[Timemachine1 (OP)]

Or focused to ionize neurons in the brain at micron cubic ranges.[/size]I have been told that gamma beams cannot work with ball lenses, but X-rays, and other electromagnetic radiation, I am unsure about.how much can gamma knife beams be collimated without using ball lenses.What would be the smallest cubic area in the brain you could ionize, without gamma beams passing through a ball lens.Can you tell me the effects for X-Rays, and other electromagnetic radiation, if they can pass through a ball lens or not.If you can ionize neurons at micron scales you can stop the spread of Parkinson's disease throughout the brain.It would be tricky, and complex, but not impossible.You could probably erase memories specifically in an animal also, with this technique.Thank you for your help with this question. [/color]

[alancalverd]

You cannot focus gamma or hard x-rays. Selective diffraction can increase the local intensity of soft x-radiation  but it is of no use therapeutically. You can cook a 1 mm sphere fairly accurately with a Cyberknife but only at a depth of about 1 cm inside the brain.

[Bored chemist]

As long as you are prepared to put up with huge inefficiencies, you can collimate a gamma ray beam.
If you drilled a 1 micron diameter hole through a metre thick lead block and put a very intense gamma source behind it, you would get a beam that only diverged by a micron or so over the course of a metre.

It would need a phenomenally powerful source to achieve anything because only about 1 in ten million million gamma photons would go through the hole.

What good would it do you?
Well, not a lot because as soon as the beam hit anything- like the skin or the skull- it would start to spread out.
By the time it got into the brain it wouldn't be a 1 micron wide beam any more.
That's why this idea has never been used in practice, and never will be.

[PmbPhy]

Or focused to ionize neurons in the brain at micron cubic ranges.[/size]I have been told that gamma beams cannot work with ball lenses, but X-rays, and other electromagnetic radiation, I am unsure about.how much can gamma knife beams be collimated without using ball lenses.What would be the smallest cubic area in the brain you could ionize, without gamma beams passing through a ball lens.Can you tell me the effects for X-Rays, and other electromagnetic radiation, if they can pass through a ball lens or not.If you can ionize neurons at micron scales you can stop the spread of Parkinson's disease throughout the brain.It would be tricky, and complex, but not impossible.You could probably erase memories specifically in an animal also, with this technique.Thank you for your help with this question. [/color]

I don't know about gamma rays but I do know about x-rays. In fact the Chandra X-Ray Observatory which is currently in orbit collimates X-Rays does this. See:
http://chandra.harvard.edu/about/

Chandra carries four very sensitive mirrors nested inside each other. The energetic X-rays strike the insides of the hollow shells and are focussed onto electronic detectors at the end of the 9.2- m (30-ft.) optical bench. Depending on which detector is used, very detailed images or spectra of the cosmic source can be made and analyzed.

I actually worked on this telescope. I worked at MIT in a lab where the CCDs were being calibrated. I was a technician there.