A scalable actuator for the dynamic palpation of soft tissue for use in the assessment of prostate tissue quality

We will report on a novel device for in vivo assessment of prostate tissue quality. Studies have shown a relationship between the histology of prostate tissue and elements of its complex modulus [1]. One of the first steps for in vivo assessment of prostate cancer is digital rectal examination (DRE), and our first aim is to instrument this procedure.

Previous work demonstrated ex vivo assessment using hydraulic palpation in which a controlled sinusoidal strain is applied over a range of actuation frequencies and the resulting force is used to obtain the dynamic elastic modulus, expressed as an amplitude ratio (|E*|) and phase difference (tan δ). We have developed a scalable, micro-engineered device that can be applied in vivo using the same principles, but utilizing a vibrating silicone membrane with embedded strain gauges to apply the displacement and measure the force.

Continuing on from our previous work we have calibrated our probe and carried out in vivo testing along with comparison MRI scans and ex vivo measurements. We will demonstrate the findings from these tests, identifying the correlations seen with the histology of the tissue. Miniaturisation of the device has been carried out using the current technology. We will examine the fabrication and results from the initial testing with this device, as we prepare for transurethral patient testing. In examining ways to make our measurements more sensitive we have also prototyped a graphene printed strain gauge to be incorporated into our probes. An insight into the technology and fabrication behind this will also be examined.

REFERENCES

1. Phipps S, et al. Measurement of tissue mechanical characteristics to distinguish between benign and malignant prostatic disease. Urology 2005;66(2):447-5