A dose is named chronic when the exposure is longer than one day.
Chronic radiation doses can be low enough to cause few effects, and they can be severe enough to be extremely dangerous.

In radiology dose is the term for radiation related to the amount of energy absorbed in matter (for example absorbed dose, acute dose, effective dose, external dose, personal dose and committed dose equivalent). The SI standard unit of radiation dose is the gray.
Dose refers also to the amount of medication, radiopharmaceutical or contrast medium used in diagnostic imaging.

See also Deep Dose Equivalent, Critical Organ, Eye Dose Equivalent, Collective Effective Dose, Medical Internal Radiation Dose Committee, and Chronic Dose.