Dose limits for occupational skin exposure to ionising radiation

URN: urn:nbn:de:101:1-201309238372

In their more recent analysis of data on atomic bomb survivors in 2007 Preston and his co-authors also analysed the excess relative risk (ERR) for the incidence of non-melanocytic skin cancer. In view of this analysis, in a letter of 22 June 2009 the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety instructed the German Commission on Radiological Protection (SSK) to examine whether the present limitation of the skin organ dose together with the limitation of the effective dose can still be considered sufficient protection against stochastic impacts on the skin and which conclusions must or can be drawn with regard to protection against radiation exposure at the workplace.

In its expert statement adopted at the 251st meeting on 25 October 2011, the German Commission on Radiological Protection concludes that:

• The new analysis of the data of the Life Span Study cohort results in valid risk assessments with regard to a homogeneous skin exposure to ionising radiation.
• The new analyses by Preston et al. (2007) basically confirm the former results of the Life Span Study. Therefore it does not seem to be necessary to modify the limits for the skin organ dose together with the limitation of the effective dose.

Persons with an occupational exposure to radiation generally experience dose inhomogeneities and varying exposures for sites of different epidermis thickness. However, this is not the case with the cohort of the Life Span Study. Dose inhomogeneities should be taken into account if the results of the Life Span Study are to be applied to occupational exposure to radiation.

Applying the surface personal dose Hp(0.07) to describe the local skin dose at the hands is not an ideal approach. A new concept which, for example, would take into account the varying skin thickness at different sites and the related dose reduction depending on the radiation energy needs to be discussed on the international level.

As yet there is only very limited data on occupational skin exposure to ionising radiation in Germany. Such a data collection would be desirable as a basis for epidemiological analyses.