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Heart and cerebrovascular diseases such as arteriosclerosis and myocardial ischemia dysfunction are currently among the main causes of death in developed countries. Recently, wave intensity (WI), which is an index used to obtain the force of cardiac contraction, has been investigated as a method for early-stage diagnosis of the above-mentioned diseases. Nevertheless, experimental tests have proven that the manual measurements of WI by means of commercial ultrasonic diagnostic systems require too much time and can be affected by the operator's skills. For this purpose, the introduction of robotic-assisted technology has advantages in terms of repetitiveness and accuracy of the measurement procedure. Therefore, at Waseda University, the development of a carotid blood flow measurement system has been proposed to support doctors while using ultrasound diagnostic equipment to measure the WI. This robotic system is composed of a serial robot with a wrist having a six-degree-of-freedom (6-DOF) parallel mechanism. The main focus is to obtain a suitable workspace performance of the 6-DOF parallel mechanism wrist. In this paper, a workspace analysis is carried out on a wrist prototype built for the Waseda-Tokyo Women's Medical Aloka Blood Flow Measurement System No.1 Refined (WTA-1R). Then, mechanical design enhancements are proposed and validated to provide a suitable workspace performance both as reachable workspace and dexterity, and a refined prototype WTA-1RII has been built.

The emerging field of medical robotics is aimed at introducing intelligent tools. More recently, thanks to the innovations in robot technology (RT), advanced medical training systems have been introduced to improve the skills of trainees. The principal challenges of developing efficient medical training systems is that they must simulate real-world conditions of the task, provide objective assessments of training progress, and provide useful feedback to trainees. So far, many medical training systems have been developed; however, those training system do not fulfill the three conditions of the Active Training system. For the proof of concept of an effective Active Training system, we proposed WKA-4 (Waseda Kyotokagaku Airway No.4) which satisfies all of the requirements of the Active Training system. In this paper, we present the hardware configuration of the WKA-4 briefly, which has 11 embedded actuators and 44 embedded sensors, and simulates real-world condition of the task. In addition, in order to verify the usefulness of feedback of the WKA-4 for medical training, a set of the experiments were carried out to a doctor group and two novice groups. One novice group is provided by the feedback of the embedded sensors of the WKA-4 while the other novice group is not. From the comparisons of the results of the experiments, we verify the effectiveness of our proposed Active Training system.

One of the important tasks required for sonographers is an accurate positioning of ultrasound probe. Especially, the measurement of the diameter of the blood vessel is affected by the positioning error of the probe. For this purpose, we have been developing a robot system for the medical ultrasound diagnosis, which composed of a 6-DOFs probe manipulator and supporting arm. In this paper, we present an implementation of fully automated positioning algorithm of the ultrasound probe on the carotid artery, by means of image feedback. A probe holding robot firstly detects the patient skin, then scans and detects the longitudinal section of the carotid artery, guide the probe towards the position where the tissue layers of the artery walls are most clearly observed. Furthermore, a new method of the visual servoing for tracking the out-of-plane motion for the medical ultrasound is presented. Automated positioning algorithm is tested in eleven volunteers and the results show that the system successfully completed the task in 91% of the trials. Visual servoing algorithm is also tested and the experimental results show its effectiveness.