Updated Gamma Knife Question, Thought of Something New.

Doesn't it stand to reason that less holes and less beams means reduced exposure? So the direction, if any, that you should be taking, is more beams with smaller aperatures, to maintain the necessary exposure dose required for results....but then you begin to see that there is a limited space available with current methods, especially when we're talking 1000+ beams....The beam size would have to be smaller than the desired 0.1mm....and for each beam you need a piece of cobalt....If you can get 4 mm area with 192 beams, how many do you need for 0.1 mm.....I get 40*192=7680....

However many beams you need for the amount of neurons that need to be eliminated in that area.

I am thinking, more beams makes a bigger meet area in the center, even if they are thin beams of Gamma radiation they will still make a big meet area in the center, if you use a lot.

I am not sure of how much dose is needed to eliminate neurons, or a tumor.

GA, Solar. This is precisely the crux that Nicholas does not understand. He has no understanding of either the Physics or the Chemistry of how ionizing radiation effects living tissue.

I doubt he understands the Physics of how Cobalt-60 produces the 1.3 Mev gamma radiation itself. He clearly has no understanding how one collimates light at these energies.

This is a complete non-starter pipe dream.

For anyone interested, there is some very preliminary work being done on gamma ray optics.

This would seem to be true, but everyone has to start someplace, and motivation is key....A highly motivated student is something to be nurtured...

The more beams you have, the less radiation you get where you don't want it. However, there is a practical limit on number of beams due to cost and space restraints.

I wouldn't entrust you with so much as a butter knife.

Duplicate thread alert.

The answer is still no. See previous thread.

If you can achieve the resolution to image it, you should be able to achieve the resolution to "cut" it. Keep in mind that that, if achievable, this will still be a difficult problem. (That's one reason it's so interesting.)

CT and MRI already expose the patient to radiation, so your gamma knife will only be adding to that dose. Remember, radiation damage is cumulative. There is an upper lifetime limit. CT and MRI image from all directions in order to minimize dosage, among other reasons. Is your gamma knife going to re-expose those exact same areas?

Also, keep in mind that CT and MRI only work because of sophisticated computer programming and controls. Like CT and MRI, your knife is not going to be firing all of its beams at the same time. Emitters will be positioned, they will be energized then de-energize, then the re-positioned, energized, de-energized, and repeat until desired dose is delivered.

The patient will have to be restrained for a long time. Because of the extremely small volume you want to treat, I imagine you will have to fix the target site so that it cannot move in relation to the imager's reference points, then administer the gamma knife without moving the patient at all. Post-operative imaging will be required to determine effectivity. That person aint going anywhere for a while.

But the CT, MRI and Gamma Knife are all different types of radiation.

CT is created from X-ray radiation,

http://en.wikipedia.org/wiki/X-ray_computed_tomography

while the MRI subjects the patient to a very strong magnetic field to align the water molecules and then subjected to impulse RF radiation to excite those molecules, that then causes changes in the magnetic flux that is received to image the protons of the water. There is no ionizing radiation in an MRI,

http://en.wikipedia.org/wiki/Physics_of_magnetic_resonance_imaging

and the Gamma Knife as suggested by the name uses ionizing radiation in the form of gamma rays from the decay of radioactive cobalt to achieve its effects.

http://en.wikipedia.org/wiki/Gamma_Knife#Gamma_Knife

but I would imagine the OP already looked at the Wiki page on Gamma Knife. Right?

By the way, the Wiki on Gamma Knife is very 'optimistic'. It certainly has clinical uses, but even back in 2000, my investigation of the research into acoustic neuromas (I had good motivation to learn) showed that the outcomes for treatment of acoustic neuroma using Gamma Knife were not very good. Many side effects and collateral damage to nearby tissues causing facial palsy and other issues. The outcome of Gamma Knife was similar to micro-surgical removal in terms of patient satisfaction.

In Feb 2001, I had fractionated stereotactic radiosurgery at Johns Hopkins for my acoustic neuroma and I have been very happy with the outcome. My hearing in the left ear was toast (an annoyance to be sure), but I never had any problems with my facial nerves which can present significant social impacts as well as problems with the functioning of the eyelids and other issues.

This is my tumor 7 years after treatment. (Circled in the image)

No change in size and the image with contrast agent gadolinium on the right shows darkening of the tumor tissues indicating necrosis of the tumor.

Other than total hearing loss in the left ear (noisy parties or restaurants are no fun) I lead a normal life. No problems with vertigo or balance. I ride motorcycles on the street and trail, ski, water ski, and all those kinds of things.

Getting outpatient treatments (five visits being zapped) at the oncology center at Johns Hopkins made me realize how lucky I was to have such a minor problem. To this day, I still tear up when I think about the bald children on gurneys I saw there.

A couple of questions to your long question:

--What causes the limit on the size treated? Is it the beam size or the focus ability of the equipment. Maybe passing thru tissue makes the beam waver?

--What about beam scatter as it impacts other atoms in its path? I'm guessing (I'm no doctor!) that the beam will spread a bit no matter how well collimated. There would also be attenuation of the beam strength.