Suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound
Extracorporeal shock wave lithotripsy (ESWL) has been used as an effective modality to fragment kidney calculi. Because of the bubble shielding effect in the pre-focal region, the acoustic energy delivered to the focus is reduced. Low pulse repetition frequency (PRF) will be applied to dissolve thes...
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sg-ntu-dr.10356-795542023-03-04T17:13:46Z Suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound Wang, Jen-Chieh Zhou, Yufeng School of Mechanical and Aerospace Engineering DRNTU::Engineering::Mechanical engineering::Mechatronics Extracorporeal shock wave lithotripsy (ESWL) has been used as an effective modality to fragment kidney calculi. Because of the bubble shielding effect in the pre-focal region, the acoustic energy delivered to the focus is reduced. Low pulse repetition frequency (PRF) will be applied to dissolve these bubbles for better stone comminution efficiency. In this study, low intensity pulsed ultrasound (LIPUS) beam was aligned perpendicular to the axis of a shock wave (SW) lithotripter at its focus. The light transmission was used to evaluate the compressive wave and cavitation induced by SWs without or with a combination of LIPUS for continuous sonication. It is found that bubble shielding effect becomes dominated with the SW exposure and has a greater significant effect on cavitation than compressive wave. Using the combined wave scheme, the improvement began at the 5th pulse and gradually increased. Suppression effect on bubble shielding is independent on the trigger delay, but increases with the acoustic intensity and pulse duration of LIPUS. The peak negative and integral area of light transmission signal, which present the compressive wave and cavitation respectively, using our strategy at PRF of 1 Hz are comparable to those using SW alone at PRF of 0.1 Hz. In addition, high-speed photography confirmed the bubble activities in both free field and close to a stone surface. Bubble motion in response to the acoustic radiation force by LIPUS was found to be the major mechanism of suppressing bubble shielding effect. There is a 2.6-fold increase in stone fragmentation efficiency after 1,000 SWs at PRF of 1 Hz in combination with LIPUS. In summary, combination of SWs and LIPUS is an effective way of suppressing bubble shielding effect and, subsequently, improving cavitation at the focus for a better outcome. Accepted version 2014-11-04T07:18:44Z 2019-12-06T13:28:10Z 2014-11-04T07:18:44Z 2019-12-06T13:28:10Z 2014 2014 Journal Article Wang, J.-C., & Zhou, Y. (2015). Suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound. Ultrasonics, 55, 65-74. 0041-624X https://hdl.handle.net/10356/79554 http://hdl.handle.net/10220/24172 10.1016/j.ultras.2014.08.004 en Ultrasonics © 2014 Elsevier B.V. This is the author created version of a work that has been peer reviewed and accepted for publication by Ultrasonics, Elsevier B.V. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1016/j.ultras.2014.08.004]. 36 p. application/pdf application/pdf |
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DRNTU::Engineering::Mechanical engineering::Mechatronics Wang, Jen-Chieh Zhou, Yufeng Suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound |
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Extracorporeal shock wave lithotripsy (ESWL) has been used as an effective modality to fragment kidney calculi. Because of the bubble shielding effect in the pre-focal region, the acoustic energy delivered to the focus is reduced. Low pulse repetition frequency (PRF) will be applied to dissolve these bubbles for better stone comminution efficiency. In this study, low intensity pulsed ultrasound (LIPUS) beam was aligned perpendicular to the axis of a shock wave (SW) lithotripter at its focus. The light transmission was used to evaluate the compressive wave and cavitation induced by SWs without or with a combination of LIPUS for continuous sonication. It is found that bubble shielding effect becomes dominated with the SW exposure and has a greater significant effect on cavitation than compressive wave. Using the combined wave scheme, the improvement began at the 5th pulse and gradually increased. Suppression effect on bubble shielding is independent on the trigger delay, but increases with the acoustic intensity and pulse duration of LIPUS. The peak negative and integral area of light transmission signal, which present the compressive wave and cavitation respectively, using our strategy at PRF of 1 Hz are comparable to those using SW alone at PRF of 0.1 Hz. In addition, high-speed photography confirmed the bubble activities in both free field and close to a stone surface. Bubble motion in response to the acoustic radiation force by LIPUS was found to be the major mechanism of suppressing bubble shielding effect. There is a 2.6-fold increase in stone fragmentation efficiency after 1,000 SWs at PRF of 1 Hz in combination with LIPUS. In summary, combination of SWs and LIPUS is an effective way of suppressing bubble shielding effect and, subsequently, improving cavitation at the focus for a better outcome. |
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School of Mechanical and Aerospace Engineering |
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School of Mechanical and Aerospace Engineering Wang, Jen-Chieh Zhou, Yufeng |
format |
Article |
author |
Wang, Jen-Chieh Zhou, Yufeng |
author_sort |
Wang, Jen-Chieh |
title |
Suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound |
title_short |
Suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound |
title_full |
Suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound |
title_fullStr |
Suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound |
title_full_unstemmed |
Suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound |
title_sort |
suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound |
publishDate |
2014 |
url |
https://hdl.handle.net/10356/79554 http://hdl.handle.net/10220/24172 |
_version_ |
1759853766069190656 |