What is the maximum allowable Mo-99 concentration in Tc-99m eluate at the time of administration to the patient, according to the NRC?

The maximum allowable concentration of Mo-99 in Tc-99m eluate at the time of administration to the patient is established by safety standards set by regulatory bodies such as the Nuclear Regulatory Commission (NRC). The correct answer reflects a concentration limit that ensures patient safety by minimizing the potential radiation exposure from Mo-99, which is a parent radionuclide that can contribute to unnecessary additional dose to the patient.

The specified limit of 0.15 uCi Mo-99 per 1 mCi of Tc-99m aligns with established guidelines and ensures that the amount of residual Mo-99 in the Tc-99m preparation does not exceed safety thresholds that could pose risks to patient health. Keeping Mo-99 concentrations below this threshold is crucial, as higher levels can lead to increased radioactivity and, consequently, greater radiation dose to patients, potentially increasing the risk of radiation-related side effects.

The other options present concentrations that are either too low or too high compared to established NRC limits, which helps clarify the importance of adhering to the correct regulatory standard for Mo-99 in Tc-99m preparations. Adhering to these standards is an essential aspect of quality assurance in radiopharmacy, ensuring both effective diagnostic imaging and patient safety.