MRI Robot for Prostate Focal Laser Ablation: An Ex Vivo Study in Human Prostate

Seifabadi, Reza; Li, Ming; Xu, Sheng; Chen, Yue; Squires, Allison; Negussie, Ayele H.; Bakhutashvili, Ivane; Choyke, Peter L.; Türkbey, İsmail Barış; Tse, Zion Tsz Ho; Wood, Bradford J.

doi:10.3390/jimaging4120140

Cited by 9 publications

(6 citation statements)

References 17 publications

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“…The average error is near the expected tolerable error and is in the range of potential clinical relevance, depending on the need for accuracy. Other systems for improved accuracy of TP biopsies include a grid template with a 3 mm target distance error in a phantom study 22 and a robotics with a 2 mm error in a phantom study 23 , 24 . However, our HoloLens AR system only provides visual guidance, without any hardware or physical constraints.…”

Section: Discussionmentioning

confidence: 99%

“…Other systems for improved accuracy of TP biopsies include a grid template with a 3 mm target distance error in a phantom study 22 and a robotics with a 2 mm error in a phantom study. 23 , 24 However, our HoloLens AR system only provides visual guidance, without any hardware or physical constraints. Conventional manual guidance with US imaging is subject also to volume averaging of the 2D US slice, which may also be in the 3 mm range.…”

Section: Discussionmentioning

confidence: 99%

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HoloLens augmented reality system for transperineal free-hand prostate procedures

Mehralivand

et al. 2023

J. Med. Imag.

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Purpose: An augmented reality (AR) system was developed to facilitate free-hand real-time needle guidance for transperineal prostate (TP) procedures and to overcome the limitations of a traditional guidance grid.Approach: The HoloLens AR system enables the superimposition of annotated anatomy derived from preprocedural volumetric images onto a patient and addresses the most challenging part of free-hand TP procedures by providing real-time needle tip localization and needle depth visualization during insertion. The AR system accuracy, or the image overlay accuracy (n ¼ 56), and needle targeting accuracy (n ¼ 24) were evaluated within a 3D-printed phantom. Three operators each used a planned-path guidance method (n ¼ 4) and free-hand guidance (n ¼ 4) to guide needles into targets in a gel phantom. Placement error was recorded. The feasibility of the system was further evaluated by delivering soft tissue markers into tumors of an anthropomorphic pelvic phantom via the perineum. Results:The image overlay error was 1.29 AE 0.57 mm, and needle targeting error was 2.13 AE 0.52 mm. The planned-path guidance placements showed similar error compared to the free-hand guidance (4.14 AE 1.08 mm versus 4.20 AE 1.08 mm, p ¼ 0.90). The markers were successfully implanted either into or in close proximity to the target lesion.Conclusions: The HoloLens AR system can provide accurate needle guidance for TP interventions. AR support for free-hand lesion targeting is feasible and may provide more flexibility than grid-based methods, due to the real-time 3D and immersive experience during free-hand TP procedures.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

HoloLens augmented reality system for transperineal free-hand prostate procedures

Mehralivand

et al. 2023

J. Med. Imag.

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“…At present, robotic platforms that are able to leverage real-time intra-op MRI guidance together with continuous control of laser beam projection for tumor ablation are rare. Researchers have targeted procedures such as percutaneous ablation of liver cancer (25,26) and prostate cancer (27)(28)(29), alongside neurosurgical procedures (30,31). However, these systems are primarily designed for contact or needle-based ablation wherein the laser tip is inserted through a single-entry point in the skin and directly into target lesions where it remains stationary during the ablation process.…”

Section: Introductionmentioning

confidence: 99%

Soft robotic manipulator for intraoperative MRI-guided transoral laser microsurgery

Fang

Chow

et al. 2021

Sci. Robot.

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Magnetic resonance (MR) imaging (MRI) provides compelling features for the guidance of interventional procedures, including high-contrast soft tissue imaging, detailed visualization of physiological changes, and thermometry. Laser-based tumor ablation stands to benefit greatly from MRI guidance because 3D resection margins alongside thermal distributions can be evaluated in real time to protect critical structures while ensuring adequate resection margins. However, few studies have investigated the use of projection-based lasers like those for transoral laser microsurgery, potentially because dexterous laser steering is required at the ablation site, raising substantial challenges in the confined MRI bore and its strong magnetic field. Here, we propose an MR-safe soft robotic system for MRI-guided transoral laser microsurgery. Owing to its miniature size (Ø12 × 100 mm), inherent compliance, and five degrees of freedom, the soft robot ensures zero electromagnetic interference with MRI and enables safe and dexterous operation within the confined oral and pharyngeal cavities. The laser manipulator is rapidly fabricated with hybrid soft and hard structures and is powered by microvolume (<0.004 milliter) fluid flow to enable laser steering with enhanced stiffness and lowered hysteresis. A learning-based controller accommodates the inherent nonlinear robot actuation, which was validated with laser path–following tests. Submillimeter laser steering accuracy was demonstrated with a mean error < 0.20 mm. MRI compatibility testing demonstrated zero observable image artifacts during robot operation. Ex vivo tissue ablation and a cadaveric head-and-neck trial were carried out under MRI, where we employed MR thermometry to monitor the tissue ablation margin and thermal diffusion intraoperatively.

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“…Image-guided thermal ablations are increasingly employed in minimally invasive treatments in patients with cancer [ 1 , 2 , 3 , 4 ]. In the last decades, a large number of high-intensity focused ultrasound (HIFU) [ 5 , 6 ] devices have been used in oncology to cover a wide range of cancer types, such as prostate [ 7 ], bone metastases [ 8 ], liver [ 9 ], breast [ 10 ], thyroid [ 11 ], uterine fibroids [ 12 , 13 ], liver and pancreas [ 14 ], and brain [ 15 ]; as well as psychiatric disorders [ 16 ] and essential tremor [ 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

A Computational Study on Temperature Variations in MRgFUS Treatments Using PRF Thermometry Techniques and Optical Probes

et al. 2021

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Structural and metabolic imaging are fundamental for diagnosis, treatment and follow-up in oncology. Beyond the well-established diagnostic imaging applications, ultrasounds are currently emerging in the clinical practice as a noninvasive technology for therapy. Indeed, the sound waves can be used to increase the temperature inside the target solid tumors, leading to apoptosis or necrosis of neoplastic tissues. The Magnetic resonance-guided focused ultrasound surgery (MRgFUS) technology represents a valid application of this ultrasound property, mainly used in oncology and neurology. In this paper; patient safety during MRgFUS treatments was investigated by a series of experiments in a tissue-mimicking phantom and performing ex vivo skin samples, to promptly identify unwanted temperature rises. The acquired MR images, used to evaluate the temperature in the treated areas, were analyzed to compare classical proton resonance frequency (PRF) shift techniques and referenceless thermometry methods to accurately assess the temperature variations. We exploited radial basis function (RBF) neural networks for referenceless thermometry and compared the results against interferometric optical fiber measurements. The experimental measurements were obtained using a set of interferometric optical fibers aimed at quantifying temperature variations directly in the sonication areas. The temperature increases during the treatment were not accurately detected by MRI-based referenceless thermometry methods, and more sensitive measurement systems, such as optical fibers, would be required. In-depth studies about these aspects are needed to monitor temperature and improve safety during MRgFUS treatments.

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MRI Robot for Prostate Focal Laser Ablation: An Ex Vivo Study in Human Prostate

Cited by 9 publications

References 17 publications

HoloLens augmented reality system for transperineal free-hand prostate procedures

HoloLens augmented reality system for transperineal free-hand prostate procedures

Soft robotic manipulator for intraoperative MRI-guided transoral laser microsurgery

A Computational Study on Temperature Variations in MRgFUS Treatments Using PRF Thermometry Techniques and Optical Probes

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