Technetium-99m labeling of polymorphonuclear leukocytes: preparation with two different stannous agents

Area of Science:

• Nuclear Medicine
• Cell Biology
• Radiopharmacy

Background:

• Accurate imaging of inflammatory lesions requires effective labeling of autologous cells.
• Current methods for labeling human polymorphonuclear leukocytes (PMNs) with Technetium-99m (Tc-99m) may impact cell function or labeling efficiency.

Purpose of the Study:

• To develop and optimize an in vitro technique for labeling human polymorphonuclear leukocytes (PMNs) with Tc-99m.
• To assess the efficiency, cell viability, and diagnostic potential of the developed Tc-99m labeling method for PMNs.

Main Methods:

• Titration of stannous fluoride and stannous pyrophosphate for optimal "pretinning" of PMNs.
• Isolation of PMNs from 100 ml of blood followed by labeling with 10-15 mCi Tc-99m.
• Washing of cell suspensions and assessment of cell-bound activity, cell function, sterility, and endotoxin levels.

Main Results:

• Optimal stannous agent concentrations were determined for efficient PMN labeling.
• Labeling yields ranged from 1.6-4.8 mCi (20.5-33.5% of added tracer) after three washes.
• Cell-bound activity was high (92.3% +/- 1.9), and cell function remained unimpaired. Sterility and endotoxin exclusion were confirmed.

Conclusions:

• An effective and reproducible in vitro method for Tc-99m labeling of human PMNs has been established.
• The technique preserves PMN function and ensures product safety, making it suitable for diagnostic applications.
• This method holds promise for scintigraphic imaging of acute inflammatory lesions using autologous labeled leukocytes.