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Brendon Nafziger, DOTmed News Associate Editor | August 30, 2013
From the September 2013 issue of HealthCare Business News magazine
“There’s no benefits to the patient; we’re looking histologically as to how accurate the technology is,” he says.
Interestingly, Chopra envisions the product as a single-use medical device, with the probe discarded after each use. As for the probe, it would carry eight transducers, each about 5-millimeters long, laid out in a line.
Chopra says he’s not alone. A 25-employee start-up, Profound Medical, which launched in 2008, licensed similar technology, and is also starting human trials in Canada using a Siemens MR platform.
Hyperthermia
Whether the prostate therapies pan out, MR-HIFU could also find a use as a secondary, adjunct therapy, according to Chopra. That is, for hyperthermia.
It’s been known for decades that poorly oxygenated cancers respond worse to radiation therapy. Yet by heating up the tissue, blood flow and oxygenation can be improved, thus boosting radiation therapy’s cancer-killing abilities. While hyperthermia adjunct techniques have been tried before and have failed, that’s largely because the body’s homeostatic mechanisms make it hard to keep the body at a constant high temperature using an external source, Chopra says. But MR-guided HIFU has an advantage: better thermometry. MR is able to accurately quantify the temperature in tissue, based in part on how water molecules react to heat, so an MR-guided treatment, by constantly monitoring and then modulating heat, could potentially make hyperthermia work. But, as with other technologies mentioned here, this is also in the very early stages.
“We’re just going to see some human studies start in the next few years,” Chopra predicts.
Surgery without the scalpel
HIFU relies on heat, but ultrasound causes non-thermal biological effects, too. It can also create microbubbles in tissue, a process known as cavitation. Generally, diagnostic ultrasound manufacturers work to create as little cavitation as possible. But almost a decade ago, researchers at the University of Michigan wondered what would happen if they turned the cavitation up to a high degree. The therapeutic potential of the resulting technology, which they call histotripsy (from “histo,” cell and “tripsy,” breakdown), is being explored in a Michigan spinoff, called HistoSonics.
The technique, developed by Drs. Charles Cain, Brian Fowlkes, Tim Hall, Zhen Xu and William Roberts, all from the University of Michigan, was originally investigated for use in in utero treatments on babies with heart defects. But the company is now at work on commercializing a device to treat benign prostate hyperplasia (BPH), otherwise known as an enlarged prostate. In this, non-cancerous prostate growth makes urination difficult.
