What is the normal biodistribution of Tc DTPA administered intravenously?

• A. Heart and lungs
• B. Kidneys and bladder
• C. Spleen and liver
• D. Muscles and bone marrow

Answer: (B)

The normal biodistribution of Technetium-99m (Tc-99m) DTPA (diethylenetriaminepentaacetic acid) when administered intravenously typically shows significant uptake in the kidneys and subsequent excretion through the bladder. This is because Tc-99m DTPA is primarily used for renal imaging due to its properties that allow for excellent visualization of kidney function.

Upon intravenous administration, Tc-99m DTPA is filtered by the glomeruli in the kidneys, showcasing renal perfusion and functionality. The compound then passes through the renal tubules, leading to its concentration in the bladder as it is excreted in urine. This path is critical in renal studies, making the kidneys and bladder the expected organs for significant uptake and clearance of the radiopharmaceutical.

This distribution pattern is key for clinicians to assess kidney function, helping to evaluate conditions such as obstruction, renal perfusion, and overall nephron function, which are essential in the diagnosis and management of various renal pathologies.