Effects of cavitation-enhanced heating in high-intensity focused ultrasound treatment on shear wave imaging

Iwasaki, Ryosuke; Nagaoka, Ryo; Takagi, Ryo; Goto, Kunihiko; Yoshizawa, Shin; Saijo, Yoshifumi; Umemura, Shin Ichiro

doi:10.7567/jjap.54.07hf11

Cited by 21 publications

(20 citation statements)

References 35 publications

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“…The above-described problem is expected to be overcome by utilizing such cavitation microbubbles. We have proposed cavitationenhanced HIFU treatment using an exposure sequence, [5][6][7][8] which we named the "trigger HIFU" sequence, consisting of a highly intense short "trigger pulse" to generate cavitation and an immediately following moderate-intensity long "sustaining burst" to oscillate the generated microbubbles. The effectiveness of the proposed exposure sequence has been confirmed in regard to the thermal effect of ultrasound.…”

Section: Introductionmentioning

confidence: 99%

Selective detection of cavitation bubbles by triplet pulse sequence in high-intensity focused ultrasound treatment

Iwasaki

Nagaoka

Yoshizawa

et al. 2018

Jpn. J. Appl. Phys.

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Acoustic cavitation bubbles are known to enhance the heating effect in high-intensity focused ultrasound (HIFU) treatment. The detection of cavitation bubbles with high sensitivity and selectivity is required to predict the therapeutic and side effects of cavitation, and ensure the efficacy and safety of the treatment. A pulse inversion (PI) technique has been widely used for imaging microbubbles through enhancing the second-harmonic component of echo signals. However, it has difficulty in separating the nonlinear response of microbubbles from that due to nonlinear propagation. In this study, a triplet pulse (3P) method was investigated to specifically image cavitation bubbles by extracting the 1.5th fractional harmonic component. The proposed 3P method depicted cavitation bubbles with a contrast ratio significantly higher than those in conventional imaging methods with and without PI. The results suggest that the 3P method is effective for specifically detecting microbubbles in cavitation-enhanced HIFU treatment.

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Section: Introductionmentioning

confidence: 99%

Selective detection of cavitation bubbles by triplet pulse sequence in high-intensity focused ultrasound treatment

Iwasaki

Nagaoka

Yoshizawa

et al. 2018

Jpn. J. Appl. Phys.

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“…A sequence called the Trigger HIFU sequence has been developed in previous studies [39][40][41][42] on bubble-enhanced HIFU heating, in which low-to medium-intensity ultrasound waves called heating bursts are irradiated to continuously vibrate bubbles immediately after generating cavitation clouds. In the sequence examined in this study, irradiation of focus B may have acted like a heating burst on the cloud at focus A.…”

Section: Discussionmentioning

confidence: 99%

Development of efficient method of generating reactive oxygen species by expanding cavitation region using ultrasound focus scanning in the direction of ultrasound propagation

Miyake

Umemura

Yoshizawa

2023

Jpn. J. Appl. Phys.

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Sonodynamic therapy (SDT) is a minimally invasive high-intensity focused ultrasound (HIFU) based therapy that combines a sonosensitizer and reactive oxygen species (ROS), which are produced by acoustic cavitation. In this paper, we experimentally examined the effectiveness of a proposed method of scanning the ultrasound focus in the direction of HIFU propagation for continuously generating cavitation clouds to expand the region of ROS generation and increase the amount of ROS. First, the continuous generation of cavitation bubbles was observed using a high-speed camera, and it was confirmed that bubbles could be generated even with a short-duration HIFU, which is difficult to generate bubbles by itself. Subsequently, we evaluated the area and amount of ROS generation by imaging sonochemiluminescence. Comparing the irradiation at 1 point with that at 7 points, the amount of ROS per acoustic energy increased by about 1.5 times, suggesting that it is an efficient method for ROS generation.

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“…The second factor, which is referred to as “difference between noise-eliminated signals and reference (DNER),” is the subtraction of averaged RF signal power at the fundamental component of HIFU between the noise-eliminated ( u sub ( t )) and reference ( u ref ( t )) RF signals acquired during the HIFU intermission period. DNER indicates the similarity between B-mode images after noise elimination and without HIFU exposure (reference) because the acquisition interval between RF signals with and without HIFU noise was 5 ms, and it is thought that there are few phantom changes within such a short time according to the literature [ 21 ]. DNER becomes lower when HIFU noise is eliminated effectively using the proposed method, i.e., DNER should serve as an indicator for evaluating the robustness of the proposed method in the case of tissue movement.…”

Section: Methodsmentioning

confidence: 99%

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

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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.

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Effects of cavitation-enhanced heating in high-intensity focused ultrasound treatment on shear wave imaging

Cited by 21 publications

References 35 publications

Selective detection of cavitation bubbles by triplet pulse sequence in high-intensity focused ultrasound treatment

Selective detection of cavitation bubbles by triplet pulse sequence in high-intensity focused ultrasound treatment

Development of efficient method of generating reactive oxygen species by expanding cavitation region using ultrasound focus scanning in the direction of ultrasound propagation

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

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