Cover title.

Executive summary -- Introduction: Setting the security and safety context -- Radioactive sources -- Ranking of radioactive sources and radioisotopes by security risk -- Radiological weapons--radiological dispersal devices -- Lifecycle of radioactive sources -- Overview of the radioactive source production and distribution industry -- Regulatory and industry efforts to secure radioactive sources -- Conclusions and recommendations -- append. 1. Probable health effects from exposure to ionizing radiation -- append. 2. Reactors known to produce radioisotopes.