Radiation is a double-edged sword for healthcare. The high-energy waves can be used to examine bones in X-rays and destroy tumours, but the same high-energy rays can be destructive, burning skin and damaging internal organs without any outward sign.
X-rays are a form of electromagnetic radiation, similar to but more intense than infrared, ultraviolet or microwaves. Radiation therapy uses X-rays and gamma rays delivered in a beam of high-energy light by an external source. Today, around 50 per cent of cancer patients benefit from radiation therapy in the treatment and management of their disease.
The rays actively divide cells in DNA and also oxidise water to make free radicals, which diffuse to the DNA. Splitting a double strand in the DNA in a tumour cell will kill it.
There are different modes of radiotherapy, from low-energy (kV) to high-energy (MV) X-rays for deeper penetration, to electron beam and cobalt therapy, using gamma rays. There is also...