Isotope R&D Priorities

Research and Development into Isotope Production is funded by the Isotope Development and Production for Research and Applications (IDPRA) subprogram of the Office of Nuclear Physics in the U.S. Department of Energy Office of Science.

A short list of IDPRA priorities includes:

* invest in new production approaches of alpha-emitting radionuclides, such as Ac-225, At-211
* invest in coordination of production capabilities and suporting research
* produce isotopes of the heavy elements, e.g. Cf, Ra, trans-uranium isotopes
* focused study and R&D on new or increased production of He-3
* re-establish domestic production and supply of stable isotopes
* robust investment into education and training

Priorities for Isotope research have been assessed by a number of expert panels, most recently by the Isotopes Subcommittee of the Nuclear Science Advisory Committee [NSAC-I Subcommittee] in their Isotopes for the Nation's Future: A long range plan [August 2009] and Compelling Research Opportunities Using Isotopes [April 2009].

The recommendations of these reports are summarized here.

"Compelling research opportunities were identified and presented in prioritized lists within the two areas of 1) biology, medicine, and pharmaceuticals, and 2) physical sciences and engineering. The third area 3) security applications did not have immediate research priorities but made a number of observations and recommendations that apply more broadly for the entire IDPRA program. While it is challenging to assess relative scientific merit across disciplines, we have identified the highest priorities for the most compelling research opportunities. These recommendations also define the relative priorities of opportunities in Tables 8 and 9.

There are compelling research opportunities using alpha-emitters in medicine. There is tremendous potential in developing far more effective treatments of cancers by the use of alpha- emitters in comparison to other radioisotopes. Therefore, development and testing of therapies using alpha emitters are our highest priority for research isotope production for the medical field. This priority is reinforced by the potential need for rapid action due to the 2012 deadline for downblending of current DOE stocks of U-233, a procedure that would eliminate its value as a source of Ac-225.

1. Invest in new production approaches of alpha-emitters with highest priority for Ac-225. Extraction of the thorium parent from U-233 is an interim solution that needs to be seriously considered for the short term until other production capacity can become available.

There is strong evidence for the potential efficacy of pairs of isotopes with simultaneous diagnostic/therapeutic capabilities. Table 8 of this report presents a prioritized list of isotopes that have the greatest research potential in Biology, Medicine, and Pharmaceuticals. NSACI finds the research opportunities offered with these pairs of isotopes to be the second highest priority in identifying compelling research opportunities with isotopes. Many of these isotopes could be produced at existing accelerator facilities. We recommend the maximization of the production and availability of these isotopes domestically in the U.S. through investments in research and coordination between existing accelerators. The panel felt that such a network could benefit all areas of basic research and applications from security to industry. This should include R&D to standardize efficient production target technology and chemistry procedures.

2. We recommend investment in coordination of production capabilities and supporting research to facilitate networking among existing accelerators.

The basic physical sciences and engineering group prioritized research opportunities across various disciplines and a summary of this prioritization is given in Table 9. The availability of californium, radium, and other transuranic isotopes, the first three opportunities in Table 9, are particularly important for research.

3. We recommend the creation of a plan and investment in production to meet these research needs for heavy elements.

Experts in the nuclear security and applications areas strongly consider the vulnerability of supply from foreign sources to be of highest priority. This concern was echoed strongly by all members of the subcommittee in from medicine to basic science and engineering. Additionally, the projected demand for ³He by national security agencies far outstrips the supply. This would likely endanger supply for many other areas of basic research. While it is beyond our charge, it would be prudent for DOE/NNSA and DHS to seriously consider alternative materials or technologies for their neutron detectors to prepare if substantial increases in ³He production capacity cannot be realized.

4. We recommend a focused study and R&D to address new or increased production of 3He.

The remaining isotopes in Tables 8 and 9 all are promising research opportunities, and funds for production from the Research Isotope Development and Production Subprogram would be well spent on targeted production of these isotopes to meet immediate research needs, especially if unique production opportunities arise. However, at this point in prioritization, NSACI concludes that larger, long-term issues should take priority. The darker tone of blue used in Table 9 is an indication of that.

An important issue for the use of isotopes is the availability of high-purity, mass-separated isotopes. The stable isotopes ⁷⁶Ge and ²⁸Si (³He is stable but obtained from the beta-decay of ³H, not by isotope separation) listed in Table 9 are needed in large quantities that present special problems. While no other individual stable isotope reached the level of the highest research priority, the broad needs for a wide range of mass-separated isotopes and the prospect of no domestic supply raised this issue in priority for the subcommittee. NSACI feels that the unavailability of a domestic supply poses a danger to the health of the national research program and to national security. NSACI recommends:

5. Research and Development efforts should be conducted to prepare for the reestablishment of a domestic source of mass-separated stable and radioactive research isotopes.

Vital to the success of all scientific endeavors is the availability of trained workforce. While the scientific opportunities have expanded far beyond the disciplines of radiochemistry and nuclear chemistry, the availability of trained personnel remains critical to the success of research in all frontiers of basic science, homeland security, medicine, and industry. The individual research areas must make concerted efforts to invest in work-force development to meet these needs. The isotope program has a special responsibility to ensure a trained workforce in the production, purification and distribution of isotopes.

6. We recommend that a robust investment be made into the education and training of personnel with expertise to develop new methods in the production, purification and distribution of stable and radioactive isotopes.

All of the issues and recommendations considered here will be important input for answering the 2nd NSACI charge (See Appendix 1) due in July 31, 2009, developing a long range plan for the IDPRA Program."