Dose measured at 0.3 cm or 300 mg/cm2 is called?

• A. Lens Dose Equivalent
• B. Shallow Dose Equivalent
• C. Deep Dose Equivalent
• D. Whole Body Dose

Answer: (A)

The concept being tested is dose assessment at a specific tissue depth to protect a particular organ. The lens dose equivalent is defined as the dose to the eye lens at a tissue depth of 0.3 cm (3 mm). That depth corresponds to about 300 mg/cm2 of tissue mass, so measuring the dose there specifically reflects the risk to the eye lens from radiation. Hence, dose measured at 0.3 cm is called the Lens Dose Equivalent.

The other terms refer to different depths and parts of the body: shallow dose equivalent is for very shallow skin depths, deep dose equivalent is for deeper tissues, and whole body dose isn’t tied to a single tissue-depth measurement in the same way.