Tc-99m sulfur colloid

Radswiki et al.

Technetium-99m sulfur colloid is one of the technetium radiopharmaceuticals.

Characteristics

  • photon energy: 140 keV
  • physical half-life: 6 hours
  • biological half-life
  • normal distribution:
    • liver: 85%
    • spleen: 10%
    • bone marrow: 5%
  • excretion: hepatic
  • target organ: liver, spleen
  • pharmacokinetics:
    • rapid extraction by liver, spleen, and bone marrow
    • active bleeding increases in conspicuity as background clears
    • small colloid particles (0.1-1.0 micrometer) extracted by RES
    • localization is flow-dependent
    • taken up by Kupffer cells in the liver
  • miscellaneous facts

Uses, dosages and timings

Lymphoscintigraphy
  • dose: 4-8 injections of 100 uCi injected intradermally
    • encircling the lesion site for a melanoma study
    • in the webs of the fingers and toes for a lymphatic mapping study
  • time of imaging: immediately after the last injection
Gastric emptying scan
  • adult dose: 1 mCi in meal
    • a meal of chicken liver was the original gold standard, but it is more common to use a scrambled egg, oatmeal, pancake, or an egg sandwich; many things have been used and each facility decides what should be defined as a normal meal for their patients
  • paediatric dose: 30-50 uCi/kg (min 500 uCi)
  • time of imaging: immediate
  • length of imaging: 2-4 hours
Liver / spleen scan
  • adult dose: 4-8 mCi IV
  • paediatric dose: 30-50 uCi/kg (min 300 uCi)
  • time of imaging: 20 min
Gastrointestinal tract bleeding
  • adult dose: 10 mCi IV
  • time of imaging: immediate (1 sec frames x 60 sec; 1-2 min frames x 20 min)

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Article Information

rID: 12394
Section: Physics
Synonyms or Alternate Spellings:
  • Tc-99m sulphur colloid
  • Tc-99m sulfur colloid
  • Technetium-99m sulfur colloid

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