Which of these units is used to measure radiation dose?

The unit used to measure radiation dose is the Gray (Gy). This unit quantifies the amount of ionizing radiation absorbed by a material or biological tissue. Specifically, one Gray is defined as the absorption of one joule of radiation energy by one kilogram of matter. This measurement is crucial in fields such as radiology, radiation therapy, and radiological protection, as it directly relates to the potential biological effects of radiation exposure on tissues.

Decibels, on the other hand, are used to express the intensity of sound or the ratio of power levels, not radiation dose. Millimeters measure length and are not applicable for indicating radiation quantities. Joules measure energy in a general sense, rather than specifically addressing the absorption of radiation in a given mass. Thus, the Gray is the appropriate unit for assessing radiation dose, making it the correct choice in this context.