Lasers in Modern Medicine Starting time

A laser is a device that makes a beam of light so narrow and strong that it can cut
like a knife. (LASER stands for Light Amplification by the Stimulated Emission of
Radiation.) When it was invented, no one knew that it would change modern
medicine. But now, with this wonderful tool, doctors can safely perform operations
and treatments that were once very dangerous or painful, or simply impossible with
regular surgical instruments.
The first person to imagine something like a laser was Albert Einstein in 1917. He
realized that it might be possible to create a very strong, bright beam of light by
changing the way light acted. However, he never investigated this idea any further
and neither he nor anyone else tried to produce a laser beam for many years.
Finally, in the late 1950s, scientists began experimenting with light and figured out
how to create the strong beams we now know as laser beams. In these first
experiments, they used 288 Reading Faster mirrors and artificial gem stones to
change the light. Other scientists soon were producing the same results by sending
light through special gases. The light created by either of these methods was very
different from normal light. The beams from lasers remain narrow and do not spread
out as light normally does, even over great distance. Furthermore, laser beams can
be created entirely of one color, while normal light, such as that from a lightbulb,
contains a combination of all the colors.
In the early years after the invention of lasers, scientists called them "a solution
looking for a problem." It was obvious that lasers were very special, but it took
scientists a while to find practical applications for them. Over time, hundreds of
uses have been found for lasers in many areas of science and technology. They are
used in the newest telecommunication systems, in computer printers, and in
compact disc players. They are also used in show business to create special lighting
effects. But where lasers have made the most difference is undoubtedly in the world
of medicine, where they can be used for many tasks that require fine precision.
First, doctors can use lasers as cutting tools. Surgeons prefer lasers to surgical
knives for certain operations because laser beams can be made much narrower
than a knife blade. Also, with lasers, doctors can work more quickly than with metal
tools, and so there is less risk of infection. Furthermore, a laser beam produces
heat, which helps to close off the skin or tissue being cut into and reduces bleeding.
Thus, lasers have proved extremely useful in the fine surgery required to
reconstruct veins and arteries. They are also used in surgery to remove certain
kinds of brain or liver cancers. Doctors are experimenting with ways to find cancer
in various parts of the body through the use of a colored liquid that colors only the
cancerous areas. Then they can use lasers designed for that color to find the
cancer and burn it away. This removes the disease from the body but damages
nothing else.
Lasers have also dramatically changed the work of eye doctors. Poor vision is one of
the most common medical problems in the world, and until recently the only way to
correct it was with eyeglasses or contact lenses. Now many vision problems can be

corrected permanently with laser surgery. This surgery has made an enormous
difference for people who were practically blind without their glasses or contact
lenses. After a lifetime of worrying about breaking or losing their glasses or lenses,
they can see normally without them.
For eye surgery, doctors need to be extremely precise and extremely quick. They
use what is known as a cool laser, which produces beams that can cut out 39
millionths of an inch of tissue in 12 billionths of a second. In other words, this kind of
laser is so precise it could cut into a strand of hair without cutting all the way
through. In vision surgery, these lasers are used on a part of the eye called the
cornea, which is the transparent covering on the outside. When the cornea is not
perfectly round, we cannot see clearly. To improve vision, the doctor shapes the
cornea with a laser until it is more round. The process takes only a few minutes and
because the laser is cool, there is little pain.
Another use of lasers in medicine is for the removal of marks on the skin. In the
case of cancerous growths, laser beams can be used with far more precision than
knives or other tools. A laser beam with its one color of light can be directed to find
one color within the skin and destroy only the skin of that color. Some people are
born with large dark red marks on their face, for example, which can cause
embarrassment and psychological problems. With a dark red laser beam, doctors
can remove that mark. In recent years, doctors have also developed ways to use
laser beams to make people look younger by removing wrinkles around the mouth
and eyes. In all of these skin operations, the laser is able to work on just the top
layers of skin, causing much less pain and skin damage and with less risk of
infection or damage than what would be caused by other kind of tools.
It has been fifty years since lasers were first invented and were seen as a solution
looking for a problem. Now they are solving many problems in the world around us,
in technology and above all, in medicine. They have become essential tools for
scientists and doctors as they perform lifesaving operations and improve the quality
of our lives.
Choose the correct answers:
I. Choose the statement that best expresses the overall thesis of the
passage.
a. Lasers are used in many kinds of medical operations.
b. Scientists have found many uses for lasers in technology.
c. Eye surgery has changed dramatically with the use of lasers.
d. Laser light beams were first produced in the 1950s.
2. Albert Einstein
a. believed it was not possible to produce a laser beam.
b. was the first person to produce a laser beam.

c. imagined a laser beam, but never produced one.

d. experimented with laser beams as early as 1917.
3. Laser beams always contain all the colors, like normal beams of light.
a. True
b. False
4. Scientists realized that laser beams were special, but
a. Einstein thought it was not possible to use them.
b. they also thought they might be dangerous.
c. they did not know what to do with them at first.
d. doctors did not want to use them at first.
5. One reason why doctors use lasers in surgery is because they
a. allow doctors to see what they are doing.
b. create interesting lighting effects.
c. cost less than metal tools.
d. are more precise than metal tools.
6. Poor vision
a. improves only temporarily with laser surgery.
b. can be corrected permanently with laser surgery.
c. must be corrected by glasses and lenses.
d. can be corrected only in young people.
7. Doctors use laser beams to make people look younger.
a. True
b. False
8. You can infer from this passage that compared with the past more
a. people are having surgery to change the way they look.
b. people are getting cancer of the brain or the liver.
c. doctors are specializing in eye surgery and vision problems.
d. doctors are using traditional methods to correct vision problems.