Ultrasound Hazard
Search Cidpusa webUltrasound damages Infants
By Robert Uhlig, Technology Correspondent
New research has raised doubts over the safety of ultrasound scans used to view fetuses in the womb. Scientists have called for further research to determine whether safety limits should be reviewed for the tests, which are also used to check internal organs in children and adults. Since the early 1990s, when American researchers showed that ultrasound tissue heating can cause bleeding in mouse intestines, ultrasonographers tune the power of scans to reduce heating. The latest discovery, by scientists at University College Dublin, is the first to find that scans create changes in cells. Patrick Brennan, who led the research, said: "It has been assumed for a long time that ultrasound has no effect on cells. We now have grounds to question that assumption."
The researchers gave 12 mice an eight megahertz scan lasting for 15 minutes. Hospital scans can last for up to an hour, using frequencies of between three and 10 megahertz. According to today's New Scientist, two significant changes in the cells of the small intestine were detected in scanned mice compared with unscanned mice. Four and a half hours after exposure, the rate of cell division had reduced by 22 per cent and the rate of programmed cell death had approximately doubled. Mr Brennan believes there will be similar effects in humans.
By Dr. John Christopher
From Dr.J. R. Christopher's book: Every Woman's Herbal.
Forward courtesy of Hermes Trismegistus
More subtle, but potentially more dangerous, is the routine application of ultrasound in normal pregnancies. Although most medical practitioners assure us that ultrasound presents no dangers, this procedure, which is used to study the body's internal organs with non-ionizing waves, has been the subject of
research indicating some
considerable risks. Although supposedly said to work with sound waves, they are not in the audible range, so their high frequency is not natural to the body. Dr. Mendelsohn
wrote, "Ultrasound produces at least two biological effects--heat and a process called 'cavitation' in which bubbles are created that expand and contract in response to sound waves. The first time I saw this cavitation process in action, a
chiropractor turned on the therapeutic ultrasound machine in his office and placed a few drops of water on the part of the machine that was
applied to the patient. I wish every reader...could have been with me to watch that water suddenly boil and bubble" (The
People's Doctor, Vol.7, No. 11, p. 3).
After ferreting out the truth about ultrasound over the years, Dr. Mendelsohn received copies of documents researching the procedure, which anyone may receive by writing WHO Publications Center, 49 Sheridan Ave.,
Albany, NY 12210, asking for "Environmental Health Criteria 22: Ultrasound." Experiments cited in these documents indicated reduced fetal weight and reduced fetal organ weight in animals who received ultrasound. Researchers are noticing a small but definite reduction in newborn birth rate among human
infants exposed to ultrasound. The immune systems of laboratory animals exposed to the procedure are said to be affected. It also affects the blood platelets which allow the blood to clot. This could lead to problems with circulation because of
traveling blood clots. Changes in the structure and composition of cells, including genetic material, has been suspected. In experiments with animals, these changes have resulted in defective embryos with a variety of problems. Researchers postulate that problems incurred by ultrasound could take as long as 20 years to surface, including the possibility of cancer and, most commonly suspected, leukemia. The mother might also experience congenital malformations.
Study Shows Potential Dangers of Ultrasound in Fetal Development
Aug. 24, 2006
A new study reports that prolonged and frequent use of ultrasound on pregnant mice causes brain abnormalities in the developing mouse fetus. Researchers said that the study findings support warnings by the U.S. Food and Drug Administration against the use of medically nonindicated or commercial prenatal ultrasound videos.
While ultrasound generally is considered safe if properly used when information is needed about a pregnancy, the FDA has expressed concern over the burgeoning use of the technology for entertainment purposes, such as in "keepsake" pictures and videos.
There is evidence that the exposure of pregnant mice and nonhuman primates to ultrasound waves may affect the behavior of their exposed offspring. Additionally, studies have shown that the frequent exposure of the human fetus to ultrasound waves is associated with a decrease in newborn body weight, an increase in the frequency of left-handedness, and delayed speech.
Because ultrasound energy is a high-frequency mechanical vibration, researchers hypothesized that it might influence the migration of neurons in a developing fetus. Neurons in mammals multiply early in fetal development and then migrate to their final destinations. Any interference or disruption in the process could result in abnormal brain function.
In the study, researchers injected more than 335 fetal mice at embryonic day 16 with special markers to track neuronal development. Exposure to ultrasound waves for 30 minutes or longer caused a small but statistically significant number of neurons to remain scattered within inappropriate cortical layers and in the adjacent white matter. The magnitude of dispersion of labeled neurons was highly variable but increased with duration of exposure to ultrasound waves.
"We have observed that a small but significant number of neurons in the mouse embryonic brain do not migrate to their proper positions in the cerebral cortex following prolonged and frequent exposure to ultrasound," said Pasko Rakic, M.D., of the Yale School of Medicine in New Haven, Conn. The study appeared in the Aug. 7 edition of the Proceedings of the National Academy of Sciences.
Dr. Rakic emphasized that the study does not mean that ultrasound use on human fetuses for appropriate diagnostic and medical purposes should be abandoned.
"On the contrary: ultrasound has been shown to be very beneficial in the medical context," he said. "Instead, our study warns against its non-medical use."
The research team intends to conduct research on nonhuman primates to see if a similar effect is occurring in the developing larger brains, which are more similar to humans. Those upcoming studies should provide information that will be more directly applicable to uses of ultrasound waves in humans.
By Laurie Volkin and Richard S. Dargan, ASRT Contributing Writers
Multifocal neuropathy