17. ALARA: THE GOLD STANDARD OF RADIATION PROTECTION

Question 1

1. What does ALARA stand for?

Answer 1

• As Low As Reasonably Achievable
• this helps to limit the dosages of Radiation Exposure

Question 2

2. What are the 3 Principles for Reducing Radiation Exposure?

Answer 2

1. TIME
   - an decrease in time = a decrease in radiation
2. DISTANCE
   - an increase in time= a decrease in radiation
   - the relation is squared
   - this is the most effective method
3. SHIELDING
   • an increase in shielding = a decrease in radiation

Question 3

3. What does the Principle of Optimisation apply to?

Answer 3

• it applies to all circumstances
• it includes soft and hard restrictions

IT ADDRESSES THE CONSIDERATIONS OF:
- fairness
- restrictions
- doses
- risks
- to all individuals

Question 4

4. What are 2 examples of soft restrictions?

Answer 4

• dose
• risk constraints

Question 5

5. What is 1 example of hard restrictions?

Answer 5

• dose limits

Question 6

6. What is Dose Limitation?

Answer 6

• these limits do not apply to patients
  during their procedures
• this means that there are no private
  limits
• this is because doctor’s have justified this
  exposure
• doctors have ensured that the benefit
  has outweighed the harm and risk
• there are limits for public and
  professional bodies
• these limits cannot be breached

Question 7

7. Where are Dose Limits typically introduced?

Answer 7

• they are introduced into radiological protection
  legislation
• they have penalties that are associated with causing an
  individual to exceed these limits
• dose limits do not apply to all circumstances

Question 8

8. What is the Effective Dose Limit in:

8.1. Occupational (mSv)
8.2. Public (mSv)

Answer 8

8.1: 20 mSv per year
: this is the averaged over the defined period of 5
years

8.2: 1 mSv in a year

Question 9

9. What is the Annual Equivalent Dose Limit for for Lens
   of the eye in:

9.1. Occupational (mSv)
9.2. Public (mSv)

Answer 9

9.1: 20 mSv

9.2: 15 mSv

Question 10

10. What is the Annual Equivalent Dose Limit for for
    Skin in:

10.1. Occupational (mSv)
10.2. Public (mSv)

Answer 10

10.1: 500 mSv

10.2: 50 mSv

Question 11

11. What is the Annual Equivalent Dose Limit for for
    Hands and feet in:

11.1. Occupational (mSv)
11.2. Public (mSv)

Answer 11

11.1: 500 mSv

11.2: n.a mSv

Question 12

12. What are the two different ways that the system of Radiological Protection organises exposures to individuals?

Answer 12

1. BY THE EXPOSURE SITUATION:
   - planned
   - existing
   - emergency
   NB: these address all conceivable circumstances
2. BY THE CATEGORY OF EXPOSURE:
   • occupational
   • medical
   • public

Question 13

13. What are Planned Exposure Situations according to ICRP Report 103?

Answer 13

• this is where radiological protection can be planned in
  advance
• this can be planned before exposures occur
• the magnitude and the extent of the exposures can be
  reasonably predicted

EXAMPLE:
- when you send a patient for an X-Ray

Question 14

14. What are Existing Exposure Situations according to ICRP Report 103?

Answer 14

• these are the situations that already exist when a
  decision on control has to be taken
• there are many types of existing exposure situations
  that may cause exposures
• these exposures are high enough to warrant
  radiological protective actions or at least their
  considerations

EXAMPLES:
- Radon in dwellings
- Radon in the workplace
- Naturally Occurring Radioactive Materials (NORM)

Question 15

15. What are Emergency Exposure Situations according to ICRP Report 103?

Answer 15

• they are unexpected situations that may require
  urgent protective actions
• they can also be longer-term protective actions that
  are to be implemented

EXAMPLES:
- Chernobyl
- Hiroshima
- Nagasaki

Question 16

16. What is an important simplification in the system of Radiological Protection?

Answer 16

• individuals are subject to several categories of
  exposure
• these can be dealt with separately

EXAMPLE:
- radiographers are exposed to radiation sources due to
their work
- they are exposed to environmental sources as
members of the public
- they are exposed to medical sources as patients
∴ the control of exposures in one category is not
influenced by the exposures from the other

Question 17

17. What is Occupational Exposure according to ICPR Report 103?

Answer 17

• it is the radiation exposure of workers
• it is incurred as a result of their work
• this can be reasonably regarded as being the
  responsibility of the operating management

Question 18

18. In which kind of exposure situations can Operating Exposure occur?

Answer 18

• in planned exposure situations
• in existing exposure situations
• in emergency exposure situations

Question 19

19. What is Medical Exposure according to ICPR Report 103?

Answer 19

• it is the exposure of individuals to radiation
• this is for diagnostic, interventional and therapeutic
  purposes

IT CAN ALSO REFER TO:
- the exposures of non-occupational comforters and
carers
- they are exposed when they act as volunteers in
Biomedical Research

Question 20

20. In which kind of exposure situations can Medical Exposures occur?

Answer 20

• in planned exposure situations

Question 21

21. What is Public Exposure according to ICPR Report 103?

Answer 21

• it encompasses all exposures of the public
  OTHER than occupational exposures and medical
  exposures

Question 22

22. In which kind of exposure situations can Public Exposures occur?

Answer 22

• in planned situations
• in existing situations
• in emergency exposure situations

Question 23

23. What is the Objective of Radiological Protection in Medicine?

Answer 23

TO PROVIDE OPTIMAL PROTECTION TO:
- staff
- patients
- members of the public

Question 24

24. What kind of radiation use can pose a threat to the health of human beings?

Answer 24

THE USE OF RADIATION IN:
- Diagnosis (generally imaging)
- Treatment

AS WELL AS IN:
- Medical Procedures that do not fit neatly into just one
of these categories
- EG: fluoroscopically guided procedures

Question 25

25. Which publication deals with all aspects of Radiation Protection in Medicine?

Answer 25

- ICRP Publication 105 - Radiological Protection in Medicine - there are also a variety of ICRP publications that are available for specific fields of Medicine

Question 26

26. What is the purpose of Diagnostic Reference Levels?

Answer 26

- they serve to help in the optimisation of the protection of patients THIS IS ACCOMPLISHED BY: - avoiding Radiation Dose that does not contribute to the Clinical Purpose of the imaging procedure

Question 27

27. According to the ICRP, what can the Diagnostic Reference Level be used for?

Answer 27

1. TO IMPROVE REGIONAL, NATIONAL OR LOCAL DISTRIBUTION - of the observed results for a general medical imaging task - it does this by reducing the frequency of the unjustified high or low values 2. TO PROMOTE THE ATTAINMENT OF A NARROW RANGE OF VALUES - that represent good practice for a more specific medical imaging task 3. TO PROMOTE ATTAINMENT OF AN OPTIMUM RANGE OF VALUES - for a specified medical imaging protocol

Question 28

28. Who should select the Diagnostic Reference Levels?

Answer 28

- professional medical bodies - this decision must be made in conjunction with the National Health and Radiological Protection Authorities

Question 29

29. What should the values of the Diagnostic Reference Levels be based on?

Answer 29

- they should be based on relevant regional, national or local data

Question 30

30. What should the Diagnostic Reference Levels be applied to?

Answer 30

- they should apply to easily measured quantities - these quantities are reasonable relative indicators of the patient dose - this helps to see if a practice is safe

Question 31

31. Give 4 examples of the easily measured quantities that the Diagnostic Reference Levels can be applied to?

Answer 31

1. The Entrance Surface Air Kerma (in mGy) 2. The Dose Length Product (DLP) 3. The Dose Area Product (DAP) 4. Milliampere Seconds (mAs)