Focused Ultrasound Sonications of Tumor Model in Head Phantom under MRI Monitoring: Effect of Skull Obstruction on Focal Heating

Purpose: This study presents the outcomes of a series of magnetic resonance imaging (MRI)-guided focused ultrasound (MRgFUS) sonications performed on an anatomically accurate head phantom with an embedded tumor simulator to evaluate the effectiveness of partial and complete tumor ablation with obstr...

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Main Authors: Anastasia Antoniou, Antreas Chrysanthou, Leonidas Georgiou, Antonis Christofi, Yiannis Roussakis, Cleanthis Ioannides, Kyriakos Spanoudes, Jufeng Zhao, Liyang Yu, Christakis Damianou
Format: Article
Language:English
Published: Wolters Kluwer Medknow Publications 2025-01-01
Series:Journal of Medical Physics
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Online Access:https://journals.lww.com/10.4103/jmp.jmp_177_24
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author Anastasia Antoniou
Antreas Chrysanthou
Leonidas Georgiou
Antonis Christofi
Yiannis Roussakis
Cleanthis Ioannides
Kyriakos Spanoudes
Jufeng Zhao
Liyang Yu
Christakis Damianou
author_facet Anastasia Antoniou
Antreas Chrysanthou
Leonidas Georgiou
Antonis Christofi
Yiannis Roussakis
Cleanthis Ioannides
Kyriakos Spanoudes
Jufeng Zhao
Liyang Yu
Christakis Damianou
author_sort Anastasia Antoniou
collection DOAJ
description Purpose: This study presents the outcomes of a series of magnetic resonance imaging (MRI)-guided focused ultrasound (MRgFUS) sonications performed on an anatomically accurate head phantom with an embedded tumor simulator to evaluate the effectiveness of partial and complete tumor ablation with obstruction from thin polymer skull mimics. Materials and Methods: The tumor simulator was subjected to single and grid sonications using a single-element concave transducer integrated with an MRI-compatible focused ultrasound (FUS) robotic system. All experiments were carried out in a high-field MRI scanner utilizing proton resonance frequency thermometry and T2-weighted (T2-W) turbo spin echo (TSE) imaging to evaluate the induced thermal effects. FUS transmission through 1-mm thick three-dimensional-printed polymer skull mimics was compared to unobstructed sonication through a circular aperture in the skull model. Results: T2-W TSE imaging demonstrated sharp contrast between the tumor and hyperintense FUS lesions. Complete tumor coverage was achieved through robotic-assisted grid ablation without a skull mimic, as well as with a 1-mm resin skull mimic intervening in the beam. With the lowest attenuation among tested polymers, the resin skull resulted in approximately a 20% reduction in focal temperature change compared to unobstructed sonication, yet still facilitated sharp beam focusing, raising the tumor temperature to ablative levels. Conclusions: The study provides preliminary evidence for the potential application of a thin biocompatible implant to temporarily replace a skull portion facilitating MRgFUS ablation of inoperable tumors using a single-element transducer. The tumor-embedded head phantom was proven effective for testing MRgFUS oncological protocols and equipment.
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publishDate 2025-01-01
publisher Wolters Kluwer Medknow Publications
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spelling doaj-art-e15e62eca65047eaa8b0245d107364da2025-08-20T02:16:03ZengWolters Kluwer Medknow PublicationsJournal of Medical Physics0971-62031998-39132025-01-01501384510.4103/jmp.jmp_177_24Focused Ultrasound Sonications of Tumor Model in Head Phantom under MRI Monitoring: Effect of Skull Obstruction on Focal HeatingAnastasia AntoniouAntreas ChrysanthouLeonidas GeorgiouAntonis ChristofiYiannis RoussakisCleanthis IoannidesKyriakos SpanoudesJufeng ZhaoLiyang YuChristakis DamianouPurpose: This study presents the outcomes of a series of magnetic resonance imaging (MRI)-guided focused ultrasound (MRgFUS) sonications performed on an anatomically accurate head phantom with an embedded tumor simulator to evaluate the effectiveness of partial and complete tumor ablation with obstruction from thin polymer skull mimics. Materials and Methods: The tumor simulator was subjected to single and grid sonications using a single-element concave transducer integrated with an MRI-compatible focused ultrasound (FUS) robotic system. All experiments were carried out in a high-field MRI scanner utilizing proton resonance frequency thermometry and T2-weighted (T2-W) turbo spin echo (TSE) imaging to evaluate the induced thermal effects. FUS transmission through 1-mm thick three-dimensional-printed polymer skull mimics was compared to unobstructed sonication through a circular aperture in the skull model. Results: T2-W TSE imaging demonstrated sharp contrast between the tumor and hyperintense FUS lesions. Complete tumor coverage was achieved through robotic-assisted grid ablation without a skull mimic, as well as with a 1-mm resin skull mimic intervening in the beam. With the lowest attenuation among tested polymers, the resin skull resulted in approximately a 20% reduction in focal temperature change compared to unobstructed sonication, yet still facilitated sharp beam focusing, raising the tumor temperature to ablative levels. Conclusions: The study provides preliminary evidence for the potential application of a thin biocompatible implant to temporarily replace a skull portion facilitating MRgFUS ablation of inoperable tumors using a single-element transducer. The tumor-embedded head phantom was proven effective for testing MRgFUS oncological protocols and equipment.https://journals.lww.com/10.4103/jmp.jmp_177_24focused ultrasoundhead phantommagnetic resonance thermometryrobotic systemt2-weighted turbo spin echo imagingtumor simulator
spellingShingle Anastasia Antoniou
Antreas Chrysanthou
Leonidas Georgiou
Antonis Christofi
Yiannis Roussakis
Cleanthis Ioannides
Kyriakos Spanoudes
Jufeng Zhao
Liyang Yu
Christakis Damianou
Focused Ultrasound Sonications of Tumor Model in Head Phantom under MRI Monitoring: Effect of Skull Obstruction on Focal Heating
Journal of Medical Physics
focused ultrasound
head phantom
magnetic resonance thermometry
robotic system
t2-weighted turbo spin echo imaging
tumor simulator
title Focused Ultrasound Sonications of Tumor Model in Head Phantom under MRI Monitoring: Effect of Skull Obstruction on Focal Heating
title_full Focused Ultrasound Sonications of Tumor Model in Head Phantom under MRI Monitoring: Effect of Skull Obstruction on Focal Heating
title_fullStr Focused Ultrasound Sonications of Tumor Model in Head Phantom under MRI Monitoring: Effect of Skull Obstruction on Focal Heating
title_full_unstemmed Focused Ultrasound Sonications of Tumor Model in Head Phantom under MRI Monitoring: Effect of Skull Obstruction on Focal Heating
title_short Focused Ultrasound Sonications of Tumor Model in Head Phantom under MRI Monitoring: Effect of Skull Obstruction on Focal Heating
title_sort focused ultrasound sonications of tumor model in head phantom under mri monitoring effect of skull obstruction on focal heating
topic focused ultrasound
head phantom
magnetic resonance thermometry
robotic system
t2-weighted turbo spin echo imaging
tumor simulator
url https://journals.lww.com/10.4103/jmp.jmp_177_24
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