When is SPECT liver imaging with 99mTc sulfur colloid typically performed?

SPECT liver imaging using 99mTc sulfur colloid is typically performed 10-15 minutes after the tracer administration because that timeframe allows for optimal distribution of the radiotracer within the liver. After injection, the sulfur colloid rapidly localizes in the reticuloendothelial cells of the liver, and imaging at this time captures the best functional information about hepatic uptake.

During the initial moments post-injection, insufficient imaging may occur as the tracer has not yet fully accumulated in the liver or might still be in transit. Waiting too long, such as 30-60 minutes or beyond, may not provide the best representation of liver function and can introduce factors like shifting of the tracer out of the liver or dilution into surrounding tissues.

Therefore, the 10-15 minute window is crucial for obtaining high-quality images that reflect the liver's anatomy and physiological function effectively.