35 research outputs found
Automatic Search for Photoacoustic Marker Using Automated Transrectal Ultrasound
Real-time transrectal ultrasound (TRUS) image guidance during robot-assisted
laparoscopic radical prostatectomy has the potential to enhance surgery
outcomes. Whether conventional or photoacoustic TRUS is used, the robotic
system and the TRUS must be registered to each other. Accurate registration can
be performed using photoacoustic (PA markers). However, this requires a manual
search by an assistant [19]. This paper introduces the first automatic search
for PA markers using a transrectal ultrasound robot. This effectively reduces
the challenges associated with the da Vinci-TRUS registration. This paper
investigated the performance of three search algorithms in simulation and
experiment: Weighted Average (WA), Golden Section Search (GSS), and Ternary
Search (TS). For validation, a surgical prostate scenario was mimicked and
various ex vivo tissues were tested. As a result, the WA algorithm can achieve
0.53 degree average error after 9 data acquisitions, while the TS and GSS
algorithm can achieve 0.29 degree and 0.48 degree average errors after 28 data
acquisitions.Comment: 13 pages, 9 figure
Arc-to-line frame registration method for ultrasound and photoacoustic image-guided intraoperative robot-assisted laparoscopic prostatectomy
Purpose: To achieve effective robot-assisted laparoscopic prostatectomy, the
integration of transrectal ultrasound (TRUS) imaging system which is the most
widely used imaging modelity in prostate imaging is essential. However, manual
manipulation of the ultrasound transducer during the procedure will
significantly interfere with the surgery. Therefore, we propose an image
co-registration algorithm based on a photoacoustic marker method, where the
ultrasound / photoacoustic (US/PA) images can be registered to the endoscopic
camera images to ultimately enable the TRUS transducer to automatically track
the surgical instrument Methods: An optimization-based algorithm is proposed to
co-register the images from the two different imaging modalities. The
principles of light propagation and an uncertainty in PM detection were assumed
in this algorithm to improve the stability and accuracy of the algorithm. The
algorithm is validated using the previously developed US/PA image-guided system
with a da Vinci surgical robot. Results: The target-registration-error (TRE) is
measured to evaluate the proposed algorithm. In both simulation and
experimental demonstration, the proposed algorithm achieved a sub-centimeter
accuracy which is acceptable in practical clinics. The result is also
comparable with our previous approach, and the proposed method can be
implemented with a normal white light stereo camera and doesn't require highly
accurate localization of the PM. Conclusion: The proposed frame registration
algorithm enabled a simple yet efficient integration of commercial US/PA
imaging system into laparoscopic surgical setting by leveraging the
characteristic properties of acoustic wave propagation and laser excitation,
contributing to automated US/PA image-guided surgical intervention
applications.Comment: 12 pages, 9 figure
Haptic interface control-design issues and experiments with a planar device
Describes the haptic rendering of a virtual environment by drawing upon concepts developed in the area of teleoperation. A four-channel teleoperation architecture is shown to be an effective means of coordinating the control of a 3-DOF haptic interface with the simulation of a virtual dynamic environmen
An Experimental Investigation of Film Cooling Heat Transfer Coefficients Using the Mass/Heat Analogy
A User Interface for Robot-Assisted Diagnostic Ultrasound
A robot-assisted system for medical diagnostic ultrasound has been developed by the authors. This paper presents key features of the user interface used in this system. While the ultrasound transducer is positioned by a robot, the operator, the robot controller, and an ultrasound image processor have shared control over its motion. Ultrasound image features that can be selected by the operator are recognized and tracked by a variety of techniques. Based on feature tracking, ultrasound image servoing in three axes has been incorporated in the interface and can be enabled to automatically compensate, through robot motions, unwanted motions in the plane of the ultrasound beam. The stability and accuracy of the system is illustrated through a 3D reconstruction of an ultrasound phantom
Haptic Interaction within a Planar Environment
A haptic simulation environment to simulate planar threedegree -of-freedom motion has been developed by the authors. The system consists of a novel parallel manipulandum and associated control, collision detection and dynamic simulation software running on a QNX PC. This paper describes haptic interfacecontrol and outlines the control systems that have been designed for the haptic rendering of virtual environments. Virtual environment design and implementation are also discussed. Using the haptic simulation environment that has been developed, a four-channel teleoperationarchitecture is shown to beane#ective means to display a variety of simulated environments and is compared with apopular impedance-based approach
Seed localization in Ultrasound and Registration to C-Arm Fluoroscopy Using Matched Needle Tracks for Prostate Brachytherapy
We propose a novel fiducial-free approach for the registration of C-arm fluoroscopy to 3-D ultrasound images of prostate brachytherapy implants to enable dosimetry. The approach involves the reliable detection of a subset of radioactive seeds from 3-D ultrasound, and the use of needle tracks in both ultrasound and fluoroscopy for registration. Seed detection in ultrasound is achieved through template matching in 3-D radio frequency ultrasound signals, followed by thresholding and spatial filtering. The resulting subset of seeds is registered to the complete reconstruction of the brachytherapy implant from multiple C-arm fluoroscopy views. To compensate for the deformation caused by the ultrasound probe, simulated warping is applied to the seed cloud from fluoroscopy. The magnitude of the applied warping is optimized within the registration process. The registration is performed in two stages. First, the needle track projections from fluoroscopy and ultrasound are matched. Only the seeds in the matched needles are then used as fiducials for point-based registration. We report results from a physical phantom with a realistic implant (average postregistration seed distance of 1.6 +/- 1.2 mm) and from five clinical patient datasets (average error: 2.8 +/- 1.5 mm over 128 detected seeds). We conclude that it is feasible to use RF ultrasound data, template matching, and spatial filtering to detect a reliable subset of brachytherapy seeds from ultrasound to enable registration to fluoroscopy for dosimetry