Experimental study of ^99mTc-aluminum oxide use for sentinel lymph nodes detection

The purpose of the study was a comparative research in the possibility of using the radiopharmaceuticals ^99mTc-Al₂O₃ and ^99mTc-Nanocis for visualizing sentinel lymph nodes. The measurement of the sizes of ^99mTc-Al₂O₃ and ^99mTc-Nanocis colloidal particles was performed in seven series of radiopharmaceuticals. The pharmacokinetics of ^99mTc-Al₂O₃ and ^99mTc-Nanocis was researched on 50 white male rats. The possibility of the use of ^99mTc-Al₂O₃ and ^99mTc-Nanocis for lymphoscintigraphy was studied in the experiments on 12 white male rats. The average dynamic diameter of the sol particle was 52-77 nm for ^99mTc-Al₂O₃ and 16.7-24.5 nm for ^99mTc-Nanocis. Radiopharmaceuticals accumulated in the inguinal lymph node in 1 hour after administration; the average uptake of ⁹⁹mTc-Al₂O₃ was 8.6% in it, and the accumulation of ^99mTc-Nanocis was significantly lower - 1.8% (p < 0.05). In all study points the average uptake of ^99mTc-Al₂O₃ in the lymph node was significantly higher than ^99mTc-Nanocis accumulation. The results of dynamic scintigraphic studies in rats showed that ^99mTc-Al₂O₃ and ^99mTc-Nanocis actively accumulated into the lymphatic system. By using ^99mTc-Al₂O₃ inguinal lymph node was determined in 5 minutes after injection and clearly visualized in all the animals in the 15th minute, when the accumulation became more than 1% of the administered dose. Further observation indicated that the ^99mTc-Al₂O₃ accumulation reached a plateau in a lymph node (average 10.5%) during 2-hour study and then its accumulation remained practically at the same level, slightly increasing to 12% in 24 hours. In case of ^99mTc-Nanocis inguinal lymph node was visualized in all animals for 15 min when it was accumulated on the average 1.03% of the administered dose. Plateau of ^99mTc-Nanocis accumulation in the lymph node (average 2.05%) occurred after 2 hours of the study and remained almost on the same level (in average 2.3%) for 24 hours. Thus, the experimental study of a new domestic radiopharmaceutical showed that the ^99mTc-Al₂O₃ accumulates actively in the lymph nodes several times as compared to the imported analogue and its practical application will facilitate intraoperative identification of sentinel lymph nodes.