50 Q Flashcards

1
Q

In an intra-oral X-ray set, X-ray photons are produced at the…

  1. aluminium filter
  2. cathode
  3. filament
  4. focussing cup
  5. tungsten target
A
  1. tungsten target
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2
Q

In an intra-oral X-ray set, what is the purpose of the aluminium filter?

  1. Absorb scattered radiation
  2. Help create a sharper image
  3. Preferentially attenuate low energy X-rays
  4. Prevent backscatter from fogging the image
    5 . Protect the operator
A
  1. Preferentially attenuate low energy X-rays
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3
Q

In an intra-oral X-ray set, what is the purpose of the collimator?

  1. Absorb scattered radiation
  2. Focus the X-rays
  3. Protect the operator from scatter
  4. Remove the lower energy radiation from the beam
  5. Restrict X-ray beam to chosen area
A
  1. Restrict X-ray beam to chosen area
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4
Q

In an intra-oral X-ray set, the High Tension (Voltage) circuit…

  1. is in the 65-70 kVp range
  2. is usually about 6.5 - 7.5 mA
  3. is usually around 65,000 kV
  4. operates at around 50,000 Volts
  5. varies according to the exposure setting
A
  1. is in the 65-70 kVp range
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5
Q

Compton (inelastic) scatter…

  1. improves image quality
  2. occurs at discrete energy levels
  3. occurs when an electron interacts with an atomic nucleus
  4. produces an X-ray of energy equal to the binding energy of the k-shell
  5. reduces contrast in an image
A
  1. reduces contrast in an image
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6
Q

The mA current setting on an intra-oral X-ray set…

  1. controls the high tension (HT) circuit for the set
  2. controls the number of electrons produced at the filament
  3. is set higher for a bite-wing than for a periapical radiograph of an upper
    molar
  4. is the Mega Amp current
  5. is usually set for each exposure by means of the control box
A
  1. controls the number of electrons produced at the filament
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7
Q

In an intra-oral X-ray set, excess heat is …

  1. caused because X-ray
  2. production is inefficient
  3. conducted away by the copper block
  4. dissipated by convection in the oil surrounding the tube
    radiated away from the outer case
  5. All of the above
A
  1. All of the above
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8
Q

Rectangular collimation…

  1. ensures object and receptor are in the correct relationship
  2. helps align the tube to the film
  3. holds the film in the correct position
  4. is mandatory
  5. reduces the patient - dose by around 40%
A
  1. reduces the patient - dose by around 40%
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9
Q

The stochastic effects of ionising radiation…

  1. can result in radiation-induced erythema or burns
  2. cause no biological damage at low doses
  3. follow a linear-quadratic relationship
  4. have a safe threshold
  5. occur as the result of chance events
A
  1. occur as the result of chance events
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10
Q

. Which statement is true with regards to the paralleling intraoral technique?

  1. It enables the beam to be centred to the film
  2. It increases magnification of the image
  3. It is not appropriate for patients with disabilities
  4. It is not the technique of choice routinely
  5. Periodontal bone levels are poorly represented
A
  1. It enables the beam to be centred to the film
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11
Q

Collimation of the X-ray beam…

  1. is not necessary
  2. increases scattered radiation
  3. increases the volume of exposed tissue
  4. should be circular
  5. should be rectangular
A
  1. should be rectangular
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12
Q

The deterministic or non-stochastic effects of ionising radiation…

  1. are concerned with the risks of inducing cancer at low doses
  2. are dose-dependent
  3. are independent of the amount of radiation received
  4. have no threshold
  5. occur according to the laws of chance
A
  1. are dose-dependent
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13
Q

The X-ray beam should be…

  1. as close to the patient as possible
  2. kept on for as long as possible
  3. perpendicular to the tooth and image receptor to prevent distortion
  4. positioned perpendicular to the floor
  5. produced from a large focal spot
A
  1. perpendicular to the tooth and image receptor to prevent distortion
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14
Q

The risk of developing cancer from low doses of ionising radiation…

  1. clearly demonstrates a hormesis effect
  2. follows the linear-no-threshold model
  3. has a ‘dose threshold’
  4. is independent of the dose received
  5. is non-existent at very low doses
A
  1. follows the linear-no-threshold model
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15
Q

The Frankfort baseline is…

  1. a radiographic plane that bisects the first upper molar
  2. a radiographic plane that divides the face symmetrically from the crown
    of the head to the tip of the mandible
  3. a radiographic plane that extends from the external auditory meatus to
    the infra-orbital margin
  4. a radiographic term that describes normal anatomical appearances
    viewed on an DPT
  5. the relative position of the tube, cassette and patient during DPT
    examinations
A
  1. a radiographic plane that extends from the external auditory meatus to
    the infra-orbital margin
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16
Q

The National Diagnostic Reference Dose for intra-oral radiology is
approximately 2.0mGy.
What is this is expressed in terms of?

  1. Absorbed dose
  2. Committed dose
  3. Dose-width product
  4. Effective dose
  5. Equivalent dose
A
  1. Absorbed dose
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17
Q

An X-ray of a female patient of child-bearing age…

  1. can only be undertaken if she is given a lead apron to wear over her abdomen
  2. can only be undertaken within 10 days of the last menstrual period
  3. is prohibited under the Ionising Radiations(Medical Exposure ) Regulations unless a check is made if she is pregnant
  4. must be undertaken in accordance with local written procedures
  5. must not be undertaken if she is pregnant
A
  1. must be undertaken in accordance with local written procedures
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18
Q

Under IRMER Optimisation ensure that the…

  1. dose is as low as achievable and image quality is acceptable
  2. image quality is high
  3. patient dose is less than the Diagnostic Reference Level
  4. patient dose is low
  5. patient receives a dose at the diagnostic reference leve
A
  1. dose is as low as achievable and image quality is acceptable
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19
Q

Under IRMER…

  1. operators do not require theoretical training
  2. students under supervision must be trained before carrying out exposures
  3. the Operator must have practical training
  4. the Practitioner does not require theoretical training
  5. the Referrer must be appropriately trained
A
  1. the Operator must have practical training
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20
Q

Regarding Justification…

  1. Does not apply to asymptomatic exposures
  2. Examinations on children under 5 are not justified
  3. Examinations on pregnant patients are not justified
  4. Justification is not required for routine x-rays
  5. Justification must be carried out for every exposure
A
  1. Justification must be carried out for every exposure
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21
Q

Regarding Justification the…

  1. exposure is approved by the Practitioner and justified by the Operator
  2. exposure is justified by the Referrer and authorised by the Practitioner
  3. Operator is responsible for justifying the exposure
  4. Practitioner is responsible for justifying the exposure
  5. Referrer is responsible for justifying the exposure
A
  1. Practitioner is responsible for justifying the exposure
22
Q

The Ionising Radiation (Medical Exposure) Regulations 2017…

  1. are an Approved Code of Practice
  2. are intended to protect patients
  3. place a limit on the number of x-rays a patient can receive
  4. protect members of the Dental Team
  5. protect members of the public
A
  1. are intended to protect patients
23
Q

What do the Ionising Radiations Regulations 2017 require?

  1. All exposures to be restricted as far as reasonably practicable
  2. All exposures to patient to be within diagnostic reference levels
  3. All staff to be monitored for radiation exposure
  4. Doses to patients to be recorded
  5. Exposures of patients to be within Dose Limits
A
  1. All exposures to be restricted as far as reasonably practicable
24
Q

Members of staff should…

  1. inform her employer in writing if they believe they are pregnant
  2. not work with X-ray equipment
  3. tell their colleagues if they are more than six months pregnant
  4. tell their employer if they are in the first trimester of pregnancy
  5. wear a lead protective apron
A
  1. inform her employer in writing if they believe they are pregnant
25
Q

Concerning Controlled Areas…

  1. Access is permitted for employees only
  2. Are monitored by the Radiation Protection Adviser
  3. Are subject to written arrangements to control access
  4. Non-classified workers are not permitted to enter Controlled Areas
  5. Pregnant patients are not permitted to enter Controlled Areas
A
  1. Are subject to written arrangements to control access
26
Q

The Radiation Protection Supervisor (RPS)…

  1. is usually either the Practice Administrator or Senior Dental Nurse
  2. isn’t usually required in a hospital/dental school
  3. must be a dentist
  4. must be identified in the practice information leaflet
  5. must have received appropriate training
A
  1. must have received appropriate training
27
Q

The role of the Radiation Protection Supervisor is to…

  1. ensure Radiation Badges are changed monthly
  2. ensure that Local Rules are being followed and enforced
  3. ensure the Register of Training is kept updated
  4. ensure X-ray equipment has been regularly serviced
  5. write Local Rules for the Practice
A
  1. ensure that Local Rules are being followed and enforced
28
Q

The absorbed dose at the cone for a mandibular molar radiograph is
approximately…

  1. 0.1 Sv
  2. 2 mGy
  3. 3.2 mSv
  4. 10 cGy
  5. 25 mGy
A
  1. 2 mGy
29
Q

Bremsstrahlung or ‘braking radiation’ is…

  1. emitted at a particular (discrete) wavelength
  2. only produced at tube voltages above 50 kV
  3. produced when an X-ray photon strikes a Calcium atom
  4. the major source of photons in X-ray
  5. the primary cause of image noise
A
  1. the major source of photons in X-ray
30
Q

The useful interaction of photons with matter when taking intra-oral xrays is…

  1. characteristic radiation
  2. compton or inelastic scatter
  3. elastic recoil
  4. pair production
  5. photo-electric absorption
A
  1. photo-electric absorption
31
Q

What is a Diagnostic Reference Level (DRL)?

  1. It applies to any patient having an X-ray
  2. It defines the risk to the patient
  3. Is the radiation dose which should not be normally exceeded for a standard exposure
  4. The optimum dose from a procedure
  5. The prescribed radiation dose to the patient
A
  1. Is the radiation dose which should not be normally exceeded for a standard exposure
32
Q

Beam collimators should provide a minimum focus to skin distance
(FSD) of…

  1. 50mm
  2. 100mm
  3. 150mm
  4. 200mm
  5. 250mm
A
  1. 200mm
33
Q

Intra-oral radiography equipment should operate within which tube
potential range?

  1. 50 - 60 kV
  2. 60 - 70 kV
  3. 70 - 80 kV
  4. 80 - 90 kV
  5. 90 - 100 kV
A
  1. 60 - 70 kV
34
Q

X-ray production in a diagnostic X-ray tube is approximately how
efficient?

  1. 1%
  2. 5%
  3. 52%
  4. 95%
  5. 99%
A
  1. 1%
35
Q

How far away from the dental X-ray tube does the controlled area
extend?

  1. 1.5 metres
  2. 2 metres
  3. 2.5 metres
  4. As defined in the Local Rules
  5. At the extent of the exposure cable
A
  1. As defined in the Local Rules
36
Q

Regarding the Photoelectric effect…

  1. May result in scattered radiation
  2. The effect is independent of atomic number
  3. The incident photon interacts with a free electron
  4. The incident photon is completely absorbed
  5. The probability of photoelectric absorption does not depend on photon
    energy
A
  1. The incident photon is completely absorbed
37
Q

Regarding effective dose, it…

  1. expresses a cancer mortality risk to an individual
  2. expresses the probability of cancer incidence in a population
  3. expresses the radiation dose from an individual exposure
  4. is a measure of the chance a patient will die from cancer
  5. should be calculated for each examination undertaken
A
  1. expresses the probability of cancer incidence in a population
38
Q

Regarding absorbed dose…

  1. Absorbed dose is a measure of the energy deposited in tissue per unit mass
  2. Absorbed dose is a measure of the risk of exposure to ionising
    radiation
  3. Absorbed dose is defined only at the surface of the tissue we are interested in
  4. For the same amount of X-rays falling on tissue, the absorbed dose will
    be the same irrespective of tissue type
  5. The correct unit for absorbed dose is the Sievert
A
  1. Absorbed dose is a measure of the energy deposited in tissue per unit mass
39
Q
  1. Regarding the Bremsstrahlung (braking radiation) process…
  2. An incident electron interacts with the nucleus releasing an x-ray photon
  3. It describes how electrons move within atomic shells
  4. It is dependent on the binding energy of the atomic electrons
  5. It results in the ejection of an atomic electron
  6. The incident electron collides with a K-shell atomic electron
A
  1. An incident electron interacts with the nucleus releasing an x-ray photon
40
Q

Image unsharpness is not affected by…

  1. focal spot size
  2. geometric magnification
  3. grain size in film emulsion
  4. increase in kVp
  5. patient movement
A
  1. increase in kVp
41
Q

Patient dose is not affected by…

  1. decreasing exposure time
  2. increasing the Focus to Skin Distance
  3. increasing the tube filtration
  4. increasing tube potential (kVp)
  5. using a rotating anode target
A
  1. using a rotating anode target
42
Q

Dose optimisation is the process by which…

  1. a diagnostically relevant image is obtained at the lowest dose
  2. equipment is maintained
  3. maintenance engineers assess the quality of the equipment
  4. the best possible image quality is ensured
  5. the smallest dose to the patient is ensured
A
  1. a diagnostically relevant image is obtained at the lowest dose
43
Q

The minimum legal filtration for a dental X-ray set (up to 70kVp) is…

  1. 2.5mm Al
  2. 1.5mm Al
  3. 0.1mm Pb
  4. 2.0mm Cu
  5. 1.0mm Pb
A
  1. 1.5mm Al
44
Q

Deterministic effects of ionising radiation…

  1. are a necessary side effect of ionising radiation in dental practice
  2. are normally seen in routine dental exposures
  3. cannot be predicted before the exposure has happened
  4. have a threshold dose below which they do not occur
  5. include hereditary effects in future generations
A
  1. have a threshold dose below which they do not occur
45
Q

Stochastic radiation effects…

  1. are assumed to follow a linear no threshold relationship to dose
  2. are not present in dental radiography
  3. can be seen in patients a few weeks after exposure
  4. from a DPT are likely to be similar in magnitude to those resulting from
    average annual background radiation.
  5. have a threshold
A
  1. are assumed to follow a linear no threshold relationship to dose
46
Q

Compton or inelastic scattering…

  1. discriminates between hard and soft tissues
  2. helps build image contrast
  3. improves the quality of the captured image
  4. is the most likely source of radiation exposure to an operator
  5. predominates at low X-ray energies
A
  1. is the most likely source of radiation exposure to an operator
47
Q

The X-ray beam should be collimated to…

  1. ensure X-rays reach the target
  2. limit extraneous radiation that does not play a part in the imaging process.
  3. maximise Compton over photoelectric interactions
  4. minimise the photoelectric effect in tissue
  5. stop film fogging
A
  1. limit extraneous radiation that does not play a part in the imaging process.
48
Q

Equivalent dose is the…

  1. absorbed dose to an organ or tissue weighted for age and sex
  2. absorbed dose to an organ or tissue weighted for type of radiation
  3. absorbed dose to an organ or tissue weighted for type of radiation and
    tissue
  4. absorbed dose to an organ or tissue weighted for type of tissue
  5. same as absorbed dose
A
  1. absorbed dose to an organ or tissue weighted for type of radiation
49
Q

The Health and Safety Executive…

  1. can prosecute a practice under the Ionising Radiations Regulations
    2017
  2. can serve enforcement notices including those which could stop work
    with X-rays
  3. have statutory powers which allow inspectors to visit a practice unannounced
  4. must have issued a registration before work with an x-ray device
    commences
  5. All of the above
A
  1. All of the above
50
Q

. Which of the following is not required in the local rules?

  1. A dose investigation level
  2. An exposure chart containing both local and national diagnostic
    reference levels
  3. Name of the Radiation Protection Supervisor
  4. Systems of work for entry into and work within the controlled area
  5. The identification and description of each controlled area
A
  1. An exposure chart containing both local and national diagnostic