SiTATE
A fluorine-18 octreotate tracer that maps neuroendocrine tumours and meningiomas by their somatostatin receptors
SiTATE is a somatostatin-like peptide built to carry radioactive fluorine-18 to tumours that display somatostatin receptors, so a PET scan can show where they are. Its trick is chemical: a silicon fluoride acceptor group swaps an ordinary fluorine atom for a radioactive one in a single gentle step. That makes it easier to produce in quantity than the gallium-68 tracers in routine use. Studies, mostly from German hospitals, have used it in neuroendocrine tumours, meningiomas and other receptor-rich cancers. It is not approved anywhere.
Used in human trials: 250 ± 66 MBq, Single injection, Intravenous (Study: dosimetry and scan timing, 8 patients) Details ↓
Recommended Dosing
Used in human trials
No manufacturer dose exists for this use: these are amounts given in published trials, not recommendations.
What is it?
Neuroendocrine tumours, which arise from hormone-producing cells in the gut, pancreas, lungs and elsewhere, usually carry large numbers of somatostatin receptors. Somatostatin receptor PET exploits this: a peptide resembling somatostatin is tagged with a radioactive atom and injected, it collects on receptor-rich tissue, and the scanner shows where. The standard tracers carry gallium-68, which comes from a small on-site generator that yields only a few patient doses at a time. Fluorine-18, made in a cyclotron, lasts longer and can be made in large batches, so groups have looked for a fluorine-18 version.
SiTATE is one answer, first used clinically at LMU Munich. It is Tyr3-octreotate, the same peptide used in gallium-68 dotatate, with a SiFAlin group attached. That group holds a silicon atom bonded to a fluorine atom; mixing it with fluorine-18 swaps the ordinary fluorine for the radioactive one at room temperature. The published synthesis takes about 30 minutes and gives a product of over 97% radiochemical purity with no complicated purification, which the authors describe as close to a kit. Its sibling, AlF-NOTA-octreotide, reaches the same goal with a different chemistry.
The first patient images were published in 2019. In the first 13 patients scanned with both tracers, SiTATE showed somewhat more uptake than gallium-68 DOTATOC in the liver, spleen and adrenals and clearly more in the kidneys, but also higher uptake in metastases in the liver, lymph nodes and bone; five blinded readers rated image quality excellent for both. A dosimetry study in eight patients put the effective dose at 0.015 mSv per MBq, similar to gallium-68 agents, and found the best balance of image quality and contrast at 120 minutes.
Later work checked it against what is under the microscope and against other scans. In 47 patients scanned before surgery, uptake correlated with somatostatin receptor 2 staining in the removed tissue, and the scan found lymph node spread with 74% sensitivity and 100% specificity. In the first prospective comparison, 38 patients had both SiTATE and fluorine-18 DOPA PET: per lesion, SiTATE found 87% against 73%, with each tracer the better one in a few patients. Long-acting somatostatin drugs lowered uptake in liver and spleen but not tumour contrast, so the authors saw no need to pause treatment before a scan. A standard reporting framework, SSTR-RADS, worked reproducibly with it across four readers.
Because healthy brain takes up almost none of it, SiTATE gives very high contrast in meningioma, the common tumour of the brain's coverings. In 107 patients it showed meningiomas far more avidly than other lesions and found a quarter of meningioma sites that earlier imaging had not reported; a second centre found similar contrast in 37 patients with no tracer-related adverse events. It has also been used in phaeochromocytoma and paraganglioma, where it detected disease in 97% of 34 patients and helped select five patients for radioligand therapy, and in thyroid cancer, where in the medullary type the tumour volume on PET tracked blood calcitonin.
Newer long axial field-of-view scanners are far more sensitive, and on one such scanner the injected activity could be cut by two-thirds, from 3.0 to 1.0 MBq per kg, with all lesions still visible. SiTATE remains an investigational tracer prepared in the hospitals that use it. No FDA or EMA record exists and no registered trial was found, and most of the published experience comes from German university hospitals, LMU Munich above all, much of it retrospective.
Mechanism of Action
SiTATE carries fluorine-18 to somatostatin receptors, mainly subtype 2, so receptor-rich tumours light up on a PET scan.
Somatostatin receptor binding
The octreotate peptide binds somatostatin receptor 2; uptake matched receptor staining in surgical tissue.
SiFA labelling
A silicon-bound fluorine is swapped for fluorine-18 in one mild step, so the tracer can be made in batches.
Imaging and clearance
Normal uptake is highest in spleen, kidneys, liver and adrenals and almost absent in brain, which is why meningiomas stand out.
Published Research
These are studies of SiTATE read from their PubMed abstracts: the first clinical series, dosimetry, histology and head-to-head comparisons in neuroendocrine tumours, work in meningioma, phaeochromocytoma, paraganglioma and thyroid cancer, and the published radiosynthesis method. All are observational or diagnostic studies; none is a randomised trial.
First clinical results against gallium-68 DOTATOC
In 13 patients scanned with both tracers, SiTATE gave significantly higher tumour uptake in liver metastases (SUVmax 18.8 against 12.8), lymph nodes and bone, with significantly more kidney uptake. Tumour-to-liver and tumour-to-spleen ratios were similar, and blinded readers rated image quality excellent in most scans with either tracer.
Dosimetry and best scan time
Eight patients given about 250 MBq were scanned five times up to 3 hours. Normal organs plateaued after an hour while tumour uptake kept rising. The effective dose was 0.015 mSv per MBq, comparable to gallium-68 tracers, and 120 minutes, then 60, gave the best trade-off of quality and contrast.
Prospective comparison with 18F-DOPA
38 patients with suspected neuroendocrine tumours had both scans. 22 were negative on both; DOPA was judged more accurate in three and SiTATE in four. Per lesion, SiTATE was more sensitive (86.7% against 73.4% of 143 lesions), with similar tumour-to-background ratios.
Checked against surgical tissue
In 47 patients operated on within four months of the scan, tracer uptake correlated with somatostatin receptor 2 staining (r about 0.62). In 35 who had the primary tumour and lymph nodes removed, the scan detected nodal spread with 73.9% sensitivity and 100% specificity.
No need to pause somatostatin drugs
In 77 patients scanned in routine care, the 40 who had taken a long-acting somatostatin analogue within 28 days showed lower uptake in liver and spleen and higher blood-pool activity, but tumour-to-liver and tumour-to-background ratios did not differ, so the authors found no reason to stop treatment before the scan.
A reporting framework holds up
Four readers scored scans of 95 patients twice using SSTR-RADS 1.0. Agreement on target lesions, overall score and the recommendation for radioligand therapy was excellent, though lymph node scoring agreed less well and experienced and inexperienced readers differed in therapy recommendations.
Lower activity on a long axial scanner
Scans of 24 patients given 3.0 MBq/kg were reprocessed to simulate lower activities. At 1 MBq/kg, a two-thirds reduction, every lesion was still found and uptake values barely changed; at 0.25 MBq/kg detection fell to 70-93% depending on reconstruction mode.
Kidney uptake and kidney function
In 85 patients who went on to lutetium-177 dotatate therapy, kidney uptake on SiTATE or gallium-68 PET moderately tracked each kidney's share of function on renography (r 0.46 for SiTATE) but not overall kidney function, so it could not replace standard kidney tests.
First large meningioma series
107 patients with 117 scans and 231 meningioma lesions: uptake was minimal in healthy brain and far higher in meningiomas than in other lesions (SUVmax 11.6 against 4.0). Two in five meningiomas extended partly into bone, and 25.6% of the lesions found had not been reported on previous standard imaging.
Meningioma at a second centre
Of 37 consecutive patients with known or suspected meningioma, 32 showed uptake consistent with meningioma, 69 lesions in all, with intense tumour uptake (SUVmax about 20) against almost none in normal brain. No tracer-related adverse events occurred.
Phaeochromocytoma and paraganglioma
In 34 patients the patient-level detection rate was 96.6%. Tumour volume and total uptake correlated moderately with chromogranin A and with metanephrine secretion, and hereditary cluster 1 tumours took up more tracer than sporadic ones; in a subgroup, uptake did not differ from gallium-68 DOTATOC.
Choosing and following radioligand therapy
In five patients with metastatic phaeochromocytoma or paraganglioma, high uptake (Krenning score 3-4) supported radioligand therapy; 2.5 months after treatment all had stable disease by CT criteria, but PET tumour volume rose in three, showing the measures can disagree.
Thyroid carcinoma
In a prospective observational study of 21 patients (10 medullary, 11 differentiated thyroid cancer; 37 scans), bone and lymph node metastases took up the most tracer. In medullary cancer total tumour volume on PET correlated with calcitonin (r 0.77); in differentiated cancer it did not track thyroglobulin.
How it is made
A published protocol for clinical-grade production: fluorine-19 on the silicon atom is exchanged for fluorine-18 at room temperature, giving [18F]SiTATE in about 30 minutes with 42% yield, over 97% radiochemical purity and molar activity around 60 GBq/µmol, without complex purification.
Dosing Data
SiTATE has no approved label. These are radioactive activities given in published human studies, each a single injection before a PET scan.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
What a Buyer Needs to Know
What is sold, how it is mixed, stored and taken, and what is known about its safety, quality and legal status. Each part names its source. Where we have none, it says unknown.
What is sold
Unknown: we hold no regulator's label that says in what form SiTATE is supplied. It is a radioactive drug: the next part says where it is prepared and given.
Mixing a vial: a worked example
Nothing to mix at home, and no syringe units to work out: SiTATE is a radioactive drug, prepared and given in nuclear-medicine departments, and its dose is an amount of radioactivity (MBq or GBq), not a weight.
This page's dosing note: “SiTATE is dosed by radioactivity and labelled in a hospital radiopharmacy shortly before the scan; no reconstitution maths applies.”
Source: this page's own note in Dosing Data below; the amount of each dose row in Dosing Data below.
Storage before and after mixing
Unknown: no label on file says how SiTATE is stored. It is a radioactive drug held by the nuclear-medicine department that prepares and gives it (see the part above); the home rules for a mixed vial in the mixing guide do not apply to it.
How it is taken
As it was given in human studies: Intravenous (Single injection; Study: dosimetry and scan timing, 8 patients).
Source: Used in human trials: the route and frequency of each row in Dosing Data below.
What to expect, and when
How long it stays in the body: not established by a measurement cited on this entry.
How long the doses were given: Study: dosimetry and scan timing, 8 patients: Scans 10 to 180 minutes after injection; Study: routine scans on a long axial field-of-view scanner, 24 patients: One PET/CT.
When effects appear: unknown; no source on this page gives a time to effect for SiTATE. Results reported in the studies are under Published Research.
Source: Used in human trials, the duration of each row in Dosing Data below.
Side effects, and when to stop or get help
From the Side Effects section: No tracer-related adverse events in 37 meningioma patients (PMID 42665702); Radiation exposure: an effective dose of 0.015 mSv per MBq (PMID 33928401); High kidney uptake, higher than with gallium-68 DOTATOC (PMID 31492994). Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping SiTATE. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“From the studies above”).
Interactions
Unknown: a PubMed search for human interaction studies of SiTATE (reviewed 2026-10-28) found none. Unknown is not the same as safe to combine.
Every peptide's record, with its source: the interaction matrix.
Checking what you bought
Unknown: no published independent test of SiTATE products is in our lab-results database yet, so how products sold under this name measure up is not known.
To read a certificate of analysis, paste it into the COA decoder. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: In Clinical Trials (Not approved: Drugs@FDA and the EMA medicines list hold no record (searched October 29, 2026), and ClinicalTrials.gov returned no study under SiTATE or SiFAlin-TATE). Sport: Prohibited (S0 catch-all).
Country by country ↓ · Regulatory tracker
Source: this entry's approval status and the WADA Prohibited List, as in Legal Status below.
Side Effects & Contraindications
Reported Side Effects
From the studies above. Only one abstract reported on adverse events, and it found none from the tracer.
Contraindications & Cautions
No approved label exists, so there are no official contraindications. Points from the studies above:
Legal Status
SiTATE is an investigational PET tracer, not approved by FDA or the EMA.
Frequently Asked Questions
?What is SiTATE?
A somatostatin receptor PET tracer: the peptide Tyr3-octreotate with a silicon fluoride acceptor group that holds radioactive fluorine-18. It shows where receptor-rich tumours are.
?How is it different from gallium-68 dotatate?
It uses the same targeting peptide but carries fluorine-18 instead of gallium-68. Fluorine-18 lasts longer and can be made in large batches, which eases logistics; uptake and image quality were comparable or higher in early comparisons.
?Is it approved?
No. FDA and the EMA hold no record of it, and no registered trial was found. It is used at hospitals, mostly in Germany, that make it on site.
?What is it used for?
Mainly neuroendocrine tumours, and also meningiomas, phaeochromocytomas and paragangliomas, and thyroid cancer, all of which can carry somatostatin receptors.
?Do I need to stop somatostatin drugs before the scan?
In one study of 77 patients, long-acting somatostatin drugs lowered uptake in liver and spleen but not tumour contrast, so the authors saw no need to pause them. Your nuclear medicine team decides.
References
- [other] European Medicines Agency, medicines list, and Drugs@FDA (openFDA): no record for SiTATE or SiFAlin-TATE; ClinicalTrials.gov API v2: no study under either name (all searched October 29, 2026).
- [pubmed] Ilhan H, et al. "Biodistribution and first clinical results of (18)F-SiFAlin-TATE PET: a novel (18)F-labeled somatostatin analog for imaging of neuroendocrine tumors." Eur J Nucl Med Mol Imaging, 2020;47(4):870-880. PMID: 31492994.
- [pubmed] Beyer L, et al. "Dosimetry and optimal scan time of [(18)F]SiTATE-PET/CT in patients with neuroendocrine tumours." Eur J Nucl Med Mol Imaging, 2021;48(11):3571-3581. PMID: 33928401.
- [pubmed] Roll W, et al. "Head to head comparison of [(18)F]SiTATE versus [(18)F]DOPA-PET in patients with neuroendocrine tumors." Eur J Nucl Med Mol Imaging, 2026;53(3):1803-1810. PMID: 41003763.
- [pubmed] Trautwein NF, et al. "Histologic Ex Vivo Validation of the [(18)F]SITATE Somatostatin Receptor PET Tracer." J Nucl Med, 2025;66(8):1204-1209. PMID: 40404394.
- [pubmed] Eschbach RS, et al. "Comparison of somatostatin receptor expression in patients with neuroendocrine tumours with and without somatostatin analogue treatment imaged with [(18)F]SiTATE." Front Oncol, 2023;13:992316. PMID: 36793617.
- [pubmed] Ebner R, et al. "Validation of the standardization framework SSTR-RADS 1.0 for neuroendocrine tumors using the novel SSTR‑targeting peptide [(18)F]SiTATE." Eur Radiol, 2024;34(11):7222-7232. PMID: 38769164.
- [pubmed] Trautwein NF, et al. "Low-activity [(18)F]-somatostatin receptor (SSTR) imaging using [(18)F]SiTATE on a long axial field-of-view PET/CT scanner." EJNMMI Phys, 2025;12(1):13. PMID: 39907960.
- [pubmed] Tiling M, et al. "Estimation of split renal function on PET using the SSTR-targeting radioligands [(18)F]SiTATE, [(68)Ga]Ga-DOTA-TATE and [(68)Ga]Ga-DOTA-TOC in a theranostic setting." Eur J Nucl Med Mol Imaging, 2026;53(9):5491-5500. PMID: 42141279.
- [pubmed] Unterrainer M, et al. "Next-generation PET/CT imaging in meningioma-first clinical experiences using the novel SSTR-targeting peptide [(18)F]SiTATE." Eur J Nucl Med Mol Imaging, 2023;50(11):3390-3399. PMID: 37358620.
- [pubmed] Sachpekidis C, et al. "High-contrast somatostatin receptor imaging of meningiomas with [¹⁸F]SiTATE PET/CT." Eur J Nucl Med Mol Imaging, 2026. PMID: 42665702.
- [pubmed] Onkes M, et al. "[(18)F]SiTATE-PET/CT for detection of pheochromocytomas and paragangliomas: comparison of biochemical secretion, genotype and imaging metrics." Eur J Nucl Med Mol Imaging, 2025;52(13):5175-5188. PMID: 40445313.
- [pubmed] Siegmund SC, et al. "[(18)F]SiTATE PET for PRRT selection and monitoring metastatic tumors of the adrenal medulla and extra-adrenal paraganglia." Eur J Nucl Med Mol Imaging, 2026;53(3):1671-1678. PMID: 40970962.
- [pubmed] Kunte SC, et al. "PET/CT imaging of differentiated and medullary thyroid carcinoma using the novel SSTR-targeting peptide [(18)F]SiTATE - first clinical experiences." Eur J Nucl Med Mol Imaging, 2025;52(3):900-912. PMID: 39404789.
- [pubmed] Lindner S, et al. "Radiosynthesis of [(18)F]SiFAlin-TATE for clinical neuroendocrine tumor positron emission tomography." Nat Protoc, 2020;15(12):3827-3843. PMID: 33230332.
- [pubmed] Ilhan H, et al. "First-in-human (18)F-SiFAlin-TATE PET/CT for NET imaging and theranostics." Eur J Nucl Med Mol Imaging, 2019;46(11):2400-2401. PMID: 31352578.
- [pubmed] Calderón E, et al. "One-day dual-tracer examination in neuroendocrine neoplasms: a real advantage of low activity LAFOV PET imaging." Eur J Nucl Med Mol Imaging, 2025;52(7):2463-2476. PMID: 39883139.
Sources & Citations
Every study on this page was read from its PubMed record on October 29, 2026. Regulatory and registry status comes from Drugs@FDA (openFDA), the EMA medicines list and ClinicalTrials.gov, searched the same day. Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.