energy (visible light), this energy is then converted to electric charge.

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10
Q

what are the components in an x-ray source?

A

vacuum (glass enclosure), rotor, anode and cathode

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11
Q

what are the advantages of x-ray imaging?

A

Cheap
Easy to use

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12
Q

what are the disadvantages of x-ray imaging?

A

Are in 2D
lack sufficient detail because radiation exposure will happen if they get focused.

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13
Q

what are the risk factors of using x-ray imaging?

A

x-rays leave small residues of radiation and accumulated radiation over a lifetime can lead to cancer.
X-rays cause electrons to be in motion therefore ionize water molecules and create free radicals which damage biological targets (DNA).
X-rays ionize DNA molecules.

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14
Q

how to prevent X-ray risk factors?

A

A lead vest is used to absorb radiation.

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15
Q

What happens after the RF pulse is turned off?

A

Excited nuclei go through a relaxation phase

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16
Q

When does 2D fourier transform equation happen?

A

When a wave over time function is converted into a frequency function

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17
Q

What is lowpass filtering?

A

Is the type of frequency domain filter that is used for smoothing the image.

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18
Q

What is highpass filtering?

A

Is the type of frequency domain filter that is used for edge enhancement.

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19
Q

How are edges identified on an image?

A

An edge can be identified on an image as (an abrupt) change in the greyscale.

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20
Q

What are ROIs?

A

Regions of interest.

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21
Q

What is the major application of image analysis?

A

Identification of regions of interest (ROIs) segmentation of ROIs.

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22
Q

How to make regions of interest ROIs more distinct?

A

Sharpen their edges.

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23
Q

How to detect edges?

A

By locating abrupt changes in the intensity profile.

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24
Q

What masks does Sobel operator include?

A

1- a column mask (Gy).
2- a row mask (Gx).

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25
Q

What happens to the frequency, velocity, and wavelength when a wave passes from one medium to the other?

A

The frequency stays constant but since the velocity changes therefore the wavelength changes too.

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26
Q

What is refraction?

A

The bending of waves from one medium to the other.

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27
Q

What are the disadvantages of ultrasound?

A

Resolution is limited
Strongly deflected on passing from tissue to gas or vice versa which means it cannot be used for areas of the body containing gas like the lung and the digestive system.
It does not pass through bones and therefore it cannot be used for fractures.

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28
Q

What lights do emission filters reject?

A

Any laser light that is reflected or scattered by a sample

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29
Q

What does optical imaging do?

A

Utilize ultraviolet, visible, and near-infrared light to produce images for biomedical applications.

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30
Q

What are sensors?

A

Devices that detect or measure a physical/chemical property and record, indicate or respond to it.

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31
Q

What is a transducer?

A

A device that converts an observed change (physical or chemical) into a measurable signal.

32
Q

What are the three types of sensors?

A

A physical sensor which measures physical quantities such as temperature, pressure and electricity.
A chemical sensor which measures chemicals such as blood-oxygen sensors.
Biosensors which recognise biological elements such as glucose sensors.

33
Q

What is response time?

A

The time required for the output to rise to a specified percentage (generally 90%) of its final value.

34
Q

What is detection limit?

A

Is the lowest value of measurand that can be detected by a sensor.

35
Q

What are the two main components of optical fibres?

A

Cladding
Core.

36
Q

Why is refractive index of core larger than refractive index of cladding?

A

So that the light bends.

37
Q

What is the power of nanometer?

A

10 to the minus 9.

38
Q

What is the power of a micrometre?

A

10 to the minus 6.

39
Q

Give examples of first-order operators.

A

Sobel, Canny, Roberts, and Prewitt.

40
Q

Give examples of second-order operators.

A

Laplacian.

41
Q

What are the characteristics of H2O2?

A
  • A strong oxidizer.
  • Unstable and should be stored in a cold and dark environment.
  • Corrosive meaning it can damage the skin.
42
Q

What is Prussian blue used for ?

A

It is used as an alternative to the peroxidase for H2O2

43
Q

What are the areas of interest in medical thermometry?

A
  • core body temperature in medical thermometry.
  • blood temperature.
44
Q

what methods does core body temperature use?

A

routine diagnostic method.

45
Q

what are the disadvantages of using the traditional Mercury thermometer?

A
  • slow operation
  • difficult to read and register the results
  • can easily be broken and poison the environment.
46
Q

what are the advantages of using the traditional Mercury thermometer?

A

application is widespread due to low cost

47
Q

what does the electronic thermometer contain?

A

a thermistor as a temperature-sensing element

48
Q

what are the positive and negative aspects of electronic thermometers?

A
  • fast
  • easy to read and register the results
  • safe for the environment.
  • require a battery to work
  • expensive
49
Q

what are the requirements for using a microwave or radio frequency oblation for cancer treatment?

A
  • temperature requirement 35-50 celsius or 0.1 celsius
  • fibre-optic sensor has to be a non-metallic sensor.
50
Q

what are the consequences of using conventional temperature sensors when using a microwave or radiofrequency oblation for cancer treatment?

A

Thermocouples or thermistors can perturb the incident electromagnetic field and lead to localised heating spots or sensing errors.

51
Q

What do fibre optics do?

A

Fibre optics utilise the phenomenon of total internal reflection to send high speed light signals over large distances.

52
Q

what is total internal reflection in physics?

A

in physics, total internal reflection is the phenomenon in which waves arriving at the interface from one medium to another are not refracted into the second medium but completely reflected back into the first medium.

53
Q

what does increasing the twisting frequency of wires do?

A

increasing the twisting frequency of wires can reduce the crosstalk influence in unshielded cable pairs and prevents interference crossover between twisted cable pairs.

54
Q

what is crosstalk?

A

is the unwanted transfer of signals between communication channels.

55
Q

how is crosstalk minimised?

A

by using twisted pairs of cables.

56
Q

what are the advantages that fibre optic systems have over electrical transmission media?

A

higher data rate
less susceptible to noise
have a longer transmission system

57
Q

is pressure response time quicker or signal response time

A

pressure response time is quicker than the signal response time

58
Q

give an example of a sensor that gives a chemical response.

A

PH paper gives the degree of acidity due to change i homeostasis.

59
Q

give examples of signals from sensors.

A

colour changes
electrical responses

60
Q

give examples of sensors and briefly describe what they do

A

stethoscopes are acoustic medical devices used to listen to lung and heart sounds
thermometer
blood pressure device
EEG which is a neural biopotential electroencephalogram that records electrical activity in the brain
pulse oximeter for oxygen saturation
finger picker to test blood sugar levels

61
Q

what do static characteristics describe?

A

the relationship between the output signal and the measurand

62
Q

what is sensitivity?

A

the slope of the static characteristics function
sensitivity = change in instrument reading over the change in measurand

63
Q

what is FSO?

A

full scale output
the maximum (or nominal / existing) output signal

64
Q

what is linearity?

A

closeness of a sensor calibration curve to a specified straight line

65
Q

what is hysteresis?

A

the maximum difference in output when increasing and then decreasing measurand
change is H over FSO

66
Q

what is detection limit?

A

the lowest value of measurand that can be detected by a sensor

67
Q

what is resolution?

A

the increment in the output

68
Q

what is repeatability (reproducibility)?

A

the ability of a sensor to reproduce output readings

69
Q

what is zero output (offset)?

A

the output when the zero measurand in applied

70
Q

what is zero drift or shift?

A

a change in the zero measurand output under specified conditons

71
Q

what is sensitivity shift?

A

a change in the slope of the calibration curve

72
Q

what is response time?

A

the time required for the output to rise to a specified percentage (generally 90%) of its final value

73
Q

what is selectivity?

A

the suppression of the environment interference

74
Q

what are the two elements of sensor structures?

A

sensing effect: the interaction between the environment and the sensing material which alters the material property.
transduction mechanism: converts the material property charge into a useful signal.

75
Q

what are some of the sensor structures?

A

impedance-type sensors
electrochemical cells
fibre optic sensors

76
Q

what do impedance type sensors do?

A

they follow the sensing phenomena with capacitance, resistance and/or inductance change.

Biomedical imaging and sensing (1 decks)

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