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

We have developed a novel device suited for the in vivo assessment of soft tissue quality, in this case applicable to the prostate. Studies have shown relationships between the histology of prostate tissue and elements of its complex modulus. The in situ assessment of prostate tissue quality, using digital rectal examination (DRE), is one of the first steps taken in diagnosing prostate cancer. The first aim is to instrument this procedure. Steps have also been taken to determine if our device has applications in dissections and surgical procedures, to help identify different parts of the anatomy through tissue feel and stiffness.

Previous work has demonstrated tissue assessment using a hydraulic palpation device 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. This can be expressed as an amplitude ratio (|E*|) and phase difference (tan δ). That device cannot easily be applied in vivo, so we have developed a scalable, micro-engineered device, designed for such purposes. Using the same principles, the design of the device is such that it can be incorporated onto the end of a clinician’s finger, under a standard surgical glove where it can be actuated pneumatically at various frequencies. Utilizing a vibrating membrane with an embedded strain gauge, a force is transmitted through the tissue sample and the response is measured. This presentation will present the work carried out to date and the data which has been collected from the device. It will discuss the correlations found between tissue morphology and its mechanical characteristics, which allow us to distinguish between healthy and diseased tissue. It will also look at how detecting changes in tissue types can be used to identify different parts of the anatomy and how this can be utilized during surgery.