There is growing evidence that spatial-peak temporal-peak (SPTP) ultrasound
intensity on the order of 100mW/cm2 delivered at frequencies below 100 kHz can
have beneficial therapeutic effects. However, conventional piezoelectric
transducer design using half-wavelength thickness disc is not
well suited for operation at these frequencies, hence an alternative transducer implementation is
proposed. More specifically, this work describes optimization of un-tethered,
low voltage, 20-100 kHz flexural transducers for biomedical ultrasonics
applications. The goal of this work was to design a fully wearable, low weight
(<100g), battery operated, piezoelectric ultrasound applicator providing
maximum output pressure amplitude at the minimum excitation voltage. The parameters
considered in optimization process will be reviewed and the results of the
acoustic output measurements will be presented along with the final
implementation of the transducer.
The prototype tested permitted operation at any frequency in the 20-100
kHz range, had integrated electronic driver and was powered using rechargeable
batteries. The maximum pressure amplitude generated was determined to be about
77kPa or 200mW/cm2 ISPTP. Being able to produce
this intensity level with merely 15-20V provides a fully wearable un-tethered
ultrasound device, attractive from both the patients and physicians'
perspective, as it potentially increases the patient compliance with
physician’s recommendations. Encouraging
results of small clinical wound healing study will also be presented.
Acknowledgements: This work was supported by the NIH
grant 5 R01 EB009670.
