Rib region detection for scanning path planning for fully automated robotic abdominal ultrasonography.

PURPOSE: Scanning path planning is an essential technology for fully automated ultrasound (US) robotics. During biliary scanning, the subcostal boundary is critical body surface landmarks for scanning path planning but are often invisible, depending on the individual. This study developed a method of estimating the rib region for scanning path planning toward fully automated robotic US systems. METHODS: We proposed a method for determining the rib region using RGB-D images and respiratory variation. We hypothesized that detecting the rib region would be possible based on changes in body surface position due to breathing. We generated a depth difference image by finding the difference between the depth image taken at the resting inspiratory position and the depth image taken at the maximum inspiratory position, which clearly shows the rib region. The boundary position of the subcostal was then determined by applying training using the YOLOv5 object detection model to this depth difference image. RESULTS: In the experiments with healthy subjects, the proposed method of rib detection using the depth difference image marked an intersection over union (IoU) of 0.951 and average confidence of 0.77. The average error between the ground truth and predicted positions was 16.5 mm in 3D space. The results were superior to rib detection using only the RGB image. CONCLUSION: The proposed depth difference imaging method, which measures respiratory variation, was able to accurately estimate the rib region without contact and physician intervention. It will be useful for planning the scan path during the biliary imaging.

In-bore MRI-compatible Transrectal Ultrasound and Photoacoustic Imaging.

Prostate cancer (PCa) is known as one of the most prevalent and fatal cancer types. This report describes an MRI-compatible photoacoustic/ultrasound (PA/US) imaging platform to improve the diagnosis of PCa. In the proposed solution, PA imaging, which offers real-time, non-ionizing imaging with high sensitivity and specificity, is combined with MRI, aiming to overcome PA's limited field of view (FOV) and make PA scalable for translation to clinical settings. Central to the design of the system is a reflector-based transrectal probing mechanism composed of MRI-compatible materials. The linear transducer with a center hole for optical fiber delivery can be mechanically actuated to form a multi-angled scan, allowing PA/US imaging from varied cross-sectional views. Performance assessment was carried out in phantom and ex-vivo settings. We confirmed the MRI compatibility of the system and demonstrated the feasibility of its tri-modal imaging capability by visualizing a tubing phantom containing contrast agents. The ex-vivo evaluation of targeted tumor imaging capability was performed with a mouse liver sample expressing PSMA-positive tumors, affirming the system's compatibility in spectroscopic PA (sPA) imaging with biological tissue. These results support the feasibility of the in-bore MRI-compatible transrectal PA and US and the potential clinical adaptability.

Design and Evaluation of a Puncture Control Method for the Deflection of Ultrafine Needles due to Interfacial Passage-Proposal of Puncture Control Strategy for Increasing.

With the demand for sophisticated techniques to easily prevent the deflection of needles, robotic CT (computed tomography)-guided puncture with an ultrafine needle is being investigated. Quantification of deflection is essential for accurate puncture with ultrafine needles. Research on the quantification of deflection caused by tissue reaction forces to which the beveled surface of the needle tip is in progress, and this method has been applied for deflection reduction and needle steering within the tissue. However, when the needle tip passes through a tissue boundary, the needle deflects regardless of the direction of the beveled surface. Although several methods have been proposed to reduce the deflection caused by the boundary surface, no curve puncture method has been constructed using the deflection. This work aimed to construct a refraction model that can back-calculate the curved path from the body surface to the target. Assumptions of the refraction model were made based on the results of ex vivo examination, and the model was validated through in vivo examination. A refraction model in which the refraction angle is linearly proportional to the needle penetration angle relative to the boundary was hypothesized. Validation test revealed that the correlation coefficient exceeded 0.9, which was similar to that of the model and suggested the biological adaptability of the proposed model. A curve puncture method using this refraction model will be developed in the future.

Study on method of organ section retention and tracking through deep learning in automated diagnostic and therapeutic robotics.

PURPOSE: In high-intensity focused ultrasound (HIFU) treatment of the kidney and liver, tracking the organs is essential because respiratory motions make continuous cauterization of the affected area difficult and may cause damage to other parts of the body. In this study, we propose a tracking system for rotational scanning, and propose and evaluate a method for estimating the angles of organs in ultrasound images. METHODS: We proposed AEMA, AEMAD, and AEMAD++ as methods for estimating the angles of organs in ultrasound images, using RUDS and a phantom to acquire 90-degree images of a kidney from the long-axis image to the short-axis image as a data set. Six datasets were used, with five for preliminary preparation and one for testing, while the initial position was shifted by 2 mm in the contralateral axis direction. The test data set was evaluated by estimating the angle using each method. RESULTS: The accuracy and processing speed of angle estimation for AEMA, AEMAD, and AEMAD++ were 23.8% and 0.33 FPS for AEMAD, 32.0% and 0.56 FPS for AEMAD, and 29.5% and 3.20 FPS for AEMAD++, with tolerance of ± 2.5 degrees. AEMAD++ offered the best speed and accuracy. CONCLUSION: In the phantom experiment, AEMAD++ showed the effectiveness of tracking the long-axis image of the kidney in rotational scanning. In the future, we will add either the area of surrounding organs or the internal structure of the kidney as a new feature to validate the results.

Diagnostic posture control system for seated-style echocardiography robot.

PURPOSE: Conventional robotic ultrasound systems were utilized with patients in supine positions. Meanwhile, the limitation of the systems is that it is difficult to evacuate the patients in case of emergency (e.g., patient discomfort and system failure) because the patients are restricted between the robot system and bed. Therefore, we validated a feasibility study of seated-style echocardiography using a robot. METHOD: Preliminary experiments were conducted to verify the following two points: (1) diagnostic image quality due to the sitting posture angle and (2) physical load due to the sitting posture angle. For reducing the physical burden, two unique mechanisms were incorporated into the system: (1) a leg pendulum base mechanism to reduce the load on the legs when the lateral bending angle increases, and (2) a roll angle division by a lumbar lateral bending and thoracic rotation mechanisms. RESULTS: Preliminary results demonstrated that adjusting the diagnostic posture angle allowed to obtain the views, including cardiac disease features, as in the conventional examination. The results also demonstrated that the body load reduction mechanism incorporated in the results could reduce the physical load in the seated echocardiography. Furthermore, this system was shown to provide greater safety and shorter evacuation times than conventional systems. CONCLUSION: These results indicate that diagnostic echocardiographic images can be obtained by seated-style echocardiography. It was also suggested that the proposed system can reduce the physical load and guarantee a sense of safety and emergency evacuation. These results demonstrated the possibility of the usage of the seated-style echocardiography robot.

Suppression of Clothing-Induced Acoustic Attenuation in Robotic Auscultation.

For patients who are often embarrassed and uncomfortable when exposing their breasts and having them touched by physicians of different genders during auscultation, we are developing a robotic system that performs auscultation over clothing. As the technical issue, the sound obtained through the clothing is often attenuated. This study aims to investigate clothing-induced acoustic attenuation and develop a suppression method for it. Because the attenuation is due to the loss of energy as sound propagates through a medium with viscosity, we hypothesized that the attenuation is improved by compressing clothing and shortening the sound propagation distance. Then, the amplitude spectrum of the heart sound was obtained over clothes of different thicknesses and materials in a phantom study and human trial at varying contact forces with a developed passive-actuated end-effector. Our results demonstrate the feasibility of the attenuation suppression method by applying an optimum contact force, which varied according to the clothing condition. In the phantom experiments, the attenuation rate was improved maximumly by 48% when applying the optimal contact force (1 N). In human trials, the attenuation rate was under the acceptable attenuation (40%) when applying the optimal contact force in all combinations in each subject. The proposed method promises the potential of robotic auscultation toward eliminating gender bias.

Body surface registration considering individual differences with non-rigid iterative closest point.

PURPOSE: In telemedicine such as remote auscultation, patients themselves or non-medical people such as patient's parents need to place the stethoscope on their body surface in appropriate positions instead of the physicians. Meanwhile, as the position depends on the individual difference of body shape, there is a demand for the efficient navigation to place the medical equipment. METHODS: In this paper, we have proposed a non-rigid iterative closest point (ICP)-based registration method for localizing the auscultation area considering the individual difference of body surface. The proposed system provides the listening position by applying the body surface registration between the patient and reference model with the specified auscultation area. Our novelty is that selecting the utilized reference model similar to the patient body among several types of the prepared reference model increases the registration accuracy. RESULTS: Simulation results showed that the registration error increases due to deviations of the body shape between the targeted models and reference model. Experimental results demonstrated that the proposed non-rigid ICP registration is capable of estimating the auscultation area with average error 5-19 mm when selecting the most similar reference model. The statistical analysis showed high correlation between the registration accuracy and similarity of the utilized models. CONCLUSION: The proposed non-rigid ICP registration is a promising new method that provides accurate auscultation area takes into account the individual difference of body shape. Our hypothesis that the registration accuracy depends on the similarity of both body surfaces is validated through simulation study and human trial.

Towards fully automated robotic platform for remote auscultation.

BACKGROUND: Since most developed countries are facing an increase in the number of patients per healthcare worker due to a declining birth rate and an ageing population, relatively simple and safe diagnosis tasks may need to be performed using robotics and automation technologies, without specialists and hospitals. This study presents an automated robotic platform for remote auscultation, which is a highly cost-effective screening tool for detecting abnormal clinical signs. METHOD: The developed robotic platform is composed of a 6-degree-of-freedom cooperative robotic arm, LiDAR camera, and a spring-based mechanism holding an electric stethoscope. The platform enables autonomous stethoscope positioning based on external body information acquired using the LiDAR camera-based multi-way registration; the platform also ensures safe and flexible contact, maintaining the contact force within a certain range through the passive-actuated mechanism. RESULTS: Our preliminary results confirm that the robotic platform enables estimation of the landing positions required for cardiac examinations based on the depth and landmark information of the body surface. It also handles the stethoscope while maintaining the contact force without relying on the push-in displacement by the robotic arm. CONCLUSION: The developed robotic platform enables the estimation of the landing positions and handling the stethoscope while maintaining the contact force, which promises the potential of automatic remote auscultation.

A VS ultrasound diagnostic system with kidney image evaluation functions.

PURPOSE: An inevitable feature of ultrasound-based diagnoses is that the quality of the ultrasound images produced depends directly on the skill of the physician operating the probe. This is because physicians have to constantly adjust the probe position to obtain a cross section of the target organ, which is constantly shifting due to patient respiratory motions. Therefore, we developed an ultrasound diagnostic robot that works in cooperation with a visual servo system based on deep learning that will help alleviate the burdens imposed on physicians. METHODS: Our newly developed robotic ultrasound diagnostic system consists of three robots: an organ tracking robot (OTR), a robotic bed, and a robotic supporting arm. Additionally, we used different image processing methods (YOLOv5s and BiSeNet V2) to detect the target kidney location, as well as to evaluate the appropriateness of the obtained ultrasound images (ResNet 50). Ultimately, the image processing results are transmitted to the OTR for use as motion commands. RESULTS: In our experiments, the highest effective tracking rate (0.749) was obtained by YOLOv5s with Kalman filtering, while the effective tracking rate was improved by about 37% in comparison with cases without such filtering. Additionally, the appropriateness probability of the ultrasound images obtained during the tracking process was also the highest and most stable. The second highest tracking efficiency value (0.694) was obtained by BiSeNet V2 with Kalman filtering and was a 75% improvement over the case without such filtering. CONCLUSION: While the most efficient tracking achieved is based on the combination of YOLOv5s and Kalman filtering, the combination of BiSeNet V2 and Kalman filtering was capable of detecting the kidney center of gravity closer to the kidney's actual motion state. Furthermore, this model could also measure the cross-sectional area, maximum diameter, and other detailed information of the target kidney, which meant it is more practical for use in actual diagnoses.

Concentric-ring arrays for forward-viewing ultrasound imaging.

Purpose: Current ultrasound (US)-image-guided needle insertions often require an expertized technique for clinicians because the performance of tasks in a three-dimensional space using two-dimensional images requires operators to cognitively maintain the spatial relationships between the US probe, the needle, and the lesion. This work presents forward-viewing US imaging with a ring array configuration to enable needle interventions without requiring the registration between tools and targets. Approach: The center-open ring array configuration allows the needle to be inserted from the center of the visualized US image, providing simple and intuitive guidance. To establish the feasibility of the ring array configuration, the design parameters causing the image quality, including the radius of the center hole and the number of ring layers and transducer elements, were investigated. Results: Experimental results showed successful visualization, even with a hole in the transducer elements, and the target visibility was improved by increasing the number of ring layers and the number of transducer elements in each ring layer. Reducing the hole radius improved the region's image quality at a shallow depth. Conclusions: Forward-viewing US imaging with a ring array configuration has the potential to be a viable alternative to conventional US image-guided needle insertion methods.

Development of Needle Guide Unit Considering Buckling Bone-Perforation Control Strategy Based on Computed Tomography-Guided Needle Insertion Robot.

A computed tomography (CT)-guided robotic assistance system is useful for needle insertion into metastatic carcinoma of vertebrae, which has limited pathways. However, the use of conventional needles in this procedure can result in bone fracture in the perforation area caused by the reaction force of the inserted needle. In this study, we developed a multistage retractable needle guide unit that avoids the buckling and crushing of the needle tip that commonly occur in 25-gauge ultrafine needles. First, we clarified a relationship between the shape of the guide and the termination factor when a buckling load is applied to the needle. Next, we revealed the point at which the plastic deformation of the needle occurred when the bone is drilled. Based on these results, we developed a guide unit with the reaction force set to an appropriate value. Finally, an evaluation test of bone needle insertion was conducted on porcine vertebrae with using the developed needle guide unit equipped with a 25-gauge needle. The needle penetrated the vertebra without buckling or crushing of the needle tip, which demonstrates the value of this multistage retractable needle guide unit when ultrafine needles are required. Clinical Relevance- Cancer tumors often metastasize to bones. There is a treatment called percutaneous vertebroplasty which restores the patient's quality of life by injecting poly (methyl methacrylate) (PMMA) into a bone. It helps to reinforce the bone that has become brittle due to cancer metastasis to the vertebral body or osteoporosis. This treatment often involves puncture of the vertebrae but the limited puncture pathway makes it difficult to perform the treatment manually. Therefore it is necessary to construct a system that supports accurate puncture by a robot such as the proposed method.

Actuated Reflector-Based 3-D Ultrasound Imaging With Synthetic Aperture Focusing.

The 3-D ultrasound (US) imaging addresses the limitation in field-of-view (FOV) in conventional 2-D US imaging by providing 3-D viewing of the anatomy. The 3-D US imaging has been extensively adapted for diagnosis and image-guided surgical intervention. However, conventional approaches to implement 3-D US imaging require either expensive and sophisticated 2-D array transducers or external actuation mechanisms to move a 1-D array mechanically. Here, we propose a 3-D US imaging mechanism using an actuated acoustic reflector instead of the sensor elements for volume acquisition with significantly extended 3-D FOV, which can be implemented with simple hardware and compact size. To improve image quality on the elevation plane, we implemented the synthetic aperture focusing (SAF) method according to the diagonal geometry of the virtual element array in the proposed imaging mechanism for elevation beamforming. We first evaluated the proposed imaging mechanism and SAF with simulated point targets and cyst targets. The results of point targets suggested improved image quality on the elevation plane, and the results of cysts targets demonstrated a potential to improve 3-D visualization of human anatomy. We built a prototype imaging system with a 3-D FOV of 38 mm (lateral) by 38 mm (elevation) by 50 mm (axial) and collected data in imaging experiments with phantoms. Experimental data showed consistency with simulation results. The SAF method enhanced quantifying the cyst volume size in the breast mimicking phantom compared with no elevation beamforming. These results suggested that the proposed 3-D US imaging mechanism could potentially be applied in clinical scenarios.

Acoustic-resolution photoacoustic microscope based on compact and low-cost delta configuration actuator.

The state-of-the-art configurations for acoustic-resolution photoacoustic (PA) microscope (AR-PAM) are large in size and expensive, hindering their democratization. While previous research on AR-PAMs introduced a low-cost light source to reduce the cost, few studies have investigated the possibility of optimizing the sensor actuation, particularly for the AR-PAM. Additionally, there is an unmet need to evaluate the image quality deterioration associated with the actuation inaccuracy. A low-cost actuation device is introduced to reduce the system size and cost of the AR-PAM while maintaining the image quality by implementing the advanced beamformers. This work proposes an AR-RAM incorporating the delta configuration actuator adaptable from a low-cost off-the-shelf 3D printer as the sensor actuation device. The image degradation due to the data acquisition positioning inaccuracy is evaluated in the simulation. We further assess the mitigation of potential actuation precision uncertainty through advanced 3D synthetic aperture focusing algorithms represented by the Delay-and-Sum (DAS) with Coherence Factor (DAS+CF) and Delay-Multiply-and-Sum (DMAS) algorithms. The simulation study demonstrated the tolerance of image quality on actuation inaccuracy and the effect of compensating the actuator motion precision error through advanced reconstruction algorithms. With those algorithms, the image quality degradation was suppressed to within 25% with the presence of 0.2 mm motion inaccuracy. The experimental evaluation using phantoms and an ex-vivo sample presented the applicability of low-cost delta configuration actuators for AR-PAMs. The measured full width at half maximum of the 0.2 mm diameter pencil-lead phantom were 0.45 ± 0.06 mm, 0.31 ± 0.04 mm, and 0.35 ± 0.07 mm, by applying the DAS, DAS+CF, and DMAS algorithms, respectively. AR-PAMs with a compact and low-cost delta configuration provide high-quality PA imaging with better accessibility for biomedical applications. The research evaluated the image degradation contributed by the actuation inaccuracy and suggested that the advanced beamformers are capable of suppressing the actuation inaccuracy.

Robotic Cytology using Extra-Fine Needles : -Proposal of Puncture Control Strategy for Increasing Collection Amount.

Fine needle aspiration cytology requires accurate needle insertion into a tumor and sufficient amount collection of samples, which highly depends on the skill of the physician. The advantage of the diagnosis is to minimize the tissue damage with the fine needle, while, when the amount of the sample sucked from the lesion is not enough for the definite diagnosis, the procedure has to be repeated until satisfying them. Although numerous research reported a robot-assisted insertion method to improve the accuracy of needle placement with fine needles, there was less research to address the efficient tissue collection. Ideally, the amount of the samples can be satisfied for the diagnosis even if an extra-fine needle (e.g. 25-gauge) is used. This paper proposes a novel needle insertion method for increasing the amount of the tissue sample with the extra-fine needle. The proposed insertion method comprises the round-trip insertion motion and trajectory rerouting with the nature of the bevel-tipped needle. The phantom study's result showed the equivalency of the aspiration amount between a physician's manual procedure with a 22-gauge needle and the proposed method with a 25-gauge needle (4.5 ± 1.0 mg vs 5.1 ± 0.7 mg). The results suggested that the proposed robotic aspiration method can increase the sampling amount with the extra-fine needle in the fine needle aspiration cytology.

Tele-Operative Low-Cost Robotic Lung Ultrasound Scanning Platform for Triage of COVID-19 Patients.

Novel severe acute respiratory syndrome coronavirus 2 (COVID-19) has become a pandemic of epic proportions, and global response to prepare health systems worldwide is of utmost importance. 2-dimensional (2D) lung ultrasound (LUS) has emerged as a rapid, noninvasive imaging tool for diagnosing COVID-19 infected patients. Concerns surrounding LUS include the disparity of infected patients and healthcare providers, and importantly, the requirement for substantial physical contact between the patient and operator, increasing the risk of transmission. New variants of COVID-19 will continue to emerge; therefore, mitigation of the virus's spread is of paramount importance. A tele-operative robotic ultrasound platform capable of performing LUS in COVID-19 infected patients may be of significant benefit, especially in low- and middle-income countries. The authors address the issues mentioned above surrounding the use of LUS in COVID-19 infected patients and the potential for extension of this technology in a resource-limited environment. Additionally, first-time application, feasibility, and safety were validated in healthy subjects. Preliminary results demonstrate that our platform allows for the successful acquisition and application of robotic LUS in humans.

A component of the septation initiation network complex, AaSepM, is involved in multiple cellulose-responsive signaling pathways in Aspergillus aculeatus.

Various carbohydrate-active enzymes in Aspergillus are produced in response to physiological inducers, which is regulated at the transcriptional level. To elucidate the induction mechanisms in Aspergillus, we screened for new regulators involved in cellulose-responsive induction from approximately 10,000 Aspergillus aculeatus T-DNA-inserted mutants. We constructed the T-DNA-inserted mutant library using the host strain harboring the orotidine 5'-monophosphate decarboxylase gene (pyrG) under the control of the FIII-avicelase gene (cbhI) promoter. Thus, candidate mutants deficient in cellulose-responsive induction were positively screened via counter selection against 5-fluoroorotic acid (5-FOA). Among less than two hundred 5-FOA-resistant mutants, one mutant that the T-DNA inserted into the AasepM locus reduced the cbhI expression in response to cellulose. Since AaSepM is similar to Schizosaccharomyces pombe Cdc14p (E-value, 2e-20; identities, 33%), which is a component of the septation initiation network (SIN)-complex, we constructed an AasepM deletion mutant (ΔAasepM). We analyzed the expression of cellulase and xylanase genes in response to cellulose, septation, and conidiation in ΔAasepM. The AasepM deletion leads to delayed septation and decreased formation of the conidium chain in A. aculeatus but does not affect hyphal growth on minimal media. We also confirmed AaSepM's involvement in multiple cellulose-responsive signaling pathways of cellulase and xylanase genes under the control of the ManR-dependent, XlnR-dependent, and ManR- and XlnR-independent signaling pathways. KEY POINTS : • A new regulator for cellulolytic gene expression has been identified. • AaSepM is involved in septation and conidiation in A. aculeatus. • AasepM is involved in multiple cellulose-responsive signaling pathways.

Anatomical Feature-Based Lung Ultrasound Image Quality Assessment Using Deep Convolutional Neural Network.

Lung ultrasound (LUS) has been used for point-of-care diagnosis of respiratory diseases including COVID-19, with advantages such as low cost, safety, absence of radiation, and portability. The scanning procedure and assessment of LUS are highly operator-dependent, and the appearance of LUS images varies with the probe's position, orientation, and contact force. Karamalis et al. introduced the concept of ultrasound confidence maps based on random walks to assess the ultrasound image quality algorithmically by estimating the per-pixel confidence in the image data. However, these confidence maps do not consider the clinical context of an image, such as anatomical feature visibility and diagnosability. This work proposes a deep convolutional network that detects important anatomical features in an LUS image to quantify its clinical context. This work introduces an Anatomical Feature-based Confidence (AFC) Map, quantifying an LUS image's clinical context based on the visible anatomical features. We developed two U-net models, each segmenting one of the two classes crucial for analyzing an LUS image, namely 1) Bright Features: Pleural and Rib Lines and 2) Dark Features: Rib Shadows. Each model takes the LUS image as input and outputs the segmented regions with confidence values for the corresponding class. The evaluation dataset consists of ultrasound images extracted from videos of two sub-regions of the chest above the anterior axial line from three human subjects. The feature segmentation models achieved an average Dice score of 0.72 on the model's output for the testing data. The average of non-zero confidence values in all the pixels was calculated and compared against the image quality scores. The confidence values were different between different image quality scores. The results demonstrated the relevance of using an AFC Map to quantify the clinical context of an LUS image.

Ring-arrayed Forward-viewing Ultrasound Imaging System: A Feasibility Study.

Current standard workflows of ultrasound (US)-guided needle insertion require physicians to use their both hands: holding the US probe to locate interested areas with the non-dominant hand and the needle with the dominant hand. This is due to the separation of functionalities for localization and needle insertion. This requirement does not only make the procedure cumbersome, but also limits the reliability of guidance given that the positional relationship between the needle and US images is unknown and interpreted with their experience and assumption. Although the US-guided needle insertion may be assisted through navigation systems, recovery of the positional relationship between the needle and US images requires the usage of external tracking systems and image-based tracking algorisms that may involve the registration inaccuracy. Therefore, there is an unmet need for the solution that provides a simple and intuitive needle localization and insertion to improve the conventional US-guided procedure. In this work, we propose a new device concept solution based on the ring-arrayed forward-viewing (RAF) ultrasound imaging system. The proposed system is comprised with ring-arrayed transducers and an open whole inside the ring where the needle can be inserted. The ring array provides forward-viewing US images, where the needle path is always maintained at the center of the reconstructed image without requiring any registration. As the proof of concept, we designed single-circle ring-arrayed configurations with different radiuses and visualized point targets using the forward-viewing US imaging through simulations and phantom experiments. The results demonstrated the successful target visualization and indicates the ring-arrayed US imaging has a potential to improve the US-guided needle insertion procedure to be simpler and more intuitive.

Robotic fetal ultrasonography platform with a passive scan mechanism.

PURPOSE: The shortage of obstetricians and gynecologists has intensified in developed countries. Our long-term goal is to develop a robotic prenatal care platform for automatic ultrasound (US) scanning to improve the workflow efficiency of obstetricians and gynecologists. This paper develops a hardware platform for the positioning of the US probe to obtain diagnostic US images while satisfying safety requirements of the fetus and pregnant woman. METHOD: The proposed system includes a mechanism that maintains the contact force in a certain range and passively adjusts the US probe posture relative to the body surface. The system is designed according to clinical survey data. For proof of concept, we conducted a robotic US scan with an agar phantom and three pregnant women under the operation of a physician. RESULTS: Experimental results show the passive US scan motion followed the phantom surface with an acceptable contact force (< 15 N). Clinical trials were safely carried out with observations of fetal body parts. CONCLUSION: Our proposed platform acquired US images with satisfactory contact forces in the phantom study. The feasibility of the platform was demonstrated in a clinical study.

Fine needle insertion method for minimising deflection in lower abdomen: In vivo evaluation.

BACKGROUND: Fine needle insertion in the lower abdomen is difficult because of complex deflections and few image feedbacks. We aim to develop an approach for generating a straight insertion path by minimizing the needle deflection robustly based on a preoperative computer tomography (CT) image. METHOD: This study presents two approaches: an insertion control strategy that performs both vibration and rotation-assisted needle insertions and a preoperative insertion path planning for determining an optimal insertion path based on insertion angles at each tissue boundary. Those proposed approaches were evaluated through an in vivo experiment with a Landrace mini-pig. We compered the following: (1) the deflection with and without the insertion control strategy in different 10 insertion paths and (2) the score calculated by the path planning and the actual deflection in the 10 insertion paths. RESULTS: The result shows that the deflection can be reduced significantly by applying the insertion control strategy in the optimal insertion path calculated by the path planning. CONCLUSION: The proposed method can decrease fine needle deflections in the lower abdomen, which has the potential for accurate and safety procedures without real-time CT imaging.