Comparison of personal dose equivalent and effective dose

Some of the work of the Joint ICRP/ICRU Task Group in providing conversion coefficients for personal dose equivalent H-p(10) and in making comparisons with the protection quantity effective dose, E, for monoenergetic photons, neutrons and electrons is described. Because H-p(d) is defined in soft ti!;sue in the birdy and, at the time of writing the Task Group Report, there were few available calculations of dose equivalent in soft tissue in human phantoms, some approximations were required to examine the behaviour of the quantity. The calibration quantity in the ICRU tissue equivalent slab, H-p,H- slab(d), has also been examined. In general H-p(10) can provide a good measure of E without under-estimation or excessive overestimation, but there are exceptions to this in some circumstances, especially for neutron radiations. Such problems can be alleviated by suitable positioning of personal dosemeters, appropriate to the radiation field to which people are exposed, and ensuring the dosemeters are designed and calibrated to measure H-p(10).