相关实验视频
Updated: Feb 6, 2026

14:25
Determining 3D Flow Fields via Multi-camera Light Field Imaging
Published on: March 6, 2013
17.2K
笔束扫描质子格子放射疗法:单场与多场优化优化:单场与多场优化
Shouyi Wei1, Lee Xu1, Hang Qi1
1New York Proton Center, New York, NY, United States.
Frontiers in oncology
|February 5, 2026
概括
在质子网辐射疗法 (LRT) 中,单场优化 (SFO) 和多场优化 (MFO) 都起到了很好的作用. MFO减少了皮肤剂量,但SFO提供了更好的计划强度来应对不确定性.
科学领域:
- 辐射瘤学 辐射瘤学
- 医学物理 医学物理
背景情况:
- 笔光束扫描 (PBS) 质子晶格放射疗法 (LRT) 是治疗大型瘤的先进技术.
- 优化剂量分配对于最大限度地提高LRT的治疗比率至关重要.
研究的目的:
- 为了比较PBS质子LRT的单场优化 (SFO) 与多场优化 (MFO) 的临床优缺点.
- 评估两个优化技术的计划质量和稳定性.
主要方法:
- 使用RayStation (v2023B) 对12名患有体积庞大的头,胸部或腹部瘤的患者进行回顾性计划.
- 剂量处方:18 Gy到6-8个顶点中的每一个和3 Gy到瘤总体积 (GTV).
- 在不同的场景下评估剂量参数 (GTV D平均值,D95%,gEUD;顶点D90%;PVDR;皮肤D1%) 和计划稳定性.
主要成果:
- 无论是SFO还是MFO,都实现了接近4.0的峰值-谷值剂量比率 (PVDR).
- 与单场优化 (SFO) 相比,多场优化 (MFO) 显著减少了25%的皮肤剂量 (D1%).
- 与SFO计划相比,MFO计划在稳健分析下显示了PVDR,GTV Dmean和皮肤D1%的偏差较大.
结论:
- 通过当前的质子疗法技术和计划系统,SFO和MFO都在临床上可实现.
- 在治疗不确定性下,SFO表现出卓越的计划稳定性,保持优化指标.
- 在节省关键器官方面,MFO具有优势,特别是减少皮肤剂量.
相关概念视频
Field Effect Transistor
1.2K
Field-effect transistors (FETs) are integral to electronic circuits and distinguished by their three-terminal setup: the gate, drain, and source. These transistors operate as unipolar devices, which utilize either electrons or holes as charge carriers, in contrast to bipolar transistors, which use both types of carriers. The primary function of the FET is to modulate the flow of these carriers from the source to the drain through a channel. The voltage difference between the gate and source...
1.2K
Electric Field
12.9K
Consider two point charges, each exerting Coulomb force on the other. It is possible to describe the Coulomb interaction via an intermediate step by defining a new physical quantity called the electric field.
In the new picture, imagine that the first charge sets up an electric field independent of all other charges in the universe. When another charge comes in its vicinity, the second charge experiences an electric force depending on the electric field at that point. The source charge does not...
In the new picture, imagine that the first charge sets up an electric field independent of all other charges in the universe. When another charge comes in its vicinity, the second charge experiences an electric force depending on the electric field at that point. The source charge does not...
12.9K
Magnetic Fields
7.4K
A moving charge or a current creates a magnetic field in the surrounding space, in addition to its electric field. The magnetic field exerts a force on any other moving charge or current that is present in the field. Like an electric field, the magnetic field is also a vector field. At any position, the direction of the magnetic field is defined as the direction in which the north pole of a compass needle points.
A magnetic field is defined by the force that a charged particle experiences...
A magnetic field is defined by the force that a charged particle experiences...
7.4K
Electromagnetic Fields
2.8K
Electric fields generated by static charges, often referred to as electrostatic fields, are characteristically different from electric fields created by time-varying magnetic fields. While the former is a conservative field, implying that no net work is done on a test charge if it goes around in a complete loop in the field, the latter is, by definition, not a conservative field; net work is done, and it is proportional to the rate of change of magnetic flux.
However, the observation of...
However, the observation of...
2.8K
Lattice Centering and Coordination Number
11.7K
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...
Types of Unit Cells
Imagine taking a large number of identical...
11.7K
Electric Field Inside a Conductor
7.5K
When a conductor is placed in an external electric field, the free charges in the conductor redistribute and very quickly reach electrostatic equilibrium. The resulting charge distribution and its electric field have many interesting properties, which can be investigated with the help of Gauss's law.
Suppose a piece of metal is placed near a positive charge. The free electrons in the metal are attracted to the external positive charge and migrate freely toward that region. This region then...
Suppose a piece of metal is placed near a positive charge. The free electrons in the metal are attracted to the external positive charge and migrate freely toward that region. This region then...
7.5K
![Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59399.jpg&w=3840&q=50)
