Two-dimensional phased arrays for surgery: Movement of a single focus

High-intensity focused ultrasound: advances in technology and experimental trials support enhanced utility of focused ultrasound surgery in oncology

“…Often elements are placed on a curved surface to achieve some geometric focusing [17,18]. The advantage of arrays is that the electrical signals applied to each element can be varied [19]. Using multichannel electronics, the acoustic fields produced by individual elements can be used coherently to produce a single focus that can be adjusted in size, shape and position and manoeuvred through a clinically relevant volume, or several foci can be created simultaneously.…”

Biomedical applications of acoustic radiation force based on somatosensory reception

“…One of the main aims of the current work was to propose and study using numerical modeling experiments an alternative way of developing such tactile displays based on the use of a two-dimensional array with elements randomly distributed on its surface (so called random array). Similar arrays were studied in detail in a series of previous papers [15][16][17][18][19][20], and it was demonstrated that such arrays have significant advantages over more common and very popular regular arrays with equidistant location of elements [21][22][23][24]. We have demonstrated [16][17][18][19][20] that irregularity in the element distribution over the array surface improves the quality of the acoustic and thermal fields generated by such arrays by reducing the level of secondary intensity maxima caused by the regular discrete structure of an array, and by increasing the capability to steer sets containing a relatively large number of foci along and off the array axis.…”

“…Similar arrays were studied in detail in a series of previous papers [15][16][17][18][19][20], and it was demonstrated that such arrays have significant advantages over more common and very popular regular arrays with equidistant location of elements [21][22][23][24]. We have demonstrated [16][17][18][19][20] that irregularity in the element distribution over the array surface improves the quality of the acoustic and thermal fields generated by such arrays by reducing the level of secondary intensity maxima caused by the regular discrete structure of an array, and by increasing the capability to steer sets containing a relatively large number of foci along and off the array axis. The ability of the arrays to generate simultaneously and move in space a large number of foci is the major advantage of two dimensional phased arrays [21,23,24], which, as shown, is implemented most effectively with the use of random arrays [16,[18][19][20].…”

Simulation study of the effects of near- and far-field heating during focused ultrasound uterine fibroid ablation using an electronically focused phased array: A theoretical analysis of patient safety

“…26 Sparse element distribution wherein interelement spacing exceeds λ/2 but with random or asymmetric positions is a partial solution, rendering arrays that reduce the generation of grating lobes. [27][28][29][30][31] Arrays built with these designs have been examined experimentally by Hand et al 32,33 and a version of this distribution method is included in the Sonalleve design. 14 The detriment of random sparse arrays, however, has been demonstrated through a simulation study by Ellens et al 34 and in a combined simulation and ex vivo study by Payne et al 35 In short, while the random positions of the sparse elements render the off-focus energy deposition incoherent and thus avoid grating lobes, they still produce significantly higher thermal deposition off-focus than either a flat λ/2 array or a single-element, spherically curved transducer.…”