Technetium Tc 99m Apcitide
The first approved scan to look for clots that are still forming, by tagging activated platelets
Apcitide is a small synthetic peptide that sticks to activated platelets, the cells that pile up in a clot while it is forming. Labelled with technetium-99m, it was approved in the US in 1998 as AcuTect to image acute deep vein thrombosis in the legs with an ordinary gamma camera. The product is now discontinued.
Last FDA label of a product discontinued in the US (not a current US recommendation): About 100 µg bibapcitide labelled with 20 mCi technetium-99m, Single injection into an arm vein, Intravenous Details ↓
Recommended Dosing
Last FDA label of a product discontinued in the US (not a current US recommendation)
From the last US prescribing information of a product discontinued in the US (see the regulatory status on this page). It records what that label said while the product was sold there; it is not a current US recommendation. Other doses studied, if any, are in the full dosing data below.
Used in human trials
No manufacturer dose exists for this use: these are amounts given in published trials, not recommendations.
What is it?
A deep vein thrombosis (DVT) is a clot in a deep vein, usually in the leg. It matters because a piece can break off and lodge in the lungs. Most tests for it look at the shape of the vein: contrast venography fills the vein with dye and shows a gap where the clot sits, and ultrasound checks whether the vein squashes flat under the probe. Neither says whether a clot is new or months old, which is a real problem in someone who has had a DVT before and comes back with a swollen leg.
Apcitide was built to answer that question. Platelets switch on when a clot is forming and display a receptor called glycoprotein IIb/IIIa, the same receptor that the drug eptifibatide blocks. Apcitide binds that receptor. Carrying technetium-99m, it gathers in clots that are still active, and a gamma camera picks them up. In the first patient studies in 1995, under its early code P280, it showed clots within an hour in most people with recent symptoms and was negative in patients whose clots were more than about six weeks old.
The phase 3 programme ran two trials in North America and Europe with 280 patients. Read blind, apcitide agreed with blind-read venography about 69% of the time, with a sensitivity of 73% and specificity of 68%, which met the trials' targets. In the 63 patients with no previous clot who came in within three days of symptoms, the agreement rose to about 87%. A smaller study found that reading the 10, 60 and 120-minute images together worked better than any single time point. FDA approved the AcuTect kit in September 1998.
The label was careful about what the scan could not do. No follow-up study had checked what happened to people whose scan was negative, so the label said a negative scan alone should not be the reason to withhold anticoagulants. It also noted that the peptide inhibits platelet clumping at concentrations above those given, and that its effect on bleeding time had not been studied.
Later studies found the scan useful but limited. A 2008 Austrian study detected 14 of 16 leg clots, some up to 17 days old, but found only one of six proven pulmonary emboli: the lungs and heart hold too much blood for small emboli to stand out on planar images. Case reports described incidental findings, such as uptake in the brain of a stroke patient and a hot spot in the liver that led to a diagnosis of superior vena cava obstruction. Animal work found clots in the heart of pigs with atrial fibrillation.
AcuTect is now listed as discontinued in Drugs@FDA, and no current US label exists on DailyMed. Reviews from 2003 and 2004 describe it as the only radiolabelled peptide approved in the US for imaging venous clots, and its interest now is mostly as a proof that a small peptide can image a biological process, clot activity, rather than the shape of a vein.
Mechanism of Action
Apcitide is a synthetic peptide that binds the glycoprotein IIb/IIIa receptor, which platelets display when they are activated in a forming clot; its technetium-99m label makes the clot visible to a gamma camera.
Activated platelets
Its ring carries an arginine-glycine-aspartate motif, with an arginine mimic, that fits the GP IIb/IIIa receptor; resting platelets bind it far less.
New clots, not old
Binding needs platelet activation, so clots older than about six weeks showed little uptake in early studies.
Gamma-camera imaging
Technetium-99m allows planar imaging of both legs 10 to 60 minutes after injection; the label permits repeat images up to 180 minutes.
Kidney clearance
Half the activity reached the urine by 2 hours and about 80% within a day; the bladder wall received the highest radiation dose.
Published Research
Studies whose titles name apcitide or its early code P280, read from their PubMed abstracts on October 29, 2026, with the 1998 AcuTect label. Three papers titled for the class rather than the molecule are listed under References.
Phase 3 trials against venography
Two trials in North America and Europe enrolled 280 people within 10 days of DVT symptoms or high-risk surgery; 243 could be evaluated and about 62% were on heparin. Blind reads gave 73.4% sensitivity, 67.5% specificity and 69.1% agreement with blind-read venography, meeting the target in both trials. In 63 patients with no earlier clot who came within 3 days of symptoms, the figures were 90.6%, 83.9% and 87.3%.
Early against delayed images
In 39 people with suspected acute DVT given about 740 MBq, sensitivity against venography was 64% at 10 minutes, 68% at 60 minutes and 76% at 120 minutes, and 86% when all three sets were read together; specificity ranged from 76% to 88%. Combining at least two time points gave the best accuracy.
Clots in the legs and lungs
Nineteen patients received a mean of 841 MBq within a day of admission. The scan showed fresh clot in 14 of 16 patients whose ultrasound or venography showed DVT, including clots up to 17 days old, and was negative in all three without DVT, but it showed only one of six proven pulmonary emboli.
First patient study (as P280)
Nine people with confirmed DVT were imaged after 10 to 22 mCi. Clots showed within an hour in eight; the one negative scan was in a clot diagnosed 42 days earlier. Uptake was also seen in two pulmonary emboli and, unexpectedly, a cerebellar haemangioblastoma. No adverse effects were noted.
Fresh clots versus old ones (as P280)
In 15 Italian patients with DVT or pulmonary embolism given about 200 µg of peptide with 10 to 23 mCi, under 5% of the dose stayed in the blood at one hour. Clots showed in 11 of 15; all four negative scans were in people whose clots had begun more than 40 days earlier, consistent with binding only where clotting is active. Tomographic images found two clots that planar views missed.
Case: stroke seen on a leg scan
A patient with stroke and a swollen leg was sent for an apcitide scan to look for DVT. The legs were clear, but the tracer gathered in the left parieto-occipital brain, matching the acute stroke found on CT and clinical examination.
Case: liver hot spot
A focal spot of activity in the liver on a technetium-99m blood pool scan and an apcitide scan led to the diagnosis of superior vena cava obstruction; the authors explain the collateral veins that carry blood, and tracer, to that part of the liver.
Guide for technologists
A training article for nuclear medicine technologists covering patient preparation, the activity given, positioning and gamma-camera settings for apcitide imaging of acute DVT, with clinical cases showing the whole-body distribution.
How technetium binds the peptide
Chemistry study of the 13-amino-acid apcitide and its dimer bibapcitide, the form in the AcuTect kit. Mass spectrometry and NMR showed the technetium-oxo core binds the Gly-Gly-Cys segment at the peptide's end, leaving the receptor-binding ring free.
Atrial clots in pigs
In five pigs with induced atrial fibrillation and implanted clot material in the left atrium, apcitide imaging detected the atrial clot in every animal, confirmed at post-mortem.
Dosing Data
The first row is the 1998 AcuTect label, the last US label of a discontinued product. It records what the label said; it is not a current recommendation. The second row is what a published study gave. Both describe one injection of a radioactive tracer prepared and given in nuclear-medicine departments.
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 Technetium Tc 99m Apcitide 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: Technetium Tc 99m Apcitide 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: “Apcitide was measured in radioactivity and prepared from the AcuTect kit in nuclear-medicine departments, and the product is discontinued.”
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 Technetium Tc 99m Apcitide 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 the approved label gives it: Intravenous (Single injection into an arm vein; Last US label (AcuTect, discontinued): acute venous thrombosis of the legs).
Source: Last FDA label of a product discontinued in the US (not a current US recommendation): the route and frequency of each row in Dosing Data below.
What to expect, and when
How long it stays in the body: a half-life of about 2 hours for total blood radioactivity in 20 people (18 at risk of thrombosis, 2 volunteers); 2.5 hours in 10 healthy volunteers. After about five half-lives almost none is left.
How long the doses were given: Last US label (AcuTect, discontinued): acute venous thrombosis of the legs: Image 10 to 60 minutes after injection; further images up to 180 minutes without reinjection.
When effects appear: unknown; no source on this page gives a time to effect for Technetium Tc 99m Apcitide. Results reported in the studies are under Published Research.
Source: half-life: AcuTect US prescribing information (September 1998 approval labeling on Drugs@FDA, NDA 020887), Clinical Pharmacology; Last FDA label of a product discontinued in the US (not a current US recommendation), the duration of each row in Dosing Data below.
Side effects, and when to stop or get help
From the Side Effects section: At least one adverse event in 29 of 642 patients (4.5%); pain in the back, leg or chest was the most common (1.7%); Headache (0.8%), low blood pressure (0.8%) and high blood pressure (0.5%); One serious episode of low blood pressure, starting within 10 minutes of injection and falling to a systolic pressure of 70 mmHg; Rare moderate rises in liver enzymes; no adverse effects in the first nine-patient study. Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping Technetium Tc 99m Apcitide. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“From the AcuTect label, which pooled 642 adults in its clinical studies, and the studies above”).
Interactions
Unknown: a PubMed search for human interaction studies of Technetium Tc 99m Apcitide (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 Technetium Tc 99m Apcitide 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; it checks the measured mass against Technetium Tc 99m Apcitide's expected mass, 1,392.6 Da, from this entry's molecular data. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: Discontinued (FDA-approved as AcuTect (kit for the preparation of technetium Tc 99m apcitide), NDA 020887, on September 14, 1998, for scintigraphic imaging of acute venous thrombosis in the legs). Sport: Not on the 2026 List.
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 AcuTect label, which pooled 642 adults in its clinical studies, and the studies above.
Contraindications & Cautions
The label listed no contraindications. Its warnings and precautions:
Legal Status
Approved in the US in 1998 and since discontinued; never authorised by the EMA.
Frequently Asked Questions
?What was apcitide used for?
Labelled with technetium-99m and sold as the AcuTect kit, it was used to scan the legs for acute deep vein thrombosis in people with symptoms.
?Is AcuTect still available?
No. Drugs@FDA lists it as discontinued, and DailyMed carries no current label.
?How accurate was it?
In the phase 3 trials it agreed with venography in about 69% of blind readings, and about 87% in people with a first clot and recent symptoms.
?Why could it tell new clots from old ones?
It binds a receptor that platelets show only when they are activated, which happens while a clot is forming. Patients whose clots were more than about six weeks old had negative scans in early studies.
?Could it find clots in the lungs?
Poorly. A 2008 study found only one of six proven pulmonary emboli, because the heart and lungs hold so much blood that small emboli do not stand out on planar images.
?How is it related to eptifibatide?
Both act on the platelet glycoprotein IIb/IIIa receptor. Eptifibatide is given in large amounts to block it during heart procedures; apcitide was given in microgram amounts with a radioactive label to show where it sits.
?Was it safe?
In 642 adults in the label's studies, 4.5% had any adverse event, mostly pain, headache or changes in blood pressure; one person had a serious drop in blood pressure.
References
- [other] PubChem CID 9812576, Apcitide: formula C51H77N17O19S5, molecular weight 1392.6. Read October 28, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/9812576
- [other] US FDA, Drugs@FDA (openFDA): ACUTECT, NDA 020887, original approval September 14, 1998; marketing status discontinued. Read October 28, 2026.
- [fda] AcuTect (Kit for the Preparation of Technetium Tc 99m Apcitide Injection) prescribing information, September 14, 1998 approval labeling (Diatide), Drugs@FDA NDA 020887, label 20887lbl.pdf. Read October 29, 2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/1998/20887lbl.pdf
- [clinical-trial] Taillefer R, et al. "Acute thromboscintigraphy with (99m)Tc-apcitide: results of the phase 3 multicenter clinical trial comparing 99mTc-apcitide scintigraphy with contrast venography for imaging acute DVT. Multicenter Trial Investigators." J Nucl Med, 2000;41(7):1214-23. PMID: 10914912.
- [pubmed] Taillefer R, et al. "Comparison of early and delayed scintigraphy with 99mTc-apcitide and correlation with contrast-enhanced venography in detection of acute deep vein thrombosis." J Nucl Med, 1999;40(12):2029-35. PMID: 10616882.
- [pubmed] Dunzinger A, et al. "99mTc-apcitide scintigraphy in patients with clinically suspected deep venous thrombosis and pulmonary embolism." Eur J Nucl Med Mol Imaging, 2008;35(11):2082-7. PMID: 18618107.
- [pubmed] Muto P, et al. "Detecting deep venous thrombosis with technetium-99m-labeled synthetic peptide P280." J Nucl Med, 1995;36(8):1384-91. PMID: 7629582.
- [pubmed] Lastoria S, et al. "[Imaging of thromboembolism by scintigraphy with the 99m-technetium-labelled synthetic peptide P280]." Radiol Med, 1995;90(6):812-9. PMID: 8685469.
- [pubmed] Tepmongkol S. "Detection of acute cerebral ischaemia with Tc-99m apcitide scintigraphy." Neuroradiology, 2002;44(10):819-21. PMID: 12389129.
- [pubmed] Sherman PM, et al. "Focal accumulation of a radiopharmaceutical in the liver on technetium-99m gated blood pool and Apcitide scintigraphy leading to the diagnosis of superior vena cava obstruction." Mil Med, 2002;167(1):79-82. PMID: 11799821.
- [review] Carretta RF, et al. "Optimizing images of acute deep-vein thrombosis using technetium-99m-apcitide." J Nucl Med Technol, 1999;27(4):271-5. PMID: 10646544.
- [pubmed] Francesconi LC, et al. "Preparation and characterization of [99TcO] apcitide: a technetium labeled peptide." Inorg Chem, 2004;43(9):2867-75. PMID: 15106974.
- [pubmed] DeHoyos MJ, et al. "Detection of acute atrial thrombus in a porcine model with atrial fibrillation with tc 99m-apcitide." Invest Radiol, 2004;39(4):197-201. PMID: 15021322.
- [pubmed] Bates SM, et al. "Imaging characteristics of a novel technetium Tc 99m-labeled platelet glycoprotein IIb/IIIa receptor antagonist in patients With acute deep vein thrombosis or a history of deep vein thrombosis." Arch Intern Med, 2003;163(4):452-6. PMID: 12588204.
- [pubmed] Taillefer R. "Radiolabeled peptides in the detection of deep venous thrombosis." Semin Nucl Med, 2001;31(2):102-23. PMID: 11330782.
- [pubmed] Bernarducci MP. "'Pathophysiologic mapping' of venous thromboembolism: opportunities for radiolabeled peptides." Q J Nucl Med, 2003;47(4):292-320. PMID: 14973421.
Sources & Citations
Studies were read from their PubMed abstracts on October 29, 2026. The dose, side-effect, warning and half-life details come from the September 1998 AcuTect approval labeling, the last label on Drugs@FDA (DailyMed has none), read 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.