| Definition | Technetium Tc-99m tilmanocept is a radiopharmaceutical diagnostic imaging agent approved by the U.S. Food and Drug Administration (FDA) for the imaging of lymph nodes with or without scintigraphic imaging. It is a macromolecule consisting of multiple units of diethylenetriaminepentaacetic acid (DTPA) and mannose, each covalently attached to a 10 kDa dextran backbone [FDA Label]. DTPA serves as a chelating agent for technetium Tc 99m to bind [FDA Label]. Technetium Tc-99m tilmanocept is used in lymphatic mapping and lymph node localization in breast cancer, melanoma, clinically node-negative squamous cell carcinoma of the oral cavity, and other solid tumors [A32169, A32170]. Detecting sentinel lymph node (SLN) is clinically useful in the prognosis and management of the disease, as it is considered as the first lymph node that receives afferent lymphatic drainage from a primary tumor, and may be used to predict tumour staging and metastasis [A32170]. However, as nodal micrometastasis in breast cancer may not be associated with significant changes in survival, it is also important to identify clinically node-negative patients [A32170].
Technetium Tc-99m tilmanocept is a novel CD206 receptor-targeted molecule that selectively binds to mannose receptors expressed on the surface of reticuloendothelial cells in lymph nodes [A32168]. Due to its relatively small molecular weight and small molecular diameter of 7 nm [A32168], technetium Tc-99m tilmanocept displays more rapid injection site clearance, high sentinel node extraction, and low distal node accumulation compared to other conventional radiocolloids [A32170]. It achieves high overall accuracy in detecting SLN [A32169]. Once reconstituted and labelled, technetium Tc99m tilmanocept is intended to be injected in close proximity to the tumor being diagnosed and employed in preoperative gamma detection imaging in combination with various other techniques, including scintigraphy, SPECT, and SPECT/CT [L1157]. It may be administered via subcutaneous, intradermal, subareolar, or peritumoral injection, depending on the tutor location and planned injection technique [FDA Label]. It is marketed under the trade name Lymphoseek. Potential application of technetium Tc-99m tilmanocept to other cancers are being investigated [A32170]. |
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