WEBVTT - How MRI Works 0:00:01.480 --> 0:00:04.280 Welcome to Stuff you Should Know, a production of I 0:00:04.360 --> 0:00:13.880 Heart Radio. Hey, and welcome to the podcast. I'm Josh Clark, 0:00:13.920 --> 0:00:16.760 There's Charles w Chuck Bryant, and Jerry is with us 0:00:16.800 --> 0:00:20.360 as we journey into the heart of the magnetic darkness 0:00:21.079 --> 0:00:27.360 known as an m r I machine, the Wonder Machine. 0:00:27.760 --> 0:00:30.440 After all these years of talking about this thing, I 0:00:30.480 --> 0:00:34.520 finally get it. I know it. It's crazy. We've been 0:00:35.560 --> 0:00:37.720 kind of amazed by it and then a little bit 0:00:37.800 --> 0:00:40.040 turned off by it. But then we realized it's not 0:00:40.080 --> 0:00:42.600 the machine itself, it's the way it's being applied. And 0:00:42.640 --> 0:00:44.760 so we kind of came back to it again and 0:00:44.880 --> 0:00:48.000 it nuzzled us and it's bore and it got kind 0:00:48.040 --> 0:00:51.960 of sexy. Yeah, and we're also guilty of the f 0:00:52.159 --> 0:00:54.520 m r I crime that now I kind of feel 0:00:54.520 --> 0:00:59.880 bad about. What is that? Is that a Queen's Right album? Yeah, 0:01:00.080 --> 0:01:02.520 maybe we'll just talk about that later when it's appropriate. 0:01:03.440 --> 0:01:05.920 What the Queen's Right album? No, the fm R I 0:01:06.040 --> 0:01:10.720 blunder that we've been making for thirteen years. Sure, I 0:01:10.760 --> 0:01:13.119 feel like, okay, all right, we'll go over that. Fine, Fine, Fine, 0:01:13.120 --> 0:01:14.959 I don't want to miss anything. But instead we're gonna 0:01:15.000 --> 0:01:17.280 mostly talk about the m R I the Wonder Machine 0:01:17.840 --> 0:01:21.039 as it is, because Chuck, we were always just amazed 0:01:21.080 --> 0:01:23.640 by it to begin with, but now that I understand it, 0:01:23.720 --> 0:01:26.640 I feel even more amazed by it. I'm I'm proud 0:01:26.680 --> 0:01:29.880 of humanity for having come up with this thing. Yeah, 0:01:29.959 --> 0:01:32.800 I mean, it's pretty amazing that. And we'll talk about 0:01:32.880 --> 0:01:34.720 the history of it and everything in a sect, but 0:01:35.319 --> 0:01:41.039 it's amazing that human beings uh got together with their 0:01:41.080 --> 0:01:45.240 cohorts and said, you know what we can do. The 0:01:45.360 --> 0:01:49.560 human body is made up of sixty six water, So 0:01:49.720 --> 0:01:52.360 let's figure out how to use magnetic fields and radio 0:01:52.360 --> 0:01:56.240 waves to measure that water, uh and the tissues of 0:01:56.280 --> 0:01:58.440 our body, and then we can map it and then 0:01:58.480 --> 0:02:02.840 we can image it. Right. And so those initial people 0:02:02.880 --> 0:02:04.920 who said that were burned at the steak because it 0:02:04.960 --> 0:02:08.040 was like the sixteenth century still. But when a few 0:02:08.040 --> 0:02:11.239 more hundred years passed, a few new people came onto 0:02:11.280 --> 0:02:16.000 the scene, and they encountered a completely different environment um, 0:02:16.080 --> 0:02:18.600 one that was kind of nurturing of science and advancement 0:02:18.639 --> 0:02:20.560 in the idea that you could see inside the human 0:02:20.600 --> 0:02:24.440 body without cutting it open. And the person who won 0:02:24.520 --> 0:02:27.160 what actually kind of interestingly turned out to be a 0:02:27.240 --> 0:02:31.400 race among researchers who were um all trying to sell 0:02:31.560 --> 0:02:34.840 solve the same problem at the same time. Independently was 0:02:34.840 --> 0:02:39.960 a guy named Dr Raymond Domadian or damedian Um, and 0:02:40.040 --> 0:02:42.560 he is credited as the first person to invent the 0:02:44.120 --> 0:02:49.000 fully functional human sized m R. But he's one of 0:02:49.440 --> 0:02:52.520 typically at least three people who are credited with with 0:02:52.639 --> 0:02:55.639 inventing the m R I, if that makes sense. Yeah, 0:02:55.680 --> 0:02:58.840 I mean when he got in there in July of 0:02:58.960 --> 0:03:02.520 nineteen seventy seven and nothing really happened, and I think 0:03:02.639 --> 0:03:04.839 one of his colleagues said, hey, maybe you're too big 0:03:04.880 --> 0:03:08.399 for this thing. They put in a smaller person and 0:03:08.639 --> 0:03:10.679 it worked for the first time. It took about five 0:03:10.680 --> 0:03:14.639 hours to get an image. Uh. They named the thing Indomitable, 0:03:15.000 --> 0:03:17.480 and if you look up pictures, it's in the Smithsonian 0:03:17.520 --> 0:03:20.960 now of Indomitable. You know. It's it's one of these 0:03:21.000 --> 0:03:24.240 things that looks like a bare bones version of what 0:03:24.280 --> 0:03:27.400 it ended up looking like. It's like the the MRI 0:03:27.480 --> 0:03:30.480 I version of a wicker wheelchair. All be sort of 0:03:30.560 --> 0:03:33.200 did you you didn't see a picture? No, because I 0:03:33.240 --> 0:03:36.080 suspected as much. I didn't want it to haunt my dreams. Yeah, 0:03:36.120 --> 0:03:38.080 I mean it looks sort of like this big donut. 0:03:38.240 --> 0:03:40.720 I think the difference in this one is that it 0:03:40.760 --> 0:03:42.880 shows and it may I'm not sure if it's doctor 0:03:43.440 --> 0:03:46.280 Demadian in the photo or not, but they're actually wearing 0:03:47.400 --> 0:03:51.760 some coils around their body. Um, but there is a 0:03:51.840 --> 0:03:54.720 larger donut as well. Do they look like they're on 0:03:54.800 --> 0:04:00.000 craft work tour? Sort of? Sort of? So they were 0:04:00.080 --> 0:04:03.480 to other people. Demandian was the first one. I'm glad 0:04:03.520 --> 0:04:07.120 that we settled on a pronunciation, by the way, um, 0:04:07.160 --> 0:04:09.320 and he was the first one to cross the finish line. 0:04:09.320 --> 0:04:11.320 But there were the two others who were working on 0:04:11.360 --> 0:04:18.400 that same problem, Paul Lauderbergh and Sir Peter Mansfield. And 0:04:18.960 --> 0:04:21.359 like I was saying, they were all working independently on 0:04:21.400 --> 0:04:24.920 this problem. This thing that had been demonstrated in called 0:04:25.000 --> 0:04:28.680 nuclear magnetic residence, which which is that you can make 0:04:28.720 --> 0:04:31.760 Adams do really peculiar things when you put them in 0:04:31.800 --> 0:04:36.039 the presence of um, a magnetic field. If it's strong enough, 0:04:36.040 --> 0:04:39.200 it kind of snaps them all into attention. Uh. They 0:04:39.240 --> 0:04:41.719 click their heels and they say, yes, sir, I'll get 0:04:41.760 --> 0:04:45.560 that pette for you immediately. And um, that's not how 0:04:45.640 --> 0:04:49.520 they normally behave. And so these guys Demardian, Lauderboro, and 0:04:49.560 --> 0:04:52.280 Mansfield all were like, somehow, some way, there's a way 0:04:52.320 --> 0:04:57.080 to use this, to to use this nuclear magnetic residence 0:04:57.160 --> 0:04:59.240 to look inside of the body. And that's what they 0:04:59.320 --> 0:05:01.880 said about try to do. Yeah, and pretty early on 0:05:01.920 --> 0:05:05.360 they cut the word nuclear out of it and went 0:05:05.400 --> 0:05:08.159 with imaging. So m R. I was born. I think 0:05:08.440 --> 0:05:10.920 it wasn't probably a great time, and maybe it's never 0:05:10.960 --> 0:05:15.039 a great time to throw the word nuclear into anything. Uh. 0:05:15.160 --> 0:05:17.960 You know, every everything from nuclear power to nuclear bombs 0:05:18.160 --> 0:05:22.080 have a bad rap quite frankly. Yeah, it gets even 0:05:22.120 --> 0:05:26.040 worse if you pronounce any nu oh man. Uh. And 0:05:26.080 --> 0:05:28.280 then there was someone else we do need to shout out, 0:05:28.360 --> 0:05:34.200 a physicist by the name of uh cig Ogawa or Ogawa. 0:05:34.480 --> 0:05:38.919 How would you pronounce that it's any value? See in 0:05:39.000 --> 0:05:43.800 Japan just screams to be pronounced independently. Oh really they 0:05:43.920 --> 0:05:48.200 love so C C G E SAG. That's what I 0:05:48.200 --> 0:05:51.080 would go with. Okay, I'm serious, I really think you know, 0:05:51.120 --> 0:05:54.960 I believe it just sounded funny. Um. And so what happened, 0:05:55.279 --> 0:05:57.920 Uh So while we're shouting this person out is because 0:05:57.960 --> 0:06:02.599 they discovered the if you have oxygen poor hemoglobin, it's 0:06:02.600 --> 0:06:06.159 gonna react differently by this magnetic field that's created in 0:06:06.200 --> 0:06:09.960 the m r I machine than really good oxygen rich hemoglobin, 0:06:10.600 --> 0:06:14.440 and that that contrast, you could basically eventually end up 0:06:14.480 --> 0:06:18.560 seeing blood flow, like imaging blood flow. Yeah, because with 0:06:18.720 --> 0:06:22.760 Demai and his cohort were doing, we're imaging tissues inside 0:06:22.760 --> 0:06:26.280 of the body. Um Ogawa said, well, actually you can 0:06:26.320 --> 0:06:29.159 track the flow of blood in those tissues as well. 0:06:30.400 --> 0:06:33.000 Laid the groundwork for what became f m r I 0:06:33.080 --> 0:06:37.320 functional MRI I, and then also more importantly magnetic resonance 0:06:37.400 --> 0:06:40.479 and geography, which is basically tracking blood flow in blood 0:06:40.560 --> 0:06:44.040 vessels in real time. Basically, Yeah, and all this stuff 0:06:44.120 --> 0:06:47.200 was revolutionary because a, um, you really nail it on 0:06:47.240 --> 0:06:49.400 the head earlier, like you don't have to cut people 0:06:49.440 --> 0:06:52.920 open anymore to see this stuff. Um. We we've had 0:06:53.000 --> 0:06:56.520 X rays for a long time and they're great if 0:06:56.560 --> 0:06:58.800 you want to look at certain things like your your 0:06:58.800 --> 0:07:01.920 bones and see if you've got a cracked rib or something. 0:07:02.520 --> 0:07:05.240 But when it comes to soft tissue, X rays were useless. 0:07:05.880 --> 0:07:08.400 We'll talk a little bit more about CT can CT 0:07:08.560 --> 0:07:11.520 scans and why they're awesome in their own way. But 0:07:11.600 --> 0:07:16.120 not still not as I guess functional as an m 0:07:16.200 --> 0:07:19.760 r I. Well plus CT scans. I didn't realize this. 0:07:20.000 --> 0:07:23.480 Ct s computed tomography. They use X rays as well, 0:07:23.600 --> 0:07:26.240 so you're still getting that dose of radiation from a 0:07:26.320 --> 0:07:29.680 CT scan too, all right. So all that is just 0:07:29.760 --> 0:07:31.240 to lead up to say that the m R I 0:07:31.320 --> 0:07:35.040 just beats them all those other machines stink. It truly 0:07:35.080 --> 0:07:38.680 earns his nickname the Wonder Machine. Um boy, I feel 0:07:38.680 --> 0:07:40.680 like like we should take a break before diving into 0:07:40.800 --> 0:07:43.680 this thing, should we? I'm thinking, hold on, yeah, I 0:07:43.680 --> 0:07:45.840 think this is a good spot for a break. Okay, 0:07:45.920 --> 0:08:20.680 let's do it. Okay, so we're back and uh, a 0:08:20.680 --> 0:08:23.000 bit of an early break, but that's because we're about 0:08:23.000 --> 0:08:26.760 to get in the weeds with the actual nuts and bolts. Ironically, 0:08:26.840 --> 0:08:29.280 probably doesn't have any nuts and bolts. Oh that's a 0:08:29.320 --> 0:08:34.240 good point. It's probably probably what heavy duty plastic ribbons. 0:08:34.440 --> 0:08:37.360 I don't know. It might just be like large solid 0:08:37.400 --> 0:08:41.079 injection molded pieces. That's a good question. We should have 0:08:41.120 --> 0:08:44.320 learned that. But anyway, the metaphorical nuts and bolts of 0:08:44.360 --> 0:08:46.880 this thing, Uh, if you've ever seen when they look 0:08:46.920 --> 0:08:50.360 like a big doughnut, you sit on a a little 0:08:50.480 --> 0:08:54.560 you know, it looks like a mortuary tray and you 0:08:54.640 --> 0:08:58.680 get slid in through this hole in this tube. It's 0:08:58.679 --> 0:09:03.520 only about is in diameter. So they're not great if 0:09:03.640 --> 0:09:07.880 you are claustrophobic. But they do make machines that aren't 0:09:07.960 --> 0:09:10.040 quite They don't give you quite what you want with 0:09:10.080 --> 0:09:12.719 a closed system, but they're a little more opened up. Yeah, 0:09:12.800 --> 0:09:15.240 and I got the impression that they're starting to really 0:09:15.320 --> 0:09:18.360 kind of revisit those because you can't produce quite as 0:09:18.520 --> 0:09:21.439 as great a magnetic field is powerful a magnetic field 0:09:21.440 --> 0:09:23.880 with an open system, But I think they're starting to 0:09:23.920 --> 0:09:27.480 figure out you don't necessarily need the most powerful magnetic field, 0:09:27.520 --> 0:09:32.520 so stay tuned for that in ten years. But um, 0:09:32.720 --> 0:09:35.280 the most important part of the whole m r I 0:09:35.400 --> 0:09:38.480 machine obviously is the magnet. That's what produces the magic. 0:09:38.640 --> 0:09:43.800 Is this magnetic field that so that doughnut, that elongated 0:09:43.840 --> 0:09:47.320 doughnut that you're slid into in the tube, that is 0:09:47.520 --> 0:09:51.079 the magnet basically, And it's not like a magnet like 0:09:51.120 --> 0:09:53.880 you'd put on your fridge. It would suck your fridge 0:09:53.920 --> 0:09:56.520 into what amounts to a black hole basically, if you 0:09:56.600 --> 0:09:59.080 got your fridge anywhere near this thing. It's a different 0:09:59.120 --> 0:10:02.240 kind of magnet. It's a super conducting magnet made up 0:10:02.360 --> 0:10:07.440 of coils, probably copper coils that an electrical current is 0:10:07.559 --> 0:10:10.640 run through. And when you run an electrical current through 0:10:11.840 --> 0:10:16.440 a coiled um set of metal, you can produce a 0:10:16.480 --> 0:10:20.720 magnetic field that's great, like fantastic. But to produce the 0:10:20.800 --> 0:10:23.760 kinds of like the powerful magnetic fields that they're producing 0:10:23.760 --> 0:10:26.080 in an m r I, you actually need a super 0:10:26.120 --> 0:10:31.200 conducting magnet, and that's just a whole another level. Yeah. 0:10:31.320 --> 0:10:34.640 I mean, if you want to create a very large 0:10:34.640 --> 0:10:37.880 and stable field, and we're talking, I think they measure 0:10:38.840 --> 0:10:44.760 magnets and is it or gauze. I think goss g 0:10:45.000 --> 0:10:48.480 A U S S so goss is the measurement. One 0:10:48.520 --> 0:10:52.600 tesla is ten thousand goths. So if you're looking at 0:10:53.080 --> 0:10:56.600 just a regular fly by night MRI I wonder machine, 0:10:57.240 --> 0:11:01.120 you're looking at about one point five roughly one point 0:11:01.120 --> 0:11:05.560 five tesla, or about fifteen thousand goths as far as 0:11:05.600 --> 0:11:08.760 the magnetic field goes. And that's um compared to a 0:11:08.760 --> 0:11:13.040 point five for the magnetic field of planet Earth. You're 0:11:13.080 --> 0:11:17.080 not point five tesla point five goths thousands, it's like 0:11:17.080 --> 0:11:20.240 fifty sixty thousand times more if you're an average machine. 0:11:20.559 --> 0:11:22.480 But they even make him go all the way up 0:11:22.520 --> 0:11:28.760 to ten tesla, Yeah, which is what a hundred thousand goths. Yeah. 0:11:28.760 --> 0:11:32.160 And the more goss, the more uh, the prettier machine 0:11:32.240 --> 0:11:35.800 is just getting the prettier pictures are. Yeah. Another thing 0:11:35.840 --> 0:11:38.160 that I saw though, is that they're figuring out that 0:11:38.240 --> 0:11:42.120 when you get past a certain tesla of magnetic field, 0:11:43.960 --> 0:11:47.000 it does matter, and that it actually gets worse because 0:11:47.040 --> 0:11:50.000 you're picking up so much detail that you can't tell 0:11:50.320 --> 0:11:53.280 a bit from a bob basically, and if you're a 0:11:53.400 --> 0:11:55.920 radiologist using terms like bits and bobs, you need to 0:11:55.960 --> 0:11:57.800 get out of the field and make room for somebody 0:11:57.800 --> 0:12:00.560 who takes the job a little more seriously. That's interesting. 0:12:00.640 --> 0:12:02.719 I wonder if that also goes hand in hand with 0:12:03.400 --> 0:12:06.000 the open machines and them saying like, we don't need 0:12:06.120 --> 0:12:08.960 as much goss as we thought we did. I think 0:12:08.960 --> 0:12:10.880 it does. I think they're figuring out ways to get 0:12:10.880 --> 0:12:14.280 better resolution off lower power, because not only is it 0:12:14.600 --> 0:12:18.160 really expensive, I think it's a new machine costs about 0:12:18.160 --> 0:12:21.840 a million dollars per tesla it produces. So if you've 0:12:21.840 --> 0:12:25.320 got a ten ten tesla machine, which really at this point, 0:12:25.320 --> 0:12:27.040 from what I understand, is just showing off as a 0:12:27.080 --> 0:12:31.080 medical center. Um, you just spent ten million dollars on 0:12:31.160 --> 0:12:35.160 this one m r I machine in your medical center. Um. 0:12:35.200 --> 0:12:37.440 But that also it costs a lot of money to 0:12:37.600 --> 0:12:40.960 run one of these things because to keep this stable 0:12:41.040 --> 0:12:44.439 magnetic field going, you gotta run a lot of electricity 0:12:44.480 --> 0:12:48.000 through it. And that's where the super conductivity comes in. Yeah, 0:12:48.040 --> 0:12:50.320 I mean you want two rids. I mean you've got 0:12:50.400 --> 0:12:54.080 to have like zero resistance running through those wires. And 0:12:54.320 --> 0:12:56.559 they do this and I remember we talked about this 0:12:56.640 --> 0:12:59.920 in our Are we running out of Helium? I can't 0:13:00.000 --> 0:13:01.800 abo what it was called about. We did an episode 0:13:01.880 --> 0:13:05.040 on the fact that helium um was in short supply. 0:13:05.800 --> 0:13:08.040 And one of the downsides of this, it wasn't just 0:13:08.120 --> 0:13:12.360 birthday balloons, was the fact that they use helium liquid 0:13:12.400 --> 0:13:17.400 helium to uh to make these copper coils super conductive 0:13:17.559 --> 0:13:20.400 and I think at the order of about four hundred 0:13:20.440 --> 0:13:25.000 and fifty two degrees below zero. So without that helium, 0:13:25.000 --> 0:13:28.040 they don't know if they're looking at alternatives or if 0:13:28.080 --> 0:13:31.520 there's a Plan B or not, but they need helium. Well, 0:13:31.640 --> 0:13:34.200 remember in our Macy's Thanksgiving day preative. So I don't 0:13:34.200 --> 0:13:35.640 know if it made it in there or not, but 0:13:35.720 --> 0:13:39.600 they they found like a helium supply that basically like 0:13:39.920 --> 0:13:44.480 and Macy's bought it that basically like expanded our supply 0:13:44.520 --> 0:13:47.360 of helium by some infinite amounts. So we're like flush 0:13:47.400 --> 0:13:49.840 with helium. That's true. I remember that. So so I 0:13:49.840 --> 0:13:51.559 think we're okay. So we can just the cam was 0:13:51.640 --> 0:13:53.240 kicked down the road, Chuck. We don't need to worry 0:13:53.240 --> 0:13:55.959 about that. Yeah, we don't need a plan for the future, 0:13:56.400 --> 0:14:00.360 like Y two K right, it's exactly right. Nice, nice 0:14:00.400 --> 0:14:04.080 call out. All right, So you've got your big magnet um. 0:14:04.120 --> 0:14:08.480 You you also have gradient magnets. You have three gradient magnets, 0:14:08.559 --> 0:14:12.400 and those are not nearly as on the magnitude of 0:14:12.440 --> 0:14:15.160 that the big daddy. These are about one eighty to 0:14:15.280 --> 0:14:18.960 two seventy GAUSS. And your main magnet is what's creating 0:14:19.000 --> 0:14:21.280 that main magnetic field that we're gonna go over in 0:14:21.320 --> 0:14:24.200 detail in the second, the real stable one. But the 0:14:24.240 --> 0:14:28.280 other magnets create the variable field, which you know, that's 0:14:28.280 --> 0:14:32.760 what you need to run it um against the other 0:14:32.760 --> 0:14:36.640 one to make those images happen. Yeah, that's the that's 0:14:36.680 --> 0:14:42.320 basically what you use, like to direct the UM beam 0:14:42.480 --> 0:14:44.600 essentially as it were like if you need a shoulder 0:14:44.600 --> 0:14:46.680 looked at, it would be then a different location than 0:14:46.720 --> 0:14:49.800 your knee. Yeah yeah, And you would say, well, actually 0:14:49.840 --> 0:14:51.880 I needed a little to the left, and you would 0:14:51.920 --> 0:14:54.880 use these gradient magnets to move the magnetic field. And 0:14:54.920 --> 0:14:57.920 what you're really moving from what I understand with the 0:14:57.920 --> 0:15:02.960 gradient magnets is a radio free quency pulse. And this 0:15:03.000 --> 0:15:06.040 is this is where things this is where it all 0:15:06.160 --> 0:15:09.200 comes together. You're you're using three different things. Right, You've 0:15:09.240 --> 0:15:12.880 got the magnet and when you when you put um hydrogen, 0:15:12.960 --> 0:15:15.480 when you put a body, well, we're not quite there yet, 0:15:15.720 --> 0:15:19.480 I'll oh you want me to do it now? Well, 0:15:19.520 --> 0:15:23.000 I mean it certainly was anticipation on my part. Okay, 0:15:23.040 --> 0:15:25.720 all right, I won't let you down, Chuck. So when 0:15:25.800 --> 0:15:30.040 you go into the m R I bore and you 0:15:30.360 --> 0:15:33.000 enter this magnetic field the tube, I don't think we've 0:15:33.040 --> 0:15:36.640 mentioned that true. Um, When you go in the tube 0:15:37.200 --> 0:15:40.440 and you enter the magnetic field, the atoms in your 0:15:40.480 --> 0:15:44.840 body UM have what's called the magnetic moment, which means 0:15:44.880 --> 0:15:50.360 that they respond to very strong magnetic fields by abandoning 0:15:50.400 --> 0:15:54.040 their kind of random spin along their access their procession 0:15:55.040 --> 0:16:00.560 and snapping in line along the polar ends of the 0:16:00.600 --> 0:16:03.680 magnetic field. And in the m r I that that's 0:16:03.760 --> 0:16:06.120 running lengthwise down the middle. So if you're laying on 0:16:06.160 --> 0:16:08.360 your back in an m R I tube, the magnetic 0:16:08.360 --> 0:16:10.920 field is going from your feet to your head, and 0:16:10.960 --> 0:16:15.080 that magnetic field causes the atoms in your body or 0:16:15.120 --> 0:16:18.240 the particles in your body that make up atoms, to 0:16:18.440 --> 0:16:22.040 snap into line with that polarity. So all of a sudden, 0:16:22.080 --> 0:16:24.200 you have protons in this case, as far as the 0:16:24.280 --> 0:16:29.080 m R is concerned, hydrogen protons um suddenly going from 0:16:29.160 --> 0:16:33.200 random spins to all facing your feet are all spinning 0:16:33.200 --> 0:16:36.360 towards your head, one or the other, but technically along 0:16:36.400 --> 0:16:39.240 the same line. Yeah, So some of those are and 0:16:39.360 --> 0:16:42.680 I think in the biz they call it aligning parallel 0:16:43.360 --> 0:16:47.720 or anti parallel, and they sort of cancel each other out, 0:16:47.760 --> 0:16:52.760 but there's always going to be more parallel aligned hydrogen atoms, 0:16:53.280 --> 0:16:57.240 and those are the ones that uh, we're using to 0:16:57.280 --> 0:16:59.480 measure the m R I basically, like everything else, just 0:16:59.520 --> 0:17:01.920 sort of can't as each other out, and those leftover 0:17:02.000 --> 0:17:06.360 ones and it sounds, you know, there's there's so many 0:17:06.400 --> 0:17:09.600 that you can have the cancelation of many and it 0:17:09.720 --> 0:17:12.800 still works. So I only saw this in the House 0:17:12.840 --> 0:17:16.879 to Works article. Everywhere else I saw basically made no 0:17:16.960 --> 0:17:20.160 mention of the fact that, like whether they were aligned 0:17:20.200 --> 0:17:23.360 towards your feet or towards your head, like that that mattered, 0:17:23.400 --> 0:17:26.000 and that you were focusing on the ones that hadn't aligned, 0:17:26.640 --> 0:17:31.119 like I only saw it in this article. Oh you did, okay? 0:17:31.160 --> 0:17:35.040 So then kids Science, what is what? They were all 0:17:35.080 --> 0:17:37.399 based off this House of Works article? No? No, you 0:17:37.440 --> 0:17:40.440 could tell they were original? What is I was just teasing, 0:17:40.760 --> 0:17:44.199 you know, I love kids science websites. Chuck which when 0:17:44.240 --> 0:17:47.320 this one was? But it was a good one. Um, okay. 0:17:47.520 --> 0:17:51.480 So regardless of what which adams you're focusing on, either 0:17:51.560 --> 0:17:54.960 the ones that are polarized from along the magnetic field 0:17:55.000 --> 0:17:59.120 are the ones that haven't been polarized. That's that polarity 0:17:59.240 --> 0:18:02.880 is being created by the main magnet, the superconducting magnet 0:18:03.320 --> 0:18:06.520 that has basically zero resistance because it's bathed in liquid 0:18:06.600 --> 0:18:12.040 helium and cool to just astounding temperatures. Right now, when 0:18:12.080 --> 0:18:15.960 you bring in the radio frequency pulse, which is oscillating, 0:18:15.960 --> 0:18:19.880 it's turning on and off very very quickly. What what 0:18:19.920 --> 0:18:23.000 was discovered over the last century or so before m 0:18:23.119 --> 0:18:26.280 RIS wherever even developed. But what forms the basis of 0:18:26.320 --> 0:18:29.199 the principle that mrs operate on is that if you 0:18:29.240 --> 0:18:33.080 apply a radio frequency to a bunch of um of 0:18:33.320 --> 0:18:39.120 hydrogen protons undergoing their magnetic moment, you can actually adjust 0:18:40.000 --> 0:18:43.080 the way that they're aligned. You're kind of like pushing 0:18:43.200 --> 0:18:47.199 or pulling them out of alignment, and they're kind of 0:18:47.240 --> 0:18:50.560 struggling against it, but you can you can overcome that 0:18:50.880 --> 0:18:54.720 with the radio frequency pulse. And so that's basically step 0:18:54.840 --> 0:18:57.640 one of the m R I is getting them knocked 0:18:57.680 --> 0:19:00.520 out of that polarity so that you can turn that 0:19:00.600 --> 0:19:05.240 off and basically gauge and measure them as they snap 0:19:05.280 --> 0:19:08.800 back into that polarity. Yeah, and that radio frequency pulse 0:19:08.880 --> 0:19:13.120 it has to be the same frequency of those spinning protons, 0:19:13.800 --> 0:19:15.960 so if not, they're not going to be in resonance. 0:19:15.960 --> 0:19:18.600 That's where the word resonance comes from. If they have 0:19:18.720 --> 0:19:21.520 that same frequency, they can exchange energy with one another 0:19:21.960 --> 0:19:26.320 and they're on resonance with one another, and when they 0:19:26.359 --> 0:19:28.679 turn it on and off, like you said, there's a 0:19:28.760 --> 0:19:33.000 moment where they snap back into snap back to attention essentially, 0:19:33.600 --> 0:19:35.080 and it takes a little bit of time and a 0:19:35.080 --> 0:19:38.960 little bit of energy, and that energy is what they're 0:19:39.000 --> 0:19:45.240 basically trying to measure, like that, that movement. Yeah, and 0:19:45.680 --> 0:19:49.840 because the protons, the hydrogen protons. The reason they selected 0:19:49.920 --> 0:19:53.720 hydrogen protons is because it's so abundant throughout the body. Uh, 0:19:53.720 --> 0:19:56.080 it's far and away the most abundant atom in the 0:19:56.119 --> 0:19:59.960 body is hydrogen. Um. That that you're going to find 0:20:00.160 --> 0:20:03.800 in every bit, every every nook and cranny of your body. 0:20:03.880 --> 0:20:07.080 That's another term radiologist should stay away from, but we 0:20:07.119 --> 0:20:09.200 can use it. The nooks and crannies of your body 0:20:09.359 --> 0:20:14.159 all are filled with hydrogen protons. So um, they know 0:20:14.200 --> 0:20:17.600 that a hydrogen proton and like fat, tissue is going 0:20:17.640 --> 0:20:22.120 to snap back into place and then release energy at 0:20:22.119 --> 0:20:25.160 a slightly different frequency and at a slightly different rate 0:20:25.320 --> 0:20:27.879 than the hydrogen protons making up water in the body 0:20:27.960 --> 0:20:31.160 or bone in the body or you know, your hair 0:20:31.359 --> 0:20:34.280 on your shoulders or whatever. All all of this stuff 0:20:34.359 --> 0:20:37.640 is going to just be just slightly different. And they 0:20:37.680 --> 0:20:41.960 basically know what the data that comes back, what it's 0:20:42.000 --> 0:20:44.600 telling them is, Oh, hey, i'm a I'm a fat 0:20:44.800 --> 0:20:46.800 I'm in a bunch of fat over here. I'm into 0:20:46.840 --> 0:20:50.479 water over here, I'm shoulder hair over here. And this 0:20:50.560 --> 0:20:53.359 is the data that gets transmitted to the computer that's 0:20:53.400 --> 0:20:57.000 measured by the computer that's running the MR. Yeah, and 0:20:57.040 --> 0:21:00.800 that energy burst that it emits, it's at a very 0:21:00.840 --> 0:21:06.040 specific frequency named the lar More frequency after an Irish 0:21:06.119 --> 0:21:10.359 physicist named Sir Joseph Larmore. He discovered this all the 0:21:10.359 --> 0:21:14.720 way back in and you will never need to know 0:21:14.800 --> 0:21:16.879 this information, but just in case you want to know, 0:21:17.480 --> 0:21:21.040 the lar More frequency for hydrogen in this case is 0:21:21.080 --> 0:21:25.159 forty two point five eight mega hurts per tesla of 0:21:25.240 --> 0:21:29.760 magnetic force. That's a I don't even know if that's 0:21:29.760 --> 0:21:33.040 like a cocktail that that's not even a Jeopardy question. 0:21:34.640 --> 0:21:36.959 That's a dark little pet you keep in your pocket 0:21:37.000 --> 0:21:38.960 that you pull out and like stroke every once in 0:21:39.000 --> 0:21:42.160 a while. Just reassure yourself that you're very smart. Yeah, 0:21:42.240 --> 0:21:45.800 like LaVar Burton should be. LaVar Burton would ask that 0:21:45.880 --> 0:21:48.520 question on Jeopardy and Ken Jennings would say, you gotta 0:21:48.520 --> 0:21:53.760 be kidding me. Nobody cares love, so you're you're pulling 0:21:53.800 --> 0:21:55.879 for LaVar. He's not gonna make it. I mean the 0:21:55.880 --> 0:21:59.200 other guy that somehow the executive producer of the show 0:21:59.280 --> 0:22:03.679 is of naming himself. Yeah, I mean he said that 0:22:03.720 --> 0:22:06.160 he didn't make the call, but us, I don't know, man, 0:22:06.280 --> 0:22:08.600 he I thought LaVar Burton was great and would be 0:22:08.600 --> 0:22:12.360 great for that show. I'm part of team George Stefanopolis. 0:22:13.520 --> 0:22:17.080 Did he guess yeah? Or Aaron Rodgers. He did a 0:22:17.080 --> 0:22:19.600 good job. I didn't see that one, but he still 0:22:19.640 --> 0:22:21.840 got more football to play. I'm with you, though, I 0:22:21.840 --> 0:22:24.359 think LaVar Burton would be wonderful, and from what I read, 0:22:24.400 --> 0:22:27.440 he really wants it too. So I just don't get it. 0:22:27.640 --> 0:22:29.640 And a lot of people are mad already, so I'm 0:22:29.640 --> 0:22:32.720 not so so the decision has been made. It's the 0:22:32.760 --> 0:22:36.760 executive producer. Now. They said that they're in the final negotiations. 0:22:36.800 --> 0:22:39.399 And you know, now there are some people pointing to 0:22:39.440 --> 0:22:43.879 his past, because this guy's a experienced game show executive producer, 0:22:43.960 --> 0:22:46.360 and they're like, yeah, when you were on the Prices, right, 0:22:46.520 --> 0:22:50.040 you did some not so great things, and so we'll 0:22:50.040 --> 0:22:55.960 see what happens. I don't know, what a dusty old crotch. Oh, 0:22:56.119 --> 0:22:59.760 I don't know. We'll see what happens. Let's bring humility back, everybody. 0:23:00.080 --> 0:23:03.639 Just this and the small doses is fine. That's right. 0:23:03.880 --> 0:23:06.840 And this has been game show, so Chuck and Josh 0:23:07.480 --> 0:23:10.760 and speaking of go listen to our live game shows 0:23:10.800 --> 0:23:15.160 episode I think from Denver. That was really good. Uh 0:23:15.200 --> 0:23:19.480 do we do one on game shows? Oh? My, yes 0:23:19.520 --> 0:23:22.720 we did. That's a good one. All right. So where 0:23:22.760 --> 0:23:25.879 are we? We are at the lar more frequency. I 0:23:25.960 --> 0:23:28.280 guess the one thing we need to mention to you 0:23:28.320 --> 0:23:32.080 talked earlier about the gradient magnets UM being applied to 0:23:32.160 --> 0:23:35.160 very specific parts of the body. In the biz, they 0:23:35.200 --> 0:23:39.000 call those areas slices. So you can just get us 0:23:39.119 --> 0:23:40.800 if they if you hear someone and if you're going 0:23:40.840 --> 0:23:42.720 to get an m R and you're nervous and they 0:23:42.720 --> 0:23:45.959 say get a slice of the shoulder. There, you're not 0:23:46.040 --> 0:23:48.080 getting a slice. The whole point is that of an 0:23:48.160 --> 0:23:50.360