How we can use light to see deep inside our bodies and brains | Mary Lou Jepsen

9 min read
Transcript 0:12 People don’t realize 0:14 that red light and benign near-infrared light 0:18 go...

Transcript

0:12
People don’t realize
0:14
that red light and benign near-infrared light
0:18
go right through your hand, just like this.
0:23
This fact could enable better, faster and cheaper health care.
0:28
Our translucence is key here.
0:32
I’m going to show you how we use this key and a couple of other keys
0:35
to see deep inside our bodies and brains.
0:40
OK, so first up …
0:42
You see this laser pointer and the spot it makes on my hand?
0:47
The light goes right through my hand —
0:49
if we could bring the lights down, please —
0:51
as I’ve already shown.
0:52
But you can no longer see that laser spot.
0:55
You see my hand glow.
0:58
That’s because the light spreads out, it scatters.
1:02
I need you to understand what scattering is,
1:05
so I can show you how we get rid of it
1:08
and see deep inside our bodies and brains.
1:12
So, I’ve got a piece of chicken back here.
1:15
(Laughter)
1:17
It’s raw.
1:20
Putting on some gloves.
1:21
It’s got the same optical properties as human flesh.
1:29
So, here’s the chicken … putting it on the light.
1:34
Can you see, the light goes right through?
1:38
I also implanted a tumor in that chicken.
1:42
Can you see it?
1:43
Audience: Yes.
1:44
Mary Lou Jepsen: So this means, using red light and infrared light,
1:49
we can see tumors in human flesh.
1:53
But there’s a catch.
1:55
When I throw another piece of chicken on it,
1:59
the light still goes through,
2:02
but you can no longer see the tumor.
2:05
That’s because the light scatters.
2:08
So we have to do something about the scatter
2:10
so we can see the tumor.
2:14
We have to de-scatter the light.
2:17
So …
2:19
A technology I spent the early part of my career on
2:22
enables de-scattering.
2:24
It’s called holography.
2:26
And it won the Nobel Prize in physics in the 70s,
2:29
because of the fantastic things it enables you to do with light.
2:34
This is a hologram.
2:36
It captures all of the light, all of the rays, all of the photons
2:41
at all of the positions and all of the angles, simultaneously.
2:47
It’s amazing.
2:48
To see what we can do with holography …
2:53
You see these marbles?
2:54
Look at these marbles bouncing off of the barriers,
2:57
as an analogy to light being scattered by our bodies.
3:02
As the marbles get to the bottom of the scattering maze,
3:06
they’re chaotic, they’re scattering and bouncing everywhere.
3:11
If we record a hologram at the bottom inside of the screen,
3:15
we can record the position and angle of each marble exiting the maze.
3:22
And then we can bring in marbles from below
3:26
and have the hologram direct each marble to exactly the right position and angle,
3:32
such as they emerge in a line at the top of the scatter matrix.
3:39
We’re going to do that with this.
3:41
This is optically similar to human brain.
3:46
I’m going to switch to green light now,
3:49
because green light is brighter to your eyes than red or infrared,
3:53
and I really need you to see this.
3:55
So we’re going to put a hologram in front of this brain
4:00
and make a stream of light come out of it.
4:04
Seems impossible but it isn’t.
4:07
This is the setup you’re going to see.
4:10
Green light.
4:12
Hologram here, green light going in,
4:15
that’s our brain.
4:18
And a stream of light comes out of it.
4:22
We just made a brain lase of densely scattering tissue.
4:27
Seems impossible, no one’s done this before,
4:30
you’re the first public audience to ever see this.
4:33
(Applause)
4:38
What this means is that we can focus deep into tissue.
4:42
Our translucency is the first key.
4:45
Holography enabling de-scattering is the second key
4:49
to enable us to see deep inside of our bodies and brains.
4:54
You’re probably thinking,
4:57
“Sounds good, but what about skull and bones?
5:00
How are you going to see through the brain without seeing through bone?”
5:04
Well, this is real human skull.
5:07
We ordered it at skullsunlimited.com.
5:10
(Laughter)
5:12
No kidding.
5:13
But we treat this skull with great respect at our lab and here at TED.
5:18
And as you can see,
5:20
the red light goes right through it.
5:23
Goes through our bones.
5:25
So we can go through skull and bones and flesh with just red light.
5:31
Gamma rays and X-rays do that, too, but they cause tumors.
5:35
Red light is all around us.
5:39
So, using that, I’m going to come back here
5:42
and show you something more useful than making a brain lase.
5:46
We challenged ourselves to see how fine we could focus through brain tissue.
5:50
Focusing through this brain,
5:53
it was such a fine focus, we put a bare camera die in front of it.
5:58
And the bare camera die …
6:03
Could you turn down the spotlight?
6:05
OK, there it is.
6:07
Do you see that?
6:08
Each pixel is two-thousandths of a millimeter wide.
6:13
Two microns.
6:15
That means that spot focus — full width half max —
6:18
is six to eight microns.
6:21
To give you an idea of what that means:
6:24
that’s the diameter of the smallest neuron in the human brain.
6:29
So that means we can focus through skull and brain to a neuron.
6:34
No one has seen this before, we’re doing this for the first time here.
6:38
It’s not impossible.
6:39
(Applause)
6:41
We made it work with our system, so we’ve made a breakthrough.
6:44
(Laughter)
6:46
Just to give an idea — like, that’s not just 50 marbles.
6:49
That’s billions, trillion of photons,
6:52
all falling in line as directed by the hologram,
6:55
to ricochet through densely scattering brain,
7:01
and emerge as a focus.
7:03
It’s pretty cool.
7:06
We’re excited about it.
7:07
This is an MRI machine.
7:09
It’s a few million dollars, it fills a room,
7:11
many people have probably been in one.
7:14
I’ve spent a lot of time in one.
7:15
It has a focus of about a millimeter —
7:18
kind of chunky, compared to what I just showed you.
7:21
A system based on our technology could enable dramatically lower cost,
7:26
higher resolution
7:28
and smaller medical imaging.
7:31
So that’s what we’ve started to do.
7:34
My team and I have built a rig, a lab rig
7:38
to scan out tissue.
7:40
And here it is in action.
7:42
We wanted to see how good we could do.
7:46
We’ve built this over the last year.
7:49
And the result is,
7:51
we’re able to find tumors
7:56
in this sample —
7:57
70 millimeters deep, the light going in here,
8:00
half a millimeter resolution,
8:02
and that’s the tumor it found.
8:05
You’re probably looking at this,
8:08
like, “Sounds good, but that’s kind of a big system.
8:13
It’s smaller than a honking-big MRI machine,
8:17
monster MRI machine,
8:18
but can you do something to shrink it down?”
8:22
And the answer is:
8:23
of course.
8:25
We can replace each big element in that system
8:28
with a smaller component —
8:30
a little integrated circuit,
8:32
a display chip the size of a child’s fingernail.
8:37
A bit about my background:
8:39
I’ve spent the last two decades inventing, prototype-developing
8:45
and then shipping billions of dollars of consumer electronics —
8:50
with full custom chips —
8:52
on the hairy edge of optical physics.
8:55
So my team and I built the big lab rig
9:00
to perfect our architecture and test the corner cases
9:05
and really fine-tune our chip designs,
9:08
before spending the millions of dollars to fabricate each chip.
9:12
Our new chip inventions slim down the system, speed it up
9:17
and enable rapid scanning and de-scattering of light
9:21
to see deep into our bodies.
9:23
This is the third key to enable better, faster and cheaper health care.
9:33
This is a mock-up of something that can replace the functionality
9:40
of a multimillion-dollar MRI machine
9:43
into a consumer electronics price point,
9:46
that you could wear as a bandage, line a ski hat, put inside a pillow.
9:51
That’s what we’re building.
9:53
(Applause)
9:54
Oh, thanks!
9:56
(Applause)
9:59
So you’re probably thinking,
10:01
“I get the light going through our bodies.
10:04
I even get the holography de-scattering the light.
10:08
But how do we use these new chip inventions, exactly,
10:11
to do the scanning?”
10:13
Well, we have a sound approach.
10:16
No, literally — we use sound.
10:18
Here, these three discs represent the integrated circuits
10:23
that we’ve designed,
10:24
that massively reduce the size of our current bulky system.
10:30
One of the spots, one of the chips, emits a sonic ping,
10:34
and it focuses down,
10:36
and then we turn red light on.
10:39
And the red light that goes through that sonic spot
10:42
changes color slightly,
10:45
much like the pitch of the police car siren changes
10:48
as it speeds past you.
10:52
So.
10:53
There’s this other thing about holography I haven’t told you yet,
10:56
that you need to know.
10:58
Only two beams of exactly the same color can make a hologram.
11:03
So, that’s the orange light that’s coming off of the sonic spot,
11:09
that’s changed color slightly,
11:11
and we create a glowing disc of orange light
11:15
underneath a neighboring chip
11:17
and then record a hologram on the camera chip.
11:21
Like so.
11:22
From that hologram, we can extract information just about that sonic spot,
11:27
because we filter out all of the red light.
11:32
Then, we can optionally focus the light back down into the brain
11:35
to stimulate a neuron or part of the brain.
11:39
And then we move on to shift the sonic focus to another spot.
11:44
And that way, spot by spot, we scan out the brain.
11:49
Our chips decode holograms
11:51
a bit like Rosalind Franklin decoded this iconic image of X-ray diffraction
11:57
to reveal the structure of DNA for the first time.
12:01
We’re doing that electronically with our chips,
12:04
recording the image and decoding the information,
12:08
in a millionth of a second.
12:10
We scan fast.
12:13
Our system may be extraordinary at finding blood.
12:17
And that’s because blood absorbs red light and infrared light.
12:21
Blood is red.
12:23
Here’s a beaker of blood.
12:25
I’m going to show you.
12:27
And here’s our laser, going right through it.
12:31
It really is a laser, you can see it on the — there it is.
12:34
In comparison to my pound of flesh,
12:38
where you can see the light goes everywhere.
12:41
So let’s see that again, blood.
12:44
This is really key: blood absorbs light,
12:47
flesh scatters light.
12:51
This is significant,
12:52
because every tumor bigger than a cubic millimeter or two
12:56
has five times the amount of blood as normal flesh.
13:01
So with our system, you can imagine detecting cancers early,
13:05
when intervention is easy,
13:07
or tracking the size of your tumor as it grows or shrinks.
13:12
Our system also should be extraordinary at finding out where blood isn’t,
13:17
like a clogged artery,
13:19
or the color change in blood
13:21
as it carries oxygen versus not carrying oxygen,
13:24
which is a way to measure neural activity.
13:28
There’s a saying that “sunlight” is the best disinfectant.
13:33
It’s literally true.
13:35
Researchers are killing pneumonia in lungs by shining light deep inside of lungs.
13:41
Our system could enable this noninvasively.
13:45
Let me give you three more examples of what this technology can do.
13:50
One: stroke.
13:52
There’s two major kinds of stroke:
13:54
the one caused by clogs
13:57
and another caused by rupture.
13:59
If you can determine the type of stroke within an hour or two,
14:03
you can give medication to massively reduce the damage to the brain.
14:08
Get the drug wrong,
14:10
and the patient dies.
14:12
Today, that means access to an MRI scanner within an hour or two of a stroke.
14:18
Tomorrow, with compact, portable, inexpensive imaging,
14:22
every ambulance and every clinic can decode the type of stroke
14:26
and get the right therapy on time.
14:30
(Applause)
14:34
Thanks.
14:36
Two:
14:38
two-thirds of humanity lacks access to medical imaging.
14:43
Compact, portable, inexpensive medical imaging can save countless lives.
14:49
And three:
14:50
brain-computer communication.
14:53
I’ve shown here onstage our system focusing through skull and brain
14:57
to the diameter of the smallest neuron.
15:01
Using light and sound, you can activate or inhibit neurons,
15:05
and simultaneously, we can match spec by spec
15:09
the resolution of an fMRI scanner,
15:11
which measures oxygen use in the brain.
15:14
We do that by looking at the color change in the blood,
15:17
rather than using a two-ton magnet.
15:21
So you can imagine that with fMRI scanners today,
15:28
we can decode the imagined words, images and dreams of those being scanned.
15:33
We’re working on a system that puts all three of these capabilities
15:37
into the same system —
15:38
neural read and write with light and sound,
15:41
while simultaneously mapping oxygen use in the brain —
15:45
all together in a noninvasive portable
15:48
that can enable brain-computer communication,
15:51
no implants, no surgery, no optional brain surgery required.
15:56
This can do enormous good
15:58
for the two billion people that suffer globally with brain disease.
16:04
(Applause)
16:09
People ask me how deep we can go.
16:11
And the answer is: the whole body’s in reach.
16:14
But here’s another way to look at it.
16:20
(Laughter)
16:22
My whole head just lit up, you want to see it again?
16:24
Audience: Yes!
16:26
(Laughter)
16:28
MLJ: This looks scary, but it’s not.
16:31
What’s truly scary is not knowing about our bodies,
16:34
our brains and our diseases
16:36
so we can effectively treat them.
16:38
This technology can help.
16:39
Thank you.
16:40
(Applause)
16:46
Thank you.
16:47
(Applause)

Leave a Reply

Your email address will not be published. Required fields are marked *