Radiation Physics) at the University of Lausanne in Switzerland found traces of polonium, a rare, highly radioactive element, on Arafat's personal belongings, including his toothbrush, hat, surgical bouffant (headgear), and underwear, which suggested that there was a high level of polonium inside his body when he died. The investigation ruled out HIV or any other infectious disease as a cause of death. The polonium was found in quantities much higher than could occur naturally, and further, that 60%–80% of that polonium (depending on the item being tested) had not come from natural sources, but from a nuclear reactor. The quantities found on his personal items at the time of this investigation were generally consistent with quantities of polonium that would have been given to poison him when he suddenly first came down with major symptoms of illness. In October 2010, an official press release from the Institut de Radiophysique, where those items were analyzed, had stated that: In July 2012, a spokesman for the Institut de Radiophysique stressed that the "clinical symptoms described in Arafat's medical reports were not consistent with polonium-210 and that conclusions could not be drawn as to whether the Palestinian leader was poisoned or not", and that "the only way to confirm the findings would be to exhume Arafat's body to test it for polonium-210". François Bochud, who heads the Institute of Radiation Physics in Lausanne, Switzerland, stated that "our results are clearly not a proof of any poisoning". Alastair Hay, professor of environmental toxicology at the University of Leeds in England, stated: "You don't know much about the provenance of the clothing and whether it had been tampered with later on. You'd want to test the body." In response to Al Jazeera's report, Dr Ely Karmon, at Herzliya's Institute for Counterterrorism, a specialist in chemical, biological, radiological and nuclear terrorism, said that "the half-life of the substance [i.e., slightly more than 138 days 9 hours] would make it impossible for polonium to have been discovered at such high levels if it had been used to kill Arafat eight years ago. If it had been used for poisoning, minimal levels should be seen now. Yet much higher levels were found. Someone planted the polonium much later." He went on to question why Arafat's widow, Suha Arafat, who provided the researchers with Arafat's belongings was not also poisoned while she was by his side at the hospital