Jove
Visualize
联系我们
JoVE
x logofacebook logolinkedin logoyoutube logo
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关概念视频

High-Resolution Mass Spectrometry (HRMS)01:15

High-Resolution Mass Spectrometry (HRMS)

1.4K
The resolution of a mass spectrometer depends on the efficiency of separating ions with different ion masses. The mass of an atom is approximated to the sum of the masses of protons and neutrons inside, considering the masses of protons and neutrons as equal. However, the masses of the proton (1.6726 × 10−24 g) and neutron (1.6749 × 10−24 g) are not truly equal. There is a minor error in the expression of atomic masses relative to the simplest atom of hydrogen. For...
1.4K
Thomson's e/m Experiment01:19

Thomson's e/m Experiment

3.7K
In a beam of charged particles created by a heated cathode, the particles move at different speeds. However, many applications need a beam with uniform particle speeds. An arrangement known as a velocity selector uses electric and magnetic fields to pick particles with a particular speed from the beam.
A particle with charge q, speed v, and mass m enters an area from the top, where the magnetic and electric fields are perpendicular both to the particle's motion and to one another. The...
3.7K
NMR Spectrometers: Resolution and Error Correction01:14

NMR Spectrometers: Resolution and Error Correction

698
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...
698
Chemical Shift: Internal References and Solvent Effects01:17

Chemical Shift: Internal References and Solvent Effects

643
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...
643

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
Same author

MRI-Only Simulation for Prostate MRI-Guided SBRT.

Practical radiation oncology·2026
Same author

From Cellular Radiosensitivity to Precision Radiotherapy: Integrating Functional Assays, Genomics, and Clinical Modeling.

Cancers·2026
Same author

PRISM: An open-source framework for regularized material decomposition on a novel kV dual-layer imager.

Medical physics·2026
Same author

Interobserver image registration variability impacts on stereotactic arrhythmia radioablation (STAR) target margins.

Biomedical physics & engineering express·2026
Same author

Patient outcome prognosis for external beam radiation therapy using CBCT-based radiomics: a systematic review.

Biomedical physics & engineering express·2025
Same author

CT online adaptive radiotherapy is associated with dosimetric and acute toxicity improvements in prostate cancer treatment.

Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology·2025

相关实验视频

Updated: Jul 4, 2025

Characterization of Recombination Effects in a Liquid Ionization Chamber Used for the Dosimetry of a Radiosurgical Accelerator
07:31

Characterization of Recombination Effects in a Liquid Ionization Chamber Used for the Dosimetry of a Radiosurgical Accelerator

Published on: May 9, 2014

11.8K

基于MV的相对电子密度估计 (iMREDe) 用于MR-LINAC剂量计算.

Marios Myronakis1, Yue-Houng Hu1, Matthew William Jacobson1

  • 1Department of Radiation Oncology, Brigham and Women's Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts, USA.

Medical physics
|February 3, 2024
PubMed
概括

这项研究开发了一种新方法,使用平面成像仪和初级MV光束来为MR-LINAC系统创建精确的电子密度图. 这一进步有助于适应性放射治疗的规划,提高效率并减少不确定性.

关键词:
在CBCT中,CBCT是CBCT.在EPID中,我们可以使用EPID.在 MR-LINACAC 中.在MV成像中使用MV成像.电子密度 的电子密度.

更多相关视频

Dosimetry for Cell Irradiation using Orthovoltage 40-300 kV X-Ray Facilities
06:51

Dosimetry for Cell Irradiation using Orthovoltage 40-300 kV X-Ray Facilities

Published on: February 20, 2021

5.0K
Expedited Radiation Biodosimetry by Automated Dicentric Chromosome Identification ADCI and Dose Estimation
10:33

Expedited Radiation Biodosimetry by Automated Dicentric Chromosome Identification ADCI and Dose Estimation

Published on: September 4, 2017

15.7K

相关实验视频

Last Updated: Jul 4, 2025

Characterization of Recombination Effects in a Liquid Ionization Chamber Used for the Dosimetry of a Radiosurgical Accelerator
07:31

Characterization of Recombination Effects in a Liquid Ionization Chamber Used for the Dosimetry of a Radiosurgical Accelerator

Published on: May 9, 2014

11.8K
Dosimetry for Cell Irradiation using Orthovoltage 40-300 kV X-Ray Facilities
06:51

Dosimetry for Cell Irradiation using Orthovoltage 40-300 kV X-Ray Facilities

Published on: February 20, 2021

5.0K
Expedited Radiation Biodosimetry by Automated Dicentric Chromosome Identification ADCI and Dose Estimation
10:33

Expedited Radiation Biodosimetry by Automated Dicentric Chromosome Identification ADCI and Dose Estimation

Published on: September 4, 2017

15.7K

科学领域:

  • 医学物理 医学物理
  • 放射治疗技术 放射治疗技术
  • 图像重建 图像的重建

背景情况:

  • 磁共振线性加速器 (MR-LINAC) 系统对于实时适应性放射治疗至关重要.
  • 对空气腔的MRI成像和电子密度估计的挑战阻碍了治疗规划的效率和准确性.
  • 由于电子密度图不准确,目前的方法可能会引入剂量计算的不确定性.

研究的目的:

  • 用平板成像仪使用初级MV光束演示生成准确的电子密度图.
  • 在MR-LINAC系统中验证一种用于生成电子密度图的新技术.
  • 提高适应性放射治疗规划的效率和准确性.

主要方法:

  • 蒙特卡罗模拟ViewRay MRIdian MR-LINAC系统,包括在平板探测器上的磁场效应.
  • 对数字幻影和头癌患者进行360度的模拟投影采集.
  • 开发并应用了人工物校正技术 (空气规范化,内涂),并生成电子密度图以与基于CT的图进行比较.

主要成果:

  • 磁场在50mT以上的磁场强度下显著影响探测器的点分布功能.
  • 闪光校正有效地删除了重建文物,而不会影响噪声线性.
  • 拟议的方法在电子密度图中与治疗规划CT相比,平均相对差异为11%.

结论:

  • iMREDe技术成功地为ViewRay MR-LINAC使用平面成像仪和MV光束生成了准确的电子密度.
  • 这种方法显示了改进MR-LINAC系统中的适应性放射治疗工作流程的可行性.
  • 这些发现代表了减少适应性放射治疗规划时间和努力的重要一步.