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Behrens, R.* ; Dietze, G.* ; Zankl, M.

Dose conversion coefficients for electron exposure of the human eye lens.

Phys. Med. Biol. 54, 4069-4087 (2009)
DOI PMC
Open Access Green as soon as Postprint is submitted to ZB.
Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. Two questions arise from this situation: first, which dose quantity is related to the risk of developing a cataract, and second, which personal dose equivalent quantity is appropriate for monitoring this dose quantity. While the dose equivalent quantity H-p(0.07) has often been seen as being sufficiently accurate for monitoring the dose to the lens of the eye, this would be questionable in the case when the dose limits were reduced and, thus, it may be necessary to generally use the dose equivalent quantity H-p(3) for this purpose. The basis for a decision, however, must be the knowledge of accurate conversion coefficients from fluence to equivalent dose to the lens. This is especially important for low-penetrating radiation, for example, electrons. Formerly published values of conversion coefficients are based on quite simple models of the eye. In this paper, quite a sophisticated model of the eye including the inner structure of the lens was used for the calculations and precise conversion coefficients for electrons with energies between 0.2 MeV and 12 MeV, and for angles of radiation incidence between 0 degrees and 45 degrees are presented. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are up to 1000 times smaller for electron energies below 1 MeV, nearly equal at 1 MeV and above 4 MeV, and by a factor of 1.5 larger at about 1.5 MeV electron energy.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords Vip-man; Radiation; Organ; Model
ISSN (print) / ISBN 0031-9155
e-ISSN 1361-6560
Journal Physics in Medicine and Biology
Quellenangaben Volume: 54, Issue: 13, Pages: 4069-4087 Article Number: , Supplement: ,
Publisher Institute of Physics Publishing (IOP)
Publishing Place Bristol
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Institute of Radiation Protection (ISS)