Sentinel lymph node uptake of two different technetium-labeled radiocolloids,

Area of Science:

• Nuclear medicine
• Radiopharmacology
• Lymphatic imaging

Background:

• Sentinel lymph node (SLN) biopsy is crucial for cancer staging.
• Accurate SLN identification relies on effective radiotracer uptake.
• Comparing radiotracers is essential for optimizing SLN detection.

Purpose of the Study:

• To compare the uptake efficiency of technetium-99m-labeled human serum albumin ([99mTc]HSA) and technetium-99m-labeled sulfur colloid ([99mTc]SC) in sentinel lymph nodes (SLNs).

Main Methods:

• Radiocolloid levels of [99mTc]SC and [99mTc]HSA were quantified in SLNs, other lymph nodes (femoral, ischial), spleen, and injection site over 240 minutes.
• Injections were administered into the rear footpad of C57 BL/6 mice.

Main Results:

• [99mTc]SC demonstrated significantly higher radioactive counts in SLNs compared to [99mTc]HSA (p < 0.001).
• [99mTc]HSA showed higher uptake in subsequent lymph nodes (FLN) and the spleen.
• [99mTc]SC exhibited rapid uptake and retention at the injection site and SLN.

Conclusions:

• [99mTc]SC is rapidly taken up by lymphatics and retained efficiently in SLNs.
• [99mTc]HSA disperses more rapidly to secondary lymph nodes and systemic circulation.
• [99mTc]SC is likely a superior radiocolloid for intraoperative sentinel lymph node detection.