Shallow dose equivalent

Shallow-dose equivalent (Us), which applies to the external exposure of the skin or an extremity, is the dose equivalent at a tissue depth of 0.007 cm (7 mg/cm2) averaged over an area of 1 cm2. 

The limit on the annual occupational dose to the skin and other extremities is the shallow-dose equivalent of 50 rem (0.5 Sv). 

Shallow dose equivalent to the skin or to any extremity 50 rems (0.5 Sv) ... 

The assigned deep-dose equivalent and shallow-dose equivalent must be for the part of the body receiving the highest exposures. These data can be inferred from surveys or other measurements if direct data are not available. 

Shallow-dose equivalent for skin of 50 rems/year NRC ... 

There are two sources of dose that must be considered when calculating a person s dose external dose and internal dose. External dose is commonly measured with a dosimeter worn on the torso. Section 25.3.1 provides more information regarding calculating external dose. External dose is received for discrete intervals of time, such as when a person enters and exits a radiation area. When the person exits the radiation area, they are no longer receiving any external dose. Three different types of external dose are typically measured deep dose equivalent (DDE), shallow dose equivalent (SDE), and the dose equivalent to the lens of the eye (LDE). The SDE and the LDE are measured or calculated specifically to track the dose to the skin and the lens of the eye. For all other body parts, the DDE is used. 

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