Pulp ablation therapy by inductive heating: heat generation characteristics in the pulp cavity

Wada, Shigehito; Tazawa, Kenji; Suzuki, Nobuo; Furuta, Isao; Nagano, I.

doi:10.1111/j.1601-0825.2006.01266.x

Cited by 6 publications

(3 citation statements)

References 21 publications

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“…all measurements were obtained at 4 hz, 30 V pp magnetic solenoid excitation voltage. a limitation of this method is the possible generation of heat by the particles as they are exposed to a magnetic field [21]. heat generation may damage the surrounding tissue in in vivo measurements; thus, further investigation into heat generation for varying exposure times is necessary before in vivo use.…”

Section: Discussionmentioning

confidence: 99%

Frequency- and phase-sensitive magnetomotive ultrasound imaging of superparamagnetic iron oxide nanoparticles

Evertsson

Cinthio

Fredriksson

et al. 2013

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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It has recently been demonstrated that superparamagnetic iron oxide nanoparticles can be used as magnetomotive ultrasound contrast agents. A time-varying external magnetic field acts to move the particles and, thus, the nanoparticle-laden tissue. However, the difficulty of distinguishing this magnetomotive motion from undesired movement induced in regions without nanoparticles or other motion artifacts has not been well reported. Using a high-frequency linear-array system, we found that displacements outside nanoparticle-laden regions can be similar in magnitude to those in regions containing nanoparticles. We also found that the displacement outside the nanoparticle regions had a phase shift of approximately π radians relative to that in the nanoparticle regions. To suppress signals arising from undesirable movements, we developed an algorithm based on quadrature detection and phase gating at the precise frequency of nanoparticle displacement. Thus, clutter at other frequencies can be filtered out, and the processed signal can be color-coded and superimposed on the B-mode image. The median signal-to-clutter ratio improvement using the proposed algorithm was 36 dB compared with simply summing the movement energy at all frequencies. This clutter rejection is a crucial step to move magnetomotive ultrasound imaging of nanoparticles toward in vivo investigations.

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Section: Discussionmentioning

confidence: 99%

Frequency- and phase-sensitive magnetomotive ultrasound imaging of superparamagnetic iron oxide nanoparticles

Evertsson

Cinthio

Fredriksson

et al. 2013

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…13 Therefore, when cells or tissue labeled with superparamagnetic nanoparticles are exposed to a magnetic field, they tend to move toward lower magnetic potential. 15 In most cases, the labeled cells or tissue are located within a viscoelastic tissue background. Therefore, internal tissue elasticity forces act against the magnetically induced displacement.…”

Section: Introductionmentioning

confidence: 99%

In vivo pulsed magneto-motive ultrasound imaging using high-performance magnetoactive contrast nanoagents

Mehrmohammadi

Shin

et al. 2013

Nanoscale

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Previously, pulsed magneto-motive ultrasound (pMMUS) imaging has been introduced as a contrast-agent-assisted ultrasound-based imaging modality capable of visualizing biological events at the cellular and molecular level. In pMMUS imaging, a high intensity pulsed magnetic field is used to excite cells or tissue labeled with magnetic nanoparticles. Then, ultrasound (US) imaging is used to monitor the mechanical response of the tissue to an externally applied magnetic field (i.e., tissue displacement). Signal to noise ratio (SNR) in pMMUS imaging can be improved by using superparamagnetic nanoparticles with larger saturation magnetization. Metal-doped magnetic nanoparticles with enhanced tunable nanomagnetism are suitable candidates to improve the SNR and, therefore, sensitivity of pMMUS imaging, which is essential for in vivo pMMUS imaging. In this study, we demonstrate the capability of pMMUS imaging to identify the presence and distribution of zinc-doped iron oxide nanoparticles in live nude mice bearing A431 (human epithelial carcinoma) xenograft tumors.

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“…Consequently, using MMUS to image deeper tissue structures is limited by thermal constraints. 14 Furthermore, several hardware limitations are associated with the relatively long operation time in harmonic MMUS that generates an enormous amount of heat within both the current amplifier and the magnetic coil. Moreover, the strong harmonic magnetic field requires a high current to drive the coil, which is not feasible at higher frequencies owing to coil inductance.…”

mentioning

confidence: 99%

Pulsed Magneto-motive Ultrasound Imaging Using Ultrasmall Magnetic Nanoprobes

Mehrmohammadi

Mallidi

et al. 2011

Mol Imaging

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Nano-sized particles are widely regarded as a tool to study biologic events at the cellular and molecular levels. However, only some imaging modalities can visualize interaction between nanoparticles and living cells. We present a new technique, pulsed magneto-motive ultrasound imaging, which is capable of in vivo imaging of magnetic nanoparticles in real time and at sufficient depth. In pulsed magneto-motive ultrasound imaging, an external high-strength pulsed magnetic field is applied to induce the motion within the magnetically labeled tissue and ultrasound is used to detect the induced internal tissue motion. Our experiments demonstrated a sufficient contrast between normal and iron-laden cells labeled with ultrasmall magnetic nanoparticles. Therefore, pulsed magneto-motive ultrasound imaging could become an imaging tool capable of detecting magnetic nanoparticles and characterizing the cellular and molecular composition of deep-lying structures.

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Pulp ablation therapy by inductive heating: heat generation characteristics in the pulp cavity

Cited by 6 publications

References 21 publications

Frequency- and phase-sensitive magnetomotive ultrasound imaging of superparamagnetic iron oxide nanoparticles

Frequency- and phase-sensitive magnetomotive ultrasound imaging of superparamagnetic iron oxide nanoparticles

In vivo pulsed magneto-motive ultrasound imaging using high-performance magnetoactive contrast nanoagents

Pulsed Magneto-motive Ultrasound Imaging Using Ultrasmall Magnetic Nanoprobes

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