Radiation Safety Practice Exam

Which of the following units is specifically known for measuring absorbed dose?

1. REM

2. Gray

3. Becquerel

4. Sievert

The correct answer is: Gray

The unit known specifically for measuring absorbed dose is the Gray. The Gray is defined as the absorption of one joule of radiation energy by one kilogram of matter. This unit quantifies the amount of energy deposited by ionizing radiation in a specific mass of tissue, making it essential in radiation safety, medical treatments, and radiation physics. Understanding the absorbed dose is crucial for evaluating the potential biological effects of radiation exposure, as it directly correlates to the energy imparted to the body. In contrast, the other units listed have different applications: REM (Roentgen Equivalent Man) measures the biological effect of radiation, taking into account the type of radiation and its potential to cause harm. Becquerel is the unit of radioactivity, representing the decay of radioactive material (one disintegration per second), and is not concerned with the energy absorbed. Sievert also accounts for biological effects but measures dose equivalent, integrating absorbed dose with a quality factor to address the type of radiation. Therefore, while all these units relate to radiation exposure, only the Gray specifically directly measures absorbed dose.