Dynamic lymphoscintigraphy in breast cancer patients: Feasibility and added value

Introduction: Lymphoscintigraphy is imaging of the lymphatic system and has been integrated into the sentinel node mapping procedures. Lymphoscintigraphy usually encompasses early or delayed static images. However, immediate dynamic imaging of the lymphatic basins and tumors has also been used as an adjunct lymphoscintigraphy imaging. The aim of this study was to assess the role of early dynamic acquisition versus static lymphoscintigraphy images for sentinel node detection in breast cancer. Methods: Seventy five women with proved breast cancer and clinically node negative axilla entered the study. For each patient 0.5 mCi Tc-99m-antimony sulfide colloid in the 0.2 cc volume was injected in periareolar region in an intradermal fashion. Immediately after injection dynamic imaging was started as 1 minute per frame for 15 minutes. Static anterior and lateral images (5min/image) was also taken 30 minutes post injection. Imaging data for each patient were evaluated blindly by two experienced nuclear physicians and early dynamic imaging data were assessed for its value in detection of sentinel nodes. Results: Overall 75 patients entered the current study. Sentinel node(s) could be identified on the dynamic lymphoscintigraphy images in 65 patients (86.6%). In 4 patients, dynamic lymphoscintigraphy could differentiate the second visible sentinel nodes as second echelon or true sentinel nodes. Conclusion: Dynamic lymphoscintigraphy immediately after radiotracer injection is feasible in breast cancer patients with a high detection rate. The added value of dynamic over delayed static imaging is the ability to differentiate between second echelon and secondary sentinel nodes.