What is the correct diluent for preparing other Tc-99m labeled products?

The correct diluent for preparing other Tc-99m labeled products is preservative-free isotonic saline. When preparing radiopharmaceuticals, it is crucial to use a diluent that does not introduce any contaminants or preservatives that could interfere with the radiopharmaceutical's efficacy or safety.

Preservative-free isotonic saline is specifically formulated to be isotonic and safe for injection, allowing proper biocompatibility when administered to patients. It helps maintain the stability and activity of the radiolabeled compound, ensuring effective imaging or therapeutic outcomes.

Using normal saline with preservatives can introduce substances that might affect the radiopharmaceutical's behavior in the body. Distilled water, while clean, does not provide the necessary isotonicity needed for safe patient administration, which may lead to complications such as hemolysis if injected intravenously. Ultrapure deionized water, although highly purified, is not isotonic and similarly poses risks when used as a diluent for intravenous preparations.

In summary, preservative-free isotonic saline ensures that Tc-99m labeled products are stable, effective, and safe for use in clinical settings.