16. RADIATION HEALTH EFFECTS: SAFETY Flashcards
- When was the most recent set of the fundamental ICRP Recommendations published?
- this was ICRP Publication 103
- it is called the: “The 2007 Recommendations of the
International Commission on Radiological Protection”
- What does “The 2007 Recommendations of the International Commission on Radiological Protection” outline?
- it describes the entire system of Radiological
Protection - it forms the basis for all the relevant EU and
International Legislations
- What does the scope of Radiological Protection include?
- it includes all the exposures to ionising radiation
- these exposures can come from any source
- regardless of the exposure size or origin
THIS INCLUDES:
- Natural Sources of Radiation
- Man made sources of Radiation
- When does the system of protection against radiation apply itself fully?
- when the source of exposure can be controlled
- when the pathways leading to the exposure can be
controlled - a set of fundamental principles will be applied in all
circumstances - this does not mean that there is equal protection
treatment in all the circumstances
- What is a Graded Burden of Obligation?
- this is something that is expected
- it is brought about through regulatory controls and
procedural arrangements - it depends on the level of risk
- it depends on the Flexibility of control
- Which two concepts help to precisely describe the domain of radiological protection control?
- Exclusion
- Exemption
- Why can certain situations be excluded?
- CONTROL IS NOT POSSIBLE
- EG: potassium 40 occurring naturally in the human
body - CONTROL IS OBVIOUSLY IMPRACTICAL
- EG: exposure to cosmic radiation
NB:
- control in these situations is unjustified
- the exempts these situations from regulatory
requirements
- What kind of situations can expereince exemption from regulatory requirements?
- situations in which the effort to control is excessive
compared to the associated risk
- What do National Regulators do?
- they decide what is excluded
- they decide in which circumstances control is
unwarranted
- What is the Primary Aim of the system of radiological protection according to ICRP
Report 103?
- What are the Human Health Objectives of the system of Radiological Protection according to the ICRP Report 103?
- How are Deterministic Efforts preventable?
- by keeping the doses below a specific threshold
- How are Stochastic Effects managed?
WITH STOCHASTIC EFFECTS:
- even a small dose might give rise to a risk of a
condition
THE PROTECTION SYSTEM AIMS TO:
- prevent harm that is preventable
- manage harm that cannot be prevented
- List 2 characteristics of Deterministic Effects?
- They depend on the doses
- There is a threshold limit
- any dose below this limit with have no effect
- List 4 characteristics of Stochastic Effects?
- They are probabilistic
- They have no threshold
- The severity of the effects is not related to the dose
- There is a risk of developing conditions due to
Stochastic effects whenever we are exposed to
radiation
- EG: cancer
- What is the system of Radiological Protection based on?
- Scientific Knowledge
- EG: the Photoelectric Effect
- EG: the Compton Effect
- EG: Pair Production - Ethical Values
- Experience
- What can science give us information to, with regards to Radiological Protection?
- HOW RADIOACTIVE METALS MOVE
- through the environment
- how they move through human bodies once they
have been inhaled or ingested
- HOW RADIATION INTERACTS WITH MATTER
- THE EFFECTS OF RADIATION ON HUMAN HEALTH
- and on the environment
NB:
- all these aspects are important for Radiological Protection
- Why are Ethical Value Judgements necessary in Radiological Protection?
- they help to decide what may be tolerable or
intolerable
THESE ETHICAL VALUE PRINCIPLES INCLUDE:
- Precaution
- Wisdom
- Justice
- Beneficence (the need to do good)
- How does ICRP Publication 103 define Stochastic Effects?
STOCHASTIC EFFECTS INCLUDE:
- cancer
- heritable effects
(these are the effects
that will appear in
future generations)
- What kind of model does the System of Radiological Protection use?
- it uses the Linear No-Threshold (LNT) Model
- it uses this as a basis
- this model is scientifically plausible
- it is not universally accepted as the biological truth
THIS MODEL IS PRUDENT FOR PUBLIC POLICY:
- these policies are aimed at avoiding unnecessary risks
from any kinds of exposures and ionising radiation
- this risk is an estimation
- What does the Linear No-Threshold (LNT) Model assume?
- it assumes that any dose will produce a proportionate
increment in probability - this happens no matter how small the dose is
THE PROBABILITY:
- is one that concerns itself with the chance of cancer or
heritable effects incurring
- How are Deterministic Effects described by ICRP Publication 118?
THE THRESHOLD:
- is the key parameter
in terms of radiological
protection
- What did ICRP Publication 118 focus on when it came to Deterministic effects?
- they focused on estimating the dose thresholds
- this was defined as the dose resulting in 1% of
individuals - these individuals were exhibiting a specified effect
- What does defining a threshold NOT IMPLY?
- it does not imply that there will be no biological effects
that occur at lower doses - it defines the dose above which specified effects
become clinically apparent in a small percentage of
individuals
- What is a Central feature of Radiological Protection?
- calculating the dose of the radiation received
- What are the 3 dose quantities that are used?
- THE ABSORBED DOSE
- this is measured in Grays (Gy)
- it is the dose absorbed by the body
- THE EQUIVALENT DOSE
- this is measured in Sievert (St)
- it is the Absorbed dose x the radiation weighting
factor
- it takes into consideration the relative biological
effectiveness (RBE) of various radiation types - THE EFFECTIVE DOSE
- this is measured in Sievert (Sv)
- it is the Equivalent dose x the tissue weighting factor
- it looks at the sensitivity of the tissue to radiation
exposure
- What can be said about the averaged absorbed dose when it comes to Radiological Protection Applications?
- the absorbed dose is averaged over tissue volumes
- different organs and tissues have different sensitivities
to radiation
- What can be said about the Absorbed Dose at low doses?
- the absorbed dose averaged over a specific organ or
tissue is linked with the radiation detriment for
Stochastic Effects - this has a sufficient accuracy for protection purposes
- What can be said about different ionising levels?
- they have different levels of effectiveness in causing
biological effects
EXAMPLES OF IONISING RADIATION LEVELS:
- Alpha
- Beta
- Gamma
- Neutron
- other varieties of charged particles
- What would happen if all Radiation Effects were deterministic in nature?
- the system of radiological protection could be quite
straightforward - we would be able to simply avoid exposures that
exceed the thresholds as they are potentially
dangerous - exposures below the thresholds would be considered
safe
- What does the Probabilistic nature of Stochastic effects mean?
- it means that there is no clear distinction between the
levels of exposure - we cannot identify which levels are safe and which are
dangerous
- What is the appropriate level of protection from radiation based on?
- it is based on what is deemed acceptable in a given
circumstance - ethical considerations play a role here
- such as justice and beneficence
- What are the 3 Fundamental Principles of the ICPR System of Protection?
- Justification
- Optimisation
- Dose Limitations
- What is the Principle of Justification?
- this means that the
benefits should
outweigh the
detriments for the
patient when we
introduce a new
source of radiation - this also applies when
we remove a risk of
potential exposure
from an existing one - this principle applies
under all circumstances - this principle is the
responsibility of the
radiologists and the
referring doctors
- What is the Principle of Optimisation?
- it demands that the net benefit to society and
individuals should be maximised - there should be a balance between the image quality
and the patient radiation dose - this concept defines the best level of protection under
the prevailing circumstances