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First Images of a Heart Injected With Liquid Metal
KentuckyFC writes "The early symptoms of many diseases show up first in the smallest blood vessels, but imaging the fine structure of these vessels is a tricky problem for medics. The most common way is to inject them with a contrast agent and use x-ray tomography to create a 3D image of their structure. This shows problems in the large vessels but not smaller ones. The problem is the lack of contrast. Conventional contrast agents are based on iodine, which has a high electron density and so better absorbs x-rays than other atoms. But a better solution would be to use a higher density fluid, such as a liquid metal. The obvious fears associated with toxicity and so forth mean this has never been tried. Until now. A team of Chinese biomedical engineers have created the world's first images of a pig's heart injected with gallium. This has a melting point of 29 degrees C, so it's a liquid at body temperature. And the results show the detailed structure of the tiniest blood vessels, revealing capillaries just 0.07 mm in diameter. That's significantly more detailed than is possible with iodine-based contrast agents. An important question is whether this technique will ever be possible in humans. The Chinese team seems optimistic. They say gallium is chemically inert, non-toxic to humans and can be injected and sucked out without leaving a residue. 'It suggests the possibility for localized in vivo vascular-enhanced radiological imaging in the near future.'"
"what could possibly go wrong" post
or the "not invented here" post.
I am intrigued. I mean is this the start of the T-1000???
have you seen my sig? there are many others like it but none that are the same
I think at that point you turn into Wolverine.
At least according to http://theodoregray.com/periodictable/Elements/031/index.s7.html gallium and at least some of its alloys are really sticky, leaving residue on most anything. "Unfortunately, it stains your hands and is hard to get off, so I don't recommend it. In fact, it stains or sticks to just about anything, which is very irritating because it would otherwise make a very nice substitute for mercury where a liquid metal is called for."
I've used one of those gallium-containing fake-mercury thermometers myself, and after a few uses the liquid metal got stuck to the glass tube, and it never worked again. They could have made some better alloy of it or something, but that's not mentioned in the abstract, at least.
(Also, someone is actually using Medium? Impressive, I was compelled to use it for a course, and it was the most dead "social network" I've ever seen.)
I want to see more about the pig on whom the experiment was done.
Having worked with gallium, it is not the easiest metal to work with. It forms oxides easily on its surface, and when these oxides combine with the metal, the metal can stick to metals and glass quite easily. Gallium has been used to back mirrors for that reason.
For those wondering, just because it melts easily, does not mean it has any vapors. Unlike mercury, it has a very high boiling points and has essentially zero vapor pressure at temperatures that can be tolerated by people. As for non-toxic, as far as I know it is not poisonous in reasonable quantities, but neither is it generally recognized as safe (GRAS). Six-nines gallium is probably what to use (99.9999%), as Five-nines gallium (99.999%) usually has signifcant mercury levels in the remaining portion.
It supercools very nicely in plastic containers, and once melted will stay liquid at room temperature for quite a while. It expands upon freezing, like water, and often develops a distinctive cracking pattern when solidifying.
It will eat aluminum instantly. Certain stainless steels are fine for a while, but iron (not plain steel), berylium, tungsten and the like are other metals you can use with it and not have problems with dissolving part of it.
It is a blast, and you can buy small quantities of it from Amazon.
Sure enough
Trust the Canadian government to have a web page devoted to how not to freeze to death.
XML is a known as a key material required to create SMD: Software of Mass Destruction
So my mother was an X-Ray technition for 25 years, and was trained in the 70s. In fact, metals, if not this kind of "liquid metal" have not only been tried, but used. In fact, when she was working back in the 90s, she used to say that soft tissue x-rays back in the 50s were much sharper because of the better contrast they had.
Better....because it contained thorium. While it made amazing x-rays, it turned out to not be so good for the patients. Turns out those "harmless" alpha decays are a lot less harmless when they happen inside your body.
I never really looked up the specific contrast before, apparently mom got her decades wrong, but it was history for her too so that isn't too surprizing: http://en.wikipedia.org/wiki/Thorotrast
"I opened my eyes, and everything went dark again"
1) Absorption of the xray beam is not just based on a material's electron density. The contrast media we use today have a k-shell energy in the mid 30 kev which causes a sharp increase in the amount of absorption due to the photoelectric effect proportional to compton scatter. This means they have a higher absorption at these energies than their atomic number would indicate. Gallium's atomic number is lower than iodine's and its k edge is at 10 kev rather than in the 30s. I find it hard to believe that it provides better contrast resolution AT SIMILAR DOSES than iodine based contrast media. The actual paper (http://arxiv.org/ftp/arxiv/papers/1311/1311.6717.pdf) does not discuss the dose of gallium administered but based on the images I would assume they completely filled the coronary vasculature with gallium. This would not be compatible with life.
2) We have administered gallium 67 salts intravenously for medical imaging for decades, although it is out favor these days due to relative inferiority to newer imaging agents such as FDG-F18. Since the isotope is emitting photons out of the patient rather than us shooting photons into the patient and depending on gallium to absorb them, the doses are much lower for the type of imaging currently used than they would have to be for the proposed use as a contrast agent. As described above, completely replacing the blood with gallium to perform conventional or CT angiography would not be compatible with life.
Source: Radiology Society of North America physics modules http://www.rsna.org/RSNA/AAPM_Online_Physics_Modules_.aspx (massive paywall)
They say gallium is chemically inert, non-toxic to humans and can be injected and sucked out without leaving a residue.
Doing even the most cursory of searches on gallium and reading through the Wikipedia entry (http://en.wikipedia.org/wiki/Gallium) would suggest that gallium is not chemically intert, may not be non-toxic to humans, and given that extremities can easily get cold enough to drop below the freezing point of gallium, I'd have to say that it might rather well leave a residue, forget about the stickiness others have reported.
Yea, that'd be great: inject liquid metal, have it thicken and solidify in your feet and fingertips because you step outside on a brisk day, giving you the equivalent of massive frostbite. No thank you.
There are growing numbers of Chinese researchers in my field (neuroscience) and their results always need to be taken with an extra-large grain of salt. It looks like the same is true here.
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
That's an unusual choice.I would have used Mercury, or hot molten lead.
How do they suck the waste out of the blood of someone with kidney failure? It's a solved problem. Why is slashdot filled with people who publicly announce; "I'm too stupid to solve this problem, so that's proof it's impossible" (or phrase questions with that implication, even if they immediately assert it was "just an innocent question".
Why is slashdot filled with people who publicly claim that the solution to complex problems is already solved because there are solutions to other problems that seem similar on the surface?
Dialysis is not "sucking it out" - Dialysis is carefully filtering it out -- which seems at odds with TFA's assertion that the gallium can be easily sucked back out.
Though the question was about imaging only, so removing it wouldn't be an issue. You don't, the pig dies, you get more gallium and sell some bacon.
Removing it is not an issue as long as you don't care about the creature that you're imaging surviving, which is usually not the case in diagnostic imaging. TFA suggests that it could be expanded to humans.
I'm relatively new to the cath lab, but Iodine-containing agents typically get the job done as far as diagnosing coronary blockages. In my lab, we do nuclear scan for evaluating perfusion even before we decide to do an angiogram (albeit we sometimes do it anyway, but that becomes an insurance battle). A worthwhile advantage would be lower risk of renal failure (not mentioned in the article). While few patients with healthy or even mediocre kidneys end up having problems, it's always a concern with those of less renal function and will sometimes mean not doing an elective cath.
Chewbacon
The Bible is like Wikipedia: written by a bunch of people and verifiable by questionable sources.