Kenta Kuwana

• Professor (Assistant) at Tokyo Denki University

In this study, we evaluated the suction forces in the directions vertical and parallel to the contact face focusing on the diameter of the single suction cup of micro suction cup array. The suction force was measured by varying the pressing force during the attaching process of the micro suction cup arrays to the object. Three types of the micro su...

In this study, we proposed a thickness estimation method of tumor using a grasping forceps with sensors and evaluated the method by estimating the thickness of tumor models located in tissue models. Though palpation is an important technique for distinguishing a tumor, the palpation during thoracoscopic surgery is difficult because of the lack of t...

In this paper, we measured the relationship between the grasping position of the tissue model including a tumor model and the compression and shear forces detected by a grasping forceps with sensors during grasping. We prepared 3 types of tissue model made by gelatin. An acrylic ball as a tumor model was embedded in the tissue model varying the dep...

In this paper, we report a measurement method of viscoelastic properties of the grasped objects using a grasping forceps with sensors. Stiffness is one of the important information to distinguish the cancerous tissue from normal tissues because the mechanical properties of cancerous tissue change according to the grade of cancer. However, in laparo...

We measured the triaxial forces applied to the grasped object during the staple operation of a surgical stapler by a MEMS (Micro Electro Mechanical System) triaxial tactile sensor (Touchence Inc., FSI-020119P) to develop the criteria for the accurate automated suturing by surgical staplers. The compression force was 43.0 ± 0.1 N at the 5 mm from th...

In this work, we measured the bending moment using a grasping forceps with sensors. Grasping operations during the endoscopic surgery apply forces and moments to the grasped object. The forces and moments cause damage to the grasped object. Therefore, measurement of the forces and moments is necessary to prevent the damage by the over application....

Fetus sacrococcygeal teratoma is a fatal disease which makes blood flow abnormal. Popular approach for this treatment is to cut the teratoma off, nonetheless it is high-invasive with risks. So the use of HIFU(High Intensity focused ultrasound) is now attracting attention because of its capability of burning vessels to stop blood flow without openin...

This paper reports the grasping forceps with two triaxial MEMS (Micro Electro Mechanical Systems) tactile sensors on the both of the tips of a grasping forceps. In laparoscopic surgery, lack of tactile sense is one of the problems. The lack of the sense induces the possibility to apply excess forces on the grasped organs. Thus, we attached two tria...

This paper reports on a grasping forceps with a triaxial Micro Electro Mechanical Systems (MEMS) tactile sensor on a tip. The laparoscopic surgery is minimally invasive because the incisions are smaller than the open surgery. This results in fast recovery. However, it is a problem in the laparoscopic surgery to damage an organ by localized stress g...

We proposed a thin piezoelectric cantilever to measure an airflow velocity change. An airflow sensor using a PZT cantilever and a flow channel was fabricated. We measured the relationship between the airflow velocity change and the piezoelectric voltage of the cantilever. The dimensions of the sensor and the cantilever are 25 mm × 20 mm × 20 mm and...

Power management is a fundamental issue in wireless sensor networks. In this paper, a piezoelectric flow sensor is proposed for use as a wake-up switch in a wireless sensor node to reduce power consumption. A cantilever with a Pb (Zr, Ti) O3 (PZT) thin film detects airflow changes surrounding the wireless sensor node. A prototype of the flow sensor...

This paper describes a parallel piezoresistive cantilever that is composed of a force-sensing cantilever in addition to a reference cantilever for photoresponse compensation. Piezoresistive cantilevers have been applied in many cellular mechanical measurement studies because of their high sensitivity, high time resolution and ease of handling. Howe...

Background: During endoscopic surgical procedures, surgeons must manipulate an endoscope inside the body cavity to observe a surgical area while estimating the distance between that area and the surgical instruments by reference to a monitor on which the movement and size of the surgical instruments are displayed in 2-D endoscopic images. Therefor...

We have developed a new generation device called rigid-flexible outer sheath with multi-piercing surgery (MPS) to solve the issues of tissue closure, triangulation, and platform stability in natural orifice transluminal endoscopic surgery (NOTES), and the problems of restricted visual field, organ damage, and removing a resected organ from body in...

Magnetic Resonance Imaging (MRI) is widely used not only for diagnosis but also for surgical navigation, etc. Sursgeons and surgery-support systems can conduct surgeries less invasively because they derive accurate positional relationships between surgical instruments and anatomical regions of interest from preoperative or intraoperative MRI images...

Chromosome segregation machinery is controlled by mechanochemical regulation. Tension in a mitotic spindle, which is balanced by molecular motors and polymerization-depolymerization dynamics of microtubules, is thought to be essential for determining the timing of chromosome segregation after the establishment of the kinetochore-microtubule attachm...

Power management technology is a fundamental issue in wireless sensor network. In this paper, we propose a concept of a piezoelectric flow sensor for a wake-up switch of a wireless sensor node to reduce the power consumption. The sensor detects air flow change surrounding the wireless sensor node by using a cantilever with Pb(Zr, Ti)O3 (PZT) thin f...

Purpose In endoscopic surgery, surgeons must manipulate an endoscope inside the body cavity to observe a large field-of-view while estimating the distance between surgical instruments and the affected area by reference to the size or motion of the surgical instruments in 2-D endoscopic images on a monitor. Therefore, there is a risk of the endoscop...

We have developed endoscopic laser irradiation devices for minimal invasive laser therapy of twin-to-twin transfusion syndrome, which is circulatory derangement between twin fetuses. In this paper we propose three devices, 1) a miniature bending laser manipulator, 2) a composite-type optical fiberscope to irradiate center point of the fiberscopic i...

To address the access and stability problems in endoscopic surgery, we developed a device called rigid–flexible outer sheath. This sheath can be switched between flexible and rigid modes by a novel pneumatic shapelocking mechanism, and it has a double curvature structure that enables it to flex in four directions at the distal end and three directi...

Fetal surgery sometimes requires multiple field-of-views (FOVs). The authors have developed an FOV extended endoscope for simultaneously observing front and lateral view with single lens system. A polarizing beam splitter (PBS) mounted at its distal end guides the rays from the two FOVs to relay lenses in orthogonal linear polarizations, and the ot...

We developed clipping device that could carry out edge-to-edge repair through endoscopic observation of the intracardiac valves, without using a heart-lung machine. One is a clear liquid-flushing endoscope which equipped coaxial round jet nozzle to observe φ8-mm area, called “wide view coaxial nozzle”. The other one is a clipping mechanism to carry...

Three-dimensional (3-D) displays have been receiving attention since they are more realistic and intuitive than two dimensional (2-D) displays. In this study, a rendering method to extract important features and enhance them for creating Integral Videography (IV) for medical use was studied and implemented. The resolution of IV mainly depends on th...

This paper reports a miniaturized endoscope that transmits a high-power infrared laser beam to arbitrary points in the endoscopic view for the treatment of twin-to-twin transfusion syndrome. The miniaturized endoscope has an external diameter of 3.5 mm expect for illumination and also improved on the laser transmission efficiency by using a GRIN ro...

We present an augmented reality system for oral and maxillofacial surgery in this paper. Instead of being displayed on a separated screen, three-dimensional (3D) virtual presentations of osseous structures and soft tissues are projected onto the patient's body, providing surgeons with exact knowledge of depth information of high risk tissues inside...

Single port access (SPA) surgery is a laparoscopic procedure using only one transumbilical-placed port. Natural orifice transluminal endoscopic surgery (NOTES) offers the possibility of surgery without visible scars. To address the access and stability problems in SPA and NOTES, we developed a device called rigid-flexible outer sheath. This sheath...

Integral Photography (IP) [Hongen Liao 2011] is a visualization technique that produce true three-dimensional images in the real space that can be viewed without supplementary glasses. Using a micro lens array, different aspects of the object can be viewed from different directions, giving observers a sense of depth. Utilizing IP images into augmen...

This paper reports on a photodiode (PD) with micro texture for miniaturizing particle sensors. We proposed an optical system for a small particle-sensor without focus lenses. The system requires a PD which is high sensitive at large angle of incidence. The micro texture was fabricated on a surface of the PD to achieve the required property. The mic...

This paper describes a Si nano-pillars array for measuring traction forces of one singular filopodium (100-300 nm in diameter). We fabricated the Si nano-pillar which was 110 nm in diameter and 1.5 µm in length. Fibroblasts were cultured on the Si nano-pillar array. The filopodium of fibroblast adhered to pillar and dragged it. We calculated the tr...

In this paper, we propose a sensor for measuring the three-dimensional (3D) velocity vector of airflows. The sensor, which was a 10 mm spherical figure, had a laminated structure with three channels fabricated inside. The components of the airflow velocity vector were measured respectively by three piezo-resistive cantilevers fabricated in each of...

Fetal surgery aims to stop progression of congenital disease and to protect fetus from disorders by therapy before birth. Although endoscopic approach is minimally invasive, it has some difficulties. In order to solve the problems, we develop a laser treatment system for fetal surgery. Endoscope steers a laser beam transmitted coaxially to a target...

This paper presents the design, fabrication, and the characterization of a photo-response compensated piezoresistive cantilever. The application field of the cantilever is to measure cellular mechanical properties under fluorescence microscopy. Photo-response which is caused by an excitation light of a fluorescence microscope interferes with measur...

Accurate chromosome segregation during meiosis depends on the assembly of a microtubule-based spindle of proper shape and size. Current models for spindle-size control focus on reaction diffusion-based chemical regulation and balance in activities of motor proteins. Although several molecular perturbations have been used to test these models, contr...

In this study, we report on an implantable wireless device for measuring the oxygen saturation and the heartbeat. The device consists of a sensor part, a data transfer part, and a power supply part. We fabricated the test device for the sensor part. We measured the oxygen saturation and the heartbeat from an index finger. The heartbeat and the oxyg...

This paper reports on a micro planar coil as a receiver for a high resolution MRI (Magnetic Resonance Imaging). In this study, a micro planar coil of 10 mm in diameter was fabricated. The MRI signal receiving device was made by attaching the micro coils to the tip of acrylic pipes. The signal to noise ratio of MR image taken by the micro planar coi...

In this study, we have developed an implantable telemetry capsule for monitoring heartbeat. The capsule has three main functions, monitoring vital signs, transmitting the vital signs, and receiving energy for driving the capsule without wires. We used two wavelengths of LEDs and a photodiode sensitive to the two wavelengths for heartbeat sensor. Th...

This paper reports on a standing micro coil as a receiver for a high resolution MRI (Magnetic Resonance Imaging). A standing micro coil was fabricated by post release folding process. Our coil standing in free space had uniform sensitive area and high sensitivity. We demonstrated that a 12×12×1000 ¿m3 resolution image of pine needles was taken b...