Browsing by Author "Ahmad, Mirza Awais"

Now showing 1 - 6 of 6

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Development and 3D spatial calibration of a parallel robot for percutaneous needle procedures with 2D ultrasound guidance
(World Scientific, 2017-12-01) Ahmad, Mirza Awais; Orhan, Sabri Orçun; Yıldırım, Mehmet Can; Bebek, Özkan; Mechanical Engineering; BEBEK, Özkan; Ahmad, Mirza Awais; Orhan, Sabri Orçun; Yıldırım, Mehmet Can
Robotic systems are being applied to medical interventions as they increase the operational accuracy. The proposed autonomous and ultrasound guided 5-DOF parallel robot can achieve such accuracy for needle biopsies, which particularly demand precise needle positioning and insertion. In this paper, the robot's mechanical design, system identifications, and the design of its controller are explained. A torque computed controller with gravity compensation and friction models, yielding a 0.678mm RMS position error for the needle tip, was used. A novel method was used for 3D space calibration of the images for detecting the volume of interest in the biopsy procedure by a multipoint crosswire phantom with parallel threads. The calibration technique had a validation RMS error of 0.03mm.
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Development of the calibration scheme and system integration of the Ozyegin biopsy robot (OBR)
(2016-08) Ahmad, Mirza Awais; Bebek, Özkan; Bebek, Özkan; Demiroğlu, Cenk; Barkana, D. E.; Department of Electrical and Electronics Engineering; Ahmad, Mirza Awais
Imaging systems can fail to visualize cancerous tissues for proper diagnosis. Needle based procedures, like biopsies, increase the chances of accurate diagnosis of tumors. These procedures also have applications in minimally invasive treatments and regional anesthesia. In recent years, robotic systems have found their way into medical applications of needle based interventions by increasing the accuracy of these procedures. Precise needle positioning is critical in such medical applications. This thesis presents the architecture of a robotic system designed for human biopsies. The system includes a 5 DoF parallel robot that can be used in Ultrasound (US) guided percutaneous needle interventions. US imaging is used as the visual feedback. The imaging system must be calibrated in 3D space before integrated with the biopsy robot. A novel method for 3D space calibration using a multipoint cross-wire phantom is introduced in this dissertation. The calibration process is improved using wires parallel to the US image plane in order to locate the exact image position in 3D space. Most of the methods fail to consider the errors caused by this intrinsic assumption that the plane exists at the midpoint of the US probe's base, while probe holding fixtures can cause minute offsets leading to positional inaccuracies. The final calibration experiments resulted in accuracy of 0.03 mm RMS error. Details of real time functionality of the robotic system components working with spatial and computational synchronization is also presented. The real-time operation enables the robotic system to perform autonomously. This ability is demonstrated by tracking a moving target with the needle tip motion with an RMS error of 0.23 mm.
Open Access
Özyeğin biopsy robot: system integration architecture and motion compensation of a moving target
(TÜBİTAK, 2018-05-30) Ahmad, Mirza Awais; Bebek, Özkan; Mechanical Engineering; BEBEK, Özkan; Ahmad, Mirza Awais
This paper presents the complete system architecture of a robotic biopsy system for real-time operations. The system has individual functional blocks working simultaneously including a 5 DoF parallel robot, ultrasound (US) imaging machine, two robotic manipulators, and a motion capturing system. Details of the real-time functionality of the robotic system components working with spatial and computational synchronization are presented. This paper also deals with a scenario in which the target tissue is moving due to the breathing of the patient. The motion of the needle tip and the target is tracked using US images as feedback. Two types of control laws for target tracking are discussed: traditional feedback control and an optimal control method. Motion compensation is demonstrated by tracking a moving target with the needle tip motion with an RMS error of 0.25 mm.
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Real-time needle tip localization in 2D ultrasound images for robotic biopsies
(IEEE, 2015) Kaya, Mert; Şenel, Enes; Ahmad, Mirza Awais; Orhan, Orçun; Bebek, Özkan; Mechanical Engineering; BEBEK, Özkan; Kaya, Mert; Şenel, Enes; Ahmad, Mirza Awais; Orhan, Orçun
In this paper, real-time needle tip tracking method using 2D ultrasound (US) images for robotic biopsies is presented. In this method, the needle tip is estimated with the Gabor filter based image processing algorithm, and the estimation noise is reduced with the Kalman filter. This paper also presents the needle tip tracking simulation to test accuracy of the Kalman filter under position misalignments and tissue deformations. In order to execute proposed method in real-time, the bin packing method is used and the processing time is reduced by 56%, without a GPU. The proposed method was tested in four different phantoms and water medium. The accuracy of the needle tip estimation was measured with optical tracking system, and root mean square error (RMS) of the tip position is found to be 1.17 mm. The experiments showed that the algorithm could track the needle tip in real-time.
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Visual tracking of biopsy needles in 2D ultrasound images
(2016) Kaya, Mert; Şenel, Enes; Ahmad, Mirza Awais; Bebek, Özkan; Mechanical Engineering; BEBEK, Özkan; Kaya, Mert; Şenel, Enes; Ahmad, Mirza Awais
Ultrasound (US) is one the most commonly used medical imaging techniques in percutaneous needle procedures. However, US images are inherently noisy and contain excessive number of artifacts. Hence, it is not easy to track the needle tip in the US images during the needle insertions. At this point, image based visual tracking techniques can be used for needle tip tracking. This paper presents a method for visual tracking of biopsy needles in 2D US images using sum of squared differences and sum of conditional variances. Second order Gauss-Newton optimization is used to decrease processing time and make the tracking more robust. The needle template images used in the method are updated with a strategy to prevent needle loss and detection failures during tracking. The paper also explains how to identify needle losses during tracking and how to recover the needle position without using a needle localization algorithm. We demonstrate the precision of the visual needle tip tracking method with experiments under challenging tracking conditions.
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Visual tracking of multiple moving targets in 2D ultrasound guided robotic percutaneous interventions
(IEEE, 2017) Kaya, Mert; Şenel, Enes; Ahmad, Mirza Awais; Bebek, Özkan; Mechanical Engineering; BEBEK, Özkan; Kaya, Mert; Şenel, Enes; Ahmad, Mirza Awais
Percutaneous needle procedures are mostly carried out with the guidance of 2D ultrasound (US) imaging. US images are inherently noisy and their resolutions are low. Hence, target tracking can be challenging. Image based tracking methods can be used to track the needle and the target. This paper proposes visual tracking of multiple moving points, such as biopsy needles and targets, in 2D US images using normalized cross correlation and mutual information similarity functions. Both moving and deformable targets can be tracked. An affine motion model is used for small and moving target tracking and a thin plate spline motion model is used for deformable target tracking. During the tracking, needle and target template images are updated with a template update strategy. Also, tracking outputs of normalized cross correlation and mutual information are fused using the Kalman filter to reduce the tracking error. During the experiments, needle is inserted using a needle insertion robot. 2D US probe is attached to a robotic arm's end effector to servo the probe along the needle insertion path. Proposed needle and target tracking methods were tested with phantoms. Accuracies of the needle tip and moving target tracking methods were measured using an optical tracking system. Experimental results showed that the proposed tracking method could be used to simultaneously track the needle tip and the targets in real-time in 2D US guided percutaneous needle procedures.