Determination of online thin film buckling configuration by parametric optimization for flexible sensor application.

A mini basket type mapping catheter consists of thin film flexible sensors and is applied in the medical field to measure the electrocardiography (ECG) signals in order to localize and quantize the physiological condition/status of heart. The flexible nature of the thin film changes the configuration with respect to the contact boundary conditions when it contacts a target surface. Therefore, to accurately localize the flexible sensor, the thin film flexible sensor's configuration must be determined accurately in an on-line fashion. As a study of localizing the thin film flexible sensor, this study proposes an on-line thin film buckling configuration determination method using parametric optimization and interpolation technique. With the specific modulus of elasticity and dimensions of the thin film flexible sensor of the mapping catheter prototype, the buckling configuration with two point boundary condition under axial load can be calculated in desktop environment. The proposed calculation method is validated by mapping catheter sensor prototype test. The calculation/test results showed that the maximum overall length L, x[Formula: see text], and y[Formula: see text] value error between the calculation and experiment are approximately 0.16 mm, - 0.12 mm. - 0.10 mm in 50 ms calculation time. The calculation result of the proposed method is also compared with that of the numerical simulation by FEM, which has approximately 0.44 mm y[Formula: see text] value error compared with that of the experiment.

A Sarcopenia Detection System Using an RGB-D Camera and an Ultrasound Probe: Eye-in-Hand Approach.

Skeletal muscle mass deficiency and quality degradation constitute sarcopenia for elderly people. Sarcopenia can result in musculoskeletal damage and accompany various metabolic problems, which make early sarcopenia diagnosis important. Various modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), have been developed for screening sarcopenia. Recently, ultrasound scanning was suggested for screening sarcopenia because of its safety, usability, and cost effectiveness. However, there has been no standardized assessment methodology for screening sarcopenia with ultrasound scanning. Therefore, prior to this study, we developed a four-degrees-of-freedom (DOF) sarcopenia detection system using an RGB-D camera and an ultrasound probe to automatically scan the human thigh without operator dependency. However, due to the eye-to-hand approach with the RGB-D camera, the system has limited usability for clinical trials. Therefore, in this study we modified the system such that it became eye-in-hand by attaching the RGB-D camera to the upper part of the system with an enhanced arc fitting algorithm. The modified system and enhanced algorithm were verified by an in-vitro test with bean curd-gelatin phantom. The results showed that the thickness of bean curd in the gelatin phantom was maintained at approximately 12.7 ± 0.35 mm over the 71.5∘ scanning range with 2.49 ± 0.15 N radial force at various thickness measuring points.

Sarcopenia Detection System Using RGB-D Camera and Ultrasound Probe: System Development and Preclinical In-Vitro Test.

Sarcopenia is defined as muscle mass and strength loss with aging. As places, such as South Korea, Japan, and Europe have entered an aged society, sarcopenia is attracting global attention with elderly health. However, only few developed devices can quantify sarcopenia diagnosis modalities. Thus, the authors developed a sarcopenia detection system with 4 degrees of freedom to scan the human thigh with ultrasound probe and determine whether he/she has sarcopenia by inspecting the length of muscle thickness in the thigh by ultrasound image. To accurately measure the muscle thickness, the ultrasound probe attached to the sarcopenia detection system, must be moved angularly along the convex surface of the thigh with predefined pressure maintained. Therefore, the authors proposed an angular thigh scanning method for the aforementioned reason. The method first curve-fits the angular surface of the subject's thigh with piecewise arcs using D information from a fixed RGB-D camera. Then, it incorporates a Jacobian-based ultrasound probe moving method to move the ultrasound probe along the curve-fitted arc and maintains radial interface force between the probe and the surface by force feedback control. The proposed method was validated by in-vitro test with a human thigh mimicked ham-gelatin phantom. The result showed the ham tissue thickness was maintained within approximately 26.01 ± 1.0 mm during 82° scanning with a 2.5 N radial force setting and the radial force between probe and surface of the phantom was maintained within 2.50 ± 0.1 N.

Gain determination of feedback force for an ultrasound scanning robot using genetic algorithm.

PURPOSE: The remote medical diagnosis system (RMDS) is for providing medical diagnosis to the patients located in remote sites. To apply to RMDS and medical automation, many master-slave type ultrasound scanning robots are being developed and researched. One of the important research issue of the master-slave type ultrasound scanning robot is to determine the gains of the feedback force. Therefore, in this study, we suggest a gain determination method of feedback force for a master-slave type ultrasound thyroid scanning robot using a genetic algorithm. METHOD: A master-slave type ultrasound thyroid scanning robot (NCCMSU) was constructed, and the optimal y and z direction feedback force gains were calculated for NCCMSU with genetic algorithm. The Hunt-Crossley model is used to model the elastic behavior of the thyroid phantom and the thyroid scanning procedure is embedded in genetic algorithm by modeling the procedure mathematically. The genetic algorithm solves the average feedback force-overall procedure time optimization problem to seek optimal y, z direction feedback gains candidates. RESULTS: The rating results show that although there are some deviations among the subjective ratings, the feedback force with the determined gain setting is within the appropriate range. By analyzing the subjective rating test, the optimal y, z direction feedback force gains were determined. The optimal gains were verified by thyroid phantom scanning test and the scanned ultrasound image analysis. CONCLUSION: With the proposed method, the y, z direction optimal feedback force gains of the master-slave type ultrasound scanning robots can be determined. The proposed methods were verified by thyroid phantom scanning test.

Development of a control algorithm for the ultrasound scanning robot (NCCUSR) using ultrasound image and force feedback.

BACKGROUND: Clinicians who frequently perform ultrasound scanning procedures often suffer from musculoskeletal disorders, arthritis, and myalgias. To minimize their occurrence and to assist clinicians, ultrasound scanning robots have been developed worldwide. Although, to date, there is still no commercially available ultrasound scanning robot, many control methods have been suggested and researched. These control algorithms are either image based or force based. If the ultrasound scanning robot control algorithm was a combination of the two algorithms, it could benefit from the advantage of each one. However, there are no existing control methods for ultrasound scanning robots that combine force control and image analysis. Therefore, in this work, a control algorithm is developed for an ultrasound scanning robot using force feedback and ultrasound image analysis. METHODS: A manipulator-type ultrasound scanning robot named 'NCCUSR' is developed and a control algorithm for this robot is suggested and verified. First, conventional hybrid position-force control is implemented for the robot and the hybrid position-force control algorithm is combined with ultrasound image analysis to fully control the robot. The control method is verified using a thyroid phantom. RESULTS: It was found that the proposed algorithm can be applied to control the ultrasound scanning robot and experimental outcomes suggest that the images acquired using the proposed control method can yield a rating score that is equivalent to images acquired directly by the clinicians. CONCLUSIONS: The proposed control method can be applied to control the ultrasound scanning robot. However, more work must be completed to verify the proposed control method in order to become clinically feasible. Copyright © 2016 John Wiley & Sons, Ltd.

Impedance and admittance control for respiratory-motion compensation during robotic needle insertion - a preliminary test.

BACKGROUND: Many robotic needle-biopsy systems have been developed to enhance the accuracy of needle-biopsy intervention. These systems can reduce the intervention time and the radiation exposure of clinicians. However, respiratory-motion compensation is needed to ensure the accuracy and efficiency of needle biopsy intervention. METHODS: Human respiratory-motion data were acquired using three inertial measurement units (IMUs), and respiratory motion was simulated using the Stewart-Gough platform. Robotic needle intervention was performed using impedance and admittance control algorithms for respiratory-motion compensation using the Stewart-Gough platform and a gelatin phantom. RESULTS: The impedance and admittance control algorithms can be used to compensate for respiratory motion during robotic needle insertion. The admittance control algorithm exhibits better performance than the impedance control algorithm. CONCLUSIONS: The impedance and admittance control algorithms can be applied for respiratory-motion compensation during robotic needle insertion. However, further study is needed for them to become clinically feasible.

Clinical Application of Solid Model Based on Trabecular Tibia Bone CT Images Created by 3D Printer.

OBJECTIVES: The aim of this work is to use a 3D solid model to predict the mechanical loads of human bone fracture risk associated with bone disease conditions according to biomechanical engineering parameters. METHODS: We used special image processing tools for image segmentation and three-dimensional (3D) reconstruction to generate meshes, which are necessary for the production of a solid model with a 3D printer from computed tomography (CT) images of the human tibia's trabecular and cortical bones. We examined the defects of the mechanism for the tibia's trabecular bones. RESULTS: Image processing tools and segmentation techniques were used to analyze bone structures and produce a solid model with a 3D printer. CONCLUSIONS: These days, bio-imaging (CT and magnetic resonance imaging) devices are able to display and reconstruct 3D anatomical details, and diagnostics are becoming increasingly vital to the quality of patient treatment planning and clinical treatment. Furthermore, radiographic images are being used to study biomechanical systems with several aims, namely, to describe and simulate the mechanical behavior of certain anatomical systems, to analyze pathological bone conditions, to study tissues structure and properties, and to create a solid model using a 3D printer to support surgical planning and reduce experimental costs. These days, research using image processing tools and segmentation techniques to analyze bone structures to produce a solid model with a 3D printer is rapidly becoming very important.