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Updated: Jan 1, 2026
A Practical Guide for the Production and PET/CT Imaging of 68Ga-DOTATATE for Neuroendocrine Tumors in Daily Clinical Practice
Published on: April 17, 2019
Lower 68 Ga-DOTATOC uptake in nonfunctioning pituitary neuroendocrine tumours compared to normal pituitary gland-A
Axel Tjörnstrand1,2, Olivera Casar-Borota3,4, Kerstin Heurling5,6
1Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.
Objectives:
68 Ga-DOTATOC PET targets somatostatin receptors (SSTRs) and is well established for the detection of SSTR-expressing tumors, such as gastrointestinal neuroendocrine tumors. Pituitary adenomas, recently designated as pituitary neuroendocrine tumors (PitNETs), also express SSTRs, but there has been no previous evaluations of 68 Ga-DOTATOC PET in PitNET patients. The aim of this pilot study was to evaluate the diagnostic properties of 68 Ga-DOTATOC PET in the most common PitNET, ie non-functioning (NF)-PitNET.
Design/Patients:
NF-PitNET patients (n = 9) and controls (n = 13) were examined preoperatively with 68 Ga-DOTATOC PET for 45 min after tracer injection in dynamic list mode. Tumor specimens were collected during surgery in patients. MRI and PET images were co-registered using PMOD software. The maximum standard uptake value (SUVmax ) was analyzed in manually outlined regions of interest (ROI) around the tumor in patients and around the pituitary gland in controls. Immunohistochemical analyses were conducted on tumor specimens for assessment of tumor cell type and SSTR expression.
Results:
Median SUVmax (IQR) was lower in patients than in controls (3.9 [3.4-8.5] vs 14.1 [12.5-15.9]; P < .01]. In ROC analysis, the area under the curve was 0.87 (P < .01) for SUVmax , with 78% sensitivity and 92% specificity. Immunohistochemical analysis showed NF-PitNETs were of gonadotroph (n = 7) and corticotroph (n = 2) origin. SSTR expression was high for SSTR3, low-to-moderate for SSTR2, and low for SSTR1 and SSTR5.
Conclusions:
This proof-of-concept study shows that 68 Ga-DOTATOC PET can be used to differentiate between normal pituitary tissue and NF-PitNET.
Insights
This pilot study demonstrates that Gallium-68 DOTATOC PET imaging can effectively differentiate non-functioning pituitary neuroendocrine tumors (NF-PitNETs) from normal pituitary tissue. The imaging technique shows promising diagnostic accuracy for these SSTR-expressing tumors.
Area of Science:
- Nuclear Medicine
- Oncology
- Endocrinology
Background:
- Gallium-68 DOTATOC PET (68Ga-DOTATOC PET) is established for detecting somatostatin receptor (SSTR)-expressing tumors.
- Pituitary neuroendocrine tumors (PitNETs) express SSTRs, but 68Ga-DOTATOC PET has not been previously evaluated in these patients.
- Non-functioning PitNETs (NF-PitNETs) are the most common type of PitNET.
Purpose of the Study:
- To evaluate the diagnostic performance of 68Ga-DOTATOC PET in patients with NF-PitNET.
- To assess the ability of 68Ga-DOTATOC PET to differentiate NF-PitNETs from normal pituitary tissue.
Main Methods:
- A pilot study involving 9 NF-PitNET patients and 13 controls examined preoperatively using dynamic 68Ga-DOTATOC PET.
- Tumor specimens were analyzed for cell type and SSTR expression via immunohistochemistry.
- 68Ga-DOTATOC PET images were co-registered with MRI, and maximum standard uptake values (SUVmax) were analyzed.
Main Results:
- Median SUVmax was significantly lower in NF-PitNET patients compared to controls (3.9 vs 14.1, P < .01).
- 68Ga-DOTATOC PET demonstrated an area under the ROC curve of 0.87 (P < .01), with 78% sensitivity and 92% specificity for differentiating NF-PitNETs.
- Immunohistochemistry revealed NF-PitNETs were primarily of gonadotroph and corticotroph origin with varying SSTR expression levels.
Conclusions:
- 68Ga-DOTATOC PET imaging is a viable tool for differentiating NF-PitNETs from normal pituitary tissue.
- This proof-of-concept study supports the use of 68Ga-DOTATOC PET in the diagnostic workup of NF-PitNETs.
