$CT$ (computed tomography) and $MRI$ (magnetic resonance imaging) are very useful to detect cancers of the internal organs.

Computed tomography uses $X$-rays to generate a three-dimensional image of the internals of an object.

It is a radiological invasive technique.

It is used to detect diseases of brain, spinal-chord, chest and abdomen.

$MRI$ uses strong magnetic fields and non-ionising radiations.

It accurately detect pathological and physiolog-ical changes in the soft tissues like tumours, muscular disorders, haemorrhage etc.