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Renal Study

Renal DTPA or MAG3 Study


  • You have been referred for a Renal DTPA or Renal MAG3 study to look at the blood supply, function and excretion of urine from your kidneys.

  • The test can assess what percentage each kidney contributes to your total kidney function.

  • The test may also be undertaken to evaluate:

    • Renal tubular function and perfusion (how body fluids circulate through the kidneys)

    • Renovascular hypertension (high blood pressure in the arteries of the kidneys) - Renal Captopril Study

    • Renal artery stenosis (narrowing of the arteries that take blood to the kidneys) - Renal Captopril Study

    • Renal tubular obstruction and trauma or damage (blockage or interruption of the ureters)

    • Renal Transplant function (viability, obstruction, urinary leaks)

  • Upon arrival to the department, you will be asked to empty your bladder.

  • You then will be asked to lie on a scanning bed with a Gamma camera(1) placed under the bed.

  • A small cannula or butterfly needle is then injected into a vein in your arm.

  • A small amount of tracer called 99mTc-DTPA (99m-Technetium diethylene-triamine-penta-acetic acid) or 99mTc-MAG3 (99m-Technetium mercaptoacetyltriglycine) is injected via this cannula.

  • 99mTc-DTPA is cleared by glomerular filtration.

  • 99mTc-MAG3 is cleared by glomerular filtration and tubular excretion (useful if renal function is impaired or in children aged 0 - 3 months).

  • There are rarely any side effects with either injection.

  • Imaging of your kidneys occurs as soon as the tracer has been injected.

  • ​Imaging can take anything from 15 to 30 minutes.

  • If either kidney shows hold-up of tracer, additional imaging is usually required whereby a diuretic ('Lasix' or Frusemide) is given. This imaging takes 15 minutes to complete.

  • ​You will be requested to empty your bladder before and after the diuretic is given.

  • 1 minute images are usually done after you have emptied your bladder.

  • Renal Captopril Study: Usually two Renal DTPA studies are required to make a diagnosis:

    • First Study [Captopril Study]: One hour prior the Renal DTPA study, 50mg of Captopril and 10mls/kg of water is consumed over the hour. The Renal study is then performed as per normal.

    • Second Study [Baseline Study]: Repeat the Renal DTPA study 2 days after the Captoptil study. NO Captopril is taken and 10mls/kg of water is consumed over one hour prior imaging. The Renal study is then performed as per normal.

    • Note: For both studies you should abstain from taking any ACE Inhibitors (3). Alternate medications may be arranged by your doctor.

  • You receive a slight radiation dose by having a Renal DTPA Study (or MAG3 Study) ~ up to 1.3 times your yearly background radiation (2).


Patient Preparation:

  • If you are pregnant, trying to fall pregnant or breast feeding, you must inform our staff.

  • You are required to drink three glasses of water before you arrive for your Renal Study (unless your doctor has placed you on "Fluid Restrictions").

  • Renal Captopril Study: If your study is being done to evaluate Renal Hypertension or Renal Artery Stenosis, ACE Inhibitors (3) should be stopped 4 - 7 days prior to the examination. Alternate medications may be arranged by your doctor. For any further queries, please contact us to discuss your preparation.

  • If you have had prior imaging e.g. PET, Nuclear Scan, CT, MRI, X-Ray, Ultrasound, etc... please bring these with you.

  • Please also bring your referral and any blood results that you may have had done.

  • Wear comfortable clothing and minimise the amount of metal jewellery you have on (all metal objects will need to be removed prior to imaging).

  • Important Note: You cannot have this test if you have had a PET or Nuclear Scan within 24 hours prior to this test. If you have had Iodine-131 therapy, allow 4-weeks before having this test. Please ring to discuss booking options.​


Breast-Feeding Mothers: Once you have been given the tracer, you need to stop breast-feeding for two feeds. During this time, you need to express and discard your breast milk. You will need to bottle-feed your child during this period.



(1) A Gamma Camera is a device that detects gamma-rays (gamma-rays are very similar to x-rays) and does not emit any radiation.

(2) We all receive a yearly background radiation dose ~ 2.4mSv. Renal DTPA Study (or MAG3 Study) ~ 3.1mSv = 1.29 times yearly background dose.

(3) List of ACE Inhibitors (angiotensin-converting-enzyme inhibitors) inlude but not limited to: Accupril, Aceon, Altace, Amprace, Asig, Benazepril, Capoten, Captopril, Enalapril, Fosinopril, Lisinopril, Lotensin, Mavik, Moexipril, Monopril, Perindopril, Prinivil, Quinapril, Ramace, Ramipril, Renitec, Trandolapril, Univasc, Vasotec, Zestril.

value. quality care. convenience.

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