When using heat damaged Tc RBCs, which organ receives the highest dose?

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

Answer: (C)

When using heat-damaged technetium-labeled red blood cells (RBCs), the spleen receives the highest dose primarily due to its role in filtering and eliminating damaged or aged red blood cells from circulation. The spleen is particularly adept at recognizing and sequestering these altered cells, as it plays a critical role in the phagocytosis of damaged or defective red blood cells.

Heat damage can alter the morphology and membrane integrity of RBCs, making them more recognizable to the splenic macrophages, which leads to an increased accumulation of these cells in the spleen. As a result, the dose of radiation delivered to the spleen is significantly higher compared to other organs, which may not engage in the same level of filtration and clearance of these altered cells.

In contrast, the heart, kidneys, and liver do not engage in the same primary function of filtering aged or damaged RBCs; thus, they receive a relatively lower dose in this scenario. The physiological and functional specifics of each organ dictate their levels of exposure when heat-damaged technetium-labeled RBCs are introduced into the system.