The directional dose equivalent is the equivalent dose at a point in a radiation field that would be produced by the corresponding expanded field at depth on a radius in a specified direction. The unit of directional dose equivalent in the SI system of units is joule per kilogram (J/kg) and sievert (Sv).

The dose limit is the highest value of an applied or allowed radiation exposure. The radiation dose is limited in order to prevent the occurrence of radiation-induced deterministic effects or to limit the probability of radiation-related stochastic effects to an acceptable level.

See also Whole Body Counter, Thermoluminescent Dosimeter, Dosimetrist, Annual Limit On Intake, Committed Effective Dose Equivalent, Computed Tomography Dose Index, Directional Dose Equivalent, Doubling Dose.