I. Introduction
A wave is a disturbance of some property of a medium, for example,
density, pressure, electric field or magnetic field, which propagates through space, carrying energy
. The medium may be disturbed diverse in nature as air, water,
a piece of metal or ultra high vacuum space. Note the existence of a number of
wave phenomena, which are the effects and properties exhibited by the physical entities that propagate
waveform. These are:
· Diffraction - occurs when a wave to run into the edge of an obstacle
stop going in a straight line to go around. • Effect
Doppler - Effect due to movement between the power station on the
waves and receiver thereof.
·
Interference - Occurs when two waves combine to found at the same point
space. 
Interference - Occurs when two waves combine to found at the same point
· Reflection - occurs when a wave, when encountering a new medium that can not cross
change of direction.
· Refraction - occurs when a wave changes direction when entering a new environment in which
travels at different speeds.
· Shockwave - occurs when several waves traveling in half
overlap forming a cone.
The frequency of sound is the number of times wave
through the same point in a second. It is measured in cycles per second or hertz (Hz). The frequency range of audible sound
is 20 Hz to 25 000 Hz Hz multiples are the kilohertz (1000 Hz) or
the megahertz (1,000,000 Hz). The diagnostic utility of the sound begins
ascertainable from the megahertz. Thus the frequencies used in medicine range from 1 to 10 MHz
Ultrasound is an acoustic wave whose frequency is above the limit
perceptible by the human ear (approximately 20 KHz). Many animals such as dolphins and bats
use it more like the radar in its orientation. This phenomenon is known
as echolocation. It is that the waves emitted by these
animals are so high that "bounce" easily into all objects around them, this makes
create an "image" and are directed where they are.
Ultrasound is used both in industrial applications (measuring distances
, internal characterization of materials, nondestructive testing, etc.), as
medicine, and this is where we focus.
II. Wave application in medicine
In the medical field is called the ultrasound equipment to devices such as
fetal doppler, which uses ultrasound waves 2 to 3 MHz to detect
fetal heart rate in the womb. They are also used in detecting brain tumors
(ecoencefalografía) and other parts of the body. Ultrasound imaging,
also called ultrasound scanning or sonography, involves exposing part of the body
high frequency sound waves to produce images inside the body.
Ultrasound exams do not use ionizing radiation (x rays).
Because ultrasound images are captured in real time, can show the structure and movement
internal organs of the body, as well as blood flowing through
blood vessels.
use of ultrasound in pregnant women
Sound waves reflected by different parts of the uterus of a pregnant woman
are different depending on the tissue with which they are located.
examination by ultrasound has many applications in pregnancy, allowing
answers to a series of medical concerns. Some of the most important questions that ultrasound can clarify
are:
-Ectopic pregnancy. Ultrasound can be used to diagnose the embryo is developing
out of place, usually in a fallopian tube or
abdomen instead of uterus.
-More than one baby. Ultrasound is used to see if a woman has twins, triplets and
including an even larger number of fetuses.
-Check the due date. The size of the fetus, which can be measured using ultrasound
, allows doctors to estimate the birth date accurately.
-evaluate fetal growth. As the fetus grows slower or faster than expected
, ultrasound can help determine the reason, such as excess 6el
amniotic fluid or poor fetal growth.
-Possibility of spontaneous abortion. When there is bleeding or bleeding at
early pregnancy or when the heartbeat or fetal movements
seem to have stopped, ultrasound can help determine if the fetus has died and the woman lost her baby
.
-help perform other prenatal diagnosis. When it is necessary to perform an analysis
amniocentesis or chorionic villus, doctors use ultrasound to guide
way to extract the cells needed to prove the existence of certain birth defects
.
Diagnose certain birth defects. Ultrasound images can
used to diagnose certain birth defects body structure, as
limbs and sometimes the absence of cleft lip and spina bifida.
may also allow the diagnosis of malformations of certain internal organs, including the urinary tract. A special ultrasound
called echocardiography permits to record
blood flow through the chambers and valves of the heart and blood vessels, allowing
detection of many congenital heart abnormalities also potentially dangerous heart rhythm
.
-Check the welfare of the fetus in late pregnancy through a test called
fetal biophysical profile (in English, "Fetal Biophysical profile"). This test is performed using ultrasound
and in addition to proof of "non-stress" (a special test of the beating fetal heart
usually done when the mother has diabetes or high blood pressure, or when it has passed
the estimated date of delivery). The ultrasound findings made
include visualization of fetal movements, their movements
breathing, muscle tone and measuring the amount of amniotic fluid.
-Helping to choose the method of delivery. Ultrasound can contribute significantly
determine what pregnancy will require a cesarean
intervention (also called a "C-section), such as when the fetus is
especially large or is in an abnormal position, or when the placenta is blocking the exit
Baby the uterus.
The ultrasound allows the investigation of almost all human
body components, however is most often used for monitoring pregnancy and
study of abdominal and pelvic organs in both men and women. Lithotripsy
The shock wave lithotripsy is a treatment that helps to expel the calculation
making gravel which are easier to remove. This treatment is called lithotripsy also
extracorporeal shock wave (ESWL for its acronym in English). The
procedure takes about an hour and can be performed in a hospital or in a facility or mobile unit
lithotripsy.
Echocardiography is a test that uses sound waves to create a moving picture of heart
. The picture is much more detailed than X-ray image and involves no radiation exposure
.
A trained sonographer performs the test, then the doctor interprets the results
. Is placed instrument that transmits high frequency sound waves, called
transducer in the ribs near the breast bone and directed toward the heart. This device collects echoes
waves and transmits them as electrical impulses.
The echocardiography machine converts these impulses into moving pictures of the heart.
Echocardiogram works well for most patients and allows doctors
see the heart beating and to visualize many of the structures of the heart.
Occasionally, your lungs, ribs, or body tissue may prevent
sound waves and echoes from providing a clear picture of heart function, and if so,
the sonographer may inject a small amount of contrast material through an intravenous
to better see inside the heart.
Rarely, you may need a more invasive testing using special
echocardiography probes.
If the echocardiogram is unclear due to a barrel chest, congestive obstructive pulmonary disease
or obesity, your doctor may choose to perform a transesophageal echocardiogram, or TEE
. With this procedure, it numbs the back of the throat and
an endoscope through it. At the tip of
scope is an ultrasonic device that an experienced guide to the lower esophagus, which is the
place where you usually get a two-dimensional echocardiogram of the heart more clearly. Medical Encyclopedia
and my collaboration
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