Biodosimetry in Mass Casualty
Events
Lecture
Module 10
IAEA
International Atomic Energy Agency
What is a mass casualty event?
Involvement of a large number of people
needing to be assessed into:
1. Exposed and requiring medical treatment
2. Exposed but below the level needing
treatment
3. Worried well
• A multiple casualties event is one that
exceeds the response capability of the local
responders
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Planning
Important points:
• Learn from previous experience
• Envisage potential scenarios
• Maintain a review of medical / technical
resources
• Have plans prepared
• Exercise
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Radiation emergencies (1)
Accidental
Broadly three types:
1. Reactor emergencies - breach of fuel due
to loss of coolant
2. Criticality - uncontrolled fission
3. Orphan sources - lost or stolen
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Radiation emergencies (2)
Malicious
Again, three broad types:
1. Radiological exposure devices
2. Radiological dispersal devices
3. Improvised nuclear devices
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Medical triage (1)
The immediate sorting of casualties into
medical treatment priorities
Based on:
• Obvious signs (early prodromal effects)
• Patient’s account (location, timing etc)
• Associated trauma (treating life threatening
injury takes precedence over irradiation)
• Information on the nature of the event
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Medical triage (2)
The initial sorting of irradiated persons is to
establish:
• Those requiring no treatment
• Those probably needing treatment after
further observation
• Those needing treatment immediately
• Those beyond medical help
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Medical triage (3)
• Treatment is started based on signs and
symptoms; not on dose estimates
• Dose triaging needs to be only approximate:
<1 Gy; 1-2 Gy; 2-4 Gy; 4-6Gy; >6Gy
• Based on early clinical responses there will
be false positives and false negatives
• Biodosimetry can more precisely place
persons into dose groups
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Biodosimetry capacity
Definition: A multiple casualties event that
exceeds the response capability of the local
responders
• Biodosimetry labs are rare
• Many countries have no lab
• Very few countries have more than one lab
• Individual biodosimetry labs tend to be small
with few specialist trained staff
The surge capacity is limited
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Some examples
Some events where mass biodosimetry
experience was gained.
Place
Year
No. of persons
Chernobyl 1986
> 100, 000
Goiania
1997
~250
Concepcion 2005
~230
Dakar
2006
~60
Tokaimura 1999
~40
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Biodosimetry: Dealing with a surge
Requirement: To speed up the throughput of
case investigations
Response: Four broad approaches:
• Triage dicentric scoring
• Change to a different assay endpoint
• Automation
• Networking
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Triage scoring
Several approaches:
• Reduce the number of cells scored per
patient for dicentrics
• Use the ‘Quickscan’ method of scoring
dicentrics
• Reduce the number of cells scored for
micronuclei
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Reduced dicentric scoring
Strategy:
• Ideally score 50 cells (or 30 dicentrics)
• Confer with physicians; identify conflicts
and prioritize them for resolution
• Later - less urgently increase scoring to
improve data for:
1. impaired bone marrow management
2. scientific interest - epidemiology
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Quickscan dicentric scoring
Strategy:
• Look at metaphases that appear to be
complete without doing a count
• Spend less time evaluating each metaphase.
• Count the dicentrics
This approach to scoring reduces microscopy
time by a factor of ~6
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Reduced micronuclei scoring.
Strategy:
• Culture cells (72h) for the CBMN assay
• Stain with acridine orange (fluorescence
microscope needed)
• Score 200 binucleate cells per patient
This approach will detect radiation doses in
excess of 1 Gy
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Automation
Various stages can be automated:
• The ‘wet work’ – cell culturing, fixing, slide
making and staining
• Metaphase and binucleate cell detection
• Image capture and storage
• Dicentric and micronucleus ‘hunting’
software.
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Operator review at an automated
microscope
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Automatic dicentric hunter
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Automatic micronucleus hunter
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The concept of an automated lab
Blood handler
Incubator
Cell harvester
Spreader
Control computer
Satellite scoring station
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Metaphase finder
Slide
Auto stainer
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Networking
This can take several forms:
• Sharing blood samples among labs for the
culturing and scoring
• Sharing just the scoring among labs by
sending out fixed cell suspensions or slides
or by telescoring
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Existing networks
Geographical groupings:
• Single countries: Canada, France, Japan,
Republic of Korea
• Regions: Latin America, European Union
• World-wide: RANET
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Mass casualties - Summary points (1)
• We have actual experience from responding
to mass accidents
• Biodosimetry must work in close
collaboration with the medical response
• Biodosimetry acts as a secondary triage
after initial clinical assessment
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Mass casualties - Summary points (2)
•
•
•
•
•
•
Labs are small with limited surge capacity
Provision has been made to deal with surges
Other assays than the dicentric are available
Automation is well established in many labs
Biodosimetry can operate in a triage mode
Assistance through networking is set up
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Mass casualties - Summary points (3)
• Biodosimetry community can mount
response proportionate to size of most
envisaged events
• It can comfortably handle tens to hundreds
of cases
• Possibly a few thousands
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