[ RadSafe ] Activity versus dose/exposure

[Hansen, Richard (CONTR)]

John,

Depending on your application, you may also want to look at 
IAEA-TECDOC-1162
Generic procedures for assessment and response during a radiological emergency
http://www-pub.iaea.org/MTCD/publications/PubDetails.asp?pubId=5926

This document has tables and formulas for calculating not just the external exposure from a point source, but also from internal exposure from various pathways. This document addresses some of the concerns that Franz mentioned. Are these procedures perfect? No, but I have found this document very useful. To use these procedures, you still need an estimates of radionuclides with activities and/or concentrations.

For Dose Assessment, see Procedures E0 through E8
Quotes from TECDOC-1162

In the event of an accident exposure of an individual may be external or internal and may be
incurred by various pathways. External exposure may be due to direct irradiation from the
source, airborne radionuclides in the air (immersion or exposure to an overhead plume),
radionuclides deposited onto the ground and onto person's clothing and skin. Internal
exposure follows from the inhalation of radioactive material either directly from a plume or
re-suspended from contaminated surfaces, from the ingestion of contaminated food and water
or through contaminated wounds

This section provides various methodologies for calculating doses and dose rates based on the
type of sources or radioactive materials involved and the circumstances of the emergency
situation. While the radiological assessor may have access to computer programs to make the
assessments, the procedures also provide written formulas so that calculations may be made
by hand if necessary.

Characterise the type of exposure involved and use the appropriate procedure(s)(E1-E7):

Point source E1
Line source and spill (small area) E2

Ground contamination (including inhalation from re-suspension) E3
Note: Ground contamination effective dose calculation includes external dose and committed dose from inhalation (resuspension)resulting from remaining on contaminated ground for the period of concern - 1st month, 2nd
month or lifetime (50 years).

Skin contamination E4 
(skin beta dose from material deposited onto skin or clothing)

Inhalation E5
(committed effective dose and equivalent dose to the thyroid from inhalation)

Ingestion E6
(based on Radionuclide concentrations in food, water or milk and radionuclide concentrations in soil and
Time of intake)

Air immersion E7
(effective dose from external exposure to gamma-emitting radionuclides in a radioactive plume)


Best regards,
Rick Hansen
Senior Scientist
CTOS - Center for Radiological/Nuclear Training at the Nevada National Security Site
National Security Technologies, LLC
Contractor to the United States Department of Energy
hansenrg at nv.doe.gov
www.ctosnnsa.org

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Date: Wed, 22 Jun 2011 12:42:19 -0400 (EDT)
From: "John Gerald Center, Jr" <john.center at wmich.edu>
Subject: Re: [ RadSafe ] Activity versus dose/exposure
To: "The International Radiation Protection (Health Physics) Mailing
	List"	<radsafe at agni.phys.iit.edu>

Thank you all,

This is one of the many reasons I signed up for RadSafe.  Quick help when my brain shuts down and interesting debate on topics of radiation safety.

Still glad to be a part of this list,

John

----- Original Message -----
> From: "Carol Marcus" <csmarcus at ucla.edu>
> To: "The International Radiation Protection (Health Physics) Mailing List" <radsafe at agni.phys.iit.edu>, "The
> International Radiation Protection (Health Physics) Mailing List" <radsafe at agni.phys.iit.edu>
> Sent: Wednesday, June 22, 2011 12:22:54 PM
> Subject: Re: [ RadSafe ] Activity versus dose/exposure
> Dear John:
> 
> It's called the "Specific Gamma-ray Dose Constant" and you can find a
> table of them on pp 6-10 to 6-14 in the third edition (1998) of
> Schleien, Slaback, and Birky's "Handbook of Health Physics and
> Radiological Health".
> 
> Carol S. Marcus, Ph.D., M.D.
> Depts. of Radiation Oncology and of Radiological Sciences
> David Geffen School of Medicine at UCLA
> 
-- 

------------------------------
Date: Wed, 22 Jun 2011 18:49:26 +0200
From: <franz.schoenhofer at chello.at>
Subject: Re: [ RadSafe ] Activity versus dose/exposure
To: "The International Radiation Protection (Health Physics) Mailing
	List"	<radsafe at agni.phys.iit.edu>, 	"The International Radiation
	Protection (Health Physics) MailingList"	<radsafe at health.phys.iit.edu>

Carol et al.,

It seems that there is a fundamental misunderstanding among many (most???) RADSAFErs. The dose after a nuclear contamination is only to a small percentage due to direct gamma-ray exposure, more important from inhalation,  but overwhelmingly due to ingestion.

Gamma-ray Dose Constants will not help to determine the dose after a nuclear accident. Additionally the contribution from alpha- and beta emitters may play an important role, depending on the circumstances of the accident. 

This is one of the lessons I learnt after the Chernobyl accident. 

Do you have data on food contamination around Fukushima and the diet of people living there? I doubt.

Franz