TechneScan MAG3: Uses, Dosage & Side Effects
A diagnostic radiopharmaceutical kit used to prepare technetium (99mTc) mertiatide injection for dynamic renal scintigraphy, including assessment of kidney function, obstructive uropathy, renal transplants and renovascular hypertension
TechneScan MAG3 is a kit used in nuclear medicine departments to prepare an injectable solution of technetium-99m mertiatide (99mTc-MAG3), a radiopharmaceutical that is rapidly and almost exclusively extracted by the kidneys. Once injected into a vein, it produces images of the kidneys and urinary tract on a gamma camera, allowing doctors to measure how well each kidney filters and drains urine. TechneScan MAG3 is used to evaluate split (differential) renal function, to investigate suspected obstruction of the urinary tract, to monitor renal transplants, to screen for renovascular hypertension when combined with an ACE inhibitor, and to assess kidney function in patients with reduced glomerular filtration. It is a prescription-only medicine, always administered in a hospital or specialised clinic by qualified nuclear medicine staff, and the amount of active substance injected is measured in micrograms so pharmacological side effects are extremely rare.
Quick Facts: TechneScan MAG3
Key Takeaways
- TechneScan MAG3 is a cold kit used to radiolabel betiatide (MAG3) with technetium-99m, creating a short-lived radiopharmaceutical that is almost entirely excreted by the kidneys and is ideal for imaging renal function, even in patients with impaired filtration.
- It is the tracer of choice for dynamic renal scintigraphy because it is cleared primarily by active tubular secretion, providing high target-to-background contrast and allowing reliable measurement of split kidney function, drainage and transit times.
- Clinical applications include assessment of obstructive uropathy (diuretic renogram with furosemide), renovascular hypertension (captopril renogram), renal transplant evaluation, pediatric hydronephrosis, and follow-up of patients with chronic kidney disease.
- The typical adult administered activity is 40-200 MBq, giving an effective dose of approximately 0.3-1.4 mSv - a diagnostic radiation exposure comparable to a few months of natural background radiation and lower than many CT examinations.
- Pharmacological side effects are extremely rare because the injected chemical mass is only a few micrograms; the main safety considerations are radiation protection (especially in pregnancy and breastfeeding) and very rare hypersensitivity reactions.
What Is TechneScan MAG3 and What Is It Used For?
TechneScan MAG3 is not a therapeutic drug in the conventional sense - it is a diagnostic radiopharmaceutical, designed solely to allow doctors to see how the kidneys are working. The product is supplied to nuclear medicine departments as a sterile, freeze-dried (lyophilised) powder contained in a glass vial, together with ancillary agents that are required for the labelling reaction. On the day of the examination, the powder is mixed under aseptic conditions with sodium pertechnetate (99mTc) injection obtained from a technetium generator. The resulting complex is technetium-99m mercaptoacetyltriglycine - better known as 99mTc-MAG3 - which is then drawn up into a syringe and injected into the patient.
The chemical backbone of the tracer is mertiatide (international non-proprietary name), a small triglycine-based molecule that carries a sulphur donor atom capable of binding tightly to the technetium-99m ion. Once formed, the 99mTc-MAG3 complex has the remarkable property of being almost completely extracted from the bloodstream by the kidneys in a single pass, predominantly by active secretion in the proximal tubule via the organic anion transporter system (OAT1/OAT3). A much smaller fraction (less than 5%) passes into the urine by glomerular filtration. This pharmacokinetic profile is what makes 99mTc-MAG3 the preferred tracer for functional renal imaging in most modern nuclear medicine practice.
Technetium-99m is the most widely used medical radionuclide in the world. It emits gamma rays of 140 keV, an energy that is almost ideal for imaging with a modern gamma camera, and its short physical half-life of 6 hours means that radiation exposure drops rapidly after the scan is complete. Biological clearance of 99mTc-MAG3 through the urinary tract further shortens the effective half-life in the body, so that by 24 hours after injection the residual radioactivity is negligible.
TechneScan MAG3 is authorised for use in adult and paediatric patients for the following indications:
- Evaluation of renal function and split function - quantifying the percentage contribution of each kidney to overall renal function, which is essential for planning nephrectomy, partial nephrectomy, donor work-up and treatment of congenital urological abnormalities.
- Assessment of obstructive uropathy - often combined with a diuretic challenge (furosemide), the so-called diuretic renogram, to differentiate mechanical obstruction from non-obstructive dilatation of the renal pelvis or ureter.
- Screening for renovascular hypertension - by comparing renograms performed with and without an ACE inhibitor (usually oral captopril), the captopril-enhanced renogram can identify haemodynamically significant renal artery stenosis.
- Evaluation of renal transplants - 99mTc-MAG3 is used immediately after transplantation and during long-term follow-up to detect acute tubular necrosis, urinary leak, ureteral obstruction, rejection and vascular complications.
- Assessment of renal function in impaired kidneys - because extraction is dominated by tubular secretion rather than filtration, 99mTc-MAG3 continues to give high-quality images even when the glomerular filtration rate (GFR) is severely reduced, making it the tracer of choice in chronic kidney disease and in elderly patients.
- Investigation of paediatric uropathies - including antenatally detected hydronephrosis, vesico-ureteric reflux, the poorly functioning kidney, and congenital anomalies such as duplex systems and horseshoe kidney.
Compared with older renal tracers, 99mTc-MAG3 represents a major advance. The previous gold standard, 131I-orthoiodohippurate (131I-OIH), had unfavourable imaging characteristics and delivered a relatively high radiation dose because of iodine-131's beta emissions. 99mTc-DTPA, another Tc-99m labelled tracer, relies on glomerular filtration and performs poorly when GFR is low. 99mTc-MAG3 combines the excellent imaging properties of technetium-99m with kidney-specific tubular extraction, so it produces clear, high-contrast images with low radiation dose across a wide range of renal function.
Dynamic acquisition begins the moment the tracer is injected. A gamma camera positioned over the patient's back (or, for a transplant, over the abdomen) records a sequence of images - typically one image every 10-20 seconds for 20-30 minutes. The resulting data are reconstructed into time-activity curves for each kidney, showing the vascular phase (tracer arriving in the renal arteries), the cortical phase (tracer accumulating in the kidney parenchyma) and the excretory phase (tracer draining into the renal pelvis, ureters and bladder). From these curves, the nuclear medicine physician can calculate the split function, the time to peak uptake, the time to half-maximum clearance and, if required, quantitative measures such as effective renal plasma flow.
What Should You Know Before Receiving TechneScan MAG3?
Contraindications
There are very few absolute contraindications to TechneScan MAG3, reflecting the excellent safety profile of this and other technetium-99m agents. However, the following situations should be considered carefully before administration:
- Hypersensitivity: TechneScan MAG3 should not be administered to patients with known hypersensitivity to the active substance (betiatide / mertiatide) or to any of the excipients, including sodium pertechnetate (99mTc). A documented previous anaphylactic reaction to a Tc-99m-labelled agent is a contraindication.
- Pregnancy: When in doubt, exposure to ionising radiation during pregnancy should be avoided. Pregnancy should be excluded in women of childbearing potential before administration; if the scan cannot be postponed, the benefits must clearly outweigh the risks to the fetus, and the lowest possible activity should be used.
Warnings and Precautions
Like all radiopharmaceuticals, TechneScan MAG3 exposes the patient to a small dose of ionising radiation. The administered activity must be justified in terms of expected diagnostic benefit, and the as low as reasonably achievable (ALARA) principle must be applied. Pregnancy must be excluded in women of reproductive age before administration, and alternative non-ionising imaging (such as ultrasound or MRI) should always be considered first, particularly in children and young adults.
Before and during the examination, inform the nuclear medicine team if any of the following applies to you:
- Hydration status: Patients are normally asked to drink approximately 500 mL of water 30-60 minutes before the scan. Good hydration increases urine flow, improves image quality, lowers the radiation dose to the bladder wall and reduces the risk of false-positive obstructive patterns.
- Kidney function: Severe renal impairment does not prevent the scan but may prolong imaging time and change the interpretation of the curves. The nuclear medicine physician will tailor the protocol and analysis accordingly.
- Dehydration: Significant dehydration can produce a falsely abnormal excretory pattern. Dehydration should be corrected before the scan whenever possible, particularly in elderly patients and infants.
- Renal transplant: Special acquisition protocols and regions of interest are used for transplanted kidneys. Recent surgery, stenting or urinary catheters should be mentioned to the team.
- Previous adverse reactions: If you have experienced a reaction to a prior nuclear medicine study or to iodinated contrast media, inform the team in advance so that precautions can be taken.
- Venous access: The tracer must be injected as a rapid bolus; poor venous access or extravasation at the injection site can distort the vascular phase and compromise quantitative analysis.
- Incontinence: Urinary incontinence or indwelling catheters should be identified in advance, both for patient comfort and because contaminated clothing or bedding will retain radioactivity for some hours after the scan.
- Infants and young children: Lower administered activities scaled to body weight are used in paediatric practice (following EANM paediatric dosage card recommendations), and sedation may occasionally be required to ensure the child lies still.
- Diuretic renogram: If a diuretic challenge is planned, inform the team of any allergy to furosemide or sulphonamides. Regular diuretic therapy may need to be withheld for 24 hours before the scan so that the provoked response can be interpreted reliably.
- Captopril renogram: ACE inhibitors and angiotensin receptor blockers are usually stopped 48-72 hours before a captopril-enhanced study, and diuretics are often temporarily paused to avoid false-positive results due to volume depletion. Your referring physician will give specific instructions.
Pregnancy and Breastfeeding
Pregnancy: When nuclear medicine investigations are requested for a woman of childbearing age, the possibility of pregnancy must be actively excluded, for example by a menstrual history and, where appropriate, a pregnancy test. If pregnancy is confirmed, TechneScan MAG3 should be used only if the expected diagnostic information cannot be obtained by non-ionising alternatives (ultrasound, non-contrast MRI) and the benefit clearly outweighs the potential risk to the fetus. The absorbed dose to the uterus from a typical 100 MBq renal scan is estimated at around 0.5 mGy - well below thresholds for deterministic effects, but not negligible in terms of the small stochastic risk.
Breastfeeding: Small amounts of 99mTc activity may appear in human breast milk. According to International Commission on Radiological Protection (ICRP) and EANM recommendations, breastfeeding should be interrupted for at least 4 hours after administration of 99mTc-MAG3, with milk expressed during this period discarded. Close contact with infants should also be limited for several hours after the scan, depending on local radiation protection advice. Milk produced after the interruption period is safe for the infant.
Fertility: No effects on fertility from diagnostic doses of 99mTc-MAG3 have been described. Men and women do not need to avoid conception after the scan, provided pregnancy is not already established at the time of the examination.
Driving and Using Machinery
TechneScan MAG3 has no known influence on the ability to drive or to operate machinery. Patients may leave the department immediately after the scan. However, patients who have received a diuretic during a diuretic renogram may need access to a toilet for several hours and should plan accordingly.
Important Information About Excipients
Each vial of TechneScan MAG3 contains a small amount of sodium after reconstitution. This is usually below the 1 mmol (23 mg) threshold that would require a labelling statement, but patients on a strictly controlled sodium diet should mention it to the nuclear medicine team. The kit also contains stannous chloride (used as a reducing agent for the technetium labelling reaction) in amounts far below any clinically relevant level. The final injection is buffered to a near-physiological pH and contains no preservatives.
How Does TechneScan MAG3 Interact with Other Drugs?
Because the mass of betiatide administered in a typical adult scan is only about 1 mg, and the mass of 99mTc is in the nanogram range, there are effectively no classical pharmacodynamic or pharmacokinetic drug-drug interactions of the kind seen with therapeutic medicines. Instead, the relevant interactions are functional - drugs that change the way the kidney handles the tracer and therefore alter the images and the time-activity curves. The nuclear medicine physician must take these into account to avoid false-positive or false-negative results.
Major Interactions
| Interacting Drug | Effect | Clinical Significance |
|---|---|---|
| ACE inhibitors (captopril, enalapril) and angiotensin receptor blockers | Reduce glomerular filtration in a kidney with renal artery stenosis, accentuating asymmetry on the renogram | Deliberately used in the captopril renogram to detect renovascular hypertension; usually withheld 48-72 hours before a baseline scan to avoid false positives |
| Loop diuretics (furosemide, torsemide) | Induce a brisk rise in urine flow that should wash tracer out of a non-obstructed collecting system | Administered intentionally as the F+20 or F+0 diuretic renogram to differentiate true obstruction from functionally significant dilatation |
| Nephrotoxic agents (aminoglycosides, ciclosporin, tacrolimus, cisplatin, NSAIDs) | Reduce tubular secretion and/or glomerular filtration, impairing tracer extraction | May cause a falsely reduced split function or prolonged transit; correlate with recent drug history and serum creatinine |
| Probenecid and other tubular secretion inhibitors | Competitively inhibit the organic anion transporters that secrete 99mTc-MAG3 | Reduce peak kidney activity and alter the cortical transit; note the medication and interpret with caution |
Minor and Functional Interactions
| Interacting Drug | Effect | Clinical Significance |
|---|---|---|
| Iodinated contrast media (recent administration) | Can transiently impair renal function and alter tracer kinetics | Ideally, scan should be delayed 24-48 hours after a large IV contrast load |
| Beta-blockers and calcium channel blockers | May blunt the renal haemodynamic response during a captopril renogram | Usually continued, but interpretation must take the therapy into account |
| Potassium-sparing diuretics, thiazides | Can alter salt and water balance and influence tracer washout | Document in the medication list; they rarely need to be stopped |
| Lithium | May cause nephrogenic diabetes insipidus with impaired concentrating ability | Does not contraindicate the scan but may influence interpretation of excretory patterns |
| Recent radiopharmaceuticals (e.g., 18F-FDG PET, bone scan) | Residual activity from prior agents can interfere with image quality | Spacing of at least 24 hours from other Tc-99m studies is usually sufficient |
As a general rule, patients should bring a complete, up-to-date list of all prescription medications, over-the-counter drugs, herbal remedies and supplements to their appointment. The nuclear medicine physician will decide, in consultation with the referring doctor, whether any medication needs to be withheld before the study. Patients should never stop a prescribed medication on their own in advance of a renogram; this could be dangerous, particularly for antihypertensives and heart failure drugs.
What Is the Correct Dosage of TechneScan MAG3?
TechneScan MAG3 is prepared in the hospital radiopharmacy by adding sodium pertechnetate (99mTc) injection to the vial, mixing carefully, and waiting approximately 10-15 minutes for the labelling reaction to complete. Quality control (radiochemical purity) is checked before use; the radiochemical purity must be at least 94% according to European Pharmacopoeia requirements. The patient-specific syringe is then dispensed for immediate use - 99mTc-MAG3 is not stored for long periods because its radioactivity decays rapidly.
Adults
Standard Adult Dose - Dynamic Renal Scintigraphy
Indication: Split renal function, obstruction, renal transplant evaluation
Activity: 40-200 MBq intravenously (1-5 mCi), typically around 100 MBq
Administration: Single rapid intravenous bolus through a free-flowing cannula (ideally 20G or larger)
Imaging: Dynamic acquisition begins at the moment of injection and continues for approximately 20-30 minutes
Quantitative Effective Renal Plasma Flow (ERPF)
Indication: Research or advanced clinical assessment of renal function
Activity: Up to 370 MBq intravenously (10 mCi)
Additional procedure: Blood samples may be taken at defined times after injection for plasma clearance calculation
Captopril-Enhanced Renogram
Indication: Screening for renovascular hypertension
Activity: 100-200 MBq intravenously, usually as part of a two-day or one-day protocol
Captopril dose: 25-50 mg oral captopril, given 60 minutes before tracer injection, with blood pressure monitoring
Diuretic (Furosemide) Renogram
Indication: Differentiation of mechanical obstruction from non-obstructive dilatation
Activity: 40-200 MBq intravenously
Furosemide dose: 0.5-1.0 mg/kg IV (maximum 40 mg) given at 20 minutes after tracer (F+20) or simultaneously (F+0), according to local protocol
Children
In the paediatric population, the administered activity is scaled to body weight using the EANM Paediatric Dosage Card. The baseline activity for 99mTc-MAG3 is 11.9 MBq, multiplied by a weight-related factor. A minimum activity of approximately 15 MBq is applied to ensure acceptable image quality in very small infants.
- Neonates and infants (under 1 year): Typically 15-20 MBq, with careful attention to hydration and bladder catheterisation when appropriate.
- Children 1-5 years: Activity scaled by weight, usually in the range 20-50 MBq.
- Children 5-12 years: Typical activity 40-80 MBq.
- Adolescents: Approach adult dosing, usually 80-150 MBq.
For paediatric diuretic renography, furosemide is typically dosed at 1 mg/kg (maximum 40 mg) for infants and at 0.5 mg/kg (maximum 20 mg) for older children, given at F+0, F+20 or F-15 according to local protocol. Paediatric studies should be performed in centres with experience, with both a nuclear medicine physician and a paediatric radiologist available to interpret the images.
Elderly Patients
No specific dose adjustment is needed in elderly patients. Because renal function often declines with age, 99mTc-MAG3 is particularly useful in this population; it continues to provide interpretable images even when GFR is reduced, whereas filtration-dependent tracers such as 99mTc-DTPA may produce poor-quality scans. Hydration status and mobility should be assessed before the scan, and standing transfers from the examination table should be supervised after diuretic renography because of the risk of postural hypotension.
Patients with Renal Impairment
TechneScan MAG3 does not need to be dose-reduced in renal impairment, and is in fact the tracer of choice in this situation. However, acquisition times are often extended, allowing the slow but ongoing extraction to be captured, and the interpretation must be adapted. In anuric patients (for example, dialysis-dependent renal failure) the scan is rarely informative and should be discussed with the referring nephrologist before being booked.
Patients with Hepatic Impairment
Hepatobiliary excretion accounts for less than 3% of 99mTc-MAG3 clearance in normal kidneys, but can become more prominent in severe renal failure. Mild to moderate hepatic impairment does not require dose adjustment. In severe hepatic disease, there may be slightly increased bowel visualisation on delayed images; this does not affect the primary renal analysis.
Missed Dose and Overdose
Because TechneScan MAG3 is given as a single dose at the time of the scan, there is no concept of a missed dose. If a scan is missed, simply reschedule the appointment.
Overdose of a diagnostic radiopharmaceutical would manifest as excess radiation exposure rather than pharmacological toxicity. In the extremely unlikely event of inadvertent administration of an excessive activity, the effective dose can be reduced by encouraging diuresis (generous oral fluids, intravenous saline and, if appropriate, a loop diuretic) and frequent voiding, which promote urinary elimination of the tracer. There are no known pharmacological antidotes; none are needed.
How TechneScan MAG3 Is Given
The reconstituted 99mTc-MAG3 solution must be used within 4-6 hours of preparation because of technetium-99m decay and potential radiolysis. It is drawn into a shielded syringe, the activity is measured in a dose calibrator and the dose is administered as a rapid intravenous bolus through a pre-placed cannula. Careful technique is essential: a slow or partial injection will distort the vascular phase of the renogram and may compromise the quantitative analysis.
Imaging begins simultaneously with the injection. The patient lies supine under a gamma camera that views the back (for native kidneys) or the front of the abdomen (for transplanted kidneys). The acquisition usually lasts 20-30 minutes. If a diuretic renogram is performed, an additional 20 minutes of imaging follows the furosemide injection. For captopril renography, the full acquisition is usually repeated on a separate day (or a one-day protocol with a lower first dose) after captopril administration.
TechneScan MAG3 is handled only by staff trained in radiopharmacy and nuclear medicine, in facilities licensed for the receipt and administration of radioactive medicinal products. Storage, preparation, administration and waste disposal must comply with national and European radiation protection legislation (EU Basic Safety Standards Directive 2013/59/Euratom or equivalent national regulations).
What Are the Side Effects of TechneScan MAG3?
Clinical experience accumulated over more than three decades of use, together with post-marketing pharmacovigilance, confirms that TechneScan MAG3 has an excellent safety profile. Because the amount of chemical substance administered is only a few micrograms, true pharmacological adverse reactions are very unusual, and the risk profile is dominated by non-specific reactions to intravenous injection, rare allergic responses and the low-dose ionising radiation that is inherent to all nuclear medicine procedures.
Overview of Adverse Reactions
Very Common
May affect more than 1 in 10 people
- None identified in clinical practice
Common
May affect up to 1 in 10 people
- None identified in clinical practice
Uncommon
May affect up to 1 in 100 people
- Transient nausea or dizziness shortly after injection
- Pain, warmth or bruising at the injection site
- Vasovagal reaction (lightheadedness, brief drop in blood pressure)
- Transient metallic taste in the mouth
- Urgency to urinate during imaging (particularly after furosemide)
Rare
May affect up to 1 in 1,000 people
- Mild allergic or hypersensitivity reactions (rash, itching, urticaria)
- Flushing or chills shortly after injection
- Transient headache
- Palpitations or mild tachycardia
Very Rare / Not Known
May affect up to 1 in 10,000 people or frequency not estimable
- Anaphylaxis or severe hypersensitivity reaction
- Angioedema
- Bronchospasm
- Extravasation at the injection site with local inflammation and elevated local radiation dose
- Long-term stochastic risk from the small radiation dose (cancer induction, hereditary effects), estimated to be very low
Reactions Related to the Examination Procedure
Some adverse effects recorded during a renal scintigraphy are not caused by the radiopharmaceutical itself but by the pharmacological challenge used alongside it:
- Furosemide (diuretic renogram): Produces brisk diuresis and urgency to urinate; may cause transient postural hypotension and, rarely, allergic reactions in patients with sulphonamide hypersensitivity.
- Captopril (captopril renogram): Can cause a significant drop in blood pressure, especially in patients with bilateral renal artery stenosis or volume depletion. Blood pressure is monitored during the procedure, and intravenous fluids must be available.
Radiation-Related Considerations
According to ICRP Publication 128, the effective dose from a typical 100 MBq adult 99mTc-MAG3 renal scan is approximately 0.7 mSv, rising to about 1.4 mSv for the higher activities used in quantitative studies. This is comparable to roughly 3-6 months of average natural background radiation and is substantially lower than the dose from a typical abdominal CT scan (around 8-10 mSv). The organ receiving the highest absorbed dose is the bladder wall, which is why generous fluid intake and frequent voiding after the scan are recommended - these measures can reduce bladder dose by up to 50%.
The risk-benefit balance is particularly important in children and women of childbearing age. Paediatric dose cards, modern gamma cameras and optimised acquisition protocols keep the radiation dose to a child at levels similar to an adult renal scan. In suspected pregnancy, the scan is postponed, replaced with non-ionising imaging or performed only when absolutely necessary and with the lowest possible activity.
If you experience any side effects, including those not listed here, tell your doctor or the nuclear medicine team. You can also report suspected side effects to your national pharmacovigilance authority (for example, the EMA EudraVigilance system in Europe, the FDA MedWatch program in the United States, or the MHRA Yellow Card Scheme in the United Kingdom). Reports help the ongoing monitoring of the benefit-risk profile of this medicine.
How Should TechneScan MAG3 Be Stored?
As with all radiopharmaceuticals, storage of TechneScan MAG3 is the responsibility of the licensed nuclear medicine facility and its radiopharmacy. The key requirements are:
- Unlabelled kit: Store at 2 °C to 8 °C in the original carton to protect from light. Do not freeze. Do not use after the expiry date printed on the label - the expiry date refers to the last day of that month.
- Reconstituted injection: After labelling with sodium pertechnetate (99mTc), store the final injection below 25 °C, protected from light. Use within the in-use shelf-life specified in the product leaflet, typically 4-6 hours, to ensure adequate radiochemical purity.
- Visual inspection: Before use, check that the solution is clear and free of particulate matter. Discard the preparation if there is any discolouration or visible contamination.
- Radiation shielding: Vials and syringes containing 99mTc must be kept in appropriate lead or tungsten shielding to minimise occupational radiation exposure.
- Disposal: Any unused radiopharmaceutical or contaminated waste must be stored in a designated decay area until the activity has fallen below regulatory exemption levels, and then disposed of according to national legislation. Radioactive waste must never be discharged via domestic waste or wastewater.
Patients do not take any part of this medicine home and therefore do not need to manage storage themselves. After the scan, no special precautions beyond normal hygiene are usually required; nuclear medicine staff will give tailored advice if close contact with pregnant women or small children is anticipated during the first few hours.
What Does TechneScan MAG3 Contain?
Active Substance
The chemical precursor in each TechneScan MAG3 vial is betiatide (S-benzoyl mercaptoacetyltriglycine), a small peptide-like molecule that acts as a chelator for technetium. When the vial is reconstituted with sodium pertechnetate (99mTc) injection, the stannous ion reduces Tc(VII) to the oxidation state needed for complexation, and the benzoyl protecting group is released, producing the final active radiopharmaceutical technetium (99mTc) mertiatide, commonly abbreviated as 99mTc-MAG3.
Inactive Ingredients (Excipients)
- Stannous chloride dihydrate (reducing agent)
- Sodium tartrate dihydrate (transchelator / stabiliser)
- Disodium tartrate (buffer)
- Lactose monohydrate (cryoprotectant for lyophilisation)
- Hydrochloric acid or sodium hydroxide (for pH adjustment during manufacture)
Radioactive Component (Added at Preparation)
The radionuclide technetium-99m (99mTc) is a metastable isomer of technetium-99 that decays to the ground state with a physical half-life of 6.02 hours, emitting gamma rays of 140 keV. It is obtained by elution from a 99Mo/99mTc generator in the form of sodium pertechnetate (99mTc) injection, which complies with the European Pharmacopoeia monograph for the product. The final administered dose contains only nanogram quantities of technetium, but this is sufficient to produce clear gamma-camera images.
Appearance
TechneScan MAG3 is supplied as a white to off-white lyophilised powder (freeze-dried cake) in a glass vial closed with a rubber stopper and aluminium crimp cap. After reconstitution, the solution is clear and colourless, with a pH in the range of approximately 5-7. Each carton contains five single-use vials for multiple patient preparations.
Manufacturer and Marketing Authorisation
TechneScan MAG3 is manufactured and marketed by Curium Netherlands B.V. (previously known as Mallinckrodt Medical B.V.), Petten, The Netherlands. Marketing authorisation is held at the national level in most European countries and under equivalent regulatory pathways in many other jurisdictions. The product is supplied only to nuclear medicine facilities, radiopharmacies and distributors licensed to handle radioactive medicinal products.
Frequently Asked Questions About TechneScan MAG3
TechneScan MAG3 is a radiopharmaceutical used for dynamic renal scintigraphy - a nuclear medicine scan that shows how well each kidney works. It is used to measure split (differential) renal function, to investigate suspected obstruction of the urinary tract (often combined with furosemide in the so-called diuretic renogram), to assess renal transplants, to screen for renovascular hypertension (combined with captopril) and to monitor kidney function in patients where standard blood tests are insufficient or glomerular filtration is severely reduced.
Yes, the injected solution contains the radioactive isotope technetium-99m, which emits gamma rays that are used to create images. Technetium-99m has a short physical half-life of 6 hours and is excreted predominantly through the kidneys. A typical adult study with 100-200 MBq gives an effective dose of approximately 0.7-1.4 mSv, comparable to or lower than a routine CT scan and equivalent to a few months of natural background radiation. For a patient with normal kidneys, the kidneys receive only about 0.011 mGy per MBq and the bladder wall is the organ with the highest dose; careful hydration and frequent voiding after the scan further reduce exposure.
Side effects are extremely rare because the amount of chemical substance injected is tiny (microgram range). The most commonly reported reactions are mild and transient: nausea, dizziness, flushing, a metallic taste or brief pain and warmth at the injection site. Allergic reactions such as rash or itching are uncommon and anaphylaxis is very rare. The main long-term concern is the small theoretical risk from ionising radiation, which must be balanced against the diagnostic benefit of the scan.
During pregnancy, radiopharmaceutical imaging is avoided whenever possible. Pregnancy must be excluded in women of childbearing age before the scan, and alternatives such as ultrasound or MRI are considered first. TechneScan MAG3 is used in pregnancy only when the diagnostic information cannot be obtained in any other way and the benefit clearly outweighs the radiation risk to the fetus. In breastfeeding women, breastfeeding should be interrupted for at least 4 hours after administration, with milk expressed during this period discarded; for very high administered activities, a longer interruption may be recommended by the nuclear medicine team.
Expect to be in the nuclear medicine department for 1-2 hours. You will be asked to drink approximately 500 mL of water before the scan and to empty your bladder just beforehand. A cannula is placed in a vein in your arm. You will then lie on the scanning table, usually on your back, and the gamma camera will be positioned close to you. At the moment of tracer injection, the imaging starts; dynamic image acquisition lasts about 20-30 minutes during which you must lie very still. If a diuretic (furosemide) or ACE inhibitor (captopril) is used, the appointment is longer. The scan is painless apart from the initial cannula insertion; you can eat and drive normally afterwards.
It depends on the type of renogram. For a routine dynamic renal scan, you will usually continue all your regular medications. For a captopril-enhanced renogram (for suspected renovascular hypertension), ACE inhibitors and angiotensin receptor blockers are usually stopped 48-72 hours before the test, and diuretics may be paused for 24 hours. For a diuretic renogram, ongoing loop diuretic therapy is usually withheld for 24 hours. You should not stop any medication on your own - the referring physician and the nuclear medicine team will give you specific instructions based on the reason for the scan.
All three are technetium-99m radiopharmaceuticals used for kidney imaging, but they are handled differently by the kidney. MAG3 is cleared predominantly by tubular secretion and is the tracer of choice for dynamic studies of split function, obstruction and transplants, even when kidney function is reduced. DTPA is cleared only by glomerular filtration and is therefore used when a true measurement of GFR is wanted, but performs poorly when filtration is impaired. DMSA binds to the renal cortex and is used for static imaging of the kidney parenchyma, for example to detect scars after pyelonephritis or to identify congenital anomalies. The choice depends on the clinical question and is made by the nuclear medicine physician.
References
- European Medicines Agency (EMA) – National Competent Authorities. TechneScan MAG3 Summary of Product Characteristics (Curium Netherlands B.V.). Last updated 2024.
- European Association of Nuclear Medicine (EANM). Procedure guideline for Tc-99m-MAG3 scintigraphy version 3. Gordon I, Piepsz A, Sixt R, et al. Eur J Nucl Med Mol Imaging. 2011;38(6):1175–1188. doi:10.1007/s00259-011-1811-3.
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- Taylor AT, Brandon DC, de Palma D, et al. SNMMI procedure standard/EANM practice guideline for diuretic renal scintigraphy in adults with suspected upper urinary tract obstruction 1.0. Semin Nucl Med. 2018;48(4):377–390.
- Prigent A, Cosgriff P, Gates GF, et al. Consensus report on quality control of quantitative measurements of renal function obtained from the renogram: International Consensus Committee from the Scientific Committee of Radionuclides in Nephrourology. Semin Nucl Med. 1999;29(2):146–159.
- International Commission on Radiological Protection (ICRP). Radiation Dose to Patients from Radiopharmaceuticals: A Compendium of Current Information Related to Frequently Used Substances. ICRP Publication 128. Ann ICRP. 2015;44(2S):1–321.
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