Navid Shahriari, PhD

Although wearable sensors are omnipresent in consumer market nowadays, due to wearability and comfort issues they often avoid human head. Reliable and robust estimation of human cognitive states and traits, unfortunately, requires positioning electrodes at this sensitive location to capture electrical activity of the brain, eyes, and/or (facial) muscles. Novel augmented and virtual reality (AR/VR) use cases provide a new area that could lower the acceptance threshold of users toward head-worn… Meer weergeven

Although wearable sensors are omnipresent in consumer market nowadays, due to wearability and comfort issues they often avoid human head. Reliable and robust estimation of human cognitive states and traits, unfortunately, requires positioning electrodes at this sensitive location to capture electrical activity of the brain, eyes, and/or (facial) muscles. Novel augmented and virtual reality (AR/VR) use cases provide a new area that could lower the acceptance threshold of users toward head-worn devices and open new application spaces. To foster this new trend, head-mounted solutions have to offer clear benefits to users and also provide convenience and wearing comfort. Two prototype solutions are discussed in more detail, an AR-enhanced glasses and a VR-compatible electroencephalography (EEG) headset, along with the methods used to assess and improve data quality such that reliable information on brain and eye activity can be extracted. Systems and methods are evaluated through large-scale user experiments during a music festival (Lowlands) in case of AR glasses and a simulated real-life scenario for VR EEG solution. Improvements achieved in ergonomics and signal integrity are clear over state of the art, however, further adaptations of the solutions toward final use case could lead to increased end-user benefits. Minder weergeven

Needle insertion procedures under ultrasound guidance are commonly used for diagnosis and therapy. It is often critical to accurately reach a targeted region, and this can be difficult to achieve due to intraoperative tissue motion. In this letter, we present a method to steer a beveled-tip flexible needle toward a target embedded in moving tissue. Needle steering is performed using a needle insertion device attached to a robot arm. Closed-loop 3-D steering of the needle is achieved using… Meer weergeven

Needle insertion procedures under ultrasound guidance are commonly used for diagnosis and therapy. It is often critical to accurately reach a targeted region, and this can be difficult to achieve due to intraoperative tissue motion. In this letter, we present a method to steer a beveled-tip flexible needle toward a target embedded in moving tissue. Needle steering is performed using a needle insertion device attached to a robot arm. Closed-loop 3-D steering of the needle is achieved using tracking of an artificial target in 2-D ultrasound images and tracking of the needle tip position and orientation with an electromagnetic tracker. Tissue motion compensation is performed using force feedback to reduce targeting error and forces applied to the tissue. The method uses a mechanics-based interaction model that is updated online. A novel control law using task functions is proposed to fuse motion compensation, steering via base manipulation and tip-based steering. Validation of the tracking and steering algorithms are performed in gelatin phantom and bovine liver. Tissue motion up to 15 mm is applied and average targeting error is 1.2 ± 0.8 mm and 2.5 ± 0.7 mm in gelatin and liver, respectively, which is sufficiently accurate for commonly performed needle insertion procedures. Minder weergeven

Abstract:
Lung cancer is the most common cause of cancer-related death, and early detection can reduce the mortality rate. Patients with lung nodules greater than 10 mm usually undergo a computed tomography (CT)-guided biopsy. However, aligning the needle with the target is difficult and the needle tends to deflect from a straight path. In this work, we present a CT-compatible robotic system, which can both position the needle at the puncture point and also insert and rotate the needle. The… Meer weergeven

Abstract:
Lung cancer is the most common cause of cancer-related death, and early detection can reduce the mortality rate. Patients with lung nodules greater than 10 mm usually undergo a computed tomography (CT)-guided biopsy. However, aligning the needle with the target is difficult and the needle tends to deflect from a straight path. In this work, we present a CT-compatible robotic system, which can both position the needle at the puncture point and also insert and rotate the needle. The robot has a remote-center-of-motion arm which is achieved through a parallel mechanism. A new needle steering scheme is also developed where CT images are fused with electromagnetic (EM) sensor data using an unscented Kalman filter. The data fusion allows us to steer the needle using the real-time EM tracker data. The robot design and the steering scheme are validated using three experimental cases. Experimental Case I and II evaluate the accuracy and CT-compatibility of the robot arm, respectively. In experimental Case III, the needle is steered towards 5 real targets embedded in an anthropomorphic gelatin phantom of the thorax. The mean targeting error for the 5 experiments is 1.78 ± 0.70 mm. The proposed robotic system is shown to be CT-compatible with low targeting error. Small nodule size and large needle diameter are two risk factors that can lead to complications in lung biopsy. Our results suggest that nodules larger than 5 mm in diameter can be targeted using our method which may result in lower complication rate. Minder weergeven

Needle insertion procedures are commonly performed in current clinical practice for diagnostic and therapeutic purposes. Although prevailing technology allows accurate localization of lesions, they cannot yet be precisely targeted. Needle steering is a promising technique to overcome this
challenge. In this paper, we describe the development of a novel steering system for an actuated-tip flexible needle. Strain measurements from an array of Fiber Bragg Grating (FBG) sensors are used for… Meer weergeven

Needle insertion procedures are commonly performed in current clinical practice for diagnostic and therapeutic purposes. Although prevailing technology allows accurate localization of lesions, they cannot yet be precisely targeted. Needle steering is a promising technique to overcome this
challenge. In this paper, we describe the development of a novel steering system for an actuated-tip flexible needle. Strain measurements from an array of Fiber Bragg Grating (FBG) sensors are used for online reconstruction of the needle shape in 3D-space. FBG-sensor data is then fused with ultrasound images obtained from a clinically-approved Automated Breast Volume Scanner (ABVS) using an unscented Kalman filter. A new ultrasound-based tracking algorithm is developed for the robust tracking of the needle in biological tissue. Two experimental cases are presented to evaluate the proposed steering system. In the first case, the needle shape is reconstructed using the tracked tip position in ultrasound images and FBG sensor measurements, separately. The reconstructed shape is then compared with the actual 3D needle shape obtained from the ABVS. In the second case, two steering experiments are performed to evaluate the overall system by fusing the FBG sensor data and ultrasound images. Average targeting errors are 1.29±0.41 mm and 1.42±0.72 mm in gelatin phantom and biological tissue, respectively. Minder weergeven

Robot-assisted and ultrasound-guided needle insertion systems assist in achieving high targeting accuracy for different applications. In this paper, we introduce the use of Automated Breast Volume Scanner (ABVS) for scanning different soft tissue phantoms. The ABVS is a commercial ultrasound transducer used for clinical breast scanning. A preoperative scan is performed for three-dimensional (3D) target localization and shape reconstruction. The ultrasound transducer is also adapted to be used… Meer weergeven

Robot-assisted and ultrasound-guided needle insertion systems assist in achieving high targeting accuracy for different applications. In this paper, we introduce the use of Automated Breast Volume Scanner (ABVS) for scanning different soft tissue phantoms. The ABVS is a commercial ultrasound transducer used for clinical breast scanning. A preoperative scan is performed for three-dimensional (3D) target localization and shape reconstruction. The ultrasound transducer is also adapted to be used for tracking the needle tip during steering toward the localized targets. The system uses the tracked needle tip position as a feedback to the needle control algorithm. The bevel-tipped flexible needle is steered under ABVS guidance toward a target while avoiding an obstacle embedded in soft tissue phantom. We present experimental results for 3D reconstruction of different convex and non-convex objects with different sizes. Mean Absolute Distance (MAD) and Dice’s coefficient methods are used to evaluate the 3D shape reconstruction algorithm. The results show that the mean MAD values are 0.30±0.13 mm and 0.34±0.17 mm for convex and non-convex shapes, respectively, while mean Dice values are 0.87±0.06 (convex) and 0.85±0.06 (non-convex). Three experimental cases are performed to validate the steering system. Mean targeting errors of 0.54±0.24, 1.50±0.82 and 1.82±0.40 mm are obtained for steering in gelatin phantom, biological tissue and a human breast phantom, respectively. The achieved targeting errors suggest that our approach is sufficient for targeting lesions of 3 mm radius that can be detected using clinical ultrasound imaging systems. Minder weergeven

Purpose: Percutaneous needle insertion procedures are commonly used for diagnostic and therapeutic purposes. Although current technology allows accurate localization of lesions, they cannot yet be precisely targeted. Lung cancer is the most common cause of cancer-related death, and early detection reduces the mortality rate. Therefore, suspicious lesions are tested for diagnosis by performing needle biopsy.
Methods: In this paper, we have presented a novel computed tomography (CT)-compatible… Meer weergeven

Purpose: Percutaneous needle insertion procedures are commonly used for diagnostic and therapeutic purposes. Although current technology allows accurate localization of lesions, they cannot yet be precisely targeted. Lung cancer is the most common cause of cancer-related death, and early detection reduces the mortality rate. Therefore, suspicious lesions are tested for diagnosis by performing needle biopsy.
Methods: In this paper, we have presented a novel computed tomography (CT)-compatible needle insertion device (NID). The NID is used to steer a flexible needle (ϕ0.55mm) with a bevel at the tip in biological tissue. CT images and an electromagnetic (EM) tracking system are used in two separate scenarios to track the needle tip in three-dimensional space during the procedure. Our system uses a control algorithm to steer the needle through a combination of insertion and minimal number of rotations.
Results: Noise analysis of CT images has demonstrated the compatibility of the device. The results for three experimental cases (case 1: open-loop control, case 2: closed-loop control using EM tracking system and case 3: closed-loop control using CT images) are presented. Each experimental case is performed five times, and average targeting errors are 2.86±1.14, 1.11±0.14 and 1.94±0.63mm for case 1, case 2 and case 3, respectively.
Conclusions: The achieved results show that our device is CT-compatible and it is able to steer a bevel-tipped needle toward a target. We are able to use intermittent CT images and EM tracking data to control the needle path in a closed-loop manner. These results are promising and suggest that it is possible to accurately target the lesions in real clinical procedures in the future. Minder weergeven

In this paper, we present a system capable of automatically steering a bevel-tipped flexible needle under ultrasound guidance toward a physical target while avoiding a physical obstacle embedded in gelatin phantoms and biological tissue with curved surfaces. An ultrasound pre-operative scan is performed for three-dimensional (3D) target localization and shape reconstruction. A controller based on implicit force control is developed to align the transducer with curved surfaces to assure the… Meer weergeven

In this paper, we present a system capable of automatically steering a bevel-tipped flexible needle under ultrasound guidance toward a physical target while avoiding a physical obstacle embedded in gelatin phantoms and biological tissue with curved surfaces. An ultrasound pre-operative scan is performed for three-dimensional (3D) target localization and shape reconstruction. A controller based on implicit force control is developed to align the transducer with curved surfaces to assure the maximum contact area, and thus obtain an image of sufficient quality. We experimentally investigate the effect of needle insertion system parameters such as insertion speed, needle diameter and bevel angle on target motion to adjust the parameters that minimize the target motion during insertion. A fast sampling-based path planner is used to compute and periodically update a feasible path to the target that avoids obstacles. We present experimental results for target reconstruction and needle insertion procedures in gelatin-based phantoms and biological tissue. Mean targeting errors of 1.46 ± 0.37 mm, 1.29 ± 0.29 mm and 1.82 ± 0.58 mm are obtained for phantoms with inclined, curved and combined (inclined and curved) surfaces, respectively, for insertion distance of 86–103 mm. The achieved targeting errors suggest that our approach is sufficient for targeting lesions of 3 mm radius that can be detected using clinical ultrasound imaging systems. Minder weergeven

This study presents the design and control of a CT-compatible needle insertion device. The preliminary experiments prove the design concept. The setup has been used to steer a bevel-tipped nitinol needle of 1mm diameter in a gelatin phantom.

Prostate biopsy and brachytherapy are commonly used for surgical interventions. In this paper, we present a three-dimensional (3D) pre-operative target localization algorithm and a real-time closed-loop control algorithm to robotically steer flexible needles with an asymmetric tip towards a real target in a prostate phantom. The phantom is composed of different tissues including rectal wall, bladder and prostate. The elasticities of these tissues are obtained using an ultrasound-based (acoustic… Meer weergeven

Prostate biopsy and brachytherapy are commonly used for surgical interventions. In this paper, we present a three-dimensional (3D) pre-operative target localization algorithm and a real-time closed-loop control algorithm to robotically steer flexible needles with an asymmetric tip towards a real target in a prostate phantom. The phantom is composed of different tissues including rectal wall, bladder and prostate. The elasticities of these tissues are obtained using an ultrasound-based (acoustic radiation force impulse imaging) technique, and their geometry are obtained using magnetic resonance images. Six experimental cases are performed to evaluate the steering system while inserting the needle into a prostate phantom with different skin thicknesses, insertion angles and surface inclinations. The experimental results show that the target is reached by the needle in all trials. The mean targeting errors between the needle tip and the center of the target embedded in phantoms with 0 mm, 1.5 mm and 2.5 mm skin thicknesses are 1.12 mm, 0.93 mm and 0.49 mm, respectively. The variation of the insertion angle does not have an appreciable affect on the targeting accuracy. The mean targeting error during insertion into a phantom with an inclined surface is 0.85 mm. The results demonstrate the capability of proposed system to robotically steer needles towards a target for interventions in the prostate. Minder weergeven

Minimally invasive surgery assisted by robots is characterized by the restriction of feasible motions of the manipulator link constrained to move through the entry port to the patient’s body. In particular, the link is only allowed to translate along its axis and rotate about the entry point. This requires constraining the manipulator motion with respect to a point known as Remote Center of Motion (RCM). The achievement of any surgical task inside the patient’s body must take into account this… Meer weergeven

Minimally invasive surgery assisted by robots is characterized by the restriction of feasible motions of the manipulator link constrained to move through the entry port to the patient’s body. In particular, the link is only allowed to translate along its axis and rotate about the entry point. This requires constraining the manipulator motion with respect to a point known as Remote Center of Motion (RCM). The achievement of any surgical task inside the patient’s body must take into account this constraint. In this paper we provide a new, general characterization of the RCM constraint useful for task control in the minimally invasive robotic surgery context. To show the effectiveness of our formalization, we consider first a visual task for a manipulator with 6 degrees of freedom holding an endoscopic camera and derive the kinematic control law allowing to achieve the visual task while satisfying the RCM constraint. An example of application of the proposed kinematic modeling to a motion planning problem for a 9 degrees of freedom manipulator with assigned path for the surgical tool is then proposed to illustrate the generality of the approach. Minder weergeven

In the classical image-based visual servoing framework, computation of joint velocities involves the interaction matrix, which depends on current values of 3D parameters of the image features. Typically a rough approximation of these values is used. In this paper we refine a non-linear depth observer for point feature previously developed in our lab, improving it by considering the case of moving targets. The velocity of the target is assumed to be a disturbance to the system, and is estimated… Meer weergeven

In the classical image-based visual servoing framework, computation of joint velocities involves the interaction matrix, which depends on current values of 3D parameters of the image features. Typically a rough approximation of these values is used. In this paper we refine a non-linear depth observer for point feature previously developed in our lab, improving it by considering the case of moving targets. The velocity of the target is assumed to be a disturbance to the system, and is estimated using a disturbance observer. The experimental results with a KUKA KR5 sixx R650 proved that the proposed method improves the convergence rate and reduces the tracking error of a visual servoing task. Minder weergeven