Robotic system for magnetic resonance guided focused ultrasound ablation of abdominal cancer

Abstract

Background: A prototype robotic system that uses magnetic resonance guided focused ultrasound (MRgFUS) technology is presented. It features three degrees of freedom (DOF) and is intended for thermal ablation of abdominal cancer. Methods:The device is equipped with three identical transducers being offset between them, thus focussing at different depths in tissue. The efficacy and safety of the system in ablating rabbit liver and kidney was assessed, both in laboratory and magnetic resonance imaging (MRI) conditions.Results: Despite these organs' challenging location, in situ coagulative necrosis of a tissue area was achieved. Heating of abdominal organs in rabbit was successfully monitored with MR thermometry. Conclusions:The MRgFUS system was proven successful in creating lesions in the abdominal area of rabbits. The outcomes of the study are promising for future translation of the technology to the clinic.

Full coverage path planning algorithm for MRgFUS therapy

“…31 Such simplified motion algorithms were widely used in order to test the functionality of MRgFUS robotic devices in creating discrete and overlapping lesions, specifically by performing multiple ablations in line and square grid patterns in gel TMPs and animal tissue. 15,[32][33][34][35][36] In the current version, the software can be interfaced with the Follow up studies will test the performance of the developed software in ex-vivo and in vivo animal tissue where thermal diffusion phenomena are more likely to affect lesion formation. This will enable better assessment of the performance of the Zig Zag pattern and will provide insights on the sonication protocol for safe in vivo studies.…”

“…Advantageously, the developed algorithm enabled accurate path planning for full coverage of segmented ROIs of any shape, whereas the previous version allowed just for automating motion in XY rectangular grids 31 . Such simplified motion algorithms were widely used in order to test the functionality of MRgFUS robotic devices in creating discrete and overlapping lesions, specifically by performing multiple ablations in line and square grid patterns in gel TMPs and animal tissue 15,32–36 …”

Robotic system for top to bottom MRgFUS therapy of multiple cancer types

“…A smooth and accurate rotation is established through a series of speed reduction gears that amplifies the motors' torque. It is noted that the robotic system has a motion accuracy level comparable to previous versions 21–23 since it follows a similar principle of motion, according to simple accuracy assessment methods 24 …”

“…In this regard, the proposed system aiming to fully exploit the unique benefits of MRI guidance is superior to commercial devices that use US guidance. [10][11][12][13][14] Furthermore, although previously proposed systems [21][22][23][25][26][27][28] can also operate in the MRI setting and could potentially be used for similar applications, more advances in terms of design and functionalities have seen the production of the one proposed herein.…”

“…Firstly, devices dedicated to be cited on the MRI table 21,[25][26][27] occupy valuable space in the scanner while in some cases, the moving parts are being actuated in close proximity to the patient, possibly compromising the safety of the procedure. Other proposed devices 22,23 are characterized by a simplistic design with all the mechanical and ultrasonic components being installed in a compact housing that is incorporated into the patient's bed. The main limitation of this configuration is that it forces the patient in the prone position, whereas the current system allows comfortable supine positioning.…”