RadteraSomatostatin Receptor Imaging (Ga-68 DOTATATE PET/CT; legacy In-111 Octreotide)
PET+ ContrastWhole Body
Indications
- Localization and staging of somatostatin-receptor-positive neuroendocrine tumors (NETs)
- Detection of primary, metastatic, and recurrent NETs
- Patient selection for peptide receptor radionuclide therapy (Lu-177 DOTATATE)
- Restaging / treatment response
Patient prep
- No fasting required for Ga-68 DOTATATE
- Hold long-acting somatostatin analogs (e.g., octreotide LAR/lanreotide) ~3-4 weeks before scan; short-acting ~24 h (may compete for receptors)
- Hydration; void before imaging
- Verify pregnancy status
Contrast
AgentGa-68 DOTATATE (NETSPOT) or Ga-68 DOTATOC; legacy In-111 pentetreotide (OctreoScan)
RouteIV
DoseGa-68 DOTATATE 4-5 mCi (148-185 MBq); In-111 pentetreotide ~6 mCi (222 MBq)
TimingGa-68 DOTATATE uptake ~40-90 min (typ. 60 min); In-111 octreotide imaging at 4 and 24 h (+/- 48 h)
Technique
- PET/CT for Ga-68 DOTATATE: skull base to mid-thigh (or vertex to feet); low-dose CT for AC/localization
- In-111 octreotide: medium-energy collimator, planar whole-body + SPECT/CT at 4 and 24 h
- Quantitative SUV available with PET
Series / Sequences
| # | Series / Sequence | Plane | Notes |
|---|---|---|---|
| 1 | Whole-body PET/CT (Ga-68 DOTATATE) | Axial/multiplanar | ~60 min uptake; superior sensitivity, shorter exam |
| 2 | Planar + SPECT/CT (In-111 octreotide) | Whole body / axial | 4 h and 24 h imaging (legacy) |
Key points
- Ga-68 DOTATATE PET/CT has largely replaced In-111 OctreoScan (higher sensitivity, lower dose, faster, quantitative)
- Hold long-acting somatostatin analogs to avoid receptor blockade / reduced tumor uptake
- Physiologic uptake in spleen, kidneys, adrenals, pituitary, liver, uncinate pancreas (potential pitfall)
- Positive scan supports eligibility for Lu-177 DOTATATE therapy
References
• SNMMI Procedure Standard/EANM Practice Guideline for SSTR PET (J Nucl Med 2023;64:204)
• NETSPOT (Ga-68 DOTATATE) package insert
• Radiopaedia: DOTATATE PET link
• NETSPOT (Ga-68 DOTATATE) package insert
• Radiopaedia: DOTATATE PET 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.