I Sakuma

National University of Singapore, Singapore, Singapore

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Publications (63)59.71 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Conventional surgical navigation requires for surgeons to move their sight and conscious off the surgical field when checking surgical tools positions shown on the display panel. Since that takes high risks of surgical exposure possibilities to the patients body, we propose a novel method for guiding surgical tool position and orientation directly in the surgical field by laserbeam. In our navigation procedure, two cross-sectional planar laser-beams are emitted from the two laser devices attached onto both sides of an optical localizer, and show surgical tools entry position on the patients body surface and its orientation on the side face of the surgical tool. In the experiments, our method gave the surgeons precise and accurate surgical tool adjusting and showed the feasibility to apply to both of open and percutaneous surgeries.
    IEEE transactions on bio-medical engineering 06/2012; · 2.15 Impact Factor
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    ABSTRACT: We have designed and developed a mobile PET probe using a 16ch CdTe detector. A PET endoscope system is constructed with the mobile probe, 144-channel LuAG APD PET detector and an optical position tracking system for the validation study of multi-modal system. The image is successfully reconstructed by integrating the position information and timing information.
    Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2012 IEEE; 01/2012
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    ABSTRACT: This study presents formulations of the velocity and force equations for a class of hybrid cable-driven manipulators constrained with serial linkage. Combining lightweight cables with linkages makes these manipulators lighter and more compact compared to all-cable-driven and all-rigid-link manipulators. Redundant actuation is required to keep the cables taut. The paper discusses two configurations: a) redundant actuators mounted on the passive joints of the serial linkage; and b) manipulators with redundant cables. To preserve generality, the analysis was based on three jacobian matrices that correspond to the serial linkage's active and passive joints as well as the driving cables. The paper presents two examples of configurations (a) and (b) where cable layouts were optimized utilizing techniques reported in earlier work of the authors. The examples include a 5-DOF and a spherical hybrid cable-driven manipulators with their workspace analysis.
    Mechatronics and Automation (ICMA), 2012 International Conference on; 01/2012
  • Photodiagnosis and Photodynamic Therapy - PHOTODIAGNOSIS PHOTODYN THER. 01/2011; 8(2):162-163.
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    ABSTRACT: A 3-D augmented reality navigation system using autostereoscopic images was developed for MRI-guided surgery. The 3-D images are created by employing an animated autostereoscopic image, integral videography (IV), which provides geometrically accurate 3-D spatial images and reproduces motion parallax without using any supplementary eyeglasses or tracking devices. The spatially projected 3-D images are superimposed onto the surgical area and viewed via a half-silvered mirror. A fast and accurate spatial image registration method was developed for intraoperative i.v. image-guided therapy. Preliminary experiments showed that the total system error in patient-to-image registration was 0.90 +/- 0.21 mm, and the procedure time for guiding a needle toward a target was shortened by 75%. An animal experiment was also conducted to evaluate the performance of the system. The feasibility studies showed that augmented reality of the image overlay system could increase the surgical instrument placement accuracy and reduce the procedure time as a result of intuitive 3-D viewing.
    IEEE transactions on bio-medical engineering 02/2010; 57(6):1476-86. · 2.15 Impact Factor
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    ABSTRACT: Fetal surgery is receiving considerable attention. However, surgeons must have great skill to perform this surgery. For assisting with the operation, the three-dimensional (3D) endoscope is very useful because it allows the surgeon depth perception. However, the diameter of existing 3D endoscopes is approximately 10 mm. Therefore, the authors have developed a high-resolution, thin, 3D endoscope for use in fetal surgery. The authors' system uses two 1/10-in. micro charge-coupled device (CCD) cameras at the tip of the endoscope and achieves a diameter of 5.4 mm. The endoscope's angle of convergence is 2.6 masculine, which very closely approximates the angle of convergence for humans. Thus, the surgeon experiences little visual fatigue. The view angle is 87 masculine. The authors compared image quality and depth perception between their system and conventional 3D and 2D endoscopes. Theoretical investigation of image quality allowed the surgeon to distinguish a line 0.2 to 0.25 mm wide. Furthermore, the depth perception with the thin 3D endoscope was almost the same as with an 11-mm normal 3D endoscope. In addition, with the 3D endoscope, a higher percentage of questions were answered correctly in the depth perception evaluation experiment in a water environment than with the 2D instrument. According to these experiments, the thin 3D endoscope has a sufficiently high image quality and depth perception even in a water environment.
    Surgical Endoscopy 04/2009; 23(11):2450-3. · 3.43 Impact Factor
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    ABSTRACT: Finger Braille is one of tactual communication media of deafblind people. Deafblind people who are skilled in Finger Braille can catch up with speech conversation and express various emotions. Because there are small non-disabled people who are skilled in Finger Braille, deafblind people communicate only with interpreters. Objective of this study is development of a Finger Braille supporting device which assists not only verbal communication but also non-verbal (emotional) communication between deafblind people and non-disabled people who are not skilled in Finger Braille. In this paper, to develop emotion recognition system, we analyzed features of emotional expression (Neutral, Joy, Sadness and Anger) and derived an algorithm of emotion recognition using accelerometers worn by receiver. According to the results of discriminant analysis, it was considered that emotion recognition using the discriminant functions by standardized data and the average of posterior probabilities in a sentence was possible and independent of sentences.
    Intelligent Information Hiding and Multimedia Signal Processing, 2008. IIHMSP '08 International Conference on; 09/2008
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    ABSTRACT: Finger Braille is one of tactual communication media of deafblind people. In one-handed finger Braille, a sender dots the left part of Braille code on the DIP joints of index, middle and ring fingers of a receiver, and then the sender dots the right part of Braille code on the PIP joints of them. Then the receiver recognizes the Braille code. Deafblind people who are skilled in Finger Braille can catch up with speech conversation and express various emotions. Because there are small non-disabled people who are skilled in Finger Braille, deafblind people communicate only with interpreters. In this paper, we developed a finger Braille recognition system. And evaluation experiments of recognition of monosyllables and sentences were carried out. As the results of the evaluation experiment of recognition of monosyllables, the accuracy of recognition of dotted fingers was 92.9% and the recognition system was independent of dotted strength, dotted position and receiver. The accuracy of recognition of dotted positions was 81.9% and the recognition system could recognize dotted positions if the receiver's hand shaped a natural longitudinal arch on the desk. As the results of the evaluation experiment of recognition of sentences, the accuracy of recognition of dotted fingers by dotting was 89.7% and the accuracy of recognition of dotted positions by dotting was 92.3%. Therefore the recognition system could recognize the sentences accurately when the interpreter dotted clearly. And the receiver should re-set his/her hand on the desk when he/she noticed cut-down of accuracy of recognition.
    Mechatronics and Automation, 2008. ICMA 2008. IEEE International Conference on; 09/2008
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    ABSTRACT: We have developed a surgical robotic system for femoral fracture reduction employing indirect traction. Indirect traction in fracture reduction is a generally used surgical method for preventing complications such as bone splits caused by high stress on bones. For traction, a patient's foot is gripped by a jig and pulled to the distal side. Indirect traction has the advantage of distributing bone stress by utilizing a strong traction force; however, this procedure does not accurately control the proper positioning of fractured fragments when a surgical robot is used. The human leg has knee and an ankle joints, and thus robotic motion presents problems in not being able to directly propagate reduction motion to a fractured femoral fragment, rendering control of bone position difficult. We propose a control method for fracture reduction robots using external force/torque measurements of the human leg to achieve precise fracture reduction. Results showed that the proposed method reduced repositioning error from 6.8 mm and 15.9 degrees to 0.7 mm and 5.3 degrees, respectively.
    Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 02/2008; 2008:3265-8.
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    ABSTRACT: Radiofrequency Ablation (RFA) assisted liver resection results in lesser blood loss during liver resections. It involves a time consuming and error prone process of alternating coagulation and cutting until the line of transaction is completed to finally divide the liver. We proposed a new robotic mechanism to automate the ablation and division process. The robotic device comprises a 2-link manipulator, an x-y translator, a flexi-arm as well as a liver ablation and division device. The process of precise linear motion ablation and cutting has been integrated with the guidance of a robotic mechanism to uniformly coagulate and slit areas of the parenchymal. A prototype of the robotic device has been evaluated on its ability to uniformly target a large region.
    Medical Imaging and Augmented Reality, 4th International Workshop, MIAR 2008, Tokyo, Japan, August 1-2, 2008, Proceedings; 01/2008
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    ABSTRACT: Blood loss is a concern in the liver resections. In line with the wide implementation of ablation process, bleeding during liver resections can be minimized. However, the division process has to be accurately monitored to provide efficient liver resection in terms of time and safety. The modeling of liver tissue and division tool interaction along with the deformation of the liver tissue is studied in this research. As liver tissue is made of complex viscoelastic material, we determined that it could be modeled using standard viscoelastic model based on biomechanics experiment on fresh porcine livers. This result is further extended to incorporate a modeled division tool. Simulation of the modeled interaction is discussed. A state control feedback system which can help monitor the combined ablation and division process is also proposed.
    01/2008;
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    ABSTRACT: ObjectTo investigate the usefulness of a newly developed magnetic resonance (MR) image-guided surgical robotic system for minimally invasive laparoscopic surgery. Materials and methodsThe system consists of MR image guidance [interactive scan control (ISC) imaging, three-dimensional (3-D) navigation, and preoperative planning], an MR-compatible operating table, and an MR-compatible master–slave surgical manipulator that can enter the MR gantry. Using this system, we performed in vivo experiments with MR image-guided laparoscopic puncture on three pigs. We used a mimic tumor made of agarose gel and with a diameter of approximately 2cm. ResultsAll procedures were successfully performed. The operator only advanced the probe along the guidance device of the manipulator, which was adjusted on the basis of the preoperative plan, and punctured the target while maintaining the operative field using robotic forceps. The position of the probe was monitored continuously with 3-D navigation and 2-D ISC images, as well as the MR-compatible laparoscope. The ISC image was updated every 4s; no artifact was detected. ConclusionA newly developed MR image-guided surgical robotic system is feasible for an operator to perform safe and precise minimally invasive procedures.
    International Journal of Computer Assisted Radiology and Surgery 01/2008; 2(6):317-325. · 1.36 Impact Factor
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    ABSTRACT: We have developed a wedge prism 3D endoscope moving its FOV with the rotation of the prisms to realize safe and precise robotic assisted laparoscopic surgery. However, it is difficult to perform image registration between preoperative MRI data and endoscopic images for image guidance surgery because our endoscopic images have prism-specific distortion. In this study, we propose the algorhythms of distorsion correction of the endoscopic images. Wedge prism distortion separated from lens distortion was corrected by tracking optical rays. The linearity of image distortion correction was 0.83 in a front of view and 0.94 in a right side view. By our developed method of image distortion correction, the disadvantage of wedge prism endoscpe was improved. The wege prism 3D endoscope is useful for the image guidance system in robotic assisted minimally invasive surgery.
    12/2007: pages 750-753;
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    ABSTRACT: Finger Braille is one of tactual communication media of deafblind people. In two-handed Finger Braille, index finger, middle finger and ring finger of both hands are likened to keys of a Braille typewriter. A sender dots Braille code on the fingers of a receiver like whether he/she does the type of the Braille typewriter. Then the receiver recognizes the Braille code. In one-handed Finger Braille, the sender dots the left column of Braille code on the DIP joints of three fingers of the receiver, and then the sender dots the right column of Braille code on the PIP joints of them. Deafblind people who are skilled in Finger Braille can catch up with speech conversation and express various emotions. Because there are small nondisabled people who are skilled in Finger Braille, deafblind people communicate only with interpreters. Objective of this study is development of a Finger Braille supporting device which assists not only verbal communication but also nonverbal (emotional) communication between deafblind people and non-disabled people who are not skilled in Finger Braille. In this paper, an experiment of emotional expression of Finger Braille was carried out. And we analyzed features of emotional expression of Finger Braille and discussed algorithm of emotion recognition. The features of emotional expression were: (1) the durations of code of Joy were particularly shorter than other emotions; (2) the durations of code of Sadness were particularly longer than other emotions; (3) the finger loads of Anger were particularly bigger than other emotions. To develop emotion recognition system, we discussed algorithm of emotion recognition using the accelerometers worn by tester. According to the results of discriminant analysis, it was considered that emotion recognition using the discriminant functions and the average of posterior probabilities in a sentence was possible.
    12/2007: pages 484-487;
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    ABSTRACT: A lightweight intraoperative spectrum measurement system for 5-ALA induced PpIX fluorescence was developed. The developed system includes a semiconductor LASER for excitation light (output light wavelength: 405nm), a CCD spectrometer, optical fiber coupled on lens system and PC. The first prototype device has a bundled fiber which contains 6 excitation fibers around one measurement fiber. The second one uses a dichroic mirror which reflects blue light (λ≤550nm) and transmits other wavelength. The third one contains not only a dichroic mirror but also a long path filter (cut on: λ=570nm) and has improved mechanical strength. The weight of the first and the prototype probe is 45g, and the external diameter is 11mm.. The weight of this probe is 25g and the external diameter is 18mm. The probes can be positioned manually and measure 5-ALA induced PpIX fluorescence.
    12/2007: pages 754-757;
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    ABSTRACT: Finger Braille is one of tactual communication media of deafblind people. In finger Braille, index finger, middle finger and ring finger of both hands are likened to keys of a Braille typewriter. A sender dots Braille code on the fingers of a receiver like whether he/she does the type of the Braille typewriter. Then the receiver recognizes the Braille code. Deafblind people who are skilled in finger Braille can catch up with speech conversation and express various emotions. Because there are small non-disabled people who are skilled in finger Braille, deafblind people communicate only with interpreters. In this paper, we developed a finger Braille teaching system and designed a teaching interface which taught clauses explicitly. The teaching system recognized non-disabled people's speech and converted to Braille code. By parsing the Braille code, the teaching system retrieved clause information and segmented the Braille code into clauses. Then the dot pattern of the Braille code was displayed. By observing the dot pattern, non-disabled people dotted Finger Braille to deafblind people. An evaluation experiment between a blind person who was skilled in Finger Braille and two nondisabled people who were non-skilled in Finger Braille was carried out. The results showed that the fundamental functions (speech recognition, conversion to Braille code and clause segmentation) were practicable; the nondisabled senders could dot finger Braille accurately and communicate with the blind receiver directly. Therefore it was considered that the teaching system was effective.
    Mechatronics and Automation, 2007. ICMA 2007. International Conference on; 09/2007
  • Hongen Liao, I Sakuma, T Dohi
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    ABSTRACT: This paper describes a novel medical three-dimensional (3-D) autostereoscopic image for surgical navigation. The 3-D image created by an animated visualization of integral videography (IV), which spatially reproduces a computer generated graphical object by multiple rays through a micro convex lens array. IV can display geometrically accurate autostereoscopic images and reproduce motion parallax. This technique requires neither special glasses nor sensing device to track viewer's eyes, thus being suitable for pre-operative diagnosis and intra-operative in image-guided surgery. We summarize the development and evaluation of the IV image for the surgical navigation system in this paper. Relative landmarks-based and marker-less patient-image registration method are developed for IV image overlay navigation system. We evaluate the feasibility of the IV image by a set of phantom and volunteer experiments. Experiments demonstrated that the IV image surgical navigation system is possible to increase the accuracy of the surgical implementation and to reduce the procedure time as the result of intuitive 3D viewing.
    Complex Medical Engineering, 2007. CME 2007. IEEE/ICME International Conference on; 06/2007
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    ABSTRACT: A straight line needle trajectory is typically used in medical needle insertion for percutaneous intervention. Flexible needle steering may be able to avoid obstacles, and reach regions that are currently inaccessible using straight line trajectory. The success of flexible needle insertion in clinical application, for example, biopsy to obtain a tissue sample from human liver organ is dependent on how accurate the motion path can be planned and simulated. We developed a motion planning algorithm for flexible needle insertion with an integrative model of human liver organ, and finite element models of needle and needle-tissue interaction. The aim of image based integrative modeling is to have a unified organ model of patient comprising finite element and implicit surface models of blood vessels, normal and pathological tissues. The trajectory path can be determined in an interactive manner. The generated trajectory for flexible needles avoids obstacles (vessels) to reach target (tumor) inaccessible to rigid needles. The algorithm can also be used to simulate needle bending due to dynamic contact with tumor
    Control, Automation, Robotics and Vision, 2006. ICARCV '06. 9th International Conference on; 01/2007
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    ABSTRACT: Finger Braille is one of tactual communication medium of deafblind people. In two-handed Finger Braille, index finger, middle finger and ring finger of both hands are likened to keys of a Braille typewriter. A sender dots Braille code on the fingers of a receiver like whether he/she does the type of the Braille typewriter. Then the receiver recognizes the Braille code. Deafblind people who are skilled in Finger Braille can catch up with speech conversation and express various emotions. Because there are small non-disabled people who are skilled in Finger Braille, deafblind people communicate only with interpreters. In this study, we note one-handed Finger Braille. In one-handed Finger Braille, the sender dots the left column of Braille code on the DIP joints of three fingers of the receiver, and then the sender dots the right column of Braille code on the PIP joints of them. In this paper, we developed the Finger Braille Recognition System, which recognized deafblind people’s one-handed Finger Braille and converted to speech for non-disabled people. Non-disabled people wore small piezoelectric accelerometers on the base of index finger, middle finger and ring finger. The Recognition System detected the accelerations by dotting and recognized which fingers were dotted. Next, by parsing the recognized Braille codes, the Recognition System converted to a Japanese text. Finally, the Recognition System synthesized speech of the Japanese text. Because each accelerometer detected the acceleration by dotting of the mounted finger (self dotting) and the acceleration by dotting of the other fingers (cross talk). The Recognition System was necessary to recognize the acceleration by self dotting. We analyzed the accelerations dotted by an interpreter and derived the algorithm of recognition of dotted fingers. Estimated accuracy of recognition was 93.4%. Therefore it was considered that the algorithm was effective.
    12/2006: pages 2935-2938;
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    ABSTRACT: Laparoscopic surgery has continued to gain popularity in almost all fields of abdominal surgery, and robotic systems have been introduced in general surgery. Naviot is a new remote-controlled laparoscope manipulator system controlled by the operator's hand. This study assessed its introduction into clinical practice. A group of 10 consecutive patients with cholelithiasis underwent laparoscopic cholecystectomy assisted by the Naviot system (Naviot group). Another group of 41 patients who underwent laparoscopic cholecystectomy with a conventional human camera holder (human camera group) were selected for a comparison of their operative results with those of the Naviot group. The operative time of 89.3 +/- 27.1 min for the Naviot group was significantly longer than that of 74.8 +/- 28.1 min for the human camera group (p < 0.05). However, when the setup time for the Naviot system was excluded, the operative time was not significantly different from that for the human camera group. Other operative results showed no significant difference between the two groups. The authors believe that the new Naviot system is feasible for clinical use, and that it enables surgeons to perform solo gastrointestinal surgery.
    Surgical Endoscopy 05/2006; 20(5):753-6. · 3.43 Impact Factor

Publication Stats

377 Citations
59.71 Total Impact Points

Institutions

  • 2006–2007
    • National University of Singapore
      • Department of Mechanical Engineering
      Singapore, Singapore
  • 2000–2007
    • The University of Tokyo
      • • Graduate School of Frontier Sciences
      • • Faculty & Graduate School of Engineering
      • • Department of Precision Engineering
      Edo, Tōkyō, Japan
  • 1989–2001
    • Tokyo Denki University
      • • Division of Life Science and Engineering
      • • School of Science and Engineering
      Tokyo, Tokyo-to, Japan
  • 1996
    • Kyoritsu College of Pharmacy
      Edo, Tōkyō, Japan