chapter 14 -- medical applications of nuclear technology
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Chapter 14 -- Medical Applications of Nuclear Technology. Xiaodong He Radiotherapy Center Shanghai Pulmonary Hospit al. - PowerPoint PPT PresentationTRANSCRIPT
Chapter 14 -- Medical Applications of Nuclear Technology
Xiaodong He
Radiotherapy Center
Shanghai Pulmonary Hospital
Just after the moment of discovery of X rays, the importance of X rays in medical diagnosis was immediately apparent , and within months of its discovery, the bactericidal action of X rays and their ability to destroy tumors were revealed.
prologueprologue
Today, both diagnostic and therapeutic medicine as well as medical research depend critically on many increasingly sophisticated applications of nuclear radiation and radioisotopes.
Nuclear medicine
核医学
Medical Applications of Nuclear Technology
Radiation Oncology
放射肿瘤治疗学
RadiationImage
+NMR
Medical Applications of Nuclear Technology are constituted by three parts above.
Nuclear medicineNuclear medicine
Positron Emission Tomography
Single Photon Emission Computerized Tomography SPECT
γ Camera , Bone Scanning
Radioimmunoassay , RIA in vitro
体
内Radionuclide Therapy Tumor, hyperthyroidism 甲亢 , etc.
PET/CT
Radionuclide analysis in vitro + in vivo
According to the radioactive isotope analysis results of the Oak Ridge( 橡树岭 ) lab:
In one year, 98% of the atoms of organism (human body) is replaced.
The body does not have a constant material.
And, in certain time the materials inside body are to produce thousands of times biological chemical reactions every second.
Radionuclide analysis for human species
Radioimmunoassay ( more compactly as RIA 放射免疫技术)
RIA as a kind of technology take the both advantages of accuracy and sensitivity of the radioactive isotope measurement and the specificity of the reaction of antigen and antibody.
It is a new in vitro technology for ultra trace (10-
9~10-15g) material detection. 放射免疫技术为一种将放射性同位素测量的高度灵敏性、精确性和抗原抗体反应的特异性相结合的体外测定超微量(10-9~10-15g) 物质的新技术。
Broadly, all the assay technologies via immune reactions by antigen and antibody which tagged by radioactive isotopes can be called RIA
广义来说,凡是应用放射性同位素标记的抗原或抗体,通过免疫反应测定的技术,都可称为放射免疫技术 。
So far has development to the fifth generation of RIA technology. It is characterised by the combination of magnetic particles and RIA or IRMA (immunoradiometric assay) .
PET / CT Positron emission tomography + CT
PET/CT is a perfect fusing of PET and CT. It can Provide detailed lesion function and
metabolic information of moleculars by PET , and in the same time, provide the accurate lesion anatomic localization by CT.
It is characterised by sensitivity, accuration, specific and accurate location.
It is extensive used in radiotherapy, and also be called the “high-tech coronal of Modern medicine”.
The Mechanics of PET
The clinical imaging process of PET is as followes:
a. Mark the radioactive isotopes which can emit positrons (such as F-18) to compounds which be gonna to participate in tissue blood flow, or in metabolic process.
b. Inject the tagged compounds into human body.
c. The emission positron from radio-isotope can shift 1 mm in human body, and then combined with an electron in tissues and annihilate to produce two equal energy (511 KeV) and opposite γ photons.
It was recognized that detection of these photons, using the property that they are emitted simultaneously in opposite directions, would permit description, in three dimensions, of the distribution of the radionuclides in the body.
Sketch map of PET
PET imaging of an object surrounded by a ring of detectors. Annihilation photons γa are recorded by detectors on opposite sides of the ring,
the relative intensities allow determination of the mass thickness of the distances L1 and L2 in the patient through which these photons travel.
d. Annihilation photons leaving the body are detected by an array of detectors that surround the patient.
Events are recorded only when two detectors each detect an annihilation photon simultaneously, i.e., within 10 to 25 ns of each other. Events separated further in time are not recorded.
The line joining the two recording detectors is a line of response (LOR) along which the annihilation photons have traveled and on which the positron decay occurred.
This coincident detection technique allows a determination of the direction of the annihilation photons without the physical collimation needed in SPECT. For this reason coincident detection is often called electronic collimation.
BGO : 锗酸铋 (Bismuth Germanium Oxide)PMT:光电倍增管 (Photo Multiplier Tube)
Radiation Imaging & NMRRadiation Imaging & NMR
4D fast CT and 4D fast NMR
Function NMR , NMR spectrum analysation
Magnetic Resonance Imaging ( NMR )
Computed Tomography ( CT )计算机断层成像
X ray Radiography, and DSA ( Digital subtraction angiography 数字减影血管造影术)
Background & Rationale
Convolution
线性系统 h(t),输入 e(t),输出y(t)
卷积的来源: 物理中类似对于冲量不变的研究。在用 t 做横坐标
、 F 做纵坐标的坐标系中,就如同一个面积不变的长方形,底边被挤的越窄,高度被挤的越高。在数学中它可以被挤到无限高,但即使它无限瘦、无限高、但它仍然保持面积不变。
可以对它进行积分,求面积。于是“卷积” 这个数学怪物就这样诞生了。
卷积可以描述为一个过程
卷积可以描述为一个过程
这两个可认为是经典的衍射问题,信号处理也会遇到类似的问题。
在晶体 X 射线衍射中,实验测量出的衍射峰的线形 h ,包括两部分:晶体的贡献 f 和衍射仪器的贡献 g , h 、 f 和 g 三者的关系满足卷积运算:
讲卷积离不开傅立叶变换。 在晶体衍射里,傅立叶变换关联着两个完全不同的空间:现实的笛卡儿空间和倒易的衍射空间。
Fourier transformation
傅里叶变换能将满足一定条件的某个函数表示成三角函数(正弦和 / 或余弦函数)或者它们的积分的线性组合。
Two features :1. 傅立叶变换是线性算子 , 若赋予适当的范数 , 它还是酉算子;
2. 正弦基函数是微分运算的本征函数 , 从而使得线性微分方程的求解可以转化为常系数的代数方程的求解 . 在线性时变复杂的卷积运算为简单的乘积运算 , 从而提供了计算卷积的一种简单手段。
i( ) ( ) dtF f t e t
Laplace transformation
拉氏变换的物理意义:建立了时域和复频域之间的联系。
其数学意义:将微分方程转化为代数方程,简化了计算。
傅氏与拉氏变换的区别在于,拉氏变换是处理微分方程的,它的最初目的是将微分运算转化为容易求解的代数运算。而 fourier 变换是将连续的时间域信号转变到频率域;它可以说是 laplace 变换的特例;
拉氏存在条件比 fourier 变换要宽,是将连续的时间域信号变换到复频率域(整个复平面,而 fourier变换此时可看成仅在 jΩ 轴);
Z 变换则是连续信号经过理想采样之后的离散信号的 laplace 变换,再令 z=esT 时的变换结果( T为采样周期),所对应的域为数字复频率域,此时数字频率 ω=ΩT 。
它与拉氏变换一样,都是将时域映射到频域。 拉普拉斯变换与 Z 变换的联系;其本质区别在于
拉氏变换处理的是时间上连续的问题, Z 变换处理的是时间上分立的问题。
Question 1 What is the main difference between fourier
transformation and laplace transformation ? main difference : laplace transformation is in whole complex
plane , and fourier transformation is just in imaginary axis.
Question 2 What is the physical and mathematical
significance of laplace transformation?
physical significance: It establishes the relationship between the time domain and complex frequency domain.
mathematical significance: Converts differential equation to Algebraic equation, so as to simplify the calculation.
NMR
原子核在外磁场作用下发生能级分裂 , 在一定射频场作用下吸收其能量发生能级跃迁的现象。
塞曼能级分裂
射频脉冲 E = hνradio frequency pulse, RF
核磁共振
The quantum mechanical describes for NMR
小结
Background & Rational
Quantum mechanics
Fourier transformation
Radiation OncologyRadiation Oncology
Brachytherapy
Teletherapy
TeletherapyTeletherapy
P, C P, C
X raysX rays
ElectronsElectrons
Elements used in teleradiotherapy
TeletherapyTeletherapy
4DRT4DRT
CRTCRT
IMRTIMRT
Techniques used in teleradiotherapy
BrachytherapyBrachytherapy
IodineIodine
Ir-192Ir-192Cobalt-60Cobalt-60
BNCTBNCT boron neutronboron neutron
capture therapycapture therapy
Elements used in brachytherapy
BrachytherapyBrachytherapy近距离放疗近距离放疗After loading After loading radiotherapyradiotherapy
后装放疗后装放疗
Intracavity Intracavity afterloading afterloading radiotherapyradiotherapy腔内后装放疗腔内后装放疗
(125)I implantation Brachytherapy碘近距离粒子种植放疗
Seeds implantSeeds implant
Interstitial implant Interstitial implant brachytherapybrachytherapy 组织间插植组织间插植
Techniques applied in brachyradiotherapy
After-loading Intracavitary unit
后装治疗机
A 点:宫颈口旁 2cm
上 2cm
B 点: A 点外 3cm
Paris Dosimetry System巴黎剂量学系统
植入辐射源呈直线型、彼此相互平行、各线源等分中心位于同一平面、各源相互等间距、排布呈正方形或等边三角形、源的线性活度均匀且等值、线源与过中心点的平面垂直。
Interstitial Radiation组织间插植治疗
Synopsis of the Synopsis of the Tele-radiotherapyTele-radiotherapy
外外放射治疗简介放射治疗简介
What is Radiotherapy (RT)What is Radiotherapy (RT)
RT is a clinical subject of treating cancers by applying the theories and means of high energy rays to irradiate tumor targets.
研究、应用高能放射线治疗肿瘤的原理和方法的临床治疗学科
What is RadiWhat is Radiation ation ??
The most frequently used elements in RT
Candidate particles
靶分子
电离
SSB 单链断裂
诱发自由基击出电子
DSB 双链断裂
氧固定
电子转移
potential lethal damage潜在致死性损伤
乏氧 时相( 稳态 )
双链修复
lethal damage
致死性损伤
sublethal damage亚致死性损伤
单链复制
错误复制
致畸致癌
时相 组织
间期死亡
增殖期死
亡 急性反应
慢性反应
ionization
Why RT can cure cancer disease ? -- 辐射损伤与修复
1. RT is based on ionizing radiation 2. Ionization can induce trauma ( injury )
tumor
Normal tissue
3. Some type of cancer more sensitive to ionization irradiation than normal cells (sigmoid curves)
More separating the curves in dose is,
more higher the curable probability be.
The role of RT in The role of RT in tumor treatmenttumor treatment
Till now, surgery, RT and chemotherapy are the Till now, surgery, RT and chemotherapy are the major three ways to treat cancers. Nearly 2/3 of cancer major three ways to treat cancers. Nearly 2/3 of cancer patients need RT. patients need RT.
But radiotherapy has no good response for some patients, the main reason is that the 10%- 50 % of hypoxic cells in solid tumors have low response to radiotherapy
Out of control
How the RT is performed?How the RT is performed? The flow chart of RT The flow chart of RT 放疗流程图放疗流程图
Medical evaluation评估 (include pathology , physical ,lab test, image)
Medical evaluation评估 (include pathology , physical ,lab test, image)
QAQA Portal
verification射野验证
Portal verification射野验证
treatment treatment follow up随访
follow up随访
TPS 计划设计TPS 计划设计CT SCAN
PET/CT MRITo localization
CT SCANPET/CT MRITo localization
Virtual simulation and image fusion
虚拟模拟和图像融合
Virtual simulation and image fusion
虚拟模拟和图像融合
Simplified Radiotherapy Treatment FlowSimplified Radiotherapy Treatment Flow
The composition of RT The composition of RT 放疗学构成放疗学构成
Radiotherapy includes four branches:
1. Radiation Oncology (放射肿瘤学)
2. Radiation Physics (放射物理学)
3. Radiobiology (放射生物学)
4. Radiation Technology (放射技术学)
A. Some important concepts
1. Liner Energy Transfer. (线性能量传输)
LET for short
LET =△E
△X
KeV/μ m
2. Ionization induced Direct and Indirect effects
电离对靶分子的间接作用与直接作用
Direct : Directly act on target molecules
( Break DNA double strands ) 直接作用 : 直接引起 DNA双链断裂
Indirect : Affect target molecules via ionized
& excitated water molecules H2O 间接作用:通过水分子电离、激发 再作用到靶分子
3. Oxygen Enhancement Ratio . OER
(氧增强比)
OER =
D0 (dose for killing hypoxic cells 乏氧细胞 )
D0 (dose for killing aerobic cells 有氧细胞 )
4. Relative Biological Effect . RBE
(相对生物效应)
RBE =
Doses which create a certain bio-effect by one standard ray 产生一定生物效应标准射线剂量
Doses which create the same bio-effect by another ray 产生同样生物效应另一种射线剂量
5. The characteristic of high LET rays
高 LET 射线的特点a. There is a Bragg Peak
b. RBE 大, OER 小c. Direct effects is major 直接作用为主,致死性损伤
d. Cell phase independent
细胞时相差异小 (Only for high LET)
6 、 Absorbed Dose 吸收剂量
D = ∆Eab / ∆m ∆Eab is absorbed energy ;∆ m is mass ;
物理量 定义 SI单位 旧单位 换算 Exposure (X)
Dose (D)
Equivalent Dose (H)
Activity (A)
7 、 Kerma (比释动能) Kinetic energy released per unit mass
K = dEtr / dmIt applies to indirect ionizing radiation
It is differ from the Karma 业障 in Buddhism.它是一个适用于间接电离辐射,如光子和中子的非随机量。它计算从间接电离辐射转移到直接电离辐射的平均数量值,不考虑转移后的发生的情况。下列讨论将局限于光子。光子的能量分两步授予给物质。第一步,光子辐射通过多种光子相互作用(光电效应,康普顿效应及电子对生成)将能量转移给次级带电粒子(电子)。第二步,带电粒子通过原子激发或和电离将能量转移给介质。
8 、 Cema ( 比释能 )
Converted energy per unit mass
It applies to direct ionizing radiation
此处 dEc 是带电粒子在质量为 dm 的材料中碰撞损失的能量,不包括次级电子的损失。
cdEC
dm
Question 3 Please describe the definitions and formulas of
concepts “ Cema” & “Kerma”?
9 、 The relative dominant area of three main effects of photon-media interactions
光子与介质相互作用中三种主要作用相对占优势区域
Photoelectric effect These three effects are other than three actions, so called electromagnetic action,weak action,strong action.
10 “、 4R” concept in RT
Cells be irradiated will experience four occurrences which named 4R.
4R --- Repair 修复 Regeneration 再增殖 Redistribution 细胞周期再分布 Reoxygenation 再氧合
Question 4
What is 4R in radiobiology?
肿瘤 五年生存率(%)kV级 X 射线 高能 X ( γ )射线
霍奇金氏病 30~ 35 70 ~ 75
食管癌 0 ~ 2 8 ~ 16
宫颈癌 35 ~ 45 55 ~ 65前列腺癌 5 ~ 15 55 ~ 60鼻咽癌 20 ~ 25 45 ~ 50膀胱癌 0 ~ 5 25 ~ 35卵巢癌 15 ~ 20 50 ~ 60
视网膜母细胞瘤 30 ~ 40 80 ~ 85精原细胞瘤 65 ~ 70 90 ~ 95睾丸胚胎瘤 20 ~ 25 55 ~ 70扁桃体癌 25 ~ 30 40 ~ 50
物理因素导致放射治疗 5 年生存率的提高
Three aspects in modern RTThree aspects in modern RT
容积调强VMAT
调强 IMRT
适形照射“刀”
常规照射
IGRT(3D KV)
EPID(2D MV)
film胶片
剂量验证
Irradiation techniques
Dose verificationPosition verification
hostservant servant
“If you can’t see it , you can’t hit it
If you can’t hit it, you can’t cure it”
B. Historical Review
1. Experimental aspects2. Theoretical aspects
1.1 In 1895, Roentgen discovered X rays
In 1901, He won the first Nobel Prize
1.2 In 1896, Becquerel discovered radioactive element of uranium
1.3 In July 1898, Madame Curie and her husband got a great success that they discovered the radioactive element, polonium, which Marie named after Poland.
伟大的居里夫妇发现钋
1.4 The discoveries of α 、 β 、 γ rays
Rutherford‘s atomic model (1911)
Historical review 1. Experimental Discovery
Historical review
2. Theoretic Discovery
---Full of seminal ideas
2.1 Microcosmic Scale - Quantum Mechanics 微观尺度-量子力学
10-10mAtom
10-14m(10fm)Nucleus
10-15m(fm)Nucleon
10-18mquark
2~ , ,
hn A E h p k
Wave-Particle Duality, Probbility, Entanglement
D~ћ/mc
,Ei ti tAe Ae E h
•layer of structure
Schödinger- equation (introduce operator & complex number)
Klein-Gordon- equation
Dirac- equation (import spin matrix & Quaternions 四元数 )
非相对论-相对论;时空非对称-时空对称;狄喇克方程,引入自旋自由度(波函数由单分量到多分量)
21( ) 0 (2.01)
2it m
22 2
2( ) 0 (2.02)mt
0 (2.03)imt
E=p2/2m
E→ i∂/∂t, P→ -i∂/∂r
E2=p2c2+m2c4
E=±(p2+m2)1/2
=αpc+βmc2
2.2 High energy - Relativity
High energy particles belong to
Relative territory.
~
The relative particles should suffice 1. Lorentz-transform invariance; 2. Curved space time.
4 810 ~ 10 eV
Nucleus
Particles
8 1010 ~ 10 eV Q+L
1010 eV
1 1P E
E M
P E MFor particles, the criteria to distinguish whether it is a relative particle or not is:
2.3 Particles creating & annihilating — Quantum Field Theory
There are three types of quantum field theories
In 1934 , Pauli and Weisskopf pointed out that just like Maxwell equation, K-G equation as well as Dirac equation are all the field equations.
K-G’s is for scalar field, which spin is most meson
Dirac’s is for rotary field( 旋量场 ), which spin is
Maxwell’s is for vector field, which spin is photon
* 粒子是相应的场的一种激发态,反粒子是相应的复共轭场的一种激发态。不同的场(复共轭场)的激发态代表不同数目的粒子(反粒子)态;场(复共轭场)由激发态变到基态表示相应粒子(反粒子)消灭(湮灭),场(复共轭场)由基态变到激发态表示相应粒子(反粒子)产生
* 场论的‘真空’充满了各种粒子(反粒子)场(复共轭场)的基态
12
1
0
基本粒子的四要素自旋、静质量、电荷量和磁矩
自旋是量子力学的术语,是讨论物质波对称性质的一种表述,并非真的粒子自己在旋转。
从量子理论定义上来讲,自旋半圈后看起来和原来一样的粒子,自旋量子数为二;自旋一圈时的粒子,量子数为一;而自旋两圈才和原来一样的粒子,自旋量子数为二分之一。
自旋本无特定的方向,只有在测量时才显示确定的方向 已发现的粒子中,自旋为整数的,最大自旋为 4 ;自旋为半奇数的,最大自旋为 3/2 。 电子的自旋是 1/2 ,光子的自旋是 1 。
c. The Revolution in Radiotherapy
循证医疗
Highlight some of the technologies
Just like a robot
Tomotherapy( 断层扫描式放疗 ) can irradiate while rotating
Can check position while irradiating
Proton Radiotherapy
LET & RBE
低 LET 射线, RBE值低 (≤1.0) ,高 LET 射线, RBE值高 (≥2.0) 。高 LET 射线的 RBE ,在达 20keV/μm 以上时,随 LET升高而迅速上升,同时 OER下降,但当超过 160keV/μm 时, RBE值反又减小,而 OER下降到 1 。高 LET 射线的RBE大,在细胞存活曲线上体现 D0 值 ( 平均致死量 )低,且其 RBE值随分割照射时的分次剂量大小而改变,即每次剂量越小, RBE值越大。
The PDD comparisons of varies rays
Electronbeam
电子线用于浅表组织的治疗
How to treat moving target?
Movement and deformation
RPM — Real-time Position Management
Respiration synchronised imaging and treatment
The Real-time Position Management™ (RPM) system is a non-invasive, video based system that allows for clean imaging and treatment of lung, breast, and upper abdominal sites.
The RPM system is accurate, easy to use and fast. It is comfortable for the patient and accommodates both breath hold and free breathing protocols.
The problem of RPM
4D real time tracing system 四维实时跟踪放疗
4D Tx delivery “Visualization”:
Internal magnetic marker displacement (Calypso)
Calypso system: response
Next step after RPM
Thank you for your Thank you for your
kind attention !kind attention !