Tc-99m

Technetium-99m (Tc-99m) is a metastable radioactive isotope of technetium with a half-life of approximately 6 hours. It decays to technetium-99 (Tc-99) by emitting gamma radiation, which is highly useful in medical imaging due to its ideal energy (140 keV) and short half-life, minimizing radiation exposure to patients. Tc-99m is derived from the decay of molybdenum-99 (Mo-99), typically produced in nuclear reactors.

Tc-99m is widely used in nuclear medicine as a radiopharmaceutical. It is a key isotope in diagnostic imaging, particularly for single-photon emission computed tomography (SPECT) scans. Tc-99m is employed to image various organs and systems, including the heart (myocardial perfusion), bones, lungs, liver, kidneys, and thyroid. Its versatility and the ability to label different compounds make it suitable for detecting diseases like cancer, heart disease, and bone disorders. Tc-99m is also used in sentinel lymph node detection during surgeries for cancers such as breast cancer.

Tc-99m does not occur naturally and is produced in specialized facilities. It is obtained from technetium generators that extract Tc-99m from the decay of Mo-99. These generators are distributed to medical facilities, allowing Tc-99m to be readily available for imaging procedures. Tc-99m is encountered primarily in controlled medical environments, such as hospitals and nuclear medicine clinics, where it is used under strict regulations to ensure safety for both patients and medical staff.