Question

What are the biological and radiological properties of xeon 133 and Gallium 67. For radiological imaging with the gamma camera.

Answer 1

Gallium 67 is a photon-emitting radiotracer which is used in the form of various salts like citrate and nitrate. Once administered, imaging may consist of planar (2 dimensional) , SPECT, and SPECT/CT acquisitions. Once injected it binds to plasma proteins (especially transferrin), and has a predilection to sites of inflammation. It binds to inflammatory proteins and thus it pools up at the sites of various inflammatory and granulomatous reactions.

Radionuclide profile

• emits a spectrum of gamma rays (93, 185, 288, 394 KeV energy)
• half life is about 78 hours
• critical organ: colon
• normal distribution is seen in the liver, bone marrow and spleen.

Xenon-133 is a radiopharmaceutical principally used when a performing VQ scan. Inhalation of this gas can also be used to assess cerebral blood flow.

• photon energy: 81 KeV
• physical half-life: 5.27 days
• biological half-life: 30 seconds
• normal distribution: lungs
  • <15% of inhaled gas is absorbed
• excretion: lungs
• target organ: lungs

Xenon-133 is a fission product from uranium-235. The gas is normally supplied in a concentration of 5% with 95% carbon dioxide.