相关实验视频

Updated: Jun 17, 2025

Author Spotlight: A Stable Phantom Material for Optical and Acoustic Imaging

Author Spotlight: A Stable Phantom Material for Optical and Acoustic Imaging

Published on: June 16, 2023

在基于阿加的幻影中估计质子共振频率系数

Antria Filippou¹, Nikolas Evripidou¹, Andreas Georgiou¹

¹Department of Electrical Engineering, Computer Engineering and Informatics, Cyprus University of Technology, Limassol, Cyprus.

Journal of medical physics

|August 12, 2024

概括

针对聚焦超声波研究的阿加尔幻影进行了测试. 新的幻影配方具有特定的和二氧化度,提高了磁共振温度计的准确性,以便在处理过程中更好地监测温度.

科学领域:

生物医学工程生物医学工程
声学声学在声学方面
医疗成像医学成像

背景情况:

基于阿加的幻影被广泛用于高强度聚焦超声波 (HIFU) 研究.
磁共振成像 (MRI) 首选用于HIFU指导和通过质子共振频率 (PRF) 转移MR温度计监测温度.
精确的MR温度计依赖于精确的PRF系数值,这些系数值可以根据幻影组成而有所不同.

研究的目的:

为了估计基于阿加的幻影的PRF系数.
为了研究和二氧化度对PRF系数的影响.
在HIFU研究中确定最佳的幻影组合,用于准确的MR温度计.

主要方法:

准备了7个幻影,其度不同于 (2-6% w/v) 和二氧化 (0-8% w/v).
幻影在30多年的不同声学功率下进行了超声波检测,无论是在实验室还是3T核磁共振扫描仪中.
通过将梯度序列的相位变化与热电偶测量的温度变化相关联,计算出PRF系数.

主要成果:

在相位移和温度变化之间发现了强烈的线性关系 (R2=0.9707-0.9991).
估计的PRF系数在 -0.00336 ± 0.00029 到 -0.00934 ± 0.00050 ppm/°C 之间.
校准的PRF系数产生的温度变化比文献值高1.01-3.01倍,度显示出强烈的负相关性.

结论:

具有6% w/v 和0-8% w/v 的幻影最好模仿组织PRF系数.
这些优化的幻影被推用于HIFU研究.
使用这些估计的PRF系数可以提高MR温度计的准确性并改善HIFU协议评估.

关键词:

在这里,我们可以看到AgarAgarAgar.磁共振成像技术的使用幽灵是什么意思幽灵是什么意思二氧化是二氧化中的一种.测温仪测温仪使用方法超声波超声波是指超声波的使用.

更多相关视频

Agarose-based Tissue Mimicking Optical Phantoms for Diffuse Reflectance Spectroscopy

Agarose-based Tissue Mimicking Optical Phantoms for Diffuse Reflectance Spectroscopy

Published on: August 22, 2018

Controllable Nucleation of Cavitation from Plasmonic Gold Nanoparticles for Enhancing High Intensity Focused Ultrasound Applications

Controllable Nucleation of Cavitation from Plasmonic Gold Nanoparticles for Enhancing High Intensity Focused Ultrasound Applications

Published on: October 5, 2018

相关概念视频

NMR Spectrometers: Resolution and Error Correction

NMR Spectrometers: Resolution and Error Correction

When magnetic nuclei in a sample achieve resonance and undergo relaxation, the signal detected in NMR is an approximately exponential free induction decay. Fourier transform of an exponential decay yields a Lorentzian peak in the frequency domain. Lorentzian peaks in an NMR spectrum are defined by their amplitude, full width at half maximum, and position, where the peak width is governed by the spin-spin relaxation time alone. In real experiments, however, the applied magnetic field is rendered...

Proton (¹H) NMR: Chemical Shift

Proton (¹H) NMR: Chemical Shift

Organic molecules primarily contain carbon and hydrogen atoms. While all the hydrogen isotopes are NMR-active, protium or hydrogen-1 is the most abundant. It has a significant energy separation between its nuclear spin states due to its large gyromagnetic ratio. As per Boltzmann's distribution, an increase in the energy separation implies a greater excess population of nuclei available for excitation, resulting in a strong NMR absorption signal.
Absorption signals of all the protium nuclei...

Double Resonance Techniques: Overview

Double Resonance Techniques: Overview

Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...

¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)

¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)

When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...

¹H NMR of Labile Protons: Temporal Resolution

¹H NMR of Labile Protons: Temporal Resolution

Protons bonded to heteroatoms such as nitrogen and oxygen exhibit a range of chemical shift values. This is due to the varying degree of hydrogen bonding between the proton and the heteroatom in other molecules. The extent of hydrogen bonding affects the electron density around the proton, thereby giving different chemical shift values for the protons in the proton NMR spectrum.
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...

Chemical Shift: Internal References and Solvent Effects

Chemical Shift: Internal References and Solvent Effects

In an NMR sample, precise measurement of the absolute absorption frequencies of nuclei is difficult. A standard internal reference compound is added, and the frequency difference between the reference signal and sample signals is measured.
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...