The Future of Radiological Protection


Comments on the System of Radiological Protection

Author(s): Michael Moores 1, Sören Mattsson 2
( 1 IRS Ltd, Liverpool,UK; 2 Lund University, Malmo, Sweden)


Comments and discussion on the following areas are considered:

  • The system of radiological protection itself
  • Dose and risk assessments in CT
  • The development and implementation of effective dose concepts

One of the greatest problems faced by radiological protection results from its “social sensitivity”. Why are risks from ionising radiation still perceived differently by society, even though an enormous effort has been expended over many years to establish and promote a legal framework for radiation protection? Perhaps, radiation protection is perceived differently because of its desire to employ the so-called fundamental principles of justification and optimisation.

Average risks from non-natural causes may be compared quantitatively in terms of a micromort unit, where1 micromort represents a risk of 1 in 1 million of dying from an activity. This unit can be used to compare risks, whether arising from an exposure to ionising radiation or any other potentially dangerous activity. It will be shown that other common activities, for example travel by road, can carry greater risks, but society does not yet feel the need for journeys to be justified nor has it established the minimisation of accidents as an international goal. Indeed, justification of any activity is automatically conferred by society when it operates within the appropriate legal framework.

The scope for forefront IT applications to CT dosimetry as well as patient dosimetry in general, is enormous. Utilising imaging information in conjunction with anthropomorphic phantom based modelling employing Monte Carlo calculations, could provide accurate risk- based information as part of routine practice. Organ dosimetry associated with all types of examinations and age groups can provide a unique and relevant framework for population risk studies leading to improvements in the setting of target optimised doses. The use of Dose Reference Levels (DRLs), a collective public health initiative is of little or no value to optimisation when applied to individual patients. This is in contradistinction to the ongoing development of the concept of personalized medicine.

Whole body doses arising from broad beam irradiations may provide suitable risk estimates for occupationally exposed individuals. However, this is not the case for most medical exposures, which involve partial body irradiation. To undertake detailed comparative population risk studies arising from medical exposures, which is the largest source of man-made exposure, accurate means of assessing effective doses are required. However, ideally effective dose needs to take cognisance of the differing radiation sensitivities that might occur in any population. Thus, detailed knowledge of genetic or other predispositions to radiation induced mutations is also a necessary scientific component.

Keywords: Social sensitivity; Risk management; CT dosimetry; Effective dose