Magnetic Resonance Imaging–Guided Focused Ultrasound Positioning System for Preclinical Studies in Small Animals

Abstract

Objectives A positioning device compatible with magnetic resonance imaging (MRI) used for preclinical studies in small animals was developed that fits in MRI scanners up to 7 T. The positioning device was designed with two computer‐controlled linear stages. Methods The positioning device was evaluated in an agar‐based phantom, which mimics soft tissues, and in a rabbit. Experiments with this positioning device were performed in an MRI system using the agar‐based phantom. The transducer used had a diameter of 50 mm, operated at 0.5 MHz, and focused energy at 60 mm. Results Magnetic resonance thermometry was used to assess the functionality of the device, which showed adequate deposition of thermal energy and sufficient positional accuracy in all axes. Conclusions The proposed system fits in MRI scanners up to 7 T. Because of the size of the positioning device, at the moment, it can be used to perform preclinical studies on small animals such as mice, rats, and rabbits.

Preclinical robotic device for magnetic resonance imaging guided focussed ultrasound

“…Both piezoelectric 28,29,31,34 and pneumatic 30 motors were utilised for actuating motion. So far, our group manufactured numerous MRI‐guided FUS (MRgFUS) systems by 3D printing, which comprise piezoelectric motors and MR compatible optical encoders for precisely actuating and monitoring motion, respectively 31–34 …”

“…So far, our group manufactured numerous MRIguided FUS (MRgFUS) systems by 3D printing, which comprise piezoelectric motors and MR compatible optical encoders for precisely actuating and monitoring motion, respectively. [31][32][33][34] In the current study, we propose an in-house developed robotic device with advanced ergonomics for preclinical studies on MRIguided FUS. The proposed device has compact dimensions, which make it capable for integration with all commercial scanners of cylindrical bore.…”

“…In prior studies, a lot of FUS robotic systems with varying functionalities and intended applications have been proposed. 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 Motion was established through different mechanisms including linear ball, 28 brass racks and pinion, 29 and jackscrew 34 mechanisms. Both piezoelectric 28 , 29 , 31 , 34 and pneumatic 30 motors were utilised for actuating motion.…”

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

“…Through the last years, a series of MRgFUS devices that use piezoelectric motor actuators have been manufactured using rapid prototyping. 23,[25][26][27] These systems comprise MR-compatible optical encoders for accurately monitoring motion. 23,[25][26][27] In this study, a 3 DOF robotic system intended for treating tumours in the abdomen by precisely delivering non-ionizing FUS energy under MRI guidance is presented.…”

“…23,[25][26][27] These systems comprise MR-compatible optical encoders for accurately monitoring motion. 23,[25][26][27] In this study, a 3 DOF robotic system intended for treating tumours in the abdomen by precisely delivering non-ionizing FUS energy under MRI guidance is presented. All the mechanical features were compactly housed in a single enclosure designed to be firmly secured within the MRI couch of conventional MRI scanners.…”