Biomedical Electronics (PDF) By J.F.Khan Size: A4, Total pages 240 Download this book from : www.chinttanpublications.in

1. TABLE OF CONTENTS
i
TABLE OF CONTENTS
1 BIOMEDICAL ELECTRONIC CHARACTERISTICS AND MEASUREMENT PROBLEMS.................... [1-10]
1.1 System configuration .........................................................................................................................1-1
1.2 Basic characteristics of measuring systems..........................................................................................1-2
1.2.1 Static characteristics ..............................................................................................................1-2
1.2.2 Dynamic characteristics .........................................................................................................1-5
1.3 Second order systems ........................................................................................................................1-6
1.3.1 Frequency response ...............................................................................................................1-7
1.4 Transducers.......................................................................................................................................1-8
1.5 Problems faced when measuring a human body ...................................................................................1-9
Exercises.........................................................................................................................................1-10
2 THE BIOELECTRIC POTENTIAL.........................................................................................................[2-8]
2.1 Resting and action potentials ..............................................................................................................2-1
2.2 Propagation of action potentials ..........................................................................................................2-3
2.3 The bioelectric potentials – ECG........................................................................................................2-3
2.3.1 Electrode theory ....................................................................................................................2-4
2.3.2 The electroencephalogram (EEG)...........................................................................................2-6
Exercises...........................................................................................................................................2-8
3 TRANSDUCERS IN MEDICAL INSTRUMENTATION ..............................................................................[3-8]
3.1 Electrode transducers.........................................................................................................................3-1
3.1.1 The surface electrode.............................................................................................................3-2
3.1.2 Half-cell potential and equivalent circuit elements ...................................................................3-4
3.1.3 The needle electrodes.............................................................................................................3-6
3.1.4 Bio-signal conditioners - design considerations........................................................................3-7
Exercises...........................................................................................................................................3-8
4 BASICS OF CARDIOVASCULAR SYSTEMS.........................................................................................[4-12]
4.1 The heart and cardiovascular system...................................................................................................4-1
4.2 The heart...........................................................................................................................................4-4
4.3 Blood pressure...................................................................................................................................4-7
4.4 Heart sounds .....................................................................................................................................4-9
4.5 Blood flow ......................................................................................................................................4-10
Exercises.........................................................................................................................................4-12
5 BLOOD PRESSURE AND BLOOD FLOW MEASUREMENTS .................................................................[5-16]
5.1 Measurement of blood pressure ..........................................................................................................5-1
5.2 Indirect method .................................................................................................................................5-1
5.3 Direct method of blood pressure measurement electronic manometry-catheterization method.................5-4
5.3.1 Measurement at the site..........................................................................................................5-5
5.4 Ultrasonic blood pressure measurement ..............................................................................................5-5
5.4.1 Ultrasound techniques in blood flow measurement...................................................................5-7
5.4.2 Ultrasonic blood flow meters..................................................................................................5-8

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5.4.3 Magnetic blood flow meters .................................................................................................5-11
5.5 Phonocardiograph............................................................................................................................5-14
5.6 Echocardiography............................................................................................................................5-15
Exercises.........................................................................................................................................5-16
6 ELECTROCARDIOGRAPHY AND STRESS TEST SYSTEM....................................................................[6-22]
6.1 Electrocardiogram .............................................................................................................................6-1
6.2 ECG lead and waveform configurations ..............................................................................................6-2
6.3 The ECG machine .............................................................................................................................6-6
6.4 Three channel recorders.....................................................................................................................6-8
6.5 Vector electrocardiographs.................................................................................................................6-8
6.6 Stress test systems (treadmill test).......................................................................................................6-9
Exercises.........................................................................................................................................6-22
7 PACEMAKER AND DEFIBRILLATOR ................................................................................................[7-16]
7.1 Pacemakers.......................................................................................................................................7-1
7.1.1 Pacemaker classifications .......................................................................................................7-2
7.2 Ventricular synchronous demand pacemaker.......................................................................................7-3
7.2.1 Asynchronous cardiac pacemaker (free running)......................................................................7-4
7.2.2 Demand-type synchronous pacemaker ....................................................................................7-4
7.2.3 Atrial-synchronous cardiac pacemaker....................................................................................7-4
7.2.4 Programmable pacemaker......................................................................................................7-5
7.2.5 Batteries for pacemaker..........................................................................................................7-7
7.3 Defibrillators .....................................................................................................................................7-8
7.4 Defibrillator machine .......................................................................................................................7-11
7.4.1 The inverter and EHT circuit ................................................................................................7-12
7.4.2 The regulator and comparator circuit.....................................................................................7-12
7.4.3 The control circuit ...............................................................................................................7-13
7.4.4 The synchronizing circuit.....................................................................................................7-14
Exercises.........................................................................................................................................7-16
8 LABORATORY INSTRUMENTS..........................................................................................................[8-22]
8.1 Clinical laboratory equipment.............................................................................................................8-1
8.1.1 The blood..............................................................................................................................8-1
8.2 Tests on blood cells ...........................................................................................................................8-2
8.2.1 Methods of cell counting........................................................................................................8-3
8.3 Blood gas analysers ...........................................................................................................................8-6
8.3.1 Acid base balance..................................................................................................................8-6
8.3.2 Blood pH measurement..........................................................................................................8-7
8.4 Biochemical transducers ....................................................................................................................8-7
8.4.1 Measurement of gas distribution .............................................................................................8-9
8.5 Chemical tests .................................................................................................................................8-13
8.5.1 Colourimeter or filter photometer .........................................................................................8-16
8.5.2 Flame photometer................................................................................................................8-17
8.5.3 Spectrophotometer...............................................................................................................8-19
8.5.4 Autoanalysers......................................................................................................................8-20
Exercises.........................................................................................................................................8-22

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9 DISPLAY SYSTEMS ..........................................................................................................................[9-18]
9.1 Oscilloscopes for biomedical measurements........................................................................................9-1
9.2 CRO used in medical equipment-cardioscope ......................................................................................9-2
9.2.1 Non fade oscilloscopes...........................................................................................................9-2
9.3 PMMC galvanometer movements .......................................................................................................9-3
9.3.1 PMMC writing systems..........................................................................................................9-5
9.4 Instrumentation tape recorders............................................................................................................9-6
9.4.1 Recorders..............................................................................................................................9-6
9.4.1.1 Strip chart recorders................................................................................................9-7
9.4.1.2 X-Y recorders........................................................................................................9-13
9.4.1.3 Ultraviolet recorders.............................................................................................9-15
9.5 Beside and central monitoring systems..............................................................................................9-16
9.5.1 Beside monitors...................................................................................................................9-16
9.5.2 Central monitors ..................................................................................................................9-18
Exercises.........................................................................................................................................9-18
10 X-RAYS .....................................................................................................................................[10-18]
10.1 Introduction ....................................................................................................................................10-1
10.2 The X-ray tube.................................................................................................................................10-5
10.3 The nature of X-rays........................................................................................................................10-7
10.4 X-ray absorption ..............................................................................................................................10-8
10.5 Tissue contrast.................................................................................................................................10-8
10.6 Units of X-ray radiation....................................................................................................................10-9
10.7 X-ray machine .................................................................................................................................10-9
10.7.1 Fluoroscopic system .......................................................................................................... 10-11
10.8 Computer tomography (CT) ........................................................................................................... 10-13
10.8.1 Rotating type of scanners................................................................................................... 10-16
10.9 Positron emission tomography (PET).............................................................................................. 10-17
Exercises....................................................................................................................................... 10-18
11 PATIENTS SAFETY .......................................................................................................................[11-8]
11.1 Effect of electric current on the body ................................................................................................11-1
11.2 Isolated patient circuits ....................................................................................................................11-3
11.3 Procedure for electrical safety testing of medical equipments at the emergency care research
institute (USA).................................................................................................................................11-6
11.3.1 Physical examination ...........................................................................................................11-7
11.3.2 Operational tests..................................................................................................................11-8
Exercises.........................................................................................................................................11-8
12 DIAGNOSTIC MEDICAL EQUIPMENTS.........................................................................................[12-14]
12.1 Introduction ....................................................................................................................................12-1
12.2 Production of ultrasound ..................................................................................................................12-1
12.3 Impedance matching........................................................................................................................12-2
12.4 Transducer selection ........................................................................................................................12-2
12.5 Absorption and attenuation of ultrasound energy ...............................................................................12-3

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12.6 Scan modes of ultrasound imaging....................................................................................................12-4
12.7 Pulsed doppler systems ....................................................................................................................12-5
12.8 Magnetic resonance imaging (MRI)..................................................................................................12-6
12.8.1 Magnetic resonance phenomenon .........................................................................................12-6
12.8.2 Magnetic resonance spectroscopy in-vivo..............................................................................12-7
12.8.3 Magnetic resonance imaging ................................................................................................12-8
12.8.4 Magnetic relaxation and MRI parameters...............................................................................12-8
12.8.5 Magnetic field strength and gradients.................................................................................. 12-10
12.8.6 Pulse sequences................................................................................................................. 12-11
12.8.7 Imaging processes ............................................................................................................. 12-11
12.9 The MRI machine .......................................................................................................................... 12-11
12.10 Skin temperature measurements...................................................................................................... 12-14
Exercises....................................................................................................................................... 12-14
13 LASERS IN MEDICINE ..................................................................................................................[13-8]
13.1 Introduction ....................................................................................................................................13-1
13.2 Laser classification ..........................................................................................................................13-1
13.3 Basic concepts.................................................................................................................................13-1
13.4 Types of lasers ................................................................................................................................13-3
13.4.1 Insulating solid lasers...........................................................................................................13-3
13.4.2 Insulating crystal lasers........................................................................................................13-4
13.4.3 Excimer lasers.....................................................................................................................13-5
13.4.4 Gas lasers............................................................................................................................13-5
13.4.5 Solid-state PN junction lasers...............................................................................................13-6
13.5 Applications of lasers in ophthalmology............................................................................................13-7
13.5.1 Photo thermal applications ...................................................................................................13-8
Exercises.........................................................................................................................................13-8
14 NERVOUS SYSTEM.......................................................................................................................[14-8]
14.1 Electroencephalography...................................................................................................................14-1
14.2 EEG electrodes and the 10.20 system................................................................................................14-3
14.3 EEG amplitude and frequency bands.................................................................................................14-4
14.4 The EEG system: simplified block diagram.......................................................................................14-7
Exercises.........................................................................................................................................14-8
15 HEMODIALYSIS ...........................................................................................................................[15-6]
15.1 Basic renal physiology .....................................................................................................................15-1
15.2 Renal failure....................................................................................................................................15-2
15.3 Peritoneal dialysis ..........................................................................................................................15-3
15.4 Hemodialysis ..................................................................................................................................15-3
15.5 The hemodialysis machine ...............................................................................................................15-4
Exercises.........................................................................................................................................15-6
Laboratory experiment 1 ................................................................................................................. [1-6]
Laboratory experiment 2 ............................................................................................................... [1-20]
Laboratory experiment 3 [Heart rate monitor laboratory]................................................................... [1-2]
Laboratory experiment 4 ............................................................................................................... [1-10]
Laboratory experiment 5 [study of pulse oximeter] ........................................................................... [1-5]