\Resin-Based Lens Repair and Characterization of a Custom 8-Element Histotripsy Transducer\ data files

Custom ultrasound transducer arrays fabricated by stereolithography enable low\u2011cost prototyping of complex geometries, but the long\u2011term durability is limited by resin aging, fragility and lens cracking. This work presents a quantitative demonstration of a resin\u2011based repair protocol for a custom 8\u2011element focused ultrasound array with lens fracture damage after being dropped. The electrical impedance of the array\u2019s piezoelectric elements did not change significantly before and after damage, supporting a repair protocol focused on the acoustic lens alone. A diluted Accura\u00ae 60 resin mixture was injected into surface cracks, cured under ultraviolet light, and post\u2011cured at 60 \u00b0C to achieve watertight sealing. Acoustic output was evaluated by absolute voltage\u2013pressure calibration, needle hydrophone\u2011based beam profiling, and element\u2011wise impedance analysis. The repaired array generated peak compressional and rarefactional pressures within 1.5 dB (16%) of original calibration, with beamwidths (1.1 mm lateral, 7.3 mm axial) modestly broadened. Among the three conditions (before damage, after damage, and after repair), impedance was not significantly different. Taken together, these results demonstrate that resin injection and subsequent curing can restore functional acoustic output and preserve sufficient beam focus for some therapeutic applications. Our results with Accura\u00ae 60 suggest that the approach of solvent dilution and ultraviolet curing can provide a potential cost\u2011effective framework for repairing stereolithography\u2011printed ultrasound devices. This study highlights both the utility and limitations of resin\u2011based repair, underscoring the need for systematic protocols to enable broader adoption of additive manufacturing in therapeutic ultrasound research.

采用立体光刻（Stereolithography）制备的定制超声换能器阵列可实现复杂结构的低成本原型制备，但长期耐用性受树脂老化、材料脆性及声透镜开裂的制约。本研究针对一款因跌落导致声透镜断裂损坏的定制8阵元聚焦超声阵列，展示了一种基于树脂的修复方案的量化验证结果。该阵列压电元件的电学阻抗在损坏前后无显著差异，这为仅针对声透镜的修复方案提供了支撑依据。研究人员将稀释后的Accura® 60树脂混合物注入表面裂纹，经紫外光固化后再于60℃下进行后固化，最终实现水密密封。通过绝对电压-压力校准、针式水听器波束轮廓分析以及逐元阻抗分析，对该阵列修复后的声学输出性能进行了评估。修复后的阵列所产生的峰值压缩压强与稀疏压强，相较于原始校准值的偏差均在1.5 dB（16%）以内；波束宽度（横向1.1 mm、轴向7.3 mm）仅出现小幅展宽。在损坏前、损坏后及修复后三种状态下，阵列压电元件的电学阻抗均无显著差异。综合上述结果可知，树脂注入及后续固化工艺可恢复有效的声学输出性能，并保留足够的波束聚焦能力，可满足部分治疗超声应用的需求。我们基于Accura® 60树脂的实验结果表明，溶剂稀释结合紫外固化的方案，可为立体光刻打印超声器件的修复提供一种兼具成本效益的潜在可行路径。本研究既阐明了基于树脂的修复方案的实用性与局限性，也强调了建立标准化修复流程的必要性，以推动增材制造在治疗超声研究中的更广泛应用。