optsub majinven att ultrasound

8/6/2019 OptSub MajInven Att Ultrasound

1/7

ULTRASOUND IS THE MAJOR INVENTIONS IN THE 21ST

CENTURY

The term SONARrefers to Sound Navigation and Ranging. As early as 1822,

Daniel Colladen, a Swiss physicist, had used an underwater bell in an attempt tocalculate the speed of sound in the waters of Lake Geneva. Other early attempts at

mapping the ocean-floor basing on simple echo-sounding methods were neverthelessunrewarding. Lord Rayleigh in England published in 1877 the famous treatise "TheTheory of Sound" in which the fundamental physics of sound vibrations (waves),

transmission and refraction were clearly delineated. The breakthrough in echo-

sounding techniques came when the piezo-electric effect in certain crystals wasdiscovered by Pierre Curieand his brother Jacques Curie in France in 1880.

They observed that an electric potential would be produced when mechanical

pressure was exerted on a quartz crystal such as the Rochelle salt (sodium potassium

tartrate tetrahydrate) and conversely, the application of an electric charge wouldproduce deformation in the crystal and causing it to vibrate. It was then possible for the

generation and reception of 'ultra'-sounds that are in the frequency range of millions ofcycles per second (megahertz) which could be employed in echo sounding devices. Much

research and development in piezo-electricity followed.

Underwater detection systems were developed after the Titanicsank in 1912 and for the purpose of underwater navigation by submarines in

World War I. The first patent for under-water echo ranging sonar was filedat the British Patent Office by LF Richardson, one month after the sinking

of the Titanic. The first working sonar system was designed and built in the

United States by Canadian Reginald A Fessenden in 1914. The Fessendensonar could detect icebergs up to two miles away, and it was also used for signaling

submarines. Between 1914 and 1918 SONAR was in great demand for the detection ofGerman submarines in the waters.

Paul Langvin, an emminent French physicist in Paris, togetherwith Constantin Chilowsky, a Russian living in Switzerland, started to

develop a powerful ultrasonic echo-sounding device in 1915, which they

called the 'hydrophone', and formed the basis for the development of

medical pulse-echo SONAR in later years. By about the early 1930s, withthe developments from Langvin's laboratory, many French ocean liners

were equipped with underwater echo-sounding range display systems.

World war II saw further developments in naval and military radar (radiodetection and ranging, and using electromagnetic waves rather than ultrasound)

equipments, and faster electronics, which had facilitated enormously the design of

SONAR and ultrasonic detector devices in later years. Two other engineering advances

have also influenced significantly the development of SONAR: the first digitalcomputer (the Electronic Numerical Integrator and Computer -- the ENIAC) constructed

at the University of Pennsylvania in 1945, and the invention of the point-contact

transisterin 1947 at AT & T's Bell Laboratories.
http://www.ob-ultrasound.net/colladon.htmlhttp://www.ob-ultrasound.net/rayleigh.htmlhttp://www.measure.demon.co.uk/docs/Theory.htmlhttp://www.measure.demon.co.uk/docs/Theory.htmlhttp://www.piezo.com/history.htmlhttp://www.ob-ultrasound.net/curie.htmlhttp://www.ob-ultrasound.net/curie.htmlhttp://ice.chem.wisc.edu/materials/piezo.htmlhttp://collections.ic.gc.ca/heirloom_series/volume4/42-45.htmhttp://www.ob-ultrasound.net/chilo_lange.htmlhttp://www.ob-ultrasound.net/langevin.htmlhttp://www.ob-ultrasound.net/hydrophone.htmlhttp://www.ob-ultrasound.net/radar.htmlhttp://www.ob-ultrasound.net/radar.htmlhttp://ftp.arl.mil/~mike/comphist/eniac-story.htmlhttp://www.ob-ultrasound.net/transister.htmlhttp://www.ob-ultrasound.net/transister.htmlhttp://www.ob-ultrasound.net/colladon.htmlhttp://www.ob-ultrasound.net/rayleigh.htmlhttp://www.measure.demon.co.uk/docs/Theory.htmlhttp://www.measure.demon.co.uk/docs/Theory.htmlhttp://www.measure.demon.co.uk/docs/Theory.htmlhttp://www.piezo.com/history.htmlhttp://www.ob-ultrasound.net/curie.htmlhttp://ice.chem.wisc.edu/materials/piezo.htmlhttp://collections.ic.gc.ca/heirloom_series/volume4/42-45.htmhttp://www.ob-ultrasound.net/chilo_lange.htmlhttp://www.ob-ultrasound.net/langevin.htmlhttp://www.ob-ultrasound.net/hydrophone.htmlhttp://www.ob-ultrasound.net/radar.htmlhttp://ftp.arl.mil/~mike/comphist/eniac-story.htmlhttp://www.ob-ultrasound.net/transister.html


2/7

Another parallel and equally important development in

ultrasonic which had started in the 1930's was the construction ofpulsed-echo ultrasonic metal flaw detectors, particularly relevant

at that time was the check on the integrity of metal hulls of large

ships and the amour plates of battle tanks. The concept of ultrasonicmetal flaw detection was first suggested by Soviet scientist Serge YSokolov in 1928 at the Electro technical Institute of Leningrad.

Early pioneers of such devices were Floyd A Firestone at theUniversity of Michigan, and C H Desch and Donald Sproule in

England. Firestone produced his patented "supersonic reflectoscope" in 1941 (US-Patent

2 280 226 "Flaw Detecting Device and Measuring Instrument", April 21, 1942). Messrs.

Kelvin and Hughes in England, where Sproule was working, had also produced one ofthe earliest pulse-echo metal flaw detectors, the M1. Josefand Herbert Krautkrmer

produced their first German version in Kln in 1949. These were then quickly followed

by improved versions from Siemens of Germany (Lutsch bei Siemens) and

KretzTechnikof Austria.

Ultrasound Scans:

Obstetric Ultrasound is the use of ultrasound scans in pregnancy. Since itsintroduction in the late 1950s ultrasonography has become a very useful

diagnostic tool in Obstetrics. Currently used equipments are known as

real-time scanners, with which a continuous picture of the moving fetuscan be depicted on a monitor screen. Very high frequency sound waves of

between 3.5 to 7.0 megahertz (i.e. 3.5 to 7 million cycles per second) are generally used

for this purpose. They are emitted from a transducerwhich is placed in contact with the

maternal abdomen, and is moved to "look at" (likened to a light shined from a torch) anyparticular content of the uterus. Repetitive arrays of ultrasound beams scan the fetus in

thin slices and are reflected back onto the same transducer. The information obtained

from different reflections are recomposed back into a picture on the monitor screen (asonogram, or ultra sonogram). Movements such as fetal heart beat and malformations in

the feus can be assessed and measurements can be made accurately on the images

displayed on the screen. Such measurements form the cornerstone in the assessment ofgestational age, size and growth in the fetus.

Ultrasound used in Pregnancy: Ultrasound scan is currently considered tobe a safe, non-invasive, accurate and cost-effective investigation in the fetus. It

has progressively become an indispensable obstetric tool and plays an importantrole in the care of every pregnant woman.

The main uses of ultrasonography are in the following areas:1. Diagnosis and assessment of early pregnancy.

The gestational sac can be visualized as early as four and a half weeks of

gestation and the yolk sac at about five weeks.
http://www.ob-ultrasound.net/history.htmlhttp://www.ob-ultrasound.net/probes.htmlhttp://medicine.creighton.edu/radiology/ultraofearlypreg.html#anchor120896http://medicine.creighton.edu/radiology/ultraofearlypreg.html#anchor121578http://www.ob-ultrasound.net/history.htmlhttp://www.ob-ultrasound.net/probes.htmlhttp://medicine.creighton.edu/radiology/ultraofearlypreg.html#anchor120896http://medicine.creighton.edu/radiology/ultraofearlypreg.html#anchor121578


3/7

2. Threatened miscarriage: The viability of the fetus can be documented in the

presence of vaginal bleeding in early pregnancy. Fetal heart motion is usually clearly

depict able by 7 weeks. If this is observed, the probability of a continued pregnancy isgreater than 97 percent. Missed abortion and blighted ovum will usually give typical

pictures of a deformed gestational sac and absence of fetal poles or heart beat.

Ultrasonography is also indispensable in the early diagnosis of entopic pregnancies andmolar pregnancies.

3. Determination of gestational age and assessment of fetal size. Fetal body

measurements reflect the gestational age of the fetus. This is particularly true in early

gestation. In patients with uncertain last menstrual periods, such measurements must bemade as early as possible in pregnancy to arrive at a correct dating for the patient. In the

latter part of pregnancy measuring body parameters will allow assessment of the size and

growth of the fetus and will greatly assist in the diagnosis and management of

intrauterine growth retardation (IUGR).

The following measurements are usually made:

a) The Crown-rump length (CRL):This measurement can be made

between 7 to 13 weeks and gives very accurate estimation of the gestational

age. Dating with the CRL can be within 3-4 days of the last menstrualperiod.

b) The Biparietal diameter (BPD): The diameter between the 2 sides of the head. This is measured after 13 weeks. It increases from about 2.4 cm at 13 weeks to

about 9.5 cm at term. Different babies of the same weight can have different head size,

therefore dating in the later part of pregnancy is generally considered unreliable.

c) The Femur length (FL): Measures the longest bone in the body and reflects

the longitudinal growth of the fetus. Its usefulness is similar to the BPD. It increases fromabout 1.5 cm at 14 weeks to about 7.8 cm at term.

(d) The Abdominal circumference (AC):The single most important measurement to

make in late pregnancy. It reflects more of fetal size and weight rather than age. Serialmeasurements are useful in monitoring growthof the fetus.

The weight of the fetus at any gestation can also be estimated with great accuracyusing polynomial equations containing the BPD, FL, and AC. Lookup charts are readily

available. For example, a BPD of 9.0 cm and an AC of 30.0 cm will give a weightestimate of 2.85 kg.

4. Placental localization. Ultrasonography has become indispensable in the diagnosis

or exclusion of placenta previa, and other placental abnormalities as in diabetes, fetal

hydrops, Rh isoimmunization and severe intrauterine growth retardation .

5. Multiple pregnancies. In this situation, ultrasonography is invaluable indetermining the number of fetuses, the chorionicity, fetal presentations, evidence of
http://medicine.creighton.edu/radiology/ultraofearlypreg.html#anchor124162http://cpmcnet.columbia.edu/health.sci/.gcps/gcps039.htmlhttp://cpmcnet.columbia.edu/health.sci/.gcps/gcps039.htmlhttp://www.kenes.com/cogibook1999/Can_Ultrasound_Determine_Chorionicity_and_Amnionicity_in_Mutiple_Pregnancy.htmlhttp://www.kenes.com/cogibook1999/Can_Ultrasound_Determine_Chorionicity_and_Amnionicity_in_Mutiple_Pregnancy.htmlhttp://www.kenes.com/cogibook1999/Can_Ultrasound_Determine_Chorionicity_and_Amnionicity_in_Mutiple_Pregnancy.htmlhttp://medicine.creighton.edu/radiology/ultraofearlypreg.html#anchor124162http://cpmcnet.columbia.edu/health.sci/.gcps/gcps039.htmlhttp://www.kenes.com/cogibook1999/Can_Ultrasound_Determine_Chorionicity_and_Amnionicity_in_Mutiple_Pregnancy.html


4/7

growth retardation and fetal anomaly, the presence of placenta previa, and any suggestion

oftwin-to-twin transfusion.

6. Hydramnios and Oligohydramnios. Excessive or decreased amount of liquor(amniotic fluid) can be clearly depicted by ultrasound. In both these situations, careful

ultrasound examination should be made to exclude intraulterine growth retardation andcongenital malformation in the fetus such as intestinal atresia, hydrops fetalis or renal

dysplasia.

7. Fetal malformation. Many structural abnormalities in the fetus can be

reliably diagnosed by an ultrasound scan, and these can usually be made before 20

weeks. Common examples include hydrocephalus, anencephaly,

myelomeningocoele,achondroplasia and other dwarfism, spina bifida, exomphalos,duodenal atresia and fetal hydrops. With more recent equipments, conditions such

as cleft lips/palate, congenital cardiac abnormalities and Down syndrome are more

readily recognised. Markers for chromosomal abnormalities such as the fetal

nuchal translucency (the area at the back of the neck) have also been defined toenable detection of these abnormal fetuses. Ultrasound can also assist in other

diagnostic procedures in prenatal diagnosis such as amniocentesis, chronic villussampling,percutaneous umbilical blood sampling and in fetal therapy.

8. Other areas. Ultrasonography is of great value in other obstetric conditions such as:

a) Confirmation of intrauterine death.

b) Confirmation of fetal presentation in uncertain cases.c) Evaluating fetal movements, tone and breathing in the Biophysical Profile.

d) Diagnosis of uterine and pelvic abnormalities during pregnancy e.g. fibromyomata and

ovarian cyst.

The Schedule:

There is no hard and fast rule as to the number of scans a woman should have

during her pregnancy. A scan is ordered when an abnormality is suspected onclinical grounds. Otherwise a scan is generally booked at about 7 weeks to

confirm pregnancy, exclude entopic or molar pregnancies, confirm cardiac

pulsation and measure the crown-rump length for dating.A second scan is performed at 18 to 20 weeks to look for congenital malformations,

exclude multiple pregnancies and to verify dates and growth. Placental position is also

determined. A third scan may sometimes be done at around 34 weeks to evaluate fetal

size and assess fetal growth. Placental position is verified. Many centers are now doing ascan at around 13-14 weeks to measure the nuchal skin fold thickness for the purpose of

evaluating the risk forDown syndrome. What is often referred to as a Level II scan

merely indicates a "targeted" examination where it is done when an indication is presentor when an abnormality is suspected in a previous examination. In fact professional

bodies such as the American Institute of Ultrasound in Medicine do not endorse or

encourage the use of these terms. A more "thorough" examination is usually done at aperinatal center or specialized clinic where more expertise and better equipments may be
http://www.tttsfoundation.org/http://www.cpdx.com/cpdx/abcns.htmhttp://www.cpdx.com/cpdx/abcns.htmhttp://www.icondata.com/health/pedbase/files/MYELOMEN.HTMhttp://www.icondata.com/health/pedbase/files/ACHONDRO.HTMhttp://www.stanford.edu/~holbrook/Spinabifida.htmlhttp://www.cpdx.com/cpdx/abdwall.htmhttp://www.cpdx.com/cpdx/abdwall.htmhttp://www.peds.umn.edu/divisions/neonatology/tfiles/hydrops.htmlhttp://www.med.upenn.edu/fetus/fetex2.htmhttp://www.ob-ultrasound.net/xdown.htmlhttp://home.wxs.nl/~faase009/nuchalfold.htmlhttp://home.wxs.nl/~faase009/nuchalfold.htmlhttp://www.stanford.edu/~holbrook/Amniocentesis.htmlhttp://www.stanford.edu/~holbrook/CVS.htmlhttp://www.stanford.edu/~holbrook/CVS.htmlhttp://www.stanford.edu/~holbrook/PUBS.htmlhttp://www.fetalmd.com/http://medicine.creighton.edu/radiology/Ultraoffetalwellbeing.html#anchor298327http://www.ob-ultrasound.net/xdown.htmlhttp://www.tttsfoundation.org/http://www.cpdx.com/cpdx/abcns.htmhttp://www.cpdx.com/cpdx/abcns.htmhttp://www.icondata.com/health/pedbase/files/MYELOMEN.HTMhttp://www.icondata.com/health/pedbase/files/ACHONDRO.HTMhttp://www.stanford.edu/~holbrook/Spinabifida.htmlhttp://www.cpdx.com/cpdx/abdwall.htmhttp://www.cpdx.com/cpdx/abdwall.htmhttp://www.peds.umn.edu/divisions/neonatology/tfiles/hydrops.htmlhttp://www.med.upenn.edu/fetus/fetex2.htmhttp://www.ob-ultrasound.net/xdown.htmlhttp://home.wxs.nl/~faase009/nuchalfold.htmlhttp://home.wxs.nl/~faase009/nuchalfold.htmlhttp://www.stanford.edu/~holbrook/Amniocentesis.htmlhttp://www.stanford.edu/~holbrook/CVS.htmlhttp://www.stanford.edu/~holbrook/CVS.htmlhttp://www.stanford.edu/~holbrook/PUBS.htmlhttp://www.fetalmd.com/http://medicine.creighton.edu/radiology/Ultraoffetalwellbeing.html#anchor298327http://www.ob-ultrasound.net/xdown.html


5/7

present. One should not dwell too much on the definitions orguidelines for a level II

ultrasound scan. The sonologist should always try very hard to look for and assess any

abnormality that may be present in the fetus. It is not very meaningful to be talking aboutlevel III or even level IV scans.

Transvaginal Scan: With specially designed probes, ultrasound scanning can be done withthe probe placed in the vagina of the patient. This method usually provides better images (andtherefore more information) in patients who are not pregnant or are in the early stages of

pregnancy. Fetal cardiac pulsation can be observed as early as 6 weeks of gestation. Vaginal

scans are becoming indispensible in the early diagnosis of entopic pregnancies. An increasing

number of fetal abnormalities are now being diagnosed in the first trimester using the vaginal

scan. Transvaginal scans on the other hand are also useful in the second trimester in the diagnosis

of congenital anomalies. Readoneof my presentations atOBGYN.net-Ultrasound.

Doppler Ultrasound:The doppler shift principle has been used for a long time infetal heart rate detectors. Further developments in doppler ultrasound technology in

recent years have enabled a great expansion in it's application in Obstetrics, this time in

the area of assessing and monitoring the well-being of the fetus. Blood flowcharacteristics in the fetal blood vessels can be assessed with Doppler 'flow velocity

waveforms'. Diminished flow, particularly in the diastolic phase of a pulse cycle is

associated with compromise in the fetus. Various ratios of the systolic to diastolic flow

are used as a measure of this compromise. The blood vessels commonly interrogated

include the umbilical artery, the aorta, the middle cerebral arteries and the uterine

arcuate arteries. The use of color flow mapping can clearly depict the flow of blood in

fetal blood vessels in a real-time scan, the direction of the flow being represented by

different colors. 'Color' Doppler is particularly indispensable in the diagnosis and

assessment of congenital heart abnormalities. Another recent development is the Power

Doppler (Doppler angiography). It uses amplitude information from Doppler signalsrather than flow velocity information to visualize slow flow in smaller blood vessels. A

color perfusion-like display of a particular organ such as the placenta overlapping on the2-D image can be very nicely depicted. Doppler examinations can be performed

abdominally and via the transvaginal route. The power emitted by a Doppler device is

generally greater than that used in a conventional 2-D scan.

Color imaging: This is a recent addition to plain 2-D realtime scanning.

Also known as "chroma" scans, user-selectable color hues are assigned

to the shades of grey for better visualization of subtle tissue details. This

clever enhancement is aimed at better interpretation of the scans. 'Color

scans' do not imply that various parts of the same picture are depicted in

different colors like what we see in a color photograph.

3-D Ultrasound: 3 dimensional ultrasound is quickly moving out of theresearch anddevelopment stages and is very much in the News. Faster and more advanced

commercial models are coming into the market. The scans require special probes

and software to accumulate and render the images, and the rendering time has been reduced from minutes to seconds. A good 3D image is often quite

impressive and further 2D scans may be extracted from 3D blocks of scanned
http://www.ob-ultrasound.net/joewoo3.html#8ahttp://www.ob-ultrasound.net/images/scanvag.jpghttp://health.excite.com/content/asset/adam_test_transvaginal_ultrasoundhttp://www.ob-ultrasound.net/images/us26.jpghttp://radiology.creighton.edu/Milestones-Ectopic-Preg.htmlhttp://www.obgyn.net/us/cotm/9810/cotm_9810.htmhttp://www.obgyn.net/us/cotm/9810/cotm_9810.htmhttp://www.obgyn.net/us/cotm/9810/cotm_9810.htmhttp://www.obgyn.net/us/us.htmhttp://www.obgyn.net/us/us.htmhttp://liley.physics.swin.oz.au/~dtl/sp407/doppler/node1.htmlhttp://www.ob-ultrasound.net/xdopwave.htmlhttp://www.ob-ultrasound.net/xdopwave.htmlhttp://www.ob-ultrasound.net/xdopwave.htmlhttp://www.ob-ultrasound.net/images/caorta.jpghttp://www.ob-ultrasound.net/images/caorta.jpghttp://ej.rsna.org/ej3/0079-98.fin/doppler.htmhttp://ej.rsna.org/ej3/0079-98.fin/doppler.htmhttp://ej.rsna.org/ej3/0079-98.fin/doppler.htmhttp://www.ob-ultrasound.net/images/gastro.jpghttp://www.ob-ultrasound.net/images/gastro.jpghttp://www.fetal.com/uspict2.htmhttp://www.ob-ultrasound.net/voluson.htmlhttp://www.ob-ultrasound.net/voluson.htmlhttp://www.ob-ultrasound.net/voluson.htmlhttp://www.ob-ultrasound.net/news3d.htmlhttp://www.worldnet.net/~henrib/PageMill_Images/Echo/sonde2.jpghttp://www.worldnet.net/~henrib/3D_ultra.htmlhttp://www.ob-ultrasound.net/joewoo3.html#8ahttp://www.ob-ultrasound.net/images/scanvag.jpghttp://health.excite.com/content/asset/adam_test_transvaginal_ultrasoundhttp://www.ob-ultrasound.net/images/us26.jpghttp://radiology.creighton.edu/Milestones-Ectopic-Preg.htmlhttp://www.obgyn.net/us/cotm/9810/cotm_9810.htmhttp://www.obgyn.net/us/us.htmhttp://liley.physics.swin.oz.au/~dtl/sp407/doppler/node1.htmlhttp://www.ob-ultrasound.net/xdopwave.htmlhttp://www.ob-ultrasound.net/xdopwave.htmlhttp://www.ob-ultrasound.net/images/caorta.jpghttp://ej.rsna.org/ej3/0079-98.fin/doppler.htmhttp://ej.rsna.org/ej3/0079-98.fin/doppler.htmhttp://www.ob-ultrasound.net/images/gastro.jpghttp://www.fetal.com/uspict2.htmhttp://www.ob-ultrasound.net/voluson.htmlhttp://www.ob-ultrasound.net/voluson.htmlhttp://www.ob-ultrasound.net/news3d.htmlhttp://www.worldnet.net/~henrib/PageMill_Images/Echo/sonde2.jpghttp://www.worldnet.net/~henrib/3D_ultra.html


6/7

information. Volumetric measurements are more accurate and both doctors and

parents can better appreciate a certain abnormality or the absence of a certain

abnormality in a 3D scan than a 2D one and there is the possibility of increasing

psychological bonding between the parents and the baby. A large volume ofliterature and documentation is expected to come out in the coming years and the

diagnosis of congenital anomalies could receive revived attention. Presentevidence has already suggested that even small defectssuch as spina bifida, cleftlips/palate, and polydactyl may be more lucidly demonstrated. Other more subtle

features such as low-set ears, facial dysmorphia orclubbing of feet can be betterassessed, leading to more effective diagnosis of chromosomal abnormalities. The

study of fetal cardiac malformations is also receiving attention. The ability to

obtain a good 3D picture is nevertheless still very much dependent on operator

skill, the amount of liquor around the fetus, it's position and the degree ofmaternal obesity, so that a good image is not always readily obtainable. Other

experts in this field have not considered that 3D ultrasound will be a mandatory

evolution of our conventional 2D scans; rather it is an additional piece of tool like

Doppler ultrasound. Whether 3D ultrasound will provide unique information ormerely supplemental information willremain to be seen. It's greatest potential is

still in research and particularly in the study offetal embryology.

About Safety: It has been over 35 years since ultrasound was first used onpregnant women. Unlike X-rays, ionizing irradiation is not present and embryo

toxic effects associated with such irradiation should not be relevant. The use of

high intensity ultrasound is associated with the effects of "cavitations" and"heating" which can be present with prolonged insonation in laboratorysituations. Harmful effects in cells of experimental animals or humans however

have not been demonstrated in the large amount ofstudies that have so farappeared in the medical literature purporting to the use of diagnostic ultrasound in

the clinical setting. Apparent ill-effects such as low birth weight, speech and

hearing problems, and non-right-handedness reported in small studies have not

been confirmed or substantiated in larger studies from Europe. The complexitiesof some of the studies have made the observations difficult to interpret.

Nevertheless continual vigilance is necessary particularly in areas of concern such

as the use of pulsed Doppler in the first trimester.

The greatest risks arising from the use of ultrasound are the possible over- and under- diagnosis

brought about by inadequately trained staff, often working in relative

isolation and using poor equipment.

BY VIII STD. FROM T.V. NAGAR HIGH SCHOOL, AMBATTUR,

CHENNAI 53

Amerthavalli, R. Mageswari , G. Sudha

A. Ranjani M. Nithya
http://news2.thdo.bbc.co.uk/hi/english/sci/tech/newsid_98000/98151.stmhttp://www.ob-ultrasound.net/voluson.html#betterhttp://www.telegraph.co.uk/et?ac=001662020400265&rtmo=LiG7xlLd&atmo=99999999&pg=/et/98/11/2/nscan02.htmlhttp://3dultrasound.ucsd.edu/recentpapers.htmlhttp://3dultrasound.ucsd.edu/recentpapers.htmlhttp://3dultrasound.ucsd.edu/recentpapers.htmlhttp://www.ob-ultrasound.net/images/cleftlip.jpghttp://www.ob-ultrasound.net/images/cleftlip.jpghttp://www.ob-ultrasound.net/images/polydcty.jpghttp://www.ob-ultrasound.net/images/clubfoot.jpghttp://3dultrasound.ucsd.edu/papers/mainz/heart_mainz.pdfhttp://health.excite.com/content/article/1728.55256http://health.excite.com/content/article/1728.55256http://news2.thdo.bbc.co.uk/hi/english/health/newsid_189000/189482.stmhttp://news2.thdo.bbc.co.uk/hi/english/health/newsid_189000/189482.stmhttp://www.ob-ultrasound.net/cavitat.htmhttp://www.ob-ultrasound.net/heating.htmhttp://www.aium.org/stmts.htm#In%20Vitro%20Biological%20Effectshttp://www.aium.org/stmts.htm#In%20Vitro%20Biological%20Effectshttp://www.ob-ultrasound.net/joewoo3x.htmlhttp://www.ob-ultrasound.net/joewoo3x.htmlhttp://news2.thdo.bbc.co.uk/hi/english/sci/tech/newsid_98000/98151.stmhttp://www.ob-ultrasound.net/voluson.html#betterhttp://www.telegraph.co.uk/et?ac=001662020400265&rtmo=LiG7xlLd&atmo=99999999&pg=/et/98/11/2/nscan02.htmlhttp://3dultrasound.ucsd.edu/recentpapers.htmlhttp://3dultrasound.ucsd.edu/recentpapers.htmlhttp://www.ob-ultrasound.net/images/cleftlip.jpghttp://www.ob-ultrasound.net/images/cleftlip.jpghttp://www.ob-ultrasound.net/images/polydcty.jpghttp://www.ob-ultrasound.net/images/clubfoot.jpghttp://3dultrasound.ucsd.edu/papers/mainz/heart_mainz.pdfhttp://health.excite.com/content/article/1728.55256http://news2.thdo.bbc.co.uk/hi/english/health/newsid_189000/189482.stmhttp://www.ob-ultrasound.net/cavitat.htmhttp://www.ob-ultrasound.net/heating.htmhttp://www.aium.org/stmts.htm#In%20Vitro%20Biological%20Effectshttp://www.aium.org/stmts.htm#In%20Vitro%20Biological%20Effectshttp://www.ob-ultrasound.net/joewoo3x.html


7/7

optsub majinven att ultrasound

Documents