Radioisotope (technetium sulfur) is usually administered either by the surgeon or by the radiology department a few hours before SLNB, but it can also be administered the day before the procedure. The half-life is 6 hours, so if it is injected on the day of surgery, it is dosed at 0.5 mCi. If it is injected the day before the surgery, it is dosed at 2.5 mCi.
The 1% isosulfan blue dye or diluted methylene blue injection is usually injected about 30 minutes before surgery. Usually, 3 to 5 mL is injected.
Isosulfan blue can cause severe anaphylactic reactions, requiring resuscitation in up to 1% of cases.
Methylene blue can cause skin necrosis and pain, and in those that take serotonergic medications, it has been reported that it can cause pulmonary edema and serotonin syndrome.
Carefully search for any additional blue lymphatic channels, and remove any additional lymph nodes at the end of blue channels (lymph nodes with a blue afferent lymphatic) or any nodes that are blue themselves.
After the lymph node with the highest radioactivity is removed, reinsert the gamma probe, and remove any node with a higher count and all nodes with counts greater than 10% of the highest count.
If dual tracer is used (both radioactive dye and blue dye), remove all nodes meeting criteria for either technique.
After removing all the nodes that meet criteria by either blue dye and/or gamma counts, palpate the axilla. Any palpable suspicious nodes should be removed.
Educational aid only. Verify every dose, indication, and guideline against current institutional protocol. This is not a substitute for clinical judgment.
