Proceedings of the International School of Physics ''Enrico Fermi'' : Course LXVI / ed. by J. Baarli. Baarli, J. Medical physics Health Physics 610.158 INM New York : North-Helland, c1977. c1977. 1981 Text xvi, 535 p. : eng Proceedings ofthe International School of Physics ''Enrico Fermi'' Course LXVI.