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'Invisible scalpel' could replace radiation treatment

By Ian Dillingham, Daily News Reporter
Published January 12, 2013

University researchers have demonstrated the effectiveness of a new technology that has the potential to dramatically improve surgical procedures.

Termed an “invisible scalpel," the laser-generated focused ultrasound seeks to improve the quality of non-invasive surgical procedures by turning high-energy lasers into ultrasound waves. The waves are then concentrated onto a single focal point where they can potentially destroy cancerous cells or tissue.

Engineering Prof. Jay Guo, one of the study's authors, said the innovation is similar to current cancer treatments using radiation with a significantly higher level of precision and potential for other applications.

“You can use it to kill cells,” Guo said. “You can (also) use the ultrasound to change to permittivity of the cell membranes, so you can deliver drugs through the cells’ membranes and treat the tissues and cells."

Some types of cancerous tumors are currently treated using radiation therapy. Guo said this method often destroys the targeted area but can also cause damage to the surrounding tissue.

Compared with radiation, however, Guo said the LGFU has the ability to target very specific areas, like a very small tumor, and to alleviate the collateral damage to healthy tissue.

“We’ve shown in our experiment that (the LGFU) can focus down to the size of a human hair,” Guo said. “In one experiment … we showed that you can detach the cells one by one, so it really localized with great precision.”

The technology behind the LGFU is currently used in several forms of photo-acoustic imaging, a method which combines optics technology with ultrasound. These images use similar technologies to the LGFU, but are taken at much lower energies, thus causing minimal damage to the tissue.

Hyoung Won Baac, a research fellow at Harvard who worked as a doctoral student in Guo’s lab, said the new technology also demonstrates a much greater level of accuracy than traditional methods.

“There is already a focused ultrasound technology nowadays routinely used in hospitals for therapeutic applications with several-millimeter accuracy,” Baac said. “But a main drawback of the classical equipment has been improved greatly by our work with a focal accuracy of smaller than 0.1 millimeters.”

Starting in 2010, the researchers at Guo’s lab began using carbon nanotubes to improve the performance. The tubes were then embedded in a polymer material that provides a better thermal expansion.

Even with these improvements, the device was still only capable of imaging given its low intensity.

“We need more improvement and verifications for more practical level of demonstration,” Baac said. “But if it works, the ultrasound surgery may work in a non-invasive, non-thermal and elaborate way. This will target tumors or problematic tissues exactly, keeping healthy nerves and blood vessels intact.”

As the researchers continue to improve the device, they hope to collaborate with the University of Michigan’s Medical School and other departments to help develop the technology for use on human subjects in the future.

“(The LGFU) has great potentials for high-accuracy therapy,” Baac said. “For practical use, we will collaborate with biomedical engineers and doctors to determine next targets and directions in clinical purposes."


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