Tc-99m MAG3

Changed by Daniel J Bell, 12 Mar 2019

Updates to Article Attributes

Body was changed:

Tc-99m MAG3 (mercaptoacetyltriglycine) is one of the technetium radiopharmaceuticals used in renal imaging.

Characteristics

  • photon energy: 140 KeV
  • physical half life: 6 hours
  • biological half life: 4 hours
  • normal distribution: kidneys (100%)
  • pharmacokinetics:
    • uptake by tubular secretion (97%)
    • first pass filtration 60%
  • excretion: renal via both glomeruli infiltrationglomerular filtration and tubular excretion; hence, in paediatric patients and patients with poor renal function this test is considered superior to DTPAscan scan
  • target organ: bladder
  • miscellaneous facts
    • good quality images with renal insufficiency
    • by giving captopril, MAG3 plasma clearance decreases in hypertensive patients with renal artery stenosis but increases in patients without renal artery stenosis
    • cannot measure GFR as it is cleared almost entirely by tubular secretion

Uses, doses and timings

  • renal study
    • adult dose: 296 MBq (8 mCi) IV
    • paediatric dose: 3.7 MBq/kg (0.10 mCi/kg) (minimum: 14.8 MBq (0.4 mCi)) 5
    • 60 sec flow study; then q5minevery 5 min for 25 min
  • -<li>excretion: renal via both glomeruli infiltration and tubular excretion; hence, in paediatric patients and patients with poor renal function this test is considered superior to <a href="/articles/gd-dtpa-labeled-albumin">DTPA </a>scan</li>
  • +<li>excretion: renal via both glomerular filtration and tubular excretion; hence, in paediatric patients and patients with poor renal function this test is considered superior to <a href="/articles/gd-dtpa-labeled-albumin">DTPA</a> scan</li>
  • -<li>cannot measure GFR as it is cleared almost entirely by tubular secretion</li>
  • +<li>cannot measure <a title="Estimated glomerular filtration rate (eGFR)" href="/articles/estimated-glomerular-filtration-rate">GFR</a> as it is cleared almost entirely by tubular secretion</li>
  • -<li>60 sec flow study; then q5min for 25 min</li>
  • +<li>60 sec flow study; then every 5 min for 25 min</li>

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