Measurement and simulation of steered acoustic fields generated by a multielement array for therapeutic ultrasound

This data was collected to evaluate the effect of element size, element
positions, relative source pressure variations, and electrical crosstalk on the
accuracy of modelling pressure fields generated by a 555 kHz 32-element
ultrasonic array.

The transducer was assembled from 32 individual 3mm diameter plane
circular piezo-ceramic elements (XDR107, Sonic Concepts, Bothell, WA) arranged
in a pseudorandom configuration in a three-dimensional (3D) printed spherical
cap holder, with radius of curvature 80mm and aperture diameter 70 mm.

Measurements were performed with a 0.2 mm PVDF needle hydrophone
(Precision Acoustics) to characterise the source under quasi steady state
conditions (35 cycle burst).

All measurements were acquired using an automated scanning
tank filled with degassed, deionised water. The transducer was mounted in a
fixed xyz position. Hydrophones were mounted on an automated xyz stage, with
manual tilt, rotate adjustment.

Planar scans in the prefocal region were obtained to charaterise the
source under 3 driving conditions: with all elements driven with equal
amplitude and phase, with phase corrections applied which were obtained from
hydrophone measurements at the geometric focus position, and with these
corrections plus further geometrically calculated phase offsets to steer the
array focus to x = 20 mm, y = -20 mm. A further set of line scans passing
through the focus was obtained for the equalised unsteered case, focal steering
to x = -20 mm y = 20 mm, and 8 further steered focal positions.

In total, this study contains 33 datasets contained in 1 file, the
corresponding figure or table in the paper is given in brackets.

1.
Planar scan at 56 mm, unsteered without phase
corrections

2.
Planar scan at 56 mm, unsteered with phase
corrections from hydrophone measurements at geometric focus (Fig 1)

3-5.
X,Y,Z line scans through the focus, unsteered
with phase corrections

6. Planar scan at 50 mm, with phase corrections
+ steered to x = 20 mm, y = 20 mm

7-9 X,Y,Z line scans through the focus, with phase
corrections + steered to x = 20 mm, y = 20 mm

10-12 X,Y,Z line scans through the focus, with
phase corrections + steered to z = 100 mm (Fig 2a)

13-15 X,Y,Z line scans through the focus, with
phase corrections + steered to z = 70 mm

16-18 X,Y,Z line scans through the focus, with
phase corrections + steered to x = 5 mm

19-21 X,Y,Z line scans through the focus, with
phase corrections + steered to x = 10 mm

22-24 X,Y,Z line scans through the focus, with
phase corrections + steered to x = 20 mm (Fig 2b)

25-27 X,Y,Z line scans through the focus, with
phase corrections + steered to x = 40 mm (Fig 2c)

28-30 X,Y,Z line scans through the focus, with
phase corrections + steered to y = -10 mm

31-33 X,Y,Z line scans through the focus, with
phase corrections + steered to x = 10 mm, y = -10

本研究收集了数据以评估元素尺寸、元素位置、相对源压力变化以及电串扰对由555 kHz 32元素超声波阵列产生的压力场建模精度的影响。该换能器由32个直径为3毫米的单个平面圆形压电陶瓷元件（XDR107，Sonic Concepts，华盛顿州博塞尔）组装而成，这些元件以伪随机配置排列在三维打印的球形帽支架中，曲率半径为80毫米，孔径直径为70毫米。测量使用0.2毫米PVDF针形水听器（Precision Acoustics）在准稳态条件下（35周期脉冲）进行。所有测量均使用充满脱气、去离子水的自动化扫描水槽进行采集。换能器固定在xyz位置，水听器则安装于自动化xyz平台上，并具备手动倾斜和旋转调整功能。在焦点前区域进行了平面扫描，以表征在三种驱动条件下的源特性：所有元件以相同幅度和相位驱动、应用从几何焦点位置的水听器测量获得的相位校正，以及这些校正加上进一步几何计算的相位偏移，以将阵列焦点引导至x = 20毫米，y = -20毫米。此外，还获得了一系列通过焦点的线扫描，包括等幅未引导情况、焦点引导至x = -20毫米，y = 20毫米，以及8个进一步的引导焦点位置。总体而言，这项研究包含33个数据集，包含在1个文件中，论文中相应的图或表编号置于括号内。