Amanda Sabatelle
Boston University Summer Term 11
August 7, 2002
Physics: Narain
The Applications of Ultrasonics
Ultrasonics is the study and application of the energy of sound waves vibrating at frequencies greater then 20,000
cycles per second, or in other words, beyond the range of human hearing. The application of sound energy in the
audible range is limited almost entirely to communications. This is because increasing the pressure of sounds also
increases loudness, and therefore causes the discomfort to human beings. However because ultrasonic waves are
inaudible, they have little or no effect on the ear at even high intensities. Therefore, how do we use these inaudible
waves in the world of medicine and more generally in our daily life?
Medical ultrasonic devices are readily used to examine a human's internal organs without surgery. These procedures are
overall safer to one's genetic material than routine X-rays. For example, sonography, a technique that uses sound waves
to study and treat hard-to-reach body areas helps mothers learn the age, sex, and level of development of their fetus.
This testing also determines the presence of birth defects or other potential problems. Ultrasonic devices are used in
cardiology to detect heart damage and in ophthalmology to detect retinal problems. They are also used to heat joints,
relieving arthritic joint pain and in procedures such as lithotripsy in which shock waves break up one's kidney stones,
eliminating the need for surgery.
In addition to the many medicine-orientated applications of ultrasonics, these waves are even used in our day-to-day
life. For instance, ultrasonic nozzles, compared with conventional pressure spray nozzles, deliver a low-velocity spray.
These spray bottles can dispense small amounts of spray into a substrate repeatedly. Another domestic use includes a
phenomenon called cavitation, where a detergent solution and ultrasonic waves cause larger numbers of invisible
bubbles. This foamy substance explodes with great force on the surface of objects, removing film, dirt, and oil. Lastly,
engineers use ultrasonics to join plastics and metals. These products can be welded together by placing their surfaces in
contact with each other and initiating the connection of ultrasound. The molecules are then stimulated and rearranged
into crystalline forms.
Ultrasounds noninvasive products involve no radiation and clean like no other creation. The waves avoid the possible
hazards of surgery such as bleeding, infection, and reactions to chemicals and also welds metal faster than any other
machine. Consequently, the study of ultrasonics is continuously blossoming, and the safe and effective results of
ultrasonic devices attract more and more people as the daily uses of these waves are blossoming even more by leaps
and bounds. Hopefully, the uses of these products will continue to grow as the research behind these waves continues
to develop.
Greg Re
Ultrasound is a rapidly-growing technology that is being used in many different fields today. Ultrasound was originally
developed during World War 11 to help locate objects, such as submarines, submerged in water. Ultrasound relies on
sending out sound waves. Today there are many uses for ultrasound, and many more are being developed each day.
Ultrasound is now being used as a research tool on cattle carcasses. The cattle industry is developing ways to use gather
information and data regarding beer tenderness and quality. This information is used in studies that will be useful when
selecting cattle in the future to be slaughtered for beef. Ultrasound provides a reliable method of estimating the body
composition of cattle without causing damage to the carcass. These ultrasound techniques are more reliable and more
economical than progency testing, which was a popular technique used in the past. Recent studies indicate that
ultrasound can even be used on live cattle to help people predict the optimal slaughter end point.
Ultrasonography is also becoming widely-used in many surgical practices on humans. Ultrasonography is an effective,
non-evasive way to evaluate organ systems and to target intervention areas. The technique involves transmitting high-
frequency sound waves to areas of that body that are difficult to reach and recording the returning echoes. Ultrasound is
now being used in medical evaluations of the eye, neck, reproductive organ systems, the vascular system, the nervous
system, and the musculoskeletal system. Cardiologists use it to detect and locate damage to the heart. Opthamologists
use it to detect retinal problems. Almost every branch of medicine can utilize ultrasound is someway.
Ultrasound is now being used to track the development of fetuses. This has many uses. Ultrasound can be used to
predict potential birth defects or other health problems in the fetus. It can also be used to determine the age, sex, and
size of the fetus.
Besides being used to locate health problems, ultrasound is used to treat some health problems as well. It can be used to
heat joins, which relieves pain often caused by arthritis. Ultrasound is used in a process known as lithotripsy.
Lithotripsy is used to break apart kidney stones. The use of lithotripsy can often times eliminate the need for surgery.
Ultrasound has many benefits. Besides being much more affordable and reliable than other techniques, it is nonevasive. There is no radiation involved with ultrasound. Side effects of other treatments, including infections, bleeding,
and allergic reactions, can be serious drawbacks.
Eric Hansen
Ultrasonic sound waves have many purposes, and one that is just being explored, identity verification. Researchers are
developing a camera that uses ultrasonic waves to capture a person's fingerprint and compare it to a fingerprint on file.
The software for this already exists for fingerprint identification, comparing a fingerprint with one on file, so only the
software for capturing the fingerprint will have to be created. As far as safety goes, the fingerprint scan can be made
into a button, and the amount of time that one presses that button is how long the scan takes, so it is ergonomically
sound. The captured fingerprint is so highly defined that it can detect most artificial fingers and other devices of
identity theft.
To use this device, the finger is pressed up against the camera, and ultrasonic waves are released from an electroacoustic transistor, and when the waves echo off of the fingerprint, they are sent back to the camera, and subsequently
to an attached computer for processing. The receiver inside of the camera rotates to capture all of the results and
reduced by a 50-megahertz scope. The image of a fingerprint without analysis by a computer is distorted, because the
camera detects objects on a two-dimensional plane, while the human finger is a three-dimensional plane. Through
reconstruction processes, the fingerprint can be edited through a certain mathematical equation, producing a reasonably
recognizable image of a fingerprint, although enhancement is necessary to produce a correct image. This enhancement
requirement is created by electronic interference, and other noises. After enhancement, which can consist of
deconvolution of the echo, and also smoothing and binearization techniques are employed.
The amplitude of the waves echoed back to the camera can define a fake finger from a real finger, due to the difference
in amplitude, caused by the difference in substance. In addition, dirt, oil, water, and other contaminates does not affect
the output of the fingerprint scan, which makes this a practical solution to identity verification. Lingering fingerprints
from past scans are not detected by the camera, or can be filtered out because the fingerprint itself produces an echo 30
dB lower than that of a live finger. For practicality, also, metal powder, ink, and soot are not required by the camera to
detect the finger print, because they also produce echoes which are not consistent with that of a real finger, and the
ultrasonic waves can detect fingerprint without extra assistance that other methods require.
The use of ultrasonic waves for the purpose of identity verification via fingerprint identification is a practical, and soon
possible source of this information. The ultrasonic waves are not impacted by any visual impediments; such as dirt, oil,
water, soot, etc. and only because of electronic interference within the camera slight enhancements are required. These
systems are much more practical than the systems in place now because of their vulnerability to error, due to fraudulent
finger prints and dirtiness of the subject being tested. As more testing and enhancement of the camera occur, the
availability of this device will increase.
Boston Summer Challenge
Physics
Ruchi Jain
8/5/02
THE USE OF ULTRASOUND: A MEDICAL PERSPECTIVE
There are many different medical uses for the ultrasound. Ultrasound is a medical imaging system, which uses sound
waves with very high frequencies and their corresponding echoes. The machine transmits frequencies varying from 1-5
megahertz into one's body and hits boundaries between tissues. While some waves are immediately reflected back to
the probe, others travel further where they encounter more boundaries and eventually are reflected back as well. These
reflected waves then travel from the probe back to the machine that then calculates the distance from the probe to the
tissue or organ. It does this by using the speed of sound in tissue (5,005 ft/s or 1,540 m/s) and the time of the return of
each echo. The machine depicts the distances and intensities of the echoes on the screen then forming a twodimensional image. The probe can be moved along the surface of the body and angled to receive different views.
Obtaining images of young fetuses is one of the most common uses of the ultrasound in medicine. It determines the due
date by finding out the size of the fetus and determines the location of the fetus to see if it is in the normal head down
position or in another position. It checks to see the number of fetuses in the uterus and also determines the sex of the
baby if possible from the position the baby is in. It determines the baby's growth rate and accomplishes this by making
many measurements over a period of time. It determines the amount of amniotic fluid supporting the baby and can tell
if there is not enough fluid inside. It can detect ectopic pregnancy, a condition in which the baby is implanted not in the
uterus, but instead in the fallopian tubes. This life-threatening situation can be diagnosed in an early stage and treated
by the use of ultrasound. Ultrasound has also helped reduce the risks of amniocentesis, a procedure that takes a
sampling of the amniotic fluid and one that was once done blindly when ultrasound was not available. It also depicts
any possible tumors in the breasts and ovaries.
Obstetric Ultrasound uses a slightly different procedure than normal ultrasound. Real time scanners produce a
continuous picture of the moving fetus that is then depicted on a monitor screen. Very high frequency sound waves of
between 3.5 to 7.0 megahertz are generally used for this purpose. These high frequencies are transmitted from a
transducer, which is put in contact with the maternal abdomen, and is moved to look at any one part of the uterus. Rays
of ultrasound beams are repeatedly sent out to scatter the fetus into thin slices and are then reflected back onto the same
transducer. The information obtained from the various reflections are then put back together to form a picture on the
monitor screen. This picture is called a sonogram. Movements such as fetal heart beat and malformations in the fetus
can be evaluated and measurements can be obtained accurately on the images viewed on the screen. These
measurements can then be used to assess the aforementioned characteristics of the baby (size, gestation period, etc.)
As one can see the ultrasound is a very useful procedure often used in obstetrics to help produce images of a young
fetus. Ultrasound has helped many parents in not only saving their own lives, but also the lives of their unborn babies.