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Paweł Moskal: Medical imaging with anti-matter

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Ladies and gentlemen, as Paul [said], my hobby, and at the same time profession, is physics. And this is, for me, a very lucky coincidence. And I think, as Democritus once said, I can also repeat now, that I would rather prefer to discover one causal law than be King of Persia. And I am pretty sure there is a lot of phenomena awaiting our discovery... Oh, let me know... Yeah, it's working. [Phenomena] which are occurring, perhaps, even now, here, but we do not recognize them. And I have my personal proof for that, at least it is convincing [to] me. That was an astonishment I experienced once, when working at this nice, and even cozy accelerator, when a friend of mine came to my office, and... (Phone rings twice) And something like that happened, and then he [said], "Please pick it up, because this is an external call." So I excused [myself] for a moment, and then it was, indeed, an external call. And then I asked him, "How do you know that?" And this was the explanation. This was the external call... (Phone rings twice) And this is an internal call. (Phone rings once) (Laughter) Many of you are also working in institutions, you recognize that, perhaps. I [had been] working there for many years, in that office, and didn't realize that. (Laughter) And this was... I learned a good lesson of humility. A painful lesson for the researcher whose ambition is to [discover], say, less trivial things than that. (Laughter) So... (Laughter) But this also gave me a promise that there is a chance to discover something -- (Laughter) [Something] I didn't notice till now. And today, I would like to tell you a story more successful, for me, at least, about antimatter-based molecular imaging of the whole human body. So, what do I mean by that? So I would like to tell you about an idea, or invention. About a cylinder, a device which [will] one day perhaps surround a person. And with that device, I hope, we will be able, in the future, to make tomographic images, non-invasive pictures of the human body, of the whole human body. So perhaps a less scientific topic of my presentation today could be: "How I have reinvented the cylinder." But now, after you laughed truly when Charles Crawford was showing a formula, I think I'm obliged now to give a lesson, before we go farther off solid-state physics, atomic physics, nuclear physics, and then, at the end, particle physics. That's all we need to understand the rest of the talk. (Laughter) But... (Laughter) Then, [looking at] some of you, I see colleagues from my institute [here], younger, [who] have perhaps already attended such lectures. I will [do] this in a way I'm sure none of you have [been] shown, because I would like to start from -- I should point it here -- from the bush I made a photo of in my garden. So, as a researcher, you might put [your] head inside it, and then you recognize there is a lot of fruits there. But with a scope, perhaps you could go farther. And now, let us skip molecular physics. These fruits are surely from molecules, and the molecules are from atoms. (Laughter) (Applause) So, now...(Applause) Now we are already at atomic physics, and this is, now -- (Laughter) [It's] very important to recognize that -- and this is really important for the rest of the talk -- that this is not to scale, and I could not -- (Laughter) [I] could not plot it to scale, because the nucleus is much smaller, in comparison to the size of the atom. And that is why some of the particles can just traverse through the human body, or through matter, if they are energetic enough. And then, in the next [figure], let us go to nuclear physics. This is the nucleus. And then, quickly, to particle physics. The nucleus is [composed of] quarks. And now, going back to the word "antimatter," now [we have] really come to the point. There are also quarks and anti-quarks. So, they are the objects which I am really studying in my daily life. [They] are called mesons, not important for this talk, but I am doing that so I had to mention that. (Laughter) And mesons are built out of matter and antimatter. And that's why they can only live [a very short time]. If that quark and anti-quark touch each other, it disappears in the form of energy. And now, for the imaging, we need something similar. But we cannot have a meson in the laboratory, because it lives [only] for a while, not worth mentioning. But there is another source of antimatter that we [do] have in the laboratories, in most nuclear physics laboratories, which [are] the isotopes, the atoms, or substances, like fluorine, like oxygen, but which can radioactively decay. And this we all know. But there is one radioactive decay which is very special. Which out of those three [types], Alpha, Beta and Gamma, Beta is the most mysterious one, or the most mystic [one]. And this is like that. One of the nucleons inside the nucleus, decays, as it was shown here. Oh, let me come back. To an anti-electron, it is e+ here. It's not an electron, but an anti-electron. The electron has a "minus." And this is an anti-electron. This is something which, if it touched the electron, then annihilation [would] occur, and you would have energy. So now, which is already used in the world, you can cheat a little, and make, for example, radioactive sugar, instead of usual sugar. The radioactive sugar is just sugar, made, for example, with fluorine, but instead of usual fluorine, you take radioactive fluorine, which then emits positrons, those anti-electrons. And you [can] administer that to the patient like you see in that picture. And then, all the processes with the sugar which occur in the body, are exactly the same as with the usual sugar, but from time to time you have a signal from the interior of the body, because this decay happens there. And now, if you look -- If this decay happens somewhere, you have this anti-electron. If it touches the electron -- we are in the first order, from electrons and those nuclei, nothing else. So if it touches this electron, then they annihilate, because it was matter and antimatter. And those two photons, two gamma quanta, are flying in a line, apart from each other. And they are energetic, energetic enough to go through atoms. So they can go outside of the body. And now, we are close to the explanation of that word. So we had a positron, we had emission, and now we have detectors, so we have Positron Emission Tomography, with those detectors. Now it's enough to put [detectors] around the human body, which are capable of detecting those gamma quanta. And you can [take] a picture of the interior of the body, or [first of all], you can [take] a picture of where those sugars were distributed around the organism. And now, you may wonder how one can do that. I have an easy example, the simplest one. Let's assume [all] the sugar administered was just absorbed in one place in the brain. Let's say that that [unfortunate] person had a [tumor], and this was absorbed really point-like, in one place. Then, it's very easy to imagine how you can [take] a picture of that brain, or that point, Because what we measure... (Camera shutter sound) Let's say those points, those blue rectangles, are detectors. Something which can register. OK, a bulb. If you put a current into the bulb, then you see the light. If you put the light to the detectors, you see the current. Shall I say, it's an anti-bulb. So what [do] we have? We... We [administered] a sugar, then that sugar is sometimes decaying somewhere. In that case, it's always decaying here. And we measured the signal here and here. There is a lot of cables there. But we know it was here and here. So what we do is to plot a line. But we don't know [where] this sugar was, along this line. But it's of course decaying in different directions. (Shutter sound) So it's enough to have two such lines, (Shutter sound) and you know the point. So now it's very easy to imagine that you can [take] such a picture of the [whole] body. OK, it's not as easy as I plot it now, but... (Laughter) But it's imaginable. And this is how a person sees that. So you put [them into a] plastic box, and then on the screen you have [an image] of your brain. But now, what is the problem to be solved, or what is the challenge here. The challenge is that such devices are very expensive, 20 million Polish zlotys. That's one. So there is only a few of them in Poland. They are short. It means you cannot make an image of the whole person. As you saw in this picture, there are short rings around the patient. And now, there is one more problem, or a challenge. How to improve the sharpness of that image? And now, please look at that picture here. This is a picture that I would like to [use] to [explain] the problem with the smearing of the image. So, let's say this anti-electron touched an electron here -- we had two photons, two gamma quanta, and they react here and here. But we don't know this. We know only that it was somewhere in the detector. Because we have here a cable, and the signal from the detector. Ah, sorry. (Camera shutter sounds) Sorry. So now, what we can plot is the line from the middle of the detector to the middle of the detector. So we make a mistake. Because, in that case, we know the true line is here, but we reconstruct that line. And this caused the smearing of the image. So now, there is one trivial way to overcome this. The trivial way is to make these detectors smaller and smaller, but then you increase and increase the cost, because you increase the number of the bulbs. And this is, now, the idea I had. Just, instead of making that, let's change the paradigm completely. Let's use a huge block instead of small pieces. And let's try to find something out when the gamma heated the detector inside. And this is just the idea, which is the direct transfer of the detectors we have in that experiment. This is one of the experiments I spent perhaps 15 years researching. And with those detectors we were studying those mesons. And we were measuring -- this is part of the accelerator -- we were measuring the time [in which] particles travel from there to here. This is nanoseconds, a very short time. But if you look at that -- These were strips of plastic material which allowed to measure the particles. In a closer view, it may be plotted like that. You have a strip of the material. If something hits it, a particle, a gamma quantum, then there is a light inside, and if it is in the middle, then the time of the light signal to that side, to this bulb, and to that bulb, is the same. If it is closer to that -- "PM" is not the abbreviation of my name, it is "photomultiplier." (Laughter) If it is closer to that, then this time is shorter, this time is longer. So from the difference of times, you can define when this gamma quantum really hit it. Very simple. This is used in all physics experiments, particle and nuclear physics experiments. And now, the only thing to [do was], how to make a tomograph [out of that]. And then -- this is again something like reinventing the circle, one can think of taking this wall of those strips, and making a cylinder out of that. And now, you have those strips. You can put a bulb here, a bulb there, so you know when this gamma from the human body hit, and in which way. You can put a patient here, inside. This can be large. The number of those photomultipliers, of those bulbs, does not increase when you enlarge that. You may make this as large as you like. Even more, you can make more of such cylinders. And then, you can increase the probability of detecting these gamma quanta. So now, the dream which we are trying to realize with my colleagues, is to build such a tomograph, which would allow for such molecular imaging of the whole human body. Now it's clear. But now, what -- (Beep) What is with that? (Phone rings twice) Now, you may believe it or not, I conceived [of] that cylinder out of that detector which you saw. But then, I realized that I was working in collaboration with a laboratory who has such a cylinder. This is the one in Italy. 4 meters large, with scintillators, with those materials, and we are [doing] experiments there. Then, when preparing this talk... Oh, that again. (Phone rings once) I realized that I was working on an experiment which had such a huge barrel of scintillator. And I am working on another experiment, which when you look inside, there is again a barrel of scintillator. So, you may [see] here how large those barrels are. A person could even walk inside, if this [worked]. So there is a chance to really [make] such a tomograph, especially that such technology is used nowadays, in particle and nuclear physics. And I hope, like Rafał told us, that somebody will take his message seriously, and somebody clever will just make this tomograph in some groups which are rich enough to build all those bulbs, and so on. But independently, I and my colleagues are trying to do that here in Cracow. And then... (Phone rings twice) This is just to point to the end of my talk. Thank you very much. (Applause)

Video Details

Duration: 17 minutes and 18 seconds
Country: Poland
Language: English
Genre: None
Producer: TEDxKraków
Director: TEDxKraków
Views: 781
Posted by: tedxkrakow on Dec 15, 2010

Talk delivered at TEDxKraków, on October 15, 2010.

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