How Fluoroscopy (X-Ray) Works

If a Genie from a lamp told you to choose
any superpower, which would you ask for? Me? I’d have take X-ray vision. Seriously, if you can see through people,
what else could you possibly need? But I doubt that even a Genie can put an X-ray
mechanism into my eyes. It’s all about physics, after all. Inside a fluoroscopy machine that looks through
your body as if it were a glass, there is a Crookes tube. It’s a device with 2 electrodes – metal
current-carrying conductors. The cathode is attached to a negatively charged
source of current, the anode is attached to a positively charged source. Negatively charged electrons that come off
the cathode gain speed and bump into the positively charged anode, where they have to pull up
sharp. As a result of this, there appears an X-ray. Just as simple as that. Uh huh. X-ray electrons coming through a material
can either diffuse or absorb, which leads to their slowing. The harder the material is, the slower they
will move. That’s why human bones that are hard because
of much calcium in them slow down X-rays much more than soft tissues that are 70% water. Air lets them go without any obstacles. The way X-rays go through tissues gets fixed
on the photographic plate as shades of different intensity: the more solid the tissue is, the
more intense the color on the plate will be. White spots for bones, grey spots for tissues,
and black ones for air. In fact, X-ray pictures are photo negatives,
that’s why lighter spots are called “shadows”. Assume healthy lungs full of air look black
on an X-ray picture. A swollen spot of pneumonia will look like
a lighter spot, but doctors will say that it’s a shadow. A hundred years ago an opportunity to literally
look through a person would seem crazy to scientists and doctors. In fact, the father of X-rays, German physicist
Wilhelm Roentgen, discovered them by accident. On November 8, 1895, Roentgen stayed in his
laboratory till late at night. When he was going to leave and turned off
the light and all the devices he noticed that a bottle with transparent liquid in one of
the corners of the laboratory started shining with a green light. Roentgen noticed that he’d forgotten to
turn off a vacuum tube. After he turned it off the light disappeared. He got interested in an unusual effect and
started researching his casual discovery. As the bottle stood in the opposite corner
from the tube it meant that the tube was sending out an invisible ray. To check its qualities, the scientist would
put different things in its way – a sheet of paper, cardboard, a glass, and even wood
boards. The ray could go through all of them without
any difficulty. But when he put there a box with metal weights
Roentgen saw their clear-cut silhouette on the wall. He went on and accidentally his hand also
got under the strange ray. What Roentgen saw shocked him – he saw the
shade of his hand’s bones! He literally was looking through his hand. To record the effect of X-rays Roentgen added
a photographic plate to the construction and several days after his casual discovery he
made the first X-ray picture in history – it was his wife Bertha’s hand. Roentgen realized that he’d found a new
kind of rays that were invisible to a human eye but could light up anything. He called them X-rays. But it’s not that he considered himself
a genius after that. When he was offered to patent his invention,
he burst out laughing. He was skeptical about X-rays as he saw no
sphere where they could be used. He just kept experimenting putting all kinds
of materials in the way of X-rays. This is how he found out that lead was the
only material that did not let them pass through at all. That’s why we still use lead to protect
ourselves from radiation. Despite his own attitude towards his discovery,
it made a sensation in the scientific community, and the units to measure the amount of X-rays
were named after him — Roentgen. He was the first scientist in history to receive
a Nobel prize in physics but he never patented his invention and granted it to people. It allowed some go-getters to use Roentgen’s
discovery for their profit. They would open medical offices where anyone
could get a picture of their skeleton. One of the newspapers of the time printed
an article that claimed that X-rays could turn lead into gold. Well, though X-rays were not that magical,
doctors around the world soon appreciated the value of Roentgen’s invention. They started using X-ray machines to diagnose
bone breaks already in 1896. More than a hundred years have passed since
X-rays were discovered in 1895, but it is still considered one of the most serious breakthroughs
in medicine. X-rays allowed to diagnose many serious diseases
simply and precisely. It’s hard to imagine now, but before X-rays
were discovered, doctors had no way to look inside a human body without an operation. Granted, it made the process of treatment
much more difficult, and some diseases were impossible to diagnose altogether. That’s why patients could not rely on medicine
very much at the time, and doctors in their turn could give no guarantees. X-ray machines have become more sophisticated
since then but the principle of their work remains the same. It was not until the second half of the 20th
century that X-ray technology was considered not totally safe as it exposes you to radiation. Its effect is different in different body
parts. Say, the radiation dose you’ll get from
chest fluoroscopy is equal to the dose you’ll get in 10 days just walking in the street. The dose of hand fluoroscopy is the same as
you’ll get in 1 day in the street. The dose of stomach and intestine X-rays is
equal to what you can get in 3 years of your common life. That said, it is still a unique and useful
method that helps to make a correct diagnosis but should be only used when necessary. Here’s one more thing to show that you shouldn’t
fear it. We get much more radiation daily just during
our routine. The Sun is the greatest source of radiation
that tries to get to us from space. We are well protected from extra doses by
the Earth’s electromagnetic field and its atmosphere, yet still some part of it gets
through – the higher above the ground, the more. But it does not hurt us, our bodies are well
adapted for it. For the last century X-rays got used not only
in medicine. Airport services also use their amazing qualities. They have to X-ray not only passengers’
luggage but also parcels sent by post. Before parcels and letters get on board the
plane they go through a radiograph machine which shows their content on the screen. If the employees see anything suspicious or
forbidden for post-delivery inside parcels, they will take them off the plane. Airplanes themselves are x-rayed too. It allows noticing tiny breaks and scratches
on the plane’s skin. They are invisible to human eye but could
lead to more serious damage if left without repair. The most unusual area where X-rays are used
now is expert evaluation of the authenticity of art pieces. This method was used for the first time 70
years ago and is still the most reliable one. Even if the original picture and its copy
look the same, X-rays will show which one is false. They help to see how the artist laid colors
on the canvas, which technique he used and how many layers of paint there are on the
canvas. All these things allow professionals to tell
the original picture from the copy very easily. X-rays are now widely used in archeology too. When they found scrolls in Pompeii, they were
so fragile that any attempt to unfold them would ruin them forever. But X-rays helped to read the text written
inside the scrolls without unfolding them! It is a unique example of how a physical method
is widely used in life. Hey, if you learned something new today, then
give the video a like and share it with a friend! And here are some other cool videos I think
you’ll enjoy. Just click to the left or right, and stay
on the Bright Side of life!


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