Examples of apparatus and methods for transmutation of an element are disclosed. An apparatus can include a neutron emitter configured to emit neutrons with a neutron output, a neutron moderator configured to reduce the average energy of the neutron output to produce a moderated neutron output, a target configured to absorb neutrons when exposed to the moderated neutron output, the absorption of the neutrons by the target producing a transmuted element, and an extractor configured to extract the desired element. A method can include producing a neutron output, reducing the average energy of the neutron output with a neutron moderator to produce a moderated neutron output, absorbing neutrons from the moderated neutron output with the target to generate a transmuted element, and eluting a solution through the target to extract a desired element. In some examples, the target includes molybdenum-98, and the desired element includes technetium-99m.