Sodium pertechnetate(99mTc) is a sterile, colorless solution in normal saline (0.9%NaCl), obtained by elution of the sterile Mo–99/Tc-99mgenerator. The major use of sodium pertechnetate (99mTc) isthe preparation of various technetium-99m radiopharmaceuticalseither in a nuclear pharmacy or nuclear medicine department.On-site preparation of radiolabeled red blood cells(RBCs) requires the availability of sodium pertechnetatesince the radiolabeled cells must be reinfused to the patientwithin 30 minutes of preparation.
The pertechnetate ion (99mmTcO4-), which has an ionic radiusand charge similar to the iodide ion (I-) and is concentratedin the thyroid, salivary glands, kidneys, stomach, andchoroid plexus in the brain. It can be used in a diluted solutionfrom the Mo–99/Tc-99m generator elution to image the thyroid, Meckel’s diverticulum (stomach tissue in the intestine),salivary glands, and to detect processes that disrupt theblood-brain barrier (i.e., tumors, abscesses, strokes).
Like iodide, pertechnetate is trapped by the thyroid.Pertechnetate, however, cannot be utilized to prepare thyroidhormone. The patient receives an intravenous injectionof 5 to 10 mCi (185–370 MBq) of Tc-99m pertechnetate,and thyroid images are obtained 20 to 30 minutes after injection.The usual dose for other imaging procedures such asMeckel’s diverticulum and salivary gland imaging is also 5to 10 mCi (185–370 MBq), whereas 20 mCi (740 MBq) isused for blood-brain barrier imaging.
