Acute and Chronic Bioeffects of Single and Multiple Doses of Piezoelectric Shockwaves (EDAP LT.01)

Ryan, P. C.; Jones, Bleddyn; Kay, Elaine W.; Nowlan, Peter; Kiely, E. A.; Gaffney, Eoin F.; Butler, Michael R.

doi:10.1016/s0022-5347(17)38352-0

Cited by 29 publications

(8 citation statements)

References 20 publications

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“…From this era, there is a report of the anecdotal observation of fewer subcapsular hematomas in patients treated at a rate of 75 v 7200 SW/min. 23 A laboratory study of renal injury in rabbits treated with a piezoelectric lithotripter describes more vascular trauma in animals treated at 1200 SW/min than those treated at 150 SW/min, 24 and a study performed using a research electrohydraulic lithotripter 25 showed a substantial increase in renal injury in dogs treated at 600 SW/min compared with the more conventional rate of 60 SW/min. These reports suggest that SW rate is a factor in renal injury, but by current standards, the conditions of treatment were extreme.…”

Section: Figmentioning

confidence: 99%

Why Stones Break Better at Slow Shockwave Rates Than at Fast Rates: In Vitro Study with a Research Electrohydraulic Lithotripter

Pishchalnikov

McAteer

Williams

et al. 2006

Journal of Endourology

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Cavitation bubbles do not persist between SWs. Thus, mature bubbles from one pulse do not interfere with the next pulse, even at 120 SW/min. However, cavitation nuclei carried by fine particles released from stones can persist between pulses. These nuclei have little effect on the compressive wave but seed cavitation under the influence of the tensile wave. Bubble growth draws energy from the negative-pressure phase of the SW, reducing its amplitude. This likely affects the dynamics of cavitation bubble clusters at the stone surface, reducing the effectiveness of bubble action in stone comminution.

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Section: Figmentioning

confidence: 99%

Why Stones Break Better at Slow Shockwave Rates Than at Fast Rates: In Vitro Study with a Research Electrohydraulic Lithotripter

Pishchalnikov

McAteer

Williams

et al. 2006

Journal of Endourology

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“…The growth of the persistent bubbles can detract energy from the shock waves and shield the energy delivery to the stone surface (Pishchalnikov et al 2006), resulting in inefficient stone fragmentation (Weir et al 2000; Paterson et al 2002; Madbouly et al 2005; Yilmaz et al 2005). The excess bubbles can also cause more renal damage (Delius and Brendel 1988; Delius et al 1988; Ryan et al 1991). In histotripsy, similar pressure levels are used to generate cavitation for tissue fractionation.…”

Section: Introductionmentioning

confidence: 99%

An Efficient Treatment Strategy for Histotripsy by Removing Cavitation Memory

Wang

Hall

et al. 2012

Ultrasound in Medicine & Biology

118

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Cavitation memory effects occur when remnants of cavitation bubbles (nuclei) persist in the host medium and act as seeds for subsequent events. In pulsed cavitational ultrasound therapy, or histotripsy, this effect may cause cavitation to repeatedly occur at these seeded locations within a target volume, producing inhomogeneous tissue fractionation or requiring an excess number of pulses to completely homogenize the target volume. We hypothesized that by removing the cavitation memory, i.e., the persistent nuclei, the cavitation bubbles could be induced at random locations in response to each pulse; therefore, complete disruption of a tissue volume may be achieved with fewer pulses. To test the hypothesis, the cavitation memory was passively removed by increasing the intervals between successive pulses, Δt, from 2, 10, 20, 50 and 100, to 200 ms. Histotripsy treatments were performed in red blood cell tissue phantoms and ex vivo livers using 1-MHz ultrasound pulses of 10 cycles at P−/P+ pressure of 21/59 MPa. The phantom study allowed for direct visualization of the cavitation patterns and the lesion development process in real time using high-speed photography; the ex vivo tissue study provided validation of the memory effect in real tissues. Results of the phantom study showed an exponential decrease in the correlation coefficient between cavitation patterns in successive pulses from 0.5 ± 0.1 to 0.1 ± 0.1 as Δt increased from 2–200 ms; correspondingly, the lesion was completely fractionated with significantly fewer pulses for longer Δts. In the tissue study, given the same number of therapy pulses, complete and homogeneous tissue fractionation with well-defined lesion boundaries was achieved only for Δt ≥ 100 ms. These results indicated that the removal of the cavitation memory resulted in more efficient treatments and homogeneous lesions.

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“…This finding could mark a potentially significant change in how patients will be treated by SWL in the future. Historically, there has been great interest within the SWL community in finding ways to perform treatment as rapidly as possible [7][8][9]. However, slowing the firing rate breaks stones more efficiently [1][2][3][10][11][12][13] and also appears to cause less injury to the kidney [14,15].…”

Section: Introductionmentioning

confidence: 99%

Effect of firing rate on the performance of shock wave lithotriptors

2008

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multiframe high-speed camera (Imacon 200, DRS Data & Imaging Systems, Inc., Oakland, NJ, USA) was used to follow the evolution of bubbles throughout the cavitation cycle. RESULTSFiring rate had little effect on the leading positive-pressure phase of the SWs with the DoLi lithotriptor. A slight reduction ( ≈ 7%) of peak positive pressure (P + ) was detected only in the very dense cavitation fields ( ≈ 1000 bubbles/cm 3 ) generated at the fastest firing rate (120 SW/min) in nondegassed water. The negative pressure of the SWs, on the other hand, was dramatically affected by firing rate. At 120 SW/min the peak negative pressure was reduced by ≈ 84%, the duration and area of the negative pressure component was reduced by ≈ 80% and ≈ 98%, respectively, and the energy density of negative pressure was reduced by > 99%. Whereas cavitation bubbles proliferated at fast firing rates, HS-camera images showed the bubbles that persisted between SWs were very small ( < 10 µ m). Similar results were obtained with the XX-ES lithotriptor but only after recognizing a ratedependent charging artefact with that machine. CONCLUSIONIncreasing the firing rate of a lithotriptor can dramatically reduce the negative pressure component of the SWs, while the positive pressure remains virtually unaffected. Cavitation increases as the firing rate is increased but as the bubbles collapse, they break into numerous microbubbles that, because of their very small size, do not pose a barrier to the leading positive pressure of the next SW. These findings begin to explain why stone breakage in SWL becomes less efficient as the firing rate is increased. KEYWORDSshock wave lithotripsy, cavitation bubbles, acoustic output Study Type -Therapy (case control) Level of Evidence 3a OBJECTIVETo determine the mechanism that underlies the effect of shock wave (SW) rate on the performance of clinical lithotripters.

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Acute and Chronic Bioeffects of Single and Multiple Doses of Piezoelectric Shockwaves (EDAP LT.01)

Cited by 29 publications

References 20 publications

Why Stones Break Better at Slow Shockwave Rates Than at Fast Rates: In Vitro Study with a Research Electrohydraulic Lithotripter

Why Stones Break Better at Slow Shockwave Rates Than at Fast Rates: In Vitro Study with a Research Electrohydraulic Lithotripter

An Efficient Treatment Strategy for Histotripsy by Removing Cavitation Memory

Effect of firing rate on the performance of shock wave lithotriptors

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