A patient with a known NET (neuroendocrine tumour) of the pancreas undergoes 68Ga-DOTATATE PET-CT. This tracer targets which receptor and what is its main advantage over 18F-FDG PET-CT for NETs?
- A Targets somatostatin receptor (SSTR2); superior sensitivity for well-differentiated/low-grade NETs which are FDG-negative ✓
- B Targets dopamine D2 receptor; superior for high-grade NETs
- C Targets VEGF receptor; used for antiangiogenic therapy response
- D Targets folate receptor; superior for pancreatic ductal adenocarcinoma
Correct answer: A. Targets somatostatin receptor (SSTR2); superior sensitivity for well-differentiated/low-grade NETs which are FDG-negative
Explanation
68Ga-DOTATATE (and 68Ga-DOTATOC) targets somatostatin receptor type 2 (SSTR2), which is overexpressed on well-differentiated, low-grade neuroendocrine tumours. These low-grade NETs are typically FDG-negative (low glucose metabolism) and are well-detected by somatostatin receptor imaging. In contrast, high-grade/poorly differentiated NETs have high FDG avidity but may lose SSTR expression ('flip-flop' phenomenon). 68Ga-DOTATATE has >95% sensitivity for SSTR-positive NETs, superior to octreotide scintigraphy.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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