Radiation Safety Practice Exam

What is the international unit of measure for an Absorbed Dose?

1. Rad (rd)

2. Sievert (Sv)

3. Gray (Gy)

4. Rem (roentgen equivalent man)

The correct answer is: Gray (Gy)

The international unit of measure for an absorbed dose is the Gray (Gy). The Gray is defined as the absorption of one joule of ionizing radiation energy by one kilogram of matter, and it is a standardized unit in the International System of Units (SI). This unit quantifies the amount of energy deposited in a material, which is crucial for assessing the potential biological effects of radiation exposure. By using the Gray, professionals in radiation safety and medical fields can communicate and compare measurements consistently across different scenarios and studies. This consistency is vital for research, regulatory standards, and ensuring safety protocols are effective. In contrast, the Rad, while historically used, has been largely replaced by the Gray in most contexts involving absorbed dose due to its alignment with the SI units. The Sievert and Rem are units related to dose equivalents, which take into account the biological effects of radiation rather than just the absorbed dose, further distinguishing the proper context of the Gray as the absorbed dose measurement.