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High intensity focused ultrasound (HIFU) ablation

High Intensity Focused Ultrasound (HIFU) shows considerable promise as a minimally invasive medical procedure, in applications such as tumor ablation, vessel cauterization, and 'bloodless' resection. In order to maximize the efficacy of HIFU procedures, and to minimize the damage to healthy tissue, it is important to predict tissue response through quantification of temperature rise during absorption of high-intensity ultrasound energy. In this regard, mathematical analyses of energy transfer during HIFU procedures are very valuable.

Characterization of HIFU transducers

Firstly velocity profiles are obtained using digitial particle image velocimetry (DPIV) and the intensity profile is obtained for the particular transducer using the optimization algorigthms. The velocity profile is shown below.


Effect of large blood vessels on the efficacy of HIFU ablation procedures

A three-dimensional computational model was developed for studying the efficacy of high intensity focused ultrasound (HIFU) procedures targeted near large blood vessels.  The model was first validated in a tissue phantom, to verify the absence of bubble formation and nonlinear effects.  Temperature rise and lesion-volume calculations were then performed for different beam locations and orientations relative to a large vessel.




Figure above shows the schematic of (a) No-flow model � no large blood vessel near the ablation region (b) Parallel flow model� blood vessel oriented parallel to the ultrasound beam axis and (c) Perpendicular flow model� blood vessel oriented perpendicular to the ultrasound beam axis.


Figure above shows the temperature rise (oC) as a function of radial distance (cm) at t = 10 and 20 sec (ultrasound is turned off after 10 sec) for no flow, parallel flow, and perpendicular flow models.







by zopeown last modified 2015-01-23 14:19