Distribution of dextran-99mTc and activated carbon in sentinel lymph nodes of rabbits [Abstract in English]

Rogério Porto da Rocha, Elke Lusmöller Porto da Rocha, Leda Viegas de Carvalho, Ewaldo Bolivar de Souza Pinto, Rodrigo P. M. de Souza


Aims: To determine the distribution of dextran- 9mTc in the sentinel lymph node (SLN), and whether activated carbon tends to concentrate more on one side of the SLN and thus could be utilized as an intraoperative marker.
Methods: Sixteen rabbits of New Zealand breed were utilized, with ages ranging from three to six months. They underwent administration of 0.1 ml of dextran-99mTc on the plantar face of the right hind paw, 20 minutes prior to SLN biopsy. One ml of a solution containing 3% activated carbon and patent blue V in the proportions 1:1 was then injected close to the dextran-99mTc injection site. Twenty minutes later, the radioactivity was measured at the injection site and at the popliteal fossa to confirm the time taken for dextran- 9mTc to migrate, and for subsequent comparison with the SLN radioactivity levels. The lymph node identified was resected and the points of greatest (H1) and least (H2) radioactivity uptake were measured.
Results: Formation of two papules derived from the injections of dextran-99mTc and patent blue V plus activated carbon was observed, thus proving the occurrence of effective lymphatic circulation during the period between application of the dye and SLN dissection. The mean uptakes in the H1 and H2 halves of the SLN were 6139 I/s and 4549 I/s, respectively.
Conclusions: Analysis of the radioactivity in the resected SLN suggested that greater dextran-99mTc uptake occurred in just one of its halves. Activated carbon can be utilized as an intraoperative method for identifying the SLN.

e-ISSN: 1980-6108 | ISSN-L: 1806-5562

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