technetium99mlabeled

Technetium-99m labeled compounds are radiopharmaceuticals used in diagnostic nuclear medicine. They consist of the radioactive isotope technetium-99m bound to a ligand that directs the compound to a target tissue or physiological process. The resulting radiopharmaceuticals emit gamma rays suitable for detection by gamma cameras or SPECT cameras, enabling functional imaging alongside anatomy.

Technetium-99m has a half-life of about six hours and emits 140 keV gamma photons, providing high image quality while limiting radiation dose. Most Tc-99m is obtained from a molybdenum-99/technetium-99m generator. The pertechnetate form (TcO4-) is reduced and complexed with the ligand during kit-based labeling, generating a tissue-targeted radiopharmaceutical. The wide availability of ready-to-use kits has facilitated standardized labeling for many clinical indications.

Applications include bone imaging with Tc-99m radiophosphates (e.g., MDP/HDP) for fractures or metastases; myocardial perfusion imaging with Tc-99m sestamibi or tetrofosmin; renal imaging with Tc-99m MAG3 or DTPA; hepatobiliary and gallbladder imaging with Tc-99m mebrofenin or disofenin; thyroid imaging with Tc-99m pertechnetate; brain perfusion imaging with Tc-99m HMPAO; and infection or inflammation imaging with Tc-99m-labeled leukocytes.

Safety and regulation: Radiopharmaceutical doses are small, and exposure is monitored. Handling and preparation are performed by trained personnel under strict quality control and regulatory oversight.