irradiation

noun

1. the condition of being exposed to radiation
2. a column of light (as from a beacon)
3. (physiology) the spread of sensory neural impulses in the cortex
4. the apparent enlargement of a bright object when viewed against a dark background
5. (Pavolvian conditioning) the elicitation of a conditioned response by stimulation similar but not identical to the original stimulus
6. (medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance