The \"Q System\" and the Radiotoxicity of the Radionuclides

The first edition of the International Atomic Energy Agency (IAEA) \"Regulatjons for the safe transport of radioactive materials\" was issued in 1962 (IAEA Vienna 1962). The transported radionuclides were distributed jnto three groups according to their radiotoxicity. The radiotoxicity was evaluated by means of an \"injury index\" taking into account the dose equivalent received following a \"mean accident\" by incorporation, by inhalation, by ingestion or by wound. The 1962 regulations introduced the terminology of type A and type B packages and the nature of \"mean accident\" during which a person can incorporate an activity equal to 1/ 106 of the activity contained in the type A package. The reference dose equivalent was equal to 1/ 4 of the annual limit of equivalent dose for workers (in the following, we use \"dose\" in place of \"equivalent dose\").