Radiography Flashcards
(122 cards)
1
Q
Name the 5 imaging techniques
A
- Radiography
- CT scanning
- Ultrasound
- MRI scanning
- Scintigraphy
2
Q
Radiology is the ______ of radiographs
A
Radiology is the interpretation of radiographs
3
Q
Radiography is the ______ of radiographs
A
Radiography is the acquisition of radiographs
4
Q
What are the 4 radiographic processes?
A
- X-ray production
- X-ray/patient interaction
- X-ray detection
- Radiograph interpretation
5
Q
Do X-rays have a shorter or longer wavelength?
A
Short with a high frequency
6
Q
Muscles appear what colour in an X-ray?
A
Black
7
Q
What is the half value layer?
A
Thickness at 50% transmission
8
Q
Name 3 factors that affect the x-ray opacity
A
- Thickness of tissue
- Beam energy
- Chemical feature of tissue
9
Q
kVp have a large impact on exposure. True/False?
A
True
10
Q
Using contrast improves ______ interpretation
A
Using contrast improves tissue interpretation
11
Q
What is an ultrasound?
A
The use of high frequency sound waves to create an image
12
Q
Ultrasound uses electromagnetic radiation. True/False?
A
False
13
Q
Ultrasound particles transfer energy through a medium. Do particles move through the medium?
A
No
14
Q
Why is gel used on the skin when doing an ultrasound?
A
Air between the skin and transducer creates artifacts
15
Q
Ultrasound excels at soft tissue detection. True/False?
A
True
16
Q
Fluid is less dense than soft tissue in an ultrasound. True/False?
A
True
17
Q
What is an acoustic shaddow?
A
An area through which sound waves fail to spread due to an obstruction.
18
Q
What does CT stand for?
A
Computed tomography
19
Q
What does MRI stand for?
A
Magnetic resonance imaging
20
Q
What type of electromagnetic radiation does MRI use?
A
Non-ionising
21
Q
What are MRIs good for imaging?
A
Brain and spinal cord
22
Q
What are the 2 levels of CT?
A
Bone level
Window level
23
Q
MRI uses ____ to align _____ nuclei
A
MRI uses magnets to align hydrogen nuclei
24
Q
What is a comminuted fracture?
A
Break or splinter of the bone into fragments
25
What is subluxation?
Partial dislocation
26
Name 2 predisposing factors for arthritis?
Osteophytes
| Joint conformation
27
What are osteophytes?
Bony projections associated with cartilage degeneration at joints
28
Bone tumours are usually found in the proximal limb. True/False?
True
29
What are 4 things we assess with an organ?
Location
Size
Contour
Opacity
30
Which imaging modalities are dangerous to be exposed to?
CT
Radiography
Nuclear medicine
31
List the 5 properties of x-rays
1. Travel in straight lines in a wave
2. Penetrate body tissue
3. Make certain phosphors fluorescent
4. Photographic effect
5. Produce biological changes in the body tissue
32
What makes an x-ray photographic?
They produce a latent image on a flim
33
What makes objects in x-rays fluorescent?
Certain crystalline materials emit light after absorbing x-rays
34
How are X-rays produced?
In an x-ray tube when fast moving electrons are slowed down or stopped
35
What 3 things are required to produce an x-ray?
1. Source of electrons
2. Target to stop electrons
3. Method to accelerate them from source to the target
36
What are the 3 things inside the x-ray tube?
1. Cathode
2. Anode
3. Focal spot
37
What is the function of the cathode in an x-ray tube?
Provide a source of electrons and direct the electrons towards target
38
The amount of current applied to the filament is measured in _______
The amount of current applied to the filament is measured in milliamperes (mA).
39
What is the purpose of the anode in an x-ray tube?
Stop electrons
40
Name the 2 types of anodes in an x-ray tube
1. Stationary anode
| 2. Rotating anode
41
What are 3 advantages of a stationary anode in x-ray tube?
1. Smaller and mobile
2. Less expensive
3. Reliable
42
What are 3 disadvantages of stationary anodes in x-ray tubes?
1. Lower output
2. Longer exposure times
3. Movement blur
43
What are 2 advantages of a rotating anode in an x-ray tube?
1. high output
| 2. short exposure times
44
What are 3 disadvantages of a rotating anode in an x-ray tube?
1. more expensive
2. higher maintenance
3. specialised installation
45
What is the focal spot in an x-ray tube anode?
Target (part of the anode that is bombarded by electrons)
46
The _____ the focal spot the _____ the x-ray image
The smaller the focal spot the sharper the x-ray image
47
What is the line focus principle?
The way the anode surface is angled to allow for a larger area on the actual focus, and a smaller area on the effective focus.
48
What does kVp stand for?
Kilovoltage
49
What does kilovoltage refer to in the exposure factors of x-rays?
The high voltage used to accelerate electrons from cathode to anode
50
What does mA stand for?
Milliamperage
51
What does mA refer to in the exposure factors of x-rays?
Controls the intensity/density of the beam
52
Name 3 exposure factors of X-rays
1. Time
2. Milliamperage (mA)
3. Kilovoltage (kVp)
53
Bone absorbs less x-rays than soft tissues. True/false?
False
54
What is scatter radiation?
when the primary beam interacts with the object that it is passing through
55
Scatter radiation is undesirable. True/False?
True
56
What are 2 reasons why scatter radiation is undesirable?
1. Harmful to person in the vicinity during X-ray exposure
| 2. Degrades film quality
57
Scatter increases as ____ increases and with _____ exposure times.
Scatter increases as kVp increases and with longer exposure times
58
What are 2 ways to reduce scatter in an x-ray?
1. Use the appropriate kVp setting
| 2. Cone down the primary beam to the area of interest only
59
What are the 5 degrees of radiopacity?
Black (air), dark (fat), dark grey (water), grey (bone), white (metal)
60
What is DDR
Direct digital radiography
61
What is CR?
Computerised radiography
62
What is fluroscopy?
Uses an image intensifier of an x-ray detector to capture a radiographic image
63
What is fluoroscopy used for imaging?
GI tract
64
What does DICOM stand for?
Digital imaging and communications in medicine
65
What is DICOM?
Global standard for transmission of images
66
What does PACs stand for?
Picture archiving and communications system
67
Name the 3 factors that affect detail of the radiographic image
1. Focal spot size
2. Focus to film distance/source to image distance
3. Object to film distance
68
What is radiographic contrast?
The measurable distance between two adjacent densities
69
What is radiographic density?
The degree of blackening on a film
70
What is radiographic detail?
The definition of the edge of an anatomical structure on a radiograph
71
What is the Penumbra effect?
When a larger focal spot allows greater divergence of the x-ray beam which causes blurring of the edges of the image
72
Radiographic projections are named by describing where the x-ray beam enters the body and where it exits the body. True/False?
True
73
What does orthogonal views mean?
Taking two views at right angles to each other
74
When possible, where should the x-ray beam be directed to?
The floor
75
You must cone down to the area of interest only. True/False?
True
76
The central ray of the x-ray beam should be ______ to the cassette and _____ over the area of interest
The central ray of the x-ray beam should be perpendicular to the cassette and centred over the area of interest
77
What is the standard method to view radiographs (orientation of image)?
View lateral radiographs as if animal's head was to the left of the monitor with their spine at the top.
78
Image identification is a legal requirement. True/False?
True
79
Why is taking orthogonal views important?
Some pathologies cannot be visualised on one view
80
What are the effects of ionising radiation?
Chemical changes to DNA
81
What are the 4 ways that ionising radiation affect cells?
1. Cell death
2. Can pass through with no effect
3. Cell damaged and not repairable
4. Cell damaged and repair themselves
82
What tissue is the most sensitive to radiation?
Blood forming organs
| Reproductive organs
83
What tissues are the least sensitive to radiation?
Nervous system
| Muscles and connective tissue
84
What are the 4 things that influence the effects of radiation?
1. Sensitivity of tissue
2. Rate of delivery
3. Amount and characteristic of radiation involved
4. Amount of body exposed
85
Define acute impacts
effects due to exposure to high amounts of ionising radiation over a short period of time
86
Name examples of acute radiation injuries
Atomic bombs, nuclear reactor accidents
87
Define chronic injuries
Effects that take time to become evident
88
Name examples of chronic radiation injuries
Cancer, cataracts
89
Radiation doses are cumulative. T\F
True
90
Define somatic effects
effects on the physiological functioning of the body in the individual
91
Define genetic effects
Damage to the cells in the reproductive system. Mutation of genes. Affects future generations.
92
Examples of somatic effects
Radiation sickness, Radiation burns, Inflammation, Cancers, Skin reddening
93
Examples of genetic effects
Mutation of genes, Inherited abnormalities
94
Define stochastic effects
Effects that occur on a random basis with the effect being independent to size of the dose. No threshold
95
Define non-stochastic effects
Related directly to dose received. Effect is more severe with a higher dose. Has a threshold below which the effect will not occur
96
Example of stochastic effects
Cancer
97
Examples of non-stochastic effects
Skin burn
98
What is the millisievert?
A measure of absorption of radiation by the human body.
99
What is the mSv used to measure?
1. Absorbed dose to all organs of the body
2. Relative harm level of the radiation
3. Sensitivities of each organ to radiation
100
How much radiation is safe?
No amount is safe
101
What does ALARA stand for?
As Low as Reasonably Achievable
102
What is the maximum permissible dose for exposed persons in vet med?
20mSv per year
103
What is the maximum permissible dose for members of the public?
1mSv per year
104
What are the 3 radiation protection principles?
1. Justification
2. Optimisation
3. Dose limits
105
Justification is a radiation protection principle that highlights what?
The benefits should outweigh the costs/dangers
106
What does optimisation involve?
Equipment and methods should be selected to ensure the radiation doses received by the exposed person and members of the public are kept low as possible
107
What are the 3 roles associated with radiation regulation?
1. Responsible person
2. Vet
3. Operator
108
What is the vet responsible for?
Justification and requesting radiographic procedures
109
What is the operator responsible for?
Taking the x-rays requested by vet and follows correct protocol.
110
What does the responsible person do?
Overall management of radiation safety in the practice. Legal responsibility.
111
What is outlined in the radiation management plan?
Safety policies, Monitoring, Standard work procedures, Record keeping, Training of staff, Roles and responsibilities, Maintenance
112
When is the developing embryo most sensitive to radiation?
First trimester
113
What 2 things should pregnant staff comply by?
Do not hold patients, Use dosimeter
114
What is scatter radiation?
Secondary radiation. Produced when primary beam interacts with the patient/table/detector
115
What are the 3 safety principles of ALARA?
1. time
2. distance
3. shielding
116
Name 4 things that can be implemented to reduce time of exposure
1. Use sedation
2. Minimise retakes
3. Rotate staff
4. Remove extra people from room
117
Name 4 things that can be implemented to control the distance from exposure
1. Stand as far away as possible
2. Use cassette holders
3. Cone down primary beam
4. Don't hand-hold portable units unless absolutely necessary
118
What type of shielding can be used?
Lead-equivalent
119
Name 3 things to consider when using shielding
1. PPE only blocks scatter radiation not the primary beam
2. Never have any body part in the primary beam even with PPE
3. It is poor practice to see a lead glove on a radiograph
120
Is there a safe threshold for radiation?
No
121
What do dosimeters do?
Measure radiation exposure
122
Sedation is critical to radiation safety. True/False?
True
