The external dose is the dose equivalent received from radiation sources outside the body.

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.

The deep dose equivalent is related to the dose in tissue at a depth of one centimeter due to external radiation. Also called personnel dose equivalent at a depth of 1 cm. The unit for deep dose equivalent is J/kg or sievert (Sv).

The eye dose equivalent is the radiation dose of the lens of the eye taken by external exposure. The dose equivalent is calculated at a tissue depth of 0.3 centimeters (300 mg/cm2).