Thallium poisoning is poisoning due to thallium and its compounds which are often highly toxic. Thallium and its compounds are extremely toxic, with numerous recorded cases of fatal thallium poisoning. Another application of thallium doping is the sodium iodide crystals in gamma radiation detection devices. All proposals include gallium, indium, tin, thallium, lead, and bismuth. The "metametals" are zinc, cadmium, mercury, indium, thallium, tin and lead. Simple eutectic systems, however, occur with bismuth, gallium, lead, thallium and zinc. They can consist of binary or ternary mixtures of thallium, arsenic and sulfur. It is the most popular isotope used for thallium nuclear cardiac stress tests. Several elements were discovered by spectroscopic means, including helium, thallium, and caesium. Police found thallium in his pocket and antimony, thallium and aconitine in his home. Some say Thallium is a suspected human carcinogen. At anions have been reported to form astatides with silver, thallium, palladium and lead. It is made by the neutron activation of stable thallium in a nuclear reactor. There are numerous recorded cases of fatal thallium poisoning. Thallium and its compounds are often highly toxic.