Hygienic requirements for measuring occupational exposure to external ionizing radiation sources

The basic principles are outlined of personnel protection from ionizing radiation. Significant for such protection are mainly dose limits in organs and tissues or the directly measured variables of derived working limits. The principle has been accepted that personnel exposure determination is not required for personnel for whom the exceedance of 3/10 of the annual highest permissible dose equivalents is highly improbable. This resulted in the concept of the ''controlled zone'' as the organizational and administrative implementation of the principle of ''controlled personnel'' and to the concept of the ''investigation level'' conditioned on the attainment of 3/10 of the annual highest permissible dose and indicating the purposefulness of further investigating possible consequences. In practice, personnel monitoring is classified as (1) routine monitoring aimed at continuous operations and ascertaining whether or not the projected protection precautions are enforced and working conditions satisfactory; (2) operational monitoring aimed at determining the course of a certain activity and limiting personnel exposure during the activity; (3) special monitoring introduced in emergency situations or suspected emergencies. Conclusions drawn from the protection concept for personnel external irradiation dosimetry are discussed. (B.S.)