Biomechanical modeling of the small intestine as required for the design and operation of a robotic endoscope

This paper discusses biomechanical issues that are related to the locomotion of a robotic endoscope in the human small intestine. The robot propels itself by pushing against the intestinal walls, much like a pipe crawler. However, the small intestine is not a rigid pipe; and locomotion in it is further complicated by the fact that the bowel is susceptible to damage. With the goal of engineering a safe and reliable machine, the biomechanical properties of the small bowel are studied and related to the mechanics of robotic endoscope locomotion through the small intestine

THz and mm-Wave Sensing of Corneal Tissue Water Content: Electromagnetic Modeling and Analysis.

Terahertz (THz) spectral properties of human cornea are explored as a function of central corneal thickness (CCT) and corneal water content, and the clinical utility of THz-based corneal water content sensing is discussed. Three candidate corneal tissue water content (CTWC) perturbations, based on corneal physiology, are investigated that affect the axial water distribution and total thickness. The THz frequency reflectivity properties of the three CTWC perturbations were simulated and explored with varying system center frequency and bandwidths (Q-factors). The modeling showed that at effective optical path lengths on the order of a wavelength the cornea presents a lossy etalon bordered by air at the anterior and the aqueous humor at the posterior. The simulated standing wave peak-to-valley ratio is pronounced at lower frequencies and its effect on acquired data can be modulated by adjusting the bandwidth of the sensing system. These observations are supported with experimental spectroscopic data. The results suggest that a priori knowledge of corneal thickness can be utilized for accurate assessments of corneal tissue water content. The physiologic variation of corneal thickness with respect to the wavelengths spanned by the THz band is extremely limited compared to all other structures in the body making CTWC sensing unique amongst all proposed applications of THz medical imaging

Detection of surgical margins in oral cavity cancer

Purpose of reviewThe quantity of tissue removed during an oncologic surgical procedure is not standardized and there are numerous reports of local recurrence despite histologically adequate resection margins. The oral cavity is one of the sites in the head and neck with high chances of recurrence following negative margins. To address this need, this article reviews the recent applications of Dynamic Optical Contrast Imaging (DOCI) towards both oral screening and the intraoperative evaluation of tumor margins in head and neck surgery.Recent findingsHuman ex-vivo and in-vivo trials suggest DOCI is well tolerated, low-cost, and sensitive for differentiating cancerous from normal tissues throughout the head and neck, in addition to the oral cavity. Ex-vivo imaging of OSCC specimens generated histologically verified image contrast. Furthermore, in-vivo intraoperative results demonstrate significant potential for image-guided detection and resection of oral cavity squamous cell carcinoma (OSCC).SummaryDOCI augments tissue contrast and may enable surgeons to clinically screen patients for oral cancer, make histologic evaluations in vivo with fewer unnecessary biopsies, delineate clinical margins for tumor resection, provide guidance in the choice of biopsy sites, and preserve healthy tissue to increase the postoperative functionality and quality of life of the patient