IRMER

1.

1 point

IRR99 requires

All exposures to be restricted as far as reasonably practicable

All staff to be monitored for radiation exposure

All exposures to patient to be within diagnostic reference levels

Doses to patients to be recorded

All exposures to be restricted within Dose Limits

2.

1 point

Concerning Controlled Areas

Pregnant patients are not permitted to enter Controlled Areas

Are subject to written arrangements to control access

Access is permitted for employees only

Are monitored by the Radiation Protection Adviser

Non-classified workers are not permitted to enter Controlled Areas

3.

1 point

In an intra-oral X-ray set, the purpose of the collimator is to...

Focus the X-rays

Restrict X-ray beam to chosen area

Protect the operator from scatter

Remove the lower energy radiation from the beam

Absorb scattered radiation

4.

1 point

The National Diagnostic Reference Dose for intra-oral radiology is 2.1 mGy.
This is expressed in terms of:

Committed dose

Absorbed dose

Dose-width product

Equivalent dose

Effective dose

5.

1 point

What is a Diagnostic Reference Level (DRL)?

Radiation dose which should not be normally exceeded for a standard exposure

Is the optimum dose from a procedure

Defines the risk to the patient

Prescribed radiation dose to the patient

Applies to any patient having an x-ray

6.

1 point

The useful interaction of photons with matter when taking intra-oral x-rays is:

Photo-electric absorption

Pair production

Characteristic radiation

Compton or inelastic scatter

Elastic recoil

7.

1 point

A female member of staff:

Must wear a lead protective apron

Must tell her colleagues if she is more than 6 months pregnant

Must tell her employer if she is in the first trimester of pregnancy

Must inform her employer in writing if she is pregnant

Must not work with X-ray equipment

8.

1 point

Under IRMER

The Practitioner does not require theoretical training

Operators do not require theoretical training

The Referrer must be appropriately trained

The Operator must have practical training

Students under supervision must be trained before carrying out exposures

9.

1 point

Bremsstrahlung or ‘braking radiation’ is:

Produced when an x-ray photon strikes a Calcium atom

The primary cause of image noise

The major source of photons is in X-ray tube

Only produced at tube voltages above 50 kv

Emitted at a particular (discrete) wavelength

10.

1 point

Regarding Justification

The Practitioner is responsible for justifying the exposure

The exposure is approved by the Practitioner and justified by the Operator

The Referrer is responsible for justifying the exposure

The exposure is justified by the Referrer and authorised by the Practitioner

The Operator is responsible for justifying the exposure

11.

1 point

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

As defined in the Local Rules

At the extent of the exposure cable

2.5 metres

1.5 metres

2 metres

12.

1 point

The x-ray beam should be…

Perpendicular to the tooth and image receptor to prevent distortion

As close to the patient as possible

Produced from a large focal spot

Positioned perpendicular to the floor

13.

1 point

Dose optimisation is

The process by which maintenance engineers assess the quality of the equipment

The process by which the smallest dose to the patient is ensured

The process by which the best possible image quality is ensured

The process by which a diagnostic relevant image is obtained at the lowest dose

The process by which equipment is maintained

14.

1 point

The use of rectangular collimation is recommended in the Dental Guidance Notes of the NRPB.
Rectangular collimation:

Helps align the tube to the film

Is mandatory

Holds the film in the correct position

Ensure object and receptor are in the correct relationship

Reduces the patient - dose by around 40%

15.

1 point

Under IRMER Optimisation

Is ensuring the dose is as low as achievable and image quality is acceptable

Is ensuring the patient dose is less than the Diagnostic Reference Level

Is ensuring the required diagnostic information is obtained

Is ensuring the patient dose is low

Is ensuring the image quality is high

16.

1 point

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

60 - 70 kV

70 - 80 kV

80 - 90 kV

90 - 100 kV

50 - 60 kV

17.

1 point

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

Controls the HT circuit for the set

Is usually set for each exposure by means of the control box

Is the Mega Amp current

Is set higher for a bite-wing than for a periapical radiograph of an upper molar

Controls the number of electrons produced at the filament

18.

1 point

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

1.5mmAl

0.1mmPb

1.0mmPb

2.0mmCu

2.5mmAl

19.

1 point

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

0.1 Sv

10 cGy

25 mGy

3.2 mSv

2 mGy

20.

1 point

An x-ray of a female patient of child-bearing age

Can only be undertaken within 10 days of the last menstrual period

Must not be undertaken if she is pregnant

Must be given a lead apron to wear over her abdomen

Is prohibited under the Ionising Radiations(Medical Exposure ) Regulations unless a check is made if she is pregnant

Must be undertaken in accordance with local written procedures

21.

1 point

Regarding effective dose:

Expresses the probability of cancer incidence in a population

Is a measure of the chance a patient has to die from cancer

Should be calculated for each examination undertaken

Expresses a cancer mortality risk to an individual

Expresses the radiation dose from an individual exposure

22.

1 point

Image unsharpness is not affected by

Patient movement

Increase in kVp

Grain size in film emulsion

Focal spot size

Geometric magnification

23.

1 point

Regarding the Bremsstrahlung process

The incident electron collides with K-shell atomic electron

An incident electron interacts with the nucleus releasing an x-ray photon

Is dependent on the binding energy of the atomic electrons

Results in the ejection of an atomic electron

Describes how electrons move within atomic shells

24.

1 point

The blackening of an X-ray film or greyscale value on an X-ray image depends on:

The length of the exposure setting

All of the above

The mA setting of the intra-oral set

The number of X-ray photons interacting with the receptor B The length of the exposure setting C The mA setting of the intra-oral set D The distance from the end of the collimator tube to the patient E All of the above The number of X-ray photons interacting with the receptor B The length of the exposure setting C The mA setting of the intra-oral set D The distance from the end of the collimator tube to the patient E All of the above The number of X-ray photons interacting with the receptor B The length of the exposure setting C The mA setting of the intra-oral set D The distance from the end of the collimator tube to the patient E All of the above The number of X-ray photons interacting with the receptor B The length of the exposure setting C The mA setting of the intra-oral set D The distance from the end of the collimator tube to the patient E All of the above The number of X-ray photons interacting with the receptor

The distance from the end of the collimator tube to the patient

25.

1 point

The Stochastic Effects of lonising Radiation:

Cause no biological damage at low doses

Have a safe threshold

Can result in radiation-induced erythema or burns

Occur as the result of chance events

Follow a linear-quadratic relationship

26.

1 point

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

Operates at around 50,000 Volts

Varies according to the exposure setting

Is in the 65-70 kVp range

Is usually around 65,000 kV

Is usually about 6.5 - 7.5 mA

27.

1 point

Deterministic effects of ionising radiation:

Are normally seen in routine dental exposures

Have a threshold dose below which they do not occur

Are a necessary side effect of ionising radiation in dental practice

Include hereditary effects in future generations

Cannot be predicted before the exposure has happened

28.

1 point

Regarding Justification

Examinations on children under 5 are not justified

Does not apply to asymptomatic exposures

Justification must be carried out for every exposure

Examinations on pregnant patients are not justified

Justification is not required for routine x-rays

29.

1 point

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

Enables the beam to be centred to the film

Increases magnification of the image

Is not appropriate for patients with disabilities

Periodontal bone levels are poorly represented

Is not the technique of choice routinely

30.

1 point

The Frankfort baseline is…

The relative position of the tube, cassette and patient during OPT examinations

A radiographic plane that bisects the first upper molar

A radiographic plane that divides the face symmetrically from the crown of the head to the tip of the mandible

A radiographic plane that extends from the external auditory meatus to the lower orbital margin

A radiographic term that describes normal anatomical appearances viewed on an OPT

31.

1 point

Regarding absorbed dose:

Absorbed dose is defined only at the surface of the tissue we are interested in

The correct unit for absorbed dose is the Sievert

Absorbed dose is a measure of the risk of exposure ionising radiation

Absorbed dose is a measure of the energy deposited in tissue per unit mass

For the same amount of Xrays falling on tissue, the absorbed dose will be the same irrespective of tissue type

32.

1 point

The Ionising Radiation (Medical Exposure) Regulations 2000:

Are intended to protect patients

Protect members of the Dental Team

Protect members of the public

Place a limit on the number of x-rays a patient can receive

Are an Approved Code of Practice

33.

1 point

Collimation of the X-ray beam…

Should be rectangular

Increases scattered radiation

Is not necessary

Should be circular

Increases the volume of exposed tissue

34.

1 point

Regarding the Photoelectric effect

May result in scattered radiation

The incident photon is completely absorbed

The effect is independent of atomic number

The probability of photoelectric absorption does not depend on photon energy

The incident photon interacts with a free atomic electron

35.

1 point

Compton (inelastic) scatter:

Helps build contrast in the resultant image

Causes blurring of the resultant image

Helps tissue discrimination

Causes noise within the X-ray image

Is the primary photon interaction at energies below 70kV

36.

1 point

Stochastic radiation effects

Are not present in dental radiography

Can be seen in patients a few weeks after exposure

Are assumed to follow a linear no threshold relationship to dose

Are likely to be similar comparing a dental OPG Xray and average annual background radiation

Have a threshold

37.

1 point

The Ionising Radiation regulations 1999

Protect members of the public

Protect members of the workforce

Are statutory legislation

Are enforceable in law

All of the above

38.

1 point

When an X-ray beam interacts with the target (patient):

Some of the radiation passes through unchanged

Some of the photons are absorbed

Some of the X-rays are scattered

The x-ray beam is said to have been attenuated

All of the above

39.

1 point

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

150mm

200mm

50mm

250mm

100mm

40.

1 point

In an intra-oral X-ray set, excess heat:

All of the above

Is caused because X-ray production is inefficient

Is conducted away by the copper block

Is radiated away from the outer case

Is dissipated by convection in the oil surrounding the tube

41.

1 point

Regarding damage to the DNA molecule by ionising radiation

Cells may mutate

Is caused by direct interaction with ionising radiation

Cells may repair

Is caused indirectly by free radicals

All of the above

42.

1 point

The Radiation Protection Supervisor (RPS):

Isn’t usually required in a hospital/dental school

Must be a dentist

Must be identified in the practice information in leaflet

Is usually either the Practice Administrator or Senior Dental Nurse

Must have received appropriate training

43.

1 point

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

The tungsten target

The cathode B he cathode B he cathode B he cathode B he cathode B The filament

The focussing cup

The cathode

The aluminium filter

44.

1 point

The deterministic or non-stochastic effects of Ionising Radiation:

Have no threshold

Occur according to the laws of chance

Are independent of the amount of radiation received

Are concerned with the risks of inducing cancer at low doses

Are dose-dependent

45.

1 point

X-ray production in a diagnostic x-ray tube is approximately

52% efficient

5% efficient

99% efficient

1% efficient

95% efficient

46.

1 point

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

Clearly demonstrates a hormesis effect

Follows the linear-no-

Is non-existent at very low doses

Has a ‘dose threshold’

Is independent of the dose received

47.

1 point

The role of the Radiation Protection Supervisor:

Is to ensure that Local Rules are being followed and enforced

Is to ensure the Register of Training is kept updated

Is to write Local Rules for the Practice

Is to ensure X-ray equipment has been regularly serviced

Is to ensure Radiation Badges are changed monthly

48.

1 point

In an intra-oral X-ray set, the purpose of the aluminium filter is to....

Help create a sharper image

Protect the operator

Preferentially attenuate low energy X-rays

Prevent backscatter from fogging the image

orb scattered radiation B Absorb scattered radiation

49.

1 point

Patient dose is not affected by

Increasing the Focus to Skin Distance

Increasing the tube filtration

Using a rotating anode target

Increasing tube potential (kVp)

Decreasing exposure time