-- Beverly L. Beech,
1999 Midwifery Today #51 (Please read this overview article.)
“It should not be forgotten, however, that
numerous studies on rats, mice and monkeys over the years have found reduced foetal
weight in babies that had ultrasound in the womb compared with controls. Nor
should it be forgotten that in the monkey studies (Tarantal et al., 1993) the
ultrasound babies sat or lay around the bottom of the cage, whereas the little
control monkeys were up to the usual monkey tricks. Long-term follow up of the
monkeys has not been reported. Do they reproduce as successfully as the
controls? And, as Jean Robinson has noted: "Monkeys do not learn to read,
write, multiply, sing opera, or play the violin." Human children do, and
perhaps we should consider seriously whether the huge increases in children
with dyslexia and learning difficulties are a direct result of ultrasound
exposure in the womb.”
“Furthermore, when a woman
is scanned her baby’s ovaries are also scanned. So if the woman had seven scans
during her pregnancy, when her pregnant daughter eventually presents years
later at the antenatal clinic, her developing baby will already have had seven
scans. Do women really know what they consent to when they rush to hospital to
have their first ultrasound scan, then trustingly agree to further scans?”
Comment: Low systemic amounts of vitamin C (ascorbic acid, AA) predispose one to
bruising; a gentle bump causes injury; high AA protects against bruises; high
amounts accelerate healing from injuries.
Related harms: Animal studies show experimental use of
ultrasound to perforate the membrane of the blood brain barrier, predisposing
to future meningitis and neural inflammation by infections. The experimenters’
claim the effect is transitory, but this is questionable.
Long Term Susceptibility: It is hard to show foetal ultrasound
exposure predisposes to later vaccine-related neural inflammation and
susceptibility to meningitis, but this is a credible possibility. Neural development
retardation and other cognitive abnormalities have been shown to be related
effects of foetal ultrasound.
Beware: Ultrasound, Scurvy and Vaccination together
are factors producing increased harmful effects.
Countermeasures: Take or eat at least several grams of AA per
day and >10 grams per day the week of the ultrasound. Eliminate all unneeded
(medically unnecessary) ultrasounds.
Lower ultrasound intensity-levels and durations where possible.
Conclusion: Combine borderline scurvy (low vitamin C and
ultrasound; the injury is greater and the healing is negligible. Scurvy magnifies ultrasound injury by a
factor proportional to the amount of malnutrition. There is no AA measurement
or vitamin C supplementation in ultrasound protocols.
Whatever happened to “do no harm”? Do not believe ultrasound is safe.
The application of ultrasound is big
business; in some cases the charges for ultrasound are nearly the same as for
all other prenatal treatment. Ultrasound provides intra uterine visibility that
may be desired, if promoted, by both doctors and patients. It is popular both
with patients and doctors and it is very
profitable for
practitioners and provider organizations.
Its safety to the baby is highly
suspect; ultrasound use has lead to developmental retardation in foetus and
postpartum of monkeys. The supporting, Tarantal
et al 1993, study is by a serious researcher and is well cited by many other
concerned authors, but it is not found online.
There exist economic motivations to
keep our scientific consensus oblivious of ultrasound’s multiple harms. Research funds have been allocated
towards increasing
the marketability of the machines. To great financial success.
One company sold $275 millions worth
of machines in one year. (2010) There are conflicts-of-interest (practitioner
profits) in providing more and more unnecessary ultrasound procedures. The
autism epidemiological statistics have changed from ~1/4000 to ~1/100. The
societal and insurance costs of mental disabilities are huge: Medical, medical insurance,
permanent disabilities, family expenses, social security, special training,
lost productivity, lost income, lost taxes.
Public funds for studies of
ultrasound safety or dangers have been withheld/blocked/under-funded with
little safety improvements for more than 40 years, despite the increasing
dangers. Still under funded and unable to prove the obvious, despite the
increased power levels of the newer ultrasound machines. Where are the follow
up experiments to the Tarantal study made in 1993?
The result is that more iatrogenic
disabilities are produced at ever increasing ultrasound power levels. Part of the autism epidemic is likely
to be due to ultrasound cellular destruction/disruption, aggravated by low AA
systemic levels.
In my own case, a single ultrasound tooth cleaning resulted
in deep tooth pain for a period of 3 months, accompanied by a progressive slow
loss of the sense of balance, which continues to slowly worsen.
For the therapeutic benefits vs.
harms physical mechanisms summary and overview see Dr. John Srbely: http://www.sonicrelief.com/learn/whitepaper.pdf
Cell disruption/destruction can be
therapeutic. http://www.foxnews.com/health/2012/04/17/ultrasound-beam-can-destroy-prostate-cancer-without-side-effects-study-finds/
Outcomes are better than other
treatments like radiation or surgery.
Some of the first midwife-concerned
studies of adverse foetal ultrasound affects are dated around 1990-1992.
Ultrasound machines are now more than 5-50 times more powerful today, 23 years
later. People trained in using
these machines have poor level of understanding of the energies that they apply
and the physics of how they do harm.
Everyone assumes they are safe, without proof, and proofs of the intrinsic
unsafenesses, where known, are not taught. Everyone seems oblivious of the
dangers.
Propaganda based on cited-articles’
selection and selective omissions to support an agenda or make false appear
true are found on the web pretending to be “science based”. Selective omissions
obscure the underlying proven physics, chemistry, and cellular mechanisms and
the basic scientific studies of harms actually produced. Science is being ignored
by people who claim to represent science, as will be shown below.
Good faith studies where critical
variables are not controlled or are unknown are also not valid science. Citing
such defective articles in meta-studies is also not scientific; it may be good
advertising. But to claim a sponsored, selection biased, flawed meta-study to
be “science based” is fraud.
Cellular, animal, and human
ultrasound damage studies have shown various permanent and sometimes
cell-killing, gene scrambling injury to membranes, to tissues, to teeth, to
DNA, to mitochondrial and organelle bodies. Ultrasound causes disruptions with
subtle, permanent or slow-to-heal nervous system malfunctions causing
disabilities. Genetic damage has been proven. Multi generation effects of
ultrasound cellular disruptions are not well enough studied. Health regulators
are not connecting the links between known dangers and clinical practices. Safety margins are not well understood
or enforced. Doctors, patients and
regulators are oblivious. Our
genetic pool in countries that practice modern medicine is in danger.
Fully characterizing the conditions
and the details of the harms requires a research team including physicists, chemists,
biochemists, cellular-microbiologists, electron microscopists, biologists,
medical pathologists, all of the highest degree of skill and competence. Such teams are highly expensive to
maintain and have many competing tasks of interest. It does not help that when a relevant study is done and
published that it is in an obscure scientific journal that is not monitored by
public health administrators.
Much of what has been learned about
the harms from ultrasound when applied to various living forms remains unknown
to the popular medical consensus.
Except to the parents and to the practical medical professions, such as
midwifery and nursing, who see the tragic results. The midwives have expressed their concerns and have been
largely ignored by the better-funded medical research establishment whose
practitioners have classified the harms as “unproven” and the dangers as
“unknown” in meta-studies and “science based” propaganda articles. Regulators, notorious for job switching
between government and industry, have failed to ask for or to provide adequate
funds for ultrasound safety research.
Ultrasound energy is physical motion
(high frequency vibration) with measurable physical attributes of
intensity/amplitude, with vibration-frequencies above audible and having
various waveform (pulse) envelope shapes.
Sound energy waves can be reflected, concentrated, and can be focused or
diffuse. Sound waves can bounce off of bone structures and form amplified
standing waves of higher intensity, much higher than safe levels in areas of
focus. Tissue/air and tissue/liquid boundaries are locations for cavitation.
Ultrasound can and frequently does
cause cavitation, which produces micro sized bubbles that collapse into
pinpoint centers of super high pressure and temperature. The high temperatures
cook cells’ micro components, DNA, RNA, bioactive molecules, hormones, enzymes,
organelles, and mitochondria.
From the physics, it is clear that
ultrasounds’ disruptive harm is proportional to intensity and duration. [Incident-energy] multiplied by
[Exposure-time]. Disruptive effects also depend on other sound-attribute
relationships: frequency, waveform shapes, standing wave amplification,
reflective-structure sound-wave focusing, and tissue/air/liquid boundary
concentration or cavitation effects.
Energy, when applied to cells and
tissues has many proven transformative bad (and some gentle and good) effects
on life in the form of cells, tissues, biofilms, and organic and cellular
systems. Forms of energy include: Electro-Magnetic radiation [intensity,
frequency (audio-radio), waveforms]; Heat/cold (IR); Ultraviolet; Lasers;
Diathermy. Forms of physical
motion energy include: Exercise; Massage; Chiropractic manipulation;
Sound/ultrasound [frequency, amplitudes, waveforms], etc. Ultrasound has been used to provide
visibility and in other studies calcification disruption/break-up and
blood-brain membrane cell-disrupting destruction.
In a nano scale, ultrasound
destroys/modifies parts of the body’s cells and organelles in a persistent way.
Regeneration/replacement of damaged tissue and nerve cells is needed and may be
defective as occurs for trauma and burn recovery. Too little attention is given
to vitamin nutrition in promoting recovery from ultrasound treatment injuries,
which are subtle and remain unnoticed and denied by practitioners.
Recent PMID Ultrasound research is
targeted to traumatic disrupting of the blood brain barrier in order to enable
passage of otherwise blocked medical agents. One study shows marked tissue
damage. Proof of microscopic tissue and cellular harm in rabbit experiments.
Rapid recovery is postulated as a hypothetical goal but complete recovery from
trauma is not proved. Degree of damage is hard to quantify without biopsy. Many
other studies have shown traces of permanent neural-system developmental
retardation and regressive functional impairment along with disruptive damage.
NLM recent papers indicate they are using the disruption
creatively with disregard for the long term permanent and delayed effects.
Evidence of ultrasound caused tissue damage was found in one paper. No follow-up on long term harms that
show up later. Disruption of BBB allows drugs into the brain and also makes
brain more vulnerable to infection, perhaps permanently more susceptible to
meningitis.
It is unlikely that the systemic
ideological blindnesses of the medical consensus over the last 200 years are
likely to change in the next 50 years. This is clear in the case of systematic
ignorance of vitamin C’s therapeutic dosage and its pharmacodynamic actions.
See Ely “Unprofitable Modalities” and “Denial of Infectious Theory of
Diseases”. Ely Dr
John Ely’s well-reasoned papers are too gentle on those who claim to be
scientists, but ignore science and who profit while doing harm to the public.
Ultrasound can be harmful; the money
is in promoting its widespread profitable use; not in increasing its safe use.
Improvement in safety depends on funding. The funding-gatekeepers depend on the
medical support industry. Documenting a complex and “unproven” safety issue is
always a low priority. Creating disabilities harms the patients, increases
medical insurance costs, but is good for the practitioner business. The medical consensus has a
profit-based conflict-of-interest that promotes oblivious denial of the reality
of harmful practices. Add overcharging and multiple-counting of costs hidden in
the billing or overhead costs and you have some of the bases of our medical
system corruption’s runaway costs.
After doing all the bottom-up
research I found that a game is being played with the public. A Google top-down search [Ultrasound
Dangers] brought up a first entry from a site http://www.sciencebasedmedicine.org/ that was at variance with all the material
I found citing the underlying real science of the dangers.
This website is obviously a
propaganda site used to display articles specially written to pretend that Science
is supporting safety and other practices, where dangers can be written about and
minimized. They selectively categorize medical studies showing harmful results
of ultrasound as not credible. This is not truthful.
So it is not just a bunch of
confused ignorant scientists that should know better. Here is an organization
that publishes propaganda supplied by their supporters, which have socially
harmful ideological, financial and business interests. This would be fine if
the public was not being harmed by their practices. But this is not the case.
Some of their profits are dirty.
One can conclude that “science based
medicine” is a fraud. Just like
the pseudo-science of global warming that was shown to lead to taxes flowing to
undeserving profiteers. I have found other evidences of stacking-the-deck with
articles that are pushed to the top of the search results. This is just one of
the most obvious.
“Science Based Medicine” articles
need to be examined critically for validity. All of them may be planted to produce a plausible
justification for practices that either rip off the medical consumer or are
actually harmful.
Caveat Emptor! Beware meta-study
selection bias and “Science-based” propaganda. They are well financed by the
medical profit making providers.
Examine the contrasting studies of
researchers that are not cited to get the full picture. WWW.Whale.to
is a good place to start.
Our medical system’s politicians need to be replaced by midwives who
will approve research justifying comprehensive ultrasound safety testing. When
proven dangerous, ultrasound machines need to be made safe or made illegal for
human medical use. Legal recourse to compensation in cases of harm needs to be
enabled. Where ultrasound was used and it did harm, the government, the propagandists
and the manufacturers jointly should be liable. It may be easy to prove Rico
Act Conspiracy.
But first, stop doing all the unnecessary ultrasounds, as the AMA has
requested.
1.
http://www.midwiferytoday.com/articles/ultrasound.asp
Ultrasound: Weighing the Propaganda Against the Facts, By Beverly L. Beech,
1999, Midwifery Today
2.
http://www.whale.to/a/questions9.html
Questions about Prenatal Ultrasound and the Alarming Increase in Autism, By
Caroline Rodgers 2006 Midwifery
Today
3.
http://www.sonicrelief.com/learn/whitepaper.pdf Dr John Srbely, Bio-physical Effects
4.
http://www.whale.to/a/ultrasound_unsound.html
Included below with updates.
5.
http://www.greenmedinfo.com/anti-therapeutic-action/obstetric-ultrasonography
6.
http://web.archive.org/web/20020205080758/http://gentle-birth.com/ultrasound.htm
7.
http://www.whale.to/w/autism.html
Good Overview Page.
8.
http://www.whale.to/a/when1.html
9.
http://www.whale.to/a/ultrasound1.html
10.
http://web.archive.org/web/20040211043958
1.
http://articles.mercola.com/sites/articles/archive/2008/01/02/ultrasound-may-harm-unborn.aspx
2.
http://articles.mercola.com/sites/articles/archive/2006/08/22/for-the-health-of-your-baby-stay-away-from-unnecessary-ultrasounds.aspx
© Copyright KF and KM Poehlmann, January 2013, all rights reserved.
(Katherine
Poehlmann, PhD and Karl Poehlmann)
Inflammation, chronic infections, nutrition and immunity are topics we have researched broadly in our studies of worldwide medical knowledge, documented on the Internet and in the historical archives of medicine. We have spent over ten calendar years reading about these inter-related subjects, attending postgraduate medical conferences. We have read countless medical texts, abstracts, and papers, online in the National Library of Medicine and contained at various authoritative medical, nutritional and biological websites. The mass of the available information worldwide is tremendous. Search engines can reach much of it, so it can be correlated productively.
Nothing herein or referenced herein should be considered prescriptive for any medical condition. This information is for study and education purposes only. The readers are advised to find and consult well-educated, trained and licensed medical and nutritional practitioners who shall evaluate the many circumstances and conditions of each of their patients and will devise appropriate treatments and nutritional plans for them. It is recognized that each person has the right and duty to be well informed about the best foods, nutrition and medical practices available that will promote their own good health. The opinions expressed herein are those of the author(s) and the sources cited and there are many divergences of opinions on many topics. The readers must resolve the conflicts, in their own minds, after careful consideration of all the details and after any further necessary research and study.
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www.sciencebasedmedicine.org/.../are-prenatal-ultrasounds-da...
Aug 30, 2011 – Several
questionable sources are spreading alarms about the possible dangers of prenatal ultrasound exams
(sonograms). An example is ...
www.greenhealthwatch.com/newsstories/.../ultrasound-hurt.ht...
Ultrasound, ultrasound pictures, dangers 3d
ultrasound fetus, 3d ultrasound dangers to
fetal, fetal ultrasound dangers - Ultrasound -
just looking can hurt!- Green ...
www.naturalnews.com/028853_ultrasound_fetus.htmlShare
www.everyday-wisdom.com/dangers-of-ultrasound.html
Knowing the threats and potential dangers of ultrasound may help you stay well
and healthy. The potential threats are....
www.webmd.com/baby/.../prenatal-portraits-darling-dangerou...
Prenatal Portraits: Darling or Dangerous? Many businesses offer ultrasound pictures
and videos of unborn babies for entertainment purposes, but some experts ...
www.midwiferytoday.com/articles/ultrasoundrodgers.asp
by C Rodgers - Related
articles
A far simpler possibility worthy of investigation is the
pervasive use of prenatal ultrasound, which can
cause potentially dangerous thermal effects.
www.unhinderedliving.com/pultra.html
NO STUDIES have been done which prove the
safety of these devices, and the American Medical Association recommends
AGAINST unnecessary exposure.
ask.metafilter.com/.../So-really-how-dangerous-are-ultrasound...
19 answers - Sep 9, 2009
http://www.ncbi.nlm.nih.gov/pubmed/19291813.
This study is a meta-analysis which means that it summarizes the different
epidemiological studies ...
voices.yahoo.com/the-dangers-ultrasounds-178087.html
Jan 30, 2007 – The
american Medical Association has warned of the possible dangers of prenatal ultrasounds and has
advised that medical professionals ...
The following pages contain notes on
ultrasound safety factors documented on the web. The information is both compelling and disturbing. Changes have been made to recover
broken link articles cited by reference to the web.archive website aka Web
Wayback Machine. http://www.whale.to/a/ultrasound_unsound.html
[Updated here to fix broken links
to dead websites using web.archive.org = Web “Wayback Machine”]
Here is a link to an interesting article entitled Ultrasound - Weighing the
propaganda against the facts. It was written by the
author of Ultrasound Unsound?
http://web.archive.org/web/20040211043958/http://www.aims.org.uk/ultrasound.htm
I have seen other studies identifying negative side effects of
ultrasounds. One in particular found that as little as 1 ultrasound could
delay a child's speech by as much as 9 months. This study was done in
Canada, not the US. Other findings have suggested that the increase in
left-handedness among children who were scanned before birth is linked to the
ultrasound, which would show that the scan does alter the brain in some
way.
In the US, keep in mind that medical equipment does not undergo the type of
testing that a drug must go through to get on the market. The scans used
today are more invasive than the earlier ones, so it will take a few more
decades to really know the outcome. The recent generations of children
who have been scanned are in fact the guinea pigs that will decide the safety
of ultrasounds -- which have done nothing to lower childbirth death rates, but
have sent the C-section rate dangerously high in the US.
The article above points out that the doppler, used to detect heart tones on
every prenatal visit unless you have a midwife who uses a fetalscope), may
cause even more damage than the ultrasound.
-Susan
*******
This is straight from the journal "Epidemiology" (Dec 2001), and
suggests that ultrasound is associated with mild brain damage.
http://web.archive.org/web/20020803214823/http://www.mercola.com/2001/dec/19/ultrasound.htm
My boss, Dr. Mark Ellisman, is a world-renowned research
scientist at UCSD who specializes in imaging technologies for the study of
brain structure at the cellular level; he has personally found evidence of
something called "cavitation", which is the "rapid formation and
collapse of vapor pockets" in fluid within tissue. When my wife and I
became pregnant he warned me to keep the ultrasound as short as possible. He knows
what he's talking about.
Here's a relevant quote:
"Free radical production in amniotic fluid and blood plasma
by medical ultrasound, probably following gaseous cavitation, has been detected
by Crum et al (1987). This provides a likely mechanism for the origin of the
DNA damage. Because of these confirmations and a report by Ellisman et al
(1987) that diagnostic levels of ultrasound may disrupt myelination in neonatal rats, the need
for regulation, guidance, and properly controlled clinical studies is
clear." http://www.aimsusa.org/ultrasnd.htm
Here's another useful link: http://www.alternamoms.com/ultrasound.html
So please don't consider this a benign procedure or an opportunity to get some pretty pictures. and
*please* don't get an extra 3D ultrasound, which is a very long scan, to get
the 3D picture of your baby. There is a real risk, and it's just not worth it.
Do a Google search on "+ultrasound +cavitation" or "+ultrasound
+Ellisman" and convince yourself.
Just my .02 Dave
*******
http://web.archive.org/web/20020804150336/http://www.mothering.com/11-0-0/html/11-2-0/ultrasound-risk.shtml
Weighing the Risks: What You Should Know about Ultrasound
By Sarah Buckley
Issue 102, September/October 2000
Ultrasonography was originally developed during World War II to detect enemy
submarines. Its use in medicine was pioneered in Glasgow, Scotland, by Dr. Ian Donald, who first used
ultrasound to look at abdominal tumors, and later babies in utero in the
mid-1950s.1 The use of ultrasound in
pregnancy spread quickly.
In westernized healthcare systems, ultrasound, which may be offered to a
pregnant woman either to investigate a possible problem at any stage of pregnancy or as a routine scan at
around 18 weeks, has become almost universal in pregnancy. In Australia, where
I live, 99 percent of pregnant
women have at least one scan, paid for in part by our federal
government, through Medicare. In
fact, from 1997 to 1998 Medicare paid out AU$39 million for obstetric scans,
compared to AU$54 million for all other obstetric Medicare costs. In the US,
the American College of Obstetrics and Gynecology (ACOG) estimates that 60 to
70 percent of pregnant women are
scanned, despite an official statement from ACOG that recommends against
routine ultrasound.2 At a cost of roughly $300 per procedure, this represents a
cost of approximately $70 to $80 million each year in the US.
Besides routine scans, ultrasound can be prescribed to investigate problems
such as bleeding in early pregnancy. Later in pregnancy, ultrasound can be used
when a baby is not growing, or when breech or twin births are suspected. In
such cases, the information gained from ultrasound can be very useful in
decision-making, and generally most professionals support the use of ultrasound
in this context.
It is such use of routine prenatal ultrasound (RPU) that is more controversial,
as this practice involves scanning all pregnant women in the hope of improving
the outcome for some mothers and babies. RPU seeks to gain four main types of
information:
Estimated due date.
Dating a pregnancy is most accurate at early stages, when babies vary the
least in size. By contrast, at 18 to 20 weeks the expected date of delivery is
only accurate to within a week either way. Some studies have suggested, however, that an early examination
or a woman's own estimation of her due date can be as accurate as RPU.3,4
Unsuspected physical abnormalities. While many women are reassured by a normal
scan, in fact RPU detects only between 17 percent and 85 percent of the one in
50 babies that have major abnormalities at birth.5,6 A recent study
from Brisbane, Australia, showed that ultrasound at a major women's hospital
missed about 40 percent of abnormalities, many of which are difficult or
impossible to detect.7 The major causes of intellectual disability,
such as cerebral palsy and Down syndrome, or heart and kidney abnormalities,
are unlikely to be picked up on a routine scan.
There is also a small chance that the diagnosis of an abnormality is false
positive. In some instances, normal babies have been aborted because of
false-positive diagnoses.8 A United Kingdom survey found that one in
200 babies aborted for major abnormalities were wrongly diagnosed.9
In addition to false positives, there are also uncertain cases in which the
ultrasound image cannot be easily interpreted, and the outcome for the baby is
not known. In one study involving babies at higher risk of abnormalities,
almost 10 percent of scans were uncertain.10 This can create immense
anxiety for the woman and her family that may not be allayed by the birth of a
normal baby: in the same study, mothers with questionable diagnoses still had
associated anxiety three months after the child's birth. Uncertain findings
also lead to repeated and/or prolonged scans, increasing the expense,
inconvenience, and dosage of ultrasound.
In some cases of uncertainty, further tests such as amniocentesis are
recommended. In such situations, there may be up to two weeks wait for results,
during which time a mother must consider whether or not she will terminate the
pregnancy if an abnormality is found. Even mothers who receive reassuring news
have felt that this process has interfered with their relationship with their
babies.11
Location of the placenta.
A very
low-lying placenta (placenta previa) puts mother and baby at risk of severe
bleeding, and usually necessitates a cesarean section. However, 19 out of 20
women who have placenta previa detected on RPU will be needlessly worried, as
the placenta will effectively move upwards as the pregnancy progresses.12
Furthermore,
detection of placenta previa by RPU has not been found to be safer than
detection in labor.13
Multiple fetuses. Ultrasound can detect the presence of more than one baby at
an early stage of pregnancy, but this knowledge affords no documented health
advantages for mother or babies, and, without RPU, almost all multiple
pregnancies are discovered before birth.14
Why Are RPUs So Popular?
Supporters of RPU argue that availability of ultrasonic information leads to
better outcomes for mother and baby. While this seems logical, researchers have
not found evidence of significant benefit from RPU, and the issue of the safety
of ultrasound has not yet been resolved.
From a research perspective, the most significant benefit of RPU is a small
reduction in perinatal mortality, that is the number of babies dying around the
time of birth. This is, however, merely a statistical reduction since perinatal
mortality rates do not include deaths that occur before five to six months'
gestation. Often when a baby is found to have a fatal
abnormality on RPU, the pregnancy is terminated before this time, excluding the
baby from perinatal statistics.
RPU proponents presume that early diagnosis and termination is beneficial to
women and their families. However, the discovery of a major abnormality on RPU
can lead to very difficult decision-making. Some women who agree to
have an ultrasound are unaware that they may get information about their baby
that they do not want, as they would not contemplate a termination. Other women
can feel pressured to have a termination, or at least feel some emotional
distancing from their "abnormal" baby.15
Furthermore, there is no evidence that women who have chosen termination are,
in the long term, psychologically better off than women whose babies have died
at birth. In fact, there are suggestions that the reverse may be true in some
cases.16 In choosing a possible stillbirth over a termination, women
at least get social acknowledgment and support, and are able to
grieve openly. Where termination has been chosen, women are unlikely to share
their story with others and can experience considerable guilt and pain from the
knowledge that they themselves chose the loss.17
Another purported benefit of RPU is a reduced risk of being induced for being
"overdue," because RPU dating gives a more certain estimated due
date. However, there is no clear evidence that this is true, as the possibility
of induction is more determined by hospital or doctor policy than by the
availability of RPU.19
Many supporters of RPU claim that it's a pleasurable experience, and
contributes to bonding between mother (and father, if he is present) and baby.
While it is true that it can be exciting to get a first glimpse of one's baby
in utero, there is no evidence that it helps attachment or encourages healthier
behavior toward the baby.20 For most women, bonding occurs naturally
when they begin to feel fetal movements at 16 to 20 weeks.
Reasons for Concern
Ultrasound waves are known to affect living tissues in at least two ways.
First, the sonar beam heats the highlighted area by about 1°C (2°F). This is
presumed to be insignificant, based on whole-body heating in pregnancy, which
seems to be safe up to 2.5°C (5°F).21 The second effect is
cavitation, where the small pockets of gas that exist within mammalian tissue
vibrate and then collapse. In this situation "...temperatures of many
thousands of degrees Celsius in the gas create a wide range of chemical products,
some of which are potentially toxic."22 The significance of
cavitation in human tissue is unknown.
A number of studies have suggested that these effects are of real concern in
living tissues. The first study indicating problems analyzed cells grown in the
lab. Cell abnormalities caused by exposure to ultrasound were seen to persist
for several generations.23 Another study showed that, in newborn
rats (who are at a similar stage of brain development as humans at four to five
months in utero), ultrasound can damage the myelin that covers nerves,24
indicating that the nervous system may be particularly susceptible to damage
from this technology. In 1999, an animal study by Brennan and colleagues,
reported in New Scientist,25 showed that exposing mice to dosages
typical of obstetric ultrasound caused a 22 percent reduction in the rate of
cell division, and a doubling of the rate of cell death in the cells of the
small intestine.
Studies on humans exposed to ultrasound have shown possible adverse effects,
including premature ovulation,26 preterm labor or miscarriage,27,
28 low birthweight,29 poorer condition at birth,30, 31
dyslexia,32 delayed speech development,33 and less
right-handedness,34, 35 a factor which in some circumstances can be
a marker of damage to the developing brain. In addition, one Australian study
showed that babies exposed to five or more ultrasounds were 30 percent more
likely to develop intrauterine growth retardation (IUGR)--a condition that
ultrasound is often used to detect.36
Two long-term randomized controlled trials, comparing exposed and unexposed
children's development at eight to nine years of age, found no measurable
effect from ultrasound.37, 38 However, as the authors note,
intensities used today are many times higher than in 1979 to 1981. A later
report of one of these trials39 indicated that scanning time was
only three minutes. More studies are obviously needed in this area,
particularly in Doppler ultrasound, where exposure levels are much higher, and
in vaginal ultrasound, where there is less tissue shielding the baby from the
transducer.
A further problem with studying ultrasound's effect is the huge range of
output, or dose, possible from a single machine. Modern machines can give
comparable ultrasound pictures using either a lower or a 5,000 times higher
dose,40 and there are no standards to ensure that the lowest dose is
used. Because of the complexity of machines, it is difficult to even quantify
the dose given in each examination.41 In the US, as in Australia, training
is voluntary (even for obstetricians), and the skill and experience of
operators varies widely.
In all the research done on ultrasound, there has been very little interest in
women's opinions of RPU, and the consequences of universal scanning for women's
experience of pregnancy. In her thoughtful book on prenatal diagnosis, The
Tentative Pregnancy,42 Barbara Katz Rothman suggests that the large numbers of
screening tests currently being offered to check for abnormalities makes every
pregnancy tentative until reassuring results come back.
Ultrasound is not compulsory, and I suggest that each woman consider the risks,
benefits, and implications of scanning for her own particular situation. If you
decide to have a scan, be clear about the information that you do and do not
want to be told. Have your scan done by an operator with a high level of skill
and experience (usually this means performing at least 750 scans per year) and
say that you want the shortest scan possible. If an abnormality is found, ask
for counseling and a second opinion as soon as practical. And remember, it's
your baby and your choice.
Notes
1. Ann Oakley, "The History of Ultrasonography in Obstetrics," Birth
13, no. 1 (1986): 8-13.
2. American College of Obstetricians and Gynecologists, "Routine
Ultrasound in Low-Risk Pregnancy, ACOG Practice Patterns: Evidence-Based Guidelines for Clinical
Issues," Obstetrics and Gynecology 5 (August 1997).
3. O. Olsen et al., "Routine Ultrasound Dating Has Not Been Shown to Be
More Accurate Than the Calendar Method," Br J Obstet Gynaecol 104, no. 11
(1997): 1221-1222.
4. H. Kieler, O. Axelsson, S. Nilsson, and U. Waldenstrom, "Comparison of
Ultrasonic Measurement of Biparietal Diameter and Last Menstrual Period as a
Predictor of Day of Delivery in Women with Regular 28-Day Cycles,"
Acta-Obstet-Gynecol-Scand 75, no. 5 (1993): 347-349.
5. B. G. Ewigman, J. P. Crane, F. D. Frigoletto et al., "Effect of
Prenatal Ultrasound Screening on Perinatal Outcome," N Engl J Med 329, no.
12 (1993): 821-827.
6. C. A. Luck, "Value of Routine Ultrasound Scanning at 19 Weeks: A Four
Year Study of 8849 Deliveries," British Medical Journal 34, no. 6840
(1992): 1474-1478.
7. F. Y. Chan, "Limitations of Ultrasound," paper presented at
Perinatal Society of Australia and New Zealand 1st Annual Congress, Freemantle,
1997.
8. AIMS UK, "Ultrasound Unsound?," AIMS UK Journal 5, no. 1 (Spring
1993).
9. I. R. Brand, P. Kaminopetros, M. Cave et al., "Specificity of Antenatal
Ultrasound in the Yorkshire Region: A Prospective Study of 2261 Ultrasound
Detected Anomalies," Br J Obstet Gynaecal 101, no. 5 (1994): 392-397.
10. J. W. Sparling, J. W. Seeds, and D. C. Farran, "The Relationship of
Obstetric Ultrasound to Parent and Infant Behavior," Obstet Gynecol 72, no.
6 (1988): 902-907.
11. A. Brookes, "Women's Experience of Routine Prenatal Ultrasound,"
Healthsharing Women: The Newsletter of Healthsharing Women's Health Resource
Service (Melbourne, Australia) 5, no.s 3, 4 (December 1994-March 1995).
12. MIDIRS, Informed Choice for Professionals, Ultrasound Screening in the
First Half of Pregnancy: Is It Useful for Everyone? (UK: MIDIRS and the NHS
Centre for Reviews and Dissemination, 1996).
13. A. Saari-Kemppainen, O. Karjalainen, P. Ylostalo et al., "Ultrasound
Screening and Perinatal Mortality: Controlled Trial of Systematic One-stage
Screening in Pregnancy," The Lancet 336, no. 8712 (1990): 387-391.
14. See Note 12.
15. See Note 11.
16. D. Watkins, "An Alternative to Termination of Pregnancy," The
Practitioner 233, no. 1472 (1989): 990, 992.
17. See Note 12.
18. Ibid.
19. Ibid.
20. Ibid.
21. "American Institute of Ultrasound Medicine Bioeffects Report
1988," J Ultrasound Med 7 (September 1988): S1-S38.
22. Ibid.
23. D. Liebeskind, R. Bases, F. Elequin et al., "Diagnostic Ultrasound:
Effects on the DNA and Growth Patterns of Animal Cells," Radiology 131,
no. 1 (1979): 177-184.
24. M. H. Ellisman, D. E. Palmer, and M. P. Andre, "Diagnostic Levels of
Ultrasound May Disrupt Myelination," Experimental Neurology 98, no. 1
(1987): 78-92.
25. Brennan et al., "Shadow of Doubt," New Scientist 12 (June 1999):
23.
26. J. Testart, A. Thebalt, E. Souderis, and R. Frydman, "Premature
Ovulation after Ovarian Ultrasonography," Br J Obstet Gynaecol 89, no. 9
(1982): 694-700.
27. See Note 13.
28. R. P. Lorenz, C. H. Comstock, S. F. Bottoms, and S. R. Marx,
"Randomised Prospective Trial Comparing Ultrasonography and Pelvic
Examination for Preterm Labor Surveillance," Am J Obstet Gynecol 162, no.
6 (1990): 1603-1610.
29. J. Newnham, S. F. Evans, C. A. Michael et al., "Effects of Frequent
Ultrasound During Pregnancy: A Randomised Controlled Trial," The Lancet
342, no. 8876 (1993): 887-891.
30. S. B. Thacker, "The Case of Imaging Ultrasound in Obstetrics: A
Review," Br J Obstet Gynaecol 92, no. 5 (1985): 437-444.
31. J. P. Newnham et al., "Doppler Flow Velocity Wave Form Analysis in
High Risk Pregnancies: A Randomised Controlled Trial," Br J Obstet
Gynaecol 98, no. 10 (1991): 956-963.
32. C. R. Stark, M. Orleans, A. D. Havercamp et al., "Short and Long Term
Risks after Exposure to Diagnostic Ultrasound in Utero," Obstet Gynecol 63
(1984): 194-200.
33. J. D. Campbell et al., "Case-control Study of Prenatal Ultrasonography
in Children with Delayed Speech," Can Med Ass J 149, no. 10 (1993):
1435-1440.
34. K. A. Salvesen, L. J. Vatten, S. H. Eik-nes et al., "Routine
Ultrasonography in Utero and Subsequent Handedness and Neurological
Development," British Medical Journal 307, no. 6897 (1993) 159-164.
35. H. Kieler, O. Axelsson, B. Haguland et al., "Routine Ultrasound
Screening in Pregnancy and the Children's Subsequent Handedness," Early
Human Development 50, no. 2 (1998): 233-245.
36. See Note 31.
37. K. A. Salvesen, L. S. Bakketeig, S. H. Eik-nes et al., "Routine
Ultrasonography in Utero and School Performance at Age 8-9 Years," The
Lancet 339, no. 8785 (1992):85-89.
38. H. Kieler, G. Ahlsten, B. Haguland et al., "Routine Ultrasound
Screening in Pregnancy and the Children's Subsequent Neurological
Development," Obstet Gynecol 91, no. 5 (1998): 750-756.
39. See Note 37.
40. H. B. Meire, "The Safety of Diagnostic Ultrasound," Br J Obstet
Gynaecol 94 (1987): 1121-1122.
41. K. J. W. Taylor, "A Prudent Approach to Ultrasound Imaging of the Fetus
and Newborn," Birth 17, no. 4 (1990): 218-223.
42. Barbara Katz Rothman, The Tentative Pregnancy: How Amniocentesis Changes
the Experience of Motherhood (New York: W. W. Norton, 1993).
For more information on ultrasound, see the following articles in past issues
of Mothering: "Ultrasound: More Harm Than Good?" no. 77; "The
Trouble with Ultrasound," no. 57; "How Sound Is Ultrasound?" no.
34; "Ultrasound," no. 24; and "Diagnostic Ultrasound," no.
19.
Sarah Buckley (40) is a New Zealand-trained GP (family MD), and still in
training as partner to Nicholas. Mother of Emma (9), Zoe (6), and Jacob (4),
she is currently expecting her fourth baby and lives in Brisbane, Australia,
where she writes about pregnancy, birth, and parenting.
********
Shadow of a doubt
by Rob Edwards
ULTRASOUND SCANS
can stop cells from dividing and make them commit suicide.
A research team in Ireland say this is the first evidence that
routine scans, which have let doctors peek at fetuses and internal organs for
the past 40 years, affect the normal cell cycle.
A team led by Patrick Brennan of University College Dublin gave 12 mice an
8-megahertz scan lasting for 15 minutes. Hospital scans, which reflect
inaudible sound waves off soft tissue to produce images on a monitor, use frequencies
of between 3 and 10 megahertz and can last for up to an hour
The researchers detected two significant changes in the cells of the small
intestine in scanned mice compared to the mice that hadn't been scanned. Four
and a half hours after exposure, there was a 22 per cent reduction in the rate
of cell division, while the rate of programmed cell death or
"apoptosis" had approximately doubled.
Brennan believes there will be similar effects in humans. "It has been
assumed for a long time that ultrasound has no effect on cells," he says.
"We now have grounds to question that assumption."
Brennan stresses, however, that the implications for human health are
uncertain. "There are changes happening, but we couldn't say whether they
are harmful or harmless," he explains. The intestine is a very adaptable
organ that can compensate for alterations in the cell cycle, says Brennan.
It is possible that the sound waves damage the DNA in cells, delaying cell
division and repair. Brennan suggests that ultrasound might be switching on the
p53 gene which controls cell deaths. This gene, dubbed "the guardian of
the genome", produces a protein that helps cells recognise DNA damage and
then either self-destruct or stop dividing.
Studies in the early 1990s by researchers at the University of Rochester in New
York and the Batelle Pacific Northwest Laboratories in Richland, Washington,
showed that tissue heating due to ultrasound can cause bleeding in mouse
intestines. Ultrasonographers now tune the power of scans to reduce such
heating.
But Brennan's work is the first evidence that scans create changes in cells.
"Our results are preliminary and need further investigation," he
says. The team presented their results at the Radiology 1999 conference in
Birmingham last month and are now preparing them for submission to a
peer-reviewed journal.
Alex Elliott, a researcher in clinical physics at the University of Glasgow,
thinks that Brennan's results are important and should be followed with further
studies. "If the conditions of his experiments really compare to the
clinical use of ultrasound," he says, "we may have to review the
current safety limits."
>From New Scientist, 12 June 1999
*******
Here are some excerpts about ultrasound from "What Doctors Don't
Tell You"
by Lynne McTaggart. "No well controlled study
has yet proved that routine scanning of prenatal patients will improve the
outcome of pregnancy" - official statement from American College of
Obstetrics & Gynecology in 1984
Some studies show that, with ultrasound, you are more likely to lose your
baby. A study from Queen Charlotte's and Chelsea Hospital in London found
that women having doppler ultrasound were more likely to lose their babies than
those who received only standard neonatal care (17 deaths to 7).
A Norwegian study of 2,000 babies found that those subjected to routine
ultrasound scanning were 30% more likely to be left-handed than those who
weren't scanned. An Australian study demonstrates that frequent scans
increased the proportion of growth-restricted babies by a third, resulting in a
higher number of small babies. Exposure to ultrasound also caused
delayed speech, according to Canadian researcher Professor James Campbell.
The International Childbirth Education Association has maintained that
ultrasound is most likely to affect development (behavioral &
neurological), blood cells, the immune system, & a child's genetic makeup.
Besides the safety issue, there are considerable questions about accuracy.
There is a significant chance that your scan will indicate a problem when there
isn't one, or fail to pick up a problem actually there. One study found a
"high rate" of false positives, 17% of the pregnant women scanned
were shown to have small-for-dates babies, when only 6% actually did - an
error rate of nearly one out of three. Another study from Harvard showed
that among 3,100 scans, 18 babies were
erroneously labeled abnormal, and 17 fetuses with problems were missed.
Linda
********
this is from another list...
<<<According to Anne Frye, midwife and author of "Understanding
Lab Work in the Childbearing Year"
(4th Ed.)p. 405
Doppler Devices: Many women do not realize that Doppler fetoscopes are
ultrasound devices. (apparently, neither do many care providers. Time after
time, women are assured by doctors and even some nurse midwives that a Doppler
is not an ultrasound device.) . . . .
Not well publicized for obvious reasons, Doppler devices expose the fetus to
more powerful ultrasound than real time (imaging) ultrasound exams. One minute
of Doppler exposure is equal to 35 minutes of real time ultrasound. This is an
important point for women to consider when deciding between an ultrasound exam
and listening with a Doppler to determine viability in early pregnancy. . . . .
If you have a Doppler, put it aside and make a concerted effort to learn to
listen yourself! Save your Doppler for those rare occasions when you cannot
hear the heart rate late into pushing or to further investigate suspected fetal
death. " copyright l990, Anne Frye, B.H. Holistic Midwifery.
Personally, after 23 years of attending births, I would not permit a Doppler in
my house if I were pregnant. You always know that something is ultrasound
because there will be "jelly" involved. If you want a cheap listening
device for the baby's heart just save the core from a roll of toilet paper. Put
one end on the lower belly and the other on hubby's ear. If you want to know
your baby is doing well, count the fetal movements in a day. Starting at 9 a.m.
count each time the baby kicks. There should be l0 distinct movements by 3 p.m.
I think it's sad that some people will do anything to make a buck of the huge
pregnant market in North America. Please feel free to forward this post on to
any other lists.
Gloria Lemay, Vancouver BC
Wise Woman Way of Birth Courses
http://web.archive.org/web/20000902050959/http://www.birthlove.com/pages/wise_woman.html
>>>
********
http://web.archive.org/web/20070306212725/http://news.bbc.co.uk/1/hi/health/1751177.stm
This made me wonder what ultrasound does to developing babies if it can have such a drastic effect on a
testicle.
******
By Peggy O'Mara Issue 120, September/October 2003
“Is Ultrasound Safe? The National Institutes of Health cautions against routine use of ultrasound, noting that "the data on clinical efficacy and safety do not allow recommendation for routine screening at this time; there is a need for multidisciplinary randomized controlled clinical trials for an adequate assessment."7
“Similarly, the World Health Organization (WHO) urges prudence: "Ultrasound screening during pregnancy is now in widespread use without sufficient evaluation. Research has demonstrated its efficacy for certain complications of pregnancy but the published material does not justify the routine use of ultrasound in pregnant women."8
“According to perinatal epidemiologist Marsden Wagner, the safety of ultrasound has never been clinically proven. The editors of the Cochrane Database, a review of over 9,000 controlled trials from 85 different countries, note that "there has been surprisingly little well-organized research to evaluate possible adverse effects of ultrasound exposure on human fetuses."9
“In a 1999
study, six scientists at University College Dublin found that ultrasound
creates changes in cells. Patrick Brennan, the lead researcher, said, "It
has been assumed for a long time that ultrasound had no effect on cells. We now
have grounds to question that assumption."10 Further evidence
that ultrasound has an effect on cells is indicated in recent research that
shows a higher-than-average rate of left-handedness in boys exposed to
ultrasound in utero.11
Ultrasound
disrupts Blood Brain Barrier (BBB) and causes tissue damage in presence of
contrast agent in rabbits.
Some NLM recent
papers indicate they are using the disruption creatively with some
disregard for the long term permanent and delayed effects. Evidence of tissue
damage in one paper. No follow-up
on long term harms that show up later. Disruption of BBB allows drugs into the
brain and also makes brain more vulnerable to infection, perhaps permanently
more susceptible to meningitis.
Department of Medical Biophysics, University of Toronto, Sunnybrook Health Sciences Centre, 2075 Bayview Ave, Toronto, ON, Canada. khynynen@sri.utoronto.ca
Noninvasive, transient, and local image-guided blood-brain barrier disruption (BBBD) has been demonstrated with focused ultrasound exposure in animal models. Most studies have combined low pressure amplitude and low time average acoustic power burst sonications with intravascular injection of pre-formed micro-bubbles to produce BBBD without damage to the neurons. The BBB has been shown to be healed within a few hours after the exposure. The combination of focused ultrasound beams with MR image guidance allows precise anatomical targeting as demonstrated by the delivery of several marker molecules in different animal models. This method may in the future have a significant impact on the diagnosis and treatment of central nervous system (CNS) disorders. Most notably, the delivery of the chemotherapy agents (liposomal Doxorubicin and Herceptin) has been shown in a rat model.
PMID: 18486271 [PubMed - indexed for MEDLINE] http://www.ncbi.nlm.nih.gov/pubmed/18486271
Department of Medical Biophysics, University of Toronto, Sunnybrook Health Sciences Centre, 2075 Bayview Ave, Toronto, ON, M4N 3M5, Canada. khynynen@sri.utoronto.ca
Noninvasive, transient and local image-guided blood-brain barrier disruption can be accomplished using focused ultrasound exposure with intravascular injection of preformed microbubbles. MRI-guided blood-brain barrier disruption has been demonstrated and has been shown to heal in within a few hours after exposure. The delivery of several marker molecules has been demonstrated in different animal models with minimal or no damage to the brain tissue. Most notably, the delivery of antibodies and liposomal doxorubicin has been shown. The method may potentially open a new era in CNS drug delivery and perhaps also aid in molecular imaging and targeting. However, effective clinical devices and methods need to be developed further and the clinical feasibility demonstrated.
PMID: 17184160 [PubMed - indexed for MEDLINE] http://www.ncbi.nlm.nih.gov/pubmed/17184160
Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. kullervo@bwh.harvard.edu
The purpose of this study was to test the hypothesis that burst ultrasound (US) in the presence of a US contrast agent using parameters similar to those used in brain blood flow measurements causes tissue damage. The brains of 10 rabbits were sonicated in 3-8 locations with 1.5-MHz, 10- micro s bursts repeated at a frequency of 1 kHz at temporal peak acoustic pressure amplitudes ranging from 2 to 12.7 MPa. The total sonication time for each location was 20 s. Before each sonication, a bolus of US contrast agent was injected IV. Contrast-enhanced magnetic resonance (MR) images were obtained after the sonications to detect local enhancement in the brain. Whole brain histological evaluation was performed, and the sections were stained with hematoxylin and eosin (H and E), TUNEL, and vanadium acid fuchsin (VAF) staining to evaluate tissue effects, including apoptosis and ischemia. Both the magnetic resonance imaging (MRI) contrast enhancement and histology findings indicated that brain tissue damage was induced at a pressure amplitude level of 6.3 MPa. The damage included vascular wall damage, hemorrhage and, eventually, necrosis. Mild vascular damage was observed localized in a few microscopic tissue volumes in about half of the sonicated locations at all pressure values tested (down to 2 MPa). However, these sonications did not induce any detectable tissue effects, including ischemia or apoptosis. As a conclusion, the study showed that the US exposure levels currently used for blood flow measurements in brain are below the threshold of blood-brain barrier opening or brain tissue damage. However, one should be aware that brain damage can be induced if the exposure level is increased.
PMID: 12706199
[PubMed - indexed for MEDLINE] http://www.ncbi.nlm.nih.gov/pubmed/12706199
Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. kullervo@bwh.harvard.edu
The purpose of this study was to test the hypothesis that burst ultrasound in the presence of an ultrasound contrast agent can disrupt the blood-brain barrier (BBB) with acoustic parameters suitable for completely noninvasive exposure through the skull. The 10-ms exposures were targeted in the brains of 22 rabbits with a frequency of 690 kHz, a repetition frequency of 1 Hz, and peak rarefactional pressure amplitudes up to 3.1 MPa. The total exposure (sonication) time was 20 s. Prior to each sonication, a bolus of ultrasound contrast agent was injected intravenously. Contrast-enhanced MR images were obtained after the sonications to detect localized BBB disruption via local enhancement in the brain. Brain sections were stained with H&E, TUNEL, and vanadium acid fuchsin (VAF)-toluidine blue staining. In addition, horseradish peroxidase (HRP) was injected into four rabbits prior to sonications and transmission electron microscopy was performed. The MRI contrast enhancement demonstrated BBB disruption at pressure amplitudes starting at 0.4 MPa with approximately 50%; at 0.8 MPa, 90%; and at 1.4 MPa, 100% of the sonicated locations showed enhancement. The histology findings following 4 h survival indicated that brain tissue necrosis was induced in approximately 70-80% of the sonicated locations at a pressure amplitude level of 2.3 MPa or higher. At lower pressure amplitudes, however, small areas of erythrocyte extravasation were seen. The electron microscopy findings demonstrated HRP passage through vessel walls via both transendothelial and paraendothelial routes. These results demonstrate that completely noninvasive focal disruption of the BBB is possible.
PMID: 15588592 http://www.ncbi.nlm.nih.gov/pubmed/15588592
CA089017/CA/NCI NIH HHS/United States
CA76550/CA/NCI NIH HHS/United States
Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts. khynynen@sri.utoronto.ca
The goal of this study was to explore the feasibility of using low-frequency magnetic resonance (MR) image-guided focused ultrasound as a noninvasive method for the temporary disruption of the blood-brain barrier (BBB) at targeted locations.
Rabbits were placed inside a clinical 1.5-tesla MR imaging unit, and sites in their brains were targeted for 20-second burst sonications (frequency 260 kHz). The peak pressure amplitude during the burst varied between 0.1 and 0.9 MPa. Each sonication was performed after an intravenous injection of an ultrasound contrast agent (Optison). The disruption of the BBB was evaluated with the aid of an injection of an MR imaging contrast agent (MAG-NEVIST). Additional tests involving the use of MION-47, a 20-nm magnetic nanoparticle contrast agent, were also performed. The animals were killed at different time points between 3 minutes and 5 weeks postsonication, after which light or electron microscopic evaluation was performed. The threshold for BBB disruption was approximately 0.2 MPa. More than 80% of the brain sites sonicated showed BBB disruption when the pressure amplitude was 0.3 MPa; at 0.4 MPa, this percentage was greater than 90%. Tissue necrosis, ischemia, and apoptosis were not found in tissue in which the pressure amplitude was less than 0.4 MPa; however, in a few areas of brain tissue erythrocytes were identified outside blood vessels following exposures of 0.4 MPa or higher. Survival experiments did not show any long-term adverse events.
These results demonstrate that low-frequency ultrasound bursts can induce local, reversible disruption of the BBB without undesired long-term effects. This technique offers a potential noninvasive method for targeted drug delivery in the brain aided by a relatively simple low-frequency device.
PMEDID =16961141 http://www.ncbi.nlm.nih.gov/pubmed/16961141