Quality control

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Radionuclide Purity

  • Degree of contaminatin from other radionuclides
  • Increase dose without contributing to image
  • Should never contribute more than 10% of dose to patient
  • Mo99 Breakthrough
    • Performed with every elution
    • Shield with Lead,740 and 780 keV of Mo will go through, 140 keV of Tc will not
    • There are also chemical tests
    • Limit of 0.15 uCi Mo99 per mCi Tc99m at time of administration

Radiochemical Purity

  • How well the label worked
  • Tested by thin layer chomatography
  • Can identify free pertechnetate

Chemical Purity

  • Al ion breakthrough
    • Degrades image quality, interferes with labeling
    • NRC limit 10ug per ml
    • Measured on color paper strip
  • Must also be Sterile and Apyrogenic

Dose Calibrator

  • Ensures constancy

Uniformity Testing

  • Makes sure counts are equal throughout the field of view
  • Performed daily
  • Flood by cobalt sheet with (extrinsic) and without (intrinsic) collimator
  • Looks for cracked crystals or failed PMT
  • Off Peak Image - can occur after daily uniformity test if Co used (keV 122) and not changed before a Tc study (140 keV), results in blur from scatter

Resolution Testing

  • Performed daily
  • Parallel lines

Center of Rotation

  • Performed weekly