How long after administration should imaging typically begin for tumor imaging?

For tumor imaging using Positron Emission Tomography (PET), imaging typically begins 5-10 minutes after the administration of the radiotracer. This timing is crucial as it allows the tracer to adequately distribute and localize within the tissues of interest, including tumors.

In this timeframe, the radiotracer, which is often a glucose analog like fluorodeoxyglucose (FDG), has sufficient time to be taken up by cells that are metabolically active, such as tumor cells. These cells will show increased uptake of the tracer compared to normal tissues, enhancing the contrast in the imaging results.

Starting the imaging too soon, such as at 1 minute, may not provide the optimal distribution profile needed for accurate tumor detection. Additionally, waiting too long, such as 15 or 30 minutes, can increase background activity from normal tissues as they also take up the tracer, potentially making it more challenging to identify tumors with precision.

Thus, the 5-10 minute window strikes an appropriate balance for capturing the most accurate images of metabolic activity in tumors, ensuring that the PET scan is effective for diagnostic purposes.