An element that can make bones glow

In another life I used to prepare Tc99m injections for various scans and we'd call the ligands by their intended target (e.g. lung, heart etc). We'd measure the dose according to the expected time of administration in order to account for the expected decay. Our generators came from a place outside London and we would 'elute' with saline to extract the Tc.

We didn't just deal with human patients and often tagged the white cells of race horses in order that their veterinarian could detect points of infection with a gamma camera because the white cells, once re injected into the animal would quickly migrate to the nearest infection in order to join the fight.

Contamination was rare because Tc has such a short half life but the same was not true for Fe 59 and the various Iodine isotopes. Hilariously two colleagues were once tested by the monthly inspection team and were compelled to dispose of their trousers because of contamination... The mind boggles.