Production of medical isotopes by photon and neutron induced fission of natural U and Th

In recent decades, the demand for radioactive isotopes for medical diagnostics and radiation therapy is on the rise. The conventional tools for production of these isotopes are cyclotron based or nuclear fission using enriched uranium isotopes. While the ⁹⁹Mo is widely known as the fission product used in SPECT imaging, there are several other isotopes of half-lifes of a few days and of interest for medical uses. A recent review article showed a very interesting result that the fission fragment mass distributions are nearly independent of the fissioning nucleus and neutron energies. It, thus, suggests that one can employ unenriched natural elements of uranium and thorium at a research reactor to a great advantage. We performed an experiment with natural uranium at the SLowPOKE reactor of Saskatchewan Research Council, Saskatoon, Canada. We easily produced ⁹⁹Mo, ¹³²Te, ¹³³I and ¹³⁵Xe isotopes in a short irradiation experiment and made the quantitative estimates of production rates. We are in the process of carrying out this experiment with a thorium sample. Our presentation will give the results and draw conclusions. In addition, we can expect similar fragment distributions from photon induced reactions. By exciting giant dipole resonance in the fissioning nucleus, one expects copious production of isotopes. We are in the early stages of planning such measurements. India is well set for production with their reactors. Also, it is possible to produce MeV photons at the Indus Synchrotons of RRCAT by developing Laser Compton Scatter beamline. (author)