How long can Tc-99m labeled compounds remain usable after preparation?

How long can Tc-99m labeled compounds remain usable after preparation?

• A. 1 hour
• B. 12 hours
• C. 6 hours
• D. 24 hours

Answer: (C)

Tc-99m labeled compounds typically remain usable for about 6 hours after preparation. This timeframe is critical for ensuring that the radiopharmaceutical maintains its efficacy and safety for diagnostic imaging procedures. The diminished stability beyond this duration can result in a significant decrease in radioactivity and potentially affect image quality, leading to diagnostic inaccuracies. This limitation is due to the half-life of Tc-99m, which is approximately 6 hours, meaning that after this time, the radioactivity of the compound decreases to approximately half of its initial value. Therefore, for optimal imaging results, it is essential that these compounds are used within this time frame. This is why the correct answer emphasizes a 6-hour usability window.

Tc-99m labeled compounds typically remain usable for about 6 hours after preparation. This timeframe is critical for ensuring that the radiopharmaceutical maintains its efficacy and safety for diagnostic imaging procedures. The diminished stability beyond this duration can result in a significant decrease in radioactivity and potentially affect image quality, leading to diagnostic inaccuracies.

This limitation is due to the half-life of Tc-99m, which is approximately 6 hours, meaning that after this time, the radioactivity of the compound decreases to approximately half of its initial value. Therefore, for optimal imaging results, it is essential that these compounds are used within this time frame. This is why the correct answer emphasizes a 6-hour usability window.