Pascal, Joris
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Tracking of a magnetically navigated millirobot with a magnetic-field camera
A significant progress has been made in the development of magnetic micromanipulation for minimally invasive surgery. The development of systems to localize millimeter-sized robots during magnetic manipulation without line-of-sight detection remains, however, a challenging task. In this study, we focused on the development of a tracking system aiming to fill this gap. A robot, which consists of a cylindrical magnet of 1-mm diameter, is localized using a 2-D array of 3-D magnetoresistive sensors. The system, also called magnetic-field camera (MFC), provides tracking of the robot with a refresh rate of 2 Hz. The developed tracking algorithm reaches a mean absolute error (MAE) for the position and the orientation of, respectively, 0.56 mm and 5.13° in 2-D. This system can be added to the existing magnetic manipulation systems (MMSs) allowing closed-loop control of the navigation. The performances of the MFC are not affected by an exposure to strong magnetic fields. Exposures up to 3 T have been validated. Increasing the integrability of the MFC into MMSs. The presented tracking system makes it possible to target applications, such as minimally invasive eye surgery or drug delivery. The high spatial and magnetic resolutions allow the tracking of magnetic particles, down to 200- μm diameter, when placed close to the surface. The system could also be suitable for the localization of small objects for 2-D biomanipulation.
Towards a new generation of electromagnetic navigation system for deep brain stimulation
Millirobot magnetic manipulation for ocular drug delivery with sub millimeter precision
Significant progress has been made in the development of magnetic micromanipulation for minimally invasive surgery. The development of systems to localize millimetric size robots during magnetic navigation and without line of sight remains however a challenging task. In this study, we focused on the development of a tracking system aiming to fill this gap. A robot which consists of a cylindrical magnet of 1 mm diameter is localized using a 2D array of 3D magneto resistive sensors. The system provides a tracking of the robot with a refreshing rate of 2 Hz. The developed tracking algorithm reaches a mean absolute error for the position and the orientation of, respectively 0.56 mm and 5.13° in 2D. This system can be added to existing magnetic navigation systems allowing closed loop control of the navigation. The presented tracking system makes it possible to target applications such as minimally invasive ocular drug delivery.
Tracking the orientation of deep brain stimulation electrodes using an embedded magnetic sensor
This paper proposes a three-dimensional (3D) orientation tracking method of a 3D magnetic sensor embedded in a 2.5 mm diameter electrode. Our system aims to be used during intraoperative surgery to detect the orientation of directional leads (D-leads) for deep brain stimulation (DBS).
Magnetic field interactions of smartwatches and portable electronic devices with CIEDs. Did we open a Pandora’s box?
Magnetic interaction of portable electronic devices (PEDs), such as state-of-the art mobile phones, with cardiovascular implantable electronic devices (CIEDs) has been reported. The aim of the study was to quantify the magnetic fields of latest generation smartwatches and other PEDs and to evaluate and predict their risk of CIED interactions.
Towards tracking of deep brain stimulation electrodes using an integrated magnetometer
This paper presents a tracking system using magnetometers, possibly integrable in a deep brain stimulation (DBS) electrode. DBS is a treatment for movement disorders where the position of the implant is of prime importance. Positioning challenges during the surgery could be addressed thanks to a magnetic tracking. The system proposed in this paper, complementary to existing procedures, has been designed to bridge preoperative clinical imaging with DBS surgery, allowing the surgeon to increase his/her control on the implantation trajectory. Here the magnetic source required for tracking consists of three coils, and is experimentally mapped. This mapping has been performed with an in-house three-dimensional magnetic camera. The system demonstrates how magnetometers integrated directly at the tip of a DBS electrode, might improve treatment by monitoring the position during and after the surgery. The three-dimensional operation without line of sight has been demonstrated using a reference obtained with magnetic resonance imaging (MRI) of a simplified brain model. We observed experimentally a mean absolute error of 1.35 mm and an Euclidean error of 3.07 mm. Several areas of improvement to target errors below 1 mm are also discussed.
Experimental assessment of the performances of an anisotropic magnetoresistive sensor after exposure to strong magnetic fields
On-chip magnetometers are already integrated within long-term implants such as cardiac implantable electronic devices. They are also good candidates to be integrated within the next generations of brain stimulation electrodes to provide their position and orientation. In all cases, long-term implants are expected to be at least certified as MRI conditional. We investigated the resilience to the exposure to 3 T and 7 T of an anisotropic magnetoresistive sensor integrating a set/reset function. The sensitivity, non-linearity, and offset of a batch of 63 identical sensors were not affected by the exposure. These preliminary results provide new insights on the usability of magnetoresistive sensors for biomedical applications requiring MRI conditionality.
A magnetic camera to assess the risk of magnetic interaction between portable electronics and cardiac implantable electronic devices
Towards tracking of deep brain stimulation electrodes using an integrated magnetometer
This paper presents a tracking system using magnetometers, possibly integrable in a deep brain stimulation (DBS) electrode. DBS is a treatment for movement disorders where the position of the implant is of prime importance. Positioning challenges during the surgery could be addressed thanks to a magnetic tracking. The system proposed in this paper, complementary to existing procedures, has been designed to bridge preoperative clinical imaging with DBS surgery, allowing the surgeon to increase his/her control on the implantation trajectory. Here the magnetic source required for tracking consists of three coils, and is experimentally mapped. This mapping has been performed with an in-house three-dimensional magnetic camera. The system demonstrates how magnetometers integrated directly at the tip of a DBS electrode, might improve treatment by monitoring the position during and after the surgery. The three-dimensional operation without line of sight has been demonstrated using a reference obtained with magnetic resonance imaging (MRI) of a simplified brain model. We observed experimentally a mean absolute error of 1.35 mm and an Euclidean error of 3.07 mm. Several areas of improvement to target errors below 1 mm are also discussed.