Question

why technetium 99 is use as a medical tracer?

Answer 1

its radioactive with short half-ife

Answer 2

i need more than one reason

Answer 3

It has an excellent energy gamma ray for imaging.

It does not emit a high energy beta particle which would unnecessarily increase the patients radiation dose.

It can be attached to a fair number of different molecules that are treated in a special way by our bodies eg concentrate in certain organs

Short half-life (~6hrs) so re-scanning can be done after a few days.. and contaminated articles will be safe to handle in less that a week.

It can be produced in large quantities locally in a Radiology Department with generator which will last about a week and is relatively cheap..

I think that's about it.