Loyola University Medical Education Network

Thermal Neutron Reactor-Produced Radioisotopes

Radioisotopes used in Nuclear Medicine are almost all synthetic. For thermal neutron reactor-produced radioisotopes, reactor is source of thermal neutrons. An (n,gamma) reaction occurs. Net effect: increase of A number by 1 and no change in Z number. Same element is therefore present. Example: 98Mo (n,gamma) 99Mo

Reactor yield dependent upon:

The product of an (n,gamma) reaction or other reaction may be described in terms of specific activity, i.e., radioactivity per unit mass of the element present. Examples: µCi/mg, dpm/mM, Ci/uM, kci/mole. Various separation techniques are available to separate product from target. Requirement: chemical forms of element in target and product must be different to effect separation.


Stephen Karesh, PhD.

Last Updated: August 14, 1996
Created: March 1, 1996