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.'"

Comments

I'm waiting for the

[etash]

"what could possibly go wrong" post

or the "not invented here" post.

Re:I'm waiting for the

[Phics]

They have a term in medicine called "contraindication". Basically, when there are contraindications, (downsides), the risks and benefits of a treatment are weighed, and if the benefits outweigh the potential complications, it might be worth trying regardless. Test subjects sign on for trials because they feel the risks are acceptable. The AC may not fall into this category, but that doesn't mean (s)he's wrong if they don't choose to 'sign up' to have this done unnecessarily. I wonder if you'd have had a similar reaction if someone suggested injecting a fungus into the bloodstream... sounds horrifying, but how many lives has penicillin saved?

Re:But what if

[XMark3]

I think at that point you turn into Wolverine.

Gallium = Sticky

[Iskender]

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.)

Re:Gallium = Sticky

[ridgecritter]

It is that. I've seen it stick to Teflon and graphite components. It coats glass and silicon wafers with a nice mirror surface.

Lowest melting nontoxic liquid metal I've heard of is Galinstan, a eutectic alloy of gallium, indium, and tin, melts around -19C. http://en.wikipedia.org/wiki/Galinstan

Gallium Metal

[Artagel]

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.

Re:But what if

[H0p313ss]

Sure enough

Trust the Canadian government to have a web page devoted to how not to freeze to death.

Re:The pig

[rwise2112]

Here it is.

Never been tried?

[TheCarp]

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.

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