What does Air Kerma measure?

Air Kerma is primarily a measure of the energy transferred from ionizing radiation to matter, specifically to air, and it is quantified in terms of Joules per kilogram. This means that Air Kerma is expressed in Gray (Gy), which is the SI unit representing the absorbed dose of ionizing radiation. One Gray is equivalent to one Joule of energy absorbed per kilogram of the material.

The significance of Air Kerma is that it provides an indication of the radiation exposure in a certain volume of air, which is crucial when evaluating the dose that might be received by patients or personnel during diagnostic imaging or therapeutic procedures. This measurement helps in assessing potential biological effects of radiation exposure.

In contrast, the other choices refer to different concepts. For instance, while the measurement of absorbed dose in mRem (millirem) does relate to radiation exposure, it is more aligned with equivalent dose rather than specifically measuring Air Kerma. Similarly, energy absorbed by tissue and equivalent dose in Sieverts are also related but represent other aspects of radiation exposure and its effects on biological tissues rather than the specific metrics associated with Air Kerma.