17. ALARA: THE GOLD STANDARD OF RADIATION PROTECTION Flashcards
- What does ALARA stand for?
- As Low As Reasonably Achievable
- this helps to limit the dosages of Radiation Exposure
- What are the 3 Principles for Reducing Radiation Exposure?
- TIME
- an decrease in time = a decrease in radiation - DISTANCE
- an increase in time= a decrease in radiation
- the relation is squared
- this is the most effective method - SHIELDING
- an increase in shielding = a decrease in radiation
- What does the Principle of Optimisation apply to?
- it applies to all circumstances
- it includes soft and hard restrictions
IT ADDRESSES THE CONSIDERATIONS OF:
- fairness
- restrictions
- doses
- risks
- to all individuals
- What are 2 examples of soft restrictions?
- dose
- risk constraints
- What is 1 example of hard restrictions?
- dose limits
- What is Dose Limitation?
- 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
- Where are Dose Limits typically introduced?
- 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
- What is the Effective Dose Limit in:
8.1. Occupational (mSv)
8.2. Public (mSv)
8.1: 20 mSv per year
: this is the averaged over the defined period of 5
years
8.2: 1 mSv in a year
- What is the Annual Equivalent Dose Limit for for Lens
of the eye in:
9.1. Occupational (mSv)
9.2. Public (mSv)
9.1: 20 mSv
9.2: 15 mSv
- What is the Annual Equivalent Dose Limit for for
Skin in:
10.1. Occupational (mSv)
10.2. Public (mSv)
10.1: 500 mSv
10.2: 50 mSv
- What is the Annual Equivalent Dose Limit for for
Hands and feet in:
11.1. Occupational (mSv)
11.2. Public (mSv)
11.1: 500 mSv
11.2: n.a mSv
- What are the two different ways that the system of Radiological Protection organises exposures to individuals?
- BY THE EXPOSURE SITUATION:
- planned
- existing
- emergency
NB: these address all conceivable circumstances - BY THE CATEGORY OF EXPOSURE:
- occupational
- medical
- public
- What are Planned Exposure Situations according to ICRP Report 103?
- 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
- What are Existing Exposure Situations according to ICRP Report 103?
- 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)
- What are Emergency Exposure Situations according to ICRP Report 103?
- 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
- What is an important simplification in the system of Radiological Protection?
- 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
- What is Occupational Exposure according to ICPR Report 103?
- 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
- In which kind of exposure situations can Operating Exposure occur?
- in planned exposure situations
- in existing exposure situations
- in emergency exposure situations
- What is Medical Exposure according to ICPR Report 103?
- 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
- In which kind of exposure situations can Medical Exposures occur?
- in planned exposure situations
- What is Public Exposure according to ICPR Report 103?
- it encompasses all exposures of the public
OTHER than occupational exposures and medical
exposures
- In which kind of exposure situations can Public Exposures occur?
- in planned situations
- in existing situations
- in emergency exposure situations
- What is the Objective of Radiological Protection in Medicine?
TO PROVIDE OPTIMAL PROTECTION TO:
- staff
- patients
- members of the public
- What kind of radiation use can pose a threat to the health of human beings?
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
- Which publication deals with all aspects of Radiation Protection in Medicine?
- ICRP Publication 105
- Radiological Protection in Medicine
- there are also a variety of ICRP publications that are
available for specific fields of Medicine
- What is the purpose of Diagnostic Reference Levels?
- 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
- According to the ICRP, what can the Diagnostic Reference Level be used for?
- 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 - TO PROMOTE THE ATTAINMENT OF A NARROW
RANGE OF VALUES- that represent good practice for a more specific
medical imaging task
- that represent good practice for a more specific
- TO PROMOTE ATTAINMENT OF AN OPTIMUM RANGE
OF VALUES
- for a specified medical imaging protocol
- Who should select the Diagnostic Reference Levels?
- professional medical bodies
- this decision must be made in conjunction with the
National Health and Radiological Protection Authorities
- What should the values of the Diagnostic Reference Levels be based on?
- they should be based on relevant regional, national or
local data
- What should the Diagnostic Reference Levels be applied to?
- 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
- Give 4 examples of the easily measured quantities that the Diagnostic Reference Levels can be applied to?
- The Entrance Surface Air Kerma
(in mGy) - The Dose Length Product
(DLP) - The Dose Area Product
(DAP) - Milliampere Seconds
(mAs)