Planar radiography doses are typically in the millirad range. Which option represents millirads?

Planar radiography doses are typically in the millirad range. Which option represents millirads?

• A. Grays
• B. Millirads
• C. Sieverts
• D. Rads

Answer: (B)

Planar radiography doses are described in very small absorbed-dose units. A millirad is 1/1000 of a rad, so the term that represents that scale is Millirads. This reflects the idea that the dose is on the order of thousandths of a rad. In contrast, grays are the SI unit of absorbed dose (1 Gy = 100 rad), rads are the older unit for absorbed dose but at the larger rad scale, and sieverts measure dose equivalent, not absorbed dose. So the label that corresponds to the millirad scale is Millirads.

Planar radiography doses are described in very small absorbed-dose units. A millirad is 1/1000 of a rad, so the term that represents that scale is Millirads. This reflects the idea that the dose is on the order of thousandths of a rad. In contrast, grays are the SI unit of absorbed dose (1 Gy = 100 rad), rads are the older unit for absorbed dose but at the larger rad scale, and sieverts measure dose equivalent, not absorbed dose. So the label that corresponds to the millirad scale is Millirads.