I 123

Radiopaedia • CC-by-nc-sa 3.0 • de

Iodine-123 (I or I-123) is a radioisotope of the element iodine (atomic number 53) used in nuclear medicine imaging including to scan the thyroid gland.

Uses, dosages, and time of Imaging

  • standard scan: 3.7-14.8 MBq (100-400 μCi) PO, image at 4-6 or 24 hours
  • thyroid cancer scan: 55.5 MBq (1.5 mCi) PO, image at 4-6 or 24 hours

Physical properties

  • photon energy: 159 keV
  • physical half life: 13.2 hours

Normal distribution

  • thyroid gland (target organ)
  • nasopharynx
  • salivary glands
  • stomach (target organ)
  • colon
  • bladder (target organ)
  • lactating breasts

Pharmacokinetics

Iodine-123 is rapidly absorbed from the gastrointestinal tract, with detectable activity in the thyroid gland within minutes. It reaches the thyroid follicular lumen in 20-30 min, with rapid trapping and organification.

Excretion

Excretion is primarily renal. It should be noted that it is also secreted in breast milk and crosses the placenta. As such it is contraindicated in pregnancy and requires precautions if breast feeding.

Imaging technology
Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu I 123:
thyroid scan
(I-123)
Wikipedia • CC BY-SA 4.0