APS医学工程课程介绍部分

1 医学超声仪器原理Principle of Medical Ultrasound Equipment
Q1: What is the ultrasound?
A1: Ultrasound is a kind of high frequency sound waves (more than 20k Hz), belongs to a kind of mechanical wave.
Q2: How ultrasound combined with medicine?
（How clinical application？）
A2: By launching a set of ultrasound machines, ultrasound will be reflected back when encountered the body or tumor.
Doctors on the basis of the reflected sound waves infer the size and the location of the lesion or the tumor.
Q3: How the ultrasound equipment launching ultrasound? How to accept ultrasound? A3: piezoelectric sensor (silicon)
As sound-wave launching components, converts electrical energy to the high frequency vibration振动;
As sound-wave receiving components, vibration cause by reflected sound will be converted to electrical signals.
Q4: Compared with other medical detection (treatment) technology, what advantage does ultrasonic have?
A4: Ultrasonic detecting almost no harm to human body, although it displays the image is not very clear.
Q5: Ultrasonic is how to solve the lesion / tumor / calculus?
A5: By carrying energy, ultrasound can shatter the lesion / tumor / calculus.
Q6: How many types do the ultrasound equipment/medical ultrasounography have? What are their features (function)?
A6: There are three main kinds of ultrasonic instruments .The type-B ultrasonic, the type-M ultrasonic, and the Color Doppler Flow Imaging (CDFI).
Type-B ultrasonic can display the two-dimensional figure, for the fetus.
Type-M ultrasonic can display the movement of the heart
CDFI can show blood velocity, flow and stability.
Q7: What is the component of Ultrasound Equipment?
A7: Both of sound-wave launching component and receiving component is the part of ultrasonic probe (detection). They use the same structure such as Electronic linear array ultrasonic probe. It contains six parts: switch controller, damping pad, matching component, linear array sensor, sound lens, and hull.
Switch controller is designed for focused ultrasound by time-delay circuit.
Time-delay circuit (inductance(inductor) and 3-8 decoder)【图】
Q8: How did you segregate the launching component and receiving component?
A8: segregate circuit.【图】（diode and audion）
Q9: What is the principle of CDFI?
A9: It is basis on Doppler Effect. △f=2f·cosθ·(v/c)
The frequency shift △f of reflected sound can show the velocity；
Red color means the direction of blood cell is face to the ultrasonic probe.
Blue color means the direction of blood cell is reverse to the probe.
Green color shows the stability of the blood. (turbulence flow)
Q10: What is the effect of the matching component?
A10: Between the sensor and the object to keep a necessary distance.
Because the sound field attenuation rule is like this.【图】
2放射治疗设备原理Principle of Radiation Therapy Equipment
Q1: What is the radiotherapy? What is the principle of radiotherapy？
A1: Use of high-energy rays (such as x-ray，ionizing radiation) to treat tumor.
Q2: What are commonly used in radiotherapy equipment?
A2: Kilo-voltage X-Ray therapy apparatus
Cobalt 60 therapy apparatus
Medical linear accelerator（electron ray）
Q3: What is a medical linear accelerator? What is its function?
A3: First，we input higher voltage，for magnetron can generate the high power microwave
Secondly，electronic injector control the number and the speed of electronic into the medical linear accelerator
Thirdly, electronic get energy to accelerate from the microwave in accelerator，to be high-power electron beam.
Finally, the high-power electron beam shoots the Anode target, to produce the ray that we need.
Q5: What is the process（step）of radiation therapy ?
A5: Firstly, confirm the location of the tumor, and choose the way to radiation exposure. (Simulate it) We need avoid other healthy organs.
Secondly, use computer to optimize therapeutic schedule.
Thirdly, Use radiation（ray）to kill tumor (cancer).
3医用X线机系统Medical X-ray Machine System
Q1: What is the medical X-ray?
A1:When the Electronic energy level（state）change ,it will radiated a kind of energy
wave. That is x-ray.
Q2: How does the x-ray generate?
A2: Electronic impacts (shoot) anode target (tungsten) from the cathode. Let it generate ionization and bremsstrahlung radiation, thus radiating x-rays.
Q3: What is the role of the x ray?
A3: Through the body, found the position of the disease.
Q4: What are x-ray features (function)?
A4: The medical x-ray has two models with radiography and fluoroscopy. Both models have some harm to human body.
Radiography is very fast, the film is more clearly, but it has more radiation. It is often used to check the lungs and intestines.
Fluoroscopy is slowly than radiography. It is often used to intervene in operation and physical examination.
Q5: What is the principle of x-ray detection (diagnosis).
A5: Different density organ has different x-ray absorption.
Through the body, the x-ray project in the film. And then, through the observation of film, doctor found the position of the disease. (dark region and bright region)
Q6: What is the advantage of X-ray?
A6: The x-rays have some harm to human body, but it’s far less than CT.
And the x-ray machine is very cheap and simple.
Q7: What are the names of these various x-ray machines? What are the different of clinical application?
A7: Mammography is for breast. We need change the filter so that generate the x-ray which fit human breast.
Dental X-ray unit gives the examination of the teeth. It can give a panoramic x-ray of all the teeth at once. It removes around your head at the section of your teeth. Angiography: Doctor injects contrast media in the blood vessel. This way can enhance the contrast between the blood vessel and background.
Q8: What is CR? What is DR?
A8: DR is digital radiography; CR is computed radiography.
DR is base on A-Si (Amorphous Silicon), x-ray can be converted to electric signal. CR likes detector of CT.
4 CT成像原理与技术（Computed tomography Principles）
Q1: What is the basic of physical principles of CT?
A1: Electronic impacts (shoot) anode target (tungsten) from the cathode. Let it
generate ionization and bremsstrahlung radiation, thus radiating x-rays.
Q2：What is the CT Components（part）？（How many stage does CT have？）
A2: There are three section（stage）：data acquisition, image reconstruction and image display
The data acquisition contains a lot. There are mainly four parts: x-ray frame (tube), filter, collimator and detector.
Q3: What is the Reconstruction algorithms（CT image Reconstruction）？
A3: Detector gets different angles of projection, so that sinogram is formed.
The algorithms that use sinogram to reconstruct object is called reconstruction algorithms.
Reconstruction algorithms includes a lot，such as filtered back-projection(FBP), FT reconstruction and iterative reconstruction.【图】
Iterative reconstruction is used for low dose reconstruction.
Q4: What is the image artifact?
A4: Artifacts are that reconstruction image appears something which does not exist in object.
Q5: How to make the image clearer?
A5: Improve SNR(signal to noise ratio)，Eliminate artifacts, improve HCR(high contrast resolution), and so on.
①Improve SNR: Improve the thickness of scan, because it will improve the signal that detector acquire. This way applies to get the image of smaller different of density. And we also can reduce noise by digital image processing.
②Eliminate artifacts: If we find that there was a line but not cosine(sine), that need be eliminated. Because it will cause the ring artifacts.
③Improve HCR: Reduce the thickness of scan, because it will improve the accuracy. This way applies to get the image of larger different of density, such as lungs and bones because they have high contrast. Reduce the size and interval of detectors. Reduce the size of focal spot of x-ray.
Q6: How the detector to get projection? What is the structure of data acquisition?
A6: The x-ray frame removes around human body, and the opposite detector receives the x-ray which through the human body. Thus how to detector get projection.
Q7: What is the different between the FBP and FT?
A7: FBP is used to star artifacts in back-projection. Before the back-projection, we need processing the projection of that angle with the help of filter. (star artifacts at the center of image)
FT is using Fourier transform to reconstruct the object. 【图】
【BP greatest common divisor at last】
Q8: How is the collimator and detector work?
A8: Collimator, eliminate scattered rays. And detector contains photomultiplier tube. The photons impact the cathode, let it produce a little electron. With the help of electric field to accelerate it, finally the anode of photomultiplier will produce lots of electrons. 【detector: CsI NaI They are chemical elements.】
Q9: What is the function of filter?
A9: Eliminate the frequency which we don’t need.
5 MRI原理与技术（MRI principle and technology）
Q1: What is the basic of physical principles of MRI? (NMR)
A1: MRI is magnetic resonance imaging. The physical principle is called NMR. Firstly, some atoms (such as hydrogen atom) in the static magnetic field produce Larmor precession.
Secondly, when we give it a radio frequency (RF) field, which conform to [formula], NMR will happen. (The spin of atom fall down; RF is a kind of excitation) Thirdly, when the radio frequency field stop, the atom will return to the Larmor precession state, called a relaxation process, it will produce some medical signals, such as T1, T2 and PDW (proton density weighting).
Q2: What kind of image does the MRI produce？How to produce this image？
A2: two-dimensional images at any angle of the plane, even three-dimensional images.
Imaging objects are spatially encoded by gradient magnetic fields.Spatial encoding contains three steps: Slice gradient, Phase gradient and Readout gradient. They let different location of the atomic produce different signal.
Signal receiving coil will decode signal in space k, and with the help of Fourier inverse transform presented in the end.
【公式：y=Acos(ωx+φ)】
Because of the slice gradient magnetic field, we can just let atoms in one plane to produce signal. And with the help of Phase and Readout gradient magnetic field, we can let different location of atoms of this plane generate different signal. In x-direction, different location atom has different ω；in y-direction, different location atom has differentφ. (ωincrease along the x-direction; φincrease along the y-direction)
ωis the frequency of atom-spin; φis the phase-difference of atom-spin.
Q3: What is the space k? How is it work? 【不问不提】
A3: Space k stores the information of image. Near the outside of space k is the high frequency information that determines the HCR of image. The centre of the space k is the low frequency information that determines the SNR of the image.
【追问再说】
Actually the phase gradient field will repeat many times but through different
phase-difference gradient field.【图】Because high phase difference contributes to improve the HCR of image, and low phase-difference contributes to improve the SNR of image.
Q4: What are the different between the MRI and CT?
A4: MRI is based on the principle of NMR phenomenon; but CT is based on the characteristics of X-ray.
MRI has excellent HCR (high contrast resolution).
MRI of the harm to human body is less than CT.
MRI is more expensive.
MRI can get the two-dimensional images at any angle’s plane of body; while CT just can get cross sectional image.
Q5: How to make image clearer? Eliminate artifacts?
A5: If we use high intensity of phase gradient, that will improve the HCR of image.
If we use low intensity of phase gradient, that will improve the SNR of image.
About the movement artifacts, we can use Gating Technique, receive the signal just in calm period.
6 现代检验医学仪器（Medical Laboratory Instruments）
Q1: What kind of the clinical laboratory instrumentation?
A1: hematology analyzer, flow cytometer (FCM), blood gas analyzer, urine analyzer, biochemical analyzer
Q2: What are their purposes?
A2:
①Hematology analyzer: Classify blood cells and counting
Principle: tiny particles through special holes can cause solution resistance of hole change
②Flow cytometer: Fast measure the physical and chemical properties of cell【图】
③Blood gas system: through testing the blood and breath gas, we can analyze the acid-base balance and oxygen state【图】
④Urine analyzer：urine in the reagent with different color causes different light reflectivity，so as to determine the indicators of urine【图】
⑤Biochemical analyzer：Analyze blood and other body fluids by using a set of automation equipments to determine various biochemical indicators【图】Principle：photoelectric colorimetric technique（ Lambert-Beer's Law）
【A=kbc; A→absorbance; k→constant; b→thickness; c→concentration】
7 医用传感器medical sensors
Q1: What kind of medical sensors are there
A1: resistive sensor (capacitive sensor, inductive sensor), piezoelectric sensor,
magnetic sensor, thermoelectric sensor, optical sensors
Q2: What is the principle of these sensors
A2:
①Resistive sensor: When strain gauge changes shape, the resistance will change. This change will be obviously detected by resistive Wheatstone Bridge.
capacitive sensor，inductive sensor：The resistance is replaced by capacitor or inductor and it can improve sensitivity.【图】
②Piezoelectric sensor: Pressure can be converted to electrical signal and output by using piezoelectric sensor.（be used in ultrasound instrument）
③Magnetic sensor: Using the hall element, magnetic field intensity can be converted to electrical signal output.
④Thermoelectric sensor(thermocouple): Basis on Seebeck effect【图】，sensor can sense difference in temperature and Converted to electrical signal output.
⑤Optical sensors: Using the photoelectric effect，the optical signal is converted into electrical signal output.
8 现代医学电子仪器原理与设计Principle and Design of Medical Electronic Instrumentation
Q1: What the principle should be followed when medical electronic instrumentation design?
A1: High CMRR (common mode rejection ratio), such as amplify circuit.
High sensitivity, such as emitter follower/Wheatstone Bridge
Limit the noise (more important than amplifying signal), such as LPF/differential amplifier circuit (zero drift noise) or software processing
Ensure it conform to EMC, energy dissipation circuit
Ensure it conform to safety standards of human body
Q2: What the different between the interference and noise.
A2: Interference: From the outside of the test system
Noise: From the test system, from itself
Q3: What is the EMC? (Explain it)
A3: EMC is Electro Magnetic Compatibility.
On the one hand, it must restrain the interference from outside.
On the other hand, it must restrain itself to interfere others equipment.
Q4: How to design a medical electronic instrumentation
A4:【图】
Signal acquisition, signal preprocessing, signal processing, feedback/control, stimulation, signal calibration, records, data save
For example: In the morning, engineer will use water phantom to check the CT. Signal preprocessing: such as detector of CT
9 Linear Algebra 线性代数
A：In this course, we mainly study what is matrix, how to operation it. Because matrix is the basis of image reconstruction in CT. By the way, we can also use Matlab for matrix operation. It is useful software.
Matrix: be used to solve difficult equations.
10 Complex function and integral transform 复变函数
A: In this course, we have learnt Fourier transform; it is the basis of signal courses, such as DIP, DSP and so on.
11 Probability Theory and Mathematical Statistics 概率论
A: In this course, we mainly study probability distribution such as Gaussian distribution. It is the basis of DIP; especially reduce noise, because noise is random. 【看情况说】We also learnt histogram, with the help of histogram, we can processing the digital image very easy.
10 病理学Pathology 生理学Physiology
Q1: What is the different between the Physiology and Pathology?
A1: They all introduce the human organs simply. But Physiology studies the healthy state of human organs while Pathology studies the unhealthy state, the pathological reaction of organ.
Q2: Do you know what pathological reaction does the organ happen?
A2: The cell will have adaptive changes when it is injured.
But when it breakthrough the limitation, cells can appear damage, and eventually death.
Finally, organs will be in the form of regeneration or fibrous repair to repair themselves.
Q3: I notice your scores of Physiology and Pathology is lower, do you have any reasons about that?
A3: Because the pathology and Introduction to Clinical Medicine involves knowledge is too complicated, and this course don’t have many relationships with my major (research direction).
【prepare】肠道intestinal tract 胃stomach 肌肉muscle 心脏heart大脑brain 肺lungs乳房breast 胸腔chest 骨bones
13 An Overview of clinical Medicine 临概systematic anatomy 系解
Q1: What knowledge does An Overview of clinical Medicine introduce to you?
A1: Simple to outline some of the human body system：Motor system, digestive
system, respiratory system, blood circulatory system, nervous system, urinary system, reproductive system, endocrine system
Q2: What did you know from the systematic anatomy?
A2: The name of bones and muscles. Outline the organs human have and function of them. Such as intestinal tract belongs to gas-containing organs, so we can use ultrasound instrument for diagnosis. And bone is a kind of high density organ, so we can use x-ray for diagnosis.
14 The Recognition and Nursing of common clinical symptoms 临床症状识别
Q1: If patient have some clinical symptoms, how to diagnose it? Use what medical facility?
A1: If we want to recognize/diagnose clinical symptoms, firstly we need know the location of symptoms and what system it belongs to.【临概、系解也可套用】Such as headache, because it belongs to nervous system and our brain have many complex structures, so we need use CT or MRI. (The HCR of MRI is good than CT, but expensive)
Such as cough, because it belongs to respiratory system and the density difference between the lungs and bone is high enough, so we can use x-ray. But if there maybe has a tumor, we have to use CT for diagnosis.
Secondly, we need ensure the period of disease. Such as cancer, if it is early period, we just need use medical instrument to ensure the location and size of tumor and cut it by operation. But if it is later period, maybe we must use radiation therapy. 【病理也可套用】
【prepare】Because it is optional course and do not have many relationship with my major, so we just need to know the outline of it. 【案例分析也可套用】
15 Legal Analysis of Typical Case about medical
A: In Wuhan, there was a woman, be checked by CT and found a shadow behind breastbone. It was doubted a tumor and use radiation therapy for a long time. Finally, the hospital found it is misdiagnosed, it’s not tumor. And hospital has to refund to that patient. But doctor didn’t have fault although it’s misdiagnose. Because that shadow, nobody can insure it is a tumor or not, doctor just could say “maybe is a tumor, maybe not”. So as a biomedical engineer, we should make the medical instrument better for reducing the artifacts and make the image clearer.
16 电子技术试验Electric Technology Experiment
Q1: What experimental/laboratory apparatus did you use?
A1: Signal generator，Oscilloscope, Circuit element (resistance capacitor inductor diode audion)
Q2: What experiment did you do?
A2: Emitter follower, Differential amplifier, integrated operational amplifier
Q3: What did you learn from these experiments?
A3:
①Emitter-follower: Let the output voltage follow the input voltage linear change in a wide range
②Differential-amplifier: Amplify different-mode signal, restrain common-mode signal
③Integrated operational amplifier: Use it to proportion, addition, subtraction, integral operation
17 C Language Programming 面向对象程序设计object oriented programming
Q1: What is the different between the C language and C++?
A1: c++ can run most of c code while c cannot run c++ code.
C is function-driven while c++ is object-driven.
In the case C, the program is formulated step by step, each step is processed into detail. While in c++, the base elements are first formulated which then are linked together to give result to larger system.
Q2: Can you write a program?
A2: If we want to compare figure a and b, and put out the maximun.
If we use c language:
#include<stdio.h>
main ()
{
int a,b,max;
printf(“input 2 numbers :”);
scanf(“%d%d”,&a&b);
if (a>=b) max=a;
else max=b;
printf(“the maximum is :%d”,max);
}
If we use c++ language:
#include<stdio.h>
int max(int a,int b)
{
if a>=b return a;
else return b;
}
main()
{
cout<<“input 2 numbers:”;
int a,b;
cin>>a>>b;
cout<<“the maximum is :”<<max(a,b);
}
附：%d is a kind of data type
a b max is the name of where store the data.
18 Quality System and Regulations of Medical Device
A: According to Chinese law, the supervision for quality of the medical instruments in different stage is the responsibility of different government departments. The stages of registration and production are the responsibility of CFDA; the stages of installation and usage are the responsibility of MOH. The organization which tests the quality of the medical instruments must be accredited by the CNAS.
About the classification of the medical instruments and laws, regulations (such as GB9706 and YY0505)are constantly updated by the government. So we just need log into the website of CFDA and MOH, and then we can get the latest information about the instrument.
Q1: What is different between the Quality System and Testing Technology?
A1: Quality System of Medical Deice pays attention to the law and regulations about medical device. While Testing Technology of Medical Equipment pays attention to how to test parameters and test what parameters of medical equipments.
19 Testing Technology of Medical Equipment
A: There are common requirement and special requirement about the medical instruments. Under normal conditions, we consult handbook such as Security manual to test the medical equipment.
About common requirement, for example“test in single fault condition”. Firstly, we need to make a failure (disconnect the protective earthing line or input a interference signal), and then testing instrument is still safe to human body.
About special requirement, for example“the voltage of x-ray tube”, we usually use “Non-intrusive testing of the tube voltage”. Use different thickness of the filter and the radiation detector. Under the condition of different thickness of filter, record the corresponding radiation attenuation degree. Finally by corresponding relation, we can know the voltage of the X-ray tube.
【prepare】
“CT radiation dose testing” Pencil ionization chamber
Through CTDI to shows radiation dose of CT
“HCR of CT” phantom of line pair
“Testing the thickness of CT scan” phantom of sheetmetal
20 Technical Drawing
Three view drawing (top view, front view, side view) Cross-section view
Diameter Length Width Height。