Bulk ablation of soft tissue with intense ultrasound: Modeling and experiments

Mast, T. Douglas; Makin, Inder Raj S.; Faidi, Waseem; Runk, Megan M.; Barthé, Peter G.; Slayton, Michael H.

doi:10.1121/1.2011157

Cited by 52 publications

(56 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As shown in this result, the focal zone of the ultrasound beam was measured to be 1. The thermal effects of a focused field propagating through skin/superficial tissue have been extensively modeled using well-established acoustic beam propagation schemes [13][14][15][16] as well as using the bio-heat equation [15][16][17][18]. A multi-layer approach has been applied for numerical simulations, whereby the significant differences in tissue attenuation between the epidermis (nominal thickness 0.2 mm), dermis, and subcutaneous tissue have been accounted for.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Selective transcutaneous delivery of energy to porcine soft tissues using intense ultrasound (IUS)

White

Makin²,

Slayton³

et al. 2008

Lasers Surg Med

Self Cite

View full text Add to dashboard Cite

Objective: Various energy delivery systems have been utilized to treat superficial rhytids in the aging face. The Intense Ultrasound System (IUS) is a novel modality capable of transcutaneously delivering controlled thermal energy at various depths while sparing the overlying tissues. The purpose of this feasibility study was to evaluate the response of porcine tissues to various IUS energy source conditions. Further evaluation was performed of the built-in imaging capabilities of the device. Materials and Methods: Simulations were performed on ex vivo porcine tissues to estimate the thermal dose distribution in tissues after IUS exposures to determine the unique source settings that would produce thermal injury zones (TIZs) at given depths. Exposures were performed at escalating power settings and different exposure times (in the range of 1-7.6 J) using three IUS handpieces with unique frequencies and focal depths. Ultrasound imaging was performed before and after IUS exposures to detect changes in tissue consistency. Porcine tissues were examined using nitro-blue tetrazolium chloride (NBTC) staining sensitive for thermal lesions, both grossly and histologically. The dimensions and depth of the TIZs were measured from digital photographs and compared. Results: IUS can reliably achieve discrete, TIZ at various depths within tissue without surface disruption. Changes in the TIZ dimensions and shape were observed as source settings were varied. As the source energy was increased, the thermal lesions became larger by growing proximally towards the tissue surface. Maximum lesion depth closely approximated the pre-set focal depth of a given handpiece. Ultrasound imaging detected well-demarcated TIZ at depths within the porcine muscle tissue. Conclusion: This study demonstrates the response of porcine tissue to various energy dose levels of Intense Ultrasound. Further study, especially on human facial tissue, is necessary in order to understand the utility of this modality in treating the aging face and potentially, other cosmetic applications.

show abstract

Section: Numerical Simulationsmentioning

confidence: 99%

Selective transcutaneous delivery of energy to porcine soft tissues using intense ultrasound (IUS)

White

Makin²,

Slayton³

et al. 2008

Lasers Surg Med

Self Cite

View full text Add to dashboard Cite

show abstract

“…Models incorporating acoustic beam propagation and the bioheat equation (Pennes 1948) and thermal dose (Sapareto and Dewey 1984) provide excellent prediction of lesion location and extent on the average (Muratore et al 2003). However, because intervening and target tissues may be quite variable in their physical properties (scattering, refraction, absorption, speed-of-sound, perfusion), and because these properties may be temperature-dependent, beam intensity at the treatment site is difficult to predict (Mast et al 2005). …”

Section: Introductionmentioning

confidence: 99%

Improved visualization of high-intensity focused ultrasound lesions

Silverman

Muratore

Ketterling

et al. 2006

Ultrasound in Medicine & Biology

View full text Add to dashboard Cite

Spectral parameter imaging in both the fundamental and harmonic of backscattered radiofrequency (RF) data was used for immediate visualization of high-intensity focused ultrasound (HIFU) lesion sites. A focused 5-MHz HIFU transducer with a coaxial 9-MHz focused single-element diagnostic transducer was used to create and scan lesions in chicken breast and freshly excised rabbit liver. Bmode images derived from the backscattered RF signal envelope were compared with midband fit (MBF) spectral parameter images in the fundamental (9-MHz) and harmonic (18-MHz) bands of the diagnostic probe. Images of HIFU-induced lesions derived from the MBF to the calibrated spectrum showed improved contrast (~ 3 dB) of tumor margins versus surround compared to images produced from the conventional signal envelope. MBF parameter images produced from the harmonic band showed higher contrast in attenuated structures (core, shadow) compared to either the conventional envelope (3.3 dB core; 11.6 dB shadow) or MBF images of the fundamental band (4.4 dB core; 7.4 dB shadow). The gradient between the lesion and surround was 3.4 dB/mm, 6.9 dB/mm and 17.2 dB/mm for B-mode, MBF-fundamental mode and MBF-harmonic mode respectively. Images of threshold and 'popcorn' lesions produced in freshly excised rabbit liver were most easily visualized and boundaries best defined using MBF-harmonic mode.

show abstract

“…If x max is the maximum depth at which the ultrasound waves are still strong enough to cause significant heating, the mean heat deposited per unit volume over this distance is (Mast et al, 2005) Q ¼…”

Section: B Bubble-enhanced Heating In the Presence Of Blood Flowmentioning

confidence: 99%

“…Electronic mail: chandra.sehgal@uphs.upenn.edu vasculature and blood flow. Mast et al (2005) have considered perfusion related heat dissipation during direct heating by ultrasound. In this study we combine these two previous approaches to study heating induced by intravascular microbubbles under conditions of flow; the goal is to obtain a better understanding of the role of microbubble heating during antivascular ultrasound therapy.…”

Section: Introductionmentioning

confidence: 99%

Modeling of thermal effects in antivascular ultrasound therapy

Levenback

Sehgal

Wood

2012

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

Antivascular ultrasound consisting of low-intensity sonication in the presence of circulating microbubbles of an ultrasound contrast agent has been demonstrated to disrupt blood flow in solid cancers. In this study a mathematical framework is described for the microbubbleinduced heating that occurs during antivascular ultrasound. Biological tissues are modeled as a continuum of microbubble-filled vasculature, cells, and interstitial fluids with compressibility equal to the sum of the compressibility of each component. The mathematical simulations show that the absorption of ultrasound waves by viscous damping of the microbubble oscillations induced significant local heating of the tissue vasculature. The extent and the rate of temperature increase not only depends on the properties of the microbubbles and the sonication parameters but is also influenced markedly by the blood flow. Slow flow conditions lead to higher tissue temperatures due to a stronger interaction between microbubbles and ultrasound and reduced heat dissipation. Because tumors have slower blood flow than healthy tissue, the microbubble-induced ultrasound antivascular therapy is likely to affect cancerous tissue more extensively than healthy tissue, providing a way to selectively target the vasculature of cancers.

show abstract

Bulk ablation of soft tissue with intense ultrasound: Modeling and experiments

Cited by 52 publications

References 37 publications

Selective transcutaneous delivery of energy to porcine soft tissues using intense ultrasound (IUS)

Selective transcutaneous delivery of energy to porcine soft tissues using intense ultrasound (IUS)

Improved visualization of high-intensity focused ultrasound lesions

Modeling of thermal effects in antivascular ultrasound therapy

Contact Info

Product

Resources

About