Presentation on Histotripsy and Neurological Diseases

Introduction

• Presented by Dr. Chen Zhu, Associate Professor of Biomedical Engineering, University of Michigan.
• Focus on therapeutic ultrasound techniques, particularly histotripsy for cancer and neurological diseases.

Background on Histotripsy

• Developed in 2002 during Dr. Zhu's PhD with Dr. Charles King.
• Histotripsy uses ultrasound to mechanically liquefy target tissue.
• Non-invasive, non-ionizing, and non-thermal.
• Distinct from traditional ultrasound techniques that rely on heating the tissue.

Mechanism of Histotripsy

• Uses high-pressure, short ultrasound pulses at low duty cycles (below 1%).
• Generates cavitation microbubbles causing mechanical tissue disruption.
• Allows precise removal of tissue akin to real surgery.
• Two types: Cavitational Histotripsy (University of Michigan) and Boiling Histotripsy (University of Washington).

Instrumentation and Applications

• Utilizes a therapy transducer with integrated imaging capabilities.
• Compact system similar to ultrasound imaging equipment.

Applications in Neurological Diseases

• Transcranial histotripsy for brain treatment.
• Potential to minimize skull heating, allowing treatment of large volumes and locations.
• Initial safety studies show lesions are confined to treatment zones without excessive bleeding.

Focus Areas

• Intracerebral Hemorrhage (Hemorrhagic Stroke):

  • Quick liquefaction of clots via transcranial histotripsy.
  • Reduces surgery invasiveness and secondary injury.

• Treatment of Brain Tumors:

  • Potential to treat a wide range of tumor locations through skull.

Applications in Cancer Treatment

• Initial studies on liver cancer (primary and metastases).
• Histotripsy used for non-invasive ablation through chest and ribcage.
• Demonstrated potential in preclinical studies and a phase 1 clinical trial in humans.

Results

• Tumor volume significantly reduced and reabsorbed by body.
• Systemic and potent immune response observed.
• Abscopal effect noted in patients, indicating systemic immune activation.

Conclusion

• Histotripsy offers a promising alternative for treating cancer and neurological diseases.
• Potential for large-scale use with ongoing research and clinical trials.
• Encourages collaboration across various universities and institutions.

Q&A Highlights

• Questions on treatment near bone/air structures, phase aberration corrections.
• Concerns about controlling peak negative pressure to avoid unwanted effects.
• Interest in immune response from clinical trials on liver cancer.