Which radiopharmaceutical would be associated with the kidneys and bladder for high doses?

• A. Tc tetrofosmin
• B. Tc exametazime (HMPAO)
• C. Tc succimer (DMSA)
• D. Tc pertechnetate

Answer: (C)

The association of Tc succimer (DMSA) with the kidneys and bladder for high doses is due to its specific mechanism of action and its biodistribution profile. DMSA is a chelating agent that selectively binds to renal tissue, allowing for evaluation of renal function and morphology. When administered, it is primarily excreted via the kidneys, and this significant renal uptake shows high doses can result in enhanced imaging of kidney function and morphology.

Technetium-99m succimer is particularly relevant in the assessment of pediatric patients for conditions like renal scarring or evaluating congenital anomalies. The reason it is chosen in this context is its ability to provide detailed imaging of the kidneys, highlighting any abnormalities or performance efficiency.

In other options, while Tc tetrofosmin and Tc exametazime are used primarily for myocardial perfusion imaging, and Tc pertechnetate is more commonly utilized for thyroid imaging or gastrointestinal studies, none of these have the same renal specificity or are indicated for high renal doses like DMSA. Thus, Tc succimer stands out as the radiopharmaceutical specifically linked to the kidneys and bladder when considering high doses for imaging purposes.