Technetium (Tc-99m), the decay product of molybdenum-99 (Mo-99), is an essential component in cardiac nuclear imaging. In the past, the primary source for this radioisotope was highly enriched uranium (HEU), but market dynamics and legislative action have changed that. The last five years have seen a sustained move to low-enriched uranium (LEU), and the United States is expected to be fully transitioned to LEU by the end of 2018.
The Call for Change
The American Medical Isotope Protection Act of 2011 was enacted to not only promote the domestic production of molybdenum-99, but to replace the role of HEU in the production of medical radioactive isotopes.
Uranium is considered highly enriched when the concentration of the U-235 isotope exceeds 20%. If the proportion of U-235 is less than 20%, it’s categorized as low enriched uranium (LEU).
In an effort to reduce the amount and potential misuse of HEU, the Department of Energy promoted an initiative to reduce the dependence on HEU in the United States. Reactors around the world responded and have been moving toward the conversion from HEU to a process that uses LEU.
What the Move from HEU to LEU Means for Nuclear Imaging
The final product, Tc-99m, remains exactly the same regardless of the source material. There is no difference in the quality or effectiveness – only the raw material processed by the radiopharmacy. Both LEU and HEU approaches result in the same isotope with equivalent performance.
Even though there have been changes in the production process, nuclear medicine providers will not be affected by the shift. The availability of isotopes sourced from LEU generators is steadily increasing as the conversion continues throughout 2018.
U.S. manufacturers who produce Technetium-99 generators, and supply the radiopharmaceutical industry, are in full support of the conversion and are establishing a steady supply of radioisotopes derived from LEU sources. Although some feared that the shift would increase isotope prices, it appears that much of the conversion costs have already been factored in, and no dramatic increases are expected.
Ultimately the move from HEU to LEU will result in a more stable market and reliable supply of Tc-99 which is positive for the entire industry.