What kind of radioactive material is used in radiotherapy? If it was stolen could it harm anyone?

And what security measures do hospitals take to prevent this?

There are two methods for administering radio therapy treatment. The first is External Radiation and this uses ionizing radiation to kill cancer cells or tumours. This DOES NOT have any radioactive materila associated with the treatment what so ever.
The other type of treatment is internal radiotherapy (Systemic radiation therapy) and this uses radioactive materials such as iodine 131 and strontium 89. Both of these have a fairly short half life of approx. 8 and 50 days respecively. So unlikely to be much of an issue, although security would be fairly stringent surrounding any forms of radiocative materials and medicines.

It used to be Radium ,but it may have changed by now.Any radiation can be dangerous over a period of time.

Return it bro; just take it back. It's not right what you done.

Your search ends at below site. Have a look at it. It will definitely help you out

http://lnk.in/5723

It kills cancerous cell as well as normal cell also.
bcoz of that care must be taken for that.

Lets see...in the older machines still in use it is cobalt 60

Now it really isn't anything, a high energy beam is sent through a machine and it hits a target and the atoms are split and the photon are the radiation energy.

No more sources in the current machines

Depending on the isotope and a few hundred other variables it could cause some very serious damage to a person. I have no idea about hospital security, but I strongly suspect that the knock on your door is the FBI. Enjoy your prison cell.