OCAS‐IG‐001

External Dose Reconstruct

Implementation Guidelin

Report from the Procedures Revie

Subcommittee

Presented to the

ABRWH Full Board Meeting

Augusta, Georgia

March 12, 2013
OCAS‐IG‐001 Summary

• Provides general (not specific) guidance 

the components, standards, and metho

be used to reconstruct external radiatiofor probability of causation (POC) calcu

• Detailed implementation guidance and 

information is provided in other site‐spor issue‐specific technical documents,procedures, and workbooks.
OCAS‐IG‐001 Timeline

• May 2002 – Revision 0 – Not Reviewed by SC&

• August 2002 – Revision 1

• January 17, 2005 – SC&A Review of Revision 1

• July 27, 2006 – Discussed with Subcommittee• August 25, 2006 – Revision 2

• October 29, 2007 – SC&A Review of Revision 2

• March 5, 2012 – Revision 3

• April 11, 2012 – SC&A to Review Revision 3 On

Determine which Findings were Closed

• February 5, 2013 – Discussed with Subcommitt

findings Closed
Findings Summary: OTIB‐00

• 24 Findings in total– complete histories captured in 

Review System (BRS)

– http://app‐cinc‐dcas.cdc.gov:8106/documents/default.aspx?mode

• Revision 1 – 17 Findings

• Revision 2 – 7 Findings• All 24 Findings are Closed• Resolution spanned 11 Years; May 2002 – February 2

• The following slides provide summary information o

resolution of each Finding – Details in BRS and hando
IG‐001, Rev 1 Review Findin

# Finding Resolution

1 Deficiencies with procedure layout

include: (1) fragmented structure,

(2) excessive amount of uselessdata and/or historical background

in main body, and (3) critical datafor dose reconstruction found in

Appendices rather that main body.

Closed on July 31, 2012

The Subcommittee determine

finding is Closed. Concerns ra

issue are covered in Finding 1

2 Guidance for deriving (1) film and

TLD dosimeter uncertainty, (2)

neutron dose from source term,and (3) occupational medical doseusing x‐ray machine operatingparameters requires data and

resources that are not available to

the dose reconstructor.

Closed on November 1, 2012

IG‐001 provides general princ

specific guidance. Detailed

implementation guidance and information are found in otheand procedures.
IG‐001, Rev 1 Review Findin

# Finding Resolution

3 IG‐001 provides inadequate

guidance for classifying a case

as potentially < 50% POC or >

50% POC and should identify

the role of Task 2 personnel.

Closed on July 27, 2006

IG‐001 is intended to provide gene

guidance. The level of detail suggecomment is not needed in this im

guide. This guidance is found in PR

4 IG‐001 recommends

inappropriate methods for

estimating TLD uncertainty.

Closed on August 25, 2006 / Octo

Revision 2 of IG‐001 eliminated re

inappropriate methods for TLD un

includes guidance that directs the reconstructor to site specific docu

when available.
IG‐001, Rev 1 Review Findin

# Finding Resolution

5 IG‐001 recommends a range

of LOD values for 1956‐1960

that the reviewer considers

too low for the period.

Closed on August 25, 2006 / OctoIn Revision 2, Table 2.1 that refere

values for the 1956–1960 period hmodified to remove any date‐spec

values.

6 Guidance implies that LOD for

deep dose from gamma mayalso be applied to electrondose, which is inconsistent

with historical data that show

uncertainty for shallow dose isconsiderably higher than deepdose.

Closed on August 25, 2006 / Octo

Revision 2 of IG‐001 removes the 

implies LOD for deep dose from ga

appropriate for electron dose.
IG‐001, Rev 1 Review Findin

# Finding Resolution

7 IG‐001 assumes NTA film

dosimeters were insensitive to

neutron below 500 keV,

however, reviewer contends

that the dosimeter is

insensitive to neutron <1 MeV.

Closed on August 25, 2006 / OctoRevision 2 indicates that a variety thresholds for NTA film dosimeter

the literature and recommends respecific information for determinithreshold values.

8 Methods for reconstruction of

neutron doses from survey

data or source term data do

not appear practical,achievable, and defensible.

Closed on July 31, 2012

Revision 3 has included the use of 

practical methods such as employ

to‐photon ratios.
IG‐001, Rev 1 Review Findin

# Finding Resolution

9 IG‐001 does not acknowledge

the likely use of neutron/

photon ratio methods in

neutron dose reconstructionand erroneous states that “... at

most facilities, neutron

exposure were generally less

than 20% of the photonexposures.”

Closed on August 25, 2006 / OctoRevision 2 modified Section 2.2.2 the offending statement, and intr

statement acknowledging the use 

specific neutron‐to‐photon ratios

10 IG‐001, Appendix B, DCFs for

bone surface and red marroware underestimated.

Closed on August 25, 2006 / Octo

Revision 2 recommends applying factor to the rotational and isotro

bone surface and red marrow (as 

esophagus and lung).
IG‐001, Rev 1 Review Findin

# Finding Resolution

11 IG‐001 does not account for

additional laboratoryuncertainty for film badgereadings associated withexposure less than 200 mrem.

Closed on August 25, 2006 / OctoRevision 2 added guidance to Sectindicating that site‐specific dosim

be available in the site profile.

12 IG‐001, Appendix B, PA

geometry DCFs are in errorand underestimates dose (i.e.,assumes the dosimeter is

worn on the posterior).

Closed on February 5, 2013

Posterior to anterior (PA) DCFs are routinely used in DRs. However, s

could prove useful in some speciascenarios (if used correctly), the P

should be kept in Appendix B.
IG‐001, Rev 1 Review Findin

# Finding Resolution

13 IG‐001, Appendix B,

rotational and isotropicgeometry DCFs are in error

and underestimates dose.

Closed on August 25, 2006 / OctobeRevision 2 has introduced a discussioof correction factors to be applied to and isotropic DCFs for bone (surface

marrow), esophagus, and lung.

14 Angular sensitivity not

accounted for in ‘correcting’measured film or TLDvalues.

Closed on August 25, 2006 / Octobe

Revision 2 added a discussion on the 

response of dosimeters to Section 4, 

guidance that directs the dose reconsite specific documentation.
IG‐001, Rev 1 Review Findin

# Finding Resolution

15 No correction recommended

for backscatter; may be

significant factor for pre‐1984

when calibrations were done

‘in air’ as opposed to ‘on‐

phantom.’

Closed on July 27, 2006

Non‐correction for backscatter on

reported film dose higher, buildin

conservativeness in early years.

16 Environmental uncertainty

(i.e. heat, humidity, light, etc.)

was not addressed IG.

Closed on February 5, 2013

IG‐001 contains general guiding in

but does not provide specific instr

follow during dose reconstructioninstructions are provided in site‐sp

issue‐specific technical documentworkbooks.
IG‐001, Rev 1 Review Findin

# Finding Resolution

17 Guidance for the selection of

uncertainty distributions for

total organ dose raisesquestion of consistency andrequires professional

judgment.

Closed on February 5, 2013

IG‐001 contains general guiding in

but does not provide specific instr

follow during dose reconstructioninstructions are provided in site‐sp

issue‐specific technical documentworkbooks.
IG‐001, Rev 2 Review Findin

# Finding Resolution

18 SC&A’s review of IG‐001,

Revision 1, identified several

deficiencies regarding the

clarity and structure of the

document.

Closed on July 31, 2012

Revisions 2 & 3 eliminated much o

excessive data and generally impr

clarity of the document.

19 A deficiency (Finding 1)

identified under the Revision 1review was the fragmented

structure and illogical

sequencing of information.

Closed on November 1, 2012

What constitutes the logical, versu

sequencing of information is a fair

determination. Importantly, the s

information within the document 

factor in providing adequate guida
IG‐001, Rev 2 Review Findin

# Finding Resolution

20 Guidance was not provided

regarding the methodologyfor the assessment ofneutron doses using source

term data.

Closed on November 1, 2012

IG‐001 provides general principles, 

guidance. Detailed implementation 

and related information is found in documents and procedures.

21 IG‐001 does not consistently

direct the dose reconstructor

to technical and site‐specific

documents .

Closed on July 31, 2012

This finding is virtually identical to F
IG‐001, Rev 2 Review Findin

# Finding Resolution

22 OCAS‐IG‐001 should (but

does not) direct the dose

reconstructor to technicaland site‐specificdocumentation, were the DR

can find more specific

guidance.

Closed on November 1, 2012

IG‐001 provides general principles, 

guidance. Detailed implementation 

and related information is found in documents and procedures.

23 No discussion added to this

revision regarding neutron‐to‐photon ratios.

Closed on July 31, 2012

Revision 3 added a discussion to Se

2.2.2.2.1 to clarify the evaluation of neutron data, by recommending th

specific neutron‐to‐photon dose rat
IG‐001, Rev 2 Review Findin

# Finding Resolution

24 (1) All DCFs associated with PA

geometries in Appendix B arein error and underestimatedose.(2) Environmental uncertainty

associated with doimeters are

not addressed.(3) Guidance for selection of

uncertainty distributionsraises questions of consistencyand required professionaljudgment.

Closed on February 5, 2013

Posterior to anterior (PA) DCFs are routinely used in DRs. However, s

could prove useful in some specia

scenarios (if used correctly), the P

should be kept in Appendix B.

IG‐001 contains general guiding in

but does not provide specific instr

follow during dose reconstructioninstructions are provided in site‐sp

issue‐specific technical documentworkbooks.
Questions?