Labeling In-111 WBC

•  Used for localizing infection and abscesses

•  Principle of labeling

  •   In-111 Oxine is lipophilic and crosses lipid bilayer of cell membranes

  •   Inside the cell the Oxine complex is broken down and the resulting charged In-111 species is trapped in the cell

  •   All cell types are labeled so prior leukocyte separation is necessary

In-111 WBC Labeling Procedure

1. Check patient’s WBC count; adjust if necessary

2. Separate WBC fraction as previously described

3. Add 500-1000 µCi In-111 Oxine.

4. Radiolabel as previously described. Labeling typically 50-95%.

5. QC is the same as for Tc-99m WBC
   

• WBC Separation by Osmotic Lysis

  • RBCs are more susceptible to lysis from osmotic pressure than WBCs

  • Add sterile H₂O to WBC pellet contaminated w/ RBCs

    • This lowers the concentration of ions, etc.

    • The result is increased pressure in cells  

    • RBCs lyse (burst open and die)  

6. Quickly add 5% NaCl to restore tonicity

7. Centrifuge

8. WBC sediment, Platelets and RBC debris remain in supernatant

9. Remove supernatant

10. Resuspend WBC

11. Label WBC with Tc-99m or In-111

Labeled Platelets

• Separate platelets from whole blood by centrifugation

• Label by incubation with lipophilic complexes of Tc-99m or In-111

Uses

• Localization of thrombi

• Platelet survival studies