The Lymphatic Drainage Pattern of Internal Mammary Sentinel Lymph Node Identified by Small Particle Radiotracer ((99m)Tc-Dextran 40) in Breast / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this study was to detect the lymphatic drainage pattern of internal mammary area and verify the concept of internal mammary sentinel lymph node (IM-SLN) in breast. MATERIALS AND METHODS: A small particle radiotracer ((99m)Tc-Dextran 40) was prepared and tested. (99m)Tc-Dextran 40 was injected into intraparenchyma at the sound breast by a modified radiotracer injection technique. Subsequently, dynamic single-photon emission computed tomography (SPECT), computed tomography (CT), and SPECT/CT combination images were performed to identify the radioactive lymph vessels and internal mammary lymph nodes (IMLNs). The direction of lymph drainage and the location of the IMLNs were identified in the SPECT/CT imaging. RESULTS: The radiochemical purity of (99m)Tc-Dextran 40 was > 95%. (99m)Tc-Dextran 40 could drainage into first, second, and third lymph node and the radioactive lymph node could be detected by the γ detector in the animal experiment. After (99m)Tc-Dextran 40 injecting into intraparenchyma, 50.0% cases (15/30) were identified the drainage lymphatic vessels and radioactive IMLNs by SPECT. The drainage lymphatic vessel was found from injection point to the first IMLN (IM-SLN) after 10.5±0.35 minutes radiotracer injection, and then (99m)Tc-Dextran 40 was accumulated into the IM-SLN. The combination imaging of SPECT/CT showed the second IMLN received the lymph drainage from the IM-SLN. The lymphatic drainage was step by step in the internal mammary area. CONCLUSION: The lymph was identified to drain from different regions of the breast to IM-SLN, and then outward from IM-SLN to other IMLN consecutively. It demonstrated the concept of the IM-SLN and provided more evidences for the application of internal mammary sentinel lymph node biopsy.

A novel technique for scintigraphic visualization of internal mammary sentinel lymph nodes in breast cancer patients / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the effects of different injection techniques of radiotracer on the visualization rate of internal mammary sentinel lymph nodes (IMSLN) in breast cancer patients.</p><p><b>METHODS</b>A series of 137 consecutive breast cancer patients was included in this prospective study. Fifty-eight patients (group A) received the radiotracer (99)Tc(m)-sulphur colloid injected only into 1-2 points in the breast parenchyma in one quadrant, and seventy-nine patients (group B) received the radiotracer injection into the breast parenchyma in two quadrants of the breast. The differences of IMSLN visualization rates of the two groups were compared and the relevant affecting factors were analyzed.</p><p><b>RESULTS</b>The IMSLN visualization rate of the group B (70.9%, 56/79) was significantly higher than that of the group A (13.8%, 8/58) (P < 0.001). Both techniques seemed to be reliable to identify sentinel lymph node in the axilla (98.7% vs. 98.3%, P = 0.825). In addition, the visualization rate of internal mammary hotspots (82.2%) was more commonly seen in patients receiving injection of a larger volume of radiotracer ( ≥ 0.5 ml/point) than those receiving a smaller volume of radiotracer (<0.5 ml/point, 55.9%, P = 0.011).</p><p><b>CONCLUSIONS</b>The modified injection technique (two quadrants, large volume radiotraver, and ultrasound guidance) can significantly improve the visualization rate of IMSLN. Our findings should make the biopsy of IMSLN widely implemented and provide an effective and minimally invasive technique to evaluate the internal mammary lymph node status.</p>