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#280229 - 09/02/08 07:58 PM
Re: Inoperable Malignant Brain Tumors
[Re: Elena]
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experienced member
Registered: 02/17/08
Loc: WA, USA
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Laser is a enigmatic thing. Recently I read that method to cure some kinds of cancer is developed. They used laser, but don't know how it works. There are some chemical dyes that, when injected into the blood stream, are attracted to cancerous tissue. Lasers are single wavelength devices and only burn surfaces that absorb at that wavelength. The appropriate laser beam can pass through tissue without much damage until the very narrow beam reaches the cancer, where the light is then absorbed; cauterizing it. Obviously there is heat transferred to the surrounding tissue, but a pulsed laser is used that has extremely high power, but a very short pulse length (milli/micro/even femto-seconds long pulses can be achieved) so that the heat from the cancer doesn't spread very far. Lasers may be enigmatic, but processes using lasers are fairly straight forward. That same characterisic of selective absorbtion can be used in a lot of ways. For instance if you paint an object (say an airplane) with different color coats of paint you can "paint" it with a computer controlled laser so that the lower layers are sequentially exposed without damaging the aluminum skin. This is much cheaper than making masks and manually applying paint. More accurate, too. I could go on boring people for a long time with different laser uses: I used to administer a laser lab.
_________________________
Bad Bird
A rising tide sinks all leaky boats. (Paraphrased view of an economic theory, by me.)
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#280506 - 09/05/08 03:38 AM
Re: Inoperable Malignant Brain Tumors
[Re: Bad Bird]
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Administrator
Registered: 09/01/97
Loc: CT, US
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"Gamma Knife" is a marketing phrase, no actual knife-cutting is involved. It is actually focused radiation treatment on tumors or other unhealthy tissue within the brain that makes it possible to deliver extremely high does of radiation to focii deep within brain tissue that would be destroyed by conventional surgery when accessed with scalpels. The gamma radiation kills the tissue it is aimed at with very little damage to surrounding brain tissue. Scalpel surgey, in comparison, wrecks ruin and havoc on healthy grey and white matter no matter how skilled the neurosurgeon is, as he cuts a path through healthy tissue to the place where the bad gunk needs to be excised, it's unavoidable.
Gamma radiation is focused on various locations within and surrounding the area of the malignancy, and the patient (who is usually awake for the painless procedure) is strapped and immobilized on a table which is electronically moved beneath the gamma beam. Destruction of healthy tissues is kept to a minimum this way, although there is some resultant swelling and inflamation following the procedure, as one might expect from radiological burning. After the procedure, the patient walks out, no hospitalization required.
This type of bloodless surgery has had, in certian types of conditions and cancers, high rates of success, but not every condition lends itself to this treatment. Epileptics are another class of sufferers who have found gamma knife surery a terrific boon, it isn't only for tumors.
I don't know too much about this new laser surgery yet, but I'm interested in finding out more.
_________________________
Helice
Nemo me impune lacesset. ~~~~~~~~~~~~~~~~
The surest way to corrupt a youth is to instruct him to hold in higher esteem those who think alike than those who think differently.
--Friedrich Nietzsche
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#280593 - 09/05/08 05:42 PM
Re: Inoperable Malignant Brain Tumors
[Re: Helice]
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experienced member
Registered: 02/17/08
Loc: WA, USA
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Gamma radiation is focused on various locations within and surrounding the area of the malignancy, and the patient (who is usually awake for the painless procedure) is strapped and immobilized on a table which is electronically moved beneath the gamma beam. Destruction of healthy tissues is kept to a minimum this way, although there is some resultant swelling and inflamation
I don't know too much about this new laser surgery yet, but I'm interested in finding out more. Gamma and laser surgery are really quite similar as they both use radiation focused on the cancer. As understand it, the laser surgery is more narrowly focused (both in beam size and in heating effects on surrounding tissue). The gamma surgery, however, is totally non-invasive, while the laser surgery involves positioning a very fine fiber-optic cable right at the cancer. Both use the same technology of CAT-scans and MRIs with external positioning "cages" to know exactly where the cancer is. (Similar to what has been discussed in the "Essential Tremor" thread.) The Gamma Knife technique requires repeatedly 'zapping' the tumor from many directions so that the tissue killed is the tissue that has received the most radiation; the focal point. To do this the patient is repeatedly repositioned under computer control. In the Laser technique, the fiber optic cable is inserted through a small hole in the skull until the end is right at the tumor, which has been dyed (via the bloodstream) with a chemical that is attracted to cancer and reactive to the laser wavelength used. In my layman's opinion: I would go with the laser process because it sounds like it is much more focused. Positioning errors and beam dispersion could mean more adjacent tissue damage from the gamma knife process. The laser positioning process is becoming quite common and physically correct positioning can be verified once, whereas the gamma knife beam accuracy not only cannot be positively verified, but it must be verified for each position. AGAIN: I'm not a doctor and should you have a brain tumor SEE YOUR DOCTOR AND DISREGARD ANYTHING THAT I MAY HAVE SAID! One source of additional information is: http://tinyurl.com/6zvqa3
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Bad Bird
A rising tide sinks all leaky boats. (Paraphrased view of an economic theory, by me.)
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