[illl (OP)]

I was wondering is lead glass sufficient protection for physicians using CT scan,non-invasive fluoroscopy etc. are there any penetrating stray x-rays through the lead barriers,and are they making it more dangerous to practice. : ) 

[evan_au]

Shielding of the X-Ray source itself aims to ensure that X-Rays only travel in the direction of the patient - and only towards the body part(s) of interest.

Positioning the X-Ray source close to the patient (cm) while the operating staff are distant (meters) reduces the intensity for the radiographer by a factor of 1000 or so.

Modern detection methods are far more sensitive than the old photographic film, so exposure times today are shorter.

There are multiple carcinogenic sources in our environment, in our diet, in radioactive rocks and radioactive food (eg bananas and Brazil nuts), during air travel and in our metabolism.

So the idea  of the lead glass is not to reduce the exposure to zero, but merely to reduce it to a level which is insignificant compared to the other risks to which we are exposed.

In the early days of radiography, the risks of X-Ray exposure were not understood, and shielding was not used. I heard an anecdote that the risks were first realized at an early conference on radiology, where many radiologists gathered in one hotel. They had chicken for dinner, but a large number of radiologists could not eat it, because it required manipulating a knife and fork, and there were a huge proportion of amputees among the conference participants.