(CNN) -  Yulia Gorelik describes her 8-year-old son Daniel as "a
very clever boy." He plays "Fur Elise" with elegant ease on the
piano and enjoys eating McDonald's chicken nuggets.  Mother and
son arrived in the United States earlier this summer through an
organization called Hope for Chernobyl's Child. Gorelik had
faith that American doctors could fix Daniel's headaches,
weakness and vertigo during their six-week stay.  "I have the
hope that we can do something here to make him stronger, because
he is intelligent, he is nice, but his body is weak," Gorelik,
34, told CNN in July.  The Goreliks live in a region called
Gomel, Belarus, which was heavily hit with radioactive fallout
from the worst nuclear accident the world has ever seen.  On
April 26, 1986, explosions at a reactor at Chernobyl in Ukraine
produced radiation effects almost 14 times greater than the 2011
Fukushima Daiichi disaster in Japan, and 400 times more powerful
than the 1945 atomic bomb dropped on Hiroshima.  More than 2
million people in Be