IDEAS General Guidelines for the Assessment of Internal

IM2005, Vienna, April 2005 1

General Guidelines for the Assessment of Internal Dose from Monitoring Data (Project IDEAS)

H. Doerfel, FZK, KarlsruheA Andrasi, KFKI, Hungary

M Bailey, J Marsh, J Stather, NRPB, UKV Berkovski, RPI, Ukraine

C-M Castellani, ENEA, ItalyC Hurtgen, SCK•CEN, Belgium

J-R Jourdain, E Blanchardon, I Laniece, IRSN, FranceB LeGuen, EDF, France

I Malatova, RPI Czech Rep. (corresponding member)R Cruz-Suarez, J Zeger, IAEA (corresponding members)

IDEAS


Background

Monitoring data

Assumptions:•Pathway of intake•Time course of intake•Biokinetic Model(s)•Parameter values for material & subject

Assumptions:•Pathway of intake•Time course of intake•Biokinetic Model(s)•Parameter values for material & subject

Influencing factors:•Amount and quality of data•Skill and experience of the dosimetrist•Computational tools available

Influencing factors:•Amount and quality of data•Skill and experience of the dosimetrist•Computational tools available

Intake & Committed Dose

General experience:When a set of bioassay data is given to two different assessors, it is likely that different assumptions will be made, and perhaps different methods applied and therefore that different results will be obtained.

General experience:When a set of bioassay data is given to two different assessors, it is likely that different assumptions will be made, and perhaps different methods applied and therefore that different results will be obtained.

General guidelines for the estimation of committed dosefrom incorporation monitoring data

(Project IDEAS)IDEAS


What we have learned from recent intercomparison exercises

There is a clear need to develop guidelines on assessments of intake and internal doses, in order to promote harmonisation in assessments, especially, but not only, across the EU.

Such guidelines have formed the core of the IDEAS project.




Presentation to Intercomparison Workshop 18 April 2005

1: The IDEAS Project

2: The IDEAS guidelines




Cost-shared action in 5th FP42 Months: October 2001 – March 2005(extended to June 2005, to co-ordinate intercomparison exercisewith IAEA and this Workshop with IM 2005)

Cost-shared action in 5th FP42 Months: October 2001 – March 2005(extended to June 2005, to co-ordinate intercomparison exercisewith IAEA and this Workshop with IM 2005)

The project:



The aims:

To develop guidelines to standardise assessments of internaldoses

To develop guidelines to standardise assessments of internaldoses

By application of such guidelines, different assessors shouldobtain the same result from the same data

By application of such guidelines, different assessors shouldobtain the same result from the same data


Work package 1Collection of

incorporation cases(C. Hurtgen)

Survey of open literatureSurvey of open literature

Contacts with industry and research institutionsContacts with industry and research institutions

Selection of cases for assessment by consortium(WP3)

Selection of cases for assessment by consortium(WP3)



Bibliographic database•Compilation of references (author, year, title, journal)•Content: 547 references (mainly Health Phys. (229), Rad. Prot. Dos. (60))

Bibliographic database•Compilation of references (author, year, title, journal)•Content: 547 references (mainly Health Phys. (229), Rad. Prot. Dos. (60))

Incorporation case database•Detailed information (case description, monitoringresults, dose assessment)•Content: 209 cases

Incorporation case database•Detailed information (case description, monitoringresults, dose assessment)•Content: 209 cases



incorporation cases

Work package 2Preparation of

evaluation software(V. Berkovski)

Investigate improved mathematical methods to assess intakes from monitoring data

Investigate improved mathematical methods to assess intakes from monitoring data

Implement in existing software (IMIE: RPI)

Implement in existing software (IMIE: RPI)



Implementation of new features:• Mixed fractions of pathway of intake (inhalation, ingestion, injection)• Mixed fractions of absorption types (F, M and S)• Wound simulated as chronic injection and/or multiple injection• AMADs up to 20 micron• Import of individual retention and excretion functions

Implementation of new features:• Mixed fractions of pathway of intake (inhalation, ingestion, injection)• Mixed fractions of absorption types (F, M and S)• Wound simulated as chronic injection and/or multiple injection• AMADs up to 20 micron• Import of individual retention and excretion functions



incorporation cases


evaluation software

Work package 3Evaluation of

incorporation cases(C-M. Castellani)

Identification of factors and assumptions for whichguidance is needed

Identification of factors and assumptions for whichguidance is needed



•Evaluation of 52 cases (29 of them by 2 or more evaluators) •Application of both IMIE and IMBA ExpertTM

•Selection of the best estimates•Identification of important issues related to the guidelines

•Evaluation of 52 cases (29 of them by 2 or more evaluators) •Application of both IMIE and IMBA ExpertTM

•Selection of the best estimates•Identification of important issues related to the guidelines

Evaluation database•Compilation of all information (Word and Excel files)•Content: 95 independent evaluations of 52 cases

Evaluation database•Compilation of all information (Word and Excel files)•Content: 95 independent evaluations of 52 cases



incorporation cases


evaluation software


incorporation cases

Work package 4Development of

general guidelines(H. Doerfel)

Develop common approach for evaluation of monitoring data

Develop common approach for evaluation of monitoring data

Consider data handling (intake pattern, multiple data sets, errors, rogue data etc.)

Consider data handling (intake pattern, multiple data sets, errors, rogue data etc.)

Discuss with experts in open „Virtual“Workshop (1) on the Internet

Discuss with experts in open „Virtual“Workshop (1) on the Internet

Develop draft guidelines based on Workshop discussions

Develop draft guidelines based on Workshop discussions

Prepare report on draft guidelinesPrepare report on draft guidelines




Work package 4 (Development of general guidelines)



Details and discussion in Part 2 of presentation

(later)

Details and discussion in Part 2 of presentation

(later)


Special webpage (www.ideas-workshop.de) for posting the guidelinesSpecial webpage (www.ideas-workshop.de) for posting the guidelines

Virtual workshop for discussion of the guidelines with the community



Discussion forum for every stage of the guidelines where anyone could place his (orher) comments

Discussion forum for every stage of the guidelines where anyone could place his (orher) comments

Start of the workshop on 31 May 2004; end is still openStart of the workshop on 31 May 2004; end is still open

Announcement of the workshop through contacts, relevant national and international organisations etc. (including IRPA Madrid)

Announcement of the workshop through contacts, relevant national and international organisations etc. (including IRPA Madrid)


Statistics of the visits of the website (www.ideas-workshop.de) Statistics of the visits of the website (www.ideas-workshop.de)




Month Number of Visits

May 2004 188

June 2004 1140

July 2004 237

August 2004 209

September 2004 205


Statistics of the visits of the discussion forumStatistics of the visits of the discussion forum




Stage Subject Visits Comments1 First check of data 207 102 Check of statistical

significance134 8

3 Standard procedure 109 34 Special procedure –

definition of pathways101 0

5 (5.1 – 5.3) Special procedure forinhalation

366 16

6 (6.1 – 6.3) Special procedure foringestion

238 2

7 (7.1 – 7.3) Special procedure forinhalation and ingestion

116 1

Total 1271 40


Special webpage (www.ideas-workshop.de) for posting the guidelinesSpecial webpage (www.ideas-workshop.de) for posting the guidelines




Start of the workshop on 31 May 2004; end is still open,Continuation, linked to CONRAD FP6 Project (Carlo-Maria Castellani & Hans Doerfel)

Start of the workshop on 31 May 2004; end is still open,Continuation, linked to CONRAD FP6 Project (Carlo-Maria Castellani & Hans Doerfel)

Information exchange for internal dosimetry communityInformation exchange for internal dosimetry community

Develop guidelines furtherDevelop guidelines further



incorporation cases


evaluation software


incorporation cases

Work package 4Development of

general guidelines

Work package 5Practical testing

of general guidelines

Organise Joint Intercomparison Exercise on Internal Dose Assessment together with IAEA•Prepare, distribute cases & guidelines•Compile results

Organise Joint Intercomparison Exercise on Internal Dose Assessment together with IAEA•Prepare, distribute cases & guidelines•Compile results

Workshop (2) with participants to discuss results

Workshop (2) with participants to discuss results

Modify draft guidelines according to results of discussion

Modify draft guidelines according to results of discussion

Publish report and General GuidelinesPublish report and General Guidelines




General philosophybased on the evaluation (Work package 3)

General philosophybased on the evaluation (Work package 3)

Work package 4 (Development of general guidelines)



Levels of taskbased on general philosophy

Levels of taskbased on general philosophy

General guidelines for the evaluationbased on „Level of task“ structure

General guidelines for the evaluationbased on „Level of task“ structure


Harmonisation:by following the procedures any two assessors should obtain the same estimate of dose from a given data set

Harmonisation:by following the procedures any two assessors should obtain the same estimate of dose from a given data set

General philosophy



Best estimate:the “best” estimate of dose should be obtained from the available data

Best estimate:the “best” estimate of dose should be obtained from the available data

Proportionality:the effort applied to the evaluation should be proportionate to the dose – the lower the dose, the simpler the process should be.

Proportionality:the effort applied to the evaluation should be proportionate to the dose – the lower the dose, the simpler the process should be.

Discussion point?

Sometimes there is conflict between these principles. Which has priority?


The general guidelines provide


(Project IDEAS)IDEAS•processing of data before use,•handling of single data and multiple data sets,•number and type of data required for the dose assessment•assessment of the uncertainty on data, •handling of data below the limits of detection, •handling of data influenced by chelation therapy •and the identification of rogue data

•processing of data before use,•handling of single data and multiple data sets,•number and type of data required for the dose assessment•assessment of the uncertainty on data, •handling of data below the limits of detection, •handling of data influenced by chelation therapy •and the identification of rogue data

Detailed information about data handlingDetailed information about data handling

General information about the evaluation of the monitoring data reflecting the general philosophy

General information about the evaluation of the monitoring data reflecting the general philosophy

Structured approach to the dose assessment reflecting the levels of task.Structured approach to the dose assessment reflecting the levels of task.


Level 0: Annual dose < 0.1 mSv No evaluation of dose needed. (German & Swiss Guidelines, external doses rounded)

Level 0: Annual dose < 0.1 mSv No evaluation of dose needed. (German & Swiss Guidelines, external doses rounded)

Levels of task



Level 1: Dose from the intake typically 0.1 – 1 mSvSimple, “reference” evaluation, with ICRP defaults used for all parameter values, except where there is better a priori information available

Level 1: Dose from the intake typically 0.1 – 1 mSvSimple, “reference” evaluation, with ICRP defaults used for all parameter values, except where there is better a priori information available

Level 2: Dose from the intake typically 1 – 6 mSvSophisticated evaluation using additional information to give more realistic assessment of dose: Adjustment of AMAD, absorption type or the time of intake if unknown (A posteriori: using measurement data)

Level 2: Dose from the intake typically 1 – 6 mSvSophisticated evaluation using additional information to give more realistic assessment of dose: Adjustment of AMAD, absorption type or the time of intake if unknown (A posteriori: using measurement data)

Level 3: Dose from the intake typically > 6 mSvMore sophisticated evaluation, which applies to cases where there are comprehensive data available: Systematic adjustment of the model parameter values (“step-by-step”approach), until the fit is acceptable (not rejected)

Level 3: Dose from the intake typically > 6 mSvMore sophisticated evaluation, which applies to cases where there are comprehensive data available: Systematic adjustment of the model parameter values (“step-by-step”approach), until the fit is acceptable (not rejected)


Stage 1 (Level 0)



Single routine measurement, M

Compare with tabulated value MC

If measurement M< MC implies “Annual dose”(committed effective dose from intakes in year) <0.1 mSv; assuming similar intakes in all monitoring intervals.

Record dose = 0.0 mSv. Record measurement. STOP

Single routine measurement, M

Compare with tabulated value MC

If measurement M< MC implies “Annual dose”(committed effective dose from intakes in year) <0.1 mSv; assuming similar intakes in all monitoring intervals.

Record dose = 0.0 mSv. Record measurement. STOP


Stage 1:Check of the need for evaluation


Structured approach to dose assessment


(Project IDEAS)IDEASStage

1

1.1Identify monitoring value M

1.2M < Mc(1)

1.2.1Level 0:

No evaluation neededEnd

Stage 2

yesno

1.3Above Level 0:

Evaluation needed


Stage 1 (Level 0) Step 1.1



Identify measurement (M) and duration of monitoring interval (T)

Data treatment (if needed)

Other radionuclides present as well as „Indicator“ thatwas measured?

Identify measurement (M) and duration of monitoring interval (T)

Data treatment (if needed)

Other radionuclides present as well as „Indicator“ thatwas measured?



(Project IDEAS)IDEASStage

1

1.1Identify monitoring value M

1.2M < Mc(1)

1.2.1Level 0:

No evaluation neededEnd

Stage 2

yesno

1.3Above Level 0:

Evaluation needed


Step 1.2: Example of the critical monitoring quantity Mc



Radionuclide Absorption

type (chemical

form)

Type of monitoring

Monitoring interval

(d)

Critical monitoring value MC

H-3

HTO

Urine

14 30 60

4400 Bq/d 5500 Bq/d 3900 Bq/d

Co-60

M

Whole body

90 180 360

160 Bq 230 Bq 290 Bq

Sr-90

F

Urine

90 180 360

0.4 Bq/d 0.2 Bq/d 0.2 Bq/d

I-131

F

Thyroid

7 14 30

18 Bq 26 Bq 26 Bq

Cs-137

F

Whole body

90 180 360

1200 Bq 1800 Bq 2000 Bq

U-235

S

Lungs

90 180 360

0.2 Bq < LLD 0.3 Bq < LLD 0.5 Bq < LLD

Pu-239

M

Urine

90 180 360

0.007 mBq/d < LLD0.011 mBq/d < LLD0.017 mBq/d < LLD


Stage 2 (Level 1)



Measurement M>MC

•Check whether M is significant:

•Need realistic estimate of uncertainty

•If so “reference” procedure (ICRP 78): Default

values, a priori parameter values, route of intake, etc.

•If “annual” dose <1 mSv (record dose) STOP

Measurement M>MC

•Check whether M is significant:

•Need realistic estimate of uncertainty

•If so “reference” procedure (ICRP 78): Default

values, a priori parameter values, route of intake, etc.

•If “annual” dose <1 mSv (record dose) STOP




Structured approach of the dose assessment



Stage 2:Check of the significance of measurement and consistency with previous evaluations


Stage 2

2.1Assessment of uncertainty on

measured value M (or application of default uncertainty)

2.2Calculation of contributions from

previous intakes (P)

2.3M > SF*P

Stage 3

2.4P/SF < M < P*SF End

2.3.1There is a new significant intake; calculation of net measured value

N = M - P

2.4.1There is no new significant intake

(confirmation of previous assessments)

2.5There is a discrepancy with previous

evaluations

2.6Value is reliable

2.7Make corrections on the measured value, if possible; otherwise repeat

measurement

2.6.1Special evaluation of

previous intakes needed

Stage 4

Yes

No

Yes

No

Yes

No


Stage 2 (Level >0) Step 2.1



Assess overall uncertainty on measurement:• New intake?•Consistent with previous intakes?•(Rogue point: inconsistent with other data?)•(Weighting in fitting more than one measurement)•(Objective criteria to determine whether model fitsdata) •(Objective criteria to choose between models)

Assess overall uncertainty on measurement:• New intake?•Consistent with previous intakes?•(Rogue point: inconsistent with other data?)•(Weighting in fitting more than one measurement)•(Objective criteria to determine whether model fitsdata) •(Objective criteria to choose between models)





Assess overall uncertainty on “measurement” for

comparison with model (Scattering Factor, SF):

•Type A (Poisson counting statistics) and Type B (other)

•Measurement of activity in sample (or in organs) and its

use to estimate modelled activity (e.g. daily excretion

rate), sampling errors, biological variability

Assess overall uncertainty on “measurement” for

comparison with model (Scattering Factor, SF):

•Type A (Poisson counting statistics) and Type B (other)

•Measurement of activity in sample (or in organs) and its

use to estimate modelled activity (e.g. daily excretion

rate), sampling errors, biological variability





Guidance on estimating SF:

•Log-normal. Not exact, but pragmatic (approximate

better than nothing, or only some contributions)

•Some details available for in vivo measurements

•General defaults (Table 2.3, Guthrie Miller) excretion

etc. based on plutonium.

Guidance on estimating SF:

•Log-normal. Not exact, but pragmatic (approximate

better than nothing, or only some contributions)

•Some details available for in vivo measurements

•General defaults (Table 2.3, Guthrie Miller) excretion

etc. based on plutonium.


Step 2.1: Default values for the components of log-normal uncertainty for various types of measurement

Quantity SF

true 24-hr urine 1.1simulated 24-hr urine, specific gravity normalization 1.3

spot urine sample 2.0

fecal sample 3 to 7

chest count 1.2 to 1.6

nasal swipe 3 to 7

room air monitor 7 to 20

Discussion point!!!•excretion etc. based on plutonium.

•Need more: typical SF for other radionuclides -

•contributions please!!!




Stage 2





2.3M > SF*P

Stage 3



N = M - P




evaluations



measurement



Stage 4

Yes

No

Yes

No

Yes

No

Discussion Point!

P/SF2<M<P*SF2

chance of false intakes or inconsistency >30%

Use eg SF2 ?




Stage 2





2.3M > SF*P

Stage 3



N = M - P




evaluations



measurement



Stage 4

Yes

No

Yes

No

Yes

No


Stage 3 (Level > 0) Standard evaluation



Measurement M due to new intake

•Confirm routine (not special, Stage 4)•Reference assumptions, as ICRP 78, eg. single intake(inhalation) at mid-point•Parameter values related to material (eg AMAD) ifknown before (a priori)

•If annual dose <1 mSv record and STOP

Measurement M due to new intake

•Confirm routine (not special, Stage 4)•Reference assumptions, as ICRP 78, eg. single intake(inhalation) at mid-point•Parameter values related to material (eg AMAD) ifknown before (a priori)

•If annual dose <1 mSv record and STOP









Stage 3:Standard „reference“ evaluation procedure


Stage 3

3.5Annual dose < 1 mSv

3.4Estimate intake and dose

End

Stage 4

3.2Assume pathway of intake

3.3Assign a priori parameters

(default or site-specific)

Yes

No

3.5.1Record intake and dose

3.1Routine monitoring?

No

Yes











Stage 4:Special evaluation procedure: Identification of pathway of intake

Stage 4:Special evaluation procedure: Identification of pathway of intake

Stage 4

4.1Pure inhalation?

Stage 5

Yes

No

4.1.1Special evaluation for inhalation

4.2Pure ingestion?

Stage 6

Yes4.2.1

Special evaluation for ingestion

4.3Inhalation and

ingestion?

Stage 7

Yes 4.3.1Special evaluation for inhalation and

ingestion

No

4.5.1The wound pathway not considered by the guidelines at the present state.

No

4.5Wound

involved?

No

Yes

4.4Injection or

skin absorption?

Stage 8

Yes4.4.1

Special evaluation for Injection

No

End




Stage 4

4.1Pure inhalation?

Stage 5

Yes

No

4.1.1Special evaluation for inhalation

4.2Pure ingestion?

Stage 6

Yes4.2.1

Special evaluation for ingestion

4.3Inhalation and

ingestion?

Stage 7

Yes 4.3.1Special evaluation for inhalation and

ingestion

No

4.5.1The wound pathway not considered by the guidelines at the present state.

No

4.5Wound

involved?

No

Yes

4.4Injection or

skin absorption?

Stage 8

Yes4.4.1

Special evaluation for Injection

No

End

Discussion point!

Understand the case:•Plot graph of data•Hand calculation?

Room air contamination(Default)

External contamination

Room air and external contamination AND justification

Stage 4: Special Assessment




Stage 5

5A (Steps 5.1 - 5.5)Initial assessment with a priori

parameter values

5B (Steps 5.7-5.14)Special evaluation for intake by

inhalation selecting AMAD, absorption Type and/or time of intake by comparison of model predictions

with data (a posteriori)

5.6Dose < 1 mSv End

Yes

No

5C (Steps 5.15-5.22)Stage 5C

Vary HRTM, HATM tract and systemic model parameter values in

specified order (a posteriori)

5.15Dose < 6 mSvand good Fit

EndYes

No

5.23Consult other experts

5.22.1Goodness of fit

is acceptableEnd

Yes

No

Stage 5: Special Assessment [Inhalation]Stage 5A: Initial evaluation using a priori parameters

Stage 5: Special Assessment [Inhalation]Stage 5A: Initial evaluation using a priori parameters

Stage 5B: Varying the AMAD, absorption type and/ortime of intake, if not known, using the data

Stage 5B: Varying the AMAD, absorption type and/ortime of intake, if not known, using the data

Stage 5C: Systematic adjustment of model parameters(HRTM, HAT) until fit is acceptable

Stage 5C: Systematic adjustment of model parameters(HRTM, HAT) until fit is acceptable




Stage 5A

5.1Identification of all measured data

representing the case

5.2Assessment of contributions from previous intakes and calculation of

net values of measured data

5.3Assign a priori parameters (default or site-specific)

5.5Calculate the dose with a priori

parameters

5.6Dose from intake

< 1 mSv

5.6.1Record dose with a priori parameters End

5.4Time of intake is known

No

Yes

Yes

Stage5B

No

5.6: If dose from intake <1 mSv,

•(for every measurement type)

•(for every radionuclide)

Record and STOP

Stage 5A: Special assessment

Inhalation: Standard evaluation

As Stage 3, but >1 measurement

5.4:

Routine measurement

•inconsistent with previous or

•standard evaluation, dose >1 mSv

5.5: Calculate intake (dose?) Ii from each measurement Mi

Best estimate = mean (Ii)




Stage 5B:

Special assessment Inhalation:

vary AMAD, F/M/S, Time of intake

5A

5.8Time of intake

is known

5.9Early lung and faeces

data available

5.10Derive effective AMAD from early

lung and faeces data

5.11Assessment of dose by fitting of the

absorption type

5.12Assessment of dose by simultaneous fitting of both the time of intake and

the absorption type

5.7.1Get additional dose relevant data

5.7There are suffcient

relevant data


is acceptable

5.13Assessment of dose by fitting of the mixture of default absorption types

(F,M,S)


the mixture of default absorption types (F,M,S)

5.12.3Record dose with all parameters


is acceptable

5.11.2Dose from intake

< 6 mSv

5.11.4Check the number of data required for evaluation at this level and get more

data, if necessary(Table)


< 6 mSv



No

No

Yes

No

Yes

No

Yes

Yes

NoYes

No

Yes

NoYes

No


Stage5B

Stage5CEnd End

Stages 5A & 5B: select parameter values by fitting model predictions to the data

Procedure stops when model fits, i.e. data do not reject model.

Easy if few data, hence steps 5.6, 5.11.4, 5.12.4:

Are there enough data ?

Depends on dose


Criteria for rejecting fit: Discussion Point!!!



Model should fit data for unbiased estimateProposed criteria for rejecting fit:•Chi-squared test statistic: 1% level if dose <6 mSv; 5% level if dose >6 mSv; OR•Fit looks unreasonable by eye (series of data under-or over-estimated.

Model should fit data for unbiased estimateProposed criteria for rejecting fit:•Chi-squared test statistic: 1% level if dose <6 mSv; 5% level if dose >6 mSv; OR•Fit looks unreasonable by eye (series of data under-or over-estimated.


Number and type of data needed for assessment of dosefor selected radionuclides and monitoring procedures

Required m onitoring data

D < 1 m Sv

1 m Sv < D < 6 m Sv

D > 6 m Sv

Radio- nuclide

Type of m onitoring

Num ber Tim e range

(days) Num ber Tim e range

(days) Num ber Tim e range

(days)

H-3 Urine 1 - 3 14 5 14

Co-60 W hole body 1 - 3 30 5 30

S r-90 Urine Faeces

1 - 3 30 3 3

30 30

Ag-110m I-125 I-131 Th yroid

Urine 1 - 3 7 3

3 7 7

Cs-137 W hole body 1 - 3 90 5 90

U-235 Urine Faeces Lungs

1 - 2 2 2

30 30 30

5 3 3

30 30 30

Pu-239 Urine Faeces

n.a. - 3 3

30 30

5 5

30 30

Am -241 Urine Faeces Lungs

Skeleton

1 - 2 2 2

30 30 30

3 3 3 1

30 30 30 30

Discussion point!!!

This is only a start (“place-holder”)

Help is needed to:

• confirm (or improve)

• extend to other situations

Hopefully workplace monitoring will ensure that sufficient data are available.




Stage 5B:


vary AMAD, F/M/S, Time of intake

5A

5.8Time of intake

is known

5.9Early lung and faeces

data available

5.10Derive effective AMAD from early

lung and faeces data

5.11Assessment of dose by fitting of the

absorption type


the absorption type

5.7.1Get additional dose relevant data

5.7There are suffcient

relevant data


is acceptable

5.13Assessment of dose by fitting of the mixture of default absorption types

(F,M,S)


the mixture of default absorption types (F,M,S)



is acceptable


< 6 mSv




< 6 mSv



No

No

Yes

No

Yes

No

Yes

Yes

NoYes

No

Yes

NoYes

No


Stage5B

Stage5CEnd End

Step 5.8 Procedure splits based on time of intake:

•known (5.9-5.13) or

•unknown (5.12, 5.14)




Stage 5B:


vary AMAD, F/M/S (Time of intake)

Step 5.8: time of intake known

Main effect of AMAD is partition between:

•upper respiratory tract (ET, BB, bb) mostly early fecal excretion

•lower respiratory tract (AI) mostly lung retention

Hence estimate “effective” AMAD




Stage 5B:



Main effect of AMAD is partition between:

•upper respiratory tract (ET, BB, bb) mostly early fecal excretion

•lower respiratory tract (AI) mostly lung retention

Hence estimate “effective” AMAD

0

2

4

6

8

10

12

14

0 1 2 3 4 5 6 7 8 9 10

AMAD, µm

Cum

ulat

ive

activ

ity in

faec

es fr

om 1

to 3

day

s /

activ

ity in

lung

on

day

3

Type M

Type S

Relatively insoluble materials

Ratio of early fecal excretion to lung retention (day 3) for Am-241

Could extend to other situations




Stage 5B:




Step 5.11 Fit absorption type

A priori assignment based on chemical form (Step 5.3)

Check “goodness” of fit (Step 5.11.1). If fit rejected try other Types (F/M/S)




Stage 5B: Special assessment Inhalation:



Steps 5.11.1&2 Model fits data, if dose <6 mSv record dose and stop.

Step 5.13 If fit rejected or additional data, try mixture of Types (F/M/S)

Steps 5.11.4 Enough data for 6 mSv?




Stage 5B: Special assessment Inhalation:

vary (AMAD), F/M/S Time of intake

Step 5.8: time of intake unknown

(Cannot determine “effective” AMAD)

Step 5.12 Simultaneous fit of time of intake and absorption.

If model fits data, and if dose <6 mSv record dose and stop.

Step 5.14 If fit rejected or additional data, try mixture of Types (F/M/S)

Step 5.12.4 Enough data for 6 mSv?

Discussion point!!!

If model fits, then probably several sets of parameter values (intake times and mixtures of absorption Types) will fit. Not straightforward to harmonise best fit with two variables. Needs more work.


Stage 5C: Advanced evaluation



Vary parameter values in order: check fit after each step

•HRTM absorption parameters (fr, sr, ss)

•GI tract absorption f1•HRTM particle transport parameters

•GI tract transit

•Systemic biokinetic model

Vary parameter values in order: check fit after each step

•HRTM absorption parameters (fr, sr, ss)

•GI tract absorption f1•HRTM particle transport parameters

•GI tract transit

•Systemic biokinetic model


Development of Guidelines

1. IDEAS: refine from outcome of the exercise, and discussions at the Workshop. Publish summer 2005.

2: ICRP Guidance Document to accompany revision of publications 30/54/68/78. Publish 2007?



3: IDEAS web site. CONRAD 2005-2007. FP7? Another exercise around 2007-8?

Documents

IDEAS General Guidelines for the Assessment of Internal