Brain cancer. Coloured axial (horizontal) magnetic resonance imaging (MRI) scan through the head of a patient with secondary brain cancers (orange). The front of the head is at top in this view from below. The cancers have spread (metastasized) from a primary breast cancer. The spread of cancer to the brain is common. A systemic (whole body) treatment, such as anti-cancer drugs, is needed, but cancers are often inoperable and fatal at this stage. MRI scanning uses powerful magnetic fields and pulses of radio waves to produce slice images of the body.