Adding to problems:
*short half life of of Tc-99m (6 hours) means it might have transport problems, particularly for rural/country hospitals. (also hence why they pack it as *something*, as to let it decay into Tc-99m.)
*althought it's a small dose, even such a small amount of radiation can be (unknowingly) harmful
Edit for forbidden. instead of "blood pool" it might be better to say it can be used to check for circulation problems.
...Sorry I don't have my notes with me. I have quite good info on it also Forbidden has done an excellent job
.