

First Images of a Heart Injected with Liquid Metal - mwc
https://medium.com/the-physics-arxiv-blog/first-images-of-a-heart-injected-with-liquid-metal-8b41e1d318c6

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gjmulhol
I've worked a lot with liquid gallium (in semiconductors, not medicine) and it
is pretty nasty stuff. It might not be very reactive, but it is extremely
corrosive to other metals and can crystallize very quickly if given a seed.

A quick search for a gallium MSDS confirms that it isn't exactly regarded as
medically safe right now:
[https://www.rotometals.com/v/vspfiles/downloadables/MSDS_GAL...](https://www.rotometals.com/v/vspfiles/downloadables/MSDS_GALLIUM.pdf)

~~~
bane
It appears to mimic iron(III) in biology which would be all kinds of concern
about what it's doing to red blood cells.

People used to play around with Mercury and even ingest it since it's not
supposed to be reactive. Turns out it's stupidly toxic but nobody figured that
out until recently.

~~~
nmjohn
> People used to play around with Mercury and even ingest it since it's not
> supposed to be reactive. Turns out it's stupidly toxic but nobody figured
> that out until recently.

Well that's only partially true. The toxicity of mercury was speculated as
early as the late 1600s [0]. Then in the 1920s Alfred Stock was doing "modern"
research on its effects [1]. So sure, people played around with it, but it's
toxicity was figured out a long time ago.

Hopefully we've also advanced as a society since then in that we wouldn't
handle something so carelessly - however it would be a little naive to
actually believe that, I'm sure 100 years from now our descendants will look
back and judge us just as we do.

> Qian and co are optimistic. They point out that gallium is chemically inert
> and believed to be non-toxic in humans. And they say a small amount of the
> metal can be injected into the target vessels and sucked out afterwards
> without leaving a residue.

[0]:
[https://en.wikipedia.org/wiki/Johann_Jakob_Wepfer](https://en.wikipedia.org/wiki/Johann_Jakob_Wepfer)

[1]:
[https://en.wikipedia.org/wiki/Alfred_Stock](https://en.wikipedia.org/wiki/Alfred_Stock)

------
graeham
Bioengineering researcher here, who works mostly on analysis of vascular
imaging.

Imaging in general is a field in medicine of increasingly growing importance -
and as the article suggests its increasingly limited by resolution of the
images. I personally see patient-specific diagnostics from image processing to
be one of the most promising medical advances to expect in the coming decades.
Image resolution is a major thing holding this back, it probably needs to
improve ~2-5X for many applications.

This kind of thing is exciting, but probably at least a decade from clinical
use, if at all from this particular technique. Use in research is itself quite
interesting in at, at least to my knowledge, microvessels can only be observed
by micro-dissection, which disturbs the tissue.

Being able to better observe microvessels clinically could have pretty big
implications for heart attacks, strokes, cancers, and kidney functions.

The experiment (from the paper) was done on a in vitro (removed) pig heart
(and kidneys, reported in the paper but not Medium article). In vitro studies
often give much better images than in vivo because there is less

I am sceptical of the ability to retrieve the injected gallium, although I am
not terribly familiar with its properties. I believe it is a quite rare and
expensive metal, and the volumes needed for this would be small but not
insignificant (maybe 20mL/ organ imaged?). I could see retrieving it being an
issue, and particularly in the heart or brain, blood flow would need to be
restored within a few minutes.

Iodine contrast agent, which this technique is compared against, is pretty
nasty stuff. It gets filtered out by the kidneys, and is toxic to them. If
anything, there is a movement to get away from contrast-based CT imaging of
vessels and towards MRI or ultrasound, where contrast isn't required.

~~~
lostlogin
Radiographer here. MRI uses contrast about as much as CT and gadolinium
toxicity turns out to be at least as bad (which took a while to work out due
to the slow onset of symptoms). While our non contrast techniques are good and
are getting better fast, nothing beats a good contrast run. However MR of
coronary arteries isn't anywhere near as good as CT or cath lab imaging which
is high quality. It is notable how poor the quality of that pig heart image
with iodine based contrast is. It is laughable. A quick google of CT or
cathlab angiography images will show examples vastly superior that were
obtained on beating hearts in live patients - rather more difficult than
direct injection into a dead, removed heart.

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elwell
On a related note, look at what gallium does to aluminium:
[http://youtu.be/9DEjE8jiwT8?t=1m7s](http://youtu.be/9DEjE8jiwT8?t=1m7s)

~~~
ubernostrum
To be fair, lots of things will do that, since aluminum is an incredibly
reactive element. Once you scratch away/through the oxide layer that normally
protects it, you can get all sorts of stuff to react with it.

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burke
Somewhat higher resolution image on page 8 of
[http://arxiv.org/pdf/1311.6717v1.pdf](http://arxiv.org/pdf/1311.6717v1.pdf)

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mrfusion
Speaking of filling organs with metal, I've read that the lungs have an
absolutely amazing amount of surface area. So I got to wondering if we could
somehow use a lung (say removed from a pig) as a super capacitor?

Maybe use a non conductive material to thinly coat the inside of the lung and
then fill it with metal?

~~~
_archon_
Or do that, then burn away the flesh and use it as a heat exchanger.

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Cthulhu_
I'd be very reluctant to have gallium injected in me, but it's still a
valuable technique to map out (and make casts of) hearts and vascular systems
in animals or people that donate their body to science.

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madaxe_again
Neat, but unless this is in vivo, this isn't all that thrilling, as we've been
doing this sort of thing with wax and plastic for more than a century.
[http://cruciblezine.files.wordpress.com/2010/06/circulatory-...](http://cruciblezine.files.wordpress.com/2010/06/circulatory-
network-0101.jpg)

~~~
twic
Some guy does it with aluminium and ants' nests:
[https://www.youtube.com/watch?v=IGJ2jMZ-
gaI](https://www.youtube.com/watch?v=IGJ2jMZ-gaI)

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MichaelApproved
_And they say a small amount of the metal can be injected into the target
vessels and sucked out afterwards without leaving a residue. "_

The most curious part of the story isn't there, how do you suck out the metal
afterwards? What percentage are you able to reliably _suck out_?

~~~
ygra
»Without residue« sounds like 100 % to me.

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disputin
Needing some education here. They took a pig's heart, dead, injected it with
metal, and are impressed that this showed up in an x-ray? Gunther von Hagen
with metal?

