PROJECT SUMMARY
The overall goal of this multi-institutional, multi-disciplinary grant is to bring histotripsy closer to widespread
human clinical use by developing a C-arm based platform to plan, target, and assess histotripsy ablations.
Histotripsy is a unique noninvasive, nonthermal, nonionizing and highly precise ablation modality that has
recently undergone a successful phase I clinical trial. Rodent studies demonstrate the promise of histotripsy to
potentiate an anti-cancer immune effect and combine synergistically with check-point inhibition. Although
histotripsy has highly promising therapeutic capability, a major barrier to adoption is the lack of a reliable
method for visualizing and targeting tumors. Systems to date have only used conventional ultrasound imaging
for targeting the tumor and monitoring and assessing the ablation zone. Unfortunately, ultrasound is operator
dependent, inherently limited for evaluating 3D tumors and ablation zones, unable to penetrate certain biologic
tissues such as bone and gas, and is of limited use in patients with large body habitus. Conventional CT and
MRI are not ideal for histotripsy due to limited space and field of view as well as artifacts from the therapeutic
transducer and robotic arm. C-arm x-ray fluoroscopy with cone-beam CT (CBCT) is an excellent option for
targeting during histotripsy and a C-arm based platform would complement current US guidance techniques.
C-arms are ubiquitous with world-wide distribution and expertise, have an open design with easy access to the
patient, provide volumetric data from CBCT for treatment planning and ablation zone assessment, and 2D
fluoroscopy can be adapted to deliver real-time automatic and accurate targeting. To advance histotripsy
toward widespread human clinical use, we will develop a C-arm fluoroscopic and CBCT based
approach that can be used to plan, target, and assess histotripsy ablations. Aim 1 of this grant will be to
develop and validate C-arm based algorithms to accurately and automatically target a specific volume of tissue
for histotripsy ablation. To improve the precision of histotripsy treatments, we will then develop respiratory
motion compensation techniques in Aim 2. Aim 3 will develop a deep-learning approach to compensate for the
variable speed of sound through different biologic tissues (analogous to aberration correction). In Aim 4, we will
integrate the developments from Aims 1-3 and perform prospective validation studies in human-scale porcine
and rabbit VX2 tumor models to determine the accuracy, efficacy and safety of C-arm guided histotripsy as
well as its effect on survival. If successful, this grant will catalyze the use of C-arm fluoroscopy with CBCT to
plan, target, and assess histotripsy of liver tumors, and bring the technique closer to widespread human clinical
use.