Phytate technetium-99m versus dextran 500 technetium-99m in the sentinel lymph node biopsy

Area of Science:

• Nuclear medicine
• Surgical oncology
• Radiopharmacology

Background:

• Sentinel lymph node (SLN) biopsy is crucial for cancer staging.
• Radiolabeled tracers are used to identify SLNs.
• Dextran 500 99mTc and phytate 99mTc are commonly used tracers.

Purpose of the Study:

• Compare dextran 500 99mTc and phytate 99mTc for SLN biopsy.
• Determine which tracer best defines the SLN.
• Assess tracer migration to non-target lymph nodes.

Main Methods:

• Lymphoscintigraphy was performed on 32 rats divided into two groups.
• One group received dextran 500 99mTc, the other phytate 99mTc.
• Sentinel, lumbar, and inguinal lymph nodes were biopsied and analyzed for radiation using a gamma probe.

Main Results:

• Both tracers showed significantly higher counts in the SLN compared to other lymph node basins.
• No significant difference in SLN absorption was observed between dextran and phytate.
• Dextran 500 99mTc exhibited higher migration to additional lymphatic basins (1.5 basins) than phytate 99mTc (0.8 basins).

Conclusions:

• Dextran 500 99mTc and phytate 99mTc are comparable for SLN identification.
• Phytate 99mTc demonstrates reduced migration to lymph nodes beyond the SLN.
• Phytate 99mTc may offer improved specificity in SLN procedures.