ASPECTS OF ICRP-60 AND ICRU-47 RELEVANT TO INDIVIDUAL MONITORING OF EXTERNAL EXPOSURE

Individual monitoring for external ionising radiations is required for persons who are occupationally exposed to radiation. The primary func tion of individual monitoring is providing information for the control of exposures and estimating the dose received by the individual. Indi vidual monitoring as practised is based on a radiation protection conc ept which includes a hierarchy of dose quantities. Exposure limits rec ommended by the ICRP and used in regulations are expressed in risk rel ated quantities such as effective dose or effective dose equivalent. O perational quantities such as ambient dose equivalent or personal dose equivalent are defined in phantoms and are designed to give reasonabl e estimates of exposure limiting quantities. The readings of individua l dosemeters are calibrated in terms of operational quantities. The in ternational commissions involved in the definition of risk related qua ntities (ICRP) and operational quantities (ICRU) have introduced vario us new definitions and modifications to previous quantities used in th eir respective publications ICRP 60 and ICRU 39, ICRU 47. The conseque nces of these alterations for the relationships between quantities wit hin the hierarchy have to be examined and the new quantitative relatio nships (conversion coefficients) between basic physical radiation quan tities such as particle fluence or air kerma and the new quantities ha ve to be evaluated. In 1992, the ICRP and ICRU charged a joint task gr oup with addressing these tasks with a view to revising ICRP Publicati on 51. This paper presents an outline for the subject of the report to be prepared by the task group. An introduction to the new phantom-bas ed quantities is given and conceptional differences between the newly introduced and the previous quantities are discussed.