Two studies in Sweden by the same group have found high rates of defects in ultrasound machines used to scan pregnant women. The line of research began when doctors at the Karolinska Hospital discovered that many of their ultrasound machines were malfunctioning.
The first study examined about 700 machines from 7 manufacturers. About 40% had defective transducers — the only element tested. “The high error frequency and the risk for incorrect medical decisions when using a defective transducer indicate an urgent need for increased testing of the transducers in clinical departments,” the authors concluded.
The second study tried to find out how fast the machines break. The researchers examined about 300 machines all of which were working correctly (or had been fixed to work correctly) a year earlier. The retest showed that about 30% were defective. Apparently they break easily — and nobody notices.
These are lower bounds on the defect rate of the whole machine because only one part of it was tested. Because one part of the machine breaks so easily without detection, it makes me worry about the part of the machine that determines the strength of the ultrasound. How often is the actual strength much higher than the intended strength?
Caroline Rodgers has argued that ultrasound is a plausible cause of autism. A 2010 epidemiological study found no link between autism and ultrasound but these high defect rates call that study into question. In that study, almost all children (about 90%) had had experienced ultrasound before birth. This means that lack of correlation with autism means lack of correlation of number of scans (1 or more) with autism. This leaves open the possibility that it only takes one scan from a defective machine to produce autism. If that were true, and each child scanned repeatedly by the same machine (e.g., if a child has three scans, all are from the same machine), there would be no correlation between autism rate and number of scans.
These results scare me. It isn’t just ultrasound and autism. I blogged a few weeks ago about gross dosage errors in CT scans, some patients getting 10 times the intended dose of radiation. Here is another example where the operators of dangerous medical devices had no clue about appropriate testing and maintenance.
Thanks to Emily Williams who sent me a paper that mentioned these studies.
More about the ultrasound/autism link. Association between prenatal ultrasound and lefthandedness, which implies that ultrasound affects fetal brain development.
I need ultrasound sudies on my heart and CT scans on my head. Should I be worried?
Why am I not surprised?
In the clinical lab, QC is the rule on every piece of equipment for every test, daily or sometimes once every 8 hours. It seems like no one was doing any quality control testing on these ultrasound instruments.
I don’t know. But the next time I am asked to have dental X-rays made I will ask to see the maintenance/testing records.
Are dental x-rays really necessary? BTW, do you remember back in the 1950s when shoes stores had x-ray machines that let you see how well your feet fit in shoes? I think I would prefer that my feet get zapped for that sensible purpose instead of my head getting zapped.
A very good question.
In regards to dental x-rays, I believe people on the fence about them should look to another theme of this blog: hormesis. I, for one, am not too worried.
The ultrasound topic strikes me as altogether more sinister. Has anyone had experience taking a skeptical attitude to these tests? I imagine the pushback from the docs would be extreme.
yeah, I am not worried so long as the machine is working properly. If it is not working properly…
Good question. I also wonder what happens if you take a skeptical attitude toward the machines themselves (“when was the last time this machine was tested?”).
Prenatal ultrasound may be hazardous for developing babies because ultrasound involves heat, sound and vibration, all or any of which can interfere with normal brain development. During the prenatal period, the developing human is most vulnerable to any environmental insult, either chemical (pesticides, industrial chemicals) or physical (radiation, ultrasound). The use of prenatal ultrasound has increased dramatically over the past 30 years as has the prevalence of autism. Yet the focus of most research into causes of autism has been primarily genetics and chemical exposures.However, there is considerable research showing cause for concern and you can find abstracts of the studies at https://www.ultrasound-autism.org You can also find Caroline Rodgers excellent powerpoint presentation The Elephant in the Room at https://iacc.hhs.gov/events/2010/full-committee-mtg-slides-Oct22.shtml
Ultrasound may be safe for adults whose body systems are fully developed but it can severely affect developing babies.