Will ultrasound come to our homes?
Not only does it have the potential to become a consumer product, but new therapeutic uses for ultrasound could expand the technology into fields such as surgery, where doctors could cut flesh using ultrasound-generated bubbles.
“I would guess that 30 percent of all medicine is going to be ultrasound delivered, and more than that percent is going to be diagnosed” using ultrasounds, Carson tells DOTmed News.
Ultrasound is relatively inexpensive, doesn’t deliver ionizing radiation, and unlike MRI doesn’t require a 3 or 1-Tesla magnet and the associated shielding to operate, nor does it require cooling with helium, a rapidly depleting resource.
But there are hurdles to be cleared before ultrasound is ready for the home. While ultrasound at levels used in diagnostic work is not known to cause any harm, large-scale epidemiological studies have not been done, Carson says. These might be necessary before devices are put in the public’s hands, especially as the systems might end up being used for non-medical reasons.
Ultrasounds are also largely priced out of the consumer market. Even GE Healthcare’s smartphone-sized scanner, the Vscan, released a few years ago, costs about $8,000, according to published numbers.
But work is underway on cheaper systems — Newcastle University researchers, for instance, are trying to build a low-powered one for $65 for use in field work. More importantly, certain technical limitations are holding back the modality from its true potential, Carson says. However, he thinks the industry might not be too far away from a breakthrough.
Carson says for now, ultrasound would be hard to work with for a layperson, and it’s also closed off for some procedures: images have too many artifacts and too much speckle, the random, noisy interference generated by the reflected sound waves.
To really carry out the aberration correction needed to reduce artifacts and clear out the “clutter” or the scattering of the acoustic signals, more elements in the ultrasound transducer are needed. Many more. While most multiple-element commercial systems have at most 192 elements, Carson thinks they should have as many as 15,000. And each element needs to be attached to an electronic channel at as close to a one-to-one ratio as possible: for 15,000 elements, ideally you’d then need 15,000 electronic channels.
While this technology, if it comes about, is at least a decade away for professional systems, Carson says it would make for much cleaner images that generate more actionable data. They also could let ultrasound be used in more areas of the body, such as the brain.
“We don’t do much brain imaging now (with ultrasound), as the aberration is pretty bad,” Carson says. “But it’s a fairly easy aberration to correct if you have the right technology.”
But diagnosis is not enough. Carson says that any part of the body that can be imaged by ultrasound can possibly be treated with it, too.
Carson’s own team in Michigan has worked on using ultrasound for more effective drug delivery. In this, users direct ultrasound blasts to vaporize inert liquid droplets injected in the body. After vaporizing, an active drug contained within the inert droplet is then exposed, but only in the part of the body affected by the ultrasound. This means doctors can deliver much higher doses of drugs, potentially five times higher, Carson says.
Intriguingly, surgery might also be possible. Another team at Michigan, led by Drs. Charles Cain, Brian Fowlkes and Zhen Xu, has developed a technique they call histotripsy (literally, “tissue crushing”). Unlike HI-FU, another interventional ultrasound process that uses heat to the destroy tissue (in the U.S. it’s mainly used for uterine fibroids), this is a mechanical process. With it, ultrasound’s energy creates and breaks apart microbubbles, making a sort of virtual scalpel to liquefy flesh with fairly high accuracy.
“They make sharp-edged slices,” Carson says.
About three years ago, Cain, Fowlkes, Xu and others spun off the research into a start-up, Histosonics Inc., which so far has raised about $11 million to develop a product to be used on, at first, benign prostate growths.
Still, for all its bright future, if ultrasound is coming home, it’s still many years away — it will probably be about two decades before the technology is ready, Carson says.
“Making medicine more efficient is not a bad thing. It didn’t hurt medicine much for people to get thermometers (in their homes),” Carson tells DOTmed News. “We ought to be doing that with ultrasound.”