Is it dangerous to be an x-ray technician or a radiology technician? Yes and no...no in the sense you are trained on safety procedures an how to keep yourself and the patient safe. You have special equipment to keep you safe such as lead lined window glass and walls as well as lead aprons. You also wear a device called a Geiger meter to measure your radiation exposure and if levels get too high you are sent home an not allowed to come back until you are at normal levels.
That said it still isn't completely safe. If you dont follow safety procedures you could jeapardize your health. If equipment isn't properly maintained, properly used, and properly kept in order your health coudl be in jeapardy.
Also, despite all the safety equipment just because the machine is off doesn't mean much. Radiation particles are still in the room and in large amounts, radiation is like a fine dust. Each time the machine is used there is still radiation left in that room. In order to get rid of it all you would need to wipe down the walls, floor, and ceiling with hot soapy water or exposure is inevitable. That said those levels are low though no radiation is necesarily good you can do the job safetly.
So to answer your question is radiology tech jobs safe, yes it's pretty safe if you do the job safely however that said you are more at risk to radiation exposure than someone say working a desk job as a secretary so it is more dangerous than other jobs.
I wouln't let that keep you from ding the job though, it's a great job, pay is great, and you get to help people.