Simulation of enhanced heating of clinically relevant tissue volumes using nonlinear ultrasound waves generated by a multi-element HIFU phased array were conducted based on the combined Westervelt and bio-heat equations. A spatial spectral approach using the fast Fourier transform algorithm and a corresponding analytic solution to the bioheat equation were used to optimize temperature modeling in tissue. Localized shock-wave heating within a much larger treated tissue volume and short, single HIFU pulses within a much longer overall exposure time were accounted for in the algorithm. Separation of processes with different time and spatial scales made the calculations faster and more accurate. With the proposed method it was shown that for the same time-average power, the use of high peak power pulsing schemes that produce high-amplitude shocks at the focus result in faster tissue heating compared to harmonic, continuous-wave sonications. Nonlinear effects can significantly accelerate volumetric heating while also permitting greater spatial control to reduce the impact on surrounding tissues. Such studies can be further used to test and optimize various steering trajectories of shock-wave sonications for faster and more controlled treatment of tissue volumes.

1.
W.
Kreider
 et al.,
Characterization of a multi-element clinical HIFU system using acoustic holography and nonlinear modeling
,
IEEE UFFC
,
2013
,
60
(
8
),
1683
1698
.
2.
M.
Canney
 et al.,
Shock-induced heating and millisecond boiling in gels and tissue due to high intensity focused ultrasound
,
Ultrasound in Medicine & Biology
,
2010
,
36
(
2
),
250
267
.
3.
T. D.
Khokhlova
 et al.,
Controlled tissue emulsification produced by high intensity focused ultrasound shock waves and millisecond boiling
,
J. Acoust. Soc. Am.
,
2011
,
130
(
5
),
3498
3510
.
4.
V. A.
Khokhlova
 et al.,
Generation of volumetric boiling histotripsy lesions in tissue using a multi-element array of a clinical HIFU system
,
14th ISTU
,
Las Vegas
,
2014
.
5.
M. O.
Kohler
 et al. 
Volumetric HIFU ablation under 3D guidance of rapid MRI thermometry
,
Med. Phys.
2009
,
36
,
3521
3535
.
6.
J. L.
Dillenseger
and
S.
Esneault
,
Fast FFT-based bioheat transfer equation computation
,
Comput. Biol. Med.
2010
,
40
(
2
),
119
123
.
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