Numerical Study of Bubble Cloud and Thermal Lesion Evolution During Acoustic Droplet Vaporization Enhanced Hifu Treatment

2021 ◽  
Author(s):  
Ying Xin ◽  
Aili Zhang ◽  
Lisa X. Xu ◽  
J. Brian Fowlkes
Keyword(s):  
Focused Ultrasound ◽  
Continuous Wave ◽  
Numerical Study ◽  
Wave Exposure ◽  
High Intensity Focused Ultrasound ◽  
Hifu Treatment ◽  
Thermal Lesion ◽  
Acoustic Droplet Vaporization ◽  
Droplet Vaporization ◽  
Bubble Cloud

Abstract Acoustic droplet vaporization (ADV) has proven to enhance high intensity focused ultrasound (HIFU) thermal ablation of tumor. It has also been demonstrated that triggering droplets before HIFU exposure could be a potential way to control both the size and the shape of the thermal lesion. In this paper, a numerical model is proposed to predict the thermal lesion created in ADV enhanced HIFU treatment. Bubble oscillation was coupled into a viscoelastic medium in the model to more closely represent real applications in tissues. Several physical processes caused by continuous wave ultrasound and elevated temperature during the HIFU exposure were considered, including rectified diffusion, gas solubility variation with temperature in the medium, boiling, etc. Four droplet concentrations spanning two orders of magnitude were calculated. The bubble cloud formed from triggering of the droplets by the pulse wave ultrasound, along with the evolution of the shape and location of the bubble cloud and thermal lesion during the following continuous wave exposure were obtained. The increase of bubble void fraction caused by continuous wave exposure were found to be consistent with the experimental observation. With the increase of droplet concentration, the predicted bubble cloud shapes vary from tadpole to triangular and double triangular, while the thermal lesions move toward the transducer. The results show that the assumptions used in this model increased the accuracy of the results. This model may be used for parametrical study of ADV enhanced HIFU treatment and be further used for treatment planning and optimization in the future.

scholarly journals The feasibility of a noise elimination method using continuous wave response of therapeutic ultrasound signals for ultrasonic monitoring of high-intensity focused ultrasound treatment

2021 ◽  
Author(s):  
Ryo Takagi ◽  
Toshikatsu Washio ◽  
Yoshihiko Koseki
Keyword(s):  
Noise Reduction ◽  
High Intensity ◽  
Focused Ultrasound ◽  
Continuous Wave ◽  
High Intensity Focused Ultrasound ◽  
Hifu Treatment ◽  
Noise Elimination ◽  
Tissue Samples ◽  
Wave Response ◽  
Failure Conditions

Abstract Purpose In this study, the robustness and feasibility of a noise elimination method using continuous wave response of therapeutic ultrasound signals were investigated when tissue samples were moved to simulate the respiration-induced movements of the different organs during actual high-intensity focused ultrasound (HIFU) treatment. In addition to that, the failure conditions of the proposed algorithm were also investigated. Methods The proposed method was applied to cases where tissue samples were moved along both the lateral and axial directions of the HIFU transducer to simulate respiration-induced motions during HIFU treatment, and the noise reduction level was investigated. In this experiment, the speed of movement was increased from 10 to 40 mm/s to simulate the actual movement of the tissue during HIFU exposure, with the intensity and driving frequency of HIFU set to 1.0–5.0 kW/cm2 and 1.67 MHz, respectively. To investigate the failure conditions of the proposed algorithm, the proposed method was applied with the HIFU focus located at the boundary between the phantom and water to easily cause cavitation bubbles. The intensity of HIFU was set to 10 kW/cm2. Results Almost all HIFU noise was constantly able to be eliminated using the proposed method when the phantom was moved along the lateral and axial directions during HIFU exposure. The noise reduction level (PRL in this study) at an intensity of 1.0, 3.0, and 5.0 kW/cm2 was in the range of 28–32, 38–40, and 42–45 dB, respectively. On the other hand, HIFU noise was not basically eliminated during HIFU exposure after applying the proposed method in the case of cavitation generation at the HIFU focus. Conclusions The proposed method can be applicable even if homogeneous tissues or organs move axially or laterally to the direction of HIFU exposure because of breathing. A condition under which the proposed algorithm failed was when instantaneous tissue changes such as cavitation bubble generation occurred in the tissue, at which time the reflected continuous wave response became less steady.

WE-E-304A-05: Acoustic Droplet Vaporization for Enhancement of High Intensity Focused Ultrasound Thermal Ablation

2009 ◽  
Vol 36 (6Part26) ◽  
pp. 2786-2787
Author(s):  
M Zhang ◽  
KJ Haworth ◽  
SD Swanson ◽  
ML Fabiilli ◽  
OD Kripfgans ◽  
...  
Keyword(s):  
High Intensity ◽  
Thermal Ablation ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Acoustic Droplet Vaporization ◽  
Droplet Vaporization

scholarly journals Acoustic Droplet Vaporization in Biology and Medicine

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Chung-Yin Lin ◽  
William G. Pitt
Keyword(s):  
Drug Delivery ◽  
Contrast Agent ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Superheated Liquid ◽  
Clinical Use ◽  
Vessel Occlusion ◽  
Acoustic Droplet Vaporization ◽  
Droplet Vaporization ◽  
Preclinical Trials

This paper reviews the literature regarding the use of acoustic droplet vaporization (ADV) in clinical applications of imaging, embolic therapy, and therapeutic delivery. ADV is a physical process in which the pressure waves of ultrasound induce a phase transition that causes superheated liquid nanodroplets to form gas bubbles. The bubbles provide ultrasonic imaging contrast and other functions. ADV of perfluoropentane was used extensively in imaging for preclinical trials in the 1990s, but its use declined rapidly with the advent of other imaging agents. In the last decade, ADV was proposed and explored for embolic occlusion therapy, drug delivery, aberration correction, and high intensity focused ultrasound (HIFU) sensitization. Vessel occlusion via ADV has been explored in rodents and dogs and may be approaching clinical use. ADV for drug delivery is still in preclinical stages with initial applications to treat tumors in mice. Other techniques are still in preclinical studies but have potential for clinical use in specialty applications. Overall, ADV has a bright future in clinical application because the small size of nanodroplets greatly reduces the rate of clearance compared to larger contrast agent bubbles and yet provides the advantages of ultrasonographic contrast, acoustic cavitation, and nontoxicity of conventional perfluorocarbon contrast agent bubbles.

scholarly journals Acoustic Droplet Vaporization for Enhancement of Thermal Ablation by High Intensity Focused Ultrasound

2011 ◽  
Vol 18 (9) ◽  
pp. 1123-1132 ◽  
Author(s):  
Man Zhang ◽  
Mario L. Fabiilli ◽  
Kevin J. Haworth ◽  
Frederic Padilla ◽  
Scott D. Swanson ◽  
...  
Keyword(s):  
High Intensity ◽  
Thermal Ablation ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Acoustic Droplet Vaporization ◽  
Droplet Vaporization

Numerical Study of Bubble Area Evolution During Acoustic Droplet Vaporization-Enhanced HIFU Treatment

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Ying Xin ◽  
Aili Zhang ◽  
Lisa X. Xu ◽  
J. Brian Fowlkes
Keyword(s):  
Treatment Time ◽  
Numerical Study ◽  
Dynamic Change ◽  
High Intensity Focused Ultrasound ◽  
Propagation Path ◽  
Experimental Result ◽  
Bubble Wall ◽  
Acoustic Droplet Vaporization ◽  
Treatment Protocols ◽  
Droplet Vaporization

Acoustic droplet vaporization has the potential to shorten treatment time of high-intensity focused ultrasound (HIFU) while minimizing the possible effects of microbubbles along the propagation path. Distribution of the bubbles formed from the droplets during the treatment is the major factor shaping the therapeutic region. A numerical model was proposed to simulate the bubble area evolution during this treatment. Using a linear acoustic equation to describe the ultrasound field, a threshold range was defined that determines the amount of bubbles vaporized in the treated area. Acoustic parameters, such as sound speed, acoustic attenuation coefficient, and density, were treated as a function of the bubble size distribution and the gas void fraction, which were related to the vaporized bubbles in the medium. An effective pressure factor was proposed to account for the influence of the existing bubbles on the vaporization of the nearby droplets. The factor was obtained by fitting one experimental result and was then used to calculate bubble clouds in other experimental cases. Comparing the simulation results to these other experiments validated the model. The dynamic change of the pressure and the bubble distribution after exposure to over 20 pulses of HIFU are obtained. It is found that the bubble area grows from a grainlike shape to a “tadpole,” with comparable dimensions and shape to those observed in experiments. The process was highly dynamic with the shape of the bubble area changing with successive HIFU pulses and the focal pressure. The model was further used to predict the shape of the bubble region triggered by HIFU when a bubble wall pre-exists. The results showed that the bubble wall helps prevent droplet vaporization on the distal side of the wall and forms a particularly shaped region with bubbles. This simulation model has predictive potential that could be beneficial in applications, such as cancer treatment, by parametrically studying conditions associated with these treatments and designing treatment protocols.

Treatment of murine tumors using acoustic droplet vaporization-enhanced high intensity focused ultrasound

2013 ◽  
Vol 58 (17) ◽  
pp. 6179-6191 ◽  
Author(s):  
Meili Zhu ◽  
Lixing Jiang ◽  
Mario L Fabiilli ◽  
Aili Zhang ◽  
J Brian Fowlkes ◽  
...  
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Acoustic Droplet Vaporization ◽  
Droplet Vaporization ◽  
Murine Tumors

scholarly journals High-Intensity Focused Ultrasound Treatment for Advanced Pancreatic Cancer

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yufeng Zhou
Keyword(s):  
Pancreatic Cancer ◽  
High Intensity ◽  
Focused Ultrasound ◽  
Advanced Pancreatic Cancer ◽  
High Intensity Focused Ultrasound ◽  
Treatment Modalities ◽  
Karnofsky Performance Scale ◽  
Great Success ◽  
Hifu Treatment ◽  
Performance Scale

Pancreatic cancer is under high mortality but has few effective treatment modalities. High-intensity focused ultrasound (HIFU) is becoming an emerging approach of noninvasively ablating solid tumor in clinics. A variety of solid tumors have been tried on thousands of patients in the last fifteen years with great success. The principle, mechanism, and clinical outcome of HIFU were introduced first. All 3022 clinical cases of HIFU treatment for the advanced pancreatic cancer alone or in combination with chemotherapy or radiotherapy in 241 published papers were reviewed and summarized for its efficacy, pain relief, clinical benefit rate, survival, Karnofsky performance scale (KPS) score, changes in tumor size, occurrence of echogenicity, serum level, diagnostic assessment of outcome, and associated complications. Immune response induced by HIFU ablation may become an effective way of cancer treatment. Comments for a better outcome and current challenges of HIFU technology are also covered.

Detection theory applied to high intensity focused ultrasound (HIFU) treatment evaluation

2003 ◽  
Vol 113 (4) ◽  
pp. 2308-2308
Author(s):  
Narendra Sanghvi ◽  
Adam Wunderlich ◽  
Ralf Seip ◽  
Jahangir Tavakkoli ◽  
Kris Dines ◽  
...  
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
Detection Theory ◽  
Treatment Evaluation ◽  
High Intensity Focused Ultrasound ◽  
Hifu Treatment
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