Dosimetry Research

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Dosimetry

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PROJECT

SYNOPSES

EUR 21233


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EUROPEAN COMMISSION

Dosimetry Research


2006 EURATOM EUR 21233


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Table of Contents

Preface 4Summary 5

Introduction 6

Development of Radiation Protection Requirements 7

Quantities and Units 8

External and Internal Exposure 9

Objectives and Scope of Dosimetric Research 11

Research Outcomes 12

The 6th Framework Programme 18

Section 1 Internal Exposure 19

IDEAS 20

IDEA 22

BIODOS 26

RBDATA-EULEP 28

OMINEX 32

Section 2 External Exposure 37

EVIDOS 38

INDOOR DOSE 40

INTCOMPSILENE 42

QUADOS 44

Section 3 Natural 49

SMOPIE 50

DOSMAX 54

TENORMHARM 56

Section 4 General 61

DOSIMETRY NETWORK 62

Index by Acronym 66

Index by Co-ordinator 67


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PREFACE

The European Commission has supported research into the dosimetry of io-

nising radiation for radiation protection purposes for a number of years. This

brochure has been prepared to disseminate to a broad non-technical audience

the objectives and main results of research carried out under the 5th Framework

Programme, and to set these results in a wider context. This should enable the

reader to appreciate the origins of, and needs for, research in this area and to

appreciate the uses to which the results will be put.

Underlying all practical radiation protection is the need to be able to accurately

monitor the radiation exposure of people. This general process of monitoring

exposure is known as radiation dosimetry. In this programme the main focus

is on measuring the radiation doses of those working with radiation, called

occupational exposures, although the techniques developed would be appli-cable in other circumstances in which people were exposed and monitoring was

required. As radiological protection has developed, and in particular the basic

requirement to maintain radiation exposures as low as reasonably achievable

(the ALARA principle) has been applied to the control of occupational expo-

sure, actual doses have fallen. While this is undoubtedly a matter of success

it has meant that the doses being measured have fallen to levels at which the

ability to accurately monitor them has challenged the dosimetry profession. The

advances made during this programme of research have helped to ensure that

accurate monitoring of doses to workers is still possible even at current low

levels of exposure.

This brochure is divided into two parts. The first provides a summary and review

of Commission supported research into radiation dosimetry over the period of

the 5th Framework Programme but setting this in a wider context. The second

part describes in more detail the objectives and main achievements of each of

the supported projects.


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SUMMARY

This brochure summarises the research supported by the European Commission

into the dosimetry of ionising radiation for radiation protection purposes under

the 5th Framework Programme. The brochure describes the objectives and main

results of this research and sets the results in a wider context. This is intended

to enable the reader to appreciate the origins of, and needs for, research in this

area and to appreciate the uses to which the results will be put.

This brochure is divided into two parts. The first part starts with an introduc-

tion to the objectives of dosimetry in the particular context of the radiation

protection of workers, and an explanation of the quantities and units used in

protection and operational dosimetry. It continues with a summary of Commis-

sion supported research in this area in the 5 th Framework Programme and the

nature and scope of that being supported in the 6th Framework Programme. Thesecond part describes in more detail the objectives and achievements of each

of the supported projects, with information on the effectiveness of the partner-

ships formed to carry out the research.

The overall purpose of dosimetry is to estimate radiation doses to people,

usually workers with radiation or radioactive materials, for the purposes of pro-

tection. These estimates of dose enable the management, the regulators, and

indeed the workers themselves to assess the effectiveness of radiation protec-

tion actions and procedures against targets and requirements and to quantify

successes and the need for improvements. In some cases the results of dosim-

etry have legal significance, emphasising the importance of accuracy and of

good quality management in providing dosimetry services. Underlying all these

practical applications has been and continues to be an on-going programme of

dosimetry research.

The main objectives of radiation protection for workers and the public are to

ensure compliance with the appropriate dose limits and further to ensure that

all doses are As Low As Reasonably Achievable (ALARA). The successful ap-

plication of the latter principle has meant that the actual doses to workers are

in many cases low so that the demands on dosimetry for their measurement,

especially of internal exposures, are increasing. Also more attention is beingpaid to protection against natural radiation and to protection in mixed radiation

fields. All of these aspects are addressed as part of this research programme.

Dosimetry for external radiation is a well developed discipline, especially the

use of passive individual dosimeters. The research in this area has therefore

concentrated on the development and use of active, real-time dosemeters, mea-

surements in mixed fields such as those to which aircrew are exposed, and

dosimetry in accident situations. For internal dosimetry, further development of

knowledge of radionuclide bio-kinetics has been the driving force for a number

of projects, together with methods for optimising monitoring. More general as-

pects are also covered including quality assurance and the need to maintain anddevelop networks of professionalism to ensure European research continues to

be of world quality.


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1. Introduction

From the earliest discovery of radiation and radioactivity those involved havetried to measure the intensity of the radiation field and the radiation exposure

to people. Even in the early years of the last century radiation protection objec-

tives were set out in quantitative terms that needed physical dosimetry tech-

niques to demonstrate whether or not people were being protected from the

harmful effects of radiation exposure. One of the earliest techniques was to use

photographic film, which is sensitive to ionising radiation of all types as well as

to light, and relate the blackening of the film to the quantitative radiation dose.

Thus the discipline ofradiation dosimetrywas born.

Over the years this technique has been refined and other physical dosimetry

techniques have been developed. These techniques are all aimed at measuring

the external radiation from exposure to radiation fields in the ambient environ-

ment and improvements are still required to achieve the necessary precision.

There is also, however, the possibility of people experiencing internal irradia-

tion from the incorporation of radioactive materials in the body, principally by

inhalation or ingestion. Measurement of such internal exposures is very much

more difficult than for external exposures and remains one of the main focuses

of dosimetry research.

One important thing to realise about dosimetry is that it is not an end in itself,

but a means to an end. The overall purpose of dosimetry is to estimate radia-tion doses to people, usually workers with radiation or radioactive materials,

for the purposes of protection. These measurements enable the management,

the regulators, and indeed the workers themselves to assess the effectiveness

of radiation protection actions and procedures against targets and requirements

and to quantify successes and the need for improvements. In some cases the

results of dosimetry have legal significance, emphasising the importance of ac-

curacy and of good quality management in providing dosimetry services. Under-

lying all these practical applications has been and continues to be an on-going

programme of dosimetry research.

Dosimetry and measurement of radiation is a component of many specific areas

of research and is more appropriately reported on in context. For this reason

some research that could be categorised as dosimetry is reported in previ-

ous brochures concerned with Community radiation protection research. Retro-

spective dosimetry is for example addressed in the brochure on epidemiology1,

airborne gamma monitoring in the brochure on emergency management2 and

medical dosimetry in the brochure on optimisation of protection in the medical

uses of radiation3.

1. Radio-epidemiology, EUR 19958, Luxembourg, 2002.2. Decision support for emergency management and environmental restoration, EUR 19793, 2002.3. Optimisation of protection in the medical uses of radiation, EUR 19793, 2002.


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2. Development of Radiation Protection Requirements

Modern radiation protection came into being with the rapid development ofatomic energy and medical and other industrial applications of radiation after

the Second World War in the 1950s and 1960s. At this time the International

Commission on Radiological Protection (ICRP) was structured in essentially its

current form and started issuing recommendations that have formed the basis

for radiation protection standards world-wide ever since. These standards in-

corporated quantitative limits of radiation exposures of workers and members

of the public from their beginning with the clear expectation that for workers

compliance with the limits would be demonstrated by dosimetry programmes.

From at least the 1970s the limits have been complemented by the additional

requirement for optimisation of protection, often referred to as the ALARA

principle after the core statement in the requirement that all doses be kept as

low as reasonably achievable... The current statement of the relevant radiation

protection principles dates from 19904 and is the basis for the requirements in

the current Euratom Directive5.

Basic radiation protection requirements

Although the dose limits are important, especially as they are normally enforce-

able in law, compliance with them is, in most occupations, almost fully achieved

so the major focus of radiation protection is now on the optimisation of pro-

tection. This has been very successful in reducing actual doses as was demon-

strated very clearly during a international conference on occupational radiation

protection6. However, as a result, the doses to which workers are exposed have

decreased with a commensurate increase in the difficulty of making measure-

ments. Thus the demands on dosimetry have increased, necessitating further

research to improve the dosimetry capability.

4. ICRP Publication 60. Annals of the ICRP Vol 21. Nos 1-3, 1991.5. Council Directive 96/29 EURATOM, Off. J. Eur. Communities 39 L15929, 1996.6. Occupational Radiation Protection: Protecting Workers against Exposure to Ionizing Radiation, Int. Conf,

Geneva, 26-30 August 2002. IAEA, 2003.

The 1990 Recommendations of the ICRP relevant to dosimetry.

The optimisation of protection. In relation to any particular sourcewithin a practice, the magnitude of individual doses, the number of people

exposed, and the likelihood of incurring exposures where these are not

certain to be received should all be kept as low as reasonably achievable,

economic and social factors being taken into account.

Individual dose limits.The exposure of individuals resulting from the

combination of all the relevant practices should be subject to dose limits.

The dose limit for workers is an effective dose of 20mSv per year.


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3. Quantities and Units

The system of dose quantities used in radiation protection and radiation dosim-etry is quite complex but a clear understanding of the relevant quantities and

units and how they relate to each other is crucial to appreciating the goals of

much dosimetry research.

3.1 Radiation protection dosimetric quantities

The fundamental way in which radiation interacts with tissue is by energy de-

position. The basic dosimetric unit measures energy deposition in unit mass

of tissue and is called the absorbed dose. Ionising radiations, however, dif-

fer in the way in which they interact with biological materials so that equalabsorbed doses, that is equal amounts of energy deposited, do not have the

same biological effects. For example, an absorbed dose of 1 Gy to tissue from

alpha radiation is more harmful than 1 Gy from beta radiation because an alpha

particle, being slower and more heavily charged, deposits energy much more

densely along its path. This is taken into account by weighting different radia-

tions according to their potential for causing harm to give the equivalent dose.

For gamma rays, x-rays and beta particles this radiation weighting factor is set

at 1 whereas for alpha particles it is set at 20. Values of the radiation weighting

factor for neutrons are a function of the neutron energy and range from 5 to

20. A further weighting is needed to take account of the susceptibility to harm

of different organs or tissues. For example the risk of fatal malignancy per unit

equivalent dose is higher for the lung than for the thyroid. Furthermore there are

other types of harm such as non-fatal cancers or hereditary effects for irradiation

of the testes or ovaries. All of these have to be taken into account in producing

a quantity that reflects reasonably well the overall detriment to health of human

beings from exposure to radiation. This is done by taking the equivalent dose

in each of the major organs or tissues of the body and multiplying it by a tissue

weighting factor. Tissue weighting factors (which represent the risk from irradia-

tion of that tissue relative to that for irradiation of the whole body) range from

0.20 for the gonads to 0.01 for skin and bone surface. The result is the doubly

weighted quantity known aseffective dose

, which applies equally to external

and internal irradiation and to uniform or partial body exposure.

Radiation protection dosimetric quantities

Absorbed dose. The energy imparted by radiation to unit mass of tissue.

The basic unit is joules/kg given the special name Gray (Gy).

Equivalent dose. Absorbed dose weighted for the harmfulness of differ-

ent types of radiation. The special unit is the Sievert (Sv).

Effective dose. Equivalent dose weighted by the susceptibility to harm ofdifferent organs or tissues. The special unit is also the Sievert (Sv).


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3.2 Operational Dosimetric Quantities

One of the basic problems of dosimetry is that it is not possible to measure thebasic protection quantities, neither the equivalent dose nor the effective dose,

so that use has to be made of other quantities that can be measured together

with protocols to convert the measurements to results that can be compared

with protection requirements. The operational quantities (personal dose equiva-

lent, ambient dose equivalent and directional dose equivalent) used in dosim-

etry have been defined by the sister commission to the ICRP, the International

Commission on Radiation Units and Measurements (ICRU). These operational

quantities are directly measurable, and are intended to provide a reasonable

estimate of the protection quantities in assessing compliance with the limits 7.

In general, the measured operational quantities adequately represent the pro-

tection quantities. However, there are four groups of radiations for which this

is not the case and further work is needed. These are: electrons and photons

of low energy; intermediate-energy neutrons; high-energy neutrons; and other

high-energy radiations such as are found at altitude.

4. External and Internal Exposure

As was mentioned in the Introduction people are subjected to two different

types of exposure. By far the most common form of exposure of people working

with radiation sources is external exposure. This results from the person being

in a radiation field from a source external to the body. The field may be of anytype of radiation; gamma, x-ray, beta, alpha, neutron or even heavy particles,

muons, etc. or any mixture of different types. Exposure to external fields is usu-

ally monitored by means of individual dosimeters positioned on the body. The

type of dosimeter used will depend on the fields and radiation types expected

to be encountered. Individual monitoring can be complemented by area moni-

toring. Until recently most individual dosimeters were passive devices but there

is an increasing trend towards the use ofactive direct-reading dosimeters.

7. Quantities and Units in Radiation Protection Dosimetry. ICRU Report 51. 1993.


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Active and passive dosimeters

If radioactive materials are taken into the body they will deposit in organs or tis-sues until they are excreted. The exposure they cause is known as internal expo-

sure. The behaviour of each radionuclide is different, depending on the chemical

and physical behaviour of the element or compound in the body; the dose will

depend on where and for how long the radionuclide resides in the body and

on its radiation emission characteristics. Thus, the monitoring and estimation of

dose from incorporated radionuclides is extremely complex.

Passive DosimetersThe first type of individual dosimeter for monitoring the dose to individual

workers was the film badge. This was the classic passive dosimeter in

which the amount of blackening of the film when it was developed could

be related to the total radiation dose to the wearer over the issue period.

The other main type of passive dosimeter is the thermoluminescent dosim-

eter (TLD) in which the light emitted by a phosphor on subsequent heating

(readout) indicates the total dose. The key common feature of all passive

devices is that they have to be processed at the end of the issue period and

indicate the total accumulated dose over that period. Until recently passive

dosimeters were the only legally recognised form of monitoring.

Active Dosimeters

Although passive dosimeters have always been worn by workers, it was

recognised that there was also a need for some form of dosimeter that

would either give a warning when a preset dose or dose-rate was reached

or even indicate the accumulated dose in real time. The most common

such early device was the quartz-fibre electroscope (QFE). This used one

of the first techniques for measuring radiation, which was to optically

measure the decay of charge in a small chamber. These were not very

robust, sensitive or precise but did the job. Naturally there was a move to

more sensitive dosimeters but as these required batteries and some elec-tronics the early active dosimeters were bulky and rather simple in what

they could do. Recent developments have however resulted in relatively

small and lightweight active dosimeters that can indicate dose-rate and

accumulated dose in real time. Indeed some are now recognised as legal

dosimeters for record-keeping purposes eliminating the need to wear

both an active and passive dosimeter. The common feature of all active

devices is that they give information in real-time of accumulated dose

and/or dose-rate that is available to the wearer.


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One particular circumstance of exposure to incorporated radionuclides is from in-

halation of radon gas and to a lesser extent of thoron gas. This gas is naturally oc-

curring and ubiquitous and there are many circumstances in above-ground work-places as well as underground in which it causes the highest radiation exposure

of the workers involved. The dosimetry of radon and the radon daughters that

actually deposit in the lung is a particularly important and difficult area of study.

There are some circumstances in which the distinction between external and

internal exposure is somewhat blurred. These relate to contamination, especially

on the skin. Radionuclides that are deposited on the skin will cause localised

external exposure but the dose will be highly localised and not measurable by

normal external dosimeters. Some radionuclides are also absorbed through the

skin, either directly or via wounds, leading to internal exposures. This is another

particularly difficult situation in which to make dose estimations.

5. Objectives and Scope of Dosimetric Research

As indicated previously, there are elements of dosimetric research embedded

within most if not all of the thematic areas of the programme concerned with ra-

diation protection. Previous brochures have already covered dosimetry research

carried out as an integral, but supporting, part of broader topical areas (i.e.

emergency management, optimisation of medical exposures, epidemiology). The

scope of this brochure, with one exception, is limited to research whose objec-

tives had an explicit dosimetric focus. The exception concerns projects (with asignificant dosimetric component) concerned with natural radiation; these have

not been addressed in previous brochures and are included here for completeness.

Two areas of the programme were explicitly focused on dosimetric research.

The first was part of the Key Action on Nuclear Fission; this research was ap-

plied in nature and was concerned with improving the monitoring and assess-

ment of exposures in the workplace. The second was carried out as part of a

broader programme of generic research on radiological sciences; this research

was more basic in nature and was concerned with improving methods for as-

sessing doses.


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Radiation protection research explicitly focused on dosimetry

6. Research Outcomes

The main outcomes of the dosimetric research are summarised below and are,

for convenience, subdivided into four separate topics: internal exposure; ex-

ternal exposure; natural radiation and more general cross-cutting issues. Both

applied and more fundamental research relevant to a given topic are addressed

together, notwithstanding the fact that the programme was structured differently.

Further information on each project can be found on http://www.cordis.lu/fp5-euratom/src/lib_finalreports.htm.

6.1 Internal exposure

The key objectives in this area are development of faster and more reliable

in-vivo and bio-assay monitoring techniques, better operational monitoring of

individual intakes and practicable methods for the optimisation of internal ex-

posures. In moving from the measured data to an estimate of intake a number

of models and assumptions are involved. Recent inter-comparison exercises on

the assessment of internal doses from sets of monitoring data have shown verywide ranges in results from different laboratories. One of the projects, IDEAS,

aims to harmonise these so that the same estimate of intake is obtained from

Monitoring and assessment of occupational exposure

(more applied research)

Objectives: to improve the monitoring and assessment of exposures to

radiation in the workplace, thereby providing better protection and use of

human resources.

Scope: development of:

active individual monitors for exposure to complex radiation fields

(ie, neutrons plus gamma);

methods for dose assessment to improve design and operation of

workplaces;

faster and more reliable in-vivo and bio-assay monitoring techniques

Internal and external dosimetry (more basic research)

Objectives: to improve methods for assessing exposures to radiation from

external and internal sources

Scope:

internal exposure - improve the scientific basis of bio-kinetic and do-

simetric models and the relationship between measurable quantities

and individual dose

external exposure develop new techniques that have substantial

advantages in cost or performance

retrospective dosimetry improve and standardise techniques to assesspast chronic individual exposures for use in epidemiological studies


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the same measured data. The procedure is to assemble a collection of case

studies into a database that contains information on over 200 cases, which will

be analysed by a number of participating laboratories through the 4th

EuropeanInter-comparison of Internal Dose Assessment. The overall approach is compat-

ible with that being used by an ICRP working party with which there is some

useful overlap in membership, thereby enabling the results of this research to

find world-wide application through ICRP.

Titles and acronyms for the Projects on Dosimetry

As specified in the objectives, sophisticated new techniques for in-vivo and

bioassay measurements need to be introduced into routine applications in op-

erational monitoring. These should result in increased speed of analysis and re-

duced Lower Limits of Detection together with more reliable calibrations. The

project, IDEA, concentrated on problems, such as measuring low energy electron

emitters in partial body exposure, which could be solved by implementing exist-

ing advanced techniques. The results show that anthropomorphic and numerical

phantoms are capable of reducing total uncertainty significantly, especially for

low energy gamma emitters.

Internal exposure

IDEAS (General guidelines for the estimation of committed effective dose

from incorporation monitoring data).

IDEA (Internal Dosimetry Enhancements in Application)BIODOS (Biokinetics and dosimetry of internal contamination)

RBDATA-EULEP (Radionuclides Biokinetics Database EULEP)

OMINEX (Optimisation of Monitoring for Internal Exposure)

External exposure

EVIDOS (Evaluation of Individual Dosimetry in mixed neutron and photon

radiation fields)

INDOOR DOSE (Quantification of the distribution of radiation doses

received by humans through the various pathways in a contaminated

indoor environment)

INTCOMPSILENE (International accident dosimetry inter-comparison

exercise at Silene)

QUADOS (Quality assurance of computational tools for dosimetry)

Natural

SMOPIE (Strategies and Methods for Optimisation of Internal Exposures

of Workers from Industrial Natural Sources)

DOSMAX (Dosimetry of Aircrew Exposure to Radiation during Solar Maximum)

TENORMHARM (New approach to assessment and reduction of health risk

and environmental impact originating from TENORM according to

requirements of EU Directive 96/29/Euratom)

General

DOSIMETRY NETWORK (Radiation dosimetry network)


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Improved methods are also needed for prospective and retrospective assessment

of doses to all age groups using physiologically realistic models. The project,

BIODOS, has operated in close collaboration with two ICRP Task groups havingthe same objectives. The new models describe in a more realistic manner absorp-

tion, retention and excretion of radionuclides for adults and children, respiratory

tract deposition and clearance, systemic circulation and transfer to breast milk

for lactating mothers. Furthermore, special attention was given to the quantita-

tive assessment of non-uniformities in internal exposure to short range emitters

and their consequence for the assessment of internal dose. Overall, this work is

providing a substantial body of new information on radionuclide behaviour in

the human body and new or improved approaches to biokinetic modelling. This

should lead to improved confidence in the calculation of radiation doses and the

assessment of risks following accidental or environmental intake of radionuclides,

by workers or members of the public, including young children.

There is a great deal of information in the literature related to assessments of

intakes and doses. A project, RBDATA-EULEP, was therefore developed that aims

to systematically provide an annotated database with summaries of and access

to this wealth of data with eventually on-line access. An existing database de-

veloped during the 4th Framework Programme has been expanded to about 1500

experiments from over 500 publications covering the fields of interest, materials,

methods and results. It is an important means of capturing and retaining knowl-

edge from scientists who are retiring as many of the publications are from obscure

sources not found by normal searches. The main users are expected to be the

ICRP task group on internal dosimetry, research scientists and health physicists.

By optimising the design of internal monitoring programmes it is possible to

maximise the accuracy while at the same time minimising the costs. The primary

aim of the project, OMINEX, designed to tackle this problem is to provide advice

on the design and implementation of internal dose monitoring programmes in

the workplace. This is achieved by the appropriate choice of monitoring method,

whether whole body monitoring, lung monitoring, urine monitoring etc., of mea-

surement technique and of monitoring procedure such as measurement times

for chronic exposure or monitoring intervals after an incident. In developing

advice a number of novel approaches were developed and implemented, espe-cially to quantify total uncertainty in the measured quantities, and then to opti-

mise the measurement parameters themselves. The results of the investigations

have been presented at a training course and will be collected on CD-ROM so

that they can be available for repeated use.


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6.2 External dosimetry

There are more than 60,000 workers exposed to mixed fields in Europe exclud-ing aircrew. The improvement of measurements in these circumstances, includ-

ing development of active individual monitors for exposure to complex radia-

tion fields, is one of the objectives of the programme. Individual dosimetry for

neutrons is a less well established procedure than for photons and has tended

to rely on passive devices. Recently a number of types of active device have

been developed and the purpose of the project, EVIDOS, is to evaluate them

in comparison with established passive systems. To do this it was necessary to

fully characterise a simulated workplace facility and a thermal neutron standards

field before making measurements in workplaces representing typical facilities.

The final results of the project will be innovative prototype instruments for en-

ergy and directional spectroscopy, a comprehensive set of data for workplaces

and an analysis of dosemeter performance to enable their suitability for use in

specific circumstances to be assessed.

Quality assured measurements are a fundamental requirement for good dosim-

etry. The project, QUADOS, has the specific objective of improving the qual-

ity of computational tools and harmonisation of computational dosimetry. The

initial focus is on radiation transport codes using Monte Carlo techniques for

testing, with particular emphasis on the handling of uncertainties in input data

such as cross-sections and conversion factors and in calculational codes. The

procedure was to design eight reference problems representing real situationsincluding brachytherapy, personal dosimetry and environmental scatter from a

Cf-252 source in a bunker. The results were presented and discussed in an initial

workshop in July 2003.

Until relatively recently it was not generally recognised that the gamma and

even beta doses from skin contamination after an accident may be comparable

with those from plume inhalation or from the first year of exposure to external

deposition on the ground or other surfaces. The project, INDOOR DOSE, aims

to improve the knowledge of the mechanisms that determine the contributions

to dose in a contaminated indoor environment. The influence on aerosol de-

position of a number of physical parameters has been examined and the rates

of clearance and penetration mechanisms for deposited contaminants. These

results, with further investigations of the redistribution of indoor contamination,

will be integrated in a model that can be applied to estimate the various contri-

butions to dose in the indoor environment.


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An intercomparison exercise, INTCOMPSILENE, has been undertaken to check

and evaluate criticality dosimetry systems under realistic conditions and for dif-

ferent neutron/gamma fields so as to improve techniques and interpretations.The SILENE facility at Valduc is a liquid fissile solution with variable shielding

that produces a mixed neutron/gamma field and can be operated pulsed, free

to simulate a criticality accident, or steady state. The field has been character-

ised using TLDs, activation detectors and neutron spectrometers. There is also

a capability to produce very high intensity pure gamma fields using the 47 TBq

Co-60 source at IRSN. Altogether 60 laboratories from 29 countries took part

in the intercomparison. The dosimetry systems used were mainly TLDs, albedo

and activation detectors but there were some biological systems. The measure-

ments comprised photon doses, area doses, fluence and spectra on phantoms

and free in air. The results are currently being compiled and will be published

with a critical analysis.

6.3 Natural radiation

There are many different practical exposure circumstances involving Naturally Oc-

curring Radioactive Materials (NORM) which all need recommendations of moni-

toring strategies and methods. There is limited information in national databases

on the number of workers exposed and the levels of exposure from personal or

static air samplers but the dose estimates are generally scenario based conserva-

tive estimates. The first part of the project, SMOPIE, was to estimate the number

of workers exposed above 1mSv/a to internal exposure from NORM industries, ex-cluding radon progeny exposure. This was surprisingly difficult but indications are

that there are about 100,000 workers of whom 70,000 were in the production of

thoriated electrodes and 12,000 producing phosphate fertilisers. A number of case

studies involving uranium, thorium, radium, polonium-210 and lead-210 will be

analysed to focus on some common characteristics, such as dust levels and work

patterns, and use them to review monitoring tools and strategies for optimisation.

This will lead to recommendations for the optimum monitoring strategies and to

direct the development of improved monitoring devices.

The project, TENORM (Technologically Enhanced NORM), seeks eventually to achieve

harmonisation of regulations for NORM and among all European Member States and

to compare mitigation methods. For this purpose TENORM is defined as solid ma-

terials with more than 200 Bq/kg, which implies doses of the order of 1 mSv/a. The

initial task is to determine the sources, levels and inventories. The sectors consid-

ered include the phosphate industry, mining and processing of metals and mineral

sands, thorium uses, titanium dioxide pigments, oil and gas production, coal mining

and water treatment. The amounts can be very large but generally the levels are low,

although this depends crucially on the origin of the raw material being processed.

The project then moves into dose assessment, remediation and monitoring with the

final step being harmonisation of regulations.


19/7117

Cosmic radiation levels are relatively stable and predictable so doses to aircrew

can be reasonably estimated from rostering data combined with models for short-

haul and long-haul flights. The characteristics are however unusual with about50% of the exposure to high LET radiation including neutrons of up to 10 10 eV.

About half of those exposed are female workers. The calculations need to be veri-

fied and supported by measurements. The project, DOSMAX, continued relevant

measurements through the solar maximum period of 2000-2003, which was ex-

pected to include more solar particle events and more magnetic field disturbances.

The instrumentation has been characterised and intercompared despite problems

obtaining suitable calibration beams and the development of suitable calibration

protocols. In-flight readings are now being compared with calculations.

6.4 General

A thematic network, DOSIMETRY NETWORK, coordinated by EURADOS (European

Radiation Dosimetry Group) is providing an important forum for maintaining and

enhancing dosimetric competence and capability in Europe. At present there are

some 47 institutes or oganisations that are members of the network from 26

countries and about 100 actively participating scientists. The network provides

mutual information on a wide range of facilities for dosimetry research. A long-

term objective is harmonisation of individual monitoring in Europe by collecting,

evaluating and disseminating information on occupational dose assessment, us-

ing combined results from personal dosimeters, workplace monitors and, where

necessary, internal dosimetry. This should lead to a standing network of expertson personal dosimetry. Similarly for environmental monitoring, inter-comparisons

are being carried out involving a number of Central and Eastern European coun-

tries, with the intention of harmonising across national boundaries and develop-

ing a lasting capability within the EU. Aircrew dosimetry is another area in which

the facilities of the network have been utilised by the European Commission and

the Article 31 Group of Experts. Considerable emphasis is placed on dissemination

of information through workshops/conferences and publications and a newsletter

jointly edited with EULEP (European late effects project group).

The existence of this network has promoted and facilitated highly effective

collaboration and exchange between the various dosimetry projects and their

participants. This has contributed substantially to the maintenance and develop-

ment of European capability in an area of work that is fundamental to achieving

good radiation protection for the very large number of workers in the European

Union. Often this collaboration extends beyond the European Union underlining

the importance of European research at the global level; this is best exemplified

by 9 of the 47 members of the dosimetry network being from countries outside

of the Union. Significant cost savings have also been achieved through the shar-

ing of expensive facilities and the spreading of understanding.


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7. The 6th Framework Programme

In the 6th Framework Programme, the main focus of radiation protection research

is to resolve uncertainties in the risk from exposures to radiation at low and

protracted doses. In all other thematic areas, including dosimetry, the objective

is to make better use of national efforts, principally through their more effec-

tive integration through networking and targeted research where this would be

either complementary to, or provide synergy with, national programmes.

As in the 5th Framework Programme dosimetric research is embedded in many of

the supported projects (e.g. epidemiological studies, medical exposures, protec-

tion of the workplace, emergency management, etc.)8. Unlike the 5th Framework

Programme, dosimetry is not included explicitly as a distinct, self-contained

thematic topic. This is understandable given the main focus and goals of the

research programme and recognising that dosimetry is not an end in itself but,

rather, a means to an end. Dosimetric research is now more intimately involved

with the end results required than hitherto. Effective networking of dosimetric

research in the Union remains an important objective and support is being given

for this in the context of protection in the workplace. The network will address

a number of important challenges facing the operational radiation protection

community and explore how the efficacy of the networking could be further

enhanced and greater self sustainability achieved. This will provide a good plat-

form for research in this area beyond the 6th

Framework Programme.

8. Euratom Research Projects and Training Activities, Volume I and II, EUR 21228 and 21229(also see http://www.cordis.lu/fp6-euratom/projects.htm).


21/71

Section 1Internal Exposure


22/7120

General Guidelines for the Estimationof Committed Dose from IncorporationMonitoring Data IDEAS

Challenges to be met

Recent intercomparison exercises on bioassay data interpretation have shownthat there are a wide variety of assessment procedures, depending on the ex-

perience and the skill of the assessor as well as on the hardware and software

tools. However, for a given set of internal monitoring data there can be only

one best estimate of the intake and the committed effective dose. The main

challenge of the project is therefore to enable all assessors to derive the same

standard estimate for any given set of data. This is of great importance for the

harmonisation of internal dose assessment in Europe, and elsewhere. To meet

this challenge, a general philosophy for the assessment of monitoring data has

to be developed from the practical experience of the scientific community taking

into account the recommendations of the ICRP. There are also many scientific

and technical challenges involved in meeting this overall objective. These in-

clude deciding when to use specific, rather than default parameter values (e.g.

particle size, dissolution rates) according to the situation or the likely dose;

which parameters to vary to obtain a model that fits the data; and data han-

dling issues (e.g. treatment of data below the limit of detection, identification

of unreliable data and additional intakes).

Achievements

To ensure that the guidelines are applicable to a wide range of practical situa-

tions, a database was compiled of cases of internal contamination that include

monitoring data suitable for assessment. The database now contains informa-

tion on over 200 cases, and further cases are being added, because it will form

a valuable resource for training and other purposes. In parallel, improved algo-

rithms (mathematical methods) for assessing intakes and doses from bioassay

data were developed and incorporated in the existing software package IMIE (In-

dividual Monitoring of the Internal Exposure). A special version of IMIE was de-

veloped and distributed to the partners. About 50 cases from the database were

assessed using IMIE, with at least two independent assessments of many of the

cases. The results have been collated, and differences in assumptions identified,

with their effect on the assessed dose. From the results, and other investiga-

tions, draft guidelines will be prepared to provide a systematic procedure for

estimating the required parameter values that are not part of the measurement

data. A virtual workshop will be held on the Internet, open to internal dosimetry

professionals, to describe the database and evaluations, and in particular, to

discuss the draft guidelines. The guidelines will be revised on the basis of the

discussion. An intercomparison exercise on internal dose assessment will then

be conducted, which will again be open to all involved in internal dosimetry.

Several examples from the database will be circulated to participants, with a

copy of the revised guidelines, which participants will be encouraged to follow,

in order to test their applicability and effectiveness. The results will be collated

and a Workshop held to discuss the results with the participants. The guidelineswill be refined on the basis of the experience and discussion, and put forward

as a basis for national and international guidance.

Objectives

Doses from intakes of radionuclides

cannot be measured but must be es-

timated or assessed from monitoring

data, such as whole body counting, uri-

nary or faecal excretion measurements.

Such assessments require application of

a model and estimation of the exposure

time, material properties, etc. The aim

of the project is to develop guidelines

to standardise assessments of internal

doses, based on research into the as-

sumptions made, and developed by a

group of experts in consultation with

potential users.


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Partnership

The problems involved in internal dose assessment are complex and multidisci-plinary, involving chemistry, biology, medicine, physics and statistics. Although the

principal scientific personnel are all involved in internal dose assessment, they

have a wide variety of backgrounds, being qualified in chemistry, radiobiology,

engineering, medicine, pharmacology, and physics. Similarly, their involvement in

internal dose assessment comes from different directions. In most cases it mainly

complements monitoring, both in vivo and bioassay measurements (EDF, ENEA,

FZK, AEKI, SCKCEN). However, in other cases it is mainly related to involvement

in development of models used to relate intakes of radionuclides to organ doses

and excretion (IRSN, NRPB), and/or to development of computer programs to

implement such models and hence to calculate intakes and doses from monitor-

ing data (RPI). The organisations involved have a range of functions: research

institutes (ENEA, FZK, AEKI), national radiation protection authorities (IRSN, NRPB,

RPI, SCKCEN), and nuclear power production (EDF), and so bring different per-

spectives. The trans-European nature of the consortium is shown by the inclusion

of institutes from seven countries, five being member states, one (Hungary) a

candidate for EU membership, and one (Ukraine) is a newly independent state of

the former Soviet Union. In addition, there is an intensive cooperation with the

ICRP Task Group on Internal Dosimetry (INDOS) to ensure that the guidelines are

in agreement with all international recommendations.

Selected references

Doerfel, H., Andrasi, A., Bailey, M., Berkovski, V., Castellani, C.-M., Hurtgen, C., Jourdain,J.-R., LeGuen, B.: Guidance on internal assessments from monitoring data (Project IDEAS),

In: Proc. Workshop Internal Dosimetry of Radionuclides - Occupational, Public and MedicalExposure, 9-12 September 2002, Oxford, UK, J. W. Stather et.al. Eds., Rad. Prot. Dosim. 1051-4 pp. 645-647 (2003).

Doerfel, H., Andrasi, A., Bailey, M., Berkovski, V., Castellani, C.-M., Hurtgen, C., Jourdain,J.-R., LeGuen, B.: Lessons learned from Interlaboratory Comparisons of Bioassay Data Inter-

pretation, In: Proc. Workshop Internal Dosimetry of Radionuclides - Occupational, Publicand Medical Exposure, 9-12 September 2002, Oxford, UK, J. W. Stather et.al. Eds., Rad.Prot. Dosim. 105 1-4 pp. 427-432 (2003).

Project components (Pert diagram)

Project Information

Title:

General Guidelines for the Estimation

of Committed Dose from IncorporationMonitoring Data

Acronym: IDEAS

Co-ordinator:

Hans Doerfel

FZK

Hermann-von-Helmholtz-Platz 1

DE-76344 Eggenstein-Leopoldshafen

Germany

Tel.: +49 7247 82 2083Fax: +49 7247 82 2080


Partners:

C. Hurtgen (Belgian Nuclear Research

Centre, Mol, Belgium)

B. LeGuen (Electricit de France,

Paris, France)

C.-M. Castellani (Ente per le Nouve

Technologie, Bologna, Italy)

J.-R. Jourdain (Institut de

Radioprotection et de Suret

Nuclaire, Paris, France)

A. Andrasi (Atomic Energy Research

Institute, Budapest, Hungary)

V. Berkovski (Radiation Protection

Institute, Kiev, Ukraine)

M. R. Bailey (National Radiological

Protection Board, Didcot,

United Kingdom)

EC Scientific Officer:

Henning von Maravic

Tel.: +32 2 296 52 73

Fax: +32 2 295 49 91


Period Programme:

Nuclear Energy 1998-2002

Status: Completed8PSL1BDLBHF

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24/7122

Internal Dosimetry Enhancementsin Application IDEA


First, the current situation has to be evaluated and the potential for enhance-ment with specific methods in internal dosimetry must be analysed. Within that

analysis, the reasons for non-deployment of technically feasible and already

developed methods will have to be examined. These can be related to cost,

particularly where routine monitoring provides a competitive service, but may

be a mix of various factors.

The two measurement techniques routinely used in internal monitoring programs

to assess dose from incorporated radionuclides are in-vivo counting and bioas-

say analyses. The first is employed for measurements of incorporated gamma

emitters; the latter for radionuclides which do not possess a sufficient gamma

emission signature for in-vivo measurements to be effective. Gamma emitting

radionuclides which are distributed in the whole body are measured using a

whole-body counter while gamma emitters accumulated mainly in specific or-

gans or tissues are analyzed by means of organ counting. Bioassay methods are

employed for the determination of alpha or beta emitters in urine, feces, blood,

or other biological samples.

The proof of compliance with existing laws and regulations required by the authori-

ties and the necessity to provide adequate radiation protection for occupationally

exposed workers are posing challenges for the currently used internal monitoring

techniques. Improvements are sought in cost, accuracy, speed, detection limits,

and the many contributions to the total uncertainty in the activity measurements

as well as in the estimates on radionuclide intake and dose reconstruction.

Achievements

An initial feasibility study concluded that calibration of in-vivo measurement sys-

tems with anthropomorphic and numerical phantoms reduced the total dose as-

sessment uncertainty by about 20%, most importantly for low energy gamma

emitters where individual variability is a significant source of uncertainty. Detailed

studies of the individual background and the biokinetic models in dose assess-

ments by bioassay methods should decrease the total uncertainty by about 25%

for certain radionuclides. Optimized in-vivo detector geometries or new detector

materials are expected to improve the lower limit of detection significantly for

low energy gamma emitters. The use of Inductively Coupled Plasma Mass Spec-

trometry (ICP-MS) in bioassay measurements could improve the measurement

speed by about 3 orders of magnitude at the lower limit of detection currently

achievable with alpha spectrometry for long-lived radionuclides. To check this the

capability and efficiency of ICP-MS technology for the determination of uranium

in urine samples has been examined. The results show that Sector Field ICP-MS

in low-resolution mode allows highly sensitive uranium determination in human

urine samples to the physiological level of


25/7123

The in-vivo monitoring work package of the project aims to improve measure-

ments and calibration techniques, to reduce the systematic errors and to achieve

higher accuracy in activity calculation and intake and effective dose evaluation.The intention is to combine expertise in optimized and developed in-vivo mea-

surement techniques with newly developed calibration methods and with the

latest biokinetic modelling. The work completed to date includes the assess-

ment of the potential of the reconstruction of numerical phantoms using ana-

tomical and physiological data relating to individuals to be measured, with the

longer-term goal of flexible use in a large number of different applications such

as whole body counting and measurement of the lung. This involves an original

calibration method that has been developed, combining the creation of numeri-

cal phantoms in the form of voxels obtained from tomographic images (CT) or

magnetic resonance images (MRI) with Monte Carlo calculations. It involves the

use of a graphical user interface (Anthropo) specially developed with the PV-

Wave software suite. The Monte Carlo code used is MCNP4c, which simulates

the transport of photons with energies corresponding to the range of interest

(i.e. 10 to 1400 keV) through tissue.

The demonstration of Anthropo abilities for the study of uncertainties for in-vivo

calibrations consists of two fields of investigation:

1. Lung measurements, for which two types of experiments and calculations were

performed. First, the agreement between real measurement and mathematical

simulation results was investigated. Secondly, the dependence of simulated

results on variation of phantom geometries was demonstrated.

2. Whole body counting for which the current status of the work is the creation

of the voxel phantoms of IGOR phantom (6 sizes) and the validation of ex-

perimental results with simulations.

The results of the application of the methods described for lung counting are

shown in Figure 1.

Figure 1: The calculated relative difference for the counting effi ciency in the full

absorption peaks of 235U and 241Am for different phantoms, normalized to the

simulation data for the patient and processed with Anthropo, as a function of

peak energy

Project Information

Title:

Dosimetry Enhancements

in Application

Acronym: IDEA

Co-ordinator:

Christian Schmitzer

ARC Seibersdorf research

AT-2444 Seibersdorf

Austria

Tel.: +43 50550 2500

Fax: +43 50550 2502


Partners:

W. Wahl, P. Roth, GSF Munich,

Germany

D. Franck, L. deCarlan, IRSN Paris,

France

A. Andrasi, P. Zombori, AEKI Buda-

pest, Hungary

C. Schmitzer, A. Brandl, ARCS

Seibersdorf, Austria


Henning von Maravic

Tel.: +32 2 296 52 73

Fax: +32 2 295 49 91


Period Programme:


Status: Completed

Courtesy ARC


26/7124

Other work focussed on biokinetic modelling of natural radionuclides. In-vivo

measurements were performed periodically since 1998 on a family whose radio-nuclide uptake comes only from the drinking water of their private well from

1983 to the end of 2002. The time dependent variation of the concentration of

natural radionuclides in water and the approximate personal water consumption

were obtained from interviews. The modelling time points are chosen for each

member according to the year of birth, the year the well was built (in 1983),

the age and daily water intake, the year of source measurement, the ICRP age

groups and f1-values. The ICRP biokinetic compartment model of uranium in

man was adopted in this study and the transfer rates were taken from ICRP 69.

Some of the results obtained by these investigations are shown in Figure 2.

Figure 2: The cumulative uranium exposure as an example for the child.

DIJME

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IDEA


27/7125

Partnership

The particular advantages of this project were that it brought together partnerswith complementary experience. The ARCS department of radiation protection

has more than 20 years of experience in internal and external dosimetry, both

research and services. The GSF-ISS has more than 30 years experience in incor-

poration monitoring both by direct measurements applying whole body and par-

tial body counters as well as bio-assay techniques using ICP-MS. The IRSN labo-

ratory in charge of this programme has gathered experience and skills in major

areas of internal dosimetry, in particular: aerosol characterisation at workplaces,

biokinetics of radionuclides, bio-assay analysis and in-vivo measurements, and

microanalysis. FinallyAEKI Health Physics Department is the leading Hungarian

institution at the Atomic Energy Research Institute focusing inter alia on whole

body counting. In the field of internal dosimetry, the institute has participated

in numerous intercomparison exercises.

Selected references

Schmitzer, C., Brandl, A., Wahl, W., Roth, P., Franck, D., de Carlan, L., and A. Andrasi: Develop-

ments in Internal Monitoring Techniques, Rad. Prot. Dosim. Vol. 105, No. 1-4, 451-456 (2003);invited paper at the Workshop on Internal Dosimetry of Radionuclides, Oxford, 2002.

Wahl, W., Haninger, T., Kucheida, D., Roth, P., and H.G. Paretzke: Study of long-term radonprogeny in humans for retrospective evaluation of radon exposure, Journal of Radioanalyticaland Nuclear Chemistry, Vol. 243, No.2, 447-450 (2000).

Franck, D., Borissov, N., de Carlan, L., Gnicot, J.L., and G. Etherington: Application of MonteCarlo calculations to the evaluation of uncertainties in the assessment of lung activity, Rad.

Prot. Dosim. Vol. 105, No. 1-4, 403-408 (2003).

Bagatti, D., Cantone, M.C., Giussani, A., Veronese, I., Roth, P., Werner, E., and V. Hollriegl:Regional Dependence of Urinary Uranium Baseline Levels in Non-exposed Subjects with Par-ticular Reference to Volunteers from Northern Italy, J. Environ. Radioact, 65, 357-64 (2003).


28/7126

Biokinetics and Dosimetryof Internal Contamination BIODOS


This work is aimed at providing a substantial body of new information on ra-dionuclide behaviour in the human body and new or improved approaches to

biokinetic modelling. This should lead to improved confidence in the calculation

of radiation doses, and the assessment of risks following accidental or environ-

mental intake of radionuclides, by workers or members of the public, including

young children.

Achievements

BIODOS consists of a large number of complementary parallel studies, and many

have not yet reached the stage of producing results from which conclusions canbe drawn. Among the studies, the most important are:

The production of new information on the biokinetics of Mo, Co, Zr and

Ru in humans, animal data on doses to sensitive cells in the gut from

ingested radionuclides, in vitro data on U, speciation in the gut, and in

vitro data on cellular deposition of energy from short-range emitters. All

these data have been or will be integrated in new models.

The revision of the current ICRP model of the human alimentary tract (to

be completed in June 2004). This new model is designated to be appli-

cable to children as well as adults and describes absorption, secretion

and retention in different regions including the mouth and oesophagus,uses recent data for transit times through the regions and reconsiders

the estimation of dose to sensitive cells in each region.

The development of new models for the transfer of radionuclides to

breast milk and for the interpretation of bioassay data and calculation

of dose coefficients. This includes reviewing published data on radionu-

clides biokinetics in breast milk and systemic compartment. New models

and dose coefficients are now available for H, C, S, Ca, Fe, Co, Ni, Zn, Se,

Sr, Zr, Nb, Mo, Ru, Ag, Sb, Te, I, Cs, Ba, Ce, Pb, Po, Ra, Th, U, Np, Pu, Am,

Cm and have been or will be published in the open literature.

The delivery of many data aimed at improving the Human Respiratory

Tract Model of the ICRP. This includes:

The measurement of regional deposition and clearance of ultrafine

particles (UFP) in human volunteers; the modelling of total, regional

and local deposition of UFP at different levels of the human respira-

tory tract: and the modelling of UFP transport and deposition in bron-

chial airway bifurcations and alveoli by numerical techniques.

The development of a model of asymmetric and asynchronous ventila-

tion in healthy and diseased human lungs, the calculation of particle

deposition in healthy and diseased lungs, and the study of bronchialand bronchiolar clearance in smokers, patients and elderly persons.

ObjectivesThe radiation doses received by indi-

viduals from radionuclides which enter

the human body cannot be measured

but must be calculated. Assessments

of doses and risks to workers exposed

to radionuclides and to the public fol-

lowing environmental releases require

biokinetic models which describe the

behaviour of the radionuclides from

their entry into the body until their final

elimination. The overall objective of this

project is to improve the scientific basis

of the existing models and to provide

new or improved models. Realistic and

scientifically sound estimates of the

doses received in different situations

will be given, as well as assessments

of the uncertainties in these estimates.

The project combines established ex-

perimental and mathematical modelling

expertise, including human, animal and

in vitro studies.

The work comprises two parts focused

respectively on the delivery of new sys-

temic, digestive tract and breast-milk

models and on the improvement of the

human respiratory tract model of the In-

ternational Commission on Radiological

Protection (ICRP).


29/7127

The description of the effect of particle size on clearance; the effect

of specific surface area on dissolution and absorption from different

respiratory tract regions; using combinations of in vitro experimentsand in vivo studies with rodents and human volunteers.

The description of the role of alveolar macrophages in particle trans-

port and dissolution, investigating mucociliary clearance (the main

mechanism of rapid bronchial particle clearance) and modelling par-

ticle clearance within bronchial airway bifurcations.

The delivery of specific data describing the importance, in terms of

dosimetry, of heterogeneous distribution of dose within tissues and cells.

Partnership

The project has involved state of the art research by a consortium of 15 organi-

sations from 9 countries. Each organization has various competences, which are

used in a complementary way. This wide participation contributes to consolidate

and advance European knowledge and competence in the radiological sciences.

Project Information

Title:Biokinetics and dosimetry of internalcontamination

Acronym: BIODOS

Co-ordinator:Franois PaquetIRSN, Laboratoire de radiotoxicologieexprimentaleB.P. 166FR-26702 Pierrelatte CedexFranceTel.: + 33 4 75 50 43 81Fax: + 33 4 75 50 43 26


Partners: F. Paquet (Institut de Protection et de

Sret Nuclaire, Pierrelatte, France) W. Hofmann (Universitaet Salzburg, Austria) M. Bailey (National Radiological

Protection Board, Chilton, Didcot, UK) I. Balashazy (Technoorg-Linda Co .

Ltd., Budapest, Hungary) M. Svartengren (Karolinska Institutet,

Stockholm, Sweden) R. Falk (Swedish Radiation Protec-

tion Institute, Stockholm, Sweden) J.L. Poncy (Commissariat lEnergie

Atomique, Bruyres le Chtel, France) P. Roth, (Forschungszentrum fuer Umwelt

und Gesundheit, Neuherberg, Germany) G. Scheuch (Institut fr Aerosol-Medizin,

Gauting, Germany) D. Nosske, Bundesamt fuer

Strahlenschutz, Munich, Germany) M.C Cantone (Universita degli Studi

di Milano, Milan, Italy) D.M. Taylor (University of Wales,

Cardiff (UWC) R. Kriehuber (University of Rostock,

Germany) F. Schultz (Delft University of

Technology, Delft, NL) M. Frenz (University of Berne, Switzerland)

EC Scientific Officer:Henning von MaravicTel.: +32 2 296 52 73Fax: +32 2 295 49 91E-mail: [email protected]

Period Programme:Nuclear Energy 1998-2002

Status: Completed

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30/7128

Radionuclides BiokineticsDatabase (EULEP) RBDATA-EULEP


A large number of studies have been carried out of the behaviour of radionu-clides in the body (biokinetics) following administration to laboratory animals.

Many were conducted during the period of rapid expansion of nuclear indus-

tries, because of concerns about exposures of workers, and the difficulties of

evaluating doses from such exposures. There is a continuing need to use the

results of these studies for the development of more realistic models to describe

human radionuclide biokinetics, and their application in new areas of concern,

such as decommissioning and deliberate releases of radioactivity. Many detailed

results are in laboratory reports which might not be found by on-line searches,

and many of the scientists who conducted the studies have retired, or will do

soon. Considerable effort is therefore required to assemble all the information

relevant to a particular material, and it is important to compile as much informa-

tion as possible at this time.

Achievements

An existing electronic database developed by members of EULEP (European Late

effects Project Group) during the Fourth Framework Programme (199799) was

enhanced and extended for use here. The electronic format facilitates extension,

updating, and information retrieval. It consists of a table of References linked to

three tables of Experiments, one for each route of intake: Inhalation, Ingestion

and Injection. The References table contains information about each Reference: cita-

tion details, abstract, and comments e.g., whether it is a review, con-

tains original data, etc.

Each table of Experiments summarises information on each experiment,

in three sections, which give information and comments on the material

studied, experimental methods and results. The results can be linked to

spreadsheets.

ObjectivesThe overall aim of this Concerted Action

is to provide information to improve the

assessment of doses from intakes of

radionuclides by workers and the pub-

lic. The main objectives are to review

the scientific literature on relevant ex-

perimental studies, and to summarise

important information in an electronic

database. Further objectives are to pro-

vide easy access to the database via the

Internet, and to transfer expertise on

methodology by organising small train-

ing workshops for young scientists.


31/7129

Data entry is facilitated by using drop-down lists wherever possible for fre-

quently used terms (elements, chemical forms, species, etc.). The information

is automatically organised because it is entered in specific fields. Informationcan be retrieved in various ways. From the main menu, searches can be carried

out to find all experiments relating to a route of intake, for a given element and

chemical form. Alternatively, a search can be made for all references involving

a chosen author. Clicking a button on the form that displays the information

about a reference gives lists of experiments linked to the reference. Similarly,

a button on the form that displays the information about an experiment lists

all the publications that refer to it. Although the database was designed with

radionuclide biokinetics in mind, a similar database structure could be used to

store and retrieve information about any type of experiment. At the start of the

project, the database contained information on about 300 experiments: enough

only to demonstrate its potential usefulness. This has increased to about 1500

experiments (from over 500 publications) representing 61 elements, although

more than half relate to uranium, plutonium, or cobalt.

Data entry will continue, and it is also planned to provide access to the data-

base via the Internet, to enable scientists in the field and radiation protection

professionals to search for and extract information quickly and easily. A draft

web site has been developed that enables users to view information in the da-

tabase using a web browser. However, further features need to be implemented

before it is suitable for wider use.

It is envisaged that there are three main potential types of direct users of the

database, who would all benefit from simple and rapid access to the existing

information:

Groups of experts involved in developing guidance or standards relating

to exposure to radioactive materials.

Scientists involved in research on radionuclide biokinetics. It will facilitate

the design of further experiments, and avoid unnecessary repetition.

Health physicists who need to assess the consequences of accidental

intakes.

Two short workshops have been held: on inhalation of radioactive materials,and on in vitro dissolution and aerosol characterisation. Broader courses on

experimental techniques and interpretation of experimental data are planned.

Project Information

Title:

Radionuclides Biokinetics Database

(EULEP)

Acronym: RBDATA-EULEP

Co-ordinator:

Michael Bailey

National Radiological Protection Board,

NRPB

UK-OX11 0RQ Chilton

United Kingdom

Tel.: +44 1235 831600

Fax: +44 1235 833891E-mail: [email protected]

Partners:

V. Chazel (Institut de Radioprotection

et de Sret Nuclaire, IRSN,

Pierrelatte, France)

P. Fritsch (Commissariat lEnergie

Atomique, CEA, Bruyres-le-Chtel,

France)

W. Kreyling (GSF Forschungszentrum

fr Umwelt and Gesundheit, GmbH,

GSF, Neuherberg/Munich, Germany)

D. Newton (AEA Technology, AEAT,

Harwell, UK)

D. Taylor (University of Wales, UWC,

Cardiff, UK)

M. Svartengren (Karolinska Institute,

KI, Stockholm, Sweden)


Neale KellyTel.: +32 2 295 64 84

Fax: +32 2 295 49 91


Period Programme:


Status: Completed


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33/7131

Radionuclides biokinetics database: data entry screen for publications.

Radionuclides biokinetics database: data entry screen for injection experiments.

Courtesy NRPB

Courtesy NRPB


34/7132

Optimisation of Monitoringfor Internal Exposure OMINEX


Current internal dose monitoring practice needs to be considered when develop-ing advice on improved methods. However, there was a lack of available informa-

tion on current practice in different countries across the EU. A major task in the

early stages of the project was therefore to carry out a comprehensive survey.

In developing advice, a number of novel approaches needed to be developed

and implemented. Optimisation of in vitro and in vivo measurements required

methods to be developed first to quantify total uncertainty on the measured

quantities, and then to optimise the measurement parameters themselves. In

developing advice on the design of monitoring programmes, the intention was

to improve on existing approaches by making full use of material specific data

rather than default values, to include consideration of variability or uncertainty

in human biokinetic parameter values, and to develop a methodology for the

assessment of total uncertainty in assessed intakes and doses.

Achievements

The OMINEX project is now nearing completion. Results of the project were

presented at a Training Course held at La Dfense, Paris on 24-25 November

2003. The course was very well attended, with over eighty registrations. All of

the lectures will be collected on a single CD-ROM, enabling the course to be

repeated if there is sufficient demand.

Advice has been developed for monitoring following exposures to tritium, cobalt,

iodine, caesium, uranium, thorium and plutonium. However, only a few examples

of the results of the project can be described in this brochure (see below). A full

account can be found in the reports that have already been issued, or are in

preparation; an up-to-date list of references can be provided by the Scientific

Coordinator. Preliminary results were described in several papers presented at the

Workshop on Internal Dosimetry, held at New College, Oxford in September, 2002.

A full list of references to these papers is given in Etherington et al.1

Responses to surveys on internal dose monitoring programmes and costs

were received from organisations in the UK, Nordic countries, Austria, Belgium,

France, Germany, Spain, Czech Republic, Hungary, Russia and other former states

of the USSR. Information was collected on general aspects of monitoring such

as type of operation, number of workers, monitoring practice and purposes of

monitoring; on methods of monitoring of fission and activation products and

actinides (uranium, thorium, plutonium, americium and mixed oxide (MOX) fuel);

on calibrations and minimum detectable amounts; on chemical forms; and on

monitoring frequency and investigation levels. Results have been compiled in

an MS AccessTM database.

Objectives

The primary aim of the OMINEX project

is to provide advice and guidance on

the design and implementation of inter-

nal dose monitoring programmes in the

workplace. The target audience includes

dosimetry service managers, regulators

and senior medical staff in the nuclear

industry. Advice has been developed

on internal dose monitoring following

exposure to a range of radionuclides

and compounds that are of the most in-

terest, and that represent some of the

most difficult problems in internal dose

assessment. Topics considered include

choice of monitoring method(s), (e.g.

excretion (in vitro) monitoring vs. whole

body or lung (in vivo) monitoring),

choice of measurement technique (e.g.

alpha spectrometry vs. mass spectrom-

etry), monitoring intervals, measure-

ment frequency, required measurement

sensitivity and accuracy, and measure-

ment parameters needed to achieve this

performance (detection efficiency, count

times, etc.). The economic costs of moni-

toring and control of internal exposures

in the workplace are usually signifi-

cantly greater than the equivalent costs

for external exposures. The underlying

approach to optimisation was therefore

to evaluate costs versus benefits, the

latter being quantified primarily by as-

sessing the sensitivity or accuracy with

which intakes and doses are determined

from the results of particular monitoring

methods.


35/7133

The work carried out on optimisation of urine and faecal bioassay measurement

parameters2 included consideration of sample volume, tracer activity, counting

efficiency, background levels, sample and background counting times and chem-ical yield. Figure 1 shows the measurement uncertainties that would be achieved

using the recommended values for these parameters for alpha spectrometric

measurements of plutonium in urine.

The methodology developed to assess total uncertainty in assessed intakes

and doses takes account of uncertainties in intake patterns, uncertainties in

respiratory tract model parameters such as absorption parameters and particle

size, and uncertainties in parameters describing retention of the radionuclide

in organs of the body following uptake. The method was first implemented

for the simple case of routine tritium-in-urine monitoring. Figure 2 shows how

uncertainty in the assessed dose increases as the routine monitoring interval

increases from 7 to 90 days.

A systematic approach to the development of advice on internal dose monitor-

ing following exposure to industrial actinide-bearing materials was developed.

In the case of monitoring for exposures to uranium compounds 3, occupational

exposure standards based on chemical toxicity were reviewed; material-specific

biokinetic data were reviewed; limits on intake were evaluated; the most ap-

propriate methods for assessment of intake were discussed; advice on monitor-

ing intervals/periods for routine and special monitoring were provided; and the

circumstances when chemical toxicity rather than radiation dose is the limiting

factor were investigated. Table 1 shows recommended routine monitoring inter-

vals for specified uranium compounds.

Partnership

OMINEX was conceived as a collaboration between research/advisory organisa-

tions (IRSN, NRPB, SCKCEN, STUK) and industry (EdF, TVONS, CEA), and this

has ensured that the results of the project are practicable, and relevant to the

needs of industry. The participation of major organisations from a number of EU

countries has promoted the development of a common approach to the issue of

design of internal dose monitoring programmes.

Selected references

Etherington G, Stradling G N, Rahola T, Le Guen B, Hurtgen C, Jourdain J-R and Brard P.:Design and implementation of monitoring programmes for internal exposure (ProjectOMINEX) Radiat. Prot. Dosim, 105, 641-644 (2003).

Hurtgen C, and Cossonnet C.: A survey on uncertainty in bioassay measurements carriedout within the OMINEX project. ibid., 375-378.

Stradling N, Hodgson A, Ansoborlo E, Brard P, Etherington G, Fell T and Le Guen B.:

Optimising monitoring regimens for uranium oxides after chronic inhalation by workers.ibid., 109-114.

Project Information

Title:

Optimisation of Monitoring for Internal

Exposure

Acronym: OMINEX

Co-ordinator:

George Etherington

National Radiological Protection Board

Chilton

Didcot

UK-OX11 0RQ Oxon

United Kingdom

Tel.: +44 1235 822658Fax: +44 1235 833891


Partners:

C. Cossonnet, IRSN, Fontenay-aux-

Roses, France

G. Etherington, NRPB, Chilton, UK

D. Franck, IRSN, Fontenay-aux-Roses,

France

J.-L. Genicot, SCKCEN, Mol, Belgium

C. Hurtgen, SCKCEN, Mol, Belgium

J.-R. Jourdain, IRSN, Fontenay-aux-

Roses, France

B. Le Guen, EdF, Saint Denis, France

T. Rahola, STUK, Helsinki, Finland

J. Sovijrvi, TVONS, Olkiluoto, Finland

G. N Stradling, NRPB, Chilton, UK


Neale Kelly

Tel.: +32 2 295 64 84Fax: +32 2 295 49 91


Period Programme:


Status: Completed


36/7134

Figure 1: Measurement uncertainty as a function of measured Pu- activity in urine

Figure 2: Probability distribution functions describing total uncertainty in effective

dose (E50) assessed from tritium-in-urine measurements, for the specified routine

monitoring intervals

.FBTVSFEBDUJWJUZN#RE

EBZT

EBZT

EBZT

EBZT

'SFRVFODZ

"TTFTTFEEPTF5SVFEPTF

OMINEX

Courtesy NRPB

Courtesy NRPB


37/7135

Table 1: Recommended routine monitoring intervals for chronic inhalation

of the specified compounds

Compound Lung Urine Faeces

Uranium nitrate

Uranium tributylphosphate No 30 d No

Uranium peroxide

Ammonium diuranate 180 d 90 d 180 d

Uranium trioxide

Uranium tetrafluoride 180 d 90 d 180 d

Uranium octoxide 180 d 90 d 180 d

Uranium dioxide

Courtesy NRPB


38/71


39/71

Section 2External Exposure


40/7138

Evaluation of Individual Dosimetry in MixedNeutron and Photon Radiation Fields EVIDOS


The readings of dosemeters observed under specific exposure conditions in aworkplace

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