According to the NRC, which radionuclidic impurity must be determined for each Tc99m eluate?

The determination of radionuclidic impurities in Technetium-99m (Tc-99m) eluates is crucial to ensure safety and efficacy in radiopharmacy. Among the options presented, molybdenum-99 (Mo-99) is the parent radionuclide of Tc-99m and is of particular concern. When Tc-99m is produced from a Mo-99 source, some of the parent radionuclide may not fully decay, leading to contamination in the final product.

Regulatory guidelines from the Nuclear Regulatory Commission (NRC) require that the levels of Mo-99 be quantified in every Tc-99m eluate to ensure that patients receive doses that are within acceptable safety limits. High levels of this impurity can pose a significant health risk due to its own radioactive characteristics.

While aluminum and free technetium are important considerations in other contexts, they do not have the same regulatory requirement for determination as Mo-99 in regards to radionuclidic impurities in technetium eluates. Hence, our focus on Mo-99 aligns with the NRC's directive to ensure that Tc-99m products are as pure as possible with respect to this parent radionuclide.