Where is the normal biodistribution of Tc succimer (DMSA)?

• A. Heart
• B. Renal cortex
• C. Liver
• D. Bone marrow

Answer: (B)

The biodistribution of technetium-99m-labeled succimer (DMSA) is primarily in the renal cortex. DMSA is a radiopharmaceutical used in nuclear medicine, especially in renal imaging to assess the function and morphology of the kidneys. The renal cortex absorbs DMSA effectively due to its properties as a radiotracer that targets the renal tissue, allowing for clear visualization of the kidneys during imaging studies.

When DMSA is administered, its uptake is particularly concentrated in the renal cortex, where it aids in evaluating conditions such as renal scarring or obstruction. This specific localization is crucial for diagnostic purposes, especially in pediatric patients, as it facilitates the assessment of renal health and function.

In contrast, the other options represent areas where DMSA may not localize significantly or at all. For instance, while the heart, liver, and bone marrow are important organs, they do not exhibit the characteristic uptake of DMSA highlighted in its normal biodistribution profile. Thus, understanding this specific aspect of DMSA's biodistribution is vital for interpreting its role and effectiveness in nuclear medicine applications.