Tc-99 ( I have seen at DOE facilities) is a beta emitter with a long half life, Tc-99m emits alot of gamma and is used in imaging studies at hospitals with a 6 hour half life. Sometimes people look at these and think apples to apples but it really is apples to oranges when looking at emmisions from these.
Here is a Wikipedia on Tc-99, It does mention soft X-rays from Laboratory glass. I did not know that. So the comment on X-rays seems valid.
Technetium-99
From Wikipedia, the free encyclopedia
Technetium-99 (99Tc) is an isotope of technetium which decays with a half-life of 211,000 years to stable ruthenium-99, emitting soft beta rays[1], but no gamma rays.
Technetium-99 has a fission product yield of 6.0507% for thermal neutron fission of uranium-235, making it the most significant long-lived fission product of uranium fission, with a half-life over 2000 times as long as the next longest-lived fission product.
The weak beta emission is stopped by the walls of laboratory glassware. Soft X-rays are emitted when the beta particles are stopped, but as long as the body is kept more than 30 cm away these should pose no problem. The primary hazard when working with technetium is inhalation of dust; such radioactive contamination in the lungs can pose a significant cancer risk.
Technetium-99m is a short-lived (half-life about 6 hours) metastable nuclear isomer used in nuclear medicine, produced from molybdenum-99. It decays by isomeric transition to technetium-99, a desirable characteristic, since the very long half-life and type of decay of technetium-99 imposes little further radiation burden on the body.
