99mTc-aprotinin: a new tracer for kidney morphology and function

Area of Science:

• Nuclear Medicine
• Nephrology
• Radiopharmacology

Background:

• Aprotinin (Ap) is a protease inhibitor that accumulates in the kidneys.
• Renal imaging agents are crucial for diagnosing and monitoring kidney disease.

Purpose of the Study:

• To evaluate the efficacy of technetium-99m-labeled aprotinin (99mTc-Ap) for renal imaging in patients with varying degrees of renal impairment.
• To compare the performance of 99mTc-Ap with technetium-99m-labeled dimercaptosuccinic acid (99mTc-DMSA).
• To investigate the pharmacokinetics and renal function assessment capabilities of 99mTc-Ap.

Main Methods:

• Renal scans were performed using 99mTc-Ap in 112 adult patients with renal disease.
• A comparison of 99mTc-Ap and 99mTc-DMSA renal scans was conducted in 20 patients with renal failure.
• Pharmacokinetic studies, including plasma clearance and urinary excretion, were performed in a subset of patients.

Main Results:

• Highly satisfactory renal scans were achieved in all patients using 99mTc-Ap.
• 99mTc-Ap demonstrated slightly superior performance to 99mTc-DMSA, particularly in advanced renal failure.
• Plasma clearance of 99mTc-Ap correlated well with glomerular filtration rate (GFR), and urinary excretion was negligible.

Conclusions:

• Technetium-99m-labeled aprotinin (99mTc-Ap) is an excellent radiopharmaceutical for renal imaging.
• 99mTc-Ap shows significant promise for evaluating renal function, especially in patients with impaired kidney function.
• The agent's stability and low urinary excretion contribute to its effectiveness in renal scintigraphy.