Personnel dosimeter angular response properties and the adoption of ICRU Report 39 quantities

A new set of quantities for applied health physics has been proposed in the International Commission on Radiation Units and Measurements publication 39 (1985), with the recommendation that they be based on the ICRU sphere phantom model. The quantities proposed for individual monitoring, which incorporate specific non-isotropic angular response properties, are designed to provide an estimate of an individual's effective dose equivalent (HE). They are the individual dose equivalent superficial (Hs(d)) and penetrating (Hp(d)). Our study of typical dosimeter-wearing practices indicated that there were no consistent locations on or angular orientations of dosimeters to the wearer's body. This demonstrated the difficulties in the practical implementation of personnel dosimeters having an angular response approximating Hp(d) for a specifically selected point on a body, rather than the traditionally assumed design goal of dosimeters utilizing an isotropic response. It also indicated the importance that dosimeters utilizing a Hp(d) response have an adequate means of mounting the dosimeter on a body to assure the required dosimeter orientation to the body under a wide range of conditions of application. Questions also remain as to how the specified ICRU sphere reference phantom (or an approximation thereof) can be used as a practical testing laboratory phantom [corrected].