# Technetium Tc-99m sulfur colloid

Source: https://onco.cc/drugs/technetium-sulfur-colloid/  
OnCo record `technetium-sulfur-colloid` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Technetium sulfur colloid is the radioactive tracer injected around a breast cancer or melanoma before surgery so the surgeon can find the first lymph node the tumour drains to and remove only that node instead of the whole basin.

## Summary

Technetium-99m sulfur colloid has been used for liver, spleen and bone marrow scintigraphy since the 1970s, and the FDA label was extended to lymphatic mapping to localise lymph nodes draining a primary breast tumour or melanoma. Sentinel node biopsy guided by the tracer, often with blue dye, replaced routine axillary dissection in breast cancer and elective node dissection in melanoma after the NSABP B-32 and MSLT-I trials, sparing most patients lymphoedema. Tilmanocept (Lymphoseek), a purpose-designed mannose receptor agent, is the newer alternative.

## Fields

- Kind: Treatment
- Status: established
- Last checked: 2026-09-08
- Also known as: Tc-99m sulphur colloid
- Tags: gap-fill; chembl-universe
- Brand: Technetium Tc 99m Sulfur Colloid Kit
- Modality: Radiopharmaceutical for lymphatic mapping and liver, spleen and marrow imaging
- Mechanism: Colloidal particles labelled with technetium-99m are taken up by macrophages; injected near a tumour they drain to and lodge in the first (sentinel) lymph nodes, which a gamma probe then finds during surgery.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Technetium_(99mTc)_sulfur_colloid
- Wikipedia: https://en.wikipedia.org/wiki/Technetium_(99mTc)_sulfur_colloid
- Label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=technetium%20tc%2099m%20sulfur%20colloid

## Connected records

- cancers: [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [Melanoma](https://onco.cc/cancers/melanoma/)
- technologies: [Sentinel lymph node biopsy](https://onco.cc/technologies/sentinel-node/)

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