Tumors Partially Destroyed with Sound Don’t Come Back

Noninvasive sound technology developed at the University of Michigan (U-M) breaks down liver tumors in rats, kills cancer cells and spurs the immune system to prevent further spread—an advance that could lead to improved cancer outcomes in humans. By destroying only 50% to 75% of liver tumor volume, the rats’ immune systems were able to clear away the rest, with no evidence of recurrence or metastases in more than 80% of animals.

The 700kHz, 260-element histotripsy ultrasound array transducer used in Prof. Xu’s lab

Even if we don’t target the entire tumor, we can still cause the tumor to regress and also reduce the risk of future metastasis,” said Zhen Xu, professor of biomedical engineering at U-M and corresponding author of the study in Cancers. Results also showed the treatment stimulated the rats’ immune responses, possibly contributing to the eventual regression of the untargeted portion of the tumor and preventing further spread of the cancer.

The treatment, called histotripsy, noninvasively focuses ultrasound waves to mechanically destroy target tissue with millimeter precision. The relatively new technique is currently being used in a human liver cancer trial in the United States and Europe. In many clinical situations, the entirety of a cancerous tumor cannot be targeted directly in treatments for reasons that include the mass’ size, location or stage. To investigate the effects of partially destroying tumors with sound, this latest study targeted only a portion of each mass, leaving behind a viable intact tumor. It also allowed the team, including researchers at Michigan Medicine and the Ann Arbor VA Hospital, to show the approach’s effectiveness under less than optimal conditions.

Histotripsy is a promising option that can overcome the limitations of currently available ablation modalities and provide safe and effective noninvasive liver tumor ablation,” said Tejaswi Worlikar, a doctoral student in biomedical engineering. “We hope that our learnings from this study will motivate future preclinical and clinical histotripsy investigations toward the ultimate goal of clinical adoption of histotripsy treatment for liver cancer patients.”

Liver cancer ranks among the top 10 causes of cancer related deaths worldwide and in the U.S. Even with multiple treatment options, the prognosis remains poor with five-year survival rates less than 18% in the U.S. The high prevalence of tumor recurrence and metastasis after initial treatment highlights the clinical need for improving outcomes of liver cancer. Where a typical ultrasound uses sound waves to produce images of the body’s interior, U-M engineers have pioneered the use of those waves for treatment. And their technique works without the harmful side effects of current approaches such as radiation and chemotherapy.

Our transducer, designed and built at U-M, delivers high amplitude microsecond-length ultrasound pulses—acoustic cavitation—to focus on the tumor specifically to break it up,” Xu said. “Traditional ultrasound devices use lower amplitude pulses for imaging.”

Source: https://news.umich.edu/


An “unhackablecomputer chip lived up to its name in its first bug bounty competition, foiling over 500 cybersecurity researchers who were offered tens of thousands of dollars to analyze it and three other secure processor technologies for vulnerabilities. MORPHEUS, developed by computer science researchers at the University of Michigan, weathered the three-month virtual program DARPA dubbed the Finding Exploits to Thwart Tampering—or FETTBug Bounty without a single successful attack. In bug bounty programs, organizations or software developers offer compensation or other incentives to individuals who can find and report bugs or vulnerabilities.

DARPA, the Defense Advanced Research Projects Agency, partnered with the Department of Defense’s Defense Digital Service and Synack, a crowdsourced security platform, to conduct FETT, which ran from June through August 2020. It also tested technologies from MIT, Cambridge University, Lockheed Martin and nonprofit tech institute SRI International. The U-M team achieved its results by abandoning a cornerstone of traditional computer security—finding and eliminating software bugs, says team leader Todd Austin, the S. Jack Hu Collegiate Professor of Computer Science and Engineering. MORPHEUS works by reconfiguring key bits of its code and data dozens of times per second, turning any vulnerabilities into dead ends for hackers.

MORPHEUS blocks potential attacks by encrypting and randomly reshuffling key bits of its own code and data twenty times per second. 

Imagine trying to solve a Rubik’s Cube that rearranges itself every time you blink,” Austin said. “That’s what hackers are up against with MORPHEUS. It makes the computer an unsolvable puzzle.”

MORPHEUS has previously proven itself in the lab, but the FETT Bug Bounty marks the first time that it was exposed to a group of skilled cybersecurity researchers from around the globe. Austin says its success is further proof that computer security needs to move away from its traditional bugs-and-patches paradigm. “Today’s approach of eliminating security bugs one by one is a losing game,” he said. “Developers are constantly writing code, and as long as there is new code, there will be new bugs and security vulnerabilities. With MORPHEUS, even if a hacker finds a bug, the information needed to exploit it vanishes within milliseconds. It’s perhaps the closest thing to a future-proof secure system.”

For FETT, the MORPHEUS architecture was built into a computer system that housed a mock medical database. Computer experts were invited to try to breach it remotely. MORPHEUS was the second-most popular target of the seven processors evaluated.

Source: https://news.umich.edu/