Use of radioactive material has to be approved by a competent authority in the country concerned. One of the main principles governing the utilization of radioactive material is that it shall not pose danger to persons, neither those working with the materials nor the general public. In addition, the radiation doses

to which workers and the public are exposed should be within the limits set by laws and regulations.

Another principle is that use of radioactive material will be accepted only when the benefit is considerable, after having taken economic as well as health and environmental aspects into consideration.

A third principle is that when using radioactive material every effort should be made to keep the quantity of radioactivity to be used and the resulting radiation doses ALARA.