Slide 1Basic Concepts of Medical Instrumentation
Basic Sensors and Principles
Amplifiers and Signal Processing
The Origin of Biopotentials
Measurements of the Respiratory System
Chemical Biosensors
Elektrik akm ve geriliminin insan için zararl, öldürücü olma
deerlerini, frekans özelliklerini de göz önüne alarak
anlatn.(%20)
Duyarlk elemanlarmzn cevaplarnn zaman göre çklarnn: (giri çk
arasndaki gecikme var/yok, gecikmenin türü)
zero-order (%5)
firs-order (%5)
EKG iaretlerinin alglanmasn, elde edilen iaretin genlik ve frekans
özelliklerini, eklini ve anlamlarn anlatn. (%20)
Kan basncn (mekanik-analog) ölçme yöntemini (ölçülen deerlerin
anlamlarn belirterek) anlatn. (%15)
Bioelektrik empedans tanm, ölçmeleri, dijital terazide vücudun ya,
su deerlerinin belirlenmesi anlatn. (%20)
Sadece üst tarafndan eriilebilen 10 m derinlikte bir havuzunun
içindeki suyun seviyesiini en güvenli ekilde ölçmek, ve display
etmek için gerekli farkl iki sistemi tasarlay, çizin, anlatn.
Öneri-1(%5), Öneri-2(%5),
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
*
The probe contains two high intensity, monochromatic, light-
emitting diodes, one emitting red light (660 nm) and the second
infrared (940 nm) on one side and a photodetector on the other to
measure the amount of light transmitted through the finger.
Pulse oximetry
*
This audio frequency meter uses 555 IC as a monostable
multivibrator (one-shoot trigger). A monostable multivibrator can
act as a frequency-to-voltage converter because it produce a fixed
pulse width, with the repetition rate/density is proportional to
the triggering input frequency. Here is the circuit’s schematic
diagram:
For resistor R1, because it set the measurement range, it’s better
to use a rotary switch to select different values for different
ranges. For the ampere meter, you can use both analog or digital
ampere meter. A cheap dual-slope ADC digital meter is suitable
because its averaging characteristic, but a fast digital multimeter
can also be used although it may show some uncertainty because of
their fast sampling.
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
*
For this example, the discharge is underdamped (biphasic, also
referred to as a Gurvich
waveform) when the patient resistance is less than about 56Ω
because
Rpatient+Rinductor=56Ω+10Ω=66Ω<Rcritical=67Ω
In this case, the waveform is underdamped and produces a biphasic
(oscillating) waveform.
If the patient impedance is higher than 67Ω, the waveform is
overdamped (monophasic,
also referred to as an Edmark waveform). In this case the inductor
slows the rate of rise of the discharge current, reduces the
maximum voltage applied to the patient, and shapes
the waveform to produce a damped sinusoidal waveform. The current
delivered to the
patient gradually rises to a rounded peak and drops back to zero.
The discharge current
pulse duration is about 2.5L1/C1, about 2.5 to 3.5ms for most
defibrillators.
DESIGN AND DEVELOPMENT
OF MEDICAL ELECTRONIC
Figure 8.32 Schematic diagram of a damped sinusoidal waveform
defibrillator capable of delivering energies of up to 320 J into a
50-Ω
patient load through a 5-ms Edmark (monophasic) waveform. Charge
pushbutton SW2 energizes high-voltage transformer T1. C1 is charged
through the high-voltage rectifier network D1–D4 and R1. Meter M1
is calibrated to yield an estimate of energy (in joules) delivered
to the patient, assuming a load impedance of 50Ω. Defibrillation
energy is delivered to the patient by simultaneously pressing on
pushbuttons SW3 and SW4, which energize relay K1, which is used to
transfer the defibrillation charge from capacitor C1 to the patient
via pulse shaping inductor L1. R4 and R5 discharge C1 if the
defibrillation buttons are depressed without a suitable load across
the paddle electrodes or the
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
Required required
I = 7.5Amps.
Then I = 450/(230 × 0.01) = 175 A.
This is too much to be supplied by household mains.
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
DC Defibrillation (Fig. 12.10b)
1. Safety housings for electrodes–capacitor discharges only when
the electrodes are making
firm contact with the heart or chest wall.
2. Two set of electrodes - not interchangeable sockets
1. Internal 50–72 J (5–3 kV)
3. Meter indicates Joules
4. Charging time constant of 4 seconds
1. 0.25 M Ω × 16 μF
2. (charging resistor)
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
CAPACITIVE-DISCHARGE DC DEFIBRILLATORS
A short high-amplitude defibrillation pulse can be obtained by
using the
capacitive-discharge circuit shown in Figure 13.10. In this case, a
half-wave rectifier driven by a step-up transformer is used to
charge the capacitor C. A good rule of thumb is to keep charging
time under 10 s.
MEDICAL INSTRUMENTATION Application and Design
FOURTH EDITION John G. Webster, Editor
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
*
When external electrodes are used, energies as high as 400 J may
be
required.
The energy stored in the capacitor is given by the well-known
equation
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
resistive impedance (R) for the estimation
of human body composition is described.
This method is based upon the principle that the electrical
conductivity of the fat-free tissue mass (FFM) is far greater
than
that of fat.
Using an electrical impedance plethysmograph with a four
electrode
arrangement that introduces a painless signal (800 A at 50
kHz)
into the body.
from 44.6-98. 1 kg.
Total body water (TBW) determined by D2O dilution and total
body
potassium (TBK) from whole body counting were 50.6 ± 10.3 L
and
167.5 ± 38.1 g, respectively.
*
Tepe idrar akm hz erkeklerde 20 ml/sn, kadnlarda ise 25 ml/sn
üstünde normal oalrak kabul edilir
Uroflowmetry
The SEDIA F1 Flowmeter provides you with a convenient, cost
effective and easy to use solution for portable uroflowmetry.
Communication between the flow meter and your computer is via
Bluetooth connection. The SEDIA software is easily installed on
your Windows PC, allowing you to print reports from your own
printer.
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
Loop Voltage
Standard test circuit
Vc:3.0 V±0.1 V DC; VH: 0.9 V±0.1 V DC
Preheat time
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
Becquerel (Bq); 1 parçalanma/1 saniye
1Ci=3.7x1010 Bq 1 Ci=37GBq
IINLANMA DOZU
Röntgen (R) ; normal hava artlarnda (00C ve 760 mm Hg basnc)
havann 1kg’nda 2.58x10-4 Coulomb’luk elektrik yükü deerinde (+) ve
(-) iyonlar oluturan X veya g radyasyonu miktardr.
Coulomb / kilogram (C/kg) ; normal hava
artlarnda havann 1 kg’nda 1 Coulomb’luk elektrik
yükü deerinde (+) ve (-) iyonlar oluturan X veya g radyasyonu
miktardr.
1C/kg=3876 R1R=2.58x10-4 C/kg
SOURULMU DOZ
radiation oz (rad); nlanan maddenin 1 kg’nda 10-2
Joule’lük enerji sourulmas meydana getiren herhangi bir radyasyon
miktardr.
Gray (Gy) ; nlanan maddenin 1 kg’nda 1 Joule’lük
enerji sourulmas meydana getiren herhangi bir radyasyon
miktardr.
1Gy=100rad 1rad=0.01 Gy
DOZ EDEER
röntgen equivalent man (); 1 Röntgenlik X veya n ile ayn
biyolojik etkiyi oluturan herhangi bir radyasyon miktardr.
rem=(rad)x(WR)*
Sievert (Sv) ; 1 Gy’lik X ve g n ile ayn biyolojik etkiyi meydana
getiren herhangi bir radyasyon miktardr. Sv= (Gy)x(WR)*
1Sv=100 rem 1rem=0.01Sv
*
Prof.Dr.Sezgin ALSAN Nuclear Instrumentation
Normal background radiation varies from place to place but delivers
a dose equivalent in the vicinity of 2.4 mSv /year, or about
0.3 µSv/h.
The international limit for radiation exposure for nuclear workers
is 20 mSv per year, averaged over five years, with a limit of
50 mSv in any one year, however for workers performing
emergency services EPA guidance on dose limits is 100 mSv when
"protecting valuable property" and 250 mSv when the activity
is "life saving or protection of large populations. A 250 mSv
dose is estimated to increase one's lifetime risk of developing
fatal cancer from about 20% to about 21%, and chronic exposure of
100 mSv per year is the "lowest level at which any increase in
cancer is clearly evident," according to the International
Commission on Radiological Protection . Symptoms of radiation
poisoning typically emerge with a 1000 mSv total dose over a
day.
Prof.Dr.Sezgin ALSAN Biyomedikal Enstrümantasyon
Baz radyolojik tetkikler sonucu, ülke seviyelerine ve yaplan
tetkiklere göre, hastalarn maruz kald etkin dozlar.
TETKKLER
Seviye 1*
Seviye 2**
Seviye 3-4***