In the example, what unit is used to express the unfiltered beam intensity?

In the example, what unit is used to express the unfiltered beam intensity?

• A. Microgray (uGy)
• B. Gray (Gy)
• C. Milligray (mGy)
• D. Nanogray (nGy)

Answer: (A)

Energy deposited per unit mass is measured in Grays, but when the beam’s strength is very small—as with an unfiltered X-ray beam—the practical way to express it is in micrograys. One microgray equals one millionth of a Gray, so it keeps the number convenient without losing the meaning of the dose-like quantity being described. A milligray would imply a much larger dose than is typical for unfiltered beam intensity, while a nanogray would be far too small to represent practical measurements. Using microgray conveys that the unfiltered beam delivers a tiny amount of energy per kilogram, which is the right scale for this context.

Energy deposited per unit mass is measured in Grays, but when the beam’s strength is very small—as with an unfiltered X-ray beam—the practical way to express it is in micrograys. One microgray equals one millionth of a Gray, so it keeps the number convenient without losing the meaning of the dose-like quantity being described. A milligray would imply a much larger dose than is typical for unfiltered beam intensity, while a nanogray would be far too small to represent practical measurements. Using microgray conveys that the unfiltered beam delivers a tiny amount of energy per kilogram, which is the right scale for this context.