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The Medical Treatment of Casualties
Following a Radiation Accident at AWE
by
Christopher Stewart Jones
Department of Physics
Faculty of Electronics & Physical Sciences
University of Surrey
and
AWE plc
Aldermaston
Berkshire, UK
September 2009
A dissertation submitted to the Department of Physics,
University of Surrey, in partial fulfilment of the degree of
Master of Science in Radiation and Environmental Protection
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Abstract
Any nuclear licensed site must have plans to deal with the processing and medical treatment
of casualties from radiation accidents. These casualties may have been irradiated by an
external radiation field or externally contaminated. Alternatively or in addition, they may
have received an intake of radioactive material through inhalation, ingestion or absorption
through wounds or unbroken skin. This project examines the recommended procedures and
treatments for such casualties, paying particular attention to the treatment of accidents
involving uranium, plutonium and americium. Skin decontamination, wound excision, whole
lung lavage, DTPA and sodium bicarbonate are among the recommended treatments. Where
possible, these treatments are reviewed against any experimental evidence to verify their
effectiveness and risks, but it is found that in many cases there is a lack of high quality
research and information. However, it is established that all the recommended treatments
are relatively safe and all but one can definitely be recommended for use at potential
committed effective doses greater than 200mSv, and possibly recommended between 20
and 200mSv depending on the exact case. The only exception to this is lung lavage, which is
recommended for intakes leading to lung doses above 6Gy-Eq. The plans for processing and
treating casualties from radiation accidents at the Atomic Weapons Establishment (AWE) are
then detailed by considering AWE’s response to three accident scenarios. In a comparison
with the recommended methods, it is found that AWE is entirely consistent with industry
best practice.
Acknowledgements
I would like to express my gratitude to my supervisors Derek Bingham, Dominic Jones and
Nick Lewis for their help, guidance and support throughout this project. A massive thank you
too to Helen Day for her support throughout my MSc and tireless efforts to ensure the
graduate health physicists have the best possible training and start to their careers.
I would also like to thank all those at AWE who gave up their time to provide me with
information for this project; Brian Burgess, Graeme Burt, Craig Morrissey, Fiona Dagless,
John Bradshaw, Dave Burnand, Jane Hollies, David Green, Gordon McCabe, Vicky Cottrell
and the nurses at TMS.
Many thanks to my fellow students, Tristan Nicholas, Nicky Kay and Jonathon Gray who have
been there to advise, suggest and provide distraction when it was needed, and to Paddy
Regan and Alexia Smith at Surrey University for all their help and assistance throughout my
MSc.
Finally, my eternal thanks, love and gratitude to my family for all their love and support with
whatever I do, and to Sarah for putting up with me getting far too excited about physics far
too often.
Table of Contents
1
2
Introduction ......................................................................................................................... 1
Background Theory .............................................................................................................. 2
2.1
Radiobiology .......................................................................................................................... 2
2.2
Dangers of Cell Irradiation ..................................................................................................... 3
2.2.1
Dosimetric Units ............................................................................................................ 3
2.2.2
Deterministic effects ..................................................................................................... 4
2.2.3
Stochastic effects .......................................................................................................... 6
2.3
Exposure Routes .................................................................................................................... 7
2.3.1
External exposure routes .............................................................................................. 7
2.3.2
Internal exposure routes ............................................................................................... 8
2.3.3
Internal biokinetics of some radionuclides of interest ............................................... 10
2.4
Objectives of Medical Treatment ........................................................................................ 12
3
Literature Review of Recommended Medical Treatments .................................................... 13
3.1
General procedures to deal with an accident victim with combined injuries ..................... 13
3.1.1
Immediate procedures at accident location ............................................................... 13
3.1.2
Treatment decisions .................................................................................................... 14
3.2
Dealing with external contamination .................................................................................. 16
3.2.1
Decontamination of burns .......................................................................................... 17
3.3
Treatment of Irradiation Injuries ......................................................................................... 17
3.3.1
Whole Body (Acute Radiation Syndrome)................................................................... 17
3.3.2
Localised Radiation Injuries......................................................................................... 18
3.3.3
Radioprotectors........................................................................................................... 19
3.4
Dealing with radioactive material in wounds ...................................................................... 20
3.5
Dealing with internalised contamination of specific radionuclides ..................................... 21
3.5.1
Soluble Plutonium/ Americium ................................................................................... 21
3.5.2
Insoluble Plutonium/ Americium ................................................................................ 24
3.5.3
Uranium....................................................................................................................... 25
3.6
Summary of Treatments and Risks ...................................................................................... 26
4
Dealing with casualties in radiation accidents at AWE ......................................................... 27
4.1
Contaminated wound scenario ............................................................................................ 28
4.1.1
The Scenario ................................................................................................................ 28
4.1.2
The Response .............................................................................................................. 28
4.2
Containment failure scenario leading to contamination of skin and/or inhalation ............ 33
4.2.1
The Scenario ................................................................................................................ 33
4.2.2
The Initial Response .................................................................................................... 33
4.2.3
Decontamination of Personnel ................................................................................... 34
4.2.4
Treatment of Suspected Inhalation............................................................................. 35
4.2.5
Follow-up..................................................................................................................... 36
4.3
Mass casualty scenario ........................................................................................................ 38
4.3.1
The Scenario ................................................................................................................ 38
4.3.2
Evacuation Centres...................................................................................................... 38
4.3.3
Irradiated casualties .................................................................................................... 39
4.3.4
Grossly contaminated casualties................................................................................. 40
4.3.5
General monitoring of evacuees ................................................................................. 40
5
Conclusion ......................................................................................................................... 43
Glossary of Abbreviations and Acronyms .................................................................................... 46
References ................................................................................................................................. 47
Appendices A, B, C
1 Introduction
The detrimental health effects of ionising radiations were discovered in 1896, shortly after
the phenomena themselves1 and in today’s health and safety conscious society, the legal
and moral impetus to make all exposures to ionising radiation as low as reasonably
practicable (ALARP) means that it is very rare for people to receive even relatively small
unplanned doses. However, it is prudent, as well as a legal requirement, to be prepared for
occasions when, despite best efforts to minimise their likelihood, accidents and
emergenciesa lead to people receiving a large dose of radiation. 2
In such circumstances it is important to have plans for how such ‘radiation casualties’ –
those irradiated, externally contaminated or who have received an intake of radioactive
material - will be handled and treated; both in terms of the actions of emergency responders
and medical staff, and in terms of possessing knowledge of medical treatments that can help
to reduce the dose received and/or the severity and likelihood of subsequent health effects.
This report aims to review the plans for the handling and treatment of radiation casualties at
the Atomic Weapons Establishment (AWE), by comparison with recommended methods and
treatments from literature and the scientific theories and evidence which support such
recommendations.
AWE is tasked with the manufacture and support of the United Kingdom’s Nuclear Deterrent
and is located on two sites; Aldermaston and Burghfield, situated in Berkshire, UK. Both
locations contain nuclear licensed sites and house facilities for the manufacture, processing,
storage, decommissioning and waste management of radioactive materials. Because of the
nature of the work, the radioactive materials most commonly handled are plutonium and
uranium, and the bulk of the report will focus on the response to accidents involving these
elements. This project will only examine AWE’s response to radiation casualties on-site and
so, although the medical treatments described in this project are equally valid for members
of the public as for workers (although care must be taken when treating children), the care
of the public following a radiation emergency is not discussed.
a
According to the Radiation (Emergency Preparedness and Public Information) Regulations (REPPIR) 20012, a
‘radiation accident’ is any event “where immediate action is required to prevent or reduce the exposure to ionizing
radiation of employees or any other persons”. The term ‘radiation emergency’ is used specifically for large accidents
that are likely to result in members of the public being exposed to ionising radiation. In this report, the word
‘accident’ will be used to refer to all types and sizes of radiation accident.
1
2 Background Theory
2.1 Radiobiology
Ionising radiation traversing living cells can interact with biomolecules, either directly (the
radiation itself ionises the molecule), or indirectly (the radiation creates free radicals
elsewhere in the cell which chemically attack the biomolecule)3. Either way, the energy
deposited is sufficient to break chemical bonds and damage biomolecules4.
Although damage to any part of the cell could be detrimental, many studies have shown that
the nucleus, and in particular DNA, is the critical target for determining the long term
viability of the cell after irradiation1. Because of its double helix structure, DNA is actually
more radio-resistant than many molecules, but its unique role of storing genetic information
means that any damage has a much greater impact on the cell than damage to other
macromolecules. Good repair mechanisms for simple DNA damage such as single strand
breaks and base damage mean that, although relatively rare (less than 1 in 25 lesions),
double strand breaks are the most likely cause of lasting damage to the DNA. If a repair is
not completed perfectly, the DNA will be left mutated, either on a molecular level (a small
section of the DNA code is changed by point mutations, insertions or deletions of the base
sequence) or on a chromosome scale (where the structure of the chromosome is altered,
forming new shapes such as dicentrics or causing the translocation of large sections of the
DNA between chromosomes)3.
Depending on the extent of the damage to the DNA, the original damage or these
subsequent mutations can cause mitotic death (where the cell is unable to undergo mitosis
and so cannot produce new cells), apoptosis (where the cell brings about its own death), or a
cell which is able to continue to divide but with some mutation which is copied into each
progeny. It is these outcomes - cell death or permanent genetic mutation - which lead to the
clinical symptoms of ionising radiation exposure1, discussed in section 2.2 below.
It is worth noting that the concept of ‘cell death’ normally refers to the inability of a cell to
undergo mitosis; it may still be able to continue to perform other functions. On average,
about 2 gray (Gy) is required to cause this reproductive death, while more than 25Gy is
required to stop all cell functions. This has important consequences for severity of acute
radiation syndrome (ARS), also discussed below1.
2
2.2 Dangers of Cell Irradiation
Most adverse health effects of radiation exposure can be grouped into two categories:
deterministic effects and stochastic effects5. However, the International Commission on
Radiological Protection (ICRP) recognises that some health effects are not yet sufficiently
well understood to be assigned to either category5.
2.2.1 Dosimetric Units
The fundamental quantity in dosimetry is the absorbed dose, the amount of energy
deposited by ionising radiation per unit mass, which is expressed in joules per kilogram. The
special name of the unit is the gray (Gy)6, where 1 Gy = 1 Jkg-1. However, it is found that this
quantity alone is not sufficient to estimate the biological effect of a radiation exposure
because other factors such as radiation type, radiation energy, the radiosensitivity of the
target tissue and dose rate influence this result7. The quantity ‘relative biological
effectiveness’ (RBE) is used to compare the absorbed dose of radiation required to produce
a given biological end-point for a particular set of conditions and the absorbed dose required
to produce the same end-point for reference conditions.
For the purposes of radiological protection, the ICRP5 established the quantity ‘effective
dose’, which attempts to express the long term biological harm done by small radiation
exposures by multiplying the absorbed dose by different weighting factors for each radiation
type and target organ/tissue. These weighting factors are loosely based on the RBE for each
type of radiation. The unit used for equivalent dose is the sievert (Sv). However, because the
biological end point used to calculate the weighting factors is long term stochastic effects,
the effective dose formulation should not be used for short term deterministic effects;
studies show that it is likely to overestimate the extent of such clinical effects 5.
Therefore, the need for an equivalent system for deterministic effects has been identified
but there is currently no universally agreed framework in place. In section B.2.2 of
publication 103, the ICRP5 state that the sievert should not be used for deterministic effects,
and instead the absorbed dose should be weighted by the RBE for the radiation type and
particular biological end-point of interest to produce a value for comparative purposes. They
state that this weighted value should still be expressed in gray. Similarly, the International
Commission on Radiation Units and Measurements (ICRU), in conjunction with the
International Atomic Energy Agency (IAEA), have defined7 the quantity isoeffective dose,
3
which is their name for the product of RBE and absorbed dose, and like the ICRP state that it
should be expressed in gray. However, using the same unit as absorbed dose for isoeffective
dose would appear to create a problem of potential confusion between the two quantities.
To tackle this problem, the National Council on Radiological Protection (NCRP) 8 have created
the quantity gray-equivalent, measured in units of gray-equivalent (Gy-Eq), also defined as
the product of the appropriate RBE and the absorbed dose in gray. Finally the Medical
Internal Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine has also
adopted the term ‘isoeffective dose’ but recommended the adoption of the new unit for the
quantity, the barendsen (Bd)9.
Despite current confusion over names for quantities and units, it is clear that all parties are
agreed that the effective dose and its unit, the sievert, should not be used for deterministic
effects. Instead a different quantity; the product of the RBE for the particular end-point in
question and the absorbed dose should be used. Generally in this report the ICRP/ ICRU
convention of using the unit ‘gray’ for both absorbed and isoeffective dose will be used,
although occasionally the NCRP format of calling both this quantity and its unit ‘grayequivalent’ will be used where it is necessary to distinguish isoeffective from absorbed dose.
2.2.2 Deterministic effects
Deterministic effects are predominately due to the killing or malfunction of a large number
of cells within a given tissue, to the extent that the tissue is unable to function to the level
required by the body. As such, the induction of such tissue reactions is characterised by a
threshold dose, below which there is no clinical effect (as not enough cells have been
affected to notably reduce the tissue function) and above which the severity of the effect
increases with dose (as an increasing fraction of the tissue is killed).
The clinical conditions arising from such effects, which are caused by large, acute doses, can
be divided into ARS and other deterministic effects.
2.2.2.1 Acute Radiation Syndrome
ARS consists of four stages; prodrome, latency, illness and recovery/ death10 and has a whole
body dose threshold of around 1Gy. The prodromal stage occurs seconds to hours following
exposure; higher doses lead to faster onset and more severe symptoms. These symptoms
include nausea and vomiting, malaise, fatigue, increased temperature and diarrhoea. These
prodromal symptoms are followed by a latent period, during which the casualty will feel
4
relatively well. The larger the dose, the shorter this period will be. In the original exposure a
number of stem cells will have been killed; during the latency period existing blood cells and
gut epithelial cells naturally die, but the ability of the body to replace these cells may have
been compromised. The victim therefore appears relatively healthy, until affected cell
populations suddenly become dangerously low. The severity of the next stage will depend
on how many of the stem cells have been killed10.
The illness stage is categorised into different syndromes depending on the clinical
symptoms, which in turn depend on the original dose. At between 1-6Gy whole body dose
Hemopoietic Syndrome will occur around 30 days after exposure; it is caused by the
depression or ablation of the bone marrow stem cells that produce new blood cells.
Following the latency period, the number of blood cells will have dropped dangerously low,
leaving the patient at high risk of infection and uncontrolled bleeding. Without medical
attention, 50% of the population will die within 60 days following a whole body dose of
about 3.5Gy1. With good quality medical treatment, this value rises to around 7Gy.
At between approximately 6 and 12Gy whole body dose, of more immediate concern than
the blood cell count is the death of gut stem cells, leading to Gastrointestinal Syndrome,
which occurs around 7 days after exposure. The loss of gut stem cells means cells in the wall
of the gut are not replaced and the gut lining breaks down. This leads to uncontrollable
bleeding into the intestine, septicaemia, diarrhoea and dehydration. This syndrome is much
harder to treat and it is unlikely that a casualty will survive – no-one has ever recovered after
more than 10Gy whole body dose1.
Greater than around 20Gy whole body dose10 the patient will likely get Cerebrovascular, or
Central Nervous System, Syndrome. This syndrome is not well understood, but very quickly
leads to unconsciousness, coma and death within a matter of hours as the nervous and
circulatory systems fail.
2.2.2.2 Other Deterministic Effects
These can normally be seen when more localised doses are received. The most common
local radiation injuries are skin effects. A high skin dose would lead to irritation and
tenderness, followed by erythema (radiation burn), oedema and epilation within 2 weeks at
skin doses of 3Gy or more. 10 to 15Gy would result in blistering, ulceration and peeling
within a month11. Very high doses (>15Gy) can cause skin necrosis12.
5
As well as skin effects, doses of 2Gy or more to the lens of the eye can cause cataract
formation in the long term, or doses of 20Gy+ can cause acute injuries such as keratitis.
Gonad irradiation can cause infertility of both men and women from doses as low as
300mGy11. Finally, there is data from radiotherapy patients to suggest that permanent, long
term damage to the heart and lungs, including pulmonary fibrosis and cardiovascular
disease, can be caused by large doses13.
2.2.3 Stochastic effects
Stochastic effects occur following the mutation of genetic information without subsequent
cell death. Since a mutation can be caused by just one occurrence of radiation damage to
DNA, it is currently believed that these effects have no threshold dose. Instead, the ICRP 5
currently use the linear, no-threshold model (LNT) which states that the likelihood, but not
the severity, of the effect occurring increases linearly with dose. The validity of this model,
particularly at low doses, continues to attract much criticism but for purposes of radiological
protection ICRP and the United Nations Scientific Committee on the Effects of Atomic
Radiation (UNSCEAR) believe it is currently justified by the weight of evidence and its ease of
use. It is increased risk of stochastic effects that is predominantly guarded against by day-today radiological protection activities and principles such as keeping doses ALARP.
The main two examples of such stochastic effects are cancer and heritable disease. Current
radiobiological theory states that radiological mutation is only the starting point for
carcinogenesis; it takes several more random mutations for a cell to become malignant. This
explains why cancer does not generally appear for years following exposure, but also makes
it very hard to pinpoint radiation exposure as the cause of the cancer. Current
epidemiological data, mainly from the Japanese bomb survivors, gives an estimate of a
lifetime cancer risk at low doses and low dose rates of 4.1%Sv-1 for the adult population5.
ICRP have recently downgraded5 the heritable disease risk as the number of generations
required for genetic diseases to reach equilibrium in the population had been
underestimated. The risk coefficient is now only 0.1%Sv-1 for the whole population,
significantly lower than the cancer risk. However, the overall message should be that all
exposures carry a risk of long term health detriment to the individual and future
generations, and so should be avoided with precautions proportional to the risk.
6
2.3 Exposure Routes
Knowledge of the exposure routes through which the body can receive a radiation dose
assists with the planning of the engineering, administrative and personal protective
equipment (PPE) controls which ordinarily protect people from exposures, the planning of
what medical treatments to use if an exposure does occur, and the design of new
treatments that reduce the effects of an exposure11.
2.3.1 External exposure routes
External exposure situations are defined as when the source of the ionising radiation is
outside the body. These situations normally fall into two categories; irradiation and external
contamination10. Note that it is rare that humans will receive a large dose from high-LET
(linear energy transfer, such as alpha) radiation from external sources as these radiations
will be stopped by clothing or layers of dead skin before they are able to reach living tissue 6.
Therefore most of the dose from irradiation accidents will come from electromagnetic
radiation or neutrons, although a large skin dose from beta particles is possible.
2.3.1.1 Irradiation by beta and electromagnetic ionising radiation
Irradiations occur when the individual is within a radiation field produced by a remote (not
in contact with body) radioactive source or criticality event, or by equipment that produces
ionising radiation, such as an X-ray set. Beta and electromagnetic ionising radiation
exposures are characterised by the exposure lasting only as long as the individual is in the
field – if the field is turned off, shielded, or the person moves away, they do not receive any
more dose11.
This means that there is no contamination issue when treating a casualty - they may have
received a large dose but once away from the field there is no danger to emergency
responders or medical staff.
2.3.1.2 Irradiation by neutrons
When irradiated by neutrons, there is a probability that some nuclei in an individual will
capture a neutron and change into another type of nucleus which may be radioactive 10. This
process is known as activation, and will result in the individual continuing to receive a dose
even once they have left the neutron field. They will also irradiate people around them, and
so a person who has been exposed to a large neutron flux may be a notable risk to medical
7
staff and first responders. The amount of activation in most cases will be negligible, but in
situations where large neutron doses occur, such as during a criticality, calculations suggest
that an individual may become activated to a level of tens of megabecquerels14, mainly from
sodium-24, calcium-49 and chlorine-38 which are all beta/gamma emitters15,16 (see appendix
A).
2.3.1.3 Contamination
If radioactive material becomes attached to an individual, in their clothes, skin, hair etc, they
are said to be contaminated. As long as the radionuclide remains on the outside of the body
(i.e. it is not absorbed through skin, wounds or orifices) the exposure remains classed as
external, but unlike irradiation, these situations pose a danger for emergency and medical
workers as the radionuclide stays on individual and can cause contamination of other people
and equipment, potentially leading to other individuals receiving both external and internal
exposures. Decontamination must be accomplished alongside any treatment for the dose
received.
2.3.2 Internal exposure routes
Internal exposures arise when radionuclides are incorporated into the body. Dose will
therefore continue to be received for as long as the radionuclides remain in the body, which
can potentially be for the rest of the person’s life. For dose record purposes, the committed
effective dose is used – the predicted dose integrated over the next 50 years from a given
intake is added to the person’s dose record for that year. Static internalised radionuclides
can give rise to a very high localised dose which is qualitatively different in its effect to an
external dose6.
As with external contamination, there is a risk that those treating the casualty and the
surroundings will become contaminated, although this is easier to control if the radionuclide
is entirely internalised. However, it is likely that a casualty with a radioactive intake may also
be externally contaminated11, and their body excretions may contain radioactive material.
There are several routes by which a radionuclide may enter the body:
2.3.2.1 Absorption through skin
Percutaneous absorption is of concern with all types of radionuclides17. However, passage
through the lower stratum-corneum layer is much less common17, with only a few
radionuclides, such as tritium, able to be absorbed through unbroken skin. Therefore for the
8
majority of radionuclides surface contamination remains external, although there remains
an inhalation/ ingestion hazard.
2.3.2.2 Entry through wound/ Injection
If the skin is broken, or the radionuclide is injected by some means through the skin, the
radionuclide will first occupy the subcutaneous tissue that lies immediately under the skin 18.
From here, it will be absorbed into the systemic circulation or regional lymph node17 and
eventually distributed around the body – uptake from this ‘transfer compartment’ to other
organs and the rate of excretion will depend on the exact radionuclide. The rate of
absorption into the blood will depend on the solubility of material, which in turn will depend
on its physical and chemical properties18.
2.3.2.3 Ingestion/ Inhalation
Because eating in designated areas is illegal under the ionising radiation regulations (1999)19,
the ingestion pathway is not common in industrial settings, although it is a pathway of note
for the general public following the release of radioactive materials to the environment.
One of the most common routes of occupational intake however is via inhalation. The ICRP
human respiratory tract model20 (HRTM) assumes that where the intake will be deposited
depends on aerosol particle diameter. The largest particles will be caught in the extrathoracic region (ET1: the nose and mouth) and then cleared to outside the body by coughing
and sneezing, but smaller particles will reach increasingly far into the respiratory system.
From here, it is assumed that the material will be cleared to 3 places; the gastrointestinal
(GI) tract via mucus action, the lymph nodes (from where it will clear to the blood), or
directly into the pulmonary and then systemic circulation. The rate of clearance to the GI
tract and lymph nodes is assumed to be independent of material20, but the absorption into
the circulation will depend on the solubility of the material; the more soluble it is the faster
it will clear20. The ICRP defines three default levels of solubility for when this is not
specifically known; fast (F), medium (M) and slow (S). These reflect rate of uptake from the
lung, expressed as approximate half-times for one or two components of clearance. What
happens following uptake into the blood will depend on the radionuclide and its chemical
form.
9
2.3.2.4 After metabolic uptake
The natural death of cells means that radionuclides incorporated into body tissues will
periodically be released back into the systemic circulation. From here, it may be re-absorbed
back into the same organ, absorbed by a new tissue type, or excreted from the body.
Figure 1: Summary of the main routes of intake, transfer and excretion (From Figure 1, ICRP78, 1997)13
2.3.3 Internal biokinetics of some radionuclides of interest
2.3.3.1 Uranium
Because uranium is an effective nephrotoxic agent, producing severe kidney damage in large
quantities45, and the two main isotopes of uranium have specific activities separated by two
orders of magnitude, the principle hazard from an intake of uranium can be chemical or
radiological depending on the isotopic make-up. In uranium compounds enriched to less
than 8%
235U
by weight, the specific activity is low enough to mean the chemical toxicity is
the limiting factor for intake17. Above 8%, the radiation hazard predominates; uranium is an
alpha, beta and gamma emitter and once in the blood it will be integrated into many tissues,
especially the kidneys and bones, giving a committed dose. The critical organ for less soluble,
enriched, compounds of uranium is likely to be the bone, or when inhaled, the lung 17. All
three solubility classes are found within uranium compounds.
10
2.3.3.2 Plutonium
All plutonium isotopes are alpha and low energy, weak gamma emitters – therefore pure
plutonium does not pose an external hazard but can give a large internal dose due to the
alpha radiation11. However, plutonium suffers from in-growth of americium-241 (a betadecay product of 241Pu) which is a gamma emitter and so older samples can pose an external
hazard. Plutonium is generally very poorly absorbed from the gastrointestinal tract, although
it will irradiate the gut as it passes through. If inhaled, plutonium will stay in the lung and will
slowly be absorbed into the circulation, at a rate depending on solubility of the particular
chemical form11. Some plutonium forms (nitrates, chloride, and metallic) are moderately
soluble (type M), others (such as the oxides) are type S. Type S plutonium compounds in
particular will stay in the lungs for many years, meaning there could be high lung doses.
Once in the blood, plutonium will be particularly absorbed by the bones and liver.
In the body plutonium is excreted very slowly and will remain in the body for the rest of the
person’s life – plutonium-239 has a radiological half life of 24,000 years. Plutonium-238 has a
half life of 86 years, so is 280 times more active per unit mass than
239Pu17.
Otherwise it
behaves in a similar manner.
2.3.3.3 Americium
Americium behaves very similarly to plutonium. It is also an alpha and gamma emitter and
shows minimal absorption from the digestive tract (only 0.03%17), although significant
respiratory absorption11. Generally the trans-plutonic elements are more soluble than
plutonium. Depending on the chemical form, trials in rats have shown an uptake from a
wound site of between 10% and 58% in the first 24 hours21. Once in the blood the primary
toxicity comes from liver (45-70% of intake deposited here17) and skeleton (10-45%)
deposition where it can cause bone marrow suppression. Both common isotopes (241Am and
243Am)
have an effective half life in the body of 100 years – this is 140 to 195 years for bone
and 40 years for liver17.
11
2.4 Objectives of Medical Treatment
Chapter 2 has described the current scientific understanding of how ionizing radiation
interacts with the human body and the important fact that exposure to ionising radiation
can result in detrimental health effects.
Armed with information about the pathways by which the body may receive a dose of
radiation, a sequence of objectives for the medical treatment for those who have been in a
radiation accident can be created. These have the main goal of reducing the acute and long
term clinical effects of radiation exposure as much as possible, achieved by reduction of
dose and treatment of biological damage sustained. All these objectives need to be met
while also treating conventional (non-radiation induced) injuries.
1. Removal of radioactive material from initial deposition site (both external and
internal) to prevent uptake to systemic circulation and further contamination.
2. Prevent uptake to systemic circulation, such as treatment to reduce absorption from
the gastrointestinal tract.
3. Removal of as much radioactive material as possible from systemic circulation before
it becomes incorporated into body tissues by increasing excretion and elimination
from the body, and/or reducing deposition rates to tissues.
4. Continued treatment to ensure any incorporated radionuclides are removed as
quickly as possible by maximising rate of excretion/ elimination.
5. Treatment for any short term health effects resulting from the dose (e.g. ARS)
6. Treatment for any medium to long term health effects resulting from the dose
Some of these objectives will not be necessary depending on the exact nature of the
radiation accident. For example, treatment for irradiation without contamination will not
require objectives 1 to 4.
Chapter 3 examines the medical treatments currently available to meet these objectives.
12
3 Literature Review of Recommended Medical
Treatments
Many books and articles have been written on the topic of dealing with radiation accident
victims. Generally, there is a consensus across all such texts about the processes that should
be conducted, the order in which they should be carried out, and the exact treatments that
should be used, although the finer detail naturally varies between authors. What follows is a
summary of this literature and the advice given.
3.1 General procedures to deal with an accident victim with
combined injuries
3.1.1 Immediate procedures at accident location
According to Mettler et al.12, radiation accidents generally involve mixed injuries; irradiation
and/or contamination alongside burns, heat stress, cuts and skin damage, chemical effects
and possibly serious trauma.
All of the relevant literature reviewed for this project is agreed that decontamination,
radionuclide decorporation (removal from systemic circulation) and treatment for radiation
induced injuries should take place after initial treatment of life threatening trauma and
physical injuries11. The first priority should always be to stabilise the patient 11. The following
list, which combines the advice from several key references11,12,17,22, describes a generic
process to deal with a casualty from a radiation accident. One or more or the stages may not
be appropriate depending on the nature of the accident and the effects on the casualty, and
the stages are not necessarily in the order in which they may be carried out – many may be
done simultaneously.

If in immediate life threatening danger or high dose rate area, move casualty away
from accident location. Otherwise stay there until stabilised.

Check casualty’s airway, breathing and circulation. Provide emergency/life saving
care and stabilise. Prevent bleeding and infection. Dispatch to hospital, if required.

Remove patient from contaminated/ radiation area to a decontamination area.

Survey for surface contamination. Try to identify isotope(s) involved in the accident.
13

Take swabs; 2 nasal (one from each nostril), and throat. Counting the activity on
these will help with accessing intake, but swabs must be taken soon after the event
and before any decontamination is carried out or the body’s natural clearing
mechanisms will greatly reduce the amount of material in these areas.

Remove clothing and decontaminate as much as possible at this stage (see section
3.2). Cover wounds before and after decontamination efforts to avoid intake. Save all
swabs from decontamination for later analysis.

Re-monitor, paying special attention to body parts that were originally exposed. Use
specialist wound monitoring equipment on any suspected contaminated wounds.

Transfer casualty to a medical facility for further treatment depending on injuries/
intake (see sections 3.2.1 to 3.6 below). Take care to keep ambulance and facility as
free of contamination as possible.

Send personal dosimeters for processing.

Start collecting all urine and faecal samples to get information on size of intake.

Begin monitoring blood pressure/gases/electrolytes and take blood samples for later
counting and blood grouping whilst blood count is still at approximately normal
levels.

Do a full blood count and white cell differential count every 4 hours. Send samples
off for biodosimetry (e.g. dicentrics counting, FISH23 or 24Na spectroscopy for neutron
dose14).

Manage the accident scene; build up a history and profile of the accident including
where people were and the routes they took to leave the building.
3.1.2 Treatment decisions
Exact information about the accident and doses received may be sparse in the first few
hours/days following an accident, but a decision whether to begin treatment may be
necessary, as many treatments rapidly become less effective with increased time since the
accident. Menetrier et al.24 noted “it is recognised that different organisations will have
different strategies in place [concerning decisions to treat intakes]. In broad terms, there are
two different approaches: urgent and precautionary.” An urgent strategy will treat even
when an intake is only suspected, and treatment will be revised later when more
14
information is available. This strategy maximises the effectiveness of the treatment, but can
put the patient at unnecessary risk and makes dose assessment more complicated. A
precautionary approach negates these disadvantages, but may mean required treatment is
begun too late to have maximum benefit24.
According to many authors’ opinions17,24, it is acceptable to make initial treatment decisions
based on only limited dose and intake estimates, although early monitoring should hopefully
give a approximate idea of scale and isotopic make-up17.
Wood et al.25 argue that “decision levels should be set on the basis of risk, which is a function
of the committed effective dose”, rather than based on the current legal dose limits. They
argue a balance should be drawn between the dose reduction a given treatment provides
and the risks from that treatment. Although this balance will vary from case to case,
generally, if intake size and composition is reasonably well known, the following decision
thresholds are recommended22,25;
Table 3-1: Treatment decision thresholds based on intake (in terms of annual limits of intake (ALI) – the size
of intake that gives a CED equal to the annual dose limit) and committed effective dose (CED – the dose
received over 50 years due to the intake)
Intake Size Committed Effective Dose Recommended Action
(ALI)
(mSv)
<1
<20mSv
No treatment necessary unless risks are minimal.
1-10
20 – 200
Decision to treat subject to medical judgement.
Potential efficacy and benefits should be
compared to risks of treatment
>10
>200
Treatment should be seriously considered; risks
from treatment would have to be very large to
decide against treatment.
The only caveat to these decision levels mentioned by Wood et al. is for bronchopulmonary
lavage (BPL), now known as whole lung lavage (WLL), which they argue should only be used
to prevent deterministic effects and so not be contemplated below 5 sieverts (Sv) lung dose.
This approach has been criticised because the sievert only applies to stochastic effects; the
gray-equivalent should be used instead (see section 2.2.1)43. Additionally their argument
appears flawed as they claim that a 1 in 50,000 risk of serious complications from WLL
makes it justified only for a 5Sv [sic] dose, but they recommend intravenous injections, for
which they state a higher risk of 1 in 20,000, for doses of only 200mSv; 25 times less.
The general consensus is valid however; any treatment must have a net benefit and the
decision levels in Table 3-1 are a useful quick guide to making sure this condition is met.
15
3.2 Dealing with external contamination
The aims of external decontamination are threefold; to prevent radiation injury to the skin
and deeper tissues, to remove the possibility of further internal uptake and to stop the
spread of contamination to reduce the risk to other people26.
The TMT handbook22 advises the following procedures for dealing with externally
contaminated persons, which is in broad agreement with other literature. Note that no
clinical studies to assess the benefits of one method of decontamination over another
appear to have been completed. The procedures, techniques and chemicals recommended
generally appear to come from common sense, educated guesses or past experience, but are
at least broadly supported by current scientific knowledge.

All staff to wear personal and respiratory protective equipment (PPE and RPE).

Wash contamination from breathing zone and give casualty RPE while clothing is
removed.

Remove clothing and place into a plastic bag which is removed immediately to secure
storage17.

Monitor skin and record type and extent of contamination.

Wash skin: the general advice for clearing radioactive contamination off unbroken
skin is to follow a hierarchy of solutions which get more aggressive going down the
list. Every author and organisation have their own particular list of cleaning methods
and there are many suggestions in the open literature, but an example generic
hierarchy, coalesced from several sources, is given in Table 3-2 below. All follow the
basic premise of being as gentle as possible, as skin irritation can increase
absorption17, so the skin is not irritated by the decontamination efforts.

Decontamination should stop when skin integrity is being compromised, when no
more than 10% of the remaining contamination is being removed each swipe, or
when remaining contamination is less than 2 times background.

Decontaminate with a single sweeps from the outside of the contaminated area into
the middle27.

Change gloves frequently and monitor hands to prevent spread of contamination.

Rinse eyes, nose and ears with water or saline.

Clip nails and shampoo hair if relevant.
16
The TMT Handbook also recommends brushing teeth, rinsing the mouth with 3% citric acid
and gargling with 3% hydrogen peroxide solution to clear larynx. This advice is not repeated
elsewhere and, as well as having no scientific basis for assuming these solutions will be at all
effective in decontaminating the area, would seem to contradict the fundamental principle
of avoiding actions that will irritate the flesh and thus lead to a higher uptake to the blood.
Therefore, it is judged that this particular advice is not consistent with best practice.
Table 3-2: Hierarchy of solutions for decontamination of skin, as suggested by the TMT Handbook22
Non specific solutions (to be tried in order)
Water or saline
Common soap and water
Mild detergent solution (pH≈5)
Mildly abrasive soap or cornmeal mixed with
washing powder
Antiphlogistic topical ointment (especially for
fingers)
3% hydrogen peroxide solution
1% sodium hypochlorite solution (not facial)
[shown to be effective by Lagerquist et
al.28]
5% Potassium permanganate aqueous solution
(not on sensitive areas), followed by 5%
sodium hyposulphite and rinse
Radionuclide Specific Solutions
Uranium
Isotonic 1.4% bicarbonate solution
Plutonium/Americium
10% EDTA aqueous solution or
1% CaDTPA in aqueous acid (pH≈4) solution
(See section 3.5.1 for
information on chelating
agents.)
3.2.1 Decontamination of burns
Chemical or thermal burns that are contaminated should be washed with saline 17, but
nothing more. In past cases28 this initial washing has had little effect on the amount of
contamination, but it was found that the eschars over the burns contained more than 99.9%
of the contamination, which was therefore naturally removed when these fell off. In the
mean time, the contamination was immobilized from entering the systemic circulation in the
eschar.
3.3 Treatment of Irradiation Injuries
3.3.1 Whole Body (Acute Radiation Syndrome)
Categorising an exposure accident as a whole body exposure can be difficult if judged purely
on the extent of the radiation field. For this reason, those accidents in which the trunk of the
body receives sufficient dose to cause systemic symptoms (i.e. acute radiation syndrome)
are often classed as whole body exposures. Partial irradiation of the torso causes similar
17
symptoms to whole body exposure, but normally with quicker recovery times and a higher
LD50 (the dose which is lethal for 50% of the population)12.
If prodromal symptoms of acute radiation syndrome (ARS) appear following exposure, or if a
large over-exposure is suspected, it is important to record early symptoms, signs and body
measurements in order to predict the likely severity of the later stages of the syndrome 12.
For the prodromal stages of ARS, the recommended course of action is to just offer
symptomatic treatments27; e.g. prochlorperazine to reduce nausea and vomiting. Because
the prodromal stage is then followed by a latent stage of relative well being, it is
recommended than any operations vital for preservation of life due to ‘conventional’ injuries
be performed within the first three days following exposure or they must be left until after
recovery.
Crosbie and Gittus27 recommend that anyone with a dose of greater than 1Gy is hospitalised
in preparation for Hemopoietic (bone marrow death) syndrome or worse. To aid recovery
from this, the patient will require a completely sterile environment; every effort should be
made to prevent infection from inhaled or ingested materials. This may mean air filtration
systems, sterilisation of all food (none uncooked), scrupulous use of sterile techniques,
barrier nursing techniques, and antibiotics and antivirals being prescribed12. Additionally, it
may be necessary to completely sterilise the gut if leukocyte and lymphocyte counts reach
dangerously low levels, and give blood transfusions to help maintain erythrocyte and
platelet populations.
Should the whole body dose received be great enough to permanently kill the bone marrow
stem cell population, and efforts made to facilitate the regrowth of their own bone marrow
fail, the casualty’s only chance of survival will be a bone marrow transplant. Good
circumstances (young patient, no complications and a closely matched donor) can mean a
success rate as high as 70% for such treatment12.
Note that at even higher doses (>10Gy, which is sufficient to kill the gastrointestinal stem
cells), there is currently no available treatment. It is hoped in the future stem cell research
may offer novel treatments for such injuries, but these are currently several years away.
3.3.2 Localised Radiation Injuries
Generally, when a small area of the body receives a very high dose, and the rest of the body
received a relatively low dose, these are classified as local radiation injuries 12. Because
18
penetrating torso doses are treated as whole body doses (see above), local radiation injuries
are normally associated with high doses to the skin, extremities, gonads or eyes.
Treatment of skin injuries is normally symptomatic with maintenance of cleanliness and
prevention of infection. While not usually fatal in themselves, skin injuries can be a focus for
infections in immunosuppressed patients. Most skin injuries will heal spontaneously within 6
to 8 weeks, although severe lesions such as necrosis will probably have to be treated with
skin grafts12. In the worst cases, amputation may be required to save infection of healthy
tissue.
3.3.3 Radioprotectors
A group of drugs known as radioprotectors are known to reduce the effects of ionising
radiation on living cells1. Their effects can be divided into two categories; cytoprotection,
which stops indirect damage to DNA by free radicals (which accounts for 75% of the total
DNA damage); and antimutagenic, which helps ensure high fidelity DNA repair meaning no
mutations are transferred to progeny. The most promising radioprotector drug discovered to
date is WR-2721 (amifostine), which has large dose reduction factor – 2.7 for bone marrow
killing – good antimutagenic properties and relatively low toxicity1. Amifostine is licensed by
the United States Federal Drug Agency (USFDA) for clinical use during radiotherapy to help
protect healthy tissue.
Unfortunately, because the free radicals created by ionising radiation damage DNA within
1ms of their creation, the cytoprotector drug must be present in the cell before irradiation
to prevent DNA damage occurring29. This means protection against deterministic effects can
only be achieved if the radioprotector drug is administered (ideally about 30 minutes) before
an exposure, meaning such drugs are useless for preventing deterministic effects after an
accident. The level of amifostine required to obtain a protection factor of 2 also produces
some debilitating side effects such as vomiting and hypotension, contraindicating its use for
emergency responders although lower doses may be of some use.
However, there is evidence30 that a much lower dose of amifostine administered up to three
hours after exposure can still offer a large antimutagenic effect. Oral delivery of the drug in
such cases has also been shown to be viable31. Treatment of casualties with amifostine may
therefore reduce the likelihood of long term stochastic effects, the equivalent of reducing
the effective dose.
19
A review paper from Los Alamos National Laboratory32 also suggests that a range of standard
nutritional supplements, such as vitamins (A, C and E) and minerals (Cu, Fe, Mn, Zn) have
considerable radioprotective properties. Therefore, there is an argument for giving all those
who may be exposed to radiation such supplements as a preventative measure.
3.4 Dealing with radioactive material in wounds
Wounds can become contaminated when loose material gets into an already open wound or
when radioactive material is left in a wound which it creates (e.g. a cut made by a sharp
piece of radioactive metal).
The Handbook of Nuclear, Biological and Chemical Agent Exposure11 recommends initially
using sterile saline to irrigate wounds. If the wound is known to contain plutonium or
transplutonic elements, diethylene-triamine-pentaacetate (DTPA) solution should be used to
irrigate the wound11 as it will chelate any soluble metal ions (see section 3.5.1). Even if the
chelate complex was then to enter the blood stream, it would stay complexed and be quickly
excreted, so this is preferable to uptake of the pure substance. This method has proved
effective in the past, for example Lloyd et al.21 found Zn-DTPA prevented almost complete
translocation from a wound site into body organs. Note that DTPA will not be any more
efficient than saline at removing insoluble plutonium or americium from a wound 17.
Irrigation with sodium bicarbonate will serve a similar enhanced excretion purpose for
soluble uranium.
If the amount of contamination in the wound remains high after simple irrigation, it may be
worth considering surgical excision of the wound12. The amount of dose that would need to
be averted in order to justify this option will depend on the location of the wound and the
risks of scarring and loss of function that would arise from such a procedure. There is also a
risk from anaesthesia (0.0005% death rate per procedure) if this is to be used. If excision is
to be carried out for soluble plutonium or americium, it is highly recommended17 that
intravenous chelation therapy is begun before the procedure so any material entering the
circulation during surgery is diverted to urine rather than taken up by bone or liver.
Excision can be highly effective at removing contamination; Schofield et al.33 managed to
remove 90% of the original deposition by excision in one documented case, with a further
4% being diverted by DTPA treatment, and Lloyd et al.21 removed close to 50% of
20
contamination from a puncture would by removing just a small slice of tissue around the
entry hole.
Any visible fragments in the wound should be removed if benefits outweigh the risks, and
treated as highly radioactive until proven otherwise. This means medical staff should not
handle them directly, but should use forceps and quickly transfer them to a shielded
container for future analysis and disposal12.
Amputation will likely be vigorously resisted by the patient and should only be used if the
limb will be lost anyway due to the trauma or local dose it has received, or the amount of
mobile contamination within it which cannot be removed in any other way is of life
threatening mangnitude17.
Finally, two authors17,26 mention the use of venous jamming to delay the spread of
contamination around the body from a wound. There appears to be no documented cases
where this technique has been used in radiation accidents, effectively or not.
3.5 Dealing with internalised contamination of specific radionuclides
3.5.1 Soluble Plutonium/ Americium
If a soluble form of plutonium and/or americium is inhaled, injected or gets into a wound,
some will be taken up into systemic circulation relatively quickly (e.g. for ICRP default type M
material deposited into the lungs, approximately 10% of the intake is absorbed to blood with
a half time of 10 minutes, the other 90% with a half time of approximately 140 days34). This
means that treatment should potentially address both the activity which has already been
absorbed into blood, plus the activity remaining at the site of initial deposition.
Treatment options for dealing with material remaining in a wound are discussed in section
3.4 above. For inhalation, the only method of clearing any material deposited in the lungs is
a lung lavage, as discussed in section 3.5.2 below.
For plutonium or americium which has already entered the circulation, it is necessary to get
the material into a form which will be removed from the blood by the kidneys and excreted
in urine. In the late 1950s, it was found that salts of DTPA were effective chelating agents for
plutonium and americium35, and remain the drugs of choice recommended by all the
literature today. DTPA chelates the plutonium ions into very stable complexes which are
then excreted by the kidneys. The alternative EDTA complex will also perform the same
21
function, but forms less stable complexes which are liable to break apart before excretion,
and therefore EDTA is not as effective as DTPA.
The recommended dose is 30μmol kg-1 day-1 for humans in the period immediately after
exposure, which is 1g of DTPA per day for a 70kg adult. It is almost universally recommended
that this is delivered as 1g in 250ml of saline or 5% dextrose or glucose solution
intravenously (IV) over 3 to 4 minutes24, or the drug can be mixed 1 to 1 with water, then
nebulised and inhaled36. The literature mentions both administration routes without obvious
preference except for large intakes where, because only about 10% of the drug reaches the
blood stream for nebuliser administration, IV administration is preferred. IV administration
does carry higher risks however, which is why aerosol intake is just as favoured for smaller or
only suspected intakes. There is also evidence from Stather et al.37 that aerosol
administration increases excretion of soluble plutonium deposited in the lung compared to
when the drug is injected by at least a factor of 2.
DTPA has been seen to enhance excretion of plutonium by 10 to 50 times over background
rates35,38, although this excretion rate exponentially decays during each treatment period
with a half life of 4 to 7 days33, presumably as all available plutonium in circulation is
excreted. Studies17,35,36 have found the overall effectiveness of DTPA therapy in removing an
intake to range between 10% and 99%, with one early study21 claiming a result of 100% of
liver deposits and 75% of skeleton deposits being avoided by DTPA treatment for a year.
Decision to treat using DTPA should be made as early as possible as effectiveness drops
rapidly over a few hours24.
DTPA appears to have few serious side effects (no serious toxicity in 1000 administrations36),
and low occurrence of minor side effects; only 12 people out of 485 recorded (2.5%)
experienced side effects when treated with DTPA39. These minor side effects included
vomiting, nausea, chills, fever and cramps but in all cases lasted less than 24 hours.
Animal experiments have shown DTPA chelates and removes biologically important trace
metal ions, which in theory could cause serious toxic side effects in humans24. Zinc excretion
was seen to rise to 5 times its normal rate during DTPA treatment by Schofield and Lynn 35
and loss of zinc can lead to kidney lesions, intestinal damage and interference with DNA
synthesis. However, use of Zn-DTPA, or a zinc supplement with Ca-DTPA can help reduce or
eliminate these effects40, and studies of patients involved in long term DTPA treatments
using supplements have shown no health problems24. Oak Ridge reported that in one patient
22
who was administered DTPA for 3 years, out of 24 trace metals monitored, only zinc was
more rapidly excreted than normal, and although an extra 18mg of zinc was lost per week,
the 132mg extra intake from the Zn-DTPA easily compensated the loss36.
Doctors Breitenstein, Fry and Lushbaugh39 state “DTPA is so free of side effects, and
information regarding [intakes] is so commonly incomplete that we would treat immediately
on suspicion of deposition and review once better dosimetry was available.”
That said, the potential harm caused to the kidney means that Ca-DTPA is contraindicated
for people with kidney problems – Zn-DTPA is recommended instead. DTPA is also
contraindicated for uranium and neptunium intakes as unstable complexes are formed
which can actually increase the overall biological damage compared to if no DTPA was
given36. There is little information in the literature about what ratio of plutonium to uranium
will contraindicate DTPA treatment, although an effort has been made in appendix B to
calculate this value based on the work of Muller et al.41. However, other research by Houpert
et al.42 found no increased toxicity when injecting both DTPA and uranium into rats
compared to just uranium and concluded this contraindication was unnecessary.
As an additional precaution against toxic effects, the zinc salt of DTPA is recommended for
long term treatments. However, all the literature states (although without any references to
experimental studies to back up the recommendation) that the calcium salt is 10 times more
effective in the first 24 hours after exposure, so recommend Ca-DTPA for the first 24 hours
and then Zn-DTPA for continuing treatment, as in the longer term they apparently (again,
without reference to any supporting studies) have equal effectiveness.
The most serious risk from DTPA therapy when used with plutonium would hence appear to
be the risk of air bubble embolism from the IV injection (Wood et al24. give this risk as 1 in
20,000 but this seems very high), but even this can be avoided if the drug is inhaled.
Although the drug is not fully licensed in most countries, including the USA, France and the
UK, this appears to be due to a lack of impetus from the drug companies as the drug has no
uses outside of radionuclide decorporation (removal from systemic circulation) therapy and
so little commercial prospect24 rather than because of regulator concerns. Anecdotal
evidence suggests that DTPA has been used recently at Sellafield in the UK and is currently
routinely administered, sometimes preventively, in nuclear facilities in France.
23
3.5.2 Insoluble Plutonium/ Americium
For insoluble plutonium and americium compounds, such as the high-fired oxides, DTPA
therapy has shown to be ineffective35. However, given these compounds are insoluble, the
uptake to blood will be much slower and so there will be less of the radionuclide entering
systemic circulation in the first few days after an accident anyway. Hence the focus should
be on clearing the deposited material from the body. Decontamination of wounds is
described in 3.4 above, and there are no special recommendations for these materials.
Due to the very low solubility, material deposited in the lung will generally stay there for
many years. This can lead to very large localised lung doses, causing deterministic effects
such as pulmonary fibrosis. Alternatively, particles deposited in the bronchioles will slowly
(over approximately 30-60 days) migrate to the regional lymph nodes before entering the
circulation as an insoluble particle, which can cause large doses to the lymphatic system and
other tissues. It is therefore desirable that any deposition is removed. The only treatment
available for this is whole lung lavage (WLL), which can be stressful and uncomfortable for
the patient and carries the risks of multiple general-anaesthetic operations (0.0005%
mortality rate per operation43), although the procedure is now much safer for healthy
patients than it once was. The lavage must be carried out between day 3 post exposure (by
which time the body’s mechanical clearance mechanisms will have removed what they can)
and day 30, after which the particles will be too deeply imbedded to be removed. Past
experience has shown the first lavage will remove approximately 25% of the deposited
material, with another 25% removed in another three to four procedures. More than 5
repeats carry no further benefit43.
As always, the dose reduction benefits of this procedure must be balanced against the risks.
Improvements in safety for this procedure mean that this operation is now definitely
recommended if the lung dose may lead to deterministic effects (greater than 6Gy-Eq) and
treatment for lower doses should be considered on a case by case basis43.
24
3.5.3 Uranium
As discussed in section 2.3.3.1 above, only enriched uranium presents a radiotoxicological
health risk compared to a nephro-toxicity risk. However, the chemical toxicity of the element
possibly makes it even more important that any intake is removed as quickly as possible.
Treatments for dealing with uranium activity at initial deposition sites, be it skin, wounds or
lungs remain the same as for other elements as described above, and given the chemical
toxicity of uranium, it is recommended11 that maximum effort be put into removing any
sizable contamination before it reaches systemic circulation. Therefore, surgical excision of
wounds or lung lavage (for insoluble forms) would certainly be recommended to avoid
intakes leading to more than 3μg uranium per kidney44, which equates to an inhalation of
60mg in a worst case scenario45, due to the chemical toxicity. In the case of highly enriched
uranium, the radiological risk becomes the limiting factor, in keeping with other guidance,
appropriate treatments to reduce dose should be considered for intakes of greater than 1
annual limit of intake (ALI).
In the event that it is suspected uranium has entered the circulation, sodium bicarbonate
should be administered – this reacts with the uranium to produce uranium bicarbonate
which is less nephrotoxic than uranium and is excreted by the kidneys. It is recommended
that the drug is delivered as an IV infusion of isotonic 1.4% sodium bicarbonate solution 11,
although when delivered intravenously sodium bicarbonate can disturb the body’s acid-base
balance and electrolytes concentrations. This means IV administration should only be
attempted where these can be effectively monitored. Oral administration of sodium
bicarbonate can be used for when IV administration is not possible.
The effectiveness of this treatment decreases extremely rapidly with time – most texts refer
almost zero effectiveness if not begun within the first 30 to 60 minutes after an intake 26.
Additionally, many books11,17 mention the use of renal dialysis to support the kidneys in the
extraction of uranium and to reduce the exposure of the kidneys to the uranium.
25
3.6 Summary of Treatments and Risks
Table 3-3: Summary of Treatments and Risks
All
Skin
Contamination
General
Treatment
Recommended
 Use hierarchy of
cleaning solutions,
starting with soap
and water. Care not
to damage skin
 Irrigation with saline
 Removal of visible
contamination
 Surgical Excision
Reported
Effectiveness
 Depends on
nature of
contamination up to 100%
 Irrigate with DTPA

40% of uptake
diverted
 Irrigate with sodium
bicarbonate
 Lung Lavage

50% of
deposited
activity removed

Lungs
Systemic
Circulation
Committed
Effective Dose
 Further irritation
of the skin can
increased risk of
absorption and
soreness
Depends on
wound – up to
100%
Wound Site
Soluble
Pu/Am
Soluble U
Side Effects/ Risks
 Loss of function –
risk varies
 Minor side
effects, 1 in 40
 Serious
complications
(coma, death)
from general
aesthetic, 1 in
200,000)
Soluble
 Ca- or Zn- DTPA
 Up to 99%
 Minor side
Pu/Am
effects, 1 in 40
 Possible toxicity
(never seen in
humans)
 If injected, risk of
air bubble
embolism and
infection
Soluble U
 Sodium Bicarbonate
 If injected, risk of
air bubble
embolism and
infection
Risk of deterministic effects: acute dose of over 500mSv required, ED50 varies
Risk of cancer and genetic effects: 4.2% Sv-1 for adult population5
Lifetime cancer risk from 1mSv dose: 1 in 25000
Lifetime cancer risk from 20mSv dose: 1 in 1250
Lifetime cancer risk from 500mSv dose: 1 in 50
Lifetime cancer risk from all causes:
1 in 3
All
Insoluble
Particulate
26
4 Dealing with casualties in radiation accidents at AWE
This chapter describes how the casualties from a radiation accident that occurs on an Atomic
Weapons Establishment (AWE) site would be managed and treated.
There are so many different variables for a radiation accident that it is impossible to cover
every eventuality here. Therefore three scenarios, designed to reflect the range of work
done at AWE, have been chosen to illustrate the procedures in place to deal with radiation
accidents. The radionuclides considered have been limited to plutonium (with possible
americium and/or neptunium content) and uranium as these are the radioactive materials
which are most commonly encountered and handled on site.
This chapter has been written based on company documentation46 and interviews with
members of the AWE health physics community, the AWE dosimetry service and staff from
Trident Medical Services (TMS), the company contracted to provide occupational health
services on AWE sites.
The first two scenarios assume a small number of casualties (one or two), so health physics
and medical staff can treat any injuries promptly. Scenario three is concerned with the
handling of a large number of simultaneous casualties.
27
4.1 Contaminated wound scenario
4.1.1 The Scenario
During normal working hours, a worker in a controlled area receives a puncture wound,
which is not clinically severe, while handling radioactive material. For a severe wound,
emergency medical treatment would take priority over all radioactivity concerns.
4.1.2 The Response
4.1.2.1 Local Response
The casualty will alert the nearest health physics surveyor, who notifies their supervisor. The
casualty is immediately removed from the controlled area, undergoing normal exit
procedures and monitoring unless the injury is severe enough to prevent movement or
requires immediate emergency treatment.
The closest first aider is called to make an assessment of the severity of the wound, but they
are not required to make an assessment of the radiological consequences. Assuming the
wound is relatively minor, so no emergency medical treatment is required, a health physics
surveyor monitors the wound site with an AP2 contamination probe as soon as possible. The
AP2 is a scintillator-based alpha contamination probe with a detection limit of approximately
0.4Bqcm-2. The item that caused the injury would also be monitored. The casualty, relevant
local workers and management would be questioned to try to gain as much detail as
possible about the accident, especially details about the type of material (isotope and
chemical form) that was being handled. The results of these interviews and the monitoring
are recorded on a HPR119 incident report form (see appendix C) which goes with the
casualty through the rest of the process detailed below.
Meanwhile, a Health Physicist (HP) or Radiation Protection Adviser (RPA) and a member of
facility staff (normally the casualty’s line manager) are summoned. Additionally, a health
physics casualty liaison officer (HPCLO); a friend of the casualty who can handle personal
matters for them, such as arranging children being picked up from school, may be
appointed. The health physics control room (HPCR) is informed of the accident and given the
reference number from the HPR119 form for tracking purposes. The HPCR will alert the
approved dosimetry service (ADS) that they have an incoming person for wound monitoring.
If it is suspected following initial investigations that the wound is contaminated, Trident
28
Medical Services (TMS) are notified immediately and may attend the scene or keep in
communication via phone.
4.1.2.2 Gross Decontamination
If there is surface contamination on the casualty, they will undergo basic decontamination in
the facility, such as change of overalls and washing with soap and water, before being sent
for wound monitoring. Contamination not removed in basic procedures in the facility will be
covered and may be left until the wound is treated, depending on relative urgency.
4.1.2.3 Wound Monitoring
The casualty is walked to the wound monitoring suite accompanied by their line manager.
The aim would be to have the casualty in wound monitoring around 30 minutes after the
accident.
The wound monitoring equipment doubles as part of the whole body (in vivo) monitoring
equipment and consists of a hyper-pure germanium (HPGe) detector which is pre-calibrated
for all the radioisotopes used at AWE. Standard procedure is to monitor for 5 minutes, with
an additional 10 minutes of counting if contamination is suspected from the initial
measurements. Uranium and americium isotopes are counted directly by the gamma
spectrometer; plutonium is measured via the gamma emission from the americium-241
which will be present. The exact ratio of
241Am
to various plutonium isotopes will vary but
the ‘fingerprint’ of the sample to which the casualty has been exposed can be retrieved from
records. 15 minutes of counting gives a minimum detectable activity (MDA) of between
0.05Bq and 0.1Bq of
241Am
depending on the depth of the activity. Assuming a worst-case-
scenario activity ratio between the americium and plutonium of 20, this could mean an MDA
of 2.0Bq of 239Pu. If 0.1Bq of 241Am entered into systemic circulation, it would correspond to
a 50 year committed effective dose (CED) of up to 40μSv 47, however 2Bq of 239Pu will give a
CED of up to 1mSv 47. The measured activity in becquerels is recorded on the HPR119 form.
4.1.2.4 Medical Treatment
Regardless of whether the wound monitoring gives a positive or negative result, the casualty
is escorted to a medical facility. For contamination control, they will not be allowed entry to
the medical facility without the HPR119 form completed by wound monitoring. For a noncontaminated wound, the wound is cleaned and covered.
29
A contaminated wound will usually be treated in the site decontamination facility. Only
medical staff are permitted to decontaminate a wound. The wound will first be irrigated
with saline solution or with DTPA for Pu/Am contamination or sodium bicarbonate for
uranium contamination. Visible contamination may be removed if this involves a minor
procedure. The wound will then be re-monitored, and from this measurement, along with
knowledge of the solubility of the materials involved and the nature of the wound, an
estimate of activity assumed to have already been incorporated into the body plus the
activity now remaining at the wound site will be made.
From this estimate, a decision about further treatment will be made. Generally, if the
remaining activity is less than 1 ALI, no further treatment will be recommended. Between 1
and 10 ALI, the risks and benefits will be balanced to decide whether to treat. For intakes
greater than 10 ALI, treatment is always recommended.
The medical officer, in consultation with the HP/RPA (or the Head of Corporate RPA in
severe cases) and the patient, will decide on the treatment. In considering decorporation
treatment, informed consent must be obtained from the patient after a full explanation of
potential benefits and risks. Priority is given to the patient’s wishes in order to prevent
anxiety or later psychological complications.
If the activity is still located around the wound site, simple excisions and/or removal of large
pieces of foreign material are performed by doctors at AWE. For more complex surgery the
casualty is sent to the Windsor Hand Clinic, which is on standby to receive patients from
AWE. At least one member of health physics will always travel with a contaminated casualty
for off-site treatment. After treatment is completed the patient will be sent back to the
wound monitoring suite to confirm that the wound has been sufficiently decontaminated.
If systemic uptake is suspected, the treatment will depend on the isotopic make-up of the
contamination. For contamination by soluble plutonium or americium, Ca-DTPA will be
recommended – TMS policy is to treat soluble intakes immediately and aggressively to
minimise organ uptake, which will generally mean treatment for intakes of greater than 1
ALI is recommended. TMS deliver DTPA to the patient using a nebuliser to avoid the risks
and stresses associated with injections for both staff and casualty, unless a large intake is
suspected when DTPA will be given intravenously. The dose given is as recommended by the
literature – 1g per day. TMS will check the isotopic composition of the contamination with
the RPA to make sure there are no significant concentrations of contraindicating isotopes
30
such as neptunium or uranium present. For soluble uranium contamination, oral sodium
bicarbonate would be recommended to the patient to help reduce organ uptake of the
radionuclide. (Intravenously administered sodium bicarbonate cannot be given at AWE
because of the need for rapid monitoring of the body’s acid-base balance and electrolytes
following such administration; this can only be done in hospital.) In the vast majority of
cases, the patient will be receiving these medical treatments within an hour of the accident.
4.1.2.5 Follow Up
As soon as possible after the accident, regardless of whether wound monitoring found
contamination or not, the casualty is asked to start collecting urine samples for follow up
dosimetry. This is requested on a HPR118 (see appendix C) form. If contamination had been
detected, a one day urine sample would be collected and results returned within a day or so.
Faecal samples are not initially requested as the activity in such samples following a wound
would be low, and urine samples are much easier to collect and process. If activity is
detected in the sample a full dose assessment using modelling software is completed by the
ADS. The number of samples requested will depend on the size of the intake, the treatments
given and the accuracy to which the dose estimate is required.
Depending on the outcome of the bioassay, it may be decided that longer term treatment is
advisable. In particular, Zn-DTPA may be prescribed for weeks to months following the
accident to help clear plutonium out of the body. The zinc salt is used for any DTPA
treatment given more than 24 hours after the accident, in line with current
recommendations. The decision to go ahead with long term treatment will rest with the
medical officer and the patient based on bioassay data.
31
Figure 2: Flow diagram for Contaminated Wound Scenario
32
4.2 Containment failure scenario leading to contamination of skin
and/or inhalation
4.2.1 The Scenario
Failure of a glovebox, pressurised suit or other containment results in radioactive material
being released into the operator environment leading to contamination of personnel and
possible inhalation by workers.
4.2.2 The Initial Response
If the worker using a glovebox suspects a glove failure has occurred, either by visually
identifying a fault or due to a pressure change in the glovebox, they will shout for help,
specifying “glove failure” and keep their hands in the gloves. Their designated colleague,
who always remains on standby while glovebox work is occurring, will put on their own
respirator and then fit a respirator to the person with the failed glove. The colleague turns
off both workers’ personal air samplers (PAS) as these should record the inhaled activity and
since the workers are now breathing through respirator filters they should not inhale any
further activity from the air. They then wait for health physics to arrive.
Meanwhile, the other workers in the area will immediately remove themselves from
glovebox work, replace glovebox port bungs and then exit the area without exit monitoring
or donning respirators. These workers will gather outside the room, placing warning chains
across the doors and activate the “Do Not Enter” lights. They will also phone the facility
control room and notify them of the situation – the facility control room will notify facility
health physics staff over the tannoy and, if required, further health physics assistance via the
HPCR.
In situations where the continuous air monitoring (CAM) alarms activate, indicating activity
in the air, all workers in the lab would follow the ‘other workers’ procedure described above.
If exit monitoring reveals contamination, the contaminated person would alert others but
remain stationary, while again the others in the lab evacuate and raise the alarm, again as
above.
It is normal practice for at least two health physics surveyors to attend such situations. One
surveyor will remain outside the area to monitor those who have evacuated; the other will
put on a respirator and enter the area to deal with those directly involved.
33
At the glovebox, the worker will be asked to slowly remove their arms from the gloves as the
surveyor monitors them for contamination; if none is found, a complete head-to-foot survey
is completed. If clean, the person may leave the area and join those who evacuated to
outside. If contaminated, the decontamination procedure detailed in section 4.2.3 is used.
All those involved will be asked to attend a designated area (normally the health physics
office) so facial swabs and nose blow samples can be taken, and PAS filters can be counted.
Since the counting of all these items is completed locally and 60 second counting periods are
used, the results are known quickly.
4.2.3 Decontamination of Personnel
Ideally, contamination should be removed within the controlled area where the accident
occurs to prevent the spread of contamination. The site decontamination facility will be used
if it is more suitable or if the contamination occurs in a location without decontamination
facilities. To move to a decontamination room, the contaminated area of the body should be
wrapped with plastic bags, secondary overalls or gloves to contain the contamination. If the
contamination is on the coveralls, these may be changed while standing in a plastic bag to
catch loose contamination before going to the decontamination room.
Decontamination is initially conducted by health physics staff using soap and water.
Minimally wet swabs should be used, and the swabs should be kept for subsequent
monitoring. The skin should be dried with swabs after each washing and monitored. The aim
is to reduce the contamination to below detectable levels on an AP2 probe.
If the contamination proves persistent, or is in a sensitive area, the RPA/HP is notified and
the contaminated person will be escorted by health physics staff and their line manager to
the site decontamination facility, where they will be treated by a member of Trident Medical
Services staff. TMS staff will first try using detergent (fairy liquid) and water, repeating three
times. If contamination persists, the nurse will change gloves and try using baby wipes to
remove the contamination. If this fails to work after 3 repeats, facial cleanser wipes, which
are very slightly abrasive, will be used. Facial cleanser pads, which are a step more abrasive,
would then be tried, and if these did not work then 10% bleach solution may be used on
non-sensitive skin regions. TMS staff will continue to use these methods until either health
physics confirm the skin is decontaminated, no more contamination is being removed or the
skin is becoming damaged. In these latter two cases, a dry dressing will be applied and
34
decontamination will be re-attempted the next day. If decontamination is believed to be
successful, the patient will be checked by a hand monitor before returning to work.
Contamination that causes a detector to display a full scale deflection (FSD) will be treated
as above, but extra precautions such as increased PPE and RPE may be used until the
magnitude of the contamination is known. Use of a dose-rate meter may be possible to
determine the level of contamination if all contamination probes show FSD.
4.2.4 Treatment of Suspected Inhalation
An inhalation will be assumed by the medical officer and RPA if any one of a PAS count, nose
blow or nasal swab are above a decision level.
At this point, the casualty will probably be taken to the whole body monitor for lung
monitoring, conducted using the same HPGe gamma ray spectrometer as used for wound
monitoring. This equipment can rapidly give an idea of the magnitude of the intake, which is
useful for future decision making. However, soluble compounds may have already been
absorbed into systemic circulation by this time and so will be detected at a reduced level in
the lungs.
Therefore, as with wounds, there is a problem with treating suspected inhalation intakes in
the short term because of the potential uncertainty in the size and composition of the
intake. By the time this information is firmly established by bioassay and accident
investigation, the window for the most effective treatment will probably have passed.
Therefore, if an intake is suspected TMS will normally recommend treatment begins and reassess this when more information is available. This is especially true for soluble material
intakes, as the treatments are most effective if administered shortly after intake and are
relatively risk free. The treatments and recommended action levels will be the same as those
described in section 4.1.2.4 for systemic uptake.
For inhalation of insoluble materials, chelation therapy would not be effective. The only
treatment option is lung lavage; however the additional risks and discomfort from this
procedure means that it would not be recommended unless the expected lung dose was
greater than approximately 6 Gray-equivalents. Fortunately, lung lavage does not need to be
performed immediately, and so any decision about the procedure can wait until full dose
information is available from bioassay results, in-vivo monitoring and other dose
assessments, which should take 2 or 3 days to complete.
35
4.2.5 Follow-up
After any immediate medical treatment has been administered, the casualty will be asked to
collect samples for bioassay, in order to get more detailed information about the dose. For
inhalations, 3 consecutive faecal samples and 3 consecutive urine samples will be requested.
The casualty would also be sent for another in-vivo lung monitoring in the monitoring suite.
Any decision regarding long term medical treatment will rest with the medical officer and
the patient based on bioassay and lung monitor data.
36
Figure 3: Flow diagram for inhalation scenario
37
4.3 Mass casualty scenario
4.3.1 The Scenario
All workers from a facility are evacuated following a criticality, large release of radioactivity
or another large accident. Some workers may have received large radiation doses, some may
be contaminated and some may have conventional injuries.
4.3.2 Evacuation Centres
All workers that are able to will evacuate the facility and muster in the designated
evacuation centre. The AWE Fire and Rescue Service will attend such an accident and enter
the affected facility (if safe to do so) to rescue anyone who was unable to evacuate. The
evacuation centres are split in two; an ‘active persons’ side for those coming directly from a
designated area and a ‘non active persons’ side for those coming from the non-designated
parts of the facility. On arrival at the evacuation centre, those entering the active side will sit
in chairs arranged in rows in front of monitoring lanes, and put on ori-nasal masks.
The first action in dealing with potential casualties will be a triage process, to make sure
those in need of urgent treatment are prioritised. AWE employs a triage system based on
that used by the military; casualties are placed into categories P1, P2 or P3 depending on the
severity of their injuries, and may also be labelled with a C or D suffix:
Table 4-1: Triage Casualty Priority Codes
P1
P2
P3
C suffix
D suffix
Casualty with most urgent injuries. Needs life-saving treatment immediately
Casualty needs treatment but can wait – should be treated within 6 hours
Casualty needs non-urgent treatment and so can be last to be seen
Indicates casualty is contaminated with radioactive material
Indicates casualty has received a radiation dose
P1 casualties require immediate transfer to hospital for emergency treatment, and this takes
priority over contamination concerns. Therefore P1C casualties will be wrapped in PVC
sheeting and removed straight to an ambulance. P2, P3 and uninjured people will remain in
the evacuation centre and be processed in a priority order.
If there has been a criticality, the next stage will be to monitor criticality lockets and site
passes (which have an indium foil attached) to identify those who have been heavily
irradiated. 400 counts per second (cps) from a criticality locket on a BP4 probe equates to a
1Gy dose – those above this threshold are put forward for immediate monitoring, and those
38
with readings of 40 to 400cps are given increased priority. The results from the criticality
monitoring are put onto a HPR160 incident form (see appendix C) which each evacuee
carries throughout the following process and is completed after each monitoring procedure.
Those evacuees who remain in the seats are then monitored for gross contamination with
AP2 alpha probes and BP4 beta probes. Those who are grossly contaminated are segregated
into a separate lane to avoid spread of contamination and irradiation of other evacuees. The
decision level for who counts as grossly contaminated will depend on the number of people
who are contaminated to any level – the more people there are, the higher the level will be
set to make sure the most heavily contaminated are dealt with first. Contamination on the
head is given higher priority than elsewhere on the body.
Irradiated casualties
Those who have been flagged as irradiated following a criticality will be among the first
4.3.3
through the monitoring lanes; for details of procedures at this stage, see section 4.3.5. Once
cleared through monitoring, they will be taken into a separate room in the back of the
evacuation centre to await transport to the medical centre, which is conducted in priority
order. While waiting, they will be kept under observation and reassured by a first aider, and
interviewed to get information on the accident and their location when it happened. The
dosimetry (TLDs and criticality lockets) from this group will be priority dispatched to the ADS
for measurement; preliminary results can be available in around an hour.
Casualties will be transferred to the AWE medical centre, and admitted via the rear door.
Before being allowed in, an emergency patient record sheet will be established for each
casualty with their name and NI number. The casualties will then be placed in the ward area.
Based on knowledge of the casualty’s location at the time of the accident and their escape
route, along with measurements from their dosimetry items, a dose estimate is produced. If
it was thought that the victim had received a dose greater than a few hundred mSv, meaning
deterministic effects are possible, the medical staff on site will conduct a complete blood
count in order to establish the absolute lymphocyte count to help with later dose estimates,
and will also take swabs from all body orifices to build up information on likely infections if
the patient’s immune system is compromised.
Once appropriate information is gathered, a casualty with a large dose will be referred to an
NHS hospital for barrier nursing and any necessary treatment. Once the casualty has left site,
39
AWE medical staff have no further involvement in treatment. However, an AWE health
physicist or RPA will travel to hospital with the patient to advise and assist the hospital on
radiological protection issues. This is particularly important if contaminated casualties are
transported to the hospital.
AWE has a contract with the Royal Marsden Hospital for them to supply general support and
staff to site in the event of a serious irradiation accident.
4.3.4 Grossly contaminated casualties
Basic decontamination, such as removal of contaminated overalls and basic washing of skin
with baby wipes can be performed in the evacuation centres. More substantial
contamination, particularly on skin, will need to be removed in one of the decontamination
suites either in a facility or the general site unit. While awaiting transport to one of these
units the casualty will be prepared by wrapping the contaminated area to avoid spread of
contamination en-route. This can involve putting on a glove for hand contamination or
putting on a second pair of overalls or wrapping in PVC for contamination elsewhere on the
body. Once then casualty reaches a decontamination unit, they are dealt with as detailed in
section 4.2.3.
4.3.5 General monitoring of evacuees
One at a time, the evacuees will be called forward into a monitoring lane. Here, two
surveyors will carefully monitor each person for alpha, beta and gamma contamination with
the relevant probes. Any gross contamination that was missed earlier will be directed to the
segregated area as described above; small patches of contamination can be covered and
dealt with later once higher priority cases have been seen. Each PAS filter will also be
monitored by probe at this point to identify any in need of urgent counting - these will be
bagged and sent to ADS.
Once monitored, the evacuee enters the ‘clean’ side of the evacuation centre and puts on
new overshoes. They then approach the record keeping table, where their site pass and
criticality locket are rechecked, their dosimetry collected, a facial smear is taken and
counted for 30 seconds and nasal smears and the PAS filter are taken for later counting. All
of these results are recorded onto the HRP160 form, which is then split into several carbon
copies for the later attention of health physics, medical and the ADS.
Evacuees are then allowed into the non-active side for debriefing and release.
40
41
Figure 4: Flow diagram for mass casualty scenario
42
5 Conclusion
After a review of the available literature that deals with the medical treatment of casualties
following a radiation accident, it is clear that there is a consensus on the best techniques to
be employed. In some cases, this best practice is based on solid scientific research but for
many treatments the evidence for their suitability comes only from perceived common
sense and their successful use in the past rather than any thorough clinical trials. From a
scientific viewpoint, it would be good to see more comparative studies between different
treatments involving human subjects, but the ethics of such studies will probably mean that
evidence for the effectiveness of radiological treatments remains based on animal studies
and real accident reports.
The aim of this report was to compare AWE’s plans for the handling and treatment of
casualties following a radiation accident on site with industry best practice. The general
consensus of the literature review in section 3 has been taken to be this best practice.
Displaying these findings against AWE’s plans, as seen in Table 5-1, it is clear that AWE is
entirely consistent with industry best practice. For the majority of situations, AWE’s plans
match the recommendations exactly.
The only area where there is notable deviation is in the treatment of skin contamination,
where different cleaning substances are used to those recommended. However, this area
has been carefully considered by AWE and TMS staff and it has been judged that AWE’s
preferred cleaning methods are superior to those recommended in the literature when
cleaning effectiveness, damage to skin and psychological impact on patient are all
considered. Moreover, the level of contamination at which a patient is considered clean is
lower at AWE (no contamination should be detectable) compared to the recommendations
(contamination should be no more than twice the radiation background level). Thus it can be
considered that AWE is ahead of industry best practice in this area. Likewise, recent work on
whole lung lavage43, completed in part at AWE, provides new recommendations for the
industry based on the latest scientific findings.
There are several recommendations that have arisen from this review. Firstly, it is clear that
the weight of evidence from many relevant scientific papers is to support the view already
held by Trident Medical Services, if not all of the health physics staff at AWE, that DTPA is
safe, free of serious side effects if administered properly, and effective for the decorporation
43
of soluble plutonium and americium from systemic circulation. It is therefore recommended
that DTPA should be administered by nebuliser as soon as possible on any evidence of
plutonium intake exceeding 1ALI. The myth that DTPA is prohibitively toxic appears to have
no scientific founding and there is plenty of evidence to suggest that DTPA can be
administered safely even for extended periods. It could even be argued that the decision
level for DTPA treatment be lowered below the current 20mSv dose.
Secondly, the next few years should be an interesting time for the development, research
and licensing of several new drugs applicable to the treatment of radiation casualties.
Research for this project suggested that amifostine or a similar drug may prove itself in the
near future to display effective antimutagenic properties even when administered after
irradiation and hence have the apparent effect of reducing the committed effective dose.
There is also evidence that novel treatments such as progenitor cells48 will prove able to
support critical stem cell populations after irradiation and so raise the onset levels of acute
radiation syndromes. While none of these drugs can be recommended for use on human
patients at this time, AWE and TMS should keep a close eye on the development of such
pharmaceuticals to see if some should be stocked for administration on-site in the future.
Thirdly, it may be worth AWE considering issuing advice to its radiation workers on types of
foods and food supplements which have been found to offer radioprotector effects by
research such as the Los Alamos paper32.
Finally, a study should be conducted to assess the dose which may be received by those
dealing with neutron-irradiated persons following a criticality due to their activation. Initial
calculations for this project show that the effect may be higher than previously thought.
Overall it must be concluded that, at present, AWE is well prepared to meet the needs of any
radiation casualties and is as capable of dealing with such casualties as any similar
organisation. However, more research is required in the wider scientific and nuclear industry
communities to both gain more information about the effectiveness of current treatments
and develop new treatments that are more efficient and act with fewer side effects.
At AWE, it is important that procedures are kept under constant review so that any new
developments are incorporated into company capability as soon as possible, and that staff
continue to receive support for research and development of new techniques, procedures
and treatments. This will ensure that AWE continues to not just follow but to lead industry
best practice.
44
Table 5-1: Comparison of industry best practice and current AWE treatment plans
All
Skin
Contamination
General
Wound Site
Lungs
Soluble
Pu/Am
Soluble U
“Industry Best
Practice” – as
recommended by the
literature
How current AWE treatment compares

Use hierarchy of
cleaning solutions,
starting with soap
and water.

Care not to damage
skin

Stop when
contamination is
less than 2 times
background


Saline Irrigation
Removal of visible
contamination
Surgical Excision
Irrigate with DTPA
 AWE treatment is in keeping with the
general principle of using a hierarchy of
cleaning methods which get gradually
more aggressive. However, some of the
hierarchy stages are particular to AWE
although comparable with
recommended techniques.
 Most abrasive/ aggressive AWE
treatment is less severe than suggested
to avoid skin irritation. Experience
suggests no benefit from using
potassium permanganate etc.
 AWE will stop treatment if the skin is
becoming irritated or when
contamination is below detectable levels
on industry standard measurement
probes – better than best practice.
 As best practice – Windsor Hand Clinic
available for excision surgery.



All
Insoluble
Particulate

Soluble
Pu/Am


Systemic
Circulation

Soluble U
External Irradiation




Irrigate with
sodium bicarbonate
Lung Lavage if
danger of
deterministic
effects (e.g. lung
fibrosis)
Ca- or Zn- DTPA.
See text for dosage.
IV or nebulised
administration
Administer if intake
greater than 1ALI
Sodium Bicarbonate
IV or oral
administration
Hospital treatment
for deterministic
effects
Early blood tests
45
 As best practice.
 As best practice.
 As best practice – WLL will be
recommended above 6Gy-Eq lung dose
and agreements in place with Royal
Brompton Hospital to perform
operation.
 As best practice.
 Prefer to nebulise but both options
available as per best practice.
 TMS will recommend DTPA treatment at
low intakes, as per best practice.
 As best practice.
 Oral administration only as hospital
capability required for IV administration.
 Will dispatch to hospital for doses
greater than 1 Gy as per best practice.
 Initial blood counts and swabs
completed at AWE as per best practice.
Glossary of Abbreviations and Acronyms
ADS
ALARP
ALI
ARS
AWE
AWE(A)
AWE(B)
BPL
CAM
CED
CPS
DTPA
FSD
HP
HPCR
HPGe
HPS
IAEA
ICRP
ICRU
LET
MDA
NCRP
NDA
NI
PAS
PPE
PVC
RBE
RPA
RPE
TLD
TMS
UNSCEAR
USFDA
WLL
Approved Dosimetry Service
As Low As Reasonably Practicable
Annual Limit of Intake (Intake of activity that would give 20mSv CED)
Acute Radiation Syndrome
Atomic Weapons Establishment
Aldermaston Site of the Atomic Weapons Establishment
Burghfield Site of the Atomic Weapons Establishment
Bronchopulmonary (Lung) Lavage
Continuous Air Monitor
Committed Effective Dose (Dose from an exposure integrated over 50
years)
Counts Per Second
Diethylene-triamine-penta-acetate
Full Scale Deflection
Health Physics (or Physicist)
Health Physics Control Room
Hyper Pure germanium
Health Physics Supervisor
International Atomic Energy Agency
International Commission on Radiological Protection
International Commission on Radiological Units and Measurements
Linear Energy Transfer
Minimum Detectable Activity
National Council on Radiation Protection and Measurement
No Detectable Activity
National Insurance
Personal Air Sampler
Personal Protective Equipment
Polyvinylchloride
Relative Biological Effectiveness
Radiation Protection Advisor
Respiratory Protective Equipment
Thermo-Luminescent Dosimeter
Trident Medical Services
United Nations Scientific Committee on the Effects of Atomic Radiation
United States Federal Drug Agency
Whole Lung Lavage
, 49, 50, 51, ,
46
References
1
2
Dictionary of Science and Technology, Larousse, (1995)
The Health and Safety Executive, A guide to the Radiation (Emergency Preparedness and Public
Information) Regulations 2001, HSE Books, (2002)
3 HALL, E. J., Radiobiology for the Radiologist, 6th edition, Lippincott Williams and Wilkins, (2006)
4 ALPEN, E. L., Radiation Biophysics, 2nd edition, Academic Press, 1998
5 Annals of the ICRP, Publication 103, The 2007 Recommendations of the ICRP, Elsevier, (2007)
6 GREENING, J. R., Fundamentals of Radiation Dosimetry, Adam Hilger Ltd, Bristol, (1981)
7 WAMBERSIE, A., HENDRY, J., ANDREO, P., DELUCA, P., GAHBAUER, R., MENZEL G. and WHITMORE,
G., The RBE issues in ion-beam therapy: conclusions of a joint IAEA/ICRU working group regarding
quantities and units, Radiation Protection Dosimetry 122: pp 463 – 470, (2006)
8 NCRP Report No. 142, Operational Radiation Safety Program for Astronauts in Low-Earth Orbit, NCRP,
(2002)
9 SGOUROS, G., HOWELL, R., BOLCH, W. and FISHER, D., MIRD Commentary: Proposed Name for a
Dosimetry Unit Applicable to Deterministic Biological Effects—The Barendsen (Bd), Journal of Nuclear
Medicine 50: pp 485 – 487, (2009)
10 CEMBER, H. Introduction to Health Physics, 2nd edition, Pergamon Press, (1988)
11 LEIKIN, J. B. and McFEE, R. B., Handbook of Nuclear, Biological and Chemical Agent Exposures, CRC
Press, (2007)
12 METTLER, F.A. et al., Medical Management of Radiation Accidents, CRC Press, (1990)
13 ADAMS, M.J., Radiation-associated cardiovascular disease, Critical Reviews in Oncology and
Hematology 45: pp 55-75 (2003)
14 TAKAHASHI, F., ENDO, A. and YAMAGUCHI, Y., Dose assessment from activated sodium within a body in
criticality accidents, Radiation Protection Dosimetry 106: pp 197-206, (2003)
15 CHETTLE, D. and FREMLIN, J., Techniques of in-vivo neutron activation analysis, Physics in Medicine and
Biology 29: pp 1011, (1984)
16 ANDERSON et al., Neutron activation analysis in man in-vivo, Lancet 284: pp 1201-1205, (1964)
17 NCRP Report No. 65, Management of Persons Accidentally Contaminated with Radionuclides, NCRP,
(1980)
18 Annals of the ICRP, Publication 78, Individual Monitoring for Internal Exposure, Pergamon, (1997)
19 The Ionising Radiation Regulations (1999), HMSO, London, (1999)
20 ICRP Supporting Guidance 3, Guide for the Practical Application of the ICRP HRTM, Pergamon (2002)
21 LLOYD, R.D., TAYLOR, G.N., MAYS ,C.W., McFARLAND ,S.S., and ATHERTON, D.R. "DTPA therapy of
241Am from a simulated wound site", Health Physics 29: pp 808, (1975)
22 ROJAS-PALMA, C et al. (Eds), TMT (Triage, Monitoring and Treatment) Handbook, Norwegian Radiation
Protection Authority et al., (2009)
23 THIERENS, H., DE RUYCK, K., VRAL, A., DE GELDER, V., WHITEHOUSE, C.A., TAWN, E.J., and
BOESMAN, I., Cytogenetic biodosimetry of an accidental exposure of a radiological worker using multiple
assays. Radiation Protection Dosimetry 113: pp 408-414, (2005)
24 MENETRIER, F. et al., Treatment of accidental intakes of plutonium and americium: Guidance notes, Applied
Radiation and Isotopes 62: pp 829-846, (2005)
25 WOOD, R., SHARP, C., GOURMELON, P., LE GUEN, B., STRADLING, G., TAYLOR, D., and HENGENAPOLI, M., Decorporation Treatment – Medical Overview, Radiation Protection Dosimetry 87: pp 51,
(2000)
26 LIST, V. (Karlsruhe Research Centre, Germany), Presentation at TIARA Training Course, IRSM in Paris, 5-6th
(February 2007)
27 CROSBIE, W.A. and GITTUS, J.H. (Eds), Medical Response to Effects of Ionising Radiation, Elsevier,
(1989)
28 LAGERQUIST, C.R., HAMMOND, S.E., PUTZIER, E.A. and PILTINGSRUD, C.W. Effectiveness of early
DTPA treatments in two types of plutonium exposures in humans, Health Physics 11: pp 1177, (1965)
29 GRDINA, D.; Amifostine: Mechanisms of Action Underlying Cytoprotection and Chemoprevention, Drug
Metabolism and Drug interactions 16: pp 237–280, (2000)
47
30 GRDINA, D. et al.; The Radioprotector WR-2721 reduces neutron-induced mutations at the hypoxanthineguanine phosphoribosyl transferase locus in mouse splenocytes when administered prior to or following
irradiation, Carcinogenesis 13: pp 811-814, (1992)
31 TABACHNIK et al., Studies on the Reduction of Sputum Viscosity in Cystic Fibrosis using an Orally Absorbed
Protected Thiol, Journal of Pharmacology and Experimental Therapy 214: pp 246-249, (1980)
32 MUSCATELLO, Nutritional Supplements as Radioprotectors, Los Alamos Laboratory, (1998)
33 SCHOFIELD, G.B., HOWELLS, H., WARD, F., LYNN, J.C. and DOLPHIN, G.W. Assessment and
Management of a plutonium contaminated wound case, Health Physics 26: pp 541, (1974)
34 Annals of the ICRP, Publication 66, Human Respiratory Tract Model for Radiological Protection,
Pergamon, (1994)
35 SCHOFIELD, G.B. and LYNN, J.C., A measure of the effectiveness of DTPA chelation therapy in cases of Pu
inhalation and wounds. Health Physics 24: pp 317, (1973)
36 OAK RIDGE INSTITUTE FOR SCIENCE AND EDUCATION, DTPA Informational Package Insert, (2002)
37 STATHER, J.W., SMITH, H., JAMES, A. and RODWELL, P., The experimental use of aerosol and liposomal
forms of CaDTPA as a treatment for plutonium contamination, Diagnosis and Treatment of Incorporated
Radionuclides, IAEA Publication 411, (1976)
38 PELCTAVA, D. and FENCLOVA, Z. Occupational Contamination with americium and Ca-DTPA treatment,
Radioprotection 39: pp 384, (2004)
39 BREITENSTEIN, B.D., FRY, S.A. and LUSHBAUGH, C.C., DTPA Therapy; The US Experience 1958-87:
The Medical Basis for Radiation Accident Preparedness
40 SLOBODIEN,M.J., BRODSKY,A., KE, C.H. and HORM, I. Removal of zinc from humans by DTPA chelation
therapy, Health Physics 24: pp 327, (1973)
41 MULLER, D., HOUPERT, P., HENGE NAPOLI, M., METIVIER, H., and PAQUET, F., Synergie potentielle
entre deux toxiques renaux: le DTPA et l’uranium, Radioprotection 41(4): pp 413 – 420, (2006 )
42 HOUPERT, P., MULLER, D., CHAZEL, V., CLARAZ, M. and PAQUET, F., Effect of DTPA on the
nephrotoxicity induced by uranium in the rat, Radiation Protection Dosimetry 105: pp 517-520, (2003)
43 MORGAN, C., BINGHAM, D., HOLT, D., JONES, D., LEWIS, N., Therapeutic Whole Lung Lavage for Inhaled
Plutonium Oxide Revisited, In Press with Journal of Radiological Protection, (2009)
44 LEGGETT, R.W., The Behaviour and Chemical Toxicity of U in the Kidney: A Reassessment, Health Physics
57: pp 365-383, (1989)
45 The Royal Society Policy Document 6/01, The health hazards of depleted uranium munitions, (2001)
46 Internal AWE Documentation, used in Chapter 4:
i.
ii.
iii.
iv.
v.
vi.
vii.
viii.
ix.
x.
xi.
xii.
xiii.
AWE, Medical Treatment of RA Material Intakes at AWE, issue 2, Unpublished, (2008)
AWE/TMS, Emergency Treatment for RA Intakes – Health Physics Information, issue 1,
Unpublished, (2007)
AWE, Review of Arrangements for Dealing With Contaminated Casualties at AWE and the
Royal Berkshire Hospital, issue 1, Unpublished, (2009)
AWE, Health physics emergency response (manning) during a radiation incident/ accident/
emergency, issue 3, Unpublished, (2008)
AWE, Health physics emergency response plan, issue 1, Unpublished, (2007)
AWE, Health physics emergency response strategy, issue 1, Unpublished, (2007)
AWE, Health physics general work instruction no. E/03 Response to a glove failure incident,
issue 3, Unpublished, (2005)
AWE, Health physics general work instruction no. E/05 Decontamination of contaminated
persons, issue 4, Unpublished, (2005)
AWE, Health physics general work instruction no. E/06 Response to a wound in a
contamination controlled area, issue 3, Unpublished, (2006)
AWE, X Facility Local Rules, issue 7, Unpublished, (2009)
AWE, Response to a Glove Failure in the X Facility, issue 4, Unpublished, (2009)
AWE, Response to X facility alarms and emergencies, issue 8, Unpublished, (2008)
AWE, AP2/4 Alpha Probe Instrument Data Sheet, Unpublished
48
xiv.
AWE, Y Local Work Instruction – Health Physics Procedures for Z, issue 2, Unpublished,
(2009)
47 Annals of the ICRP, Publication 68, Dose Coefficients for Intakes of Radionuclides by Workers ,
Pergamon, (1994)
48 Who will survive a nuclear attack?, New Scientist, 11th July 2009, Pages 8-9
Background Texts:
49 Dictionary of Physics & Mathematics, McGraw-Hill, (1978)
50 LILLEY, J., Nuclear Physics, Wiley, (2001)
51 KRANE, K. S., Introductory Nuclear Physics, Wiley, (1988)
49