Methods in Biomedical Engineering Research 詹曉龍 長庚大學電機系

Transcription

1 Methods in Biomedical Engineering Research 詹曉龍 長庚大學電機系

2 Topics Related to Electrical Engineering and Computer Science Biomedical Engineering Medical Instrumentation Monitor and Measure Physiological Event Signal Processing Detect, Classify and Analyze Biomedical Signals BioMEMS Build Micro Electro- Mechanical System on a Chip Medical Imaging Display Anatomical Details and Physiological Function Rehabilitation Engineering Provide Therapeutics and Aids Devices for the Disabled Bioinformatics Medical Informatics Build Medical Information and Decision Support Systems Solve Computational Problems in Molecular Biology Methods 2

3 Bioinstrumentation Outputs Measurand Sensor Signal Signal conditioning processing Data displays Effector Feedback Data storage Data communication John G. Webster, Bioinstrumentation, John Wiley & Sons, Methods 3

4 Evolution of Medical Electronics First Electrocardiograph (ECG) by William Einthoven in 1903 Patient Monitors ECG Holter Biopotential chip Methods 4

5 Ultrasound Methods 5

6 M2A Capsule Inside the M2A Capsule 1. Optical dome 2. Lens holder 3. Lens 4. Illuminating LEDs (Light Emitting Diode) 5. CMOS (Complementary Metal Oxide Semiconductor) imager 6. Battery 7. ASIC (Application Specific Integrated Circuit) transmitter 8. Antenna Methods 6

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8 Origin of biopotentials Na + Cl - Extracellular domain Phospholipid p bilayer Intracellular domain K + Methods 8

9 Action potential Na + Na Outside cell Plasma membrane Inside cell K + K + 1 Resting phase 3 Repolarizing phase Na + Na K + 2 Depolarizing phase 4 Undershoot phase K + rane potential (mv) Memb 100 t Methods 9

10 Active channel: sodium-potassium pump Remove 3 Na + for every 2 k + outside K+ Na+ inside K+ Na+ M. Bear et al, Neuroscience: exploring the brain, Lippincott Williams & Wilkins, Methods 10

11 Origins of electromyography Methods 11

12 Prosthesis control using myoelectric signal (Myoelectric Control System at University of New Brunswick, Canada) Methods 12

13 EMG during different movements Methods 13

14 Compliant grasp in a myoelectric hand prosthesis Okuno et al, IEEE EMB Methods 14

15 Retinal Prosthesis implant system Methods 15

16 Multiple-unit unit Artificial Retinal Chipset (MARC) Methods 16

17 Early Visual System Hyperpolarized by light flash Signal inverted leading to depolarization Peter Dayan and L.F., Theoretical Neuroscience, MIT Press, G2 fires while light on, and G1 fires when turn off Methods 17

18 Pathway form retina through LGN of thalamus to primary visual cortex Peter Dayan and L.F., Theoretical Neuroscience, MIT Press, Methods 18

19 Cerebrum (Frontal,Parietal,Temporal and Occipital lobes) From JJ Carr, Introduction to Biomedical Equipment Technology, Prentice-Hall, Methods 19

20 Brain Cerebrum ( 大腦 ) Thalamus ( 丘腦 ) Sensory and motor system Human behaviors... Hypothalamus ( 丘腦下部 ) Autonomic nervous system Temperature regulation Water and electrolyte balance Behavior response to emotion Endocrine control Sexual response... Medulla Oblongata ( 延腦 ) Vital centers that regulates heart rate, respiratory rate, blood pressure, blood vessel, etc. Cerebellum ( 小腦 ) Coordinating skeletal muscles and impulses from cerebral cortex M. Bear et al, Neuroscience: exploring the brain, Lippincott Williams & Wilkins, Methods 20

21 Electroencephalogram (EEG) M. Bear et al, Neuroscience: exploring the brain, Lippincott Williams & Wilkins, Methods 21

22 Axon ( 軸突 ) to synapse ( 突觸 ) via neurotransmitter Methods 22

23 Electroencephalogram (EEG) rhythms Methods 23

24 EEG changes in sleep Methods 24

25 Lempel-Ziv complexity Methods 25

26 EEG waveform recorded from one patient under sevoflurane in different states LZ complexity awake state intermediate state asleep state Methods 26

27 Estimation of depth of anesthesia by EEG/AEP EEG monitoring Audio evoked potential monitoring ing Methods 27

28 EEG spikes or abnormal waveform in epilepsy John G. Webster, Medical Instrumentation, application and design, 3rd Ed., Houghton Mifflin, Methods 28

29 EEG electrode placement Methods 29

30 Multichannel EEG recodeings: Neuroscan TM Methods 30

31 Monopolar measurements Methods 31

32 Bipolar measuremesnts Methods 32

33 Monopolar montage Epilepsy spikes Biopotentials 33

34 Bipolar montage Epilepsy spikes Biopotentials 34

35 Brain machine interface (BMI) 圖文摘自隨心而動..以意念操控機器, 科學人,12 月號, 2002 Methods 35

36 Brain machine interface (BMI) 有朝一日, 腦機界面將可幫助因脊髓受傷導致上下肢癱瘓的病人 將微金屬絲組成的微小陣列植入腦中好幾個運動皮質區域, 並與頭骨上的神經晶片連結 病人以想像的方式, 使其癱瘓的手臂以某種方式移動, 好比說伸手去拿桌上的食物, 該晶片能把這種意念轉換成一連串無線電頻率的訊號, 以無線傳輸方式送給掛在輪椅後頭以電池操作的背包式小型電腦 該電腦會將訊號轉換成動作的指令, 並以無線方式傳送到植在病人手臂上的另一個晶片 這第二個晶片會刺激控制手臂肌肉的神經, 讓手臂產生適宜的動作 除此之外, 背包裡的電腦也能隨病人的意願, 直接控制輪椅的馬達及方向控制器, 讓輪椅朝她想要去的地方而行 電腦也可以傳送訊號給機械手臂 ( 如果病人失去她原來的手臂 ), 或是接在輪椅上的機械手臂 杜克大學的沃爾夫製造了一個如下圖所示的神經晶片及背包的原型 圖文摘自隨心而動..以意念操控機器, 科學人,12 月號, 2002 Methods 36

37 Brain computer interface (BCI) Gerwin Schalk, BCI2000: A General-Purpose Brain-Computer Interface (BCI) System, IEEE Trans. BME, 2004 Methods 37

38 Heart and electrocardiogram (ECG, EKG) Methods 38

39 ECG features R R-R interval R P P-R interval T S-T Q S interval Q-T interval U QRS interval P wave : Atrial depolarization QRS complex : Ventricular depolarization T wave: Ventricular repolarization U wave : Slow repolarization of ventricular muscle R-R : Heart period P-R : Conduction delay in the AV-node Q-T, S-T : Ventricular repolarization time Methods 39

40 Relation of different-lead ECG Einthoven triangle From WJ Tompkins, Biomedical Digital Signal Processing, Prentice-Hall, Methods 40

41 ECG measurement using chest leads From JJ Carr, Introduction to Biomedical Equipment Technology, Prentice-Hall, Methods 41

42 ECG at chest leads Methods 42

43 12-Lead ECG Precordial leads: V 1 -V 6 Einthoven leads: I, II & III Goldberger augmented leads: V R, V L &V F Methods 43

44 Cardiac arrhythmia: premature ventricular contraction (PVC) John G. Webster, Medical Instrumentation, application and design, 3rd Ed., Houghton Mifflin, Methods 44

45 Life-threatening arrhythmia Ventricular cua Tachycardia da Ventricular fibrillation Methods 45

46 Detecting VT and VF by TCI Thaker et al, IEEE Trans. Biomed. Eng Methods 46

47 Threshold crossing interval (TCI) TCI ( N 1) 1000 T 2 T1 T 2 T3 T3 T 4 Methods 47

48 Detecting VT and VF by TCI Methods 48

49 Lempel-Ziv complexity ( 複雜度 ) Methods 49

50 Detecting Ventricular Tachycardia and Fibrillation by Complexity Measure (Xu-Sheng Zhang, et al, 1999) window length 3 s 5 s 7 s Methods 50

51 ST-segment elevation John G. Webster, Medical Instrumentation, application and design, 3rd Ed., Houghton Mifflin, Methods 51

52 ST-segment depression (mostly in myocardial ischemia) Methods 52

53 Cardiac pacemaker 竇房結 房室結 左右束分支 中膈 Methods 53

54 Physiological cardiac pacemaker Automatically adjust heart rate to match level of activity E. Park, St. Jude Medical Methods 54

55 Electrode-tissue tissue interface Methods 55

56 Electrode-electrolyte electrolyte interface Ion-electron exchange between electrolyte and electrode cause half-cell potential Methods 56

57 Half-cell potentials at 25 0 C, referenced to hydrogen electrode (near zero half-cell potential) Methods 57

58 Silver/Silver chloride (Ag/AgCl) electrode Low-polarization electrode AgCl quickly saturates and comes to equilibrium Ag Ag Ag Cl e AgCl HL Electrodes Chan, EE, 58 CGU Methods 58

59 Equivalent circuit for a biopotential electrode Half-cell potential Resistance of electrolyte Electrode-electrolyte interface and polarizing effect Methods 59

60 Micromachined dry electrode Gris et al, IEEE Trans. BME, 2001 Methods 60

61 Micromachined dry electrode (cont.) Gris et al, IEEE Trans. BME, 2001 Methods 61

62 Micromachined dry electrode (cont.) Gris et al, IEEE Trans. BME, 2001 Methods 62

63 ECG measurement without conductive contact Lim et al, IEEE Trans. BME, 2006 Methods 63

64 ECG without conductive contact (cont.) Lim et al, IEEE Trans. BME, 2006 Biosensors 64

65 Bridge circuit Wheatstone bridge circuit Precise resistance meaurement Balanced bridge Vab = 0 c R R R R a R 1 R 5 R 2 b R 3 R 4 d Methods 65

66 Thermistor sensing by bridge circuit Thermistor sensing by bridge circuit bt e a S S R V V V V b ) ( 2 S R V V V V b a o The size of thermistor can be as small as 0.5 mm diameter. Methods 66

67 Thermisitor application Tidal air Temperature detector Manual reset Auto Filter, reset Integrator, Audiofrequency and limiter reset amplifier, limit, and oscillator Methods 67

68 Strain guage ( 應變規 ) L A L L A L A L 壓力 A A (R R) L L A A 拉力 Methods 68

69 4-element strain guage sensor R1 R3 R 3 V s R1 R 4 R 2 R 4 R 2 V out (a) V out V ( R) R (b) Methods 69

70 Strain guage application: force measurement Methods 70

71 Strain guage application: respiration measurement Electrical conductive material Flexible tubing Lead Measure the displacement of chest and abdominal due to respiration Their difference can be used to estimate respiratory volume Methods 71

72 Suggested Journals (1) Annals of Biomedical Engineering Artificial Intelligence in Medicine Computers in Biology and Medicine i Computer Methods and Programs in Biomedicine Medical and Biological Engineering and Computing Medical Engineering and Physics Medical Image Analysis Physiological Measurement Ultrasound in Medicine and Biology Methods 72

73 Suggested Journals (2) IEEE Trans. on Biomedical Engineering i IEEE Trans. on Biomedical Circuits and Systems IEEE Trans. on Information Technology in Biomedicine IEEE Trans. on Medical Imaging IEEE Trans. on Neural System and Rehabilitation Engineering IEEE Engineering in Medicine and Biology Magazine Methods 73

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79 下載所需之論文 PDF Methods 79

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83 Journal only Methods 83

84 有 727 篇論文 Methods 84

85 Reference John Enderle, Susan Blanchard, Joseph Bronzino, Introduction to Biomedical Engineering, Academic Press, John G. Webster, Medical Instrumentation, application and design, 3 rd Ed., Houghton Mifflin, Joseph J. Carr, John M. Brown, Introduction to Biomedical Equipment Technology, Pearson Education, 生物醫學工程導論, 滄海書局,2008. 黃豪銘, 醫用電子學, 高立圖書,2010. Methods 85