Nuclear Medicine: using radioisotopes

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• Nuclear Medicine using radioisotopes

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• Some nuclides can be used "as is".
• radioactive iodine, is absorbed directly by the
  thyroid gland.
• radioactive thallium is absorbed directly by the
  heart muscle and can be used to investigate
  whether parts of the heart are functioning
  normally.

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• Most radioactive nuclides, however, must be bound
  to a carrier molecule that enables them to bind
  to the cells or processes we want to image.
• The carrier molecule has an affinity for a
  certain type of cell or receptor
• The radio-labelled molecule will home in on these
  cells and attach itself to them.

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Technetium generator
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• 99mTc binds easily to various carrier molecules.
• The trend within nuclear medicine is towards the
  development of receptor-specific carrier
  molecules which target specific organs or disease
  states,
• These molecules carry 99mTc or other
  radionuclides to the sites in the body that we
  want to image

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Collecting Tc-99m

• The generator is a column containing a resin to
  which Mo-99 is attached.
• The Mo-99 decays to produce the short-lived
  Tc-99m (6 hr half-life).
• To obtain the Tc-99m, a solution (the eluent) is
  injected into the top of the column 

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• doctors use gamma cameras to detect the tell-tale
  radioactivity and image the targeted diseased
  tissues