What is the derived unit used to measure ionizing radiation dose?

The derived unit used to measure ionizing radiation dose is the Gray (Gy). This unit quantifies the amount of radiation energy absorbed by a material, particularly biological tissue, with a focus on the effects of radiation on living organisms. Specifically, one Gray is defined as the absorption of one joule of radiation energy per kilogram of matter.

Using the Gray as a measurement helps to standardize the assessment of radiation exposure, allowing healthcare professionals and researchers to compare the biological effects of different types of radiation. It is widely used in medical applications, particularly in radiation therapy for cancer treatment, where determining the correct dosage is critical for maximizing treatment efficacy while minimizing harm to healthy tissues.

The other options—Rontgen, Rad, and Sievert—are related to radiation but serve different purposes or contexts. For example, Rontgen measures exposure in air rather than dose absorbed by tissue, while Rad is an older unit that is being largely replaced by the Gray. The Sievert, on the other hand, accounts for the biological effect of ionizing radiation and is used mainly for dose equivalent measurements rather than direct energy absorption like the Gray.