Influence of colloid particle profile on sentinel lymph node uptake

Introduction: Particle size of colloids employed for sentinel lymph node (LN) detection is not well studied. This investigation aimed to correlate particle size and distribution of different products with LN uptake.Methods: All agents (colloidal tin, dextran, phytate and colloidal rhenium sulfide) were labeled with (99m)Tc according to manufacturer's instructions. Sizing of particles was carried out oil electron micrographs using Image Tool for Windows (Version 2.0). Biodistribution studies in main excretion organs as well as in popliteal LN were Performed in male Wistar rats [30 and 90 min post injection (p.i.)]. the injected dose was 0.1 ml (37 MBq) in the footpad of the left posterior limb. Dynamic images (0-15 min p.i.) as well as static ones (30 and 90 min) were acquired in gamma camera.Results: Popliteal LN was clearly reached by all products. Nevertheless, particle size remarkably influenced node uptake. Colloidal rhenium sulfide, with the smallest diameter (5.1 x 10(-3)+/- 3.9x10(-3) mu m), permitted the best result [2.72 +/- 0.64 percent injected dose (%ID) at 90 min]. Phytate displayed small particles (