Development of a Vibrating Device Using a Linear Resonant Actuator for Fine-Needle Aspiration Cytology

  • Purpose: Fine-needle aspiration cytology (FNAC) is a valuable diagnostic technique. However, the procedure involves back-and-forth motions of a needle within a mass, which can lead to unexpected complications. We have developed a device and sampling techniques that use vibration and rotation instead of back-and-forth motions in 2009. The device consists of a vibrating motor fixed to the stopper of a 5 ml syringe with its piston. The motor is an eccentric rotating mass (ERM), 12 mm in diameter, 3.4 mm thick and 220 Hz in frequency. The vibrating device caused no serious complication until now. Inadequacy rates of FNAC was improved to 6.1% by the vibrating device from 18.2% by the conventional technique. On the other hand, there is a linear resonant actuator (LRA) as a vibrating motor instead of ERM. We can control an amplitude, a phase and a frequency of LRA, which can lead to further improvement of the vibrating device.

    Methods: We adopted a LRA 11 by 14 mm in size, 2.6 mm thick and 150 Hz in resonant frequency to the vibrating device. We optimized the frequency of LRA by visualization of the needle motion using a high-speed camera and sampling on resected specimens.

    Results: The needle motion had only a horizontal component with the direction of vibration. The amounts of cellular material were sufficiently diagnostic.

    Conclusions: A device using LRA is expected to have no less efficacy than a device using ERM. We are going to evaluate inadequacy rates of FNAC using the LRA device.

 

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