Certified Healthcare Safety Professional (CHSP) Practice Exam

What unit measures the amount of energy per unit mass absorbed by an irradiated object?

1. Roentgen Equivalent Man (REM)

2. Radiation absorbed dose (rad)

3. Radiation Safety Officer (RSO)

4. ALARA concept

The correct answer is: Radiation absorbed dose (rad)

The unit that measures the amount of energy per unit mass absorbed by an irradiated object is the radiation absorbed dose, commonly abbreviated as "rad." This measurement specifically quantifies the energy deposited by ionizing radiation in a material, often biological tissue, and is essential in assessing potential biological effects of radiation exposure. The rad is defined as the absorption of 100 ergs of radiation energy per gram of any material, indicating a direct relationship between radiation exposure and the biological risk involved. This makes it a crucial parameter in fields like radiation safety and health physics, as it helps in determining the necessary protective measures when working with or around sources of radiation. Other options listed focus on different aspects of radiation and safety. For instance, REM is a unit of dose equivalent that considers the biological effect of the type of radiation, while the Radiation Safety Officer is a role responsible for ensuring compliance with safety regulations. The ALARA concept refers to the principle "As Low As Reasonably Achievable," emphasizing minimizing radiation exposure rather than providing a measurement of radiation absorbed. Each of these options serves a different purpose and is important in the context of radiation safety, but they do not specifically measure the energy per unit mass like the rad does.