A comparison of the ellipsoidal and voxelized dosimetric methodologies for internal, heterogeneous radionuclide sources

Ruedig, Elizabeth; Beresford, Nicholas A.; Gomez Fenandez, Mario Enrique; Higley, Kathryn. 2015 A comparison of the ellipsoidal and voxelized dosimetric methodologies for internal, heterogeneous radionuclide sources. Journal of Environmental Radioactivity, 140. 70-77. 10.1016/j.jenvrad.2014.11.004

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Official URL: http://dx.doi.org/10.1016/j.jenvrad.2014.11.004

Abstract/Summary

Non-human biota dosimetry has historically relied on ellipsoidal dosimetric phantoms. In 2008, the International Commission on Radiological Protection (ICRP) presented a set of ellipsoidal models representative of wildlife, including dosimetric data for homogeneously distributed internal radionuclide sources. Such data makes it possible to quickly and easily estimate radiation dose rate. Voxelized modeling, first developed for use in human medical dosimetry, utilizes advanced imaging technologies to generate realistic and detailed dosimetric phantoms. Individual organs or tissues may be segmented and dosimetric data derived for each anatomic area of interest via Monte Carlo modeling. Recently, dosimetric data derived from voxelized models has become available for organisms similar to the ICRP's Reference Animals and Plants in 2008. However, if the existing ellipsoidal models are conservative, there may be little need to employ voxel models in regulatory assessments. At the same time, existing dosimetric techniques may be inadequate to resolve recent controversies surrounding the impact of ionizing radiation exposure on wildlife. This study quantifies the difference between voxel-calculated and ellipsoid-calculated dose rates for seven radionuclides assumed to be heterogeneously distributed: 14C, 36Cl, 60Co, 90Sr, 131I, 134Cs, 137Cs, and 210Po. Generally, the two methodologies agree within a factor of two to three. Finally, this paper compares the assumptions of each dosimetric system, the conditions under which each model best applies, and the implications that our results have for the ongoing dialog surrounding wildlife dosimetry.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.jenvrad.2014.11.004
UKCEH and CEH Sections/Science Areas:	Shore
ISSN:	0265-931X
Additional Keywords:	radioecology, voxel phantom, dosimetry, non-human biota, Monte Carlo
NORA Subject Terms:	Ecology and Environment
Date made live:	06 Jan 2015 12:06 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/509226

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.jenvrad.2014.11.004

UKCEH and CEH Sections/Science Areas:

Shore

ISSN:

0265-931X

Additional Keywords:

radioecology, voxel phantom, dosimetry, non-human biota, Monte Carlo

NORA Subject Terms:

Ecology and Environment