Directional dose equivalent

The operational dose quantity directional dose equivalent (H'(d,Ω)) is defined as the equivalent dose at point P at a depth of d mm in the ICRU-sphere (see Figure). The corresponding unit is sievert (Sv).

The radiation field in point P of the ICRU-sphere is extended, but - contrary to H^*(d) - not aligned. The equivalent dose will, therefore, depend on the direction from which the radiation comes. From the definitions, it follows that H^*(d) = H'(d,0°).

One distinguishes H'(10,Ω) for penetrating radiation, H'(3,Ω) for the lens of the eye, and H'(0.07,Ω) for the skin.

Related quantities

• absorbed dose
• ambient dose equivalent
• collective effective dose
• committed effective dose
• committed equivalent dose
• effective dose
• equivalent dose
• exposure
• irradiation geometry
• kerma
• personal dose equivalent
• radiation weighting factor
• tissue weighting factor