RESIT: Radiology Flashcards

1
Q

How would you describe an x-ray?

A

Identical to gamma rays - with lower energy values.
No charge, weight or mass.
Very fast.
Cause ionisation.

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

Visible light range

A

400-700nm

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

What view is this?

A

Intra-oral occlusal (maxilla)

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

What view is this?

A

Intra-oral occlusal (mandible)

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

What view is this?

A

Extra-oral: lateral cephalogram

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What view is this?

A

Extra-oral: postero-anterior mandible

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

What view is this?

A

Extra-oral: lateral oblique mandible

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

What view is this?

A

Occipital-mental view of facial bones

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

Jack is under doing orthodontic treatment, they need to visualise the relationship of the teeth to the jaws and the mandible to the rest of the facial skeleton.

A

Lateral cephalogram

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Olivia has fractured her mandible playing rugby.

A

Postero-anterior mandible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Olivia has fractured her mandible playing rugby.

A

Postero-anterior mandible

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

Tommy (a child) cannot tolerate a bitewing and keeps crying.

A

Lateral oblique mandible

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

Ron is in a dental surgery that doesn’t have a DPT, he broke his mandible falling over on a night out.

A

Lateral oblique mandible

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

Susie is in A&E with facial trauma after tripping on her heels dancing on a table.

A

Occipital-mental views of facial bones

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

Adam has fought the bouncer at aura and is suspected to have damage his orbits, maxilla and zygomatic arches.

A

Occipital-mental view of facial bones

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

Which radiograph may require multiple takes?

A

OM views are taken twice from two angles: first at 10 degrees, second at 30 degrees.

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

Adam had to stand for his OM view radiograph, why?

A

Taking the films erect can help demonstrate the fluid levels the antra.

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

What is the standard intra-oral technique with the receptor parallel to the tooth called?

A

Paralleling technique

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

When would you take an intra-oral radiograph without a holder from an angle, and what is this called?

A

When the patient can’t tolerate a holder in their mouth or during endodontic procedures. Bisected angle technique

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

What colour holder would you select for anterior teeth?

A

Blue

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

What colour holder would you select for posterior teeth?

A

Yellow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What colour holder would you select for bitewing?

A

Red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What makes to tooth appear elongated?

A

Vertical angulation downwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What can make the tooth appear shorter?

A

Vertical angulation upwards

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

What is the prime positioning when taking an x-ray?

A

Short object to film distance, and a long source to object distance.

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

Is this a bad x-ray?

A

Yes, vertical angulation of the beam has foreshortened the teeth and separated the cusps.

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

Is this a bad x-ray?

A

Yes, horizontal overlap of the teeth caused by horizontal angulation of either the receptor or the beam.

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

Is this a bad x-ray?

A

Yes, vertical angulation and cone-cutting (collimator has cut off the image).

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

Is this a bad x-ray?

A

Bottom right: vertical angulation is wrong giving foreshortened teeth.

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

Film size: anterior periapical

A

0 (only use a 1 if unique anatomy/long canine)

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

Film size: posterior periapical

A

2 (typically won’t do posteriors on young children as periapical pathology is uncommon)

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

Film size: bitewing (8-10 years old)

A

0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Film size: bitewing (<10 years)

A

Just <10 maybe = size 1

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

Film size: bitewing (adult)

A

Adult = size 2

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

What is able to be altered by the control panel?

A

the time of the exposure
the area of the exposure
the type of film we are taking (e.g bitewing etc)

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

white

A

cathode (-ve)

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

black

A

anode (+ve)

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

brown

A

aluminum filter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

pink

A

X-rays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

blue

A

lead collimator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

purple

A

Copper stem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

orange

A

glass housing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

yellow

A

tungsten target

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

green

A

tungsten wire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

red

A

molybdenum (focussing cup)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Basics of how dental x-ray works

A

Current gets passed along tungsten wire, electrons are excited and wire gets hot.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Basics of how dental x-ray works

A

Current gets passed along tungsten wire, electrons are excited and wire gets hot.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Continuous spectrum

A

Bremsstrahlung/breaking radiation.

Electrons fired across from the wire with heat the tungsten target, some of the electrons will penetrate the atoms of the target material being attracted to the nucleus of the atom.

This caused slowing down or deflection of electrons from the atom’s electron shell. There’s a wide range of x-ray wavelengths produced.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Continuous spectrum (or bremsstrahlung/breaking radiation)

A
  1. Electron from cathode comes in and decelerated as a result of pull from the nucleus.
  2. The kinetic energy of that electron is transferred to x-ray photon energy.

Hence there is no specific energy produced its continuous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Line spectrum

A
  1. Electron from cathode comes in and knocks out an electron from L or K shell (innermost).
  2. The shells balance themselves by an electron dropping down to replace the knocked-out one.
  3. This movement to a “lower” energy level means the electron loses energy.
  4. This energy is in the form of an x-ray photon.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Photon energy is directly related to

A

kV across the X-ray tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

The higher the kV…

A

the more capable it will be to penetrate through material (dark image).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Kv needed for characteristic x-ray to be produced

A

69.5kV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Large wavelength, low energy

A

Radiowaves/microwaves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Medium-shortish wavelength, medium-lowish energy

A

Infrared

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Medium-longish wavelength, medium-highish energy

A

ultraviolet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Wavelength and energy: X-ray compared to gamma rays?

A

X-rays: lower energy, longer wavelength

Gamma ray: higher energy, shorter wavelength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

At what point does the electromagnetic spectrum become ionising?

A

moving from ultraviolet radiation to x-ray and gamma rays.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Attenuation

A

reduction in intensity of beam due to scattering & absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What type of energy photons are absorbed by soft tissues?

A

Low energy photons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Film type: intra-oral radiograph

A

Direct film: x-rays act directly on silver halide crystals on the film.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Film type: extra-oral radiograph

A

Indirect film: x-rays ‘hit’ intensifying screens producing light photons which then acts on silver halide crystals on the film.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

PSP vs solid state

A

PSP more commonly used in DDH.

Solid state shows better image but requires specific holder and is less well tolerated by patients. Has the black wire coming from it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

How do PSP work?

A
  1. X-ray hits the plate: stable exited state.
  2. Plate is scanned by red laser: unstable excited state.
  3. Blue light is emitted and this is collected by a scanner (vista) which converts it’s to an image.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Solid state sensor

A

A: back cover
B: Silicon wafer (converts light to electrical signal)
C: Scintillator layer (converts x-ray to light)
D: front cover

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Solid state sensor: how does CCD work?

A

X-rays hit scintillator layer, producing light which reacts with the silicon wafer.

Electrons released produce charge which is converted to the image.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Solid state sensor: CCD vs CMOS system

A

CCD is better but more expensive, more commonly used.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Where are images stored from DDH?

A

PACS (picture archiving communication system) - Livingstone.

T113H - unique accession number for images taken at DDH.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Deterministic effects of radiation

A

Non-stochastic - those we know will occur, threshold dose (known), somatic effects (this is utilised in radiotherapy for cancer patients)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Non-deterministic effects of radiation

A

Stochastic - those which may occur, down to chance, no threshold known.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Dose of radiation that is harmful

A

2-10 Sv

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Does of radiation that can cause death in 24 hours

A

> 10 Sv

73
Q

What kind of radiation causes genetic effects (i.e could be passed onto future children)?

A

non-deterministic

74
Q

Dental workers radiation dose

A

<0.1mSv (never exceed 1)

75
Q

What speed film has lowest radiation (D speed or F speed)?

A

F speed is best (fastest).

76
Q

The younger the patient, the _____ the risk of radiation.

A

The worst

77
Q

What collimator is best for reducing dose: rectangular vs round?

A

Rectangular

78
Q

Controlled area size

A

1.5 metres (always 2 metres at DDH)

79
Q

What is wrong with this radiograph?

A

Light damage. Large black area shows the over exposed area from light seeping in.

80
Q

What is wrong with this radiograph?

A

Light damage. Fogging is visible as well as over-exposed black area.

81
Q

What is wrong with this radiograph?

A

Film is back to front. Lead foil pattern visible on the left hand side.

82
Q

Film

A

B: Super coat
C: Emulsion
A: Adhesive layer
D: Base

S, E, A, B - super coats emulate afgan blankets.

83
Q

Emulsion layer in film

A

Silver halide crystals suspended in gelatin.

84
Q

Image formation on dental film

A

Silver halide crystals are sensitised by x-ray photons, reducing them to black metallic silver.

85
Q

Larger silver halide crystals…

A

Produce film faster but at lower quality.

86
Q

Indirect film is sensitive to _________ rather than __________

A

Indirect film is sensitive to light rather than x-rays.

87
Q

Intensifying screens pros and cons

A

Less radiation, less detail on radiograph

88
Q

What’s wrong with this radiograph?

A

It’s been bent.

89
Q

5 stages of image developing

A
  1. Develop
  2. Wash
  3. Fix
  4. Wash
  5. Dry
90
Q

Components of an automatic processor

A

A - Feed in rollers
B - Developer rack
C - Fixer rack
D - Wash rack
E - Dryer

91
Q

Developing the image allows you to see the latent image with the naked eye…

A

as the developing agents phendone and hydroquinone act upon sensitised silver halide crystals to reduce to black metallic silver.

92
Q

How does fixing allow the unexposed silver halide crystals to be removed?

A

The fixing agents change the unexposed silver halide crystals to a soluble compound that can be washed away.

93
Q

What causes this green brown tinge?

A

under fixing

94
Q

Legislation meaning employers had a legal duty to ensure their staff were safe and risk free at work.

A

Health and safety at Work act 1974

95
Q

How would you position your bite block for a bitewing radiograph?

A

Place the block on the centre of the 6th molar.

96
Q

Comment

A

Just OK

97
Q

Comment

A

Repeat, no upper bone levels visible posterior to the 7.

98
Q

Comment

A

Repeat, because 8 collimate off.

99
Q

Comment

A

Repeat, receptor size too small.

100
Q

Comment

A

Repeat, vertical angulation causing elongation and lower bone level projected off.

101
Q

Comment

A

Perfect

102
Q

Comment

A

Repeat, cone-cutting (collimation is cover lower bone levels).

103
Q

Comment

A

Good

104
Q

Comment

A

Repeat, number 4 and receptor squint.

105
Q

Comment

A

Good

106
Q

Comment

A

Repeat, corner of film bent over so large area not exposed.

107
Q

Comment

A

Repeat, too much overlap

108
Q

Comment

A

Repeat, patient not biting on block

109
Q

IR (ME) R

A

The ionising radiation (medical exposure) regulation 2017 to protect the patient.

110
Q

IRR

A

The ionising radiation regulation 2017 protect both staff and public but also deal with patient protection in relation to the equipment we use.

111
Q

The employer

A

the boss, must ensure that their establishment is complying with IRMER.

112
Q

The practioner

A

The person who justifies the exposure. They must be aware of and adhere to the correct referral criteria for dental exposures. The practitioner assumes legal responsibility for the exposure when they put their name to it.

113
Q

The operator

A

Anyone who is involved in the production of a radiograph. That includes the person who asks the patient to simply sit in the chair, to the nurse who develops the film.

114
Q

The referrer

A

The person who has clinically examined the patient and referred them for the radiographs and who is responsible for viewing that radiograph and recording the findings in the patient’s notes

115
Q

The dentist

A

Dentists are quite unique in the fact that they can be every single one of these roles, therefore need to pay close attention to this document.

116
Q

Two main IRMER regulations

A
  1. Quality assurance programmes for standard operating procedures.
  2. Practioner and operators have undertaken CPD.
117
Q

Training

A

5 hours of CPD every 5 years

118
Q

Basic SOPs

A

How we justify the exposure
How we correctly identify the patient
How we collect the equipment
How we expose the patient
How we clean the phosphor plates and develop them.

119
Q

So what exactly do we look at in QA programme?

A

Image quality
X-ray equipment
Image processing (film and digital)
Working procedures
Training
Audit

120
Q

X-ray equipment requirements

A

Inventory must be kept.
Regular testing (every 3 yrs or so)
- this includes checking representative patient doses.
*at DDH we QA test our equipment every 3 months.

121
Q

What happens to the equipment annually?

A

Annual service by a suitably qualified engineer (company called MI Healthcare).

122
Q

What is the main method of checking performance known as?

A

Sensitometry

123
Q

What does sensitometry involve?

A

A daily check of the developer, the idea is to compare a film developed with fresh chemistry with a new film taken every day to check image quality has not deteriorated as the developer becomes exhausted.

124
Q

What image can you expect to see if the developer has become exhausted?

A

Will give you a pale image.

125
Q

What causing film fogging?

A

Exposure to light

126
Q

How often should you perform a visual check on solid state sensors and PSP plates?

A

Weekly: for any signs of damage, and x-ray the sensor once a month and study the resultant image.

127
Q
A

Bent

128
Q
A

Thumb print

129
Q
A

Scratch/crack

130
Q
A

Bite

131
Q

Who can take radiographs?

A

A state registered dentist or hygienist

dental nurses with a post-qualification certificate in dental radiography or radiographers. Must also be able to provide evidence that they are competent to use the equipment in the practice.

132
Q

What is cervical burnout?

A

Overexposure of the film can “burnout” the thinner sections of enamel, giving the false appearance of cervical caries.

133
Q

Radiographing caries in children: risk

A

High - 6 months
Moderate - 12 months
low - 12-18 months (deciduous), 24 months (permanent)

134
Q

Radiographic baseline

A

Outer canthus of the eye to the external auditory meatus, and this represents the base of the skull (red)

135
Q

Frankfort plane

A

The inferior orbital margin to the upper border of the EAM. (green)

136
Q

Maxillary occlusal plane

A

the ala of the nose to the tragus of the ear (yellow)

137
Q

Landmark for a CT scan?

A

Maxillary occlusal plane

138
Q

Landmark for extra-oral radiography?

A

Radiographic baseline

139
Q

Landmark for DPT?

A

Frankfort plane

140
Q

Positioning for anteroposterior

A
141
Q

Positioning for postero-anterior

A
142
Q

Positioning for a lateral cephalgram

A
143
Q

Connie is suspected to have a cyst or malignancy on her jaw due to the media-lateral expansion.

A

PA mandible

144
Q

Ryan thinks he broke the posterior body of the mandible and ramus in his rugby match.

A

PA mandible

145
Q

When requesting a PA, you would usually…

A

request in conjunction with a DPT.

146
Q
A

Positioning for lateral oblique mandible

147
Q

Rob has a potential mandibular fracture on the ramus.

A

Lateral oblique mandible using a skull unit or conventional x-ray unit.

148
Q

Kiki has infected molars.

A

Lateral oblique mandible using a dental tube with either horizontal or vertical angulation.

149
Q
A

lateral oblique mandible using horizontal angulation

150
Q
A

lateral oblique using vertical angulation

151
Q

Rachel is about to undergo orthognathic surgery.

A

Cephalometric radiograph

152
Q

Daniel is about to get invasive orthodontic treatment.

A

Cephalometric radiograph

153
Q

Rohan broke his orbits and wall of maxillary sinus and potentially the body of the zygoma in a bar fight

A

OM10

154
Q

Positioning for Occipital mental views

A

OM10 or OM30

155
Q

Medical physicist or specialist company. Consult this person planning new surgery etc. radiation over dose. Establishing the controlled area. Their name and details can be found in the Radiation Protection File.

A

RPA: Radiation protection adviser

156
Q

How do the RPA and the Medical Physics Expert differ?

A

They could be the same person.

RPA - IRR2017
MPE - IRMER2017

157
Q

This person is usually a dentist or senior member of staff. Ensures compliance with IRR 2017 and local rules. Closely involved in radiography. Has authority to carry out their duties.

A

RPS: Radiation Protection Supervisor.

158
Q

Highest radiation dose to lowest (of various scans)

A
  1. CT mandible and maxilla
  2. Craniofacial CBCT
  3. Dento-alveolar CBCT
  4. PA skull
  5. Lateral skull
  6. Chest PA
  7. Maxillary occlusal
  8. Lateral cephalometric
  9. DPT
  10. Bitewing/periapical
159
Q

mA

A

Amperage = tube current.

160
Q

Increasing amperage (mA)

A

Higher production of electrons inside the X-ray tube, increase radiation = higher exposure/darkening of film.

161
Q
A

Green - soft palate
Yellow - hard palate
Red - anterior nasal spine

162
Q
A

orangey-yellow - maxillary sinus (medial wall)
green - maxillary sinus (floor)
blue - maxillary sinus (posterior wall)
yellow - zygomatic arch
purple - zygomatic buttress
pink - pterygoid plates

163
Q

Comment

A

Faulty; incorrect selection of exposure factors – not enough radiation equals an underexposed image.
Film didn’t spend enough time in the developer tank
Developer is exhausted or at too low a temperature.
Incorrect dilution of chemicals

164
Q

Comment

A

incorrect exposure factor

165
Q

Comment

A

Tube isn’t sitting right with all 4 corners.
Film is damaged with several scratched and marks and its under exposed.

166
Q

Comment

A

Insufficient washing, residual chemicals.

167
Q

Comment

A

Static electricity discharging on the film. Caused when film is pulled too quickly from packet in a dry atmosphere.

168
Q

Comment

A

Chin too far down, patient is also rotated.

169
Q

Comment

A

Narrow incisors = patient too far into the machine

170
Q

Comment

A

Wide incisors = patient too far out of the machine

171
Q

Simon has intracranial bleeding from being hit on the head by a bat.

A

CT scan

172
Q

Increase of mA or S

A

S – seconds; increasing the time of exposure enhances the ‘sharpness’ or definition of x-ray this is typically reported on alongside mA.
mAs – milliampere-seconds; current going through the x-ray tube, should take into account radiographic density (i.e. higher mAs for a abdomen scan versus for a hand scan as there are less structures so its less necessary for contrast between the different structures).

mA (current) x S (time) = mAs —> changes in this will effect contrast and an increase in mAs will increase radiation dose.

173
Q

Increasing kV

A

increases the exposure given to the film, potentially darker image (may need a greater exposure depending on what is being x-rayed if there are more structures = increase the Kv).

174
Q

The dentist is trying to locate sam unerupted maxillary canine

A

CBCT

175
Q

Susan has a cleft palate

A

CBCT

176
Q

Roxy needs to an assessment of her resorpted unerupted molar

A

CBCT

177
Q

Lewis has disc issues with his TMJ and potentially a salivary gland problem.

A

MRI

178
Q

Rodrick has a neck swelling that is suspicious

A

Ultrasound

179
Q

Inverse square law

A