Evaluation of a robotic palpation sensor system for prostate cancer screening on silicone elastomers and prostate phantoms

Abstract

Prostate Cancer (PCa) is one of the most frequently diagnosed type of cancer in men. Cancerous regions in the prostate gland are stiffer compared to surrounding normal prostatic tissue. The digital rectal examination (DRE) which is performed manually by a medical examiner in order to assess the presence of hard lesions is a readily available primary clinical screening method for PCa, since the growth of tumors in the prostate alters the morphology and stiffness of the prostate. This method, however, is subjective, lacks repeatability, and the results depend on the skill and experience of the medical examiner. Alternative objective palpation modalities capable of obtaining quantitative spatial-temporal information about the mechanical properties variations of the prostate as a result of a pathological condition are required. In this study we investigated the use of a robotic palpation sensor system for PCa screening based on the tissue mechanical properties characterization. We evaluated the performance of the sensor system through indentation palpation tests on silicone elastomers and prostate phantoms with embedded hard inclusions which mimicked different PCa conditions. We compared the results obtained by the proposed sensor system with those obtained by using a commercial indentation machine. From the force-indentation depth quantitative information obtained at specific palpation points on the samples, the proposed sensor system was able to obtain a good estimation of the elastic modulus (E) and was capable of distinguishing stiff regions embedded with hard inclusions from soft regions based on these values, thus, presenting potential in palpation applications for PCa screening.

Keywords

• robotic palpation
• prostate cancer
• digital rectal examination
• elastic modulus
• indentation