Pentavalent DMSA Scan

A Pentavalent DMSA (Dimercaptosuccinic Acid) Scan is a nuclear medicine imaging test primarily used for detecting and evaluating medullary thyroid carcinoma (MTC) and neuroendocrine tumors. It utilizes Technetium-99m (Tc-99m) labeled pentavalent DMSA, which has an affinity for certain tumor types.

Indications for a Pentavalent DMSA Scan:

• Medullary Thyroid Carcinoma (MTC) (localization and metastasis detection)

• Neuroendocrine tumors (some cases)

• Osteosarcoma (bone tumors, though less commonly used now)

• Soft tissue sarcomas (occasionally)

Procedure:

1. Injection: A small amount of Tc-99m pentavalent DMSA is administered intravenously.

2. Waiting Period: The tracer is allowed to circulate, usually for 2–4 hours.

3. Imaging:

   • A gamma camera captures images of the distribution of the tracer.

   • SPECT/CT may be performed for more precise localization.

Results Interpretation:

• Positive Scan: Increased uptake in areas of suspected tumors or metastases.

• Negative Scan: No abnormal uptake, suggesting no detectable disease.

• Comparison with Other Scans:

  • MIBG scans (for neuroendocrine tumors).

  • FDG PET or Ga-68 DOTATATE PET (for high-sensitivity tumor detection).

Advantages of Pentavalent DMSA Scan:

✅ Useful for MTC metastasis detection.
✅ Non-invasive with good tumor affinity.
✅ Can complement other imaging modalities like CT, MRI, and PET scans.