Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Diagnostic Imaging Techniques > Principles of Radiography > Flashcards

Principles of Radiography Flashcards

1
Q

List 4 properties which add to the dangers of x-rays.

A
  • Invisible
  • Painless
  • Latent effects (delay)
  • Cumulative (many small doses= large dose)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

State 5 signs of direct changes in body tissue soon after exposure.

A
  • Skin redenning/cracking
  • Blood disorders
  • Baldness
  • Cataracts
  • Digestive upset/dehydration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the term Carcinogenic effects

A

Tumours develop in exposed tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the term “genetic effects”

A

Mutations induced in the chromosomes of germ cells due to exposure of the gonads

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

List the three potential sources of radiation

A
  • Tube head
  • Primary Beam
  • Horizontal x-rays
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the term maximal permissible dose (MPD)

A

The amount of radiation to not constitute a greater risk to health than other occupations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the MPD for lens of the eye for trainees under 18 years

A

45 mSv

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

When may an RPA not be necessary within general practice

A

If the practice complies with health and safety conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

List 4 instructions regarding the care and wearing of a dosimetry badge

A
  • Wear at waist level in middle of anterior abdomen
  • Keep dry when not in use
  • Never wear badges outside veterinary practice
  • All badges to be changed at recommended time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the Local Rules

A
  • Set of instructions drawn up the Radiation Protection Advisor (includes machine/equipment information, restraint methods and precautions to take if manual restraint is necessary
  • Must include the ‘Written Systems of Work’
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Give two examples of rapidly dividing cells.

A
  • The gonads

- Foetus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

If a dosemeter is giving a reading of 0.5mSv or more what should you do?

A
  • Investigate further

- Phone for advice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the natural radiation dose received annually?

A

2.2 mSv

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Should pregnant employees be allowed to participate in radiography?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

State the main ingredient of Developer.

A

Phenidone hydroquinone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the action of Developer and name the process.

A

Converts exposed silver halide crystals to black metallic silver in a process known as REDUCTION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the ideal temperature for developer to function properly.

A

20 degrees Celsius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

State the primary function of Fixer.

A

It clears the unexposed silver halide crystals from the film

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Explain the term “tanning”

A

A process where fixer hardens the film emulsion to prevent it from being scratched when being handled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the function of accelerators within the Developer.

A

Accelerators are chemicals that increase the activity of the developer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

List the 5 basic steps of film processing

A
  1. Developing
  2. Rinsing/stop bath
  3. Fixing
  4. Rinsing
  5. Drying
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

State the function of the rinse bath.

A
  • Stops the development process
  • Rinses the developer from the film
  • Prevents carryover contamination to the fixer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Describe the methods of recognising exhausted chemicals

A
  • the colour of the developer is an indicator it turns a brown to green colour when it needs to be changed
  • underdevelopment of films
  • unlikely to be fit for use after three months
  • The fixer needs to be changed if the clearing time is greater than 2 - 3 minutes.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

State the two primary advantages of automatic processing.

A
  • Saves time and effort

- Produces a dry radiograph that is ready to interpret in a short space of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

State the 2 methods of film identification

A
  • Light marker

- pencil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the name of the substance used to top up the developer when the level falls?

A

Replenisher solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What can happen to developer if the lids is not put back on the tank during manual processing?

A

Process of oxidation which will result in underdevelopment of films

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How often should you change developer?

A

Every 3 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How long should the film be immersed in developer?

A

3-5 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How long should the film be immersed in developer?

A

3-5 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What will happen if left in the developer too long?

A

Some of the unexposed silver bromide crystals are converted to black metallic silver as well, causing uniform darkening of the film

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Name the 6 main ingredients of the developer solution?

A
  • Developing agents
  • Accelerators
  • Preservatives
  • Restrainers
  • Hardeners
  • A solvent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

The colour of the developer is an indicator that it needs to be changed, what colour does it change to?

A

-Brown to green colour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Is developer acidic or alkaline?

A

Alkaline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the main constituent of fixer?

A

Sodium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Describe the following terms:
.• Density
• Contrast

A

• Density
- The degree of blackening of the film

• Contrast
- The difference between the varying shades

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Describe the following terms:
.• Density
• Contrast

A

• Density
- The degree of blackening of the film

• Contrast
- The difference between the varying shades

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

State the two factors that determine density.

A
  • Kv

- mAS

39
Q

Name the four main faults related to processing

A
  • Underdeveloped
  • Overdeveloped
  • Overexposed
  • Underexposed
40
Q

Explain how you would differentiate using metal markers in relation to overexposure and overdevelopment of films.

A
  • OVEREXPOSURE: stays white

- OVERDEVELOPED: darkened

41
Q

If a film is described as soot and white wash what does this tell us?

A

Very high contrast, low kV: white image with a black background with a few shades of grey

42
Q

Describe a film if the kV is too low.

A

The film will appear very black and white

43
Q
  1. What does the following indicate on a x-ray film?
  • Black patches
  • Grey patches
  • White patches
  • Black tree like structure looks like lightening
A
  • Black patches – Developer splashes
  • Grey patches – Water splashes on film or chemical splashes on intensifying screens
  • White patches – Fixer splashes
  • Black tree like structure looks like lightening- Static
44
Q
  1. What does the following indicate on a x-ray film?
  • Black patches
  • Grey patches
  • White patches
  • Black tree like structure looks like lightening
A
  • Black patches – Developer splashes
  • Grey patches – Water splashes on film or chemical splashes on intensifying screens
  • White patches – Fixer splashes
  • Black tree like structure looks like lightening- Static
45
Q

Explain the production of x-rays within the tube head.

A

Within the tube head there is a Cathode –ve & Anode +ve.
The Cathode (-ve) consists of a filament made up of tungsten.
This filament is heated by an electric current which produces electrons.
These electrons are released by THERMIONIC EMISSION.
The electrons are directed by the focussing cup to the Anode.
The electrons travel at high speed across the tube from the Cathode which is negatively charged to the positively charged Anode (Target Area).
Electrons hit the target area and X-rays (1% ) and heat (99%) are produced.

46
Q

State three main differences in relation to automatic processing to manual processing.

A
  1. increase in temp
  2. rinse section is missed after developer
  3. requires more water
47
Q

Common manual film faults are described below, clearly state the cause of such faults.

  1. Yellow radiograph
  2. Air bubble
  3. Fingerprints on film
  4. Dark marks on film
  5. Grey marks on film
  6. Finger crescent
  7. Very dark and white film (high contrast)
  8. Very pale and light film : can see finger behind film
  9. Film very dark all over
A
  1. Yellow radiograph – incomplete washing of film – common during fixation
  2. Air bubble – insufficient agitation
  3. Fingerprints on film – dirty finger
  4. Dark marks on film – developer splashes on film prior to processing
  5. Grey marks on film – water splashed on film prior to processing
  6. Finger crescent – damage to the film in a rush
  7. Very dark and white film ( high contrast) – too low a Kv
  8. Very pale and light film : can see finger behind film – underdeveloped
  9. Film very dark all over – too high kV overexposed
48
Q

State when a grid would be used whilst imaging.

A

When an area of interest is over 10cm

49
Q

State the difference between computed radiography and direct radiography

A

Direct radiography uses a cassette that links straight to the Computer

Computed radiography uses a special cassette that needs to be placed in a reader for processing.

50
Q

Give 2 reasons for underdevelopment.

A

low temp

not developed for long enough

51
Q

Give 2 reasons for underdevelopment.

A

low temp

not developed for long enough

52
Q

What is the lead lining?

A
  • Inner case made of lead

- Surrounds tube head ensuring x-rays don’t escape as the lead case absorbs any radiation

53
Q

What is the glass envelope?

A

-A glass vacuum that contains the Anode and Cathode of the x-ray tube

54
Q

What is the vacuum?

A
  • Space where all air/gasses have been extracted
  • Allows the electrons/x-rays to travel in a straight line (if air/gasses present, electrons/x-rays would bounce off the particles and be misdirected)
55
Q

What do cooling fins do?

A

Disperse the heat

56
Q

What is the focusing cup?

A
  • Recess where the filament lies

- Directs the electrons towards the Anode

57
Q

What is the filament?

A
  • Part of the cathode
  • Made of tungsten
  • Part of a low-energy circuit in the Cathode
  • When heated it releases electrons from their orbit
58
Q

What is the anode?

A

The tungsten target

59
Q

What does the copper stem do?

A

Acts as a conductor of heat and draws the heat away from the tungsten target

60
Q

What does the oil do?

A

Transfers heat away from the Anode

61
Q

What is the aluminium filter?

A

Flat sheet of aluminium covering the window which absorbs any soft x-rays

62
Q

What is the cathode and what happens here?

A

Formed of a tungsten filament

Current passed through the filament causing it to heat up

Causes electrons from the filament particles to be released - thermionic emission

63
Q

What happens during electron transmission?

A

On activation of the exposure button a voltage (kV) is applied across the cathode and anode

Electrons are ‘fired’ across the vacuum from the cathode to the anode

64
Q

What is the anode and what happens here?

A

Formed of a tungsten target

Positively charged to attract electrons from the cathode

As electrons hit the target x rays are produced (1% x rays 99% heat energy)

65
Q

Why is the target angled?

A

Target is angled to ensure x rays are directed out of the tube head through the window

66
Q

By how many degrees is the target angled?

A

20 degrees

67
Q

What does the kV (voltage) affect?

A

The speed of the electrons travelling from the cathode, and therefore the energy of the x rays produced

68
Q

What does the mA (current) affect?

A

The number of electrons released, and therefore the number of x rays produced

69
Q

What does the exposure time affect?

A

The length of time of exposure affects how long the electrons are released for and therefore the number of x rays

70
Q

Is the cathode -ve or +ve?

A

Negative

71
Q

Is the anode -ve or +ve?

A

Positive

72
Q

What is the actual focal spot?

A

The area of the target which the electrons strike (the area in which heat is produced).

73
Q

What is the effective focal spot?

A

The angulation of the target means that the x-ray beam appears to originate from a much smaller area

74
Q

What is X-ray output limited by?

A

The amount of heat generated at the target

75
Q

In which machines would there be a stationary anode?

A

Low powered portable machines

76
Q

What machines would you find rotating anodes in?

A

Larger, more powerful machines

77
Q

What is the benefit of a rotating anode?

A

More efficient at removing heat

78
Q

What is the collimation device called and what does it do?

A

Light beam diaphragm

Controls size of x-ray beam

79
Q

How do you clean a casette?

A

Once a month (depending on caseload)

Clean from the inside out using circular motions

Use mild soapy water or a specially made cleaner

Leave upright to dry

Label casette with initials, date cleaned

Load new film in to casette.

80
Q

What is a developer?

A

A chemical solution that converts the latent image on a film to a visible image

Converts the exposed silver halide crystals to black metallic silver

The process is known as reduction and the developer acts as a reducing agent

81
Q

What step follows developing?

A

Rinsing

82
Q

Describe rinsing.

A

Stops the developing process

Rinses the developer from the film

Prevent carryover contamination to the fixer

83
Q

How long does the first rinse stage last for?

A

10 - 30 seconds

84
Q

Describe the rinsing stage.

A

Clears the unexposed silver halide crystals from the film

Hardens the gelatin coating so that it is less easy to damage

Should take twice the amount of time as developing

85
Q

Why must the unexposed silver halide crystals be removed during fixing?

A

If the unexposed silver crystals were to remain on the film they would discolour and darken with the exposure of light.

86
Q

What temperature may staining occur during fixing?

A

If the fixer is above 21 degrees Celcius

87
Q

Which 2 chemicals may be present in fixer solution that dissolves unexposed silver halide?

A

Sodium

Ammonium thiosulphate

88
Q

Describe the second rinsing stage

A

Films should be washed in circulating water so that both surfaces of the film receive freshwater continuously

In MANUAL processing the average suggested wash time is 20 -30 minutes with periodic agitation or water circulation

In AUTOMATIC processing the water system of the processor keeps a constant flow of temperate water through and around the wash rack and film

89
Q

Describe the drying stage.

A

The usual method is to clip the films to a taut line over a sink taking care that they do not touch each other.

The atmosphere should be dust - free with a good air circulation.

Drying frames and warm - air drying cabinets are also available and are useful if film throughput is high.

90
Q

What’s the difference between a non-screen film and a screen film with regards to processing?

A

Emulsion on non - screen film is thicker than that of screen film

It takes longer for the developing and fixing chemicals to penetrate the emulsion and act on the silver halide crystals

Development time should normally be increased by about one minute and clearing time in the fixer will be several minutes longer.

91
Q

List the differences between manual and automatic processors.

A

Automatic uses more water

Automatic is faster and only has 4 steps (rinse stage after developing stage is omitted)

Automatic runs at a higher temperature

92
Q

What’s the difference between computed and direct radiography?

A

Computed radiography needs a special casette which is then placed in a reader

The image in direct radiography is sent straight to the computer

93
Q

What’s the difference between computed and direct radiography?

A

Computed radiography needs a special casette which is then placed in a reader

The image in direct radiography is sent straight to the computer

Diagnostic Imaging Techniques (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions