Skin deep [Terahertz radiation for medical applications]

Terahertz radiation has the potential to spot explosives, drugs and cancers. It could be useful for medical applications but, as the body contains a large percentage of water, it cannot diagnose many forms of cancer. But it seems to be good at picking out the extent of tumours under the surface of the skin that are invisible under visible light. It is concluded that terahertz radiation is slowly emerging as a technique that can open up new applications.