1. ^99mTc tilmanocept or Lymphoseek is used for lymphatic mapping to identify SNL. As you should recall, these nodes trap either melanoma or breast cancer cells that shed from the primary tumor
2. Pathophysiology
   1. Once injected, it quickly travels down the lymphatic channels and arrives at the SNL within 10 minutes
   2. As a small particle, the surface contains a mannose component that has a high affinity for receptor sites that have CD 206
   3. CD 206 is found in high concentrations within macrophages and dendritic cells that occur within the SLN
   4. As tumor cells increase within the node, so do macrophages and dendritic cells
   5. Therefore, once these particles arrive at the SLN, the agent is absorbed by the lymphatic node. Lymphoseek continues down other lymphatic channels where it may encounter other Tier nodes
   6. Size of the particle ~7nm. When compared to sulfur colloid, this ranges from 0.1 to 1.0 um
   7. Manufacturer's home page contains a short video on Lymphoseek's pathology - https://www.lymphoseek.com/en_us.html
   8. Key point -tilmanocept does not attach to cancer cells but drains into nodes (SNL) and attaches or binds to the walls of the lymph node. The assumption is that where the tracer goes, so do tumor cells.
   9. The final goal is to find these SNL nodes and surgically remove them, which improve the patient outcome
   10. Understand the difference between lymphadenectomy and mastectomies
3. Procedure - Injection
   1. Similar application when compared with filtered colloid - See lecture
   2. Dose
      1. 0.5 mCi in a single volume of 0.1 mL
      2. 0.5 mCi multiple (0.1 to 0.25 mL per stick)
      3. 1.0 mCi multiple (0.2, 0.25, or 0.5 mL per stick)
   3. Suggested administrations
      1. Melanoma - intradermal or subcutaneous
      2. Breast cancer - Intradermal, subcutaneous, subareolar, or peritumoral
   4. Surgery or mapping can occur between 15 minutes to 15 hours post-dose
   5. Just like filtered colloid, a dye can also be injected along with the radiotracer
   
   6. The clinical trial shows uptake in the SNL³
4. Clinical trials
   1. Two studies were performed on a patient population. These patients either had known or suspected melanoma or breast cancer
   2. In comparison to the blue dye, when both were injected, Lymphoseek was present 100% of the time
   3. There was 0% failure in the detection SNL with Lymposeek when compared to blue dye. However, blue dye missed 25% of the SNL²
   4. One study compared Lymphoseek to filter sulfur colloid. Lymphoseek cleared faster and was equivocal in finding the SNL³
5. Other terms you should be familiar with
   1. Types of injections
   2. Tier of the SNL
   3. Use of a ⁵⁷Co flood source

References
1 - Home page for Lymphoseek - http://www.lymphoseek.com/

2 - Investigators Report Full Phase 3 Lymphoseek (Tilmanocept) Study Results At ASCO - http://www.medicalnewstoday.com/releases/227774.php

3 - Lymphoseek: A Molecular Radiopharmaceutical for Sentinel Node Detection by Wallace, AM, et al. Annals of Surgical Oncology, 10(5):531–538 http://www.researchgate.net