Etsuko Kobayashi

• The University of Tokyo

Ultrashort burst laser pulses serve as powerful tools for precise laser processing, broadband ultrafast spectroscopy, and high-speed laser-scanning microscopy. However, the performance of conventional burst pulse generators is limited by constraints in the pulse time interval variability, pulse energy variability, pulse number variability, and over...

Autonomous soft tissue manipulation in robotic surgery remains challenging. Modeling the tool-tissue interaction, analyzing the tissue structural deformation and monitoring the biomechanical status during surgery manipulation may benefit the development of autonomous surgery; however, there are currently inadequate studies. We propose a vision-base...

Countertraction is a vital technique in laparoscopic surgery, stretching the tissue surface for incision and dissection. Due to the technical challenges and frequency of countertraction, autonomous countertraction has the potential to significantly reduce surgeons’ workload. Despite several methods proposed for automation, achieving optimal tissue...

Background Quantitative evaluation of facial aesthetics is an important but also time‐consuming procedure in orthognathic surgery, while existing 2D beauty‐scoring models are mainly used for entertainment with less clinical impact. Methods A deep‐learning‐based 3D evaluation model DeepBeauty3D was designed and trained using 133 patients' CT images...

Purpose Considering vessel deformation, endovascular navigation requires intraoperative geometric information. Mechanical intravascular ultrasound (IVUS) with an electromagnetic (EM) sensor can be used to reconstruct blood vessels with thin diameter. However, the integration design should be evaluated based on the factors affecting the reconstructi...

In this study, we prototyped the system that collects data of the movement related to falling for the analysis of the elderly persons’ falls. Focusing on the head height and acceleration of front waist as indicators for analysis of falls, we connected sensors that collects these data and the system. After detecting falls by using fall detection alg...

Purpose Preemptively estimating tissue damage is crucial for a safe surgical procedure. We previously investigated the possibility of estimating the fracture energies of biological tissues based on their elasticities. However, the reason behind the presence of these correlations is poorly understood. In this study, we investigate the effect of a ti...

Purpose: Retrograde superselective intra-arterial chemoradiotherapy is a radical treatment for advanced oral cancer. The catheter tip is placed into tumor-feeding arteries-the lingual, facial, or maxillary arteries. The diameter of the tumor-feeding arteries newly bifurcated from the external carotid artery is crucial for determining the requireme...

Purpose: Tissue deformation recovery is to reconstruct the change in shape and surface strain caused by tool-tissue interaction or respiration, which is essential for providing motion and shape information that benefits the improvement of the safety of minimally invasive surgery. The binocular vision-based approach is a practical candidate for def...

In this paper, we applied reinforcement learning algorithm to automated counter traction control in surgery. Counter traction is a surgical technique where the forceps are manipulated so that tissue in surgical field is visible and positioned suitable for operation. Since this surgical procedure is performed repeatedly during surgery, automation is...

To prevent postoperative complications in corrective surgery for foot deformities such as hallux valgus and pes planus, it is critical to quantitatively predict the postoperative standing-position plantar pressure distribution during the operation. The authors have previously proposed an intraoperative plantar pressure measurement system (IPPM) tha...

PurposePost-surgical complications are correlated to the surgeon’s technical skill level. Thus, efforts are being put in finding ways to improve the surgeon’s technical skills, such as not causing unwanted damage to tissues during surgery. In this study, we aim to investigate the possibility of estimating biological tissue damage, in view of preven...

Purpose: Tracking the position and orientation of a 4F catheter ([Formula: see text] 1.4 mm) is required in superselective intra-arterial chemotherapy (SSIAC). Tunneling magnetoresistance (TMR) sensors, which measure magnetic fields, are promising candidates because the size of the TMR sensor can be less than a few tenths of a millimeter. The purp...

To improve spatial resolution in the PET-laparoscope system for intraoperative metastatic lymph nodes detection, design of a flat panel detector was optimized using Monte Carlo simulation tools. The performance of the new fixed detector was evaluated in point radio-source and phantom experiments. The experiment result shows that the system with the...

Laparoscopic vision-based ultrasound probe tracking systems have gained considerable attention in ultrasound-guided laparoscopic surgeries as replacements for external tracking systems (e.g. optical tracking and electromagnetic tracking systems), which increase cost and setting time, require additional operation space, and introduce new limitations...

Background: Manually surgical planning becomes an increasing workload of surgeons because of the fast-growing patient population. This study introduced a machine-learning-based approach to assist surgical planning in orthognathic surgery. Methods: Both preoperative and one-year-later postoperative CT images of 56 patients were collected. A 12-la...

Many surgical robots have been investigated recently. To create safe and effective control systems for surgical robots, intraoperative biological information is required. However, this information is limited, making it difficult to predict accurate biological responses. If patient-specific models are constructed by combining multidisciplinary compu...

Background Laparoscopic lateral pelvic lymph node dissection (LPLND) in rectal cancer surgery requires considerable skill because the pelvic arteries, which need to be located to guide the dissection, are covered by other tissues and cannot be observed on laparoscopic views. Therefore, surgeons need to localize the pelvic arteries accurately before...

Robot-assisted surgeries are procedures where a physician performs surgical maneuvers by operating a robot. One of the main limitations is the difficulty in transferring the surgeon’s multiple skills onto the robotic system. Such skills include the ability to estimate the maximum applicable force before damaging the tissue. To implement this skill...

Dural suturing in transsphenoidal surgery requires well-honed technical skills. We have developed a semiautomatic dural suturing device and confirmed its effectiveness by comparing it with the conventional method. This device significantly shortens the suturing time compared with the conventional method. The dural suturing time in transsphenoidal s...

With the rapid rate of technological advancement, a growing interest in the desire to increase the autonomy of robotic surgical systems has been reported. One of the major challenges in achieving this goal is transferring a skilled surgeon's ability into the system, especially the surgeon's adaptive tissue handling skill to prevent unwanted tissue...

Recent advances in targeting cancer therapy with stimuli responsive materials provide the opportunity to reduce systemic toxicities. Targeting cancer therapy employing ultrasound with phase-change nano-droplets (PCNDs) potentially has several distinct advantages over current cancer therapeutic modalities. PCND is a liquid perfluorocarbon nanopartic...

The PET-laparoscope system has been proposed to diagnose lymph node metastases intraoperatively in gastric cancer surgeries. The system uses two detector units, a fixed detector array and a movable detector probe to acquire PET images. The detector probe can be inserted into a patient’s stomach through laparoscopic ports. A surgeon can move the det...

Superselective intraarterial infusion chemoradiotherapy is a modality of oral cancer therapy in which the artery feeding the tumor is catheterized. 3D information about the carotid artery is required to enable the surgeon to judge whether to advance, retract, or rotate the catheter. For this purpose, we proposed and conducted a model experiment to...

Background/aim: We investigated pelvic arterial deformation and shift due to intraoperative pneumoperitoneum and postural changes in an animal model. Materials and methods: Computed tomography images of pigs were acquired in different body positions (supine, head down at 5° and 10°, right lateral recumbent at 5° and 15°) before and after insuffl...

PurposeConventional positron emission tomography can be used only preoperatively to identify lymph node metastases, and hence, these growths are difficult to locate intraoperatively. Previously, an intraoperative laparoscopic coincidence imaging system, with an external fixed detector array and a detector probe that can be moved and inserted into t...

One of the commonly used techniques for drug delivery is to temporarily increase the permeability of tissue barriers. Acoustic energies such as ultrasound and shock waves are known to modulate tissue permeability. Recently, it was found that shock waves modulate the blood-brain barrier in the rat brain without injection of contrast agents such as m...

Background/Purpose Resection using a stapler is a popular approach to distal pancreatectomy. However, the resulting leakage of pancreatic juice represents a serious problem. We have developed a force‐fluorescence measurement as a first step towards the quantitative evaluation of pancreatic leakage due to tissue tearing under compression. Methods T...

Accurate force measurement during forceps manipulation is expected to have various applications such as surgical technique analysis. The calibration method is important for achieving accurate measurement. Previously, for a force measurable forceps (FMF) with 3 degrees of freedom (DOF), a calibration method using unbiased samples has been proposed....

Background Identifying laparoscopic surgical videos using artificial intelligence (AI) facilitates the automation of several currently time-consuming manual processes, including video analysis, indexing, and video-based skill assessment. This study aimed to construct a large annotated dataset comprising laparoscopic colorectal surgery (LCRS) videos...

Background: Fluid resuscitation, which is critical to counter acute hemorrhagic shock, requires prompt and accurate intravascular volume estimation for optimal fluid administration. This study aimed to evaluate whether cardiac variation of internal jugular vein (IJV), evaluated by ultrasonography, could detect hypovolemic status and predict respon...

Background: Manual landmarking is a time-consuming and highly professional work. Although some algorithm-based landmarking methods have been proposed, they lack flexibility and may be susceptible to data diversity. Methods: The CT images from 66 patients who underwent oral and maxillofacial surgery (OMS) were landmarked manually in MIMICS. Then...

The results of oral and maxillofacial surgery (OMS) significantly depend on the individual capabilities of surgeons. In this study, an autonomous surgical robot is proposed to automatically perform surgery according to a preoperative plan with the assistance of a surgeon. A three-dimensional (3D) computed tomography image of the subject's teeth was...

Background. Fluid resuscitation is crucial to counter acute haemorrhagic shock and requires prompt and accurate intravascular volume estimation for optimal fluid administration. This study aimed to evaluate whether cardiac variation of the internal jugular vein (IJV), measured by ultrasound, could detect hypovolemic status and predict response to f...

Impracticable workspaces and cumbersome hardware limit the practical application of the currently available orthognathic surgical robots in a clinical environment. In this study, a compact and lightweight six degree of freedom (DOF) robot with a workspace limitation mechanism (WLM) was developed, and this paper reports on the technical specificatio...

Intraoperative PET-laparoscope system has been proposed to locate lymph node metastasis during gastric cancer surgery. The proposed system consists of an external detector array connected to a patient’s surgical bed and a movable detector probe which is inserted into the patient’s stomach along with a laparoscope. In this study a prototype detector...

The cover image is based on the ORIGINAL ARTICLE Selective intracellular delivery of perfluorocarbon nanodroplets for cytotoxicity threshold reduction on ultrasound‐induced vaporization by Ayumu Ishijima et al., https://doi.org/10.1002/cnr2.1165.

Background Human‐related factors affect the accuracy and safety of the oral and maxillofacial surgery (OMS). This study proposed an autonomous surgical system aiming to conduct the OMS under the assistance and surveillance of the surgeon. Methods A markerless navigation module and a compact OMS robot were seamlessly integrated into this system. Th...

Background Phase‐change nanodroplets (PCNDs), which are liquid perfluorocarbon nanoparticles, have garnered much attention as ultrasound‐responsive nanomedicines. The vaporization phenomenon has been employed to treat tumors mechanically. However, the ultrasound pressure applied to induce vaporization must be low to avoid damage to nontarget tissue...

To further minimize invasiveness of surgical robot, the diameter of laparoscopic instruments should be smaller. However, it can lead to the degradation of the performance of the surgical robotic instruments/devices. Thus, we proposed modularization of surgical robotic instruments as a method to solve this problem. The robot modules are inserted fro...

Depth perturbation method for improvement of a mesoscopic epifluorescence tomography (MEFT) we previously developed was evaluated in an experimental system using biological samples. We conducted ex vivo experiments using pork chuck meat to verify the depth perturbation concept in a relatively realistic environment. Fluorescence images were acquired...

Positron emission tomography is used to diagnose gastric cancer and identify lymph node metastasis preoperatively. However, locating these lymph node metastases during surgery is difficult and usually leads to unnecessary node removal and results in a deterioration of a patient's quality of life. To improve the quality of life, intraoperative ident...

Purpose Surgical reconstructions in three dimensions are needed for treatment of foot and ankle deformities. However, surgical results might be influenced by the skill and experience of doctors which complement the limited information for reconstructions in three dimensions. To solve these, studies were carried out to measure plantar pressure distr...

Breast cancer is the most commonly diagnosed cancer in women. A strong treatment candidate is high-intensity focused ultrasound (HIFU), a non-invasive therapeutic method that has already demonstrated its promise. To improve the precision and lower the cost of HIFU treatment, our group has developed an ultrasound (US)-guided, five-degree-of-freedom...

Accurate vessel segmentation in ultrasound images is difficult to realize given the poor image quality of such images. In this study, a local-phase-based snake is proposed to improve the accuracy of vessel segmentation in ultrasound images. In the proposed snake framework, image energy is generated using the local phase of the ultrasound image. By...

Level set methods are a kind of general numerical analysis tools that are specialized for describing and controlling implicit interface dynamically. It receives widespread attention in medical image computing and analysis. There have been a lot of level set models designed and regularized for medical image segmentation. For the sake of simplicity a...

Magnetic resonance elastography (MRE) offers a noninvasive solution to visualize the mechanical properties of soft tissue, but the study suffers from expensive magnetic resonance scanning. Moreover, translating MRE wave images into soft tissue elasticity is a nontrivial issue for clinical professionals and healthcare practitioners. An interactive s...

Laparoscopic pelvic lymph node dissection is a delicate operation because pelvic arteries, which should be located first to guide the dissection, are often concealed by tissues and cannot be identified in the endoscopic view. Consequently, arteries can be damaged if they are not located accurately. To improve dissection safety and efficiency, we ha...

Here we review the preclinical evaluation methodologies of thermal induced damage to tissues caused by surgical devices. Many innovative surgical devices based on thermal energy sources have been studied to offer less invasive treatment with fewer complications. Before these devices are used clinically, their safety must be validated using various...

In an ultrasound-guided high-intensity focused ultrasound (HIFU) device, a HIFU focal error may be observed in an ultrasound pulse-echo image due to the difference between the HIFU and imaging beam aberrations occurring in the heterogeneous propagative medium, which was verified by simulating the ultrasound beams passing through an abdominal wall....

To measure the activity of tissue at the microscopic level, laminar optical tomography (LOT), which is a microscopic form of diffuse optical tomography, has been developed. However, obtaining sufficient recording speed to determine rapidly changing dynamic activity remains major challenges. For a high frame rate of the reconstructed data, we here p...

While chemotherapy is a major mode of cancer therapeutics, its efficacy is limited by systemic toxicities and drug resistance. Recent advances in nanomedicine provide the opportunity to reduce systemic toxicities. However, drug resistance remains a major challenge in cancer treatment research. Here we developed a nanomedicine composed of a phase-ch...

As liver is the venous organ, the elasticity is changed by blood distribution in the liver. Surgeons adjust the operation in accordance with the hardness of the liver. In laparoscopic surgery, however, as surgeons cannot touch liver directly, they determine its hardness based on laparoscopic images only. Although the gripping force measuring device...

Background: Many minimally invasive surgical procedures and assisting robotic systems have been developed to further minimize the number and size of incisions in the body surface. This paper presents a new idea combining the advantages of modular robotic surgery, single incision laparoscopic surgery and needlescopic surgery. Material and methods: I...

Many innovative surgical devices based on novel technologies and techniques have been studied to offer secure diagnosis and less invasive treatment with fewer complications. Before these devices are used clinically, their safety must be validated using various methods to simulate the clinical situation with reasonable accuracy. In this paper, we fo...

A self-shape estimation algorithm for a flexible ultrasonic array probe was described in the paper. Position information of each element in the array is essentially required to achieve a focal control in ultrasonic imaging process. The purpose of this study is to develop an algorithm to estimate array shape without other sensors. In our proposed al...

Background Surgical navigation technology directed at fetoscopic procedures is relatively underdeveloped compared with other forms of endoscopy. The narrow fetoscopic field of views and the vast vascular network on the placenta make examination and photocoagulation treatment of twin-to-twin transfusion syndrome challenging. Though ultrasonography i...

Background Oral and maxillofacial surgery has not been benefitting from image guidance techniques owing to the limitations in image registration. Methods A real-time markerless image registration method is proposed by integrating a shape matching method into a 2D tracking framework. The image registration is performed by matching the patient's tee...

Endoscope-assisted surgery and robot-assisted surgery are not common in cardiac surgery, particularly coronary artery bypass grafting, because of the complex nature of the procedures. We developed a new suturing device that allows for easy performance of such cardiac surgeries in comparison with conventional suturing methods. A total of 63 rabbits...

Evaluations of intravascular fluid volume are considered to be one of the most important assessments in emergency and intensive care. Focusing on pulse-induced variation of the internal jugular vein (IJV) area, i.e., cardiac variation, we investigated its correlation with various hemodynamic indices using newly developed software. Software that aut...

Phase-change nano-droplets (PCNDs) are sub-micron particles that are coated with phospholipid and contain liquid-state perfluorocarbons such as perfluoropentane (boiling point = 29 °C) and perfluorohexane (boiling point = 57 °C), which can vapourise upon application of ultrasound. The bubbles generated by such reactions can serve as ultrasound cont...

Single photon emission computed tomography (SPECT) is a popular modality in clinic for liver function evaluation, but it is challenging for computerized segmentation and analysis of SPECT images. Most conventional technologies including mean shift and level set methods are not efficient due to weak contrast and ambiguous boundaries. We propose a ne...

This work presents an intraoperative method for registration of 3D ultrasound images to surgical navigation systems. Unlike conventional methods that rely on pre-calibration of ultrasound probe in a laboratory environment using a calibration rig, the proposed method is designed to self-register with a tracking system in an operating room. It exploi...

TURBT(TransUrethral Resection of Bladder Tumor) is now popular surgical treatment for bladder tumor, but devices currently used in this operation have two problems; one is that because bladder tumor tissue is cut into several pieces in TURBT with the devices, there is a risk of dissemination of tumor, and the other is that they increase a risk to d...

Arrhythmia surgery is performed to treat serious arrhythmia such as atrial fibrillation and ventricular tachycardia unable to be treated by catheter ablation. Mapping devices are needed to find electrical abnormal regions. Open heart surgery is invasive for patient's body. Recently, endoscopic arrhythmia surgery is reported as minimally invasive su...

Minimum invasive surgery can benefit from surgical visual-ization, which is achieved by either virtual reality or augmented reality. We previously proposed an integrated 3D image overlay based surgical visualization solution including 3D image rendering, distortion correction , and spatial projection. For correct spatial projection of the 3D image,...

Background: Visualization of the vast placental vasculature is crucial in fetoscopic laser photocoagulation for twin-to-twin transfusion syndrome treatment. However, vasculature mosaic is challenging due to the fluctuating imaging conditions during fetoscopic surgery. Method: A scene adaptive feature-based approach for image correspondence in fr...

Minimally invasive therapies by applying cavitation bubbles, such as histotripsy and gene transfer, have recently attracted attention. As a method to generate bubbles, the use of expansion waves is expected to be more effective than using shock waves or ultrasound. However, few studies have confirmed the effectiveness of expansion waves in generati...

A novel material reconstruction method combining finite element (FE)-based direct inverse method and non-linear optimization algorithm is proposed for elasticity imaging of biological soft tissue. The biological soft tissue is represented using Neo-Hookean hyperelastic model. The FE-based direct inverse method provides an estimation of material par...

Fluorescence molecular tomography (FMT) imaging can be used to determine the location, size, and biodistribution of fluorophore biomarkers inside tissues. Yet when using FMT in the reflectance geometry it is challenging to accurately localize fluorophores. A depth perturbation method is proposed to determine the centroid of fluorophore inside a tis...

Autostereoscopic 3D image overlay for augmented reality (AR) based surgical navigation has been studied and reported many times. For the purpose of surgical overlay, the 3D image is expected to have the same geometric shape as the original organ, and can be transformed to a specified location for image overlay. However, how to generate a 3D image w...

Magnetic resonance elastography (MRE) is a promising modality for in vivo quantification and visualization of soft tissue elasticity. It involves three stages of processes for (1) external excitation, (2) wave imaging and (3) elasticity reconstruction. One of the important issues to be addressed in MRE is wave image processing and enhancement. In t...

We developed a pulsed laser-induced liquid jet (LILJ) system to dissect tumor tissues while preserving fine blood vessels within deep and narrow working spaces and evaluated its utility and safety. However, the hand applicator of LILJ is heavy for the operator because of the torque generated by some of the accessories. Consequently, the operator ca...

This work introduces a self-contained framework for endoscopic camera tracking by combining 3D ultrasonography with endoscopy. The approach can be readily incorporated into surgical workflows without installing external tracking devices. By fusing the ultrasound-constructed scene geometry with endoscopic vision, this integrated approach addresses i...

Recently, fluid jets have become widely used in medical devices and have been created and evaluated in clinical environments. Such devices are classified into two broad groups; those adopting continuous jets and those adopting discrete (or pulsed) jets. We developed a discrete jet device for brain cancer treatment, called a laser-induced liquid jet...

In femoral fracture reduction, orthopedic surgeons must pull distal bone fragments with great traction force and return them to their correct positions, by referring to 2D-fluoroscopic images. Since this method is physically burdensome, the introduction of robotic assistance is desirable. While such robots have been developed, adequate control meth...

Transsphenoidal surgery is currently employed to treat complex lesions beyond the sella turcica; however, the procedure can be limited by difficulties encountered in dealing with small blood vessels, deep and narrow working spaces, and awkward working angles. To overcome these problems, we have developed a pulsed laser-induced liquid jet system tha...

Estimating bio-distribution of fluorophore in tissue is challenging. In this paper, we demonstrated that our depth perturbation method can accurately determine depth of fluorophore located in tissue as deep as 5.8 mm by phantom experiments.

In this study, we aimed to develop a stereoscopic fluorescence camera system for simultaneous evaluation of wall motion and tissue perfusion using indocyanine green (ICG) fluorescence imaging. The system consists of two high-speed stereo cameras, an excitation lamp, and a computer for image processing. Evaluation experiments demonstrated that the s...

Background This study presents a tracker-less image-mapping framework for surgical navigation motivated by the clinical need for intuitive visual guidance during minimally invasive fetoscopic surgery.MethodsA navigation framework mapping 2D endoscopic vision to a 3D ultrasound image model is proposed. This maps an endoscopic image onto a 3D placent...