If 99mTc exametazime is prepared at 0900, by what time should it be used?

In nuclear medicine, the radiopharmaceutical 99mTc exametazime, commonly used for imaging and evaluating certain conditions, has a half-life of about six hours. This characteristic determines how long after preparation the radiotracer remains viable and effective for use.

After preparation at 0900, the activity of the radiopharmaceutical will begin to decay. Generally, it's recommended to use prepared radiopharmaceuticals within a few hours to ensure optimal imaging results. In this case, the correct time frame to use the preparation is around four hours post-preparation, which would place the effective use time at approximately 1300.

This timeline ensures that the dose provides sufficient radiation for imaging while achieving high quality and minimizing patient exposure to lower activity levels. Using the radiopharmaceutical too late could lead to insufficient imaging capability, making it less effective or even ineffective for the diagnostic purpose intended.