Combining dose and injection volume for good performance of a specific radiopharmaceutical for sentinel node detection.

Núñez, Eutimio Gustavo Fernández; de Oliveira, Erica Aparecida; da Silva, Natanael Gomes; Filho, Renato Santos de Oliveira

INTRODUCTION The aim of this work was to quantify the effects of injection volume at different technetium-99m specific radiotracer doses on its lymphatic movement in animal model. PROCEDURES Effects of injection volume (50, 100 μl) at different doses (0.05, 0.135, 0.22 nmol) on popliteal node (PN) detection were studied in rats. The radiotracer under study was (99m)Technetium-cysteine-mannose-dextran conjugate (30 kDa). RESULTS At 0.05 nmol dose, higher PN uptake was observed at 50 μl injection volume (2.6 fold increase). Conversely, at 0.135 nmol dose, an increase of radiotracer retention in PN was achieved at 100 μl volume, 78% higher than 50 μl. However, at 0.22 nmol dose, the injection volume changes did not influence on the PN uptake. Considering as suitable radiotracer performance: high PN uptake and extraction, better combinations were 0.05 nmol/50 μl, 0.135 nmol/100 μl, 0.22/50 μl. CONCLUSION Suitable performances could be reached by proper combinations of dose, injection volume and concentration for a specific radiotracer used in sentinel lymph node detection.