What is the renal mechanism of localization for Tc DTPA?

• A. Reabsorption
• B. Filtration
• C. Secretion
• D. Diffusion

Answer: (B)

The renal mechanism of localization for Technetium-labeled DTPA (diethylenetriaminepentaacetic acid) is primarily through filtration. Once administered, Tc DTPA is readily cleared from the bloodstream by the kidneys. The compound is small enough to pass through the glomerular filtration barrier and enter the renal tubules, where it can be visualized via imaging techniques. This filtration process is essential because it reflects the kidneys' ability to filter blood and excrete waste products, making Tc DTPA an effective radiopharmaceutical for renal function assessment.

In the context of renal imaging, understanding the mechanism of filtration helps healthcare professionals evaluate kidney function and blood flow, as the rate of filtration correlates with the efficiency of the kidneys. Other mechanisms such as reabsorption, secretion, and diffusion may play roles in the kidney’s handling of various substances, but they are not the primary pathways for Tc DTPA localization.