What is the SI unit for measuring absorbed dose equivalent?

• A. Gray
• B. Roentgen
• C. rem
• D. Sievert

Answer: (D)

The SI unit for measuring absorbed dose equivalent is the Sievert. The Sievert is used to quantify the biological effects of ionizing radiation on human tissue, specifically taking into account the type of radiation and its impact on the body. This unit is essential in radiology and radiation protection, as it allows for a more accurate assessment of the potential health risks from exposure to different types of radiation.

In the context of absorbed dose, which is measured in Grays, the Sievert provides a more comprehensive understanding by incorporating the biological effectiveness of the radiation. This distinction is crucial because not all radiation types produce the same level of biological damage, hence the need for a unit that reflects this difference. Other units like the Roentgen, which is used for measuring exposure to x-rays and gamma rays, and the rem, which is an older unit also used for dose equivalent, are not part of the current SI system.