Radiotherapy
The medical use of ionising radiation to destroy cancerous tissue.
Unit
Gy
In depth
Radiation damages DNA, and rapidly dividing cancer cells are less able to repair that damage than normal tissue. Treatment is fractionated over several weeks and beams are directed from multiple angles so that the tumour receives a high dose while surrounding tissue receives much less.
Examples in the real world
External beam therapy with a linear accelerator; brachytherapy implanting iodine-125 seeds directly in a tumour.