The formation of atom-doped fullerenes has been investigated by using several types of radionuclides produced by nuclear reactions. It was found that the endohedral fullerenes (Kr@C-60, Xe@C-60) and their dimers, furthermore, heterofullerenes, such as AsC59, GeC59 and their dimers, are produced by a recoil process following nuclear reactions. Other nuclear reaction products (Na, Ca, Sc, etc.) may destroy most of the fullerene cage in the same process. Carrying out ab initio molecular-dynamics simulations based on an all-electron mixed-basis approach, we confirmed that the formation of Kr- (or Xe-) atom-doped endohedral fullerenes and of substitutional heterofullerenes doped with an As atom is really possible. The experimental and theoretical results indicate that the chemical nature of doping atoms is important in the formation of foreign-atom-doped fullerenes.