scholarly journals Laser-nucleated acoustic cavitation in focused ultrasound

2011 ◽  
Vol 82 (4) ◽  
pp. 044902 ◽  
Author(s):  
Bjoern Gerold ◽  
Spiros Kotopoulis ◽  
Craig McDougall ◽  
David McGloin ◽  
Michiel Postema ◽  
...  
Keyword(s):  
Focused Ultrasound ◽  
Acoustic Cavitation

scholarly journals Nanoparticle-Mediated Acoustic Cavitation Enables High Intensity Focused Ultrasound Ablation Without Tissue Heating

2018 ◽  
Vol 10 (43) ◽  
pp. 36786-36795 ◽  
Author(s):  
Adem Yildirim ◽  
Dennis Shi ◽  
Shambojit Roy ◽  
Nicholas T. Blum ◽  
Rajarshi Chattaraj ◽  
...  
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
Acoustic Cavitation ◽  
High Intensity Focused Ultrasound ◽  
Tissue Heating ◽  
Ultrasound Ablation ◽  
Focused Ultrasound Ablation

scholarly journals Effects of Sub-Atmospheric Pressure and Dissolved Oxygen Concentration on Lesions Generated in Ex Vivo Tissues by High Intensity Focused Ultrasound

2020 ◽  
Author(s):  
Min He ◽  
Zhiqiang Zhong ◽  
Deping Zeng ◽  
Xiaobo Gong ◽  
Zhibiao Wang ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Atmospheric Pressure ◽  
High Intensity ◽  
Focused Ultrasound ◽  
Ambient Pressure ◽  
Acoustic Cavitation ◽  
High Intensity Focused Ultrasound ◽  
Dissolved Oxygen Concentration ◽  
Significant Difference

Abstract BackgroundAcoustic cavitation plays an important role in the medical treatment using high intensity focused ultrasound (HIFU), but unnecessarily strong cavitation also could deform the morphology and enlarge the size of lesions. It is known that the increase of ambient hydrostatic pressure (Pstat) can control the acoustic cavitation but the question how decrease of Pstat and dissolved oxygen concentration (DOC) influences the strength of cavitation has not been thoroughly answered.MethodsEx vivo bovine liver tissues were immersed in degassed water with different DOC of 1.0 mg/L, 1.5 mg/L and 2.0 mg/L. Ultrasound (US) of 1 MHz and the spatial and temporal average intensity (Isata) of 6500 W/cm2 was used to expose two groups of in vitro bovine livers for two seconds; one group was under atmospheric pressure (Pstat = 1 bar) and the other was under sub-atmospheric pressure (Pstat = 0.1 bar). Acoustic cavitation was detected by a passive cavitation detector (PCD) during the exposure process. Echo signals at the focal zone of HIFU were monitored by B-mode ultrasound imaging before and after exposure.ResultsThe results demonstrated a significant difference of broadband acoustic emissions from the cavitation bubbles, echo signals on B mode image, morphology of lesions under various condition of ambient pressure and DOC. The lesion volume in tissue was increased with the increase of ambient pressure and DOC.ConclusionCavitation could be suppressed through sub-atmospheric pressure and low DOC level in liver tissue, which could provide a method of controlling cavitation in HIFU treatment to avoid unpredictable lesions.

scholarly journals Acoustic Cavitation Enhances Focused Ultrasound Ablation with Phase-Shift Inorganic Perfluorohexane Nanoemulsions: AnIn VitroStudy Using a Clinical Device

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Lu-Yan Zhao ◽  
Jian-Zhong Zou ◽  
Zong-Gui Chen ◽  
Shan Liu ◽  
Jiao Jiao ◽  
...  
Keyword(s):  
Phase Shift ◽  
Focused Ultrasound ◽  
Continuous Wave ◽  
Acoustic Cavitation ◽  
High Intensity Focused Ultrasound ◽  
Inertial Cavitation ◽  
Hifu Ablation ◽  
Duty Cycles ◽  
Ultrasound Ablation ◽  
Phosphate Buffered Saline

Purpose.To investigate whether acoustic cavitation could increase the evaporation of a phase-shift inorganic perfluorohexane (PFH) nanoemulsion and enhance high intensity focused ultrasound (HIFU) ablation.Materials and Methods.PFH was encapsulated by mesoporous silica nanocapsule (MSNC) to form a nanometer-sized droplet (MSNC-PFH). It was added to a tissue-mimicking phantom, whereas phosphate buffered saline (PBS) was added as a control (PBS-control). HIFU (Pac=150 W,t=5/10 s) exposures were performed in both phantoms with various duty cycles (DC). US images, temperature, and cavitation emissions were recorded during HIFU exposure. HIFU-induced lesions were measured and calculated.Results.Compared to PBS-control, MSNC-PFH nanoemulsion could significantly increase the volume of HIFU-induced lesion (P<0.01). Peak temperatures were 78.16 ± 5.64°C at a DC of 100%, 70.17 ± 6.43°C at 10%, 53.17 ± 4.54°C at 5%, and 42.00 ± 5.55°C at 2%, respectively. Inertial cavitation was much stronger in the pulsed-HIFU than that in the continuous-wave HIFU exposure. Compared to 100%-DC exposure, the mean volume of lesion induced by 5 s exposure at 10%-DC was significantly larger, but smaller at 2%-DC.Conclusions.MSNC-PFH nanoemulsion can significantly enhance HIFU ablation. Appropriate pulsed-HIFU exposure could significantly increase the volume of lesion and reduce total US energy required for HIFU ablation.

Monitoring of acoustic cavitation in microbubble‐presented focused ultrasound exposure using gradient‐echo MRI

2019 ◽  
Vol 51 (1) ◽  
pp. 311-318 ◽  
Author(s):  
Chen‐Hua Wu ◽  
Hao‐Li Liu ◽  
Cheng‐Tao Ho ◽  
Po‐Hung Hsu ◽  
Ching‐Hsiang Fan ◽  
...  
Keyword(s):  
Focused Ultrasound ◽  
Acoustic Cavitation ◽  
Gradient Echo ◽  
Ultrasound Exposure

scholarly journals Effects of sub-atmospheric pressure and dissolved oxygen concentration on lesions generated in ex vivo tissues by high intensity focused ultrasound

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Min He ◽  
Zhiqiang Zhong ◽  
Deping Zeng ◽  
Xiaobo Gong ◽  
Zhibiao Wang ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Atmospheric Pressure ◽  
High Intensity ◽  
Focused Ultrasound ◽  
Ex Vivo ◽  
Ambient Pressure ◽  
Acoustic Cavitation ◽  
High Intensity Focused Ultrasound ◽  
Dissolved Oxygen Concentration ◽  
The Difference

Abstract Background Acoustic cavitation plays an important role in the medical treatment using high-intensity focused ultrasound (HIFU), but unnecessarily strong cavitation also could deform the morphology and enlarge the size of lesions. It is known that the increase of ambient hydrostatic pressure (Pstat) can control the acoustic cavitation. But the question of how the decrease of Pstat and dissolved oxygen concentration (DOC) influence the strength of cavitation has not been thoroughly answered. In this study, we aimed to investigate the relationship among the Pstat, DOC and the strength of cavitation. Methods Ex vivo bovine liver tissues were immersed in degassed water with different DOC of 1.0 mg/L, 1.5 mg/L and 2.0 mg/L. Ultrasound (US) of 1 MHz and the spatial and temporal average intensity (Isata) of 6500 W/cm2 was used to expose two groups of in vitro bovine livers for 2 s; one group was under atmospheric pressure (Pstat = 1 bar) and the other was under sub-atmospheric pressure (Pstat = 0.1 bar). Acoustic cavitation was detected by a passive cavitation detector (PCD) during the exposure process. Echo signals at the focal zone of HIFU were monitored by B-mode ultrasound imaging before and after exposure. The difference between two pressure groups was tested using paired sample t-test. The difference among different DOC groups was evaluated by one-way analysis of variance (ANOVA). Results The results demonstrated a significant difference of broadband acoustic emissions from the cavitation bubbles, echo signals on B-mode image, morphology of lesions under various conditions of ambient pressure and DOC. The lesion volume in tissue was increased with the increase of ambient pressure and DOC. Conclusion Cavitation could be suppressed through sub-atmospheric pressure and low DOC level in liver tissue, which could provide a method of controlling cavitation in HIFU treatment to avoid unpredictable lesions.

scholarly journals Pulsed focused ultrasound can improve the anti-cancer effects of immune checkpoint inhibitors in murine pancreatic cancer

2021 ◽  
Vol 18 (180) ◽  
pp. 20210266
Author(s):  
Petros X. E. Mouratidis ◽  
Marcia Costa ◽  
Ian Rivens ◽  
Elizabeth E. Repasky ◽  
Gail ter Haar
Keyword(s):  
Pancreatic Cancer ◽  
T Cells ◽  
Immune Checkpoint ◽  
Immune Checkpoint Inhibitors ◽  
Focused Ultrasound ◽  
Immune Cell ◽  
Checkpoint Inhibitors ◽  
Acoustic Cavitation ◽  
High Intensity Focused Ultrasound ◽  
Pulsed Focused Ultrasound

Pulsed high-intensity focused ultrasound (pHIFU) uses acoustic pressure to physically disrupt tumours. The aim of this study was to investigate whether pHIFU can be used in combination with immune checkpoint inhibitors (ICIs) to enhance survival of tumour-bearing animals. Murine orthotopic pancreatic KPC tumours were exposed both to a grid of pHIFU lesions (peak negative pressure = 17 MPa, frequency = 1.5 MHz, duty cycle = 1%, 1 pulse s −1 , duration = 25 s) and to anti-CTLA-4/anti-PD-1 antibodies. Acoustic cavitation was detected using a weakly focused passive sensor. Tumour dimensions were measured with B-mode ultrasound before treatment and with callipers post-mortem. Immune cell subtypes were quantified with immunohistochemistry and flow cytometry. pHIFU treatment of pancreatic tumours resulted in detectable acoustic cavitation and increased infiltration of CD8 + T cells in the tumours of pHIFU and pHIFU + ICI-treated subjects compared with sham-exposed subjects. Survival of subjects treated with pHIFU + ICI was extended relative to both control untreated subjects and those treated with either pHIFU or ICI alone. Subjects treated with pHIFU + ICI had increased levels of CD8 + IFNγ + T cells, increased ratios of CD8 + IFNγ + to CD3 + CD4 + FoxP3 + and CD11b + Ly6G + cells, and decreased CD11c high cells in their tumours compared with controls. These results provide evidence that pHIFU combined with ICI may have potential for use in pancreatic cancer therapy.

Sign in / Sign up

Export Citation Format

Share Document