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Music
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Herald Angel: And now we come to the talk[br]entitled low-cost non-invasive biomedical
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imaging. Current medical imaging has[br]problems: it is expensive, it is large,
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rarely preventively used and maybe you've[br]heard of the story of a fMRI - this is the
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magnet resonance tomography - they put in[br]a dead Salmon and they can get a signal
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from brain activity from it. There's also[br]lots of problems in the software as well.
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A little story, maybe you look it up. And[br]how this whole mess can be solved with the
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technique called Open Electrical Impedance[br]Tomography - this will tell us Jean
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Rintoul. Give a big round of applause for[br]Jean.
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applause[br]Jean Rintoul: Thank you.
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Hello everyone. Today I
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will be talking about an open source route[br]for biomedical imaging using a technique
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that's in R&D called Electrical Impedance[br]Tomography. Not many people have heard of
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it, which is why it seems like it's[br]important to mention. First of all, I'll
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just give you the vision of what it would[br]be like if everybody had access to cheap
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biomedical imaging. Right now you only get[br]imaged when something's gone wrong. And,
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moreover, you only actually get to use[br]these tools when something has gone wrong
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in a first world country when you're lucky[br]enough to be close to a hospital and have
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access to these technologies. That's a[br]very limited number of people. What's even
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worse about it: is it's hard to hack! So,[br]if you wanted to improve this technology
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yourself - medical physics is an amazing[br]field - but it would be very hard to do so
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because you don't have a three million[br]dollar MRI scanner sitting in your garage.
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Maybe you do, that's good for you, just[br]not many of us do. If we did have cheap
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biomedical imaging we could do things like[br]do preventive scans so you would wake up
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in the morning you'd like, take a shower,[br]the device would be quietly imaging your
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body, would warn you if the slightest[br]little thing when went wrong. You'd do
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machine learning over it, it'd be[br]wonderful wonderful for health care. So,
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that's the vision of what biomedical[br]imaging could be. And the other point is
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sometimes we move forward faster when we[br]share the information. I worked in defense
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for a brief period and people didn't[br]really share information between each
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other, and I think that inhibited science[br]from moving forward. So, sharing is
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caring.[br]So today I'm going to go through a few
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different things. I'm going to go through[br]the current biomedical imaging
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technologies. I'll give you an[br]introduction to Electrical Impedance
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Tomography. I'll go through the open[br]source Electrical Impedance Tomography
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Project. Then I'll go through some[br]applications that we could apply it to.
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And then I'll suggest a few different next[br]steps that we can go into because by no
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means is it finished. Right now we have[br]four different main existing imaging
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modalities. Your MRI scanner, which is a[br]wonderful tool, it's huge, very expensive.
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The most commonly used imaging is actually[br]CAT scanner which sends our x-rays through
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your body which is ionizing radiation,[br]which is bad for you because it causes
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cancer in the long run if you get too many[br]of those scans and it's actually the first
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first scan that you'll get when you go[br]into the emergency room. It's the most
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commonly used. And as we all know we've[br]got those grainy images that come from the
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ultrasound of fetuses, wonderful tool[br]except for the scattering due to the sound
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gets scattered when you have different[br]density materials next to each other. And
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not exactly an imaging modality but a very[br]important diagnostic technique is EEG.
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So you might ask, how do we classify these[br]right now? we have 3 main types of
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resolution. Spatial, contrast, and time.[br]Spatial resolution is, basically, what
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space you can determine 2 different[br]objects from each other. Contrast
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resolution is soft tissue or subtle[br]differences in tissues. And time
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resolution, as it sounds, is how things[br]change over time and how quickly you can
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do these images together. Your CAT scan,[br]your basic machine in a hospital,
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costs 1 to 2.5 million dollars.[br]You probably didn't get one for Christmas
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to play around with. Oh well. It's also[br]got this ionizing radiation, you've got
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a lot of maintenance, and [br]dedicated technicians.
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An MRI, say, your average 3 Tesla magnet
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with its own helium quenching chamber[br]no less, as well as dedicated technicians
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and experts who can actually read[br]the images. Again $3,000,000. An amazing
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and beautiful technology, but really[br]expensive. Amazing spatial resolution, the
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best. When it does something at this very[br]high spatial resolution, it actually takes
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4 minutes and 16 seconds. Which is a[br]really long time to take to do this
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wonderful spatial resolution image.[br]Ultrasound, it's a bit grainy due to
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scattering. On average it costs about[br]1$115k, not too bad. It's a pretty minimal
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health risk. EEG. EEG doesn't do any image[br]reconstruction. In fact it does very
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little in many ways. But it is still very[br]useful. Your average medical grade by EEG
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system is $40k. You might also know of[br]some open source EEG projects which are
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pretty cool. So just a note on the[br]radiation of CAT-scans. It's actually the
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biggest contributing cause of radiation in[br]the United States. So here I just put
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those biomedical imaging modalities onto a[br]graph so that you can kind of think of
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them in terms of spatial resolution and[br]time resolution, and where they fall in
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the picture of common things that go wrong[br]with people. Like, X-rays or CAT scans are
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great for for looking at bone and bone[br]breaks; pulmonary edema, that's water on
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the lung ,tuberculosis, huge in third-[br]world countries, massive problem. You
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don't actually need super high spatial[br]resolution to be able to detect it. And
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it's important to sort of understand what[br]you can do at different spatial and time
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resolutions. Under like, the optimal goal[br]of all of this, I put non-invasive
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electrophysiology. What that is, is high[br]spatial resolution and high time
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resolution. That's where you can measure[br]ion activation, or basically what cells
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are doing when they communicate with each[br]other, which is right now only done in an
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invasive manner.[br]Today I'm gonna talk about this new
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technique called Electrical Impedance[br]Tomography and describe where it will fit
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in amongst what already exists. So what is[br]it. Okay yeah basically you send AC
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currents through the body, say a 50[br]kilohertz current. And that will take
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different routes based on what tissue[br]there is. So it might go around some cells
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and straight through others. And that's[br]really important because differentiating,
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say, fat from muscle is one thing that you[br]could do. But you can go further and
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differentiate, say, tumors from healthy[br]tissue. Because tumors have different
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impedance spectra to the healthy tissue.[br]So as you can see, that would be very
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useful to do. This set up here is a called[br]a phantom. What it is, it's like a
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simulated human body. You get some[br]saltwater - the body is 80% water as you
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might know -you get some meat or[br]vegetables. You put it inside and then you
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use that to image. So we have current[br]flowing through all these different
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directions and we recreate an image. Right[br]now it's used for lung volume
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measurements. This is a baby with an EIT[br]setup. Muscle and fat mass, there's a
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paper on gestural recognition that just[br]came out this year, you can look at
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bladder and stomach fullness. There's some[br]research papers on breast and kidney
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cancer detection. There's another research[br]paper on hemorrhage detection for stroke.
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You can also look at the ... there's more[br]R&D on the depth of anesthesia in in
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surgery as well, which would be another[br]interesting use for it. So all of these
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are sort of in the works and you might[br]ask, "Great, that sounds amazing, why
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isn't everybody using it already?" Well[br]yeah it's really an R&D technique right
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now and it has a big problem: its spatial[br]resolution seems pretty limited. So it's
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limited by the number of electrodes. But I[br]will discuss some potential ways to get
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around that. As we go, it might not ever[br]get to the spatial resolution of MRI.
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But maybe we don't need it to to be[br]useful. Because it's so compact. It's so
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cheap, nothing about it is expensive. It's[br]got better source localization than EEG.
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It does not ionize,[br]it's not harmful to human tissue. It's
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also got great time resolution, so it has[br]advantages and disadvantages. I'll just
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remind you of what the first MRI scan[br]looked like at this point in time. As you
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can see it looks pretty crappy in 1977.[br]And now it looks pretty awesome. That's a
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slice of my head by the way in a 3 Tesla[br]MRI scanner. This is what early EIT looks
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like. That's with 16 electrodes only. What[br]will it look like in a few years time I
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don't know. I hope that MRI gives you a[br]pathway that it will take take too.
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Now I'll introduce you to the OpenEIT[br]project. The OpenEIT project is obviously
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open source. It has a PCB design done in[br]Eagle CAD. It has firmware written in C.
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It has a Python dashboard that lets you[br]see the reconstruction in real time. It
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also has a reconstruction algorithm which[br]I'll go into. And you can get it from
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github right there. So how does it[br]reconstruct an image? OpenEIT right now
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has 8 electrodes and what you do is, you[br]send this 50 kHz current through every
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combination of those 8 electrodes and you[br]get a different impedance value for each
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of those measurements. On the left you can[br]see basically what you're doing. You know where the
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electrodes are positioned and you get one[br]value going horizontally. You add it to
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another value coming from another[br]direction. And again, you can sort of see
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it's getting a low resolution image as it[br]goes around adding those values together.
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If you use many, many views you bring the[br]image back. This is the radon transform,
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that's what it's called, and you [br]basically just send lots of current
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through these different slightly different[br]angles and you build up something called a
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sinogram which is over there. And then you[br]invert it to get the image back. I used
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OpenCV which is a really common image[br]processing library to do this. You can
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just do it with a regular image yourself[br]and try it out. But what I did is exactly
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the same as what you do with a regular[br]image, except I use current to be the
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input data. So this is the PCB design [br]in Eagle. Basically it has a
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few different features. A connector for[br]your 8 electrodes. It's running an ARM
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Cortex M3, which is quite nice. It has a[br]dedicated DFT engine for doing your direct
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Fourier transform in real, time which is[br]also quite nice. A JTAG debugger to easily
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reprogram it. It's got coin cell or[br]external battery options. It has UART to
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get the serial data off. And you can also[br]flip it to Bluetooth mode and get the data
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off by Bluetooth if you felt like going[br]Wireless.
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At this point you might be asking "Is this[br]safe for me to play around with?", which
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is a really great question because the[br]answer is actually "Yeah! it is". There's
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some guidelines called the IEC60601-1[br]guidelines for safer use in humans. And
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basically which says it should be, and[br]openEIT is less than 10 micro amps which
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is great because that's well within their[br]guidelines. If you want to compare it to
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other things that are completely legal,[br]say I don't know if you've seen there's
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like late-night TV ads for those abs[br]stimulators that stimulate your muscles,
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there are about 15 to 20 milliamps just[br]for reference and as a scale to look at
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the 10 micro amps. So some of you might[br]have used them already and that's hugely
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more current than what we're putting[br]through to image the body here. This is
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what the dashboard looks like. It does the[br]reconstruction. You can connect to serial
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at baseline. You can obviously adjust[br]sliders to look at the area that you want
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to look at. You can read from a file and[br]fiddle around however you would like to.
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This is what it looks like when you[br]reconstruct something. I have a phantom up
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there which is a part of water with a cup[br]in it. I moved the cup around anti-
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clockwise so you can see in each of the[br]pictures I move it around a little bit
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more. And you can see the reconstruction[br]there with me moving the cup around again.
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This might not be wow-ing you with the[br]resolution, with only 8 electrodes. It's a
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proof of concept but that's okay. Let's[br]see if we can make this I make this go.
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Here's a real-time video demonstration of[br]it. Here's me with a shot glass. I'm
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moving around anti-clockwise. Hopefully[br]you can see on the left the image being
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reconstructed in real time. And there we[br]go, move to the bottom. You can see it
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over there and again up to the top. you[br]can see it over there. So that's a basic
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proof of principle version of it running.
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So the first MRI scan of human [br]lungs wasn't that amazing.
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Early EIT scan wasn't either.
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applause[br]Something else that you can use it
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that for is differentiating objects.[br]Multi-frequency. This is what they're
0:16:08.590,0:16:13.969
doing the breast cancer and kidney cancer[br]scans on. Basically you send different
0:16:13.969,0:16:17.920
frequencies through these times, called[br]multi-frequency Electrical Impedance
0:16:17.920,0:16:23.180
Tomography and you build up a spectrum.[br]Here I've got an apple, a pear oh no a
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sweet potato and and some water. And I've[br]sent through these different frequencies
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and I get these different spectrums.[br]They're different, you can see that
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they're different. They're quite obviously[br]different but yeah you can also just
0:16:35.829,0:16:39.680
simply classify. And on the left you can[br]see where the water is, the apple is, the
0:16:39.680,0:16:44.769
sweet potato is. Or, the sweet potato and[br]the apple a little bit harder that one.
0:16:44.769,0:16:53.800
But that's basically what you do when you[br]detect cancer. So that's what I did. But
0:16:53.800,0:16:57.760
maybe we should look at the other papers[br]and see what they did because they did
0:16:57.760,0:17:04.589
better than me. So there's this guy called[br]Aristovich, 2014 he published spatial and
0:17:04.589,0:17:07.569
temporal resolution, and using this[br]technique 200 micro meters less than 2
0:17:07.569,0:17:14.230
milliseconds which covers most of the[br]applications that I listed on that graph
0:17:14.230,0:17:19.260
at the start of the talk. The downside[br]here is that it was an intracranial array,
0:17:19.260,0:17:24.190
so it was under the skull. So very dense[br]electrodes, a lot more electrodes. I only
0:17:24.190,0:17:32.089
used 8 he used like 256 so you can see[br]that it can be, like, the potential is
0:17:32.089,0:17:36.859
there.[br]So how should we use it first? what's a
0:17:36.859,0:17:41.230
nice low hanging through fruit? What about[br]medical imaging in the developing world
0:17:41.230,0:17:46.649
where I believe 4 billion people don't[br]have access to medical imaging. No MRI, no
0:17:46.649,0:17:51.519
CAT scans. Why is the EIT good for that?[br]It's cheap to mass-produce, super
0:17:51.519,0:17:58.089
portable, super low power. So that would[br]be a great place to start. What could we
0:17:58.089,0:18:05.330
do first? I'm going to go back to this[br]image again and have a look. Tuberculosis
0:18:05.330,0:18:09.110
affects a lot of people in the developing[br]world and you don't need amazing spatial
0:18:09.110,0:18:14.901
resolution to detect it. That would be a[br]good one. Or what about a pulmonary edema?
0:18:14.901,0:18:21.660
Pulmonary edema is water on the lung. It's[br]actually already used for that. You can
0:18:21.660,0:18:26.640
quite easily see the different volume[br]present, or the different conductivity
0:18:26.640,0:18:33.590
maps it's called, of a working lung and a[br]not so working lung right there.
0:18:33.590,0:18:41.410
Next steps. So what should we do to make[br]this technique better? What should we do
0:18:41.410,0:18:48.200
for OpenEIT to make it better? If you want[br]to innovate again, that's the github
0:18:48.200,0:18:53.460
project. Just go ahead. Oh that's an[br]avocado, it has a seat in the middle. Who
0:18:53.460,0:19:05.519
knew? I do. So I see the two main routes forward[br]as: One would be this low-cost biomedical
0:19:05.519,0:19:10.690
imaging for the developing world. You[br]could just stick with the static imaging
0:19:10.690,0:19:16.270
reconstruction because why not. you'd need[br]a few more electrodes than it currently
0:19:16.270,0:19:22.240
has. One of the main problems with the[br]technique is how you stick it to the skin.
0:19:22.240,0:19:25.730
So my suggestion for that is why don't you[br]just use a water bath and stick the body
0:19:25.730,0:19:31.929
part of interest in a body of water,[br]because water gets rid of a lot of the,
0:19:31.929,0:19:38.390
it's called the contact impedance problem.[br]Or, on the kind of exciting science front,
0:19:38.390,0:19:47.230
you've got the advancing neuroscience[br]option. Which would be measuring both high
0:19:47.230,0:19:50.340
spatial resolution and high time[br]resolution. So that's the non-invasive
0:19:50.340,0:19:57.710
electrophysiology solution. Or, and that[br]would be super awesome, there's a couple
0:19:57.710,0:20:03.629
of ways forward to do that and I'm going[br]to sort of discuss each of those.
0:20:03.629,0:20:10.169
So roughly there's physical configuration[br]improvements that could be done. There's
0:20:10.169,0:20:14.480
things that you can do to improve the[br]spatial resolution. There's things you can
0:20:14.480,0:20:19.480
do to improve the time resolution. And[br]this is interesting tack on at the end
0:20:19.480,0:20:25.210
that I thought I'd mentioned, which is[br]'write' functionality. So we're using very
0:20:25.210,0:20:33.090
small currents to read an image. What if[br]we pumped the current up a little before
0:20:33.090,0:20:38.939
you know it you're writing. I think not[br]invasive deep brain stimulation in a
0:20:38.939,0:20:48.670
focused way, that would be very very cool.[br]So, contact impedance. Major problem right
0:20:48.670,0:20:54.059
now, there is a well-known solution I[br]haven't done it yet you do this thing
0:20:54.059,0:21:00.909
called differential referencing, common[br]mode rejection should be done I haven't
0:21:00.909,0:21:05.069
done it that's the next step. That means[br]that it will work when you just attach it
0:21:05.069,0:21:10.630
with electrodes on the body. What happens[br]is, electrodes have a like some
0:21:10.630,0:21:16.620
capacitance and different amounts which[br]kind of interfere with the the measurement
0:21:16.620,0:21:19.690
that you want to make which you want to be[br]very accurate and just of your body. You
0:21:19.690,0:21:24.529
don't want to include the electrode[br]information in there that's changing.
0:21:24.529,0:21:30.110
There's a way to remove that that's well[br]known already. Another physical
0:21:30.110,0:21:34.870
configuration improvements: just increase[br]the number of electrodes. Wonderful, now
0:21:34.870,0:21:41.640
you've just improved the resolution. Or[br]the placing the part in water. Another set
0:21:41.640,0:21:46.700
of next steps would be on the mathematical[br]side. I mentioned that I use linear back
0:21:46.700,0:21:55.759
projection which is a wonderful technique,[br]that's how they do CAT scans. With X-rays
0:21:55.759,0:21:59.310
that's exactly what they do.[br]However, it makes some appalling
0:21:59.310,0:22:06.649
assumptions, like parent moves and[br]straight lines. That is not true. What you
0:22:06.649,0:22:11.209
should do is get a finite element model[br]and solve Maxwell's equations because
0:22:11.209,0:22:18.630
current bends around objects. Actually it[br]works in three dimensions too which might
0:22:18.630,0:22:23.639
not be all that surprising but it needs to[br]be solved for those three dimensions which
0:22:23.639,0:22:26.810
is why you just need to solve[br]Maxwell's equations and
0:22:26.810,0:22:30.899
create a finite element model.[br]And there's a quite a bit of work on
0:22:30.899,0:22:34.610
mathematical solutions that get higher[br]resolution.
0:22:34.610,0:22:42.189
That's another improvement area. And now[br]as I mentioned this awesome new technique.
0:22:42.189,0:22:44.649
Which, actualy there's a paper on[br]this year called
0:22:44.649,0:22:50.990
magneto-acoustic electical tomography.[br]You might remember
0:22:50.990,0:22:55.580
the FBI rule from high school.[br]When you have a current flowing,
0:22:55.580,0:23:02.429
perpendicular to that there will be a[br]force. Now that force, say it's vibrating
0:23:02.429,0:23:07.309
with 50 kilohertz. that's the AC signal[br]that you're sending through. Now you have
0:23:07.309,0:23:11.460
a vibrating compression wave. That's[br]sound. You can pick that up with a little
0:23:11.460,0:23:19.580
piezoelectric element. And that's actually[br]a focus of work. From that you can get
0:23:19.580,0:23:27.070
really good edge information, because as I[br]mentioned earlier, sound scatters at
0:23:27.070,0:23:31.460
edges. So you would also get the[br]electrical impedance tomography
0:23:31.460,0:23:38.549
information for the tissue sensitivity.[br]Why not combine those results together and
0:23:38.549,0:23:43.259
you would have a better tool. It currently[br]gets lesser resolution in the middle
0:23:43.259,0:23:50.180
simply from how you every combination of[br]electrodes just ends up having a less
0:23:50.180,0:23:56.799
dense number in the middle. You can also[br]do something as simple as increasing the
0:23:56.799,0:24:02.049
power that you send through if you're game[br]to do that. This is a kind of gory
0:24:02.049,0:24:07.961
picture. Right now epileptics, if they're[br]really troubled by their problem, which
0:24:07.961,0:24:13.460
they are often, they go into a hospital[br]have their brains opened up and they
0:24:13.460,0:24:18.580
stick this array on their head through[br]their skull. And they leave it open
0:24:18.580,0:24:24.340
for a week. And they try to induce[br]seizures through sleep deprivation.
0:24:24.340,0:24:30.440
And then they measure the activation[br]potentials that way to locate the foci or
0:24:30.440,0:24:36.200
where they going to do surgery to stop you[br]from having seizures. But it would be much
0:24:36.200,0:24:40.260
better and nicer if you could do it not[br]invasively and you probably can if you
0:24:40.260,0:24:43.600
improve the time resolution of EIT.[br]there's nothing stopping you from doing
0:24:43.600,0:24:50.360
that by the way. You just have to, like,[br]it's just a next step really.
0:24:50.360,0:24:56.919
And then I'll also mention write-[br]functionality. So there was a paper that
0:24:56.919,0:25:02.700
came out halfway through this year by a[br]guy called Neil Grossman (?) and what he
0:25:02.700,0:25:09.170
did is, he showed that you can stimulate[br]neurons by sending current through the
0:25:09.170,0:25:18.739
skull and in a focused way. Now why that's[br]interesting is, you can non-invasively
0:25:18.739,0:25:23.190
stimulate neurons. So that's the write-[br]functionality. It's unknown what
0:25:23.190,0:25:27.950
resolution is or how well you could[br]control the the focal point here. But it
0:25:27.950,0:25:34.220
works in the principle of beat frequencies[br]so he sent through two kilohertz and 2.05
0:25:34.220,0:25:42.379
kilohertz and basically had a beat[br]frequency of 10 Hertz arise from that and
0:25:42.379,0:25:50.279
basically stimulated neurons in this area[br]that he can control via an x- and y-axis
0:25:50.279,0:25:59.940
which is very impressive. Leaves a lot of[br]questions open. Those are some possible
0:25:59.940,0:26:06.309
next steps that it could go in. Obviously[br]I think this is interesting. I hope that
0:26:06.309,0:26:11.340
you do too. I'd love it if you would want[br]to sign up to a mailing list I'll give a
0:26:11.340,0:26:17.049
link on the next page. If you want to[br]collaborate email me. If you know any
0:26:17.049,0:26:22.070
funding bodies that might be interested in[br]the developing medical imaging for
0:26:22.070,0:26:26.330
the third world I'd love to be put in[br]contact. If you wanted a kit and, if there
0:26:26.330,0:26:30.230
were enough people that wanted a kit,[br]probably of the next version which would
0:26:30.230,0:26:36.200
have 32 electrodes sign up to the mailing[br]list, talk to me. Thanks.
0:26:36.200,0:26:46.820
applause[br]Rintoul: Thank you
0:26:46.820,0:26:49.690
applause Herald Angel: Thank you[br]very much. We have a little bit
0:26:49.690,0:26:57.610
time for Q&A. And please if you have to[br]leave the room make it in a very quiet
0:26:57.610,0:27:05.730
way. So is there ... there are some[br]questions I've seen microphone 4 first.
0:27:05.730,0:27:08.970
Please go ahead.[br]Audience member: So, a great thing
0:27:08.970,0:27:15.649
thinking about developing countries and[br]getting them medical tech. But at the very
0:27:15.649,0:27:20.889
first beginning you said imagine a world[br]where this imaging would be all available
0:27:20.889,0:27:26.610
like every day and it creeped me out a[br]little bit. Do you really think that it's
0:27:26.610,0:27:33.740
a good idea to go in the shower in the[br]morning and have your I don't know your
0:27:33.740,0:27:40.019
bathtub telling you that there is a small[br]mass inside your lungs.
0:27:40.019,0:27:46.889
Rintoul: That's a good question. Basically[br]the question was: There's a privacy
0:27:46.889,0:27:52.360
concern with looking inside your body. It[br]doesn't sound that great to some people.
0:27:52.360,0:27:56.200
To those people I would say you should[br]turn off I know that sounds a little
0:27:56.200,0:28:05.179
harsh. But please just turn it off, don't[br]use it. And with all scientific movements
0:28:05.179,0:28:12.080
forward comes great risk, I also say. And[br]it can be used for good or evil and it's
0:28:12.080,0:28:17.769
up to us as a society how we want to[br]choose to use it. And how we structure
0:28:17.769,0:28:24.510
ourselves and potentially motivate and[br]incentivize corporations to use it in a
0:28:24.510,0:28:31.919
responsible way. Part of making this open[br]is I hope that, basically if people have
0:28:31.919,0:28:36.470
access to it you can choose for yourself[br]how you'd want to use it.
0:28:36.470,0:28:40.809
Herald Angel: And next question would be[br]from the Signal Angel please.
0:28:40.809,0:28:45.070
Signal Angel: Yes I have a couple of[br]questions from the internet. First of all,
0:28:45.070,0:28:51.439
what type of AC frequencies in use? the[br]asker assumes sinusoidal but he wonders if
0:28:51.439,0:28:54.779
you also tried square wave, triangular and[br]other shapes.
0:28:54.779,0:29:00.360
Rintoul: That's also a really interesting[br]question. It's about what kinds of waves
0:29:00.360,0:29:08.580
are used, what kinds of AC signals.[br]Typically it's done with AC sine waves
0:29:08.580,0:29:14.500
ranging all over the place, depending on[br]what application you want to use up for. I
0:29:14.500,0:29:19.980
mentioned multi frequency EIT for cancer[br]detection. That uses a lot of different
0:29:19.980,0:29:26.090
frequencies so if you wanted to use other[br]waveforms I think that would be really
0:29:26.090,0:29:32.840
interesting. Nobody's tried, you can, that[br]should be done.
0:29:32.840,0:29:38.740
Herald: So since there's a big queue on[br]microphone 3 I would go there please.
0:29:38.740,0:29:44.630
Audience member: Yes I have a technical[br]question. Assuming that you won't use this
0:29:44.630,0:29:50.590
techniques on humans or organic matter at[br]all and what are the limitations for the
0:29:50.590,0:29:56.190
resolution. The spatial resolution. And is[br]there a possibility to reduce the spatial
0:29:56.190,0:29:59.100
resolution.[br]Rintoul: You mean increase the spatial
0:29:59.100,0:30:06.179
resolution or reduce it?[br]Audience member: Reduce the voxel size
0:30:06.179,0:30:12.470
Rintoul: So increase the spatial[br]resolution. Yes absolutely. So I was
0:30:12.470,0:30:16.240
trying to go through a few of the next[br]steps that could get to that. One of them
0:30:16.240,0:30:21.259
is magneto-acousto electrical tomography[br]because you get two different types of
0:30:21.259,0:30:27.580
information which you could put together[br]to form a higher resolution image. So
0:30:27.580,0:30:33.320
that's one way and if you didn't need to[br]worry about human safety I recommend you
0:30:33.320,0:30:39.240
just turn the power up, that will also[br]work.
0:30:39.240,0:30:46.389
Herald: Okay I think we go back to the[br]signal angel for one short one please.
0:30:46.389,0:30:49.890
Signal Angel: Yes I have another question[br]from the internet. from a doctor this
0:30:49.890,0:30:54.340
time. He wonders if there are any clinical[br]studies that compare pulmonary edema
0:30:54.340,0:30:59.919
diagnostics with EIT to ultrasound and why[br]don't we just work on cheap ultrasound
0:30:59.919,0:31:03.139
instead.[br]Rintoul: That's a good question. People
0:31:03.139,0:31:08.289
are working on cheap ultrasounds.[br]Ultrasound gives different information to
0:31:08.289,0:31:14.360
EIT. It has a problem of the sound[br]scattering. So it's a different type of
0:31:14.360,0:31:21.289
information which has different pros and[br]cons. And and I think people should make
0:31:21.289,0:31:27.169
cheap ultrasound. And I would like to see[br]the hybrid modality come together. You can
0:31:27.169,0:31:31.769
get really good tissue distinction with[br]EIT so there's pros and cons.
0:31:31.769,0:31:36.680
Herald: Okay then, microphone 2 please.[br]Audience member: You had a really good
0:31:36.680,0:31:44.649
talk my question so far you always need[br]direct contact to the electrode, right? So
0:31:44.649,0:31:50.519
it has to be direct contact or in water.[br]Is there way to detect or measure the
0:31:50.519,0:31:56.659
signal without direct contact? So maybe in[br]if the if the object is in air or any
0:31:56.659,0:32:01.419
other gas?[br]Rintoul: Right. I wish there was. No is
0:32:01.419,0:32:07.570
the short answer. Unless ...[br]Audience member: Any research on making it
0:32:07.570,0:32:11.129
happen?[br]Rintoul: Well yeah you can you can use
0:32:11.129,0:32:20.129
X-rays. They work wonderfully to to go[br]through the air. But if you use them I
0:32:20.129,0:32:24.220
mean you do increase your chance of cancer[br]so don't use them all the time on
0:32:24.220,0:32:29.499
yourself. Again CAT scanners are a little[br]bit expensive.
0:32:29.499,0:32:35.529
Herald: Thank you and I think we have time[br]for one more from microphone 3
0:32:35.529,0:32:41.970
Audience member: My question would be[br]what, so maybe I've missed it, but what's
0:32:41.970,0:32:47.009
the order of magnitude for cost so would[br]this be feasible at like a hackerspace for
0:32:47.009,0:32:53.749
this to implement. And does the industry[br]see the possibility to make money.
0:32:53.749,0:33:00.779
Rintoul: Yes a lot of those sort of these[br]early like R&D papers yeah they should be
0:33:00.779,0:33:06.870
applied and you could make money with it[br]absolutely. And there's no component in
0:33:06.870,0:33:14.960
there that costs more than a couple of[br]cents. I suppose a cortex m3 like costs a
0:33:14.960,0:33:19.570
couple of dollars. And I mean I don't know[br]what your budget is but yes you I think
0:33:19.570,0:33:24.309
you could do this in a hackerspace without[br]any problems. There's nothing stopping
0:33:24.309,0:33:29.590
anyone from doing this and as we know[br]microcontrollers are becoming cheaper and
0:33:29.590,0:33:36.460
cheaper. So why not.[br]Herald: I don't get Hasty's signs from the
0:33:36.460,0:33:40.059
sideline so I think I can take another[br]question from 2 please.
0:33:40.059,0:33:46.600
Audience member: So far you have showed us[br]images of 2d planes. What about volumes
0:33:46.600,0:33:52.369
Rintoul: Yes so there's work on solving[br]for volumes using finite element models
0:33:52.369,0:34:02.759
and solving Maxwell's equations. Basically[br]I just did the shortest route to reach
0:34:02.759,0:34:07.670
image reconstruction that was available[br]which was linear back projection which is
0:34:07.670,0:34:12.280
typically done in a 2d plane. So[br]absolutely, you can do it in three
0:34:12.280,0:34:16.370
dimensions.[br]Herald: So I'm very sorry we are out of
0:34:16.370,0:34:23.550
time the queue back there you can have the[br]chance to chat with our speaker just right
0:34:23.550,0:34:31.880
now. The next talk coming up is in about[br]15 minutes and it's I think also in
0:34:31.880,0:34:36.920
English. See you then and a big round of[br]applause for our speaker, excuse me.
0:34:36.920,0:34:42.460
applause
0:34:42.460,0:34:47.725
music
0:34:47.725,0:35:04.000
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