RadteraLymphoscintigraphy / Sentinel Lymph Node Mapping (Tc-99m Sulfur Colloid)
NM+ ContrastWhole Body
Indications
- Sentinel lymph node identification in melanoma and breast cancer (and other cancers)
- Lymphatic drainage mapping before surgical biopsy
- Evaluation of lymphedema (lower/upper extremity)
Patient prep
- No fasting required
- Identify and mark primary tumor/biopsy site for injection planning
- Coordinate timing with surgical schedule (same-day or day-before protocols)
- Verify pregnancy status
Contrast
AgentTc-99m sulfur colloid (filtered) or Tc-99m tilmanocept (Lymphoseek)
RouteIntradermal/peritumoral/subdermal/periareolar injection (multiple small aliquots)
Dose~0.5-1 mCi total for same-day; up to ~2-5 mCi for day-before; (Lymphoseek per label)
TimingDynamic imaging immediately; static/SPECT-CT at 15 min-3 h depending on drainage
Technique
- LEHR collimator, 140 keV
- Dynamic flow imaging over injection site to track lymphatic channels
- Static planar of draining nodal basins; SPECT/CT for anatomic localization of sentinel nodes
- Skin marking of first-draining (sentinel) node(s); intraoperative gamma probe correlation
Series / Sequences
| # | Series / Sequence | Plane | Notes |
|---|---|---|---|
| 1 | Dynamic lymphatic flow | Over injection/basin | Tracks channels to sentinel node |
| 2 | Static nodal basin imaging | Anterior/oblique | Identify sentinel node(s) |
| 3 | SPECT/CT | Axial | Anatomic localization, especially head/neck, internal mammary |
Key points
- Sentinel node = first node(s) receiving drainage from tumor; mark skin for surgeon
- Combined technique: radiotracer + blue dye / intraoperative gamma probe improves detection
- Filtered Tc-99m sulfur colloid commonly used; tilmanocept (Lymphoseek) binds nodal receptors with rapid clearance
- Melanoma may have unpredictable/multiple basins; breast may drain to internal mammary nodes
References
• SNMMI Procedure Guideline for Sentinel Lymph Node Scintigraphy and Lymphoscintigraphy
• Lymphoseek (Tc-99m tilmanocept) package insert
• Radiopaedia: Lymphoscintigraphy link
• Lymphoseek (Tc-99m tilmanocept) package insert
• Radiopaedia: Lymphoscintigraphy link
Source: Researched — verify against your institution
Reference template — verify and adapt to your scanner, vendor and institution before clinical use. Not a substitute for clinical judgment.