Can we put aside the LNT dilemma by the introduction of the controllable dose

Recently, Professor R Clarke, ICRP Chairman, published his proposal for a renewal of the basic radiation protection concept (1999 J. Radiol. Prot. 19 107-15). The two main points of his proposed system are: (a) the term `controllable dose' is introduced and (b) the protection philosophy is based on the individual. For practical use terms like `action level', `investigation level' etc are introduced. The outline of the new system promises a much less complex frame; no distinction between practices and interventions and unified treatment for occupational, medical and public exposures. There is, however, an inconsistency within the new system: though linearity is not assumed, the relations between the definitions of the new terms of the system of protection and the doses assigned to them are still based on the LNT hypothesis. To avoid this inconsistency a new definition of action level is recommended as a conservative estimate of the lowest dose where harmful effects have ever been demonstrated. Other levels should be defined by the action level and safety factors applied on the doses .