I-123

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Contents

[edit] Photon energy

159 keV

[edit] Uses, dosages, and Time of Imaging

  • Routine scan: 100-400 microCi po, image at 4-6 or 24 hours
  • Thyroid cancer scan: 1.5 mCi po, image at 4-6 or 24 hours

[edit] Physical half life

13.2 hours

[edit] Biological half life

[edit] Normal distribution

Thyroid, nasopharynx, salivary glands, stomach, colon, bladder, lactating breasts

[edit] Pharmacokinetics

  • Rapidly absorbed from GI tract; detectable activity within gland in minutes
  • Reaches thyroid follicular lumen in 20-30 min
  • Trapping and organification rapid
  • Delayed imaging for background clearance
  • Image at 6 and 24 hours; 10-30% uptake at 24 hours

[edit] Excretion

Renal

[edit] Target organ

Thyroid, bladder, stomach, SI

[edit] Other

  • Secreted in breast milk
  • Crosses placenta
  • May cause cretinism