Radiochemist here. Tc-99m is a so-called generator produced isotope. It is a decay product of Mo-99 (half-life 66h) which is produced via fission of U-235 (around 6% of the fission products is Mo-99). Mo-99 is separated from U-235 and afterwards bound to a stationary/solid phase. There it decays constantly to Tc-99m. Due to the different chemical nature of Mo and Tc you can easily elute the Tc-99m for preparation of the radiopharmaceutical. Hospitals have these Mo-99/Tc-99m generators on site and elute them every day. As the Mo-99 decays these generators needs to be replaced after 1-2 weeks. After elution of the Tc-99m the radiopharmaceutical is then usually prepared via a kit. It is like a pre-made mix where you just need to add the Tc-99m, shake for a minute and it's ready to use for patients.
radioactive_giraffe t1_j6zc8sg wrote
Reply to A medical isotope made from nuclear weapons waste (Tc-99m) has a six-hour half-life. How do hospitals keep it in stock? by Gwaiian
Radiochemist here. Tc-99m is a so-called generator produced isotope. It is a decay product of Mo-99 (half-life 66h) which is produced via fission of U-235 (around 6% of the fission products is Mo-99). Mo-99 is separated from U-235 and afterwards bound to a stationary/solid phase. There it decays constantly to Tc-99m. Due to the different chemical nature of Mo and Tc you can easily elute the Tc-99m for preparation of the radiopharmaceutical. Hospitals have these Mo-99/Tc-99m generators on site and elute them every day. As the Mo-99 decays these generators needs to be replaced after 1-2 weeks. After elution of the Tc-99m the radiopharmaceutical is then usually prepared via a kit. It is like a pre-made mix where you just need to add the Tc-99m, shake for a minute and it's ready to use for patients.