In vivo evaluation of three different 99mTc-labelled radiopharmaceuticals for sentinel lymph node identification

Abstract

This work was designed to compare sentinel lymph node (SLN) uptake of 99mTc-labelled human serum albumin colloid (99mTc-HSAC), 99mTc-labelled antimony sulphur colloid (99mTc-SC) and a 99mTc-labelled dextran 70 solution (99mTc-Dx) and their selectivity in the identification of this node in the right rear footpad (RRF) of normal mice and tumour bearing mice. Radiopharmaceutical uptake in the SLN (popliteal lymph node) and the lumbar lymph node (LLN), the second lymphatic node station from RRF, were measured at different time points post-intradermal or intratumoural injection into the RRF of NIH normal mice and of Balb/c mice harbouring the murine mammary tumour M2. 99mTc-HSAC uptake in the SLN was significantly higher than LLN uptake. The 99mTc-SC demonstrated high uptake in SLN, but accumulation in LLN was also high. 99mTc-Dx showed low uptakes in both SLN and LLN. The intradermal injection resulted in a more effective radiopharmaceutical accumulation in SLN than did the intratumoural inoculation. Data also show that increments in tumour volume reduced radiopharmaceutical uptake in the SLN. Our results show that 99mTc-HSAC exhibits the highest uptake in the SLN combined with the smallest amounts of radiopharmaceutical passing through to the LLN. Therefore, 99mTc-HSAC appears to be the best radiopharmaceutical for sentinel node detection.

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

“…In the latter, the SLN of the footpad was always the popliteal from which the radiopharmaceutical ascends to the inguinal and lumbar lymphatic basins (7).…”

The efficacy of 99mTc-HIG for sentinel lymph node mapping in breast cancer patients

“…The rapid absorption and transport with a prolonged selective sequestration in the SLN allows accurate detection up to 24 h after injection. Spill to second-echelon nodes is minimal and non-disturbing [5,6,14,[21][22][23][24][25]. 99m Tc-HIG is a successful and promising new agent for visualizing the lymphatic system.…”

The sentinel node in breast cancer

“…The colloid employed should be of a size to be taken up efficiently and retained within the sentinel node. It has been shown that the highest counts in recovered sentinel nodes were from 100 to 200 nm albumin colloid particles [31] . Filtered 99m Tc-sulphur colloid (100 nm filtered) has a faster transport rate to the regional nodes and lower radiation dosimetry.…”