Cyclotron production of NCA 99mTc and 99Mo. An alternative non-reactor supply source of instant 99mTc and 99Mo----99mTc generators.

The direct production of no-carrier-added (NCA) 6.02 h 99mTc and of 66 h 99mMo using proton beams of natural Mo targets was investigated. The major objective of this work was to evaluate the potential of utilizing high-intensity proton accelerators as a supply source of 99mTc and 99Mo for use in diagnostic nuclear medicine. The excitation functions for the production of the directly-made 99mTc via the 100Mo(p, 2n)99mTc (Q = -7.85 MeV) reaction, and of its parent 99Mo via the 100Mo(p, pn) 99Mo (Q = -8.30 MeV) and 100Mo(p, 2p)99mNb(15 s)----99Mo (Q = -11.14 MeV) reactions, were measured in the 68-8 MeV energy range. Single and cumulative yields for 99mTc and 99Mo, and for other Tc, Mo, Zr, Nb and Y radiocontaminants were also determined. The prospects of integrating the use of enriched 100Mo targets with high-intensity, dual beam, H- accelerators was analyzed. The potential of this combined method to replace or complement the current reactor-based supply sources of 99Mo----99mTc generators, is also discussed. Finally, a brief analysis is made on the potential use of this combined technology to support the anticipated expansion of nuclear medicine in developing nations.

Cyclotron production of no-carrier-added 206Bi (6.24 d) and 205Bi (15.31 d) as tracers for biological studies and for the development of alpha-emitting radiotherapeutic agents.

The production and radiochemical purification of no-carrier-added (NCA) bismuth isotopes (i.e. 6.24 d 206Bi and 15.31 d 205Bi) was studied. The Bi isotopes are intended for use as tracers in biodistribution studies and in the design and testing of alpha-emitting radiotherapeutic agents. The total cross sections and yields for the production of 206Bi and 205Bi from the proton bombardment of natural Pb targets were measured using the stacked-foils technique. A radiochemical method for the separation and purification of NCA Bi radioactivities from a multi-gram Pb target was also tested, modified, and improved to provide aqueous solutions of chemically and biologically useful amounts of NCA 206,205Bi for measuring tissue and subcellular-distributions, and for studies covering several chemical aspects of the development of Pb/Bi radiotherapeutic agents.