Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:08):
Particle physicists love playing with big, expensive toys. The large
Hadron collider in Switzerland costs more than ten billion dollars,
and hey, what is it good for? Well, you know,
understanding the nature of the universe and revealing the fundamental
properties of matter, energy, space, and time. It's a pretty
good deal if you ask me. But it's not just that.
(00:31):
Basic research has also created lots of technology that improves
our lives, including all of the electronics you're currently using
to listen to me on this podcast. But particle physics
has more directly saved lives as well. Usually we think
of particles as dangerous of radiation as a cause of cancer,
but what if particle physicists could do something useful for
(00:53):
Once Today on the pod, we'll be asking what if
particle beams could be used to treat cancer. Welcome to
Daniel and Kelly's Extraordinary Practical Universe.
Speaker 2 (01:18):
Hello.
Speaker 3 (01:18):
I'm Kelly Winersmith. I study parasites and space and I'm
excited to be talking about newer ish treatments for cancer today.
Speaker 4 (01:25):
Hi.
Speaker 1 (01:25):
I'm Daniel. I'm a particle physicist and I didn't get
into it to save anybody's life, but I'm happy if
it does.
Speaker 3 (01:32):
Yeah, today we're talking about a practical application of your work. Amazing, amazing,
And so I know that for some kinds of mathematicians,
if it turns out that their basic research has applications,
they're like almost bummed out because it makes it less pure.
How does the particle physics community feel about this amazing
(01:55):
application of their work?
Speaker 1 (01:56):
The broader community, I think is positive because they're always
looking for way to sell fundamental science to politicians and
to the general public that don't understand that, like any
investment in basic science is a good idea because it's
going to yield something in the long term, and they're
looking for something in the short term to use as
an example. For me personally, it's a bit more mixed.
(02:17):
I got into particle physics because it has almost no
immediate applications because, as you know, my parents worked in
the weapons program, and I was like, it's a little
morally complicated to be building weapons of mass destruction pointed
at civilian populations, which is basically what they were doing,
and so I was glad that there were no immediate applications.
So the idea that you're now building particle beams and
(02:39):
pointing them at people. I'm glad that that's a positive thing.
So I can imagine how there might be other uses
for high intensity particle beams pointed at people's headsikes. So yeah,
I think I would just prefer if the applications were
more downstream so I didn't have to think about it.
Speaker 3 (02:54):
Oh you feel like at some point they're downstream enough
that you don't have to worry. What if somebody tomorrow
I did say, Okay, this particle beam stuff results in
weapons of mass destruction, but it's twenty steps away. Does
that absolve you?
Speaker 1 (03:09):
As long as it's like, you know, twenty generations and
I'm dead when they build the torment nexus from all
of my particle physics work, then I think it's not
really my fault. What can I do about it?
Speaker 4 (03:19):
All?
Speaker 3 (03:19):
Right? Fair enough? Yeah, I guess you can't see the
implications generations down the line in some cases.
Speaker 1 (03:24):
But I do, in general think it's a really interesting
philosophical and moral quanity, because the only way to prevent
people from using ideas to build things to torture people
is to have no ideas and to make no advances.
And I think that's ridiculous, and so I think we
have to take leaps forward into the future and understand
the universe, knowing that it's going to change society. We
(03:44):
just hope for the better.
Speaker 3 (03:45):
Yeah, I totally agree, and so trying to think about
how we unroll these new technologies without having too many
negative implications, I soonish got me thinking about this topic
a lot, and I feel like we need to be
having a lot more conversations about how these technologies could
be used. But on the plus side, we don't have
to dig into too much of that today because this
is an unmitigated good.
Speaker 1 (04:07):
Yes, exactly, all of those taxpayer dollars spent on building
particle colliders have resulted in saving people's lives by curing
their cancers, and so today on the podcast we'd be
talking about exactly that topic. How exactly can you use
Daniel's ridiculously abstract research with his ten thousand friends to
(04:27):
cure cancer.
Speaker 3 (04:28):
I love that you have so many friends, Daniel. That's fantastic.
You're very likable, though I'm not surprised.
Speaker 1 (04:33):
Well, I'm rounding them all up to friends. I'm sure
there's some haters in that community.
Speaker 3 (04:37):
Oh, I say, yeah, I've got that too.
Speaker 1 (04:39):
So I went out there and asked our audience if
they had an idea for how particle beams could be
used to treat cancer, and we're very delighted to have
their extemporing the speculation here on the podcast for you
to enjoy. If you would like to contribute for future episodes,
please don't be shy, write to us two questions at
danieland Kelly dot org. Here's what people had to say.
(05:01):
Particle beams are shot into the cancer at high speeds
and just shake it up from the inside out until
there's nothing left. Directed with magnets would focus on the cancer,
target the specific cancer cells.
Speaker 2 (05:17):
Radiation treatments which basically kill the cancerous cells.
Speaker 1 (05:22):
Through very finely targeted obliteration. Using a high energy particle beam,
you can destroy the cells in a very targeted way.
It just deteriorates the cell growth.
Speaker 3 (05:33):
Particle beams disrupting the DAYNI of the particular cancer cells.
Speaker 1 (05:38):
Zapping a location a cancer with political beam.
Speaker 2 (05:45):
The beams heat the cancer and stops it from metastasizing.
Speaker 4 (05:49):
So picking up on context clues here, it's got beam
in the name, and I'm pretty sure the main way
cancer is treated is by destroying cancer cells. So my
answer is via destruction of some kind from all different directions,
so that those beams all intersect in the exact shape
of the tumor, fry the area.
Speaker 1 (06:08):
The particles in the beam are specifically targeted at the
areas in which the cancer is.
Speaker 2 (06:16):
My energy protos immitted from a cyco latron go through
a lens that is shaped like the patient's tumor, so
that it goes no deeper than the.
Speaker 1 (06:27):
Tumor, focused on the cancer cells directly, so that they'll
form a constructive interference.
Speaker 3 (06:35):
Concentrated focused therapeutic particle beams directed at solid tumors reduce
their viability. The particles damage the Maligan cells DNA.
Speaker 2 (06:43):
The high energy in the gamma range damages their DNA,
so they can't replicate themselves anymore.
Speaker 1 (06:47):
I would think, by killing everything in their way, and
thereby also killing the cancer.
Speaker 3 (06:53):
These are super fantastic answers. It sounds like a lot
of people have heard of this before and so sort
of on the periphery of their knowledge. At least, I
hadn't heard about this until there was a case of
cancer in my family where we were thinking about this
as a treatment. Everything turned out okay. My sense is
that this isn't in the public consciousness aside from people
(07:15):
who have to think about this sort of treatment. But
maybe I'm wrong, because it does seem like almost everybody
had an answer that was like kind of on target.
Speaker 1 (07:23):
I think I knew roughly how this works, you know.
I knew that when you get cancer, your options are
like chemotherapy drinking poison basically, or radiation shooting particles at it,
or surgery trying to cut it out. In all cases,
they're like versions of localized suicide, like let's try to
kill this part of my body before it kills the
(07:43):
rest of me. Yeah, But until a couple of friends
had weird growths in their brains recently and it really
had to make this decision, radiation or surgery never really
dug into the details the physics of like how does
a particle beam hurt a tumor how do you aim it,
how do you make sure you get to the right spot,
what kind of particle should you use? So I thought
(08:04):
it'd be really valuable for people to have some sort
of understanding of this, so that in the moment when
they're faced with these decisions, maybe they have some understanding
of these options and what's really going on and the risks,
and so when the doctor says this is going to
swell your brain or this is going to do that,
or this is going to damage the other tissue, it
makes sense to you and helps you make those decisions.
Speaker 3 (08:23):
So radiation is different than the particle beams.
Speaker 1 (08:27):
It's the same.
Speaker 3 (08:27):
Yes, it is the same.
Speaker 1 (08:28):
By radiation, I just mean shooting particles and we'll get
into that in a minute. But yeah, radiation particle beams.
To me, it's the same deal.
Speaker 3 (08:35):
Excellent, all right, So let's start with, you know, probably
the most interesting part the biology.
Speaker 1 (08:41):
That's why this is another fun topic because I was like, ooh,
physics curing biological issues.
Speaker 3 (08:47):
Yeah yeah, although I think at the top of my
list of fun is not cancer, but what cures for
cancer is pretty awesome. So go ahead, let's hear the
physicist explanation for what is cancer?
Speaker 1 (09:00):
Wait, I'm explaining it. I was hoping that. Well, I'm
going to give it a start and you chime in
with your informed details.
Speaker 3 (09:08):
Okay.
Speaker 1 (09:08):
My understanding is it's a whole collection of things, like
they have something in common, but you can't really say
cancer is like one thing in general. It's cells growing
out of control, but the causes for that can be manyfold, right.
Speaker 3 (09:21):
Yeah, I have a friend who studies cancer, and he
was telling me that even just one kind of cancer
can be caused by so many different mutations that that
makes it pretty difficult to treat because often you want
to know exactly what kind of mutation it is that
causes it. And so now we genotype people's cancers to
try to figure out exactly which of the many mutations
is causing it to target our treatment. So, yes, it's
(09:43):
a lot of stuff that can cause cancer, but don't
let that keep you from sleeping at night.
Speaker 1 (09:50):
But in general, it's when something goes wrong with the
cell's growth function. Right, So cells are constantly replicating, called
this mitosis, and the nucleus like splits the DNA and
copy itself, and there's a whole bunch of genes that
control that copying, but errors can creep in, of course,
and then cells keep doing this duplicating themselves, copying themselves
for a while, and then they stop. And this apoptosis
(10:12):
is when it sells like I'm done, disassembles itself and
gets like reabsorbed into the body. And this huge variation.
Like some cells only live for like very short periods,
like a day. Bone cells can live for like thirty years.
Neurons can live forever. So you have this whole mechanism
where cells are splitting and making copies of themselves and
eventually retiring. In order to get cancer, a bunch of
(10:34):
things have to go wrong in just the right way.
So it's kind of amazing that cancer happens as often
as it does because it requires like multiple mutations, multiple
wye for this whole process to go wrong.
Speaker 3 (10:45):
Yeah, I'm gonna go ahead and give you a pod
in biology, congratulations.
Speaker 1 (10:52):
So the first thing that has to go wrong is
that the gene that controls how often you're going to replicate, right,
these oncogene the genes that control replication have to go crazy.
So maybe there's like a mutation, or maybe you just
got a bad gene from your parent or something, and
this gene that controls how often your splinting can go crazy,
so you just get like uncontrolled replication instead of like
(11:15):
doing it at a reasonable rate.
Speaker 3 (11:16):
Yeah, it could be because you got a gene from
your parents. It could be because you were exposed to
something that caused a bad change in your genetic code,
you know. For example, that's what happens with skin cancer
is you acquire a lot of mutations from the sun,
which I know well and where your sunscreen. Kids.
Speaker 1 (11:32):
Fascinatingly, that's an example of radiation causing cancer right there.
What's happening are like ultraviolet photons are penetrating into your
body and causing damage to your DNA, which triggers cancer.
So for a lot of people they connect radiation with
the cause of cancer instead of the cure of cancer.
And actually radiation can end up on both sides of
(11:53):
that equation.
Speaker 3 (11:54):
Yeah. Yeah, but I think instead of fascinatingly, I would
have said something like suckily or tragically. Yeah. I have
a big scar on my forehead, which my daughter will
sometimes be like, oh it's hard to look at, mom,
and I'm like, kiss my butt, kid, But you don't
have to live with it anyway.
Speaker 1 (12:11):
Is that a scar from a cancer removal?
Speaker 2 (12:13):
Yeah?
Speaker 1 (12:14):
Yeah, glad they caught it.
Speaker 3 (12:15):
Yeah, me too.
Speaker 1 (12:16):
So we were talking about how cancer cells grow uncontrollably,
but that's not enough to be a cancer cell, right
Just because you change the gene it controls replication doesn't
make you already cancer. It's because the cell can just die, right,
So in order to have cancer, you need to have
uncontrolled replication, and you need to break this apoptosis. This
thing that tells the cell to turn itself off because
(12:37):
you're done, buddy, needs to also break and so you
have to have uncontrolled replication and the cell has to
be immortal. This is what I meant earlier when I said, like,
you require multiple mistakes in the cell, from like happy
cell that's growing nicely and playing kindly with everybody, to
cancer cell that's going to grow uncontrollably, making more of
itself and refusing to die off.
Speaker 3 (12:59):
Yeah, feeding itself, managing to get more blood vessels to
be made to feed those cells and stuff, and then
it starts choking off other things. And yeah, thinking about
all the different ways our bodies can break down, it's
amazing they ever do anything right. But Kelly's catastrophizing today.
Speaker 1 (13:16):
That is a terrifying rabbit hole to dig into. And
I've done that sometimes, especially you know, when under the
influence of various substances, and I'm like, wow, I am
this pulsing, throbbing meat machine, And it's incredible that it
just keeps working and for most people, just works for
decades without lots of issues. It's amazing that it survives
(13:37):
this long. On the other hand, of course, if it didn't,
we wouldn't be here, and so obviously evolution has done
its job.
Speaker 3 (13:43):
That's right, Well, we all made the wake up list today,
so hurrah for all of us.
Speaker 1 (13:47):
Correct, what's the wake up list the people who didn't
die in their sleep? That's dark? Well, oh my gosh.
Speaker 3 (13:56):
Yeah, that is what it means. So anyway, Well.
Speaker 1 (13:59):
Do you wake up every morning and you're like, ah,
I was on today's wake up list?
Speaker 3 (14:03):
No, but I do wake up in the mornings and think,
you know, you don't know how many days you've got,
so you should try to make sure you're doing doing
good by you and your family and your kids.
Speaker 1 (14:11):
But yeah, anyway, all right, So cancer is uncontrolled, constant growth.
It builds these blood vessels, It SAPs the resources, and
you might think, why do I care if I have
a little blob of cells that are growing out of control. Well,
you know, they're growing out of control, so they get
bigger and bigger, right, And if it's like that's in
your brain, it's going to press on important stuff like
(14:31):
the things that control your balance or your memory or
your speech patterns, and that's going to be an issue.
Or if it's in your pancreas or if it's in
your liver, right, it can impede the function of the
normal cells. And also it can spread, right, that's the
real danger. If you have cancer and it's just in
one spot and you're like, Okay, I got to get
this blob out, then they can just do surgery and
(14:52):
cut it out, or they can do radiation like we're
going to talk about. But the time that cancer really
becomes deadly is when it spreads to the rest of
your body. And this is what means pastasis. Is usually
it spreads into the bloodstream and then the blood carries
it all around the body and it lodges somewhere and
then it keeps doing its cancer thing. And now instead
of having one blob that's growing out of control that
(15:12):
you can maybe deal with, you have lots of them,
uncountable number, and they're also spreading, and so very quickly
it goes out of control. So often it's crucial to
catch cancer early before it metastasizes.
Speaker 3 (15:24):
Future casting here, I'm not going to be sleeping well
tonight we're.
Speaker 1 (15:29):
Just doing a lot of ironic foreshadowing because we're going
to get to the bit where we're carrying it. We
just need to set it up, all right, So all right, great,
But this is not a small issue, right. Cancer is
a real killer. Yeah, three percent of people in the
United States are cancer survivors. It's a huge number. Cancer
hits about one hundred million people a year, and there's
like ten million deaths a year. So like, this is
(15:53):
a real issue. You know, a huge fraction of our
healthcare budget is focused on cancer, as it should be.
This is what motivated like Joe Biden's cancer moonshot, Like, hey,
can we crack this thing? But as you were saying earlier,
one of the big struggles with dealing with cancer is
that it's not just cancer. It's cancers. Is like more
than one hundred different types of cancer, and they come
(16:15):
in all kinds of varieties. Like a huge fraction of
them are just caused by tobacco use, Like twenty percent
of all cancer is like from smoking or some kind
of like snorting, their sniffing, their sucking on those leaves.
But there's another chunk like twenty percent that are due
to infection like some virus comes in and injects its
DNA into your cells, and now those cells are cancerous
(16:37):
because they've changed your cells in exactly the right way
to trigger that cancer.
Speaker 3 (16:41):
Jerks, jerks.
Speaker 1 (16:42):
But the good news is, like we know how to
deal with viruses, so now we have like vaccines against cancer.
Speaker 3 (16:47):
That's amazing, right, yes, incredibly cool.
Speaker 1 (16:51):
Like cervical cancer caused by the human papilloma virus, Like
we have really treated that and really the rates of
that cancer have dropped tremendously, so they're real here. Even
though it's lots of different kinds of cancers which require
lots of different kinds of approaches, people are working hard
on this and really making progress. So you know, go
big pharma, go mds, Like, thank you to all those
(17:12):
folks working on the front line and saving those lives.
Speaker 3 (17:15):
Amen. And also, you know, to focus a little bit
more on silver lining. You know, the reason so many
of us are getting cancer and having cardiovascular problems these
days is because a lot of us are living to
be old enough for this kind of stuff to become
a problem. You know, before there's a pretty good chance
you wouldn't survive to be five, But now a lot
of us, you know, live a lot longer.
Speaker 1 (17:34):
And cancer doesn't just strike humans. You know. One of
the main reasons that rats die, for example, is that
they live long enough if they're well fed, yeah, to
get cancer. We had pet rats and after a couple
of years, they each got these big tumors that were
like dragging these things around, like these big blobs hanging
off their bellies. And Katrina has a good friend who
(17:54):
does cancer studies on rats, and she knows how to
operate to remove tumors, and so she offered to operate
on our rats. And I was like, yeah, I don't
know if we need to bring our rats into your
like special expensive facilities. Like at some point, you know,
you're just fighting a losing battle. You cut these tumors out,
you know there are more coming. But it was sad.
(18:15):
You know. Rats are wonderful little critters. Yeah, and they
don't live very long, and we bonded with them. But
on the flip side, that's when we decided we needed
a longer living critter. And now we have a dog.
Speaker 3 (18:25):
Oh that's fantastic.
Speaker 1 (18:26):
Yeah, but you're right, the bigger picture is as we
live longer, as we tackle these things, we just discover
new things that were going to kill us. Right, the
front just moves and we have a new battle to fight.
Speaker 3 (18:37):
That's right, and it's time to take a break. And
when we get back, we're going to talk about why
sharks don't get cancer, and we're back. That was a
(19:05):
trick setup, because even though you hear over and over
again the sharks don't get cancer, sharks do get cancer.
Speaker 1 (19:11):
Gotcha, what, Kelly, are you dispelling another pop sign? Myth? Yeah?
Speaker 3 (19:16):
Sorry?
Speaker 1 (19:16):
So why was it so commonly said that sharks don't
get cancer? Was that just purely invented or is it,
like a crab study, a misunderstanding of real science.
Speaker 2 (19:25):
I don't know.
Speaker 3 (19:25):
It could be both. I mean, I imagine that a
lot of times when animals in the wild get cancer,
it debilitates them to the point where something else gets them,
you know, a predator eats them, for example. And so
it just could be that we didn't encounter many sharks
that had tumors, or people who did noted it but
didn't you know, publish on it or something. And so
I don't know, somehow this misconception entered its way into
(19:48):
the twitter sphere or the exosphere whatever. We call it now,
but anyway, yes, sharks get cancer.
Speaker 1 (19:55):
The exosphere is actually a science word already. It's like
when you don't have an atmosphere, you have particles that
are just flying around, not interacting with each other. Like
the moon has no atmosphere, but it does have an exosphere,
even though there's nobody on the moon posting on X.
Speaker 3 (20:10):
But that's spelled exo, right, yeah, so this would be
like the xh O sphere or something.
Speaker 1 (20:17):
You can't have two words that sound exactly the same.
Oh my god.
Speaker 3 (20:20):
I mean, you know, the English language is the worst
in terms of us spelling of stuff.
Speaker 1 (20:24):
So the particle beams can't cure the problem of the
English language, but maybe they can help with cancer. So
let's lower our sights and think about that instead.
Speaker 3 (20:32):
So let's overview some of the ways that we can
deal with cancer.
Speaker 1 (20:35):
So, if you have cancer, your options are often surgery.
Like if it's localized, it hasn't spread, and it's not
next to something else really really delicate, then off you
can cut it out, Like if you have skin cancer,
they can just clip that thing off because you don't
need to go inside the body, it's not next to
anything else dangerous. And it's probably hopefully hasn't spread yet,
and so they can just cut it off. Whereas if
(20:58):
you have, for example, something growing inside your brain, surgery
is more complicated because they've got to go into your
brain and maybe it's touching something else really delicate, and
it's hard for the surgeon to cut out the whole
thing without touching that delicate nerve and maybe impacting your
brain function. Right, that was the great fear for my
two friends who recently had brain surgery because of growth.
Speaker 3 (21:19):
You had two friends who had brain surgery. Are they
both doing okay?
Speaker 1 (21:22):
Both of them are fine, Both of them are scientists,
and both of them were back to work amazingly just
like a month after brain surgery. So it's incredible what
modern medicine can do. Ten hour surgery got to cut
out these lumps, and yeah, they're back to work and
making the same terrible dad jokes ever email that they
were before surgery. So I can't even blame it on
the cancer.
Speaker 3 (21:43):
My daughter is really into puppeteering, and her hero Adam
Krutinger passed away from a brain tumor recently, and so
these are difficult things to tackle.
Speaker 1 (21:52):
Yeah, it's scary, but you know, there's a lot of
people working hard and dedicating their lives to making this better.
So surgery is a great option if it's still localize
and it's not close to anything else that you're risking.
Another option, of course, is chemotherapy, and we kind of
a whole episode on that if you like. But essentially
you're just drinking poison, yeah, and you're hoping the poison
kills the cancer, or the poison is designed by clever
(22:14):
chemists to kill the cancer faster than it kills you,
and so it's a race of attrition there.
Speaker 3 (22:20):
Yeah. As I understand it, cancer cells tend to replicate
faster than other things, and so it's targeting very quickly
replicating cells. And that's partly why you lose your hair,
because you've got like very fast replication happening in those
follicles and they kind of get shut down for a
little while, so your hair falls out. And actually, we
should get someone who knows what they're talking about, because
(22:41):
I'm just vaguely remembering these facts and they could be wrong,
but you're.
Speaker 1 (22:46):
Right in each case. What we're trying to do is
highlight a particularly sensitivity to cancer and then take advantage
of that in our attack, and the same thing is
going to be true for radiotherapy, which is particle therapy,
and we're shooting beams at the cancer. The idea is
that these cancer cells have a mutation in the place
(23:06):
where they're doing their DNA replication right when they're replicating,
instead of doing a normal rate, they're doing an uncontrolled rate.
And so these cells are actually pretty bad at repairing damage. Right,
They're already damaged, and they're worse than normal cells at
repairing damage. And so if you attack them and try
to break up their DNA, they are more sensitive to
(23:27):
those kind of attacks than normal cells.
Speaker 3 (23:30):
Ah okay, but so you told us that they're also
resistant to apoptosis, so resistant to breaking apart. Is the
idea just that if you mess up the DNA enough,
they just kind of like die and wither away.
Speaker 1 (23:42):
Yeah, okay, hmm exactly. I asked Katrina about this actually,
and she said, another way to look at a crazy
cancer cell is that it's less resilient. It has all
these broken repair mechanisms that makes it easier to take down.
And so if you can shatter its DNA or attack
its DNA, it's less likely to be able to to survive,
so they're more fragile in that sense, they're more susceptible
(24:04):
to radiation than the normal cell.
Speaker 3 (24:06):
Okay, but chemotherapy often acts throughout your body, and it
would be really nice to be able to target so
you don't get negative impacts spread throughout the body. And
so particle therapy, I'm guessing, can give us that.
Speaker 1 (24:17):
Yes, exactly. Particle therapy is not just like broadly shooting
radiation at your whole body. We're shooting particles in a
very narrow beam, so we can aim where it goes.
If you have a tumor in your brain, we're not
shooting particle beams into your toes, and we can get
very very precise with it. And you can think about
it in three dimensions as well, because imagine you have
(24:38):
a tumor in your brain somewhere right the goal is
to have the particles hit the tumor and nothing else
that would be ideal. Right now, we can't do that perfectly.
We have to shoot it through some normal tissue to
get it to the tumor. So we have a few
ways to avoid damaging the normal cells along the way,
and we're going to talk about one of them being
(24:58):
particle choice, but the other one very simple, which is
that you just shoot from a few different angles and
those beams intersect at the tumor, so the beams aren't
going to hit some normal cells, but the normal cells
all just get like one beam, but the tumor gets
like four beams. Or the generalization of this is that
you have a single beam that sweeps around you, and
as it rotates, it's consistently on the tumor, but the
(25:21):
normal cells are only getting it part of the time.
So the tumor gets it constantly and it spreads out
the beam across a bunch of other normal cells, so
they thee is to deposit more energy to do more
damage on the tumor cells than on the normal cells.
And so the way you do that is by shooting
from multiple angles or by scanning around, so the beam
stays constantly on the tumor but is spread around on
(25:43):
the normal cells. Does that make sense?
Speaker 3 (25:45):
That does? Yeah. So I've talked to a few friends
who have had cancer and the treatment that they got
saved their lives but increased their future risk of getting
cancer because it damaged the DNA of some of their
other cells. Do we know for this treatment when you
get I don't think I would love the idea of
having particles go through all of my brain, even if
I knew they were still focused on one spot. But
(26:06):
you know, it still sounds better than the alternative of
letting the tumor grow. But do we know with this
method forty years down the road, does it increase your
probability of getting a tumor somewhere else?
Speaker 1 (26:16):
It definitely increases your probability of getting a tumor in
that otherwise normal tissue, because you're shooting beams through it,
and you're depositing energy and you're damaging DNA, and so yeah,
you're setting yourself up for cancer in those cells. But
people are trying to make this more and more accurate
by controlling the dose, by doing really thin scans, by
making sure that the dose is like the minimal necessary.
(26:38):
People used to have really high doses to make sure
they got the tumor, and now they can scale that
down and have better models for calculating the dose. They
just used to assume, like the human body is water.
Now they're like, okay, well there's other tissues in there,
and we need to take that into account. Think about
the scattering, you know, and now they think more about
the angles, what is it going to go through. As
time goes on, we get better and better at this,
(27:00):
and also crucially, we're choosing the particles we shoot because
that can determine where the energy lands.
Speaker 3 (27:06):
Okay, so let's talk about what our options are for particles.
Speaker 1 (27:09):
Yeah, so number one is photons. Right, We all get
radiation when we go to the doctor for a broken bone.
They use X rays to take a picture of your insides.
And X rays pass through the body, but they're absorbed
differently by bones and by soft tissue, and that's why
you can see through the body. Right, And this is
a whole fascinating topic here about transparency, like why can
(27:32):
visible light not go through the body but X rays can.
The answer is that for photons, how far they go
through and where they deposit their energy or if they
do deposit their energy, depends on the wavelength of light. Today,
we're just going to talk about that interchangeably. Right, Radiation
is made of particles. One example is a photon. We'll
also talk about electrons and protons, but we'll start with
(27:53):
photons mostly X rays.
Speaker 3 (27:54):
I feel like I'm still not really understanding how X
rays work. Can you give me some more detail.
Speaker 1 (27:59):
Let's think about what happens when a photon hits your body, right,
And let's say, for example, it's a normal visual light photon,
like a red photon that's just flying around. Well, what
happens when it hits your body is it finds a
bunch of atoms, and those atoms all have energy levels. Right,
there are electrons whizzing around those atoms, and they can
absorb some photons. If an electron has an energy level
(28:22):
that matches the energy of the photon that's coming in,
it can eat it. Like if the electron is an
energy level five and it needs a certain amount of
energy to go up to six or to seven, and
a photon comes along with just that much energy, boom,
it can gobble it up. So this is atomic absorption
and also atomic emission. Like we talked about recently in
our episodes about what color is the sun, that same atom,
(28:43):
if the electron is in the higher energy level, it
can release that energy shooting off that photon. So atoms
can absorb photons of specific energy levels. Right. This is
why red paint is red, right, because it absorbs everything.
But the red reflects the red. The red doesn't get
absorbed by those materials. This is why glass is transparent
because there are no atoms in the glass that can
(29:06):
drink light in the visible spectrum, right, so it just
passes through. So for very low energy light, like the
kind that's in the visible spectrum, whether or not it
goes through or whether or not it's absorbed in, deposits
its energy. And that's the crucial thing, right for curing
cancer or treating cancer, you want to deposit your energy
depends precisely on what energy you have. But for treating cancer,
(29:26):
we're not normally shooting just like light bulbs at people, right,
We're shooting higher energy stuff. And so at higher energy
what happens is the photoelectric effect. Instead of the electron
just going up an energy level, you kick the electron
off of the atom, right, You completely ionize it. So
if you have high enough energy like X rays for example,
they can kick electrons out of the atom. This is
(29:48):
the photoelectric effect that Einstein used to like discover quantum
mechanics and all that kind of stuff. And then at
even higher energy levels, what happens to a photon is
that it pair produces it turns to an electron and
a positron because of the nuclear electric field, and so
what happens to a photon depends a lot on its
energy relative to the matter. And so X rays are
(30:11):
a typical thing that we use in radiotherapy, and they
do penetrate, right, and so they have high energy, so
they can get pretty deep into your body. Like if
you just shoot red light at somebody, it's absorbed at
the skin, but X rays can penetrate, they can go
further in. The downside of X rays for treatment is
that they leave a lot of energy in the first
few layers, like they deposit energy and then they sort
(30:32):
of peter out, and so a lot of the energy
is deposited near the top. So if you want to
get like deeper in you have like a tumor like
three centimeters under the skin, you have to shoot a
lot of X rays at it, and the normal cells,
the cells you don't want to treat that are between
the skin and the tumor are also getting a lot
of X ray energy. So that's why for X rays
it's crucial to like rotate it around the body.
Speaker 3 (30:53):
And so when you go to get an X ray
and you wear a lead. Oh, that lead is not
covering the spot where you're getting the X rays, ring
everything else, got it?
Speaker 1 (31:01):
Okay, yeah, exactly, it's covering your critical bits. Yeah. Because
X ray penetration also depends on the atomic nucleus, right.
If the atom has high Z a lot of protons
and neutrons in the nucleus, then it's likely to absorb
the X rays rather than let them through, and so
the lead is like a shield for you.
Speaker 2 (31:18):
Got it.
Speaker 3 (31:18):
I really messed up my ankle when I was pregnant,
and I was so worried to get an X ray. Uh,
you know, I didn't want to hurt little Ada. But anyway,
she was fine thanks to the lead blanket. Or maybe
she's weird because something went wrong, but she's weird in
the best way possible.
Speaker 1 (31:35):
So anyway, Well, they used to take X rays with
incredibly bright sources, right, and now they've reduced those X
rays far as they can and they can still see
inside your body, but with much much lower luminosity. They've
improved the detectors they put on the other side, so
X rays are much safer than they used to be.
If you're going to get an X ray in like
the fifties or sixties. Can you're really dangerous, but now
(31:57):
it's much much safer. Yeah, the get do not deliver
a dangerous amount of radiation. And there are other things
we do in our lives, like fly on an airplane,
that do increase our radiation dose. But people don't really
think about it that way very much.
Speaker 3 (32:10):
No, I don't, but I'm about to go on a
long plane ride. Thanks for ruining it for me.
Speaker 1 (32:14):
One more thing to worry about.
Speaker 3 (32:16):
That's right. Oh man, I just sleeps so good tonight. Okay,
So how do we make these X ray beams? Daniel?
Speaker 1 (32:22):
Yeah, exactly. If you want to make a beam of
red light, you just like heat of a tungsten filament
and it glows in the white and you can have
like a prism and filter out the red light. But
if you want X ray beams, we don't have stuff
that glows in the X ray. You need like super
duper crazy hot gas. Like sources of X rays astrophysically
come from like gas near black holes and stuff, and
(32:43):
so we don't have that here. It's not easy to generate.
So instead, what you just do is you just heat
up the electrons, right, take a bunch of electrons, speed
them up using an electric field. Electrons respond to electric fields,
so they're going really really fast. This is a lot
like what we do in particle physics, and then bend
them with a magnet. Do you have an electron super
high velocity going in some direction it encounter as a
(33:05):
magnetic field was to do it? Bends? Right, And when
an electron bends, the only way you can do it
is by emitting a photon. Right. That's how electrons bend,
and in a sense, it's interacting with the electromagnetic field,
and so photons are a natural way for that to
do it. And so when it's going at high speed
and bends through a magnet, it tends to emit a
high energy photon and that's our source of X rays,
(33:28):
which is why you often have like X ray crystallography
facilities at places with particle beams, like an Argone National Lab,
they have like a world class X ray crystallography set
up because they're also good at particles cool.
Speaker 3 (33:40):
Okay, so this sounds like a really great method for
creating X rays and finding where tumors are, But this
is not something you'd ever use to treat a tumor.
Speaker 1 (33:47):
Right, Well, you can use these to treat tumor. They're
not great because they, as we said before, they pass
through the body and they deliver energy in many layers.
But you can use X rays, you can use high
energy photons to treat a tumor. So these days we
have more advanced techniques than are superior.
Speaker 3 (34:03):
Yeah, okay, so we were just talking about electrons. Can
you skip the phase where you use a magnet to
get X rays and just use those electrons directly?
Speaker 1 (34:11):
You can use electrons and shoot them at people, right,
and they will deliver their energy. But electrons are not
very penetrating. Right, Your skin mostly stops electrons. At very
low energy, the electron will just like ionize atoms and
be absorbed. At very high energy, the electrons will emit
a bunch of radiation and slow down. It's called bremstrong lung,
(34:31):
which is German for like breaking radiation. And so electrons
are not very penetrating, mostly because they're very very low mass,
and so like any interaction basically stops them because even
at high energy, they don't have a lot of momentum
because their mass is so low, and so they're not
a great choice for penetrating the gold standard. The thing
you really want is some kind of radiation which takes
(34:52):
a while to stop, which like flies through your body
and then deposits its energy all in one go somewhere
deep in your body in a way that you can tune.
Speaker 3 (35:02):
And so we've talked about photons and electrons, and let's
let the listeners guess what kind of particle it is
that does that, and we'll get back to it after
the break. All right, So we've already talked about photons,
(35:33):
we've already talked about electrons, but the best method is
one we haven't talked about yet. And by process of elimination,
I'm gonna guess.
Speaker 1 (35:40):
It's protons because you only have three particles in your mind,
that one.
Speaker 3 (35:45):
Well, you know, you told new particles are complicated, But yes,
I guess those are the first three that come to mind.
Speaker 1 (35:52):
Well, that's fair because the universe is mostly made of protons, electrons,
and photons. So that's a good set to have in
your mind. Good choice, Kelly.
Speaker 3 (36:00):
I also have this outline in front of me that
says protons.
Speaker 1 (36:04):
Next, So that makes you sound smart.
Speaker 3 (36:06):
That's right. That's my trick.
Speaker 1 (36:09):
Protons are a great choice for treating cancer, and protons
are also one of the favorite toys of particle physicists
because we can accelerate them to really high energies and
bend them around. They have a lot of mass compared
to an electron, so you can get them going really fast,
and when they go around curves, they don't emit as
much radiation because they're heavier, and protons, because of the
(36:29):
way they interact with matter, can penetrate deeply and deposit
their energy deep under the skin without harming as much
the tissue in between.
Speaker 3 (36:38):
Oh that's fantastic. Yeah, why does it work that way?
Speaker 1 (36:41):
Yeah, it's fascinating. Protons can interact with the electrons and
matter right or with the nucleus, and which one they
do depends on their velocity. So when they're going really fast,
they basically can't see the nucleus and they just interact
with the electrons. But it's like glancing collisions. It's too
big and heavy to really get slowed down by these electrons.
(37:02):
It's like a bulldozer are going through a field of snowmen. Right,
It's just like plows right through them hardly, gets hardly
gets slowed down. Just reading Calvin and Hobbes and so
perfect and so like each snowman that the bulldozer hit
slows down a tiny little bit, but it really doesn't
deposit a lot of energy. It doesn't get slowed down.
But this interaction is dependent on the velocity squared, and
(37:24):
so at some point it reaches some threshold where it
does get slowed down enough. Now it's going to interact
with the atomic nucleus and that is going to rapidly
sap it of energy. And so there's like a threshold
there above which it can mostly ignore what's going on
inside the nucleus and just plow on forward. But when
it gets too slow, then all of a sudden, it's
a very strong interaction with a nucleus and it deposits
(37:46):
a lot of its energy right there. And so that's
why it's excellent of course for treatment. And this is
called the brag peak.
Speaker 3 (37:52):
I remember reading about the brag peak because when I
was reading about space radiation. One of the problems with
trying to understand and how radiation impacts people is that
you often study it in rodents yea. And rodents are
just smaller than humans. There's less mass that the proton
needs to go through and if the particles in some
(38:13):
cases are just like shooting through the rats, then you
don't really understand the impact of the radiation because the
particle didn't stop and release all of its energy inside
of the body of the organism. And so there's some
concern that, like studying rodents, doesn't tell you exactly what
you need to know because humans are just bigger, and
we're more likely to stop a particle because it's running
into more stuff. Does that make sense?
Speaker 1 (38:34):
Yeah, that makes perfect sense. Can't you solve that problem
just by like, you know, gluing a bunch of rats
together into like a huge sphere of rat and then
you could have enough rat to stop the protons.
Speaker 3 (38:43):
Daniel, you missed your calling in biology.
Speaker 1 (38:46):
I'm sure we could get that past the IRB, right,
I don't see any problems with that.
Speaker 3 (38:50):
That sounds totally ethical. I'm sure that have high quality
of life.
Speaker 1 (38:54):
I wonder if you need to have the mouths, I'll
point it out, but then you know what's going on
in the inside. Yeah, anyway, this problem not a great idea.
Speaker 3 (39:00):
This gets.
Speaker 1 (39:03):
So the brag peak is a great way to understand
where the energy is deposited. By these various particles. So
if you imagine like we're talking about as a function
of the depth, how deep into the tissue. Start out
with electrons mostly deposit energy the very surface. Photons deposit
a lot of their energy the surface, then it fades gradually,
but protons like deposit almost no energy, and then all
(39:25):
of a sudden boom, you're like ten centimeters in. They
deposit almost all of their energy there. That's the peak
that they're referring to when they say the brag peak.
And this is excellent, right, because if you could tune this,
if you could say, oh, I wanted ten centimeters in
or fifteen centimeters in, then you could basically just shoot
a beam and have a deposit most of its energy
deep within the tissue and spare the normal tissue where
(39:45):
the protons are passing through. They're still plowing through those
electronic snowmen, but they're not really doing a lot of damage.
Speaker 3 (39:52):
That's amazing, right, So tell me, in a practical sense,
how would you do this?
Speaker 1 (39:55):
Yeah, so why changing the energy of the protons. You
can change the depth, so where it deposit its energy
depends on the velocity. Right, So if you start out
with a lot of velocity. Then you're going to go
much deeper and then all of a sudden deposit your energy.
If you're very close to that threshold already, then you're
not going to go very far and then cross over
that threshold where you're depositing your energy. So you can
(40:16):
tune the depth where the protons are depositing their energy,
which means doing damage to those cells, breaking up the
cancer DNA by tuning the energy of the protons. So
you already have like two dimensional pointing just by pointing
the beam at something. Right, now you have the third
dimension of control. By tuning the energy of the beam,
you can go deeper, you can go less deep, and
(40:38):
so you can do this three D they call it
tensile beam scanning, where you're changing the direction of it
and you're changing its energy simultaneously, so you can trace
out the three dimensional shape of the tumor. Right, you're
probably imagining a tumor as a sphere, and that's what
a physicists would do, and that's probably what they did
twenty years ago, Like let's assume a spheertical tumor. But
(40:59):
what that was clueless physicist accent I don't know.
Speaker 2 (41:04):
Was it German?
Speaker 3 (41:05):
That sounded vaguely?
Speaker 1 (41:07):
It was a rough average of all the accents I've
heard it.
Speaker 3 (41:10):
Cern there you go, okay, perfect all there's.
Speaker 1 (41:12):
A little Russian in there, a little German, maybe, some Italian,
and a smattering of Japanese. No, all right, I'm equally
offending the whole world right now. But imagine if you
can do a three D scan with like an MRI
and you can see exactly where the tumor is, and
tumors are never simply shaped, they're like long, and then
they got a blob over here. And what you ideally
want to do is deposit energy everywhere in the tumor
(41:33):
and nowhere else. Well, with a proton beam, you can
do that because you can aim the beam and then
you can change the energy. You go back and forth
and back and forth over the tumor. And then when
you change the angle and now you're intersecting a different
part of the tumor with a different shape and different depth,
Now you change the energy the protons back and forth,
back and forth. You can scan in three D. You
can like trace out the whole tumor, use the brag
(41:55):
peak to deposit energy there and almost nowhere else.
Speaker 3 (41:59):
That's amazing. So do we We have like complicated models
that sort of figured that out ahead of time, and
you just press a button and then it automatically gets
the whole tumor, or is somebody like going, you know,
step by step and like moving the beam around to
get every little part of the tumor.
Speaker 1 (42:13):
It's all computerized, absolutely and controlled, so nobody's like, oops,
I slipped and I you know, fried your eyeball or whatever.
The disadvantage is that proton beams are harder, right, Like
electron beams are easy to make electrons or light that
you can accelerate them easily, X ray beams there's lots
of ways to make that. Proton beams are complicated, and
the magnets that bend them and point them are huge.
(42:36):
We're talking like hundreds of tons of magnets usually wow.
And so these facilities are much more specialized. Say sound fantastic,
and if you get cancer, I hope you have access
to one, But there are not that many of these
facilities yet in the world because they are big and complicated.
Speaker 3 (42:53):
Is this also a kind of new treatment for cancer?
How long has this been around?
Speaker 1 (42:57):
It's an idea that's been around since the forties. Like
Robert Wilson, the guy who designed Fermilab and did all
sorts of crazy architecture and it was a huge important
particle physicist predicted this in the nineteen forties in a
paper and it was first used in the fifties. It
was pretty expensive until around twenty five years ago when
people made some improvements in magnet technologies. Now, instead of
(43:20):
there being like one center at Fermilab, for example, there
are a few dozen centers worldwide, and as of like
ten years ago, like one hundred thousand people had received
this treatment. So it's still not the overwhelming treatment for cancer,
mostly because there aren't that many centers and they're expensive,
but it's definitely the best treatment you can get.
Speaker 3 (43:41):
So we're not medical doctors, so I just I want
to clarify a little bit for the best treatment we
can get. That probably depends on what kind of tumor
you have. Yes, yeah, okay, So.
Speaker 1 (43:52):
From a particle physicist point of view, thinking about maximizing
the control of the energy dose, proton beams are from
physics point of view, the best way to optimize the
energy dose delivered. But please speak to your doctor about
your treatment needs. Don't listen to me.
Speaker 3 (44:08):
That's right, You're welcome, my heart. We had all the
right caveats there.
Speaker 1 (44:14):
But for a particle physics nerd, it's very similar to
what we do with the Large Adron Collider. Like how
you make a proton beam, Well, that's what we have
with the Large Adriene Collider is a proton beam, and
so the steps are very similar. Like you start with hydrogen, right,
protons are everywhere. Then the most common thing in the universe,
the universe mostly hydrogen, which is a proton and an electron.
Take some hydrogen, heat it up, so the electron goes
(44:36):
away and you have protons, right, and then you just
need to accelerate them, which means put them in an
electric field. We used to just use flat electric fields
to accelerate particles. Now we use these cool things called
RF cavities. These things have oscillating electromagnetic waves, so the
particles like surf on them, which is really cool, and
get accelerated more easily over shorter distances to higher energies.
(44:58):
And then you have magnets to keep them going in
a loop. And that's exactly how the Large Hadron Collider
works and so these are lower energy than the large
hadron collider. You don't need crazy energies in order to
deposit a dose in your brain. But it's the same technology.
And so because it's more similar to the LAC than
to like your standard technology, it is more specialized and
(45:19):
it is more rare.
Speaker 3 (45:20):
All right, So let me tie this back to parasites.
All right, So when you have a parasite in your
body and then it dies, that can often be worse
than having a live parasite in your body, because now
there's all this dead tissue in your immune system like
responds to it. Does this process have to get done
in stages? Because if you've killed too many of your
cells all at once, your brain now has all of
this dead stuff that it needs to sort of process
(45:41):
and deal with. Or do you not know because I
were way outside of physics.
Speaker 1 (45:45):
Now I don't know in great detail, and maybe some
cancer doctors can write in and let us all know.
But I do know that the immune system will respond
to this. And for example, if you get radiation treatment
on a tumor, it can make the tumor swell even
if it dies, Like the immune response there can make
the tumor swell, which can also be dangerous because if
(46:06):
it's next to something delicate, you don't want it to swell.
And so again talk to your doctor about what the
best treatment is for you and all those side effects.
But we actually do have some data about what would
happen if you shot a super duper high energy particle
beam into your head, because it happened once. What Yeah,
there was a Russian guy for Ghoski and he basically
(46:27):
was looking down the particle beam. He was doing some
repairs on the beam and they turned it on. Oops,
and so it went right through his head. And amazingly
the guy survived.
Speaker 2 (46:38):
Wow.
Speaker 1 (46:38):
He ended up with epilepsy and some hearing loss, and
some people say his personality changed a little bit, but
he lived his life otherwise. So I wouldn't recommend it,
but it is possible to survive LEDC level energy proton
beam through the brain.
Speaker 3 (46:54):
Oh my gosh, this happened at the LAC. No.
Speaker 1 (46:56):
This was definitely not at CERN or the large Hage
of Competor. This is in nineteen seventy eight at the
Institute for Hinenergy Physics and Provino back behind the Iron Curtain,
and it was a nattally Burgoski.
Speaker 3 (47:08):
Poor guy. Well, I'm glad he made it.
Speaker 1 (47:10):
We're all glad that he survived, and we're starting that happened.
I hope that it doesn't happen to you. But you know,
the bigger picture is that particles interacting with matter is complicated.
Particles from the sun and from the atmosphere can mutate
your DNA and cause cancer, but particle beams can also
deposit energy in those cancer cells in a very defined
(47:31):
and very calibrated way to help treat your cancer. And
so particles are on both sides of the coin of life.
Speaker 3 (47:38):
That's right. And I'm guessing that most of the folks
who are working on these particle related questions did not
have in mind that this would end up being a
treatment for cancer. So you know, we're gonna go ahead
and bang that drum that we've been banging so much lately.
Fund basic research. This stuff results in amazing life saving technologies.
Speaker 1 (47:56):
Yeah, and you don't know if that's studying to like
how ducks mate, or how to synthesize this random chemical
or whether this parasitoid wasp, But does this or that
is going to yield the next great bit of technology.
That's going to save your life or a loved one,
or transform our lives into some way we can never imagine.
Speaker 2 (48:16):
Amen.
Speaker 3 (48:17):
All right, everybody, thanks for listening, and we'll see you
on the next show. Daniel and Kelly's Extraordinary Universe is
produced by iHeartRadio. We would love to hear from you,
We really would.
Speaker 1 (48:35):
We want to know what questions you have about this
Extraordinary Universe.
Speaker 3 (48:40):
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