My Radioactive Student
Yesterday a student came up to me and explained that she had been injected with a radioactive isotope for a medical scan. She then asked if she was still radioactive.
Expecting the isotope to be mostly decayed or simply too small to notice, I wanted to calm her fears with a Geiger counter check.
The results surprised me, and she allowed me to take a video (her face is not shown for privacy) shown below. You can listen carefully to the ‘clicks’, which rapidly increase as I approach her.
It turns out that her doctor gave her a note (right) explaining that the isotope was Technetium-99m – commonly used for medical scans (more information about Tc-99m can be found from the Brookhaven National Laboratories). Tc-99m has a half-life of 6 hours (she had the scan 4 hours earlier), so she still had a significant amount present in her body.
Leave it to a science teacher to find this interesting.