A deterministic effect describes Ionising Radiation induced damage where a Dose threshold exists, and for which the severity of damage increases with increasing Dose above that threshold. Examples will include radiation burns (skin reddening), hair loss, cataracts and radiation sickness (nausea, vomiting and diarrhoea). All of these effects results from acute high doses of radiation to either a part of the body or the whole body. For whole body exposure it is generally thought that an absorbed dose of between 3-5 Gy will cause 50% of those exposed to die within 30 days if medical intervention is not given. This is known as the LD-50 dose.