Nephrotoxicity in mice after repeated imaging using 111In-labeled peptides

Area of Science:

• Nuclear Medicine
• Radiopharmaceutical Therapy
• Toxicology

Background:

• Indium-111 ((111)In)-labeled peptides are used in SPECT imaging.
• Assessing renal radiation dose and toxicity is crucial for patient safety.

Purpose of the Study:

• To determine the renal radiation dose of various (111)In-labeled peptides using animal SPECT.
• To evaluate potential renal toxicity and long-term nephrotoxic effects.

Main Methods:

• Wild-type and megalin-deficient mice underwent repeated SPECT imaging after injection of (111)In-labeled peptides.
• Renal retention, absorbed kidney radiation doses, body weight, renal function, and histology were assessed.

Main Results:

• (111)In-diethylenetriaminepentaacetic acid-exendin-4 resulted in a 70-Gy kidney dose in wild-type mice, with megalin-deficient kidneys receiving 20-40 Gy.
• Other peptides yielded lower renal doses.
• Imaged animals showed indications of renal damage.

Conclusions:

• Micro-SPECT allows for longitudinal studies in individual animals.
• High renal radiation doses from (111)In-labeled radiotracers may induce long-term nephrotoxicity.