What is the normal biodistribution of heat damaged Tc RBCs?

• A. Heart and lungs
• B. Liver and spleen
• C. Blood and muscle
• D. Kidneys and gallbladder

Answer: (B)

The normal biodistribution of heat-damaged technetium-99m (Tc) labeled red blood cells (RBCs) primarily occurs in the liver and spleen. This is due to the body's natural process of clearing damaged or aged red blood cells. When red blood cells are damaged by heat, they undergo changes that signal the reticuloendothelial system, primarily located in the liver and spleen, to recognize and remove them from circulation. As a result, when Tc RBCs are administered for imaging, those that have been heat-damaged will preferentially accumulate in these organs.

This biodistribution is significant because it enables health professionals to use Tc labeled RBCs in various diagnostic imaging procedures to assess the function of the liver and spleen or to detect any abnormalities related to the clearance of red blood cells. In contrast, other options involve organ systems that do not typically serve this role in handling damaged RBCs.