Thermal Modelling of Fibre-Optic Laser Generated Ultrasound Transmitters - Data.zip

Optical generation of ultrasound has broad applicability in diagnostic and therapeutic clinical applications. With fibre-optic ultrasound transmitters, ultrasound waves are generated photoacoustically by laser pulses incident on an optically-absorbing coating at the distal end of an optical fibre. Energy from the laser pulses that is not converted to ultrasound raises the temperature of the transmitter coating and surrounding medium. Limiting the maximum temperature is important for tissue safety and the integrity of the transmitter. In this study, we used a finite element thermal model of a fibre-optic ultrasound transmitter to study the influence of three parameters on the temperature rises in the transmitter and the surrounding medium: the laser pulse energy, the laser pulse repetition frequency, and the coating absorption coefficient. To evaluate the validity of the model, the simulation results were compared with thermal imaging experiments of a carbon-polydimethylsiloxane composite-based fibre-optic ultrasound transmitter. Of the studied parameters, the pulse repetition frequency (PRF) has the greatest impact on the temperature rise in the surrounding medium, with a six-fold rise in temperature change resulting from an increase in PRF from 100 Hz to 1 kHz. Our findings have direct applicability to optimising the performance of fibre optic transmitters.

光学超声的产生在诊断和治疗临床应用中具有广泛的应用前景。利用光纤超声发射器，通过激光脉冲照射光纤远端的光吸收涂层，可实现光电声学方式产生超声波。未被转化为超声波的激光脉冲能量将提升发射器涂层及其周围介质的温度。限制最大温度对于确保组织安全及发射器的完整性至关重要。在本研究中，我们构建了一个光纤超声发射器的有限元热模型，以研究激光脉冲能量、激光脉冲重复频率和涂层吸收系数三个参数对发射器及其周围介质温度上升的影响。为验证模型的有效性，我们将模拟结果与基于碳聚二甲基硅氧烷复合材料的纤维光学超声发射器的热成像实验结果进行了比较。在所研究的参数中，脉冲重复频率（PRF）对周围介质温度上升的影响最为显著，当PRF从100 Hz增加到1 kHz时，温度变化增加了六倍。我们的研究结果对于优化光纤发射器的性能具有直接的指导意义。