Feasibility of Ultrasonic Heating through Skull Phantom Using Single-element Transducer.

Background: Noninvasive neurosurgery has become possible through the use of transcranial focused ultrasound (FUS). This study assessed the heating ability of single element spherically focused transducers operating at 0.4 and 1.1 MHz through three-dimensional (3D) printed thermoplastic skull phantoms. Methods: Phantoms with precise skull bone geometry of a male patient were 3D printed using common thermoplastic materials following segmentation on a computed tomography head scan image. The brain tissue was mimicked by an agar-based gel phantom developed in-house. The selection of phantom materials was mainly based on transmission-through attenuation measurements. Phantom sonications were performed through water, and then, with the skull phantoms intervening the beam path. In each case, thermometry was performed at the focal spot using thermocouples. Results: The focal temperature change in the presence of the skull phantoms was reduced to less than 20 % of that recorded in free field when using the 0.4 MHz transducer, whereas the 1.1 MHz trans-skull sonication produced minimal or no change in focal temperature. The 0.4 MHz transducer showed better performance in trans-skull transmission but still not efficient. Conclusion: The inability of both tested single element transducers to steer the beam through the high attenuating skull phantoms and raise the temperature at the focus was confirmed, underlying the necessity to use a correction technique to compensate for energy losses, such those provided by phased arrays. The proposed phantom could be used as a cost-effective and ergonomic tool for trans-skull FUS preclinical studies.

High-quality Agar and Polyacrylamide Tumor-mimicking Phantom Models for Magnetic Resonance-guided Focused Ultrasound Applications.

Background: Tissue-mimicking phantoms (TMPs) have been used extensively in clinical and nonclinical settings to simulate the thermal effects of focus ultrasound (FUS) technology in real tissue or organs. With recent technological developments in the FUS technology and its monitoring/guided techniques such as ultrasound-guided FUS and magnetic resonance-guided FUS (MRgFUS) the need for TMPs are more important than ever to ensure the safety of the patients before being treated with FUS for a variety of diseases (e.g., cancer or neurological). The purpose of this study was to prepare a tumor-mimicking phantom (TUMP) model that can simulate competently a tumor that is surrounded by healthy tissue. Methods: The TUMP models were prepared using polyacrylamide (PAA) and agar solutions enriched with MR contrast agents (silicon dioxide and glycerol), and the thermosensitive component bovine serum albumin (BSA) that can alter its physical properties once thermal change is detected, therefore offering real-time visualization of the applied FUS ablation in the TUMPs models. To establish if these TUMPs are good candidates to be used in thermoablation, their thermal properties were characterized with a custom-made FUS system in the laboratory and a magnetic resonance imaging (MRI) setup with MR-thermometry. The BSA protein's coagulation temperature was adjusted at 55°C by setting the pH of the PAA solution to 4.5, therefore simulating the necrosis temperature of the tissue. Results: The experiments carried out showed that the TUMP models prepared by PAA can change color from transparent to cream-white due to the BSA protein coagulation caused by the thermal stress applied. The TUMP models offered a good MRI contrast between the TMPs and the TUMPs including real-time visualization of the ablation area due to the BSA protein coagulation. Furthermore, the T2-weighted MR images obtained showed a significant change in T2 when the BSA protein is thermally coagulated. MR thermometry maps demonstrated that the suggested TUMP models may successfully imitate a tumor that is present in soft tissue. Conclusion: The TUMP models developed in this study have numerous uses in the testing and calibration of FUS equipment including the simulation and validation of thermal therapy treatment plans with FUS or MRgFUS in oncology applications.

An in vitro Model for Experimental Evaluation of Sonothrombolysis under Tissue-mimicking Material Conditions.

Background: The mechanical properties of therapeutic ultrasound (US) have attracted scientific interest for thrombolysis enhancement in combination with thrombolytic agents and microbubbles (MBs). The aim of the study was to develop an in vitro model to observe how the effects of sonothrombolysis change in the case where a tissue-mimicking material (TMM) is placed in the path of the US beam before the clot. Methods: Fully retracted blood clots were prepared and pulse sonicated for 1 h under various conditions. The system was in a state of real circulating flow with a branch of an open bypass and an occluded tube containing a blood clot, thus mimicking the case of ischemic stroke. The effectiveness of thrombolysis was quantified in milligrams of clots removed. An agar-based TMM was developed around the occluded tube. Results: The clot breakdown in a TMM was found to be more pronounced than in water, presumably due to the retention of the acoustic field. A higher level of acoustic power was required to initiate clot lysis (>76 W acoustic power) using only focused US (FUS). The greatest thrombolysis enhancement was observed with the largest chosen pulse duration (PD) and the use of MBs (150 mg clot mass lysis). The synergistic effect of FUS in combination with MBs on the enzymatic fibrinolysis enhanced thrombolysis efficacy by 260% compared to thrombolysis induced using only FUS. A reduction in the degree of clot lysis was detected due to the attenuation factor of the intervening material (30 mg at 1 and 4 ms PD). Conclusion: In vitro thrombolytic models including a TMM can provide a more realistic evaluation of new thrombolytic protocols. However, higher acoustic power should be considered to compensate for the attenuation factor. The rate of clot lysis is slow and the clinical use of this method will be challenging.

MR relaxation times of agar-based tissue-mimicking phantoms.

Agar gels were previously proven capable of accurately replicating the acoustical and thermal properties of real tissue and widely used for the construction of tissue-mimicking phantoms (TMPs) for focused ultrasound (FUS) applications. Given the current popularity of magnetic resonance-guided FUS (MRgFUS), we have investigated the MR relaxation times T1 and T2 of different mixtures of agar-based phantoms. Nine TMPs were constructed containing agar as the gelling agent and various concentrations of silicon dioxide and evaporated milk. An agar-based phantom doped with wood powder was also evaluated. A series of MR images were acquired in a 1.5 T scanner for T1 and T2 mapping. T2 was predominantly affected by varying agar concentrations. A trend toward decreasing T1 with an increasing concentration of evaporated milk was observed. The addition of silicon dioxide decreased both relaxation times of pure agar gels. The proposed phantoms have great potential for use with the continuously emerging MRgFUS technology. The MR relaxation times of several body tissues can be mimicked by adjusting the concentration of ingredients, thus enabling more accurate and realistic MRgFUS studies.

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

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.

Acoustical properties of 3D printed thermoplastics.

With focused ultrasound (FUS) gaining popularity as a therapeutic modality for brain diseases, the need for skull phantoms that are suitable for evaluating FUS protocols is increasing. In the current study, the acoustical properties of several three-dimensional (3D) printed thermoplastic samples were evaluated to assess their suitability to mimic human skull and bone accurately. Samples were 3D printed using eight commercially available thermoplastic materials. The acoustic properties of the printed samples, including attenuation coefficient, speed of sound, and acoustic impedance, were investigated using transmission-through and pulse-echo techniques. The ultrasonic attenuation, estimated at a frequency of 1.1 MHz, varied from approximately 7 to 32 dB/cm. The frequency dependence of attenuation was described by a power law in the frequency range of 0.2-3.5 MHz, and the exponential index of frequency was found to vary from 1.30 to 2.24. The longitudinal velocity of 2.7 MHz sound waves was in the range of 1700-3050 m/s. The results demonstrate that thermoplastics could potentially be used for the 3D construction of high-quality skull phantoms.

A High Intensity Focused Ultrasound System for Veterinary Oncology Applications.

BACKGROUND: Magnetic resonance-guided focused ultrasound surgery is an incisionless energy-based thermal method that is used for ablating tumors in the veterinary clinic. AIMS AND OBJECTIVES: In this article we describe a prototype of a veterinary system compatible with magnetic resonance imaging intended for small-to-medium-sized companion animals that was developed and tested in vivo in adult rabbits. METHODS: Real-time monitoring of the ablation during the experiment was possible with MR thermometry. Experiments involved thermal monitoring of sonications applied in the thigh of the rabbits. A 38-mm diameter transducer operating at 2.6 MHz was used with a 60-mm-focal length. The robotic system employed 3 linear axes and one angular axis. For this study, only X and Y axis were enabled. Due to the target size limitations, motion in Z and Θ was not needed. The functionality of the positioning device was evaluated by means of MR thermometry, demonstrating sufficient heating and accurate motion in both axes of operation. RESULTS: The postmortem findings confirm the ability of the system to induce thermal ablations in vivo in the absence of adverse effects. CONCLUSIONS: The device is a reliable and affordable solution for companion animal hospitals, offering and additional tool for the veterinary oncology society.

Ultrasonic Attenuation of an Agar, Silicon Dioxide, and Evaporated Milk Gel Phantom.

BACKGROUND: It has been demonstrated that agar-based gel phantoms can emulate the acoustic parameters of real tissues and are the most commonly used tissue-mimicking materials for high-intensity focused ultrasound applications. The following study presents ultrasonic attenuation measurements of agar-based phantoms with different concentrations of additives (percent of agar, silicon dioxide and evaporated milk) in an effort of matching the material's acoustic property as close as possible to human tissues. METHODS: Nine different agar-based phantoms with various amounts of agar, silicon dioxide, and evaporated milk were prepared. Attenuation measurements of the samples were conducted using the through-transmission immersion techniques. RESULTS: The ultrasonic attenuation coefficient of the agar-based phantoms varied in the range of 0.30-1.49 dB/cm-MHz. The attenuation was found to increase in proportion to the concentration of agar and evaporated milk. Silicon dioxide was found to significantly contribute to the attenuation coefficient up to 4% weight to volume (w/v) concentration. CONCLUSION: The acoustic attenuation coefficient of agar-based phantoms can be adjusted according to the tissue of interest in the range of animal and human tissues by the proper selection of agar, silicon dioxide, and evaporated milk.

Amyloid ß Plaque Reduction With Antibodies Crossing the Blood-Brain Barrier, Which Was Opened in 3 Sessions of Focused Ultrasound in a Rabbit Model.

OBJECTIVES: The main objective of this study was to remove amyloid ß plaques by applying multiple sessions of focused ultrasound (US)-induced blood-brain barrier (BBB) opening using microbubbles with and without delivery of antibodies in a rabbit model. METHODS: The animal model was achieved by feeding a high-cholesterol diet to rabbits for 4 months. Fifty-two New Zealand White rabbits were divided into treatment groups: untreated control, high-cholesterol diet only, antibodies only, focused US only, and focused US and antibodies. Three sessions of focused US were administered to the treatment groups. RESULTS: It was shown that with this animal model, the plaques were 30 µm in diameter. By increasing the number of sessions, the number of plaques decreased (both for focused US only and focused US and antibodies). Without the application of focused US, the average number of plaques dropped from 200/cm2 (before treatment) to 170/cm2 (after treatment). The effect of treatment with focused US with antibodies was more drastic. With 3 BBB opening sessions, the average number of plaques was reduced from 200 to 78/cm2 . CONCLUSIONS: This feasibility study had demonstrated that by opening the BBB, it will be possible to deliver exogenous antibodies to the brain, thus eliminating amyloid ß plaques. More importantly with repeated opening of the BBB (3 times in this study), the reduction in the number of plaques was increased.

Microbubble-Based Sonothrombolysis Using a Planar Rectangular Ultrasonic Transducer.

BACKGROUND: The aim of the proposed study was to evaluate in an in vitro flow model the ability of small planar rectangular (2 × 10 mm2) ultrasonic transducer to enhance thrombolysis induced by the thrombolytic agent tenecteplase (TNK-tPA). METHODS: To provide a more realistic clinical environment of stroke, the study was conducted under realistic flow conditions and TNK-tPA concentrations. Fully retracted porcine blood clots were used to determine the thrombolytic efficacy of ultrasound (US) waves as an adjunct to TNK-tPA or in combination with microbubbles (MBs). Two ultrasonic flat rectangular transducers were used in the experiments, operating at 3.7 and 5.2 MHz respectively. A pulsed US protocol that maintained temperature elevation at the target of 1°C was applied. Thrombolysis efficacy was measured in milligrams of mass clot removed. RESULTS: The effect of experimental parameters, such as power, frequency, and MBs administration, on thrombolysis efficacy was explored. CONCLUSIONS: The results revealed that thrombolysis efficacy decreases at higher frequency, and therefore, the possibility of using lower frequency to improve efficacy should be further investigated. Additionally, study findings demonstrated that the combination of 3.7 MHz with MBs as an adjunct to TNK-tPA strongly enhanced thrombolysis efficacy, because with 30 minutes of treatment, 700 mg of clot was removed through nonthermal mechanisms. As a final point, this study has shown that MBs dose influences thrombolysis enhancement, because higher thrombolytic efficacy was observed with higher doses of MBs.

Review of Protocols Used in Ultrasound Thrombolysis.

OBJECTIVES: This paper focuses on the review of protocols used in thrombolysis studies with ultrasound. MATERIALS AND METHODS: Data from peer-review articles were acquired. RESULTS: The protocols of several published reports are summarized in 3 tables (in vitro, in vivo, and clinical), providing detailed information concerning clot model, thrombolytic drug, treatment mode, sonication parameters, evaluation method, thrombolysis outcome, side effects, and conclusions. CONCLUSIONS: The aim of this review was to give an overview of the different protocols used so far in the field of sonothrombolysis and investigate the impact of several aspects involved on sonothrombolysis outcome.

In Vitro Evaluation of Focused Ultrasound-Enhanced TNK-Tissue Plasminogen Activator-Mediated Thrombolysis.

INTRODUCTION: The low and incomplete recanalization performance of thrombolytic therapy in patients with acute ischemic stroke has created the need to use focused ultrasound (FUS) energy as a way to enhance thrombolysis efficiency (sonothrombolysis). Using an in vitro flow model, the role of various parameters involved in FUS-enhanced tenecteplase (TNK-tPA [tissue plasminogen activator])-mediated thrombolysis was evaluated. MATERIALS AND METHODS: Fully retracted porcine blood clots were used for the proposed parametric studies. A spherically FUS transducer (4 cm diameter), focusing at 10 cm and operating at 1 MHz, was used. Pulsed ultrasound protocols were applied that maintained temperature elevation at the focus that never exceeded 1°C. Thrombolysis efficiency was measured as the relative reduction in the mass of the clot. RESULTS: The role of various properties on thrombolysis efficacy was examined. These various properties are the acoustic power, the TNK-tPA concentration, the flow rate, the exposure time, the pulse length, the pulse repetition frequency, the duty factor, the formation of standing waves, the acoustic medium, and the administration of microbubbles. Study results have demonstrated that the parameters examined influenced thrombolysis efficacy and the degree of thrombolysis achieved by each parameter was measured. CONCLUSIONS: Study findings helped us to optimize the treatment protocol for 1 MHz pulsed FUS that maximizes the thrombolytic efficacy of TNK-tPA, which potentially could be applied for therapeutic purposes. The outcome of the study showed poor thrombolysis efficacy, as with 30 minutes of FUS treatment only 370 mg of clot was removed.

The Enhancing Effect of Focused Ultrasound on TNK-Tissue Plasminogen Activator-Induced Thrombolysis Using an In Vitro Circulating Flow Model.

BACKGROUND: The limited efficacy of thrombolytic therapy in patients with ischemic stroke has created the need to use focused ultrasound (FUS) energy as a way to enhance thrombolysis efficacy (sonothrombolysis). Using an in vitro circulating flow model, we evaluated the role of physical parameters on tenecteplase (TNK-tPA)-mediated thrombolysis. MATERIALS AND METHODS: Fully retracted porcine blood clots were used for the proposed experimental study. To provide a more realistic clinical environment of stroke, the study was conducted under realistic flow conditions and TNK-tPA concentrations. Two spherically FUS transducers (4-cm diameter), focusing at 10 cm and operating at .6 and 1.05 MHz, respectively, were used. Pulsed ultrasound protocols that maintained a localized temperature elevation at the focus of 1°C were applied. Thrombolysis efficacy was measured in milligram of mass clot removed. RESULTS: The effect of physical parameters such as temperature, FUS frequency, acoustic power (AP), FUS energy, and microbubble (MB) administration on thrombolysis efficacy was examined. CONCLUSIONS: Study findings established that higher FUS frequencies (1 MHz) are associated with enhanced thrombolysis compared to lower FUS frequencies (.6 MHz). Furthermore, an increase in the linear relationship between AP and thrombolysis efficacy was exhibited. Also, the outcome of the study showed that the combination of 1-MHz FUS pulses with MBs strongly enhanced the enzymatic thrombolytic efficacy of TNK-tPA, because with 30 minutes of treatment, 1050 mg of clot was removed through nonthermal mechanisms. Taking into consideration that stroke is time dependent, this thrombolytic rate should be sufficient for timely recanalization of the occluded cerebral artery.

In Vitro and In Vivo evaluation of a magnetic resonance imaging-guided focused ultrasound system for dissolving clots in combination with thrombolytic drugs.

BACKGROUND: The potential of a magnetic resonance imaging (MRI)-guided focused ultrasound (MRgFUS) system combined with thrombolytic drugs to dissolve clots is investigated using in vitro and in vivo models. METHODS: Two spherically focused transducers of 5 cm diameter focusing at 10 cm and operating at either .5 or 1 MHz were used. Doppler ultrasound was used to measure the blood flow during the in vivo experiments. RESULTS: The effect of ultrasound intensity, transducer beam area, and frequency on the dissolved volume was investigated. The goal was to maintain a temperature increase of less than 1°C (called safe temperature) at the clot during the application of pulsed ultrasound and at the same time achieve efficient thrombolysis. CONCLUSIONS: The MRgFUS technique was proven successful in dissolving clots in vitro and in vivo. It was found that the volume of dissolved clot increases with acoustic intensity and beam size and decreases with frequency. With this system, it was possible to push ultrasound through a plastic phantom skull using a .5 MHz transducer. The beam of ultrasound through the phantom skull was monitored using the MRI technique of fast spoiled gradient. Finally, the thrombus in the in vivo model (ear artery) was successfully destroyed with the therapeutic protocols investigated in the in vitro models. This study shows that FUS using a single element MR-compatible transducer has the potential to treat clots in synergy with thrombolytic drugs. More advanced MRgFUS systems, such as phased arrays, will have a greater impact in sonothrombolysis.

MRI-guided sonothrombolysis of rabbit carotid artery.

The potential of magnetic resonance imaging-guided focused ultrasound (MRgFUS) combined with the thrombolytic drug recombinant tissue plasminogen activator (rt-PA) to dissolve clots in the carotid of a New Zealand rabbit in vivo is evaluated. A spherically focused transducer of 5-cm diameter, focusing at 10 cm and operating at 1 MHz, was used. A pulsed ultrasound protocol was used that maintains a tissue temperature increase of less than 1 °C in the clot (called safe temperature). MRgFUS has the potentials to dissolve clots that are injected in the carotid of rabbits in vivo. It was found that the time needed for opening the carotid artery using ultrasound and rt-PA was decreased compared with just using rt-PA. The time needed for opening the artery decreases with increasing acoustic intensity. With an intensity of 20 W/cm2 (spatial average temporal average), which is not causing artery heating, the time needed to completely open the artery was 70 minutes. The proposed protocol was monitored using magnetic resonance angiography every 1 minute.

MRI compatibility testing of commercial high intensity focused ultrasound transducers.

PURPOSE: The study aimed to compare the performance of eight commercially available single-element High Intensity Focused Ultrasound (HIFU) transducers in terms of Magnetic Resonance Imaging (MRI) compatibility. METHODS: Imaging of an agar-based MRI phantom was performed in a 3 T MRI scanner utilizing T2-Weighted Fast Spin Echo (FSE) and Fast low angle shot (FLASH) sequences, which are typically employed for high resolution anatomical imaging and thermometry, respectively. Reference magnitude and phase images of the phantom were compared with images acquired in the presence of each transducer in terms of the signal to noise ratio (SNR), introduced artifacts, and overall image quality. RESULTS: The degree of observed artifacts highly differed among the various transducers. The transducer whose backing material included magnetic impurities showed poor performance in the MRI, introducing significant susceptibility artifacts such as geometric distortions and signal void bands. Additionally, it caused the most significant SNR drop. Other transducers were shown to exhibit high level of MRI compatibility as the resulting images closely resembled the reference images with minimal to no apparent artifacts and comparable SNR values. CONCLUSIONS: The study findings may facilitate researchers to select the most suitable transducer for their research, simultaneously avoiding unnecessary testing. The study further provides useful design considerations for MRI compatible transducers.

Simple, inexpensive, and ergonomic phantom for quality assurance control of MRI guided Focused Ultrasound systems.

PURPOSE: The popularity of Magnetic Resonance guided Focused Ultrasound (MRgFUS) as a beneficial therapeutic solution for many diseases is increasing rapidly, thus raising the need for reliable quality assurance (QA) phantoms for routine testing of MRgFUS systems. In this study, we propose a thin acrylic film as the cheapest and most easily accessible phantom for assessing the functionality of MRgFUS hardware and software. METHODS: Through the paper, specific QA tests are detailed in the framework of evaluating an MRgFUS preclinical robotic device comprising a single element spherically focused transducer with a nominal frequency of 2.75 MHz. These tests take advantage of the reflection of ultrasonic waves at a plastic-air interface, which results in almost immediate lesion formation on the film at a threshold of applied acoustic energy. RESULTS: The phantom offered qualitative information on the power field distribution of the FUS transducer and the ability to visualize different FUS protocols. It also enabled quick and reliable assessment of various navigation algorithms as they are used in real treatments, and also allowed for the assessment of the accuracy of robotic motion. CONCLUSION: Therefore, it could serve as a useful tool for detecting defects in system's performance over its lifetime after establishing a baseline while concurrently contributing to establish QA and calibration guidelines for clinical routine controls.

Evaluating acoustic and thermal properties of a plaque phantom.

PURPOSE: The aim of this study is to evaluate the acoustic and thermal properties of a plaque phantom. This is very important for the effective implementation of ultrasound not only in diagnosis but especially in treatment for the future. MATERIAL AND METHODS: An evaluation of acoustic and thermal properties of plaque phantoms to test their suitability mainly for ultrasound imaging and therapy was presented. The evaluation included measurements of the acoustic propagation speed using pulse-echo technique, ultrasonic attenuation coefficient using through transmission immersion technique, and absorption coefficient. Moreover, thermal properties (thermal conductivity, volumetric specific heat capacity and thermal diffusivity) were measured with the transient method using a needle probe. RESULTS: It was shown that acoustic and thermal properties of atherosclerotic plaque phantoms fall well within the range of reported values for atherosclerotic plaque and slightly different for thermal diffusivity and volumetric specific heat capacity for soft tissues. The mean value of acoustic and thermal properties and their standard deviation of plaque phantoms were 1523 ± 23 m/s for acoustic speed, 0.50 ± 0.02 W/mK for thermal conductivity, 0.30 ± 0.21 db/cm-MHz for ultrasonic absorption coefficient and 1.63 ± 0.46 db/cm-MHz for ultrasonic attenuation coefficient. CONCLUSIONS: This study demonstrated that acoustic and thermal properties of atherosclerotic plaque phantoms were within the range of reported values. Future studies should be focused on the optimum recipe of the atherosclerotic plaque phantoms that mimics the human atherosclerotic plaque (agar 4% w/v, gypsum 10% w/v and butter 10% w/v) and can be used for HIFU therapy.

Preclinical robotic device for magnetic resonance imaging guided focussed ultrasound.

BACKGROUND: A robotic device featuring three motion axes was manufactured for preclinical research on focussed ultrasound (FUS). The device comprises a 2.75 MHz single element ultrasonic transducer and is guided by Magnetic Resonance Imaging (MRI). METHODS: The compatibility of the device with the MRI was evaluated by estimating the influence on the signal-to-noise ratio (SNR). The efficacy of the transducer in generating ablative temperatures was evaluated in phantoms and excised porcine tissue. RESULTS: System's activation in the MRI scanner reduced the SNR to an acceptable level without compromising the image quality. The transducer demonstrated efficient heating ability as proved by MR thermometry. Discrete and overlapping thermal lesions were inflicted in excised tissue. CONCLUSIONS: The FUS system was proven effective for FUS thermal applications in the MRI setting. It can thus be used for multiple preclinical applications of the emerging MRI-guided FUS technology. The device can be scaled-up for human use with minor modifications.