Hospitals Look to a Nuclear Tool to Fight Cancer

The feed points us to a NYTimes article about hospitals using particle accelerators to treat cancer. While expensive, proponents say that the proton beams generated by the accelerators are more precise than conventional X-ray radiation therapy. This results in fewer side effects and reduced irradiation of surrounding tissue. The technology's critics say that the cost is not justified by a measurable increase in the level of care given to the patients. Nevertheless, this is an excellent example of "pure scientific research" leading to a useful, unrelated technique. From the NYTimes: "Tumors in or near the eye, for instance, can be eradicated by protons without destroying vision or irradiating the brain. Protons are also valuable for treating tumors in brains, necks and spines, and tumors in children, who are especially sensitive to the side effects of radiation."

Comments

Proton packs

[Rob T Firefly]

As another unrelated side benefit, you can strap it to your back and use it to catch ghosts.

Re:Side Effects?

[vjmurphy]

Focused protons would likely give you better superpowers, too. I mean, we all know what gamma rays do, and I, for one, don't want to prance around with green skin and purple short shorts when I'm angry.

Re:Side Effects?

[ZombieWomble]

Based on a couple of assumptions*, the entire reason for making use of this therapy is to mitigate the side effects of traditional radiotherapy. In traditional x-ray based therapies, the energy from the beam is deposited nearly continuously along the beam length, giving a roughly exponential falloff (I say nearly, as there is an initial buildup at the surface as secondary particle counts build up, and it is from the peak slightly below the surface that the exponential falloff begins).

By contrast, accelerated protons deposit their energy almost evenly, at a relatively low rate, until they are slowed to a certain energy, at which point their deceleration rapidly increases, accompanied by a massive increase in linear energy deposition. This leads to the "Bragg Peak", which offers a much, much more accurately targeted beam than is possible with conventional sources. (See this illustration as an example - compare the red line (in this case, C12 ions, but a similar principle) to the green line (an 18MeV photon beam). By carefully tuning the beam energy and orientation this point can be scanned over the tumour volume, giving a very localised dose deposition.

What puzzles me is why this is news - I was under the impression that this concept is well-established, and has been fairly well verified already. Just some fluff to fill up the science and medicine section, maybe? Now if it was about the CERN anti-proton tests, that's certainly something with a more dubious cost/benefit analysis...

* - I say a few assumptions, these are basically the principle ones behind all radiotherapy - that is, that all dose at the end of track structures is created equal and all dose is bad according to the LNT. While these ideas may not be strictly true, it is unlikely for them to be so wrong that it would invalidate the treatment as a whole.

Re:Side Effects?

[johnny maxwell]

Since they are accelerated, I'm guessing they penetrate further, but they will be stopped quicker too (charge, mass, volume, all these will make them easier to stop than high energy photon radiation). Best of all, it's the stopping/slowing of the protons that kills the cells (they hit stuff, break stuff, and stop/slow down), so less energy will be needed since the majority of the high-energy photons would just pass through. The trickiest part would be to determine how many protons and with how much energy.

For a nice picture of energy deposition vs. depth see e.g. http://www.gsi.de/forschung/bio/energy_e.html
One can adjust the peak energy deposition's depth by varying the proton's energy. The surrounding tissue gets a much lower dose than in X-Ray irradiations.
Combine the particle accelerator with a PET (http://en.wikipedia.org/wiki/Positron_emission_tomography) and you can irradiate a cancer with cubic millimeter resolution.

This is actually not a new, purely academic technique, it is already commercially available, see http://en.wikipedia.org/wiki/Proton_therapy

Attention: I'm not a doctor but a physics student :)

As the husband of a survivor...

[_14k4]

Personally, who cares how expensive it is. I mean, we're not rich people and we are pretty close to that sarcastic "upper lower middle class" line.. but watching my wife go through chemo and surgery (no radiation, thank God) hurt me more than I can ever explain. If there was a way to make sure that radiation was a little "cleaner" and crisp around the edges, I'd say go for it. Chemo and surgery are hell enough.

Plus, x-rays are so last century. Everyone knows the new thing is protons.

Re:As the husband of a survivor...

[Rich0]

Personally, who cares how expensive it is.

The person paying for it. In the US that would probably be an insurance carrier (those who pay a higher premium might get access to it). In most of the rest of the world it would be your government (if you are lucky you might get access to it).

I have only sympathy with what you went though - I've had someone close to me go through life-threatening medical problems as well. I'm all for improving the level of technology available. However, economics always comes into play - it just isn't politically-correct to admit it.

No nation on earth fully meets their medical needs financially - everybody rations care at some level. Every nation also faces questions like "is it better to spend $500M on one machine in one hospital that will cure 10 extra people per year, or $500M on something else that might save more lives?". The cost of one of those machines would also pay for a lot of doctors and nurses as well - you might save more lives just by giving patients more time with caregivers.

The problem in medicine is that nobody is allowed to discuss the hard questions like this without being branded as insensitive or inhuman. The problem is that the hard decisions get made one way or another, and without genuine debate the decisions are probably made in a less-than-ideal way. Money spent on particle accelerators saves lives - but so does money for food/education/sanitation/law-enforcement/doctors/clean-air/etc. There is only so much money to go around - and economics are all about spending it where it will do the most good...

Re:critics... let me guess

[arivanov]

Aaa... The so called ~NHS logic. Treat 10 times more people regardless of the fact that the result is nil, but do not use the treatment that may actually save one of the 10 because it is expensive.

They do it for everything.

They consider it OK to treat Eczema by splating children with a bucket of hydrocortisone twice a day and drowning them in Claritine despite the fact that the result is nil and the treatment drags on for decades. After all it is cheaper per-day and per-dose than Pimercrolimus or Advantan. They miss a crucial difference - the latter can actually put eczema under control and reduce it to a point where treatment is unnecessary most of the time.

Same for allergies - there is practically no way in hell to get them to approve gammaglobulinisation therapy.

Same for vaccines - they use "all animals are equal, but some are more equal than the others

approach and vaccinate themselves against chickenpox and leave children who are in high risk groups like astma and eczema sufferers to fend for themselves (and die from secondary infections). After all, vaccination is expensive, isn't it.

Same for cancer. Treat 10 people without any one of them getting improved survival rates as long as "it improves their quality of life", but do not use treatment that will actually give one of out 10 a chance to survive because it is expensive. Do not pay for herceptine because it is expensive, use cheap stuff regardless of the fact that as a result UK has cancer survival rates of a 3rd world country (worse than the whole of the EU).

And so on.

Sorry. NHS treatment selection logic is flawed by design. It is based on fake happy commie concepts of fairness which are misplaced here. The main goal of medicine is to try to cure the patient. If you have the choice of using a medication that has a chance of curing even one more patient and medication that will cure even one less the "cost" option is simply no longer part of the equation. It is there only if the treatments are equivalent.