What should be done when an eluate Sr-82 level reaches 0.01 μCi/mCi Rb-82 according to NRC regulations?

When an eluate Sr-82 level reaches 0.01 μCi/mCi Rb-82, it indicates that the concentration of strontium-82 in the rubidium-82 generator eluate has reached a threshold that is concerning according to regulatory standards set by the Nuclear Regulatory Commission (NRC). This level signifies that there is a potential contamination or migration of Sr-82 from the generator into the eluate, which poses a risk for patients receiving rubidium-82 for imaging purposes.

Stopping the use of the generator is necessary because continued use could expose patients to unacceptable levels of strontium-82, which is not the intended radionuclide for therapeutic use and could have detrimental effects on patient health. By halting the use of the generator, the facility can mitigate risks, conduct thorough evaluations, and determine the cause of the elevated strontium-82 levels, ensuring patient safety and compliance with NRC regulations.

Increasing calibration frequency, continuing usage until the next scheduled check, or reducing activity levels, while they may seem like viable responses, do not adequately address the immediate concern of unsafe Sr-82 levels in the eluate. Therefore, stopping use of the generator is the most prudent and compliant action required under these circumstances.