Slashdot Mirror
Anti-Matter's Potential in Treating Cancer
eldavojohn writes "The BBC is taking a look at how atomic physicists are developing cancer treatments. A step past radiotherapy, the CERN institute is publishing interesting results: 'Cancer cells were successfully targeted with anti-matter subatomic particles, causing intense biological damage leading to cell death.' The press release from last year is finally sparking interest in the medical community."
Thats kind of the purpose of the article, if you read it. They compare using charged particle beams to traditional radiotherapy treatment and comment that using particle beams allows the raditation to be better focused on the tumour (in this case a spinal tumour), leading to less death of surrounding tissue.
A complete set of mirror image subatomic particles. The antimatter analogue to the electron is the positron, etc.
No you can't hold it. It annihilates matter when it comes into contact with it, releasing a burst of energy.
Theoretically the Big Bang created equal amounts of matter and antimatter, but we're wondering where the antimatter is...maybe whole galaxies are composed of it? There's no way to tell from the light - photons are the same whether generated by matter or antimatter.
Short of that, small amounts are created in particle accelerators and in the upper atmosphere, I believe.
As usual, Wikipedia is helpful.
HBI's Law: Frequency of calling others Nazis is directly correlated with the likelihood of the accuser being Communist.
Antimatter is... just as it sounds. The opposite of matter.
"Matter" in ordinary parlance has various important properties: solidity, resistance to motion (otherwise known as mass) and so on.
Anti-matter has every single one of these properties, so it is not particularly helpful to say it is "the opposite of matter" because it is not.
Anti-matter is simply matter that consists of anti-particles, as correctly indicated by the article you link. Anti-particles are just like ordinary particles except that they have the opposite charge, parity or magnetic moment (in the case of neutrons). This minor change results in a fairly large cross-section for mutual annihilation when an anti-particle scatters off of its corresponding particle.
Blasphemy is a human right. Blasphemophobia kills.
Wrong.
No, that's what he said.
Your failure to grasp his words does not invalidate them, it merely illuminates your own poor understanding of the topic.
Let's put it another way: if there was an anti-sun with an anti-solar system, exactly like Earth but with every particle the inverse of our Earth, they would be exactly the same. (Even when they eventually met and obliterated each other -- matter blows up antimatter just as well as antimatter blows up matter.)
What we get then is actually a great example of an "exotic atom" - the two mirror particles form an unstable "atom" called positronium which is extremely short-lived and which decays into two photons going at 180 degrees to each other. This is important because that is the only way you can detect such an annihilation taking place. At any rate, my point is that this is hardly a "high-energy" application as so many science hacks have sneeringly pointed out here so far. Radiology is an established field of medicine and one reason it is so is because radioisotopes can be made so damn selective (tracers anyone? :P).
In PET you don't inject positrons. It's positron EMISSION tomography. You inject a substance that, when it decays, emits positrons, then they quickly run into an electron and annihilate, producing two gamma rays, which you detect.
These story is about using anti-protons (very different than positrons) and they're using a beam (well, more than one beam for an actual treatment) of reasonably slow ones. As stated in the article, there are really only a couple of places in the world that can produce such a beam and the equipment to do it is very large.
In contrast, for PET you just need a cyclotron (costs a few million) to make the radio pharmaceuticals for you. My hospital is installing one. But they're not going to be making anti-proton beams any time soon.
First off, heavy ion beams make sense as a way of treating cancer. The reason is that when a heavy ion passes through matter, it decelerates along a straight-line path, and deposits a very large percentage of its energy near the very end of its path. If you compare with x-rays as a radiation treatment, x-rays deposit energy in an exponential-decay pattern, so if you're treating a brain tumor with a pencil beam of x-rays, the tissue that gets hit with the most radiation is the skin, followed by the skull, followed by the good parts of the brain, followed by the tumor. Now in reality you don't use a pencil beam, you use a focused beam, so it's not quite that bad, but focusing also works with heavy ion beams (I believe you actually rotate the patient, not the beam). So with heavy ion beams, you get energy concentrated near the tumor for two different reasons: (a) focusing, and (b) the pattern of energy loss, which is peaked at the end of the trajectory.
OK, now about antimatter. An amazing number of posters apparently (a) haven't read the article, (b) haven't understood the article, or (c) don't know enough physics to make heads or tails of any of this.
Find free books.
gamma knife= bad at best, horrible in practice. There IS NO SAFE LEVEL FOR IONIZING RADIATION. Splitting it in 8 beams only increases the amount of affected tissue. The only reason its in use is that its marginally better than dying.
Bragg-peak of decellerating particles== huge dosage in a very tiny volume, relatively little interaction of the particles during the inition part of ther journey through the body.
And, as i post this right now from beamline 8.0 of the Advanced Light Source in berkeley, i can tell you that biological molecules have nice brought absorption spectra, and while there might by sharp pi-resonances, those are smeared out a lot in liquid solutions (plus, the carbon edge is really crowded, there is no empty space to "design a molecule" to.
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
Get a copy of Prof Hawkins' "A brief History of Time". He explains it all really well and there is only one formula in the book.
Excuse me, but please get off my Pennisetum Clandestinum, eh!
If it were simply a matter of "aim a particle beam" while adjusting other properties, it would have been done decades ago. Current non-anti-matter-particle beams or EM radiation are more than potent to kill cancer cells. Unfortunately it is equally deadly to normal tissues, which restricts it's current use. Radiotherapy in various forms has been around for ages and is effective, but is limited because of it's non-specificity.
How then is "anti-matter" any better? and to my knowledge, PET is a diagnostic test, not a therapeutic intervention (yes, i AM a doctor).
gamma knife= bad at best, horrible in practice. There IS NO SAFE LEVEL FOR IONIZING RADIATION. Splitting it in 8 beams only increases the amount of affected tissue. The only reason its in use is that its marginally better than dying.
As someone whose wife went under the gamma knife, I have to tell you that you are full of shit...at best. She went under in the morning to zap a brain tumor and I took her home that afternoon (or was it the next morning?--I forget which). The tumor was completely destroyed and she suffered no ill-effects whatsoever. Major brain surgery, one day in the hospital, no cutting, no side-effects. Yeah, that was pretty horrible.
I live ze unknown. I love ze unknown. I am ze unknown.