Where is the normal biodistribution of Tc mertiatide (MAG-3) primarily found?

• A. Heart and lungs
• B. Kidneys and bladder
• C. Liver and spleen
• D. Bone marrow

Answer: (B)

Tc mertiatide (MAG-3) is primarily utilized for renal imaging due to its specific uptake and clearance by the kidneys. Following administration, the biodistribution of MAG-3 is characterized by significant accumulation in the renal parenchyma, which includes the cortex and medulla. This is primarily due to its high extraction efficiency and is used to assess renal function and anatomy.

Subsequently, after being processed by the kidneys, MAG-3 is excreted into the renal pelvis and subsequently into the bladder. This pathway supports its strong representation in both the kidneys and the bladder when imaging is performed. The pharmacokinetics of Tc mertiatide are specifically designed to target the renal system, making this option the most accurate in relation to its normal biodistribution.

Understanding the preferred localization of radiopharmaceuticals like MAG-3 is essential for clinicians and radiologists in interpreting imaging studies effectively and determining the presence of renal abnormalities.