Until now, health practitioners have mostly limited ultrasound to treating prostate cancer, bone metastases and uterine myoma, according to the Fraunhofer Institute (Bremen, Germany). Organs that move when a patient breathes are trickier, with doctors telling patients to hold their breath or putting the patients under anesthesia.
The Trans-Fusimo project – a Fraunhofer-coordinated effort including 11 research institutions in 7 countries – developed a new ultrasound therapy concept. The patient lies in an MRI producing an image of the liver’s position every 10th of a second while an ultrasound transducer with more than 1,000 small transmitters sits on the stomach. The MRI scanner controls the process, ensuring that the transducer only cooks the tumor cells and not healthy tissue.
A major challenge for Trans-Fusimo involved developing highly reliable software that could run in real time to determine the path of the focused ultrasound, ensuring the ultrasound reaches the liver tumor even when the patient moves.
“Generating an image of the liver’s position every 10thh of a second is not fast enough to reliably direct the ultrasound beam. This is why we developed software that can see into the immediate future and calculate the next position of the treated region,” said project manager Sabrina Haase, a mathematician at Fraunhofer MEVIS, in a news release.
The Trans-Fusimo team also had to prevent damage to the ribs sitting in front of the liver. They accomplished this by deactivating ultrasound transducer elements that would have hit the ribs.
The researchers have completed technical development and conducted preliminary tests, in which focused ultrasound was tested on a gel model that a robotic arm moved back and forth in an MR scanner to simulate liver movement in the body. “We have completed the technical development phase and have already run preliminary tests,” Haase said. In the test, a robotic arm moved a gel model back and forth in the MR scanner to simulate the liver movement inside the body. At the same time, the gel phantom was exposed to focused ultrasound, and the MRI scanner monitored the temperature distribution. “The results match our expectations,” says Haase. “Now, we can pursue the next steps.”
“The results match our expectations,” Haase said. “Now, we can pursue the next steps.”
The researchers plan to test the system on human patients in mid-2018, followed by medical product certification with an industry partner. They see promise using the ultrasound system to treat other organs including the kidney and pancreas – even the lungs.
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