Which unit is used to express dose equivalent in radiology?

Which unit is used to express dose equivalent in radiology?

• A. Rad
• B. Rem or sievert
• C. Gray
• D. Roentgen

Answer: (B)

Dose equivalent expresses the potential biological effect of radiation and is reported in the SI unit sievert, with rem used in older literature. It combines the amount of energy absorbed with factors that reflect how different radiations and tissues differ in biological impact. Absorbed dose is measured in grays, which tells you energy per mass, but it doesn’t account for how damaging that radiation is to living tissue. Roentgen measures exposure in air and is not a measure of biological effect. Because dose equivalent accounts for quality of radiation and tissue sensitivity, sievert (or rem in legacy usage) is the appropriate unit.

Dose equivalent expresses the potential biological effect of radiation and is reported in the SI unit sievert, with rem used in older literature. It combines the amount of energy absorbed with factors that reflect how different radiations and tissues differ in biological impact. Absorbed dose is measured in grays, which tells you energy per mass, but it doesn’t account for how damaging that radiation is to living tissue. Roentgen measures exposure in air and is not a measure of biological effect. Because dose equivalent accounts for quality of radiation and tissue sensitivity, sievert (or rem in legacy usage) is the appropriate unit.