In Israel, a permit issued by the Ministry of Environmental Protection is required in order to install a source of radiation.  The permit refers to the source of radiation or a specific type of sources of radiation, and is subject to certain conditions.  Amongst these: measurement of maximal levels of exposure expected from the source of radiation based on technical data, operating the source of radiation for a defined period, and performing trial assessments over a period set by the law.

A segment of the electromagnetic spectrum in the range of wavelengths 1mm-1 micron, with a range of frequencies  from 300 GHz (Gigahertz) to 300 THz (Terahertz).

The number of new cases of a disease in a population during a defined period (usually one year).

A medical phenomenon or a disease that develops spontaneously or is due to an unknown source.

Unit of measurement of frequency, named after the physicist Heinrich Rudolph Hertz.  It expresses the number of cycles of electromagnetic waves per given time unit, usually one second.  It is designated by the name Hz.

A state of complete physical, mental and social wellbeing and not merely the absence of disease or infirmity.” (Source: WHO).

A type of brain tumor developing in the glia.These cells are the most common in the brain and serve as support for the neurons.

Continuous bands or groups of selected isolated frequencies in the electromagnetic spectrum.

The number of waves per time unit, usually one second.  The unit of measurement is the Hertz (Hz).

An atom or molecule containing unpaired electrons.Free radicals are active and unstable.