Aug 20 (Reuters) - People who survived the atomic bombings of Hiroshima and Nagasaki as children continue to have a higher-than-normal risk of thyroid cancer more than 50 years after radiation exposure, according to a U.S. study. Thyroid cells are particularly vulnerable to ionizing radiation, the kind produced by the Chernobyl nuclear meltdown or the atomic bombings in Japan. The study published in the International Journal of Cancer tracked new cancer diagnoses in people who were in Japan during the bombings in 1945 and those who were not. In total, there were 371 thyroid cancers diagnosed between 1958 and 2005...