Shaping and Focusing Magnetic Field in the Human Body: State-of-the Art and Promising Technologies

Rotundo, Sabrina; Brizi, Danilo; Flori, Alessandra; Giovannetti, Giulio; Menichetti, Luca; Monorchio, Agostino

doi:10.3390/s22145132

Cited by 23 publications

(21 citation statements)

References 96 publications

(149 reference statements)

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“…Also, although craniectomy certainly induced a CSF leakage, CSF may not significantly impact the magnetic decay, which depends mainly on the distance from the source and not on the quality of the intermediate tissues. 31 Even we could not record the secondary electric currents induced by TMS pulses, the composition of the living tissues and their electrical properties is different, and the electrode induction differs from the postmortem model.…”

Section: Limitationsmentioning

confidence: 99%

Field recordings of transcranial magnetic stimulation in human brain postmortem models

Quesada,

Fauchon,

Pommier

et al. 2024

PR9

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Introduction: The ability of repetitive transcranial magnetic stimulation (rTMS) to deliver a magnetic field (MF) in deep brain targets is debated and poorly documented. Objective: To quantify the decay of MF in the human brain. Methods: Magnetic field was generated by single pulses of TMS delivered at maximum intensity using a flat or angulated coil. Magnetic field was recorded by a 3D-magnetic probe. Decay was measured in the air using both coils and in the head of 10 postmortem human heads with the flat coil being positioned tangential to the scalp. Magnetic field decay was interpreted as a function of distance to the coil for 6 potential brain targets of noninvasive brain stimulation: the primary motor cortex (M1, mean depth: 28.5 mm), dorsolateral prefrontal cortex (DLPFC: 28 mm), secondary somatosensory cortex (S2: 35.5 mm), posterior and anterior insulae (PI: 38.5 mm; AI: 43.5 mm), and midcingulate cortex (MCC: 57.5 mm). Results: In air, the maximal MF intensities at coil center were 0.88 and 0.77 T for the flat and angulated coils, respectively. The maximal intracranial MF intensity in the cadaver model was 0.34 T, with a ∼50% decay at 15 mm and a ∼75% MF decay at 30 mm. The decay of the MF in air was similar for the flat coil and significantly less attenuated with the angulated coil (a ∼50% decay at 20 mm and a ∼75% MF decay at 45 mm). Conclusions: Transcranial magnetic stimulation coil MFs decay in brain structures similarly as in air, attenuation with distance being significantly lower with angulated coils. Reaching brain targets deeper than 20 mm such as the insula or Antérior Cingulate Cortex seems feasible only when using angulated coils. The abacus of MF attenuation provided here can be used to adjust modalities of deep brain stimulation with rTMS in future research protocols.

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Section: Limitationsmentioning

confidence: 99%

Field recordings of transcranial magnetic stimulation in human brain postmortem models

Quesada,

Fauchon,

Pommier

et al. 2024

PR9

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“…Magnetism is considered one of the best non-invasive external stimuli due to the facile tissue penetration [220] and the real-time response [106]. The application of an external magnetic field is widely used for medical imaging (magnetic resonance imaging, MRI).…”

Section: Response To External Stimulimentioning

confidence: 99%

Responsive Supramolecular Polymers for Diagnosis and Treatment

Martínez-Orts,

Pujals

2024

IJMS

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Stimuli-responsive supramolecular polymers are ordered nanosized materials that are held together by non-covalent interactions (hydrogen-bonding, metal-ligand coordination, π-stacking and, host–guest interactions) and can reversibly undergo self-assembly. Their non-covalent nature endows supramolecular polymers with the ability to respond to external stimuli (temperature, light, ultrasound, electric/magnetic field) or environmental changes (temperature, pH, redox potential, enzyme activity), making them attractive candidates for a variety of biomedical applications. To date, supramolecular research has largely evolved in the development of smart water-soluble self-assemblies with the aim of mimicking the biological function of natural supramolecular systems. Indeed, there is a wide variety of synthetic biomaterials formulated with responsiveness to control and trigger, or not to trigger, aqueous self-assembly. The design of responsive supramolecular polymers ranges from the use of hydrophobic cores (i.e., benzene-1,3,5-tricarboxamide) to the introduction of macrocyclic hosts (i.e., cyclodextrins). In this review, we summarize the most relevant advances achieved in the design of stimuli-responsive supramolecular systems used to control transport and release of both diagnosis agents and therapeutic drugs in order to prevent, diagnose, and treat human diseases.

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“…Therefore, it is suitable for applications that require surface heating and could have some degree of penetration depending on the intensity of the magnetic field. Other geometries, such as a helical configuration, require the target object to be inserted inside the coil [48][49][50]. A 'pancake' planar configuration met this project's goal of applying AMFs to other surfaces.…”

Section: Magnetic Field Generator Designmentioning

confidence: 99%

Development of handheld induction heaters for magnetic fluid hyperthermia applications and in-vitro evaluation on ovarian and prostate cancer cell lines

Castro-Torres

Mendéz²,

Torres‐Lugo³

et al. 2023

Biomed. Phys. Eng. Express

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Abstract— Objective: Magnetic fluid hyperthermia (MFH) is a still experimental technique found to have a potential application in the treatment of cancer. The method aims to reach around 41–47°C in the tumor site by exciting magnetic nanoparticles with an externally applied alternating magnetic field (AMF), where cell death is expected to occur. Applying AMFs with high spatial resolution is still a challenge. The AMFs from current and prospective MFH applicators cover relatively large areas; being not suitable for patients having metallic implants near the treatment area. Thus, there will be a clinical need for smaller magnetic field applicators. To this end, a laparoscopic induction heater (LIH) and a transrectal induction heater (TRIH) were developed. Methods: Miniature “pancake” coils were wound and inserted into 3D printed enclosures. Ovarian (SKOV-3, A2780) and prostate (PC-3, LNCaP) cancer cell lines were used to evaluate the instruments’ capabilities in killing cancer cells in vitro, using Synomag®-D nanoparticles as the heat mediators. NIH3T3 normal cell lines were also used with both devices to observe if these cells tolerated the conditions applied. Results: Magnetic field intensities reached by the LIH and TRIH were 42.6 kA/m at 326 kHz and 26.3 kA/m at 303 kHz, respectively. Temperatures reached in the samples were 41°C by the LIH and 43°C by the TRIH. Both instruments successfully accomplished killing cancer cells, with minimal effects on normal cells. Conclusion: This work presents the first line of handheld medical induction heaters and have the potential to be a complement to existing cancer therapies. Significance: These instruments could enable the development of MFH modalities that will facilitate the clinical translation of this thermal treatment.

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Shaping and Focusing Magnetic Field in the Human Body: State-of-the Art and Promising Technologies

Cited by 23 publications

References 96 publications

Field recordings of transcranial magnetic stimulation in human brain postmortem models

Field recordings of transcranial magnetic stimulation in human brain postmortem models

Responsive Supramolecular Polymers for Diagnosis and Treatment

Development of handheld induction heaters for magnetic fluid hyperthermia applications and in-vitro evaluation on ovarian and prostate cancer cell lines

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