Convert centigray [cGy] to millirad [mrd] Online | Free radiation-absorbed-dose Converter

Centigray [cGy]: A Practical Unit in Radiation Therapy

The centigray (cGy) is a unit of absorbed radiation dose equal to 0.01 grays (Gy), or one-hundredth of a gray. It is widely used in clinical settings, especially in radiation therapy, where doses need to be both precise and clinically meaningful. One centigray equals 10 milligrays (mGy), making it a convenient unit for prescribing and documenting treatment doses.

In cancer treatment, therapeutic radiation is typically delivered in fractions, with each session often delivering 180–200 cGy (or 1.8–2.0 Gy) to the target area. Using centigrays allows healthcare professionals to express these fractions in whole numbers, simplifying treatment planning and communication. For example, a full course of radiation therapy might involve a total dose of 6000 cGy over several weeks.

Outside of therapy, the cGy is less commonly used, but it remains important in any context where mid-level radiation doses are applied or studied. Its use bridges the gap between small exposures (measured in mGy or µGy) and large, high-dose applications (measured in Gy), making the centigray a key unit in applied radiation science.

Millirad [mrd]: A Subunit of Radiation Absorbed Dose

The millirad (mrd) is a unit of absorbed radiation dose equal to one-thousandth of a rad. The rad (radiation absorbed dose) is an older, non-SI unit that was commonly used before the gray (Gy) became the standard.

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  1 rad = 0.01 gray (Gy)

  
  
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  Therefore, 1 millirad = 0.001 rad = 0.00001 Gy (10⁻⁵ Gy)

  
  

The millirad was used to measure the amount of energy absorbed from ionizing radiation per unit mass, primarily in radiation protection and medical contexts.

Though the rad and its subunits like the millirad have largely been replaced by the gray and its subunits (milligray, microgray, etc.), they may still be encountered in older literature or certain regions.

In summary, the millirad is a very small dose unit equal to one-thousandth of a rad, useful historically for quantifying low-level radiation exposures before the universal adoption of the gray.