Personal dose equivalent
The operational dose quantity personal dose equivalent (Hp(d)) is defined as the equivalent dose in soft tissue at a suitable depth under a specified point on the body. The corresponding unit is sievert (Sv). It turns out that the personal dose equivalent Hp(10) is a good estimator of the effective dose.It remains unclear what the ICRP means by "a suitable depth" and "a specified point". Although the personal dose equivalent is explicitly defined for the human body, we will still have to use a phantom for measurements and calculations. In doing so, d indicates the depth in mm in the ICRU sphere.