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Radiation Dose Units Converter

Gamma rays, X-rays, Beta particles, Electrons (electron beam therapy, radiotherapy, diagnostic radiology, CT scans, cross-country flights)

Gray (Gy)

Milligray (mGy)

Sievert (Sv)

Millisievert (mSv)

Rad

Rem

Cancer Risk (% per Sv)

Long flights (Hours)

Number of Chest X-rays

Alpha Particles, Heavy Ions (International Space Station, Moon, Mars, cosmic radiation, radon exposure)

Gray (Gy)

Milligray (mGy)

Sievert (Sv)

Millisievert (mSv)

Rad

Rem

Cancer Risk (% per Sv)

International Space Station (Hours)

Staying on Moon (Hours)

Staying on Mars (Hours)

Radiation Conversion Explanation

To convert Gray (Gy) to Sievert (Sv), use the radiation weighting factor (w_R):

Sievert = Gray × w_R

⚠️ Radiation Weighting Factors (w_R):

Radiation Type	w_R	1 Gy equals how many Sv?
Gamma rays / X-rays / Beta particles	1	1 Gy = 1 Sv (1000 mGy = 1000 mSv)
Alpha particles / Heavy ions	20	1 Gy = 20 Sv (1000 mGy = 20,000 mSv)

1 Sv = 1000 mSv = 100 rem ≈ 5% increased lifetime fatal cancer risk. Image Wisely, Frontiersin, NCBI