Which pathway does Tc sulfur colloid filtered follow during its normal biodistribution?

• A. Circular bloodstream
• B. Lymph drainage pathway
• C. Neural pathways
• D. Gastric pathway

Answer: (B)

The biodistribution of Tc sulfur colloid primarily follows the lymphatic drainage pathway. This is because Tc sulfur colloid is designed to be taken up by the reticuloendothelial system, particularly the liver, spleen, and lymph nodes. When injected, the colloidal particles are too large to traverse freely through the circulatory system; instead, they are preferentially trapped by macrophages and other immune cells located within the lymphatic tissues.

As the colloid moves through the lymphatic system, it can provide insights into lymphatic function and identify obstructions or abnormalities in the lymphatic drainage system, making it a valuable tool in certain diagnostic imaging procedures. This pathway enables the observation of lymphatic flow and can be used in various clinical scenarios, such as evaluating lymphedema or staging cancers that may affect lymphatic drainage.

In contrast, while other pathways may involve blood circulation or specific organ systems, they aren't the primary route for Tc sulfur colloid to demonstrate its biodistribution effectively. Hence, the significance of the lymph drainage pathway in this context underscores its role in imaging and diagnostic interpretation.