Design and Development of a Novel Soft and Inflatable Tactile Sensing Balloon for Early Diagnosis of Colorectal Cancer Polyps.

In this paper, with the goal of addressing the high early-detection miss rate of colorectal cancer (CRC) polyps during a colonoscopy procedure, we propose the design and fabrication of a unique inflatable vision-based tactile sensing balloon (VTSB). The proposed soft VTSB can readily be integrated with the existing colonoscopes and provide a radiation-free, safe, and high-resolution textural mapping and morphology characterization of CRC polyps. The performance of the proposed VTSB has been thoroughly characterized and evaluated on four different types of additively manufactured CRC polyp phantoms with three different stiffness levels. Additionally, we integrated the VTSB with a colonoscope and successfully performed a simulated colonoscopic procedure inside a tube with a few CRC polyp phantoms attached to its internal surface.

A Reliable and Sensitive Framework for Simultaneous Type and Stage Detection of Colorectal Cancer Polyps.

With the goal of enhancing the early diagnosis of colorectal cancer (CRC) polyps and reducing the risk of mortality in cancer patients, in this article, we present a unique diagnosis framework including a Vision-based Surface Tactile Sensor (VS-TS) and complementary Artificial Intelligence algorithms. Leveraging the morphological characteristics (i.e., shape and texture) and stiffness features of the CRC polyps, the proposed framework is able to reliably and sensitively identify their type and stage. To thoroughly characterize and identify the required VS-TS sensitivity for reliable identification of polyps, we first fabricated three different VS-TSs and qualitatively evaluated their performances on 48 different types of polyp phantoms fabricated based on four different types of realistic CRC polyps and three different materials. Next, to quantitatively compare the performance and sensitivity of the fabricated VS-TSs, we used Support Vector Machine (SVM) algorithm and employed various statistical metrics (i.e., accuracy, reliability, and sensitivity). Next, using the most sensitive VS-TS, we classified the type of tumors using the SVM algorithm and applied the t-Distributed Stochastic Neighbor Embedding algorithm to successfully identify the stiffness of classified polyp phantoms solely based on the output images of the VS-TS sensor. Results demonstrated that an SVM algorithm applied on the image outputs of a VS-TS with a Shore hardness of 00-40 scale is able to classify all types of polyps with > 90% accuracy, sensitivity, and reliability. We also repeated experiments on samples of ex-vivo lamb tripe tissues and successfully verified the high sensitivity and reliability of the proposed framework (i.e., > 94%).

VnStylus: A Haptic Stylus With Variable Tip Compliance.

Variable stiffness tools have been shown to be advantageous for ensuring safety and improving stability, dynamic performance and energy efficiency of interaction tasks. In this article, we present the design, mathematical modeling, implementation, characterization and user evaluations of VnStylus, a stylus with hardware-based tip compliance modulation. The stiffness modulation of the stylus tip is achieved through transverse stiffness variations of axially loaded beams. This approach of mechanically-controlled stiffness variation is advantageous for a variable stiffness stylus, as it can be implemented using a fully compliant mechanism that alleviates the problem of friction forces dominating under miniaturization and allows for high fidelity stiffness display even for very low stiffness values. Thanks to its hardware-based impedance modulation, the device does not suffer from the bandwidth and the stable impedance rendering limitations of software-based impedance control strategies. Featuring a manual adjustment mechanism, the device does not necessitate actuators, sensor or electronics; hence, is lightweight, low cost, and robust. Experimental characterizations verify the large range of stiffness modulation that can be achieved and the accuracy of the equivalent stiffness model of the system. Human subject experiments provide evidence of the efficacy of the modulated stylus stiffness on human performance during several common interactions with styli.