Table 1 Present direct radioisotopic cell labeling methods

¹¹¹In-oxine/67.4 h

Leukocytes

Approximately 80% cell labeling yield in 30 min

[2-6]

Lymphocytes

Significant efflux rate reported in lymphocytes (approximately 70% effluxed in 24 h) and HPCs (approximately 75% effluxed in 96 h)

HPCs

Suboptimal image quality and sensitivity

⁶⁴Cu-PTSM/12.7 h

C6 glioma cells

70% to 85% cell labeling yield in 5 h

[7]

Significant efflux rate from cells (approximately 80% effluxed in 24 h)

⁶⁴Cu-TETA- or ⁸⁹Zr-DFO-antiCD45/12.7 h (⁶⁴Cu), 78.4 h (⁸⁹Zr)

hPBSCs

Binds to only CD45 membrane protein expressing cells

[8]

Approach was suboptimal possibly due to insufficient CD45 molecules on the plasma membrane of stem cells

⁸⁹Zr-oxine/78.4 h

Myeloma cells and natural killer cells

Approximately 32% cell labeling yield in 30 min

[9,10]

Significant efflux rate reported for myeloma cells (29% effluxed in 24 h) and natural killer cells (70% to 80% effluxed in 7 days)

Loss of cell viability possibly due to oxine exposure

⁸⁹Zr-protamine sulfate/78.4 h

Dendritic cells and T lymphocytes

Approximately 34% cell labeling yield (dendritic cells) in 30 min

[11]

Approximately 12% cell labeling yield (T lymphocytes) in 30 min

Weakly binds to non-specific intracellular biomolecules

Efflux rate not reported