Which measurement unit is commonly used to express radiation exposure in diagnostic radiology?

The commonly used measurement unit to express radiation exposure in diagnostic radiology is the roentgen (R). The roentgen specifically measures the amount of ionization produced in air by X-rays or gamma rays. This makes it particularly relevant for assessing exposure levels in clinical settings where these types of radiation are used for imaging purposes. It provides a practical means of quantifying the dose of radiation patients may receive during diagnostic procedures.

In contrast to other units listed, the sievert (Sv) is more frequently used to express biological effects of radiation, taking into account the type of radiation and its impact on human tissue, rather than just the exposure. The gray (Gy) measures absorbed dose, reflecting the energy deposited in a material but does not convey exposure in the air. The rem, similar to sievert, is also a unit that accounts for biological effects and is less common in current practice due to the preference for the sievert in expressing equivalent dose. Thus, the roentgen remains the distinct choice for expressing radiation exposure in the context of diagnostic radiology.