Kilogray

Kilogray (symbol kGy) is a unit of absorbed dose of ionizing radiation. It equals 1000 gray (Gy), where one gray is the SI unit defined as one joule of energy absorbed per kilogram of matter. Thus, 1 kGy = 1000 J/kg.

It is used mainly in radiation processing industries and radiobiology to express large irradiation doses. The kilogray is a non-SI unit accepted for use with SI; common in contexts involving sterilization, food irradiation, and polymer processing, where doses range from a few kGy to several tens of kGy.

Typical ranges include sterilization of medical devices often requiring doses around 15-25 kGy; food irradiation commonly uses 1-10 kGy depending on product and regulatory requirements; polymer crosslinking can require tens to hundreds of kGy.

Biological impact: for living tissue, doses are measured in Gy; exposure to kilogray levels would cause extensive tissue damage and would be lethal. These levels are used for non-biological materials or for sterilization of products. In practice, dose rates and total dose are carefully controlled and monitored.

Conversions and relationships: 1 Gy = 0.001 kGy; 1 kGy = 1000 Gy = 10^3 J/kg. In older units, 1 Gy = 100 rad, so 1 kGy = 100 krad. Kilogray is widely used in radiation processing, even though the gray remains the primary SI unit for absorbed dose.