Localizing infection with a technetium-99m-labeled peptide: initial results.

Area of Science:

• Nuclear Medicine
• Radiopharmacology
• Infectious Disease Imaging

Background:

• In vitro-labeled leukocyte imaging is a standard for infection detection.
• An in vivo labeling method is highly desirable for improved efficiency and patient care.

Purpose of the Study:

• To evaluate the safety and efficacy of a leukocyte-avid peptide (P483H) for in vivo infection detection.
• To determine the impact of peptide dose on imaging performance.
• To compare the diagnostic accuracy of P483H with in vitro-labeled leukocyte scintigraphy.

Main Methods:

• A 23-amino acid peptide (P483) was labeled with 99mTc and complexed with heparin (P483H).
• Thirty patients received varying doses of 99mTc-P483H and were imaged at 15 min and 90-120 min.
• Twenty patients also underwent (111)In-labeled leukocyte scintigraphy for comparison.

Main Results:

• The 99mTc-P483H peptide imaging agent was safe, with all adverse events being mild and self-resolving.
• Sensitivity, specificity, and accuracy for P483H were 0.86, 0.81, and 0.83, respectively, with no improvement from combined early/late imaging.
• No dose-dependent relationship was observed, and P483H accuracy was identical (0.80) to in vitro-labeled leukocyte imaging in a subset of patients.

Conclusions:

• 99mTc-P483H provides a safe, rapid, and accurate method for focal infection detection.
• The diagnostic performance of 99mTc-P483H is comparable to established in vitro-labeled leukocyte imaging.
• This in vivo peptide-based imaging agent warrants further clinical investigation.