Electronics Biomedical Instrumentation – Part II – Unit 1
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 1
Unit 1: The defibrillator
In the United States, hundreds of thousands of person die of sudden cardiac
arrest each year. If they could be treated with a defibrillator within one minute of
attack, 80% would have an increased chance of survival. However If this treatment
is delayed by only ten minutes, the statistic fall from 80% to 15%, thus illustrating
how important the defibrillator is, and how important it is to have it available to
the general population.
A defibrillator is an electronic device that creates a sustained myocardial
depolarization of a patient’s heart in order to stop ventricular fibrillation or atrial
fibrillation. These fibrillations occur because ectopic, or out-of-place, stimulus
sites take place in the heart and cause a disorganized cardiac muscle contraction.
When this defibrillation happens to the ventricles, it causes a drastically
reduced cardiac output of blood flow and result in death in a few minutes. An
atrial fibrillation causes reduced cardiac output but is usually not fatal. The D.C
defibrillators must have a mechanism for adjusting the energy level, by controlling
either the amplitude or the duration of the defibrillator pulse. A schematic of the
D.C defibrillator like that introduced by Bernard Lown in 1962 is given in Figure
1. When the switch is in the charge position, current flows through the diode in
one direction and charges the capacitor to its peak value, Vp. The voltage Vp can
be varied by changing the setting on the varactor. The energy stored in the
capacitor and available for defibrillations, Wa, is W
a
= ½.CV
2
p
.
Therefore the energy available from the defibrillator is varied by the
varactor setting.
The defibrillator pulse is delivered by placing paddles covered with an

It causes a drastically reduced ….
4. They may be placed…
5.
This causes the current …
TASK 3
Fill in the blanks from the words given sometimes more than one way apply
(change if necessary).
pediatric for example defibrillator stop
therefore available use reduce
This discharge switch is usually mounted on the paddle. It is important that
the attendants using the defibrillator avoid having the pulse pass through
their own bodies. electrode gel on the paddle handle could provide a path
for the defibrillation pulse through on arm of the attendant and through the heart to
the other arm. An attendant touching the patient is likewise in danger of a shock.
Because of the surface resistance, the defibrillator pulse may be
delivered to the open heart using paddles from 4 to 5 cm in diameter, and the
voltage levels may be reduced by one third. For patients, the external
paddles are approximately 5 cm in diameter and energy levels of about 50 J are
delivered.
Defibrillation is indeed a hazardous procedure, since it involves
the heart, and if applied incorrectly, it could induce fibrillation in a normal
heart. it is essential that a diagnosis be made by trained specialists to
ensure that the patient needs the treatment before it is initiated. In order to reduce
this risk, and to make the defibrillator . For more cardiac arrest
victims more quickly, diagnostic circuitry is used to assess that a fibrillation is in
fact occurring before the defibrillation pulse is applied to a patient. This then
makes it safe for attendants with less training to
the defibrillator.
Electronics Biomedical Instrumentation – Part II – Unit 1
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 3

intensity in watts per square meter is adjusted by the x-ray tube filament
current.
3. Robots are better at this task, not because they are faster or cheaper than
humans, but because they work in a place where humans cannot.
4. When robots malfunction, it is usually due to mistakes in the programming
or the design.
Exercise 2: Combine the following ideas using connectives introducing cause.
Electronics Biomedical Instrumentation – Part II – Unit 1
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 4
Example:
 Air pollution
 Deterioration of substances.
1. a. Many people do not explore new software
b. They are comfortable with what they already have (because)
2. a. The increase in efficiency of diff amp
b. A reduction in the cost of diff amp, from $ 350 to about 35 cents (lead to).
3. a. Cardio version is used in circumstances where the heart is still pumping.
b. Some kill is required to prevent the defibrillating pulse from causing
fibrillation due to incorrect timing (since).
4. a. Deterioration of the Reagent Strip test areas.
b. Exposure to light, ambient moisture or heat (due to).
Electronics Biomedical Instrumentation – Part II – Unit 2
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 5
Unit 2: Medical X-Ray equipment
TASK 1
Choose one correct word or phrase given below to complete each of the following
sentences.
impulse diagnosis properly functional electron beam
1. His willingness to act on and be diverted from the task at hand
drove him to investigate further.

Over the years x-ray equipment has been continually improved major
engineering objectives have been to.
- Improve the quality of the image.
- Heighten the contrast between different tissues.
- Improve size resolution.
- Minimize the dose of x-rays used on the patient.
The X – Ray tube
The x-ray tube is simply a glass – enclosed vacuum tube diode consisting
of a cathode that thermally emits electrons and an anode that attracts these
electrons. A functional diagram of an x-ray tube is given in Figure 1, which shows
a filament source voltage V
F
causes a current I
f
to flow through the filament coil,
heating the cathode metal. Electrons in the cathode are boiled off the metal into
the vacuum. In an x-ray the anode voltage V
A
is high enough that these electrons
are swept across to the anode and form the beam current, I
B
. V
A
on the tube is very
high, on the order of 100 KV. This high voltage impels the electron to a very high
velocity. Approximately 1% of the electrons upon entering the anode collide with
atoms and produce x-rays. The x-rays then pass through the tube into space.
TASK 2
Now read the text and decide whether the following sentences are true (T) or
false (F).

such as xenon, sealed at both ends, and having two conductors, forming a
capacitor on the sides.
b. An x-ray entering the chamber ………………… a xenon atom, causing it
to migrate to the capacitor plate, and causing a current in the high-voltage
lead.
c. As voltage V is increased, the ………………… have secondary collisions
and produce more …………………
4. Amplify, amplified, amplifier.
a. A set of plates ………………… the electron beams by a process of
secondary emission.
b. The output current through R
2
is thus ………………… and may be
detected with a differential amplifier.
5. Localize, location, locate
a. The numbers in the matrix correspond to the attenuation of
………………… on a tissue slice.
b. These medicines are typically absorbed by the organ and emit radiation that
can be detected and …………………
c. Instrumentation and components that detect, measure, and
………………… radioactive medicines are described.
Electronics Biomedical Instrumentation – Part II – Unit 3
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 8
Unit 3: The microprocessor – based equipment
The vast increase in the use of medical equipment was driven by the
invention of the transistor in 1948, and by the subsequent development of solid-
state electronics, which made possible the small dedicated computer. The
importance of the computer in medical equipment increased rapidly in the 1970s,
in particular with the invention of the computer tomography (CT) scanner, an
instrument that would be virtually impossible without dedicated computers. Many

Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 9
2. The importance of the computer in ………………… equipment increased
rapidly in the 1970s.
3. Many types of medical equipment are ………………… by the
incorporation of ………………… computers.
4. At present, a million ………………… can be fabricated on a chip.
5. Microprocessors are used, …………………, to do signal processing on an
ECG waveform.
TASK 2
Read the text and decide whether the following statements are true (T) or
false (F) in relation to the information in the text.
1. In particular with the invention of the computer tomography (CT) scanner,
an instrument that would be virtually impracticable without dedicated
computers.
2. The dedicated computer has always been an irreplaceable element for
magnetic resonance images.
3. By 1970 manufactures could fabricate a thousand transistors on a chop
about one square inch in size.
4. At present, a million gates can be fabricated on a chip, which means that
comparatively powerful computer once costing one or two thousand dollars
is now ready for about 10 dollars.
5. Microprocessors are only used to do signal processing on an ECG
waveform.
TASK 3
Look back in the text and find the reference for the words in italics.
1. An instrument that would be virtually…
2. They work fine without them ….
3. For
them the dedicated computer …
4.

Ultrasonic Imaging Equipment
Ultrasonic voltage generator in Ultrasonic Imaging devices hits the
piezoelectric transducer with a short pulse and causes it to oscillate at its resonant
frequency. It is also possible to use a pulse – modulated generator to drive the
piezoelectric crystal. The pulse generated would be long compared to the period of
the 1 to 10 MHz ultrasonic oscillation. It would be short, however, compared to
the acoustic transmission time in the tissue. Sound velocity in the body averages
about 1540 m/s. therefore, 1mm in distance requires 0.65 Microsecond on the
average.
The pulse of ultrasonic energy travels into the tissue. It is reflected from
tissue boundaries, causing echoes. By the time the echoes reach the transducer, the
pulse generator has turned off, and the echo creates an oscillation in the transducer
again. The echo is like that of a drum beat reverberating off a wall, except the
drum operates at a lower, audible frequency.
TASK 2 word association
One word connects each set of four below. All the words have medical
connections. What are they?
Electronics Biomedical Instrumentation – Part II – Unit 4
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 11
transplant failure
diseaserate
involuntary
relaxant
replacement
sex
labour
throbbing
pressure
donor
sugar

Circadian Manner
Clinical Marrow
Digestive Practitioner
General Reaction
General Rhythm
Heart Surgery
Malignant System
Milk Teeth
Plastic Trial
Surgical Tumour
Cardiac arrest => heart attack
No pain =>
Soft substance found inside calcified connective tissue =>
Knife instead of drugs =>
Twenty, to be replaced by thirty-two =>
Operating on appearances =>
Electronics Biomedical Instrumentation – Part II – Unit 4
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 13
Life ends, though the heart beats on =>
The way a doctor behaves to a patient =>
The effect of, for example, pollen =>
Test of a drug on a small group of people => Clinical trial
Cancer => Malignant tumour
Local doctor => General practitioner
Everyday the same old routine =>
Liver, pancreas, gall bladder, stomach, duodenum, etc =>
Proteins, carbohydrates, fats, vitamins and mineral: all in the correct proportions
=>
Electronics Biomedical Instrumentation – Part II – Unit 5
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 14

transducer in the frequency ranges from 1 to 10 MHz.
3. Since the applied voltage is sinusoidal, it sets up sinusoidal vibrations in the
crystal called ultrasound.
4. The acoustic impedance, or impedance to sound waves, is as high in the
transducer as in body tissue.
5. If this gel is rightly applied, the transducer can be damaged and skin burns
can happen.
Electronics Biomedical Instrumentation – Part II – Unit 5
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 15
6. Failures can also arise from breakage as a result of overheating.
TASK 2
Connectives “since, as” can be used to refer to the reason for something. In an
informal style, the same ideas are often expressed with ‘so’.
Eg: Copper is often used for cables since it is a good conductor.
Now link these ideas with reason connectives
1. The applied voltage is sinusoidal. (since). It sets up sinusoidal vibrations in
the crystal that are called ultrasound.
2. A heat-sensitive pellet expands. (As). It gets hot.
3. The pressure of the air in the plastic tube rises. (As). It is compressed by the
rising water.
4. Ultrasonic welding is better than heat welding. The materials are not
distorted. (Since)
5. Dirt and dust reduce effective light. Lamps must be kept clean. (As).
TASK 3
Look back in the text and find the reference for the words in italics.
1. … it generates a voltage high enough …
2. … change
its size and shape slightly …
3. … it sets up sinusoidal vibrations in the crystal that are …
4. … get

3. Dielectric heating provides rapid heat, and the heat produced uniformly
throughout the material. Dielectric heating can be easily controlled and
predictable.
4. Fluorescent lamps are better than filament lamps. The heat from fluorescent
lamps is much less than from filament lamps.
5. The bone absorbs more x-ray energy than water. This difference in x-ray
intensities on film will produce an image having good contrast properties.
Electronics Biomedical Instrumentation – Part II – Unit 6
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 17
Unit 6: General description – CLINTEK
TASK 1: Read the text and complete it using these words.
Semi-automated To read Depending
Major Are printed Directly
The CLINITEK 100 Urine Chemistry Analyzer (Fig 6.1) is a
……………………. Bench-top instrument designed to “read” Bayer Diagnostics
Reagent Strips for Urinalysis. The instrument system includes a Program Card that
contains the programming necessary for the CLINITEK 100 instrument
……………………. these Reagent Strips. The instrument is initially configured to
read MULTISTIX 10 SG Reagent Strips; in the United States, MULTISTIX 9 and
URISTIX 4 Reagent Strips are also qualified for use.
……………………. on the product being used, Bayer Diagnostics Reagent
Strips contain reagent areas for testing glucose, bilirubin, ketone (acetoacetic
acid), specify gravity, occult blood, pH, protein, urobilinogen, nitrite, and
leukocytes.
The CLINITEK 100 instrument is a reflectance photometer that analyzes
the color and intensity of the light reflected from the reagent area and displays the
results in clinically meaningful units. No calculations are required.
Figures show the ……………………. components of the CLINITEK 1000
instrument. Reagent Strips are loaded onto the reagent strip feed table, which will
automatically move out to the ‘load’ position when the instrument is first turned

on an x-y plot.
b. The dosage from ionizing radiation is cumulative because the probability of cell
damage ……………………. As more x-rays pass through the body.
c. This effect is the ……………………. in the frequency of a sound reflected by a
body approaching the source of the sound.
3. Use, using, used.
a. It is ……………………. to apply massage and deep-heat to muscle tissue.
b. For ……………………. as therapy. It is necessary to couple relatively high
power into the tissue.
c. It is difficult to get large values of contrast between soft tissues
……………………. x-rays.
TASK 4: Reagent Strip Feed Table
The Reagent Strip feed table is a two-piece assembly designed to correctly
hold and transport a Bayer Diagnostics Reagent Strip through the testing cycle. A
Reagent Strip that has been dipped into a urine specimen and had excess urine
removed must be correctly positioned in the strip holding channel, with the end of
the strip positioned against the rear barrier of the feed table insert. CAUTION:
Avoid placing objects in the path of or onto the feed table at any time during
instrument operation. Never push of pull the fees table during instrument
operation.
The feed table insert can be removed for cleaning and must always be
correctly repositioned on the feed table. The insert is held in position by two rails
and four plastic contact points, located under the insert. If a contact point becomes
damaged, the fees table insert will not be properly held in place on the feed table
and the Reagent Strip will not be properly positioned on the feed table insert.
Therefore, a defective feed table insert should always be replaced.
Electronics Biomedical Instrumentation – Part II – Unit 6
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 19
The feed table insert contains the white plastic calibration chip that is used
for instrument calibration. This calibration chip must be kept clean for proper

My ……………………………………………………………………………
2. I examined the patient fully.
I made ……………………………………………………………………………
3. I prescribed a course of antibiotics.
I wrote ……………………………………………………………………………
4. He suffered very little.
He experienced ……………………………………………………………………
5. We operated immediately.
Electronics Biomedical Instrumentation – Part II – Unit 6
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 20
The ……………………………………………………………………………
6. This disease can not be cured.
There is ……………………………………………………………………………
7. He has recovered fully.
He has made ………………………………………………………………………
8. The lab analysed the blood sample.
The lab made ……………………………………………………………………….
9. We found that the tissue was infected.
We found ……………………………………………………………………………
10. He has experienced six years of tropical work.
He has ……………………………………………………………………………
11. We replaced the patient’s hip.
The patient …………………………………………………………………………
12. His condition has degenerated.
There has been ……………………………………………………………………
13. The patient was referred to a specialist.
The patient was given ………………………………………………………………
14. The amount of sugar in the blood sample exceeded the norm.
There was …………………………………………………………………………
15. This is the time to withdraw the drugs treatment.

Those voltages are in the order of 10 mV; but typical EEG electrodes measure the
……………… activity propagated through skull bone and attenuated to levels
from 1 to 100 µV, primarily in the frequency range from 0.5 to 3000 Hz. These
potentials vary as function of position over the surface of the skull, making it
necessary for the EEG operator to select sets of ……………… grouped around the
frontal, parietal, temporal, or occipital lobes of the brain.
EEG Electrodes
Arrangement where inserted distance goes
Problems compensate method electrodes
In electroencephalograph, electrodes are placed in standard positions on the
skull in an arrangement referred to as the 10-20 system, a placement scheme
devised by the International Federation of Societies of Electroencephalography.
The electrodes in this ……………… are placed along a line drawn on the skull
from the root of the nose, the nasion, to the inion ossification or bump on the
occipital lobe. The first mark is placed 10% of the ……………… along the line,
and others are arranged at 20% intervals, hence the name 10-20 system. A similar
line is placed from one auricular to the other. A third line ……………… around
the circumference of the skull. A representative electrode arrangement placed at
intersections of these lines, ……………… the first letter of the electrode
designation F stands for frontal lobe, C for central suleus, P for parietal lobe, and
O for occipital lobe on the skull. Pg is the nasopharyngeal point and A is on the
ear lobe.
Electrode ……………… arise because of hair which tends to increase the
contact resistance. Surface electrodes may be made of silver, silver oxide disks
from 1 to 3 mm in diameter. A conductive paste is used to lower the electrode
resistance below 10 K
Ω and to ……………… for hair interference. The electrodes
may be covered with gauze and held with an adhesive such as collodion cement.
To lower its resistance further, the skin may be abraded, but this introduces
discomfort. Another ……………… for reducing the electrode resistance employs

remember the word: ‘GOAL’, GOAL ……………… for Good, Observe, Analyze
and Limit.
Electronic equipment that is broken usually shows very definite symptoms are
……………… important. Good technicians try to note all the symptoms before
proceeding. This demands a ……………… of the equipment. You must know
what the normal performance of a piece of equipment is in order to be able to
……………… what is abnormal. It is often ……………… to make some
adjustments or run some checks to be ……………… that the symptoms are
clearly identified. For example, if a radio receiver has a hum or whistle on one
station, several other stations should be ……………… into determine if the
Electronics Biomedical Instrumentation – Part II – Unit 7
Điện Tử Y Sinh 4 – Học Viện Kỹ Thuật Quân Sự 23
symptom persists. Another example might involve checking the sound from a tape
recorded on another machine known to be ……………… properly. These kinds of
adjustments and checks will help the technician to properly observe the symptoms.
TASK 4: We often use an infinitive to talk about purpose. We can also use in
order to
or so as to for this reason.
Link these sentences using infinitive verbs.
1. Microprocessors are now used. (to). Microprocessors control many household
items such as automatic washing-machines, dishwashers.
2. This instrument contains a triangular wave oscillator (which to). Wave
oscillator can be switched. Wave oscillator produces triangular and square.
3. Lower its resistance further. (to). The skin may be abraded.
4. A defibrillator creates a sustained myocardial depolarization of a patient’s
heart. (in order to). A sustained myocardial depolarization stops ventricular
fibrillation.
5. The burning fuel heats boiler. (to). Boiler produces steam.
6. I was beginning to feel alarm, but kept it to myself. (so as not). I did not want
to worry our children.