Lymphoscintigraphy

Lymphoscintigraphy

Lymphoscintigraphy is a nuclear medicine imaging technique used to evaluate the lymphatic system. It helps identify lymphatic drainage patterns, lymph node function, and obstructions in lymphatic flow. The test is commonly used for sentinel lymph node mapping, detecting lymphedema, and assessing lymphatic disorders.

Indications for Lymphoscintigraphy:

✅ Sentinel Lymph Node Mapping

• Breast cancer (identifying the first lymph node draining the tumor).

• Melanoma (to guide surgical lymph node removal).

✅ Lymphedema Diagnosis

• Primary lymphedema (congenital lymphatic system defects).

• Secondary lymphedema (due to cancer surgery, radiation, or infections like filariasis).

✅ Lymphatic Obstruction or Leakage

• Chylothorax or chylous ascites (lymphatic fluid leakage into the chest or abdomen).

• Lymphatic malformations (congenital disorders affecting lymph flow).

Procedure:

1. Injection of Radiotracer:

   • A small amount of Technetium-99m (Tc-99m) sulfur colloid or Tc-99m filtered sulfur colloid is injected intradermally (into the skin) near the affected area (e.g., foot, hand, or tumor site).

2. Imaging with Gamma Camera:

   • Dynamic images are taken to track real-time lymphatic flow.

   • Delayed static images (at 1-2 hours) assess lymph node uptake and drainage.

   • SPECT/CT may be used for precise localization.

3. Interpretation of Results:

   • Normal: Smooth lymphatic drainage and symmetric uptake in regional lymph nodes.

   • Obstruction: Delayed or absent lymphatic flow.

   • Lymphedema: Slow or absent tracer movement with dermal backflow.

   • Sentinel Node Identification: The first lymph node(s) showing uptake, guiding biopsy or removal.

Advantages of Lymphoscintigraphy:

✅ Non-invasive and safe (low radiation exposure).
✅ Accurately identifies sentinel lymph nodes before surgery.
✅ Detects lymphatic dysfunction in early lymphedema.