Journal Article

Lymphatic mapping with 99mTc-Evans Blue dye in sheep

Kollias, James, Tsopelas, Chris, Chatterton, Barry E., Shibli, Sabah, Bellon, Max, Bevington, Elaine

2008

Overview

Objective 99m Tc-Evans Blue (EB) is an agent that contains both radioactive and color signals in a single dose. Earlier studies in animal models have suggested that this agent when compared with the dual-injection technique of radiocolloid/blue dye can successfully discriminate the sentinel lymph node. The aim of this study was to investigate the potential of 99m Tc-EB as an agent to map the lymphatic system in an ovine model. Methods Doses of 99m Tc-EB (23 MBq) containing EB dye (4 mg) were administered intradermally to the limbs of four anesthetized sheep, and they were then imaged over 20–30 min using a gamma camera. The study protocol was repeated using 99m Tc-antimony trisulfide colloid (ATC) and Patent Blue V dye. The lymph nodes (popliteal, inguinal, and iliac for hind limbs or prescapular for fore limbs) were identified with a gamma probe during the operative exposure, then dissected and counted in a large volume counter. Results Simple and complex (dual) drainage patterns were visible on the scans, and the sentinel node was more radioactive than higher tier nodes in a chain, for both radiotracers. For 99m Tc-EB, maximum radioactive uptake was achieved at 3–6 min for popliteal lymph nodes, 12–14 min for iliac nodes, and 13–14 min for prescapular nodes. 99m Tc-ATC resulted in maximum radioactive uptake at 4–6 min for popliteal lymph nodes, 13 min for an inguinal node, 13–20 min for iliac nodes, and 18 min for a prescapular node. Following 99m Tc-EB injection, 15/15 lymph nodes harvested were all radioactive and blue. For 99m Tc-radiocolloid/Patent Blue V injection, 8/14 nodes were radioactive and blue, and 6/14 nodes were radioactive only. Conclusions The soluble radiotracer 99m Tc-EB appeared to be a useful lymphoscintigraphic agent in sheep, in which radioactive counts from superficial lymphatic channels and lymph nodes were sufficient for planar imaging. In comparison with 99m Tc-antimony trisulfide colloid, both tracers discriminated the sentinel lymph node up to 50 min after administration; however, 99m Tc-EB had the advantage of providing radioactive (gamma probe) and color signals simultaneously during the operative exposure.

• Publisher: Springer Japan,Springer Nature B.V
• Subject: Animals / Evans Blue / Imaging / Lymph Nodes - diagnostic imaging / Lymph Nodes - pathology / Male / Medicine / Medicine & Public Health / Nuclear Medicine / Original Article / Radiology / Radionuclide Imaging / Radiopharmaceuticals / Reproducibility of Results / Sensitivity and Specificity / Sheep / Technetium