Do you mean a thallium heart stress test? And it's a week later? That'd be some geiger counter, but anything's possible. It usually flushes from the system pretty quickly, or so I was told when I had mine.
I had that test,They told me not to use their bathroom after the test.
Often, instead of Thallium, they use Technetum-99 (Tc99) for the scan. This element is usually the product of bombarding molybdenum-99 with neutrons using a cyclotron.
Also, Tc99 can be used for brain, bone and other medical scans. I remember undegoing a nuclear cell survival study using an isotope of chromium. This was in conjunction with a centrifuge study for human physiology.