Speaker 1: Welcome to tech Stuff, a production of I Heart Radios
Speaker 1: How Stuff Works. Hey there, and welcome to tech Stuff.
Speaker 1: I'm your host, Jonathan Strickland. I'm an executive producer with
Speaker 1: iHeart Radio and I love all things tech and guys,
Speaker 1: I have been traveling all over the United States as
Speaker 1: part of another podcast I do called The Restless Ones.
Speaker 1: If you've not checked that out, you should definitely give
Speaker 1: it a listen. I talked to chief technology officers, chief
Speaker 1: information officers, chief data officers, these really super smart folks
Speaker 1: who are shaping the way technology affects business, which means,
Speaker 1: in turn, it affects us. That show has been fantastic
Speaker 1: and a lot of work. It's also meant that I've
Speaker 1: been traveling a ton, so unfortunately, because of that, I
Speaker 1: didn't really have the time to fully research and write
Speaker 1: and prepare an episode ready to go today. So we're
Speaker 1: going to listen to a classic episode of tech Stuff instead,
Speaker 1: because I would rather do that than present a rushed,
Speaker 1: jerky kind of episode where you listen to it and
Speaker 1: think he didn't even put forth any effort. I always
Speaker 1: want to give you the best I can, so don't worry.
Speaker 1: New episodes of tech Stuff are right around the corner.
Speaker 1: I just didn't have it in me to get one
Speaker 1: out for today. So we're going to look back on
Speaker 1: a classic. This classic episode originally published on January two
Speaker 1: thousand fourteen, and it's called How Ultrasound Works, And I
Speaker 1: sat down with Lauren Vogelbaum, who was my co host
Speaker 1: at the time, to really talk about ultrasonic technology and
Speaker 1: what it's used for. I hope you guys enjoy it.
Speaker 1: Take a listen. As it turns out, humans have a
Speaker 1: certain range of sounds that a typical human can hear.
Speaker 1: Keeping in mind that different people can hear different ranges.
Speaker 1: Some may be able to hear a larger range, some
Speaker 1: people like me are starting to lose some of that range,
Speaker 1: and some people are better at lower higher ranges. Sure,
Speaker 1: um that the average is about twenty to twenty thousand
Speaker 1: hurts at the low and high end, right, So beyond
Speaker 1: twenty thousand hurts, like usually significantly beyond twenty thousand hurts
Speaker 1: at those higher frequencies. We call that ultrasonic. Well, you
Speaker 1: don't quite get into ultrasonicum right away. I mean, I mean,
Speaker 1: you know you've still got a good audible range. I mean,
Speaker 1: like Bluga whales, for example, can hear up to some
Speaker 1: like a hundred and twenty thousand hurts, but that is
Speaker 1: still not ultrasonic. Well, the true ultrasonic that we're looking at,
Speaker 1: for at least the the technology we'll be talking about
Speaker 1: today is in the one to one point five million
Speaker 1: hurts or mega hurts range. So that's where we're getting
Speaker 1: to a point where you know, animals are not detecting
Speaker 1: this kind of sounded a pitch that's much higher than
Speaker 1: a frequency that's much higher frequency and pitch I'm using
Speaker 1: almost interchangeably, which is little dis misleading, but you get
Speaker 1: what I'm saying. So this is a technology it's very
Speaker 1: much based in some part on something that actual animals
Speaker 1: are using. Some animals are using, right yep. And so
Speaker 1: that's something you probably heard about whenever you've you heard
Speaker 1: about things like bats or dolphins or whales. They all
Speaker 1: use echolocation as either a primary way of figuring out
Speaker 1: what their environments like in the case of bats, or
Speaker 1: you know, one of the many senses that they rely
Speaker 1: upon to explore their environments. Right. Humans also use this
Speaker 1: in the form of sonar or I mean really technically
Speaker 1: radar because we're talking about electromagnetic waves and waves, so yeah,
Speaker 1: but some are specifically is so that is like a
Speaker 1: sonic wave. So uh. In fact, sonar was a very
Speaker 1: important development in our history because radar, as it turns out,
Speaker 1: was not the best thing to use for underwater because
Speaker 1: you have a tinuation of those waves and you could
Speaker 1: never be really sure that the signals you were getting
Speaker 1: back were really accurate. Sonar is a much more accurate
Speaker 1: means of determining where something is underwater and whether it's
Speaker 1: moving towards you or moving away. We'll talk about more
Speaker 1: of that as we get further into this podcast, because
Speaker 1: some of those basic principles really determine some pretty cool
Speaker 1: uses of ultrasonic technology. Yeah, all of all of that
Speaker 1: history really builds upon the terrific baby viewing devices that
Speaker 1: we know and love today. Um, although that is certainly
Speaker 1: not the only use for ultrasound, as we will also
Speaker 1: get into. Yeah, I have a favorite one that I'll
Speaker 1: mention at the end. So, and it's one that I've
Speaker 1: talked about before on tech stuff. But that's okay, I
Speaker 1: don't mind repeating myself. All of you listeners out there
Speaker 1: who've been around for a while, you know this, so
Speaker 1: I appreciate that you humor me. I'm glad that you
Speaker 1: know this about yourself. John. Well, you know it's you
Speaker 1: reach a certain age, you come to some truths. So first,
Speaker 1: before I even dive into the history of ultrasonic technology,
Speaker 1: I have to give a shout out to Dr Jim Sung.
Speaker 1: He has a presentation online called the History of Ultrasound
Speaker 1: and Technological Advances that gave me a lot of insight
Speaker 1: into the the the discoveries that led to ultrasonic technology.
Speaker 1: And that's where I drew a lot of this information.
Speaker 1: So big up to him, really really good, clear, yes,
Speaker 1: very very simple kind of presentation. I did, you know,
Speaker 1: augment that with extra research, but it was a great
Speaker 1: starting point. So in sevento that's where we have a
Speaker 1: fellow by the name of Lazaro Spaladzani who was observing
Speaker 1: the behavior of bats, and as he was observing their behavior,
Speaker 1: he began to hypothesize what it was that allowed bats
Speaker 1: to navigate through really dark terrain, being able to avoid things,
Speaker 1: being able to zero in on prey. And as he
Speaker 1: thought about it, he came up with this hypothesis that
Speaker 1: perhaps they were making these very high pitched noises that
Speaker 1: were not necessarily within the range of human hearing. You
Speaker 1: might be able to hear a few squeaks now and then,
Speaker 1: but that's about it. But that they were also uh,
Speaker 1: reacting to the echoes of those noises to owne in
Speaker 1: on things or to avoid obstacles, a right to find
Speaker 1: out how far away or possibly even how big an
Speaker 1: obstacle or a predator or a piece of prey would
Speaker 1: be away from them. Yeah, because if if you're if
Speaker 1: you're hearing an echo come back, but it's not nearly
Speaker 1: as powerful as the sound you put out your your
Speaker 1: The result might be, oh, that thing is close, but
Speaker 1: it's also small. If you get a lot of signal back,
Speaker 1: you're like, Okay, there's something with a lot of surface
Speaker 1: area that's not too far away, and perhaps I don't
Speaker 1: want to go in that direction anymore. So he kind of,
Speaker 1: you know, was the one to propose this hypothesis of echolocation.
Speaker 1: Now that's again one of those basic principles that we
Speaker 1: would build upon to get to ultrasonic technology. In eighteen
Speaker 1: twenty six, you have Jean Daniel Calladon who was performing
Speaker 1: a series of experiments using a bell like a church bell.
Speaker 1: It was actually a church bell that he put underwater.
Speaker 1: He had a another little lever that had a striker
Speaker 1: on the end of it to strike the bell. So
Speaker 1: if you I like to imagine as one of those
Speaker 1: you remember then the cartoons, the boxing glove that's on
Speaker 1: the like accordion type thing stretches out. That's essentially what
Speaker 1: I imagined this to be. I'm sure that's exactly what
Speaker 1: it was, not according to the illustration I saw, but
Speaker 1: those things are never accurate. So anyway, there's this bell
Speaker 1: that's underneath the water, and he has a striker under
Speaker 1: the water as well. And then about ten miles away,
Speaker 1: according to the illustration, there was a second person in
Speaker 1: a boat who had a tube that went down into
Speaker 1: the water and they would essentially put their ear to
Speaker 1: the tube to listen in like an ear earpiece and earphone, yes,
Speaker 1: so that they could you would amplify any sounds they
Speaker 1: could maybe you know, their and their job was to
Speaker 1: listen for the tone of the bell, and so uh
Speaker 1: he would call it on strikes the bell. The person
Speaker 1: in the other boat writes down exactly when they heard
Speaker 1: the tone, and the idea here was actually for call
Speaker 1: it on to show that the sound would travel at
Speaker 1: a different speed through water that it did through the air.
Speaker 1: This was just to demonstrate hypothesis that sound traveled at
Speaker 1: different speeds through different media, something that we know to
Speaker 1: be true now, right, And and in fact, it travels
Speaker 1: faster in water than it does the air. Yeah, So
Speaker 1: depending upon how tightly packed the molecules are and whatever
Speaker 1: it is that you're looking at, sound can travel much
Speaker 1: more quickly through some media than others. And it's because
Speaker 1: it's a very it's a physical media. It's not an
Speaker 1: electromagnetic it's actual physical molecules banging into each other. So
Speaker 1: if they're more tightly packed, they banging into each other
Speaker 1: much more quickly. So in that case he was able
Speaker 1: to show that it indeed does travel at different speeds.
Speaker 1: Knowing that it travels at different speeds is also very
Speaker 1: important for the very basics of ultrasonic technology, which is
Speaker 1: why we're talking about in the first place. So the
Speaker 1: eighty six, our next date is eighteen eighty. We're just
Speaker 1: just scorching through history along. This is where Pierre and
Speaker 1: Jacques Curi discover the piece of electric effect, which we
Speaker 1: have talked about quite a few times on tech stuff.
Speaker 1: All right, this is this winds up being useful in
Speaker 1: many applications. But so what is it? Okay, So certain
Speaker 1: types of material, like for example, quartz crystals have this
Speaker 1: this particular this particular feature where if you were to
Speaker 1: apply an electric charge to this material, it would vibrate,
Speaker 1: or if you apply a mechanical stress to this object,
Speaker 1: it will then create an electrical charge. It's this weird
Speaker 1: reaction of electricity and actual kinetic movement energy that you're
Speaker 1: gonna see between the two things. And in the case
Speaker 1: of quartz crystals, it's really really regular. You know, if
Speaker 1: you know the properties of the quartz crystal, you are
Speaker 1: good to go. You know that at a certain charge,
Speaker 1: it's always going to give off the same kind of vibration.
Speaker 1: So that's why quartz crystals are used in a lot
Speaker 1: of watches. It's actually the thing that helps keep time
Speaker 1: right right. It creates the movement in courts watch because
Speaker 1: it is so regular or so um, so predictable. Um.
Speaker 1: It also can it's used to create a spark in
Speaker 1: the kind of gas lighters that are used for for
Speaker 1: candles or cigarettes, and also um, you know, it's being
Speaker 1: talked about for energy harvesting kind of materials that are
Speaker 1: being that are in research today right and now. In
Speaker 1: the case of ultrasonic technology, this is important because the
Speaker 1: quartz crystals are the things in most ultrasonic transducers that
Speaker 1: are creating the vibrations that themselves are these high frequency
Speaker 1: sound waves. And with something as simple as electricity or
Speaker 1: relatively simple or you know, relatively technologically um possible to
Speaker 1: put into an instrument. So also they're very important for
Speaker 1: picking the signals back up as its out. Well, we'll
Speaker 1: talk more about that when we get into the actual
Speaker 1: how it works stuff, but all of this, you know,
Speaker 1: again plays into it. So nineteen fift you have Paul
Speaker 1: Langevin who invents the hydrophone, which again very important this
Speaker 1: in this case, it's essentially a microphone that can go
Speaker 1: into the water, uh and it relies on the piece
Speaker 1: of electric effect in order to pick up signals in
Speaker 1: the water. What's doing is it's detecting changes in pressure,
Speaker 1: which are you know, that's what you know, the sound
Speaker 1: that's moving through the water is changing the actual pressure
Speaker 1: that the this hydrophone detects. The pressure changes affect the
Speaker 1: quartz crystals inside the hydrophone, which then generates the electricity,
Speaker 1: which then goes to another device that again in turns
Speaker 1: and figure out yeah, or even converted back over into
Speaker 1: sound so that you can listen to what's going on underneath.
Speaker 1: He got the the inspiration to really work on this
Speaker 1: after something that happened in nineteen twelve, which was when
Speaker 1: Leonardo DiCaprio sank to the bombo of the ocean and
Speaker 1: froze to death, or more historically speaking, is when the
Speaker 1: Titanic sank. I thought, that's what I just said. Well, um,
Speaker 1: but yeah, yeah. The hydrophone was originally created in order
Speaker 1: to help detect icebergs and submarines in other large World
Speaker 1: War One and World War Two. It was really important.
Speaker 1: World War two is also really when Sonar I came
Speaker 1: to play. But before sonar it was really just listening
Speaker 1: for stuff that you think that should not be there
Speaker 1: and we need to get out of here. So ninety
Speaker 1: seven or right thereabouts, a man named Carl Dissick, who
Speaker 1: was a doctor with the University of Vienna, begins to
Speaker 1: work on using ultrasound as a means of diagnosing brain tumors. Now,
Speaker 1: at this time, ultrasonic technology was mostly being used in
Speaker 1: those those non applications exactly. But he thought, you know,
Speaker 1: this could probably tell you more about what's going on
Speaker 1: inside a person. The human brain is filled with water.
Speaker 1: Yeah I can, I mean essentially, yeah, I can totally
Speaker 1: figure out what's going on. Maybe if there's a tumor
Speaker 1: or something, I can detect it. Now, his approach is
Speaker 1: very different from what is used today. What we use
Speaker 1: today is a reflective technique where you send a signal
Speaker 1: through a person. It reflects off of various various stuff,
Speaker 1: will go into more detail in the second half and
Speaker 1: bounces back and then read out by a receiver in
Speaker 1: the instrument right exactly, and then a computer kind of
Speaker 1: puts all that data together to make it meaningful to you.
Speaker 1: He was actually thinking about setting up two different ultrasonic transducers,
Speaker 1: one on either side of your noggat and zapping straight
Speaker 1: through the brain. So he had a receiver on both
Speaker 1: sides and a transceiver on both sides, so you're sending
Speaker 1: signals simultaneously. And the idea was that he thought that
Speaker 1: the reflection would never be reliable enough for you to
Speaker 1: be able to have any sort of precise idea what's
Speaker 1: going on. Other people said that his particular techniques were
Speaker 1: um muddy, like it was creating too much noise because
Speaker 1: you had these two different sources going at it, and
Speaker 1: so signals right and right, some of it's reflected back,
Speaker 1: some of it keeps going through, and so there are
Speaker 1: people who said that the information you would get back
Speaker 1: from this particular method, uh was you know, not terribly reliable.
Speaker 1: Dust because it turns out would go on to be
Speaker 1: drafted into the Luftwaffe during World War Two and actually
Speaker 1: would become a doctor treating head wounds for German soldiers. Um.
Speaker 1: He would continue after the war to really be a
Speaker 1: proponent of ultrasonic technology being used in the medical field. However,
Speaker 1: he continued to say that he wanted the transmission effect
Speaker 1: was more important than the reflective effect. Uh. And ultimately
Speaker 1: some researchers at M I I T determined that the method
Speaker 1: that Dosik was using was creating all this noise I
Speaker 1: was talking about before, and it really wasn't reliable. So
Speaker 1: history would end up switching gears, going the different direction
Speaker 1: and still using ultrasonic technology, but in a different implementation
Speaker 1: than he did. Yeah, and and absolutely that pioneering kind
Speaker 1: of going like hey, human bodies are fill of liquid
Speaker 1: we can use this technology to look at them too. Yeah,
Speaker 1: it's pretty it's sound. It's not like it's ionizing radiation.
Speaker 1: It's not something that's gonna cause you some form of harm.
Speaker 1: It's it's a physical that. There are a couple of
Speaker 1: concerns that I've heard here and there about the ultrasonic
Speaker 1: waves interfering or or creating small bubbles or or various
Speaker 1: things like right, right, But it's not an ionizing radiation,
Speaker 1: which is the main difference between that and other imaging.
Speaker 1: Definitely better than X rays. Yes, uh so that's when
Speaker 1: Dr George Ludwig writes a paper describing the use of
Speaker 1: an ultrasonic device to diagnose skull stones, and in nineteen
Speaker 1: fifty one, doctors Wild and Neil began publishing studies on
Speaker 1: ultrasonic characteristics of benign versus malignant breast tumors, not intended
Speaker 1: as a detection tool actually, but rather as a diagnostic
Speaker 1: tool once a tumor had been found, so, in other words,
Speaker 1: to determine whether or not this tumor in fact is
Speaker 1: benign or malignant. Right. So, yeah, so this is after
Speaker 1: we've already established it there is a presence of a
Speaker 1: tumor nifty eight we got Dr Ian Donald, who I
Speaker 1: love his technical title, which was Professor of Midwifery at
Speaker 1: the University of Glasgow. Yeah, he pioneered O B G
Speaker 1: Y and ultrasound, which is what most of us think
Speaker 1: about when we think of ultrasound devices in medical fields.
Speaker 1: I think it's it's for the common lay person. That
Speaker 1: is the application in which we have seen and heard
Speaker 1: it used. Yeah, and it's it's certainly one that oh no,
Speaker 1: that was kind of sorry, didn't do it this time.
Speaker 1: So it's it's certainly the thing that we see all
Speaker 1: the time in movies and television. And you know, it's
Speaker 1: the sty it's that's the typical was in the hospital.
Speaker 1: This is the picture of the baby. It's also I
Speaker 1: mean I just recently saw one because my sisters have
Speaker 1: a lot of people are born it turns out, Yeah,
Speaker 1: and it's a very popular way of of imaging before.
Speaker 1: I mean, you know, especially and we'll we'll go into
Speaker 1: this a little bit more later, but you know, it's
Speaker 1: it's really terrific for figuring out what's going on with
Speaker 1: a baby without doing any kind of harm to the
Speaker 1: mother or the baby, right, right, You don't want anything
Speaker 1: that could potentially disrupt development or cause other complications. Uh.
Speaker 1: So skipping way ahead because obviously ultrasound by this time
Speaker 1: had been an established medical technology. It's also was used
Speaker 1: in other applications. Will talk a little bit about that later.
Speaker 1: Uh skipping way ahead, we get to a point where
Speaker 1: Daniel Liechtenstein pioneers a point of care long ultrasound in
Speaker 1: the ice see you and says that ultrasound is the
Speaker 1: real stethoscope. At this stage, we're talking about precision where uh,
Speaker 1: it was much greater than anything that desn't ever managed.
Speaker 1: It was something where you could actually get a really
Speaker 1: accurate look and in some cases a three dimensional look
Speaker 1: at what's going on inside a person without it being
Speaker 1: invasive or terribly invasive, because there are some there are
Speaker 1: some exceptions we'll talk about, yes, But but this is
Speaker 1: mostly thanks to advancements in computers in the digitization of
Speaker 1: ultrasound exactly. So we're gonna talk a lot more about
Speaker 1: how this actually works, what's really going on with this stuff.
Speaker 1: But before we get into that, let's take a quick
Speaker 1: break to thank our sponsor. Alright, so we're back. Let's
Speaker 1: talk about how ultrasonic technology actually works. You have to
Speaker 1: be able to have something that creates an ultrasonic signal,
Speaker 1: and it has to be able to pick up that
Speaker 1: ultrasonic signal, and then it has to be able to
Speaker 1: interpret the signal. So these are these are some important
Speaker 1: elements that again would only have been possible due to
Speaker 1: the work of the people we talked about in the
Speaker 1: first half. So, uh, your basic, your basic approach here.
Speaker 1: This is before I get into any of the actual
Speaker 1: Here's the technical stuff that's going on. Is you've got
Speaker 1: a device that sends the signal out which then encounters
Speaker 1: the various tissue barriers in a person's body for ultrasonic
Speaker 1: medical imaging anyway. So, UH, as it encounters these barriers,
Speaker 1: some of those ultrasonic waves are gonna bounce back. So
Speaker 1: the machine starts to collect the data of the material
Speaker 1: of the waves that bounce back, the intensity of those waves,
Speaker 1: and the length of time it took for them to
Speaker 1: go out and bounce back, give the idea of things
Speaker 1: like the depth and the nature of the tissue itself.
Speaker 1: The uh, some of the waves will continue to penetrate
Speaker 1: into the patient's body and then bounce off other boundaries.
Speaker 1: So these boundaries are things like boundaries between liquids and
Speaker 1: soft tissue, or soft tissue and hard tissue, so and
Speaker 1: oregon and bones, that kind of thing. And as the
Speaker 1: waves go and bounce back, we start to be able
Speaker 1: to look at that data and determine what kind of
Speaker 1: tissue it was going through, because because we know that
Speaker 1: that these sound waves travel at different speeds through different
Speaker 1: types of Yeah, exactly, So by knowing you know, if
Speaker 1: you know that sound travels at such and such a
Speaker 1: speed as it goes through bone, which we know, we
Speaker 1: do know, I mean, I don't know, if I don't,
Speaker 1: we don't personally know. But human kind knows people smarter
Speaker 1: than you know. You have that thing where you just
Speaker 1: trust that people smarter than you are working on the problem.
Speaker 1: In this case, it's true, so not so much working
Speaker 1: as much as have already completely figured out there charts
Speaker 1: that you can look at. So the computer, which we'll
Speaker 1: talk about in the second, takes all this data in
Speaker 1: and is able to analyze it and determine which waves
Speaker 1: were the ones that passed through liquid, which ones were
Speaker 1: the ones that passed through soft tissue, which ones passed
Speaker 1: through hard tissue, and then adding all that information together
Speaker 1: is able to create a picture that's been displayed on
Speaker 1: a display. It sends the information to a display so
Speaker 1: that you get essentially a virtual representation of whatever it
Speaker 1: is that's there. Typically it's two dimensional, so we'll talk
Speaker 1: a bit about three D. Uh ultra relatively new development,
Speaker 1: but it is certainly possible. But your traditional ultrasonic images
Speaker 1: are two dimensional. So it's kind of like a a
Speaker 1: side view or top down view, depending upon the angle
Speaker 1: that's being used and what you are specifically trying to image, right, So, uh,
Speaker 1: it's a really cool approach. Now. The parts that are
Speaker 1: on an ultrasonic machine include the transducer probra, which we've
Speaker 1: talked a little bit about. Right. This is the device
Speaker 1: that is sending and receiving the signals. That's got at
Speaker 1: least one quartz crystal in it. It may have multiple
Speaker 1: quartz crystals in it, and in fact, if it does
Speaker 1: have multiple quarts crystals, you can time the different crystals
Speaker 1: to file air at you send charges to them at
Speaker 1: different times because each one has its own independent circuit,
Speaker 1: and that allows you to quote unquote steer the ultrasonic
Speaker 1: beam and be able to get a lot more precision
Speaker 1: about what's going on. UM. But even if it only
Speaker 1: has one crystal, I can still send and then receive.
Speaker 1: So what's happening is you send an electrical charge to
Speaker 1: the crystal. The crystal vibrates at this incredibly high frequency,
Speaker 1: which creates this ultrasonic sound like one to one point
Speaker 1: five mega hurts. And you're talking about possibly millions of
Speaker 1: these and a millions of pulses in a single second.
Speaker 1: They go into the body and start to bounce off
Speaker 1: of stuff. When the sounds bounce back to the transducer probe,
Speaker 1: they hit the quartz crystal, which causes the quartz crystal
Speaker 1: to vibrate, which then causes the electric charge to emanate.
Speaker 1: So because of that piece of electric effect, it works
Speaker 1: both ways. The device picks up the electric charges and
Speaker 1: that's what it's able to use to interpret the actual
Speaker 1: data that is gathered and sent onto the computer. So
Speaker 1: the computer, it's a CPU is you know, it's a computer.
Speaker 1: It it processes data, crunches numbers, It follows specific rules
Speaker 1: that have been programmed in that take into account all
Speaker 1: the basic information that we understand about how sound travels.
Speaker 1: So that's how it's able to build the actual useful
Speaker 1: information and generates this image on the screen. Right. Then
Speaker 1: you also have controls, big surprise there, right, So the
Speaker 1: controls allow you to do things like you have a
Speaker 1: medical practitioner who's called an ultrasonographer. Um. So the ultrasonographer
Speaker 1: can adjust things like the amplitude of the ultrasonic waves,
Speaker 1: their frequency, the duration of the pulses that the transducer
Speaker 1: probe is creating. All right. That the precise frequency of
Speaker 1: the waves greatly affects the resolution of the resulting image.
Speaker 1: So this is really important, yes, it really is. It
Speaker 1: Also it will determine how far the pulses can penetrate.
Speaker 1: And on top of all those other things, you also
Speaker 1: have a storage medium of some sort you want to
Speaker 1: save this data. Obviously that might be on a disk,
Speaker 1: or it might be on a you know, just a
Speaker 1: hard drive or whatever. But it has to have some
Speaker 1: source storage medium and also probably straight to the cloud
Speaker 1: to the cloud, which is possible now, uh. And also
Speaker 1: a printer so that you can print out an image,
Speaker 1: especially in the case of babies. I think that it's
Speaker 1: it's used more often in that case than um, yeah,
Speaker 1: than than necessary, Like here's how your heart isn't working
Speaker 1: that I mean, maybe if you want to collect that
Speaker 1: sort of thing. Maybe you do, I'm not judging, but no,
Speaker 1: that's exactly. My sister showed me a picture from her ultrasound,
Speaker 1: so I got to see my niece or nephew early.
Speaker 1: So that's kind of cool. Um, And now you know
Speaker 1: the that's that's your basic parts of the ultrasonic device.
Speaker 1: Keeping in mind that other you know, more advanced ones
Speaker 1: may have other elements to them. But that's that's what
Speaker 1: is kind of the bare requirements for you to have
Speaker 1: an ultrasonic medical device. So the only other thing I
Speaker 1: need to mention is that those those transducer probes also
Speaker 1: tend to have some sort of absorbent material that will
Speaker 1: allow it to absorb any echoes that would come from
Speaker 1: the probe itself, because otherwise you would get right so,
Speaker 1: because you don't want the crystal to just start vibrating
Speaker 1: as soon as something bounces off the interior of the
Speaker 1: probe and comes right back at the crystal. So that's
Speaker 1: what the absorbent materials for. It's designed so that it'll
Speaker 1: try and direct there's actually an acoustic lens that directs
Speaker 1: the sound towards the patient's body. So that's the basics.
Speaker 1: But you know that we mentioned already there's a little
Speaker 1: bit more than just the basic display and imaging. There's
Speaker 1: this whole three dimensional approach. UM. So first of all,
Speaker 1: to get the unpleasant parts out. Not all ultrasound is noninvasive, right, UM,
Speaker 1: it's not always external that there is recent controversy about
Speaker 1: this UM in in abortion law. Oh I did not
Speaker 1: know this, right, Well, it's it's the trans transmational ultrasound
Speaker 1: in contests. So yeah, because because sometimes UM, for for
Speaker 1: for many applications, you're looking at something in the body
Speaker 1: that is not the most easily accessed from the outside.
Speaker 1: So by by inserting a probe with an ultrasound uh
Speaker 1: bit on the end into an orifice of one kind
Speaker 1: or another, UM, you can determine many things about many
Speaker 1: important internal organs. Yep. So this is uh you know,
Speaker 1: it's probably a little less glamorous and comfortable than your
Speaker 1: typical ultrasound, but it's very important and it's still in
Speaker 1: the grand scheme of things. Like you know, it's hard
Speaker 1: to say it's non invasive because you're talking about inserting
Speaker 1: something into an orifice, but surgery, exploratory surgery way more invasive.
Speaker 1: So it's you know, it's either way. There's some approaches
Speaker 1: now where you can actually create three dimensional images of
Speaker 1: stuff using ultrasound, and it's pretty much what you would expect.
Speaker 1: You're you're you're moving the uh, the device, the transducer probe,
Speaker 1: whether it's internal or external, and you're trying to get
Speaker 1: multiple different views of whatever it is you're imaging. So
Speaker 1: in the case of a baby, it would be the
Speaker 1: baby and you might have to have the patient shift
Speaker 1: around or in order to get angles. But yeah, the
Speaker 1: computer takes in all that data and then creates a
Speaker 1: three dimensional model of whatever it is it's that it's encountered,
Speaker 1: and then you can look at that on the screen.
Speaker 1: So this can be used in all sorts of medical approaches.
Speaker 1: And uh. One of the things that relies upon is
Speaker 1: another basic physical property that or universe sound waves, and
Speaker 1: that we talked about before. Actually it's of any real waves,
Speaker 1: the Doppler effect, right, the and that's the thing that
Speaker 1: that describes how waves change shape when they encounter moving objects. Yeah,
Speaker 1: so whether you whether the observer is moving or something
Speaker 1: is moving toward an observer, this affects the way sound
Speaker 1: sounds to us. That's the way we perceive sound. It
Speaker 1: also affects the waves themselves. So let's say to that
Speaker 1: Lauren is uh is screaming at a a single, constant,
Speaker 1: constant pitch, perfect pitch. But she is just screaming, and
Speaker 1: I'm running toward her, which is probably what's causing the screaming.
Speaker 1: To me, the pitch is going to sound higher in
Speaker 1: nature than someone who's standing right next to Lauren wondering
Speaker 1: why she's screaming, And for the person who's running away
Speaker 1: from Lauren, because that person knows when Lauren screams that's
Speaker 1: bad news. It sounds like it's a lower pitch. Now.
Speaker 1: That's because as I'm running towards Lauren, those waves of
Speaker 1: sun waves coming towards me are actually compressed, right, uh
Speaker 1: huh and uh. And as you would run away from
Speaker 1: a noise, the sound waves lengthen and therefore deepen in pitch. Yeah,
Speaker 1: So this Doppler effect, if you know what the Doppler
Speaker 1: effect is, and you're able to measure it properly, you
Speaker 1: can actually use that to your advantage to determine the
Speaker 1: location of a moving object, whether it's moving towards you
Speaker 1: or away. In this case, it's being used to help
Speaker 1: create that three dimensional model. Hey there, it's Jonathan from
Speaker 1: here to mention that we're going to take another quick
Speaker 1: break about ultrasonic technology and we'll be right back. The
Speaker 1: Doppler effect method is mainly used for very specific types
Speaker 1: of imaging. Not all three D imaging is using this.
Speaker 1: Mostly stuff where you want to measure something really subtle,
Speaker 1: like blood flow through veins right in in in early
Speaker 1: experiments with this and intravenous contrast agent would be introduced UM.
Speaker 1: But then as the method was honed, we've we've become
Speaker 1: able to detect movement of the blood cells themselves via
Speaker 1: change in pitch. That's pretty amazing and it's really useful.
Speaker 1: I mean it's for diseases that are largely invisible to us, right,
Speaker 1: oh right, right, anything vascular, you know, finding clots or
Speaker 1: monitoring flow and risky patients you know, like like after
Speaker 1: a stroke or a transplanter surgery, um, as well as
Speaker 1: finding cancerous tumors based on on the way that the
Speaker 1: blood flow is being affected by the tumor. It's pretty phenomenal.
Speaker 1: I mean, I really find the stuff truly amazing. So
Speaker 1: it really became possible only with the digital revolution of
Speaker 1: the nineteen eighties, like we were saying earlier. Um, because
Speaker 1: you know, computers made it possible to to a more
Speaker 1: precisely shape that ultrasonic beam as we as we mentioned,
Speaker 1: and and be two to use multiple beams from multiple
Speaker 1: angles simultaneously, which is that that multi courts action that
Speaker 1: we were talking about. And you're talking about an enormous
Speaker 1: amount of data, so it has to be a powerful
Speaker 1: computer just to crunch all the numbers properly. So as
Speaker 1: as those technologies have improved, so have the techniques. So
Speaker 1: let's talk a little bit about what would be like
Speaker 1: to go in and have to have an ultrasound procedure done.
Speaker 1: Because a lot of people I think I've only seen
Speaker 1: this on television shows or movies. Yeah, I if this
Speaker 1: isn't complete, t M I UM, I have actually had
Speaker 1: an ultrasound done. Um I. I go in for a
Speaker 1: mammogram every year, and in addition to the mammogram, they
Speaker 1: also do an ultrasound. All right, So so so tell
Speaker 1: me if I got any of this wrong, because I
Speaker 1: have not got in for an ultrasound. So, but I
Speaker 1: based it off a great article called how Ultrasound Works
Speaker 1: from how stuff Works dot com. Lug so typically what
Speaker 1: you have as a patient comes in and removes his
Speaker 1: or her clothing or whatever clothing would be in the
Speaker 1: way specifically of the ultrasound equipment. Sure, because you don't
Speaker 1: want to pick up the cloth. That wouldn't be useful, right,
Speaker 1: That would that would be that would corrupt the signal,
Speaker 1: So you would be that would make things more difficult. Also,
Speaker 1: it could end up just even if it didn't directly
Speaker 1: interrupt the signal, it could cause the probe to not
Speaker 1: be flu flush against the skin, which could cause problems
Speaker 1: right along those lines. Yeah, so we're getting into the jelly,
Speaker 1: aren't we, the mineral oil based jelly. You might wonder
Speaker 1: if you've ever seen essentially, but but if you've ever
Speaker 1: seen any other movies where they they're spreading the jelly
Speaker 1: over a patient's skin before using the ultrasound, you're wondering
Speaker 1: why it's so that they can seal up any air
Speaker 1: pockets that would have formed between the transducer probe and
Speaker 1: the skin of the patient. Right Because, like we've said before,
Speaker 1: since sound waves move differently through different media, when you've
Speaker 1: got air in the way, that's going to cause some problems. Right,
Speaker 1: So you don't want any air in the way. That's
Speaker 1: why the jellies used, so in case you were ever wondering,
Speaker 1: that's the purpose. Now at that point you have the
Speaker 1: machine sending through those ultrasonic signals through the patient and
Speaker 1: picking up the result through the probe through the patient exactly,
Speaker 1: and then those sounds are reflecting off of the various
Speaker 1: tissues within the patient coming back through the probe, sending
Speaker 1: those signals back to the CPU, which then interprets them
Speaker 1: and sends the signals to display which may or may
Speaker 1: not be in view of the patient, depending upon what
Speaker 1: the procedure is. Uh, and depending on you know, whether
Speaker 1: the patient is is conscious or whether they want to
Speaker 1: be looking at it UM and that the tech could
Speaker 1: at that point mark areas for further investigation UM if needed. Yep.
Speaker 1: And then that's information is usually recorded onto the storage
Speaker 1: media so that it could be part of the patient's record.
Speaker 1: And uh. Then that's the patient is pretty much allowed
Speaker 1: to well, they're they're cleaned up the jelly. Yes, yes,
Speaker 1: they give you a towel, so you clean yourself up
Speaker 1: and then you put your clothes on and that part
Speaker 1: of the examination is done. So it's pretty simple. In
Speaker 1: the grand scheme of things. It's like it's like we said,
Speaker 1: your basic ultrasonic uh investigation there is non invasive, so
Speaker 1: that's a good thing. UM. Now, beyond the diagnoses, they're
Speaker 1: actually looking at using ultrasonic technology to do some treatments.
Speaker 1: So it's not just a a tool that's used to
Speaker 1: check up on someone or get another look at something
Speaker 1: that may or may not be a problem. In some cases,
Speaker 1: they're talking about using it to to treat medical conditions,
Speaker 1: often with nanotechnology. Although one of the coolest ones I
Speaker 1: read about recently is another diagnostic tool, not a medical
Speaker 1: treatment tool. It's a nano device that's an a nano
Speaker 1: sized ultrasonic transducer that can actually image the interior of
Speaker 1: a cell, individual living cell. That's awesome. Yeah, it's pretty
Speaker 1: neat when you get that precise. That's pretty phenomenal. Uh. Yeah.
Speaker 1: We we talked in a previous episode are are one
Speaker 1: about gene therapy from December a little bit about one
Speaker 1: of the other applications UM, which is using using ultrasound
Speaker 1: waves to UM to push a little kind of nano
Speaker 1: bubbles of of either medication or genes or whatever you
Speaker 1: want to get inside a cell over to to where
Speaker 1: you want them and then also using that ultrasound wave
Speaker 1: to burst them appropriate. So that becomes a method of
Speaker 1: delivery where you're actually maneuvering medication to some specific location.
Speaker 1: Which that that's seems to be the big approach right now,
Speaker 1: using ultrasonic or other technologies that are externally applied to
Speaker 1: get nano based medicines to the right location, because we
Speaker 1: haven't reached a point yet where we have little like
Speaker 1: nano sized spaceships that can go straight to where they
Speaker 1: need to go and then deliver the medical payload. So
Speaker 1: a lot of the actual controls are not because we've
Speaker 1: talked about nano robots before, this idea of a autonomous
Speaker 1: or even semi just semi autonomous machine that can move
Speaker 1: through the body. We are not there yet. But what
Speaker 1: we can do is create nano sized particles that can
Speaker 1: be manipulated externally through things like ultrasonic frequencies, which is
Speaker 1: kind of cool. And you know, speaking of using ultrasonic
Speaker 1: technology in fun ways, here's a fun way that ultrasonic
Speaker 1: technology used to be used. So back in the seventies, Lauren,
Speaker 1: there used to be an era called the nineteen seventies.
Speaker 1: I do not remember that era because I was not
Speaker 1: born yet, I was alive during this era. So in
Speaker 1: the early nineteen seventies, a lot of televisions that were
Speaker 1: coming out that had remote controls. Often not always, but
Speaker 1: often would use ultrasonic frequencies to be the signals that
Speaker 1: would send it to the television so that you could
Speaker 1: turn it on or off, or the volume or changing
Speaker 1: channel or whatever. So you would push a button and
Speaker 1: often it was just on or off like that was
Speaker 1: sometimes the only control that you had. Oh sure, I
Speaker 1: mean we we didn't have channels in those days anyways,
Speaker 1: as is usually about you know, between you'd have the
Speaker 1: channels two through thirteen in the new UHF channel. Anyway,
Speaker 1: you could turn the set on or off using this device.
Speaker 1: It would send us ultrasonic frequency that you could not hear,
Speaker 1: but it would be picked up by the television and
Speaker 1: it would do whatever it was supposed to do. The
Speaker 1: fun thing was that you could actually trigger this accidentally
Speaker 1: if you were messing around with something else, like I
Speaker 1: had uh an uncle who talked about how um he
Speaker 1: thought it was amazing when he accidentally turned off the
Speaker 1: television because he was carrying um a a like a
Speaker 1: container of nuts. And bolts. He was going to do
Speaker 1: a project, and he tripped and dropped them and they
Speaker 1: hit the tiled floor and the and some of them
Speaker 1: must have created this ultrasonic frequency that was the exact
Speaker 1: same frequency that teld the TV to turn off. And
Speaker 1: so he was wondering what was wrong with this television
Speaker 1: And it wasn't until you know, some further experimentation that
Speaker 1: he figured out, Oh so sound, Chris Pallette, the he
Speaker 1: used to change the channel or turn this television off
Speaker 1: by playing with a slinky. So um, yeah, fun times.
Speaker 1: Now these days, kids, uh, they're using either infrared or
Speaker 1: WiFi signals or some crazy thing like that. So you
Speaker 1: can play with a slinky all day along in front
Speaker 1: of your television and nothing's going to happen unless you
Speaker 1: happen to have a infrared slinking or a mischievous sibling
Speaker 1: with a remote control who is like, wow, look at
Speaker 1: what you're doing, which could either be really funny or
Speaker 1: you know, build you up for a terrible letdown later.
Speaker 1: Ultrasound can also be used to keep your car windshield clean.
Speaker 1: Say what seriously, the vibrations bounce, rain, debreathe like bugs, whatever,
Speaker 1: right off of your of your windshield. Um. There's a
Speaker 1: high end British car company called McLaren that is looking
Speaker 1: to bring this tech to consumer cars. UM, assuming that
Speaker 1: your consumer with you know, over two hundred thousand dollars.
Speaker 1: That wraps up this classic episode of tech Stuff about
Speaker 1: how ultrasound works. It's a fascinating technology, something that it
Speaker 1: The more I looked into it, the more I was surprised.
Speaker 1: This idea of using actual frequencies of sound in order
Speaker 1: to learn more about stuff like what's going on inside us,
Speaker 1: for example, beyond all the other applications. So it's a
Speaker 1: phenomenal use of technology and physics, something that I truly
Speaker 1: find fascinating. I hope you guys enjoyed this retrospective look
Speaker 1: back at a historic tech Stuff episode. We'll be back
Speaker 1: with new episodes next week. Can't wait to talk to
Speaker 1: you then. If you guys have suggestions for future episodes
Speaker 1: of tech Stuff, reach out on social media. You can
Speaker 1: find us on both Facebook and Twitter. We have the
Speaker 1: handle text stuff h s W and I'll talk to
Speaker 1: you again really soon. Text Stuff is a production of
Speaker 1: I Heeart Radio's How Stuff Works. For more podcasts from
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Speaker 1: or ever you listen to your favorite shows.