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

Diffusion01:12

Diffusion

216.5K
Diffusion is the passive movement of substances down their concentration gradients—requiring no expenditure of cellular energy. Substances, such as molecules or ions, diffuse from an area of high concentration to an area of low concentration in the cytosol or across membranes. Eventually, the concentration will even out, with the substance moving randomly but causing no net change in concentration. Such a state is called dynamic equilibrium, which is essential for maintaining overall...
216.5K
Diffusion01:21

Diffusion

6.3K
Diffusion is a type of passive transport. In passive transport, a substance tends to move from an area of high concentration to an area of low concentration until the concentration is equal across the space. For example, take the diffusion of substances through the air. When someone opens a perfume bottle in a room filled with people, the perfume is at its highest concentration in the bottle and is at its lowest at the edges of the room. The perfume vapor will diffuse, or spread away, from the...
6.3K
Reliability and Validity01:29

Reliability and Validity

13.8K
Reliability and validity are two important considerations that must be made with any type of data collection. Reliability refers to the ability to consistently produce a given result. In the context of psychological research, this would mean that any instruments or tools used to collect data do so in consistent, reproducible ways.
13.8K
Lattice Centering and Coordination Number02:33

Lattice Centering and Coordination Number

11.4K
The structure of a crystalline solid, whether a metal or not, is best described by considering its simplest repeating unit, which is referred to as its unit cell. The unit cell consists of lattice points that represent the locations of atoms or ions. The entire structure then consists of this unit cell repeating in three dimensions. The three different types of unit cells present in the cubic lattice are illustrated in Figure 1.
Types of Unit Cells
Imagine taking a large number of identical...
11.4K
Weighted Mean00:57

Weighted Mean

6.2K
While taking the arithmetic, geometric, or harmonic mean of a sample data set, equal importance is assigned to all the data points. However, all the values may not always be equally important in some data sets. An intrinsic bias might make it more important to give more weightage to specific values over others.
For example, consider the number of goals scored in the matches of a tournament. While computing the average number of goals scored in the tournament, it may be more important to...
6.2K
Center of Gravity00:58

Center of Gravity

6.6K
The center of gravity (COG) of an object is the point where the object's total weight is considered to be concentrated. Knowing the location of the center of gravity is useful when predicting the behavior of a moving object or designing static structures. In a uniform gravitational field, the center of gravity is similar to the center of mass (COM); yet, these two points can be positioned differently. For example, the Moon's center of mass lies very close to its geometric center, but...
6.6K

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

Benchmarking Modern Day Pencil Beam Scanning Proton Therapy Treatment Times: Insights From Real Time Location Service Treatment Time Data.

International journal of particle therapy·2025
Same author

Potential to reduce margins and Shrink targets in patients with intact cervical cancer treated on An MRI guided radiation therapy (MRgRT) system.

Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB)·2024
Same author

Evaluation of a non-metallic dual-port expander for intensity modulated proton therapy.

Journal of applied clinical medical physics·2024
Same author

Design, testing and characterization of a proton central axis alignment device for the dynamic collimation system.

Biomedical physics & engineering express·2023
Same author

Causes of Death Among Patients With Initially Inoperable Pancreas Cancer After Induction Chemotherapy and Ablative 5-fraction Stereotactic Magnetic Resonance Image Guided Adaptive Radiation Therapy.

Advances in radiation oncology·2022
Same author

Prognostic Implications of Early Albuminocytological Dissociation in Guillain-Barré Syndrome.

The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques·2022

相关实验视频

Updated: Jan 22, 2026

Role of Diffusion MRI Tractography in Endoscopic Endonasal Skull Base Surgery
09:53

Role of Diffusion MRI Tractography in Endoscopic Endonasal Skull Base Surgery

Published on: July 5, 2021

4.1K

针对0.35T MR-Linac的多中心扩散权重MRI验证.

Siamak Nejad-Davarani1, Natalia Lutsik1, Kathryn Mittauer2

  • 1Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.

Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB)
|January 20, 2026
PubMed
概括

表面扩散系数 (ADC) 测量在多个低场MR-linacs中是可重复和可重复的,这证实了其适应性放射治疗试验的可靠性. 这支持在多中心研究中使用ADC作为生物标志物.

更多相关视频

Automated Segmentation of Cortical Grey Matter from T1-Weighted MRI Images
06:48

Automated Segmentation of Cortical Grey Matter from T1-Weighted MRI Images

Published on: January 7, 2019

9.4K
Optogenetic Functional MRI
06:06

Optogenetic Functional MRI

Published on: April 19, 2016

15.4K

相关实验视频

Last Updated: Jan 22, 2026

Role of Diffusion MRI Tractography in Endoscopic Endonasal Skull Base Surgery
09:53

Role of Diffusion MRI Tractography in Endoscopic Endonasal Skull Base Surgery

Published on: July 5, 2021

4.1K
Automated Segmentation of Cortical Grey Matter from T1-Weighted MRI Images
06:48

Automated Segmentation of Cortical Grey Matter from T1-Weighted MRI Images

Published on: January 7, 2019

9.4K
Optogenetic Functional MRI
06:06

Optogenetic Functional MRI

Published on: April 19, 2016

15.4K

科学领域:

  • 医学物理 医学物理
  • 放射治疗技术 放射治疗技术
  • 生物标志物开发 生物标志物开发

背景情况:

  • 磁共振线性加速器 (MR-linac) 可用于适应性放射治疗的日常成像.
  • 从扩散权重成像 (DWI) 获得的明显扩散系数 (ADC) 是瘤细胞性和治疗反应的定量生物标志物.
  • 验证ADC的重复性和可重复性对于使用低场MR-linacs的多中心试验至关重要.

研究的目的:

  • 评估ADC测量在低场MR-linacs上的可重复性和可重复性.
  • 为了评估不同的b值集和线圈对ADC可变性的影响.
  • 为了确定门架角度引起的扭曲对ADC准确性的影响.

主要方法:

  • 基于回声平面成像 (EPI) 的DWI在四个机构的幻体上进行.
  • 使用了两个b值集 ([0,30,60,90,120,150,180,200,500,1000]和[0,500,1000]s/mm2) 的结果.
  • 通过在一个部位进行四次扫描来评估可重复性;使用大脑和干线圈在不同部位进行可重复性.

主要成果:

  • 对ADC的变化系数 (COV) 较低,在不同的b值集和线圈中从0.196%到6.902%不等.
  • 多个地点的COV也很低,从0.267%到5.357%不等.
  • 格兰特角扭曲增加了三个b值的正常化根平均平方误差 (nRMSE) 到10.767%和十个b值的6.236%.

结论:

  • 在低场MR-linacs上,ADC测量显示出出色的重复性和可重复性.
  • 这些发现支持使用ADC作为多中心适应性放射治疗试验中可靠的生物标志物.
  • 在线圈和b值集之间的低可变性提高了对ADC临床实用性的信心.