Huber CM. et al., 2025: Passive cavitation mapping for biomedical applications using higher order delay multiply and sum beamformer with linear complexity.
Christian Marinus Huber 1, Nicole Dorsch 2, Helmut Ermert 3, Martin Vossiek 2, Ingrid Ullmann 2, Stefan Lyer 3
1Department of Otorhinolaryngology, Head and Neck Surgery, Section of Experimental Oncology and Nanomedicine (SEON), Professorship for AI-Controlled Nanomaterials (KINAM), Universitätsklinikum Erlangen, Glücksstrasse 10a, Erlangen, 91054, Bavaria, Germany; Institute of Microwaves and Photonics (LHFT), Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstrasse 9, Erlangen, 91058, Bavaria, Germany. Electronic address:
2Institute of Microwaves and Photonics (LHFT), Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstrasse 9, Erlangen, 91058, Bavaria, Germany.
3Department of Otorhinolaryngology, Head and Neck Surgery, Section of Experimental Oncology and Nanomedicine (SEON), Professorship for AI-Controlled Nanomaterials (KINAM), Universitätsklinikum Erlangen, Glücksstrasse 10a, Erlangen, 91054, Bavaria, Germany.
Abstract
Ultrasound-induced cavitation can be used in various biomedical therapies, including localized drug delivery, sonoporation, gene transfer, noninvasive sonothrombolysis, lithotripsy, and histotripsy. It can also enhance thermal ablation of tumors and facilitate trans-blood-brain-barrier treatments. Accurate monitoring of cavitation activity, including dose and location, is essential for the safe and effective application of these therapies. Passive cavitation mapping (PCM) is a key technique used to achieve this. However, conventional Delay and Sum (DAS) beamforming methods suffer from low resolution and high side-lobe levels in standard diagnostic ultrasound transducer, limiting their effectiveness or are computationally expensive, in the case of robust capon beamformer (RCB). To address these challenges, we propose a higher-order nonlinear Delay Multiply and Sum (DMAS) beamformer for improved passive cavitation mapping. Our approach utilizes a novel implementation with linear complexity, using a determinant from symmetrical polynomials. Simulation and experimental results demonstrate that the proposed method enhances both axial and lateral point spread function, resolution and increasing image quality, while exhibiting linear complexity. These improvements suggest that higher-order nonlinear beamforming is a promising advancement for more accurate and reliable cavitation monitoring in biomedical applications.
Ultrasonics. 2025 Sep;153:107653. doi: 10.1016/j.ultras.2025.107653. Epub 2025 Apr 7.
PMID: 40203513 FREE ARTICLE
Comments 1
The phenomenon of cavitation is considered to play an important role in SWL and other biomedical applications. Collapsing cavitation bubbles are believed to be essential to fragment kidney stones into fine fragments after being broken by the Hopkinson`s effect into coarse pieces of several mm.
The paper describes a method to generate cavitation by a focused ultrasound transducer and the measurement by a linear array transducer. To detect cavitation events generated by the ultrasound source, a passive cavitation detection (PCD) is modified by a special beamforming program.
The improved beam forming algorithms are verified by computer simulations and experimental measurements on an ultrasound flow phantom. The spatial resolution of two different point sources could be improved.
In real SWL procedures cavitation may happen in the coupling area with fluid/gel of the shock wave transducer to the human body and, possibly, inside the body on the track to the target (e.g. kidney stone in the kidney). Cavitation at that point may help to fracture stones, but may in addition, cause micro bleedings and in rare cases hematomas.
To know more about the existence and distribution of cavitation bubbles as well as the effect on tissue and stones in the body would be great. The described method might be applied to real SWL.
However, the paper deals with cavitation generated by focused ultrasound and not by shock waves as used in SWL. Applicational problems may occur when the linear array shall be coupled to a patient body. The impact of this paper on SWL is considered minor.
Othmar Wess