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How many rads are equal to one gray?

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linear accelerator; external beam radiation therapy — radiation therapy External beam radiation therapy (also known as external beam teletherapy, or long-distance therapy) being delivered using a machine known as a linear accelerator.

One gray (Gy) is equal to 100 rads.21

The gray is the standard unit of absorbed dose of ionizing radiation within the International System of Units (SI), representing the absorption of one joule of energy per kilogram of matter. It replaced the rad—an older unit defined as 100 ergs per gram—in 1975 to provide a more coherent system of measurement. While the rad is still occasionally used in the United States, the gray is the internationally recognized unit for quantifying radiation dose in medical and scientific contexts.21