The Tc sulfur colloid normal distribution indicates what percentage in the bone marrow?

• A. 2%
• B. 5%
• C. 10%
• D. 15%

Answer: (B)

In the context of imaging using technetium-99m sulfur colloid, the distribution of the radiopharmaceutical throughout the body provides important insights into various physiological processes. Specifically, the normal distribution indicates that approximately 5% of the administered dose will typically be localized in the bone marrow. This is significant because it reflects the spleen and liver's primary role in reticuloendothelial system imaging, while the bone marrow's uptake can provide information about hematopoietic activity and bone health.

Understanding the typical distribution percentages is crucial for interpreting imaging results accurately. A 5% allocation in the bone marrow helps clinicians consider how much of the radiopharmaceutical is involved in assessing bone marrow function compared to other organs, aiding in differential diagnosis and treatment planning.