Which organ receives the highest dose when using Tc RBCs?

• A. Liver
• B. Heart
• C. Spleen
• D. Kidneys

Answer: (C)

The spleen is the organ that receives the highest radiation dose when utilizing technetium-labeled red blood cells (Tc RBCs) in diagnostic imaging. This is primarily due to the spleen's key role in filtering blood and its ability to trap and sequester particles, including radiolabeled cells. When Tc RBCs are administered, a significant portion of these cells is directed to the spleen, resulting in increased radiation exposure.

In the context of blood circulation, the spleen serves as a reservoir and is involved in the removal of aged or damaged red blood cells. The properties of Tc RBCs make them particularly visible and measurable in this organ, leading to higher radiation absorption compared to other organs. Additionally, the spleen's rich blood supply enhances the delivery of radiopharmaceuticals, further contributing to the increased dose.

Understanding the biodistribution of radiopharmaceuticals like Tc RBCs helps in evaluating their safety and effectiveness in clinical settings, making it crucial to identify the organs that receive the most significant exposure during imaging procedures.